Luka Quality Assurance Manual (Eng)
Contents:
1 General ........................................................................................................................................................................................................ 3
1.01 Foreword ................................................................................................................................................................................................ 3
2. Quality assurance standards for air ducts .................................................................................................................................................... 4
A.1.00 Rectangular galvanised steel ducts ....................................................................................................................................................... 4
A.2.00 Embedded galvanised steel air ducts for residential buildings and floors equivalent to residential buildings ........................................ 13
A.3.00 Round galvanised steel ducts............................................................................................................................................................... 20
B.1.00 Rectangular aluminium ducts .............................................................................................................................................................. 31
B.2.00 Round aluminium ducts ....................................................................................................................................................................... 41
C.1.00 Rectangular stainless steel ducts.......................................................................................................................................................... 51
C.2.00 Round stainless steel ducts .................................................................................................................................................................. 61
D.1.00 Rectangular plastic ducts ..................................................................................................................................................................... 72
D.2.00 Round plastic ducts ............................................................................................................................................................................. 81
E.1.00 Rectangular mineral wool ducts ........................................................................................................................................................... 86
F.1.00 Rectangular rigid foam ducts................................................................................................................................................................ 92
G.1.00 Round flexible ducts, or hoses ........................................................................................................................................................... 100
G.2.00 Flexible aluminium hoses .................................................................................................................................................................. 102
G.3.00 Flexible aluminium foil hoses ............................................................................................................................................................ 103
G.4.00 Flexible plastic hoses ......................................................................................................................................................................... 104
H.1.00 Internal and external coating of air ducts .......................................................................................................................................... 105
I.1.00 Thermal insulation of rectangular and round air ducts ........................................................................................................................ 107
J.1.00 Fire-resistant insulation and sheathing of metal air ducts ................................................................................................................... 114
K.1.00 Internal cleaning of air ducts.............................................................................................................................................................. 123
L.1.00 Installation instructions ..................................................................................................................................................................... 125
M.1.00 Airtightness ...................................................................................................................................................................................... 173
3.01 Quality control ..................................................................................................................................................................................... 182
3.02 Quality guarantee ................................................................................................................................................................................ 183
3.03 External quality control by TÜV Rheinland Nederland BV ................................................................................................................ 184
3.04 Policy statement of members and associate members of LUKA ......................................................................................................... 185
3.05 Contract specifications ........................................................................................................................................................................ 186
1 General
1.01 Foreword
The purpose of the Luka Quality Assurance Manual is to serve as the basis for the quality attributes of the products
and services guaranteed by Luka members and associate members. It also gives a clear insight into the quality
philosophy of all the members, and the methodology of quality control by the independent institute TÜV Rheinland
Nederland BV, a partner of Luka. With this publication, Luka’s Environment and Technology Committee
(Commissie Milieu & Techniek: CMT) hopes to have again achieved extra added value for the HVAC sector. Luka
and those who assisted in compiling this manual have taken the greatest possible care with collecting, processing
and formulating the information contained in this manual. Nevertheless, the possibility cannot be excluded here that
this manual is incomplete or contains inaccuracies or errors. Therefore anyone who uses this manual and the
information stated therein personally accepts the risk of this. Luka and those who assisted in compiling this manual
exclude all liability for both damage that may result from the use of this information and damage that could arise as
a result of the omissions, inaccuracies or errors of this manual. No part of this manual may be reproduced and/or
transmitted in any form or by any means, printing, copying or otherwise, without the prior written permission of the
board of Luka. The publication of this updated manual entails that the “May 2004” version is no longer applicable.
2. Quality assurance standards for air ducts
A.1.00 Rectangular galvanised steel ducts
A.1.01 sheet quality
For manufacturing galvanised air ducts, sheet steel of DX51 DZ 275 MAC quality, coated on both
sides with a zinc layer according to the Sendzimir process, shall be used. The layer thickness shall be
275 g/m2 for both sides, measured according to the trihedral test. Sheet quality / zinc quality shall be
in accordance with EN 10142, and tolerances shall be in accordance with EN 10143 (the zinc layer
having an average thickness of 20 microns on each side).
A.1.02 sheet thickness
Galvanised air ducts shall made in a sheet thickness that is dependent upon the largest duct side, as
specified below.
The air ducts shall be manufactured at this thickness to ensure sufficient rigidity against distortion and
to prevent disturbing vibrations.
Based on the largest duct side, the following apply as minimum sheet thicknesses:
A.1.03 transverse joints
For rectangular air ducts, various types of transverse joints can be used. These are company dependent,
the quality of the sheet material from which the joint profiles shall be formed at least satisfying the
requirements of the material from which the duct is manufactured.
These transverse joints can (depending on the company) be attached to the duct by rolling, or fastened
to the duct by means of projection welds, spot welds, screws or pop rivets. The transverse joints shall
be coupled with clips, slide plates or clamps at a maximum centre-to-centre distance of 500 mm (see
drawing). To provide airtightness, a closed-cell sealing tape shall be applied between the transverse
joints, the minimum dimensions being 18 x 4 mm (W x H) and all four corners being provided with
galvanised bolts and nuts of at least size M6 x 20.
If slide plates are used over the whole perimeter of the duct, the bolts and nuts at the corners may be
omitted. Where necessary, to provide airtightness, permanently plastic sealant shall be applied
internally or externally.
A.1.04 longitudinal joints
In principle, longitudinal joints between duct sections shall be made as a folded seam. Where
necessary, to provide airtightness, permanently plastic sealant shall be applied internally or externally.
A.1.05 reinforcements
Air ducts shall be made with a rigidity sufficient to prevent disturbing vibrations and distortion.
Assuming that the recommended minimum sheet thickness according to A.1.02 is used, this applies to
rectangular metal ducts when the largest side of the cross-section is ≤ 400 mm. Additional provisions
are required when this dimension is exceeded. The amount of the excess shall determine the necessary
provisions.


cross-breakings; crosswise embossments normally directed outwards;
corrugations or folds: usually made at right-angles to the longitudinal axis of the duct at a
mutual distance not exceeding 500mm.
For ducts with a side dimension > 800 mm, the previously mentioned provisions for the duct walls
apply, surfaces with an area greater than 1.5 m2 being additionally reinforced by partioning into
subsections not greater than 1 m2. These additional reinforcements shall be fitted internally or
externally in the form of strips, profiles, tubes or plates.
A.1.06 dimensions
The nominal dimensions of the air ducts shall be given in mm and refer to the inside dimensions with a
tolerance of +0 to -4 mm. The dimensions shall be standardised according to EN 1505 and can be
selected as indicated in the table of standard dimensions.
A.1.07 exposed ductwork
If a section of the air duct system in an air-conditioning installation is intended as “exposed ductwork”,
it shall be constructed as the rest of the ductwork, unless otherwise specified. When ductwork is
intended as exposed ductwork, external stickers and labelling shall be removed, while the required
airtightness shall be obtained by internal application of sealant. Additional measures in the context of
exposed ductwork are not normally included in the standard construction.
A.1.08 bends
A.1.08.1 symmetrical bends
In principle, symmetrical bends have a round shape, i.e. with an inside and an outside radius; the inside
radius shall be at least 100 mm. (For floor or wall openings where there is no room for an inside
radius, a right-angled inside bend shall be used.) To limit the friction in a bend, the bends shall be
provided with vanes. Vanes are not required in the following cases:


a bend of 45° or less;
a duct with a width of 400 mm or less.
The vanes shall be positioned according to the following table.
A.1.08.2 reducing bends
In the case of reducing bends, the smallest duct width shall determine the number of vanes according
to the above table. The ratio for the position of the vanes at the largest duct width is then equal to the
ratio for the vanes at the smallest duct width.
A.1.08.3 construction of vanes
Vanes shall be made of single-thickness sheet. The sheet material shall be the same as that used for the
duct. The construction and fastening shall be of sufficient strength, and the ends of the vanes shall be
reinforced.
A.1.09 reducing couplings
Reducing couplings shall be made in such a way that the upper angle α may in principle be 60°
maximum.
A.1.10 branches
A branch (a take-off in an ongoing section of main duct) can be made by means of a fitting, either
rectangular or round. Technical aspects of air flow design co-determine the type, as shown in the
drawings below.
A.1.11 forks
A fork is a subdivision of a main duct into two ongoing ducts.
Examples of forks are:
A.1.12 adjustable dampers
Adjustable dampers serve for the regulation of an installation and shall be
made manually adjustable. They shall be provided with a reliable
securing device, which also shows the damper setting. The damper blade,
made of the same material as the air duct, shall be made of singlethickness sheet with a thickness of at least 1.25 mm, a maximum blade
width (B) of 500 mm and a maximum surface area of 0.25 m2. The edges
of the damper blades shall be rounded and reinforced parallel to the axis.
A.1.13 tolerances
The maximum tolerance for the length of a straight duct is ±0.005 x L.
The tolerance for the rectangular dimensions is +0 to -4 mm.
The maximum tolerance for angles is ± 2°.
A.2.00 Embedded galvanised steel air ducts for
residential buildings and floors equivalent to
residential buildings
(intended for embedding in the concrete floor)
A.2.01 sheet quality
For manufacturing galvanised air ducts, sheet steel of minimum DX51 D 150 MAC quality, coated on
both sides with a zinc layer according to the Sendzimir process, shall be used. The layer thickness shall
be 150 g/m2 for both sides, measured according to the trihedral test. Sheet quality / zinc quality shall be
in accordance with EN 10142, and tolerances shall be in accordance with EN 10143 (the zinc layer
having an average thickness of approx. 10 microns on each side).
A.2.02 sheet thickness
Galvanised air ducts shall be made in a sheet thickness that is dependent upon the largest duct side. The
embedded air ducts with the dimensions 170 x 70 and 170 x 80 shall be made in a sheet thickness of 0.5
mm, and with the dimensions 200 x 80 and 220 x 80 in a sheet thickness of 0.6 mm.
Other sizes can be made on a customer-specific basis.
A.2.03 transverse joints
For rectangular embedded ducts, the transverse joints shall be made as a slide joint, using a coupling or
sleeve.
This joint shall be fixed using self-tapping screws or where possible with spot welds and then finished
with tape, in such a way that no water or cement can enter the air duct.
A.2.04 longitudinal joints
In principle, longitudinal joints shall be made as a seam weld, folded seam or spot weld.
Where necessary, to provide airtightness, permanently plastic sealant shall be applied internally or
externally.
A.2.05 dimensions
The ducts shall be made in the following dimensions: 170 x 70 mm, 170 x 80 mm, 200 x 80 mm, 220 x
80 mm.
A.2.06 various types of rectangular embedded ducts
A.2.06.1 straight duct
The straight ducts shall be supplied in standard lengths of 3 m.
A.2.06.2 bends
Bends shall be supplied in standard implementations as 90° or 45° bend and shall be streamlined.
A.2.06.3 coupling or sleeve
Couplings or sleeves shall be supplied in standard lengths of 80, 100, 125, 200, 300 or 600 mm,
depending on the supplier. Sleeves that are longer than 80 mm are also called connectors.
A.2.06.4 end cover
End covers shall be supplied in all the standard sizes stated above.
A.2.06.5 T-pieces
T-pieces shall be supplied with a minimum inside radius of 100 mm.
A.2.06.6 right-angled side fitting
Using a right-angled side fitting, a T-piece with 90° internal angles can be constructed by making an
opening in a straight duct the same size as the side fitting. This is then attached to the straight duct by
means of self-tapping screws (with a maximum length of 13mm), after which the joint is covered with
tape or made airtight with sealant. The side fitting can also be attached at 45°.
A.2.06.7 round connecting collar or round flanged connector
These shall be supplied with inside diameters Ø 80, Ø 100, Ø 125, Ø 150, Ø 160, Ø 180 and Ø 200,
with a length that depends on the supplier and on the floor thickness. These connections can also be
made at 45°.
A.2.06.8 rectangular saddle on round tube (saddle piece)
Rectangular saddles shall be supplied for a round tube Ø 180 through to Ø 500.
The branch dimensions are: 170 x 70, 170 x 80, 200 x 80 and 220 x 80.
A.2.06.9 bevel angle
These are straight duct sections with a cut-off angle on the side of the cover, provided with a round
connecting mouth. The bevel angle shall be available as a left, right or symmetrical type, with a
connecting mouth of Ø 125, Ø 150, Ø 160 or Ø 180 connection.
A.2.06.10 reducing couplings
Reducing couplings shall be made in such a way that the upper angle may in principle be 45° maximum.
These reducing couplings can be made as rectangular to round, or rectangular to rectangular.
A.2.07 tolerances
The maximum tolerance for the length of a straight duct is ±0.005 x L.
The tolerance for the rectangular dimensions is +0 to -4 mm.
The maximum tolerance for angles is ±2°.
A.2.08 installation
The embedded ducts shall be secured on the concrete floor in such a way that the duct sections cannot
start to float when the concrete is poured. This shall usually be done with perforated support strapping
that goes round the duct and is fastened to the concrete on both sides using nail plugs. There are several
methods for sufficiently fastening the embedded duct, but the duct must be fixed at least every 2 metres.
It also often occurs that the ducts that are to be embedded are delivered prefabricated to the construction
site. Dented and bent ducts must not be installed. All apertures must be closed by means of plastic caps
(mortar covers).
The construction contractor shall be responsible for ensuring that the openings are sufficiently supported
to prevent the duct flanged connectors from sagging.
A.2.09 round air ducts (for embedding in concrete floor)
See section A3.00 “Round galvanised steel ducts”.
In supplementation of section A3.00, in residential buildings use is also often made of so-called “pleated
bends”.
These bends shall be available in diameters Ø 80, 100, 125, 150, 160, 180 and 200 mm.
The available angles shall be: 15, 30, 45, 60 and 90º.
The material, thicknesses, tolerances etc. shall be the same as for the pressed bends, as stated in section
A3.00.
In addition, in the case of embedded ducts, so-called embedded pots are used. These are mainly used to
make a transition from a horizontal duct (Ø 80 mm) in the floor to a vertical branch in the room, for the
purpose of e.g. connecting an exhaust and/or supply vent in the room concerned.
The available diameters shall be: Ø 100 and 125 mm. The branch diameter shall be Ø 80 mm. This
branch can be made either single or double. Dimensions, thicknesses, material etc. shall be as stated in
section A3.00.
Remark:
Ducts that are not embedded in the concrete are subject to the data, requirements etc. stated elsewhere in
this Manual.
A.2.10 airtightness
The airtightness of the embedded ducts must comply with Airtightness Class C.
In the case of embedded ducts in residential buildings, if required, the system shall be pressure tested
before the concrete is poured, regardless of the number of m². This contrasts with what is stated in the
section “Airtightness” elsewhere in this Manual. Because these ducts are embedded in concrete, the
joints and the embedded duct itself must be leak-tight to cement water. After being embedded, the ducts
are incorporated in the concrete floor, and shall be deemed to be airtight.
If higher requirements of airtightness of the duct system are imposed (e.g. for reasons of energy saving),
these must be explicitly stated in the specifications, so that the construction of the air duct system can be
adjusted accordingly.
The contract specifications can then read as follows:
All the supplied air ducts, accessories and hoses must comply with their respective EN standards. The
complete air flow path, both supply and exhaust, between the air-conditioning unit and the grilles (i.e.
including the grille plenums, if present) must be supplied and installed in accordance with the quality
and execution standards laid down in the Luka Quality Assurance Manual, digital edition 2014, in
compliance with Airtightness Class C as a minimum..
The airtightness must be tested and demonstrated by means of a leakage test report.
The quality and execution of the air flow path must be satisfactorily demonstrated to the construction
site management, and confirmed by means of a certificate.
A.3.00 Round galvanised steel ducts
A.3.01 sheet quality
For manufacturing galvanised air ducts, sheet steel of minimum DX51 DZ 275
MAC quality, coated on both sides with a zinc layer according to the Sendzimir
process, shall be used. The layer thickness shall be 275 g/m² for both sides,
measured according to the trihedral test. Sheet quality / zinc quality shall be in
accordance with EN 10142, and tolerances shall be in accordance with EN 10143
(the zinc layer having an average thickness of approx. 20 microns on each side).
A.3.02 sheet thickness
A.3.02.1 tubes
Galvanised air ducts shall be made in a sheet thickness that is dependent upon the
diameter, as specified below.
Based on the diameter, the following apply as minimum sheet thicknesses in
standard implementations:
A.3.02.2 fittings
Fittings shall be made in a sheet thickness that is dependent upon the diameter.
Based on the diameter, the following apply as minimum sheet thicknesses in
standard implementations:
A.3.03 joints in tubes
The joints in the spiral-wound strip shall be made as a flat folded seam, providing
sufficient rigidity and airtightness.
A.3.04 joints in fittings
The seam joints in fittings shall be made in such a way that sufficient rigidity and
airtightness are obtained. These joints shall be made by welding or folding.
Any damage to the zinc layer that may result in rust must be carefully coated with
a corrosion-resistant paint.
A.3.05 tube length
Tubes shall be supplied in standard lengths of 3000 or 6000 mm. For technical
reasons, tube lengths shall in principle be not less than the tube diameter, with a
minimum length of 300 mm.
A.3.06 diameters
The tubes shall be made in standard diameters according to EN 1506, namely 63 80 - 100 - 125 - 160 - 200 - 250 - 315 - 400 - 500 - 630 - 800 - 1000 and 1250
mm. Additional sizes stated in EN 1506 are: 150 - 300 - 355 - 450 - 560 - 710 900 - 1120 mm.
A.3.07 bends
With the exception of diameters of 63 and 80 mm, for which the curve radius shall
be 100 mm, the shape of bends shall normally be determined by a radius,
measured across the centre of the bend, that is equal to the tube diameter.
Standard bends shall have angles of 15°, 30°, 45°, 60° and 90° in pressed or
segmented construction with a tolerance of ±2°.
Segmented bends ≥45° shall consist of at least 3 segments.
A.3.08 reducing couplings
Reducing couplings may be either symmetrical or asymmetrical, with an upper
angle of minimum 15° and maximum 60°. Pressed reducing couplings may have a
maximum upper angle of 90°. Symmetrical reducing couplings shall be used as
standard.
A.3.09 branches
A branch (a take-off in an ongoing section of main duct) can be made
by means of a:



saddle piece, in combination with a straight tube;
T-piece, as a complete fitting;
4-way coupling, as a complete fitting;
and can be implemented as standard at an angle of 90° or 45°. For
technical reasons, angles < 45° should be avoided.
A.3.10 forks
A fork is a subdivision of a main duct into two ongoing ducts.


breech (Y-piece);
inverted T-piece.
If a breech is used, the fork can be made at an angle α = 90° or 60°. If an
inverted T-piece is used, the fork can be made at an angle α = 180°.
A.3.11 coupling pieces
These are used as standard in:

- joints between adjacent tubes; This fitting, made of the same material as the
tubes and provided with a buffer edge, creates an internal joint.

- joints between adjacent fittings; This fitting, made of the same material as
the tubes, is of smooth construction and creates an external joint.
The insert length of the fittings shall be based on EN 1506. For overlaps, the
following minimum lengths shall apply:
The joints shall be fixed using self-tapping screws and finished with:






tape with synthetic rubber mass (= self-vulcanising shrink tape);
PVC tape: only for exhaust ducts;
aluminium tape: only for exhaust ducts;
linen tape: only for exhaust ducts;
reinforced PE tape with acrylic adhesive mass;
2-component strip
These tapes must be applied in accordance with the supplier’s recommendations.
When round fittings with a rubber seal (so-called “Safe”) are used, the finishing
with tape shall normally be omitted in the case of once-only installation.
A.3.12 adjustable dampers
Adjustable dampers serve for the regulation of an installation and shall be made
manually adjustable. They shall be provided with a reliable securing device,
which also shows the damper setting. For surface areas up to 0.3 m2, the damper
blade, made of the same material as the air duct, shall be made of singlethickness sheet. If the surface area is greater, the blade shall either be made of
double-thickness sheet or be reinforced. The dampers shall be provided with
reliable and airtight bearings.
Perforated damper blades should be avoided.
A 3.13 end covers
Covers shall be made of the same material as the tubes.
A.3.14 tolerances
The maximum tolerance for the length of a duct is ±0.005 x L.
The tolerance for the diameters is specified in the adjacent table.
The maximum tolerance for angles is ±2°.
B.1.00 Rectangular aluminium ducts
B.1.01 sheet quality
For manufacturing rectangular aluminium air ducts, sheet material of Al 99.5 /
EN AW 1050A quality shall generally be used. For specific applications,
seawater-resistant aluminium of AlMg3 / EN AW 5754 quality can be used.
B.1.02 sheet thickness
Aluminium air ducts shall be made in a sheet thickness that is dependent upon
the largest duct side. The air ducts shall be manufactured at this thickness to
ensure sufficient rigidity against distortion and to prevent disturbing vibrations.
Based on the largest duct side, the following apply as minimum sheet
thicknesses:
For technical reasons, thicknesses greater than 1.50 mm shall be avoided.
B.1.03 transverse joints
For rectangular air ducts, various types of transverse joints can be used. These
are company dependent, the quality of the sheet material from which the joint
profiles shall be formed at least satisfying the requirements of the material from
which the duct is manufactured.
These transverse joints can (depending on the company) be attached to the duct
by rolling, or fastened to the duct by means of projection welds, spot welds,
screws or pop rivets.
The transverse joints shall be coupled with clips, slide plates or clamps at a
maximum centre-to-centre distance of 500 mm (see drawing). These fasteners
shall be made of aluminium / stainless steel.
To provide airtightness, a closed-cell sealing tape shall be applied between the
transverse joints, the minimum dimensions being 18 x 4 mm (W x H) and all
four corners being provided with stainless steel bolts and nuts of at least size M6
x 20.
If slide plates are used over the whole perimeter of the duct, the bolts and nuts at
the corners may be omitted. Where necessary, to provide airtightness,
permanently plastic sealant shall be applied internally or externally.
B.1.04 longitudinal joints
In principle, longitudinal joints between duct sections shall be made as a folded
seam. Where necessary, to provide airtightness, permanently plastic sealant shall
be applied internally or externally.
B.1.05 reinforcements
Air ducts shall be made with a rigidity sufficient to prevent disturbing vibrations
and distortion. Assuming that the recommended minimum sheet thickness
according to B.1.02 is used, this applies to rectangular aluminium ducts when
the largest side of the cross-section is ≤ 400 mm. Additional provisions are
required when this dimension is exceeded. The amount of the excess shall
determine the necessary provisions. For ducts with a side dimension of > 400
mm to ≤ 800 mm, the duct walls shall be made as follows:


cross-breakings: crosswise embossments normally directed outwards;
corrugations or folds: usually made at right-angles to the longitudinal axis of
the duct at a mutual distance not exceeding 500 mm.
For ducts with a side dimension > 800 mm, the previously mentioned provisions
for the duct walls apply, surfaces with an area greater than 1.5 m2 being
additionally reinforced by partitioning into subsections not greater than 1 m2.
These additional reinforcements shall be fitted internally or externally in the
form of strips, profiles, tubes or plates.
B.1.06 dimensions
The nominal dimensions of the air ducts shall be given in mm and refer to the
inside dimensions with a tolerance of +0 to -4 mm. The dimensions shall be
standardised according to EN 1505 and can be selected as indicated in the table
of standard dimensions.
B.1.07 exposed ductwork
If a section of the air duct system in an air-conditioning installation is intended
as "exposed ductwork", it shall be constructed as the rest of the ductwork, unless
otherwise specified. When ductwork is intended as exposed ductwork, external
stickers and labelling shall be removed, while the required airtightness shall be
obtained by internal application of sealant. Additional measures in the context of
exposed ductwork are not normally included in the standard construction.
B.1.08 bends
B.1.08.1 symmetrical bends
In principle, symmetrical bends have a round shape, i.e. with an inside and an
outside radius; the inside radius shall be at least 100 mm. (For floor or wall
openings where there is no room for an inside radius, a right-angled inside bend
can be used.) To limit the friction in a bend, the bends shall be provided with
vanes.
Vanes are not required in the following cases:


a bend of 45° or less;
duct with a width of 400 mm or less.
The vanes shall be positioned according to the following table.
B.1.08.2 reducing bends
In the case of reducing bends, the smallest duct width shall determine the
number of vanes according to the above table. The ratio for the position of the
vanes at the largest duct width is then equal to the ratio for the vanes at the
smallest duct width.
B.1.08.3 construction of vanes
Vanes shall be made of single-thickness sheet. The sheet material shall be the
same as that used for the duct. The construction and fastening shall be of
sufficient strength, and the ends of the vanes shall be reinforced.
B.1.09 reducing couplings
Reducing couplings shall be made in such a way that the upper angle α may in
principle be 60° maximum.
B.1.10 branches
A branch (a take-off in an ongoing section of main duct) can be made by means
of a fitting, either rectangular or round. Technical aspects of air flow design codetermine the type, as shown in the drawings below.
B.1.11 forks
A fork is a subdivision of a main duct into two ongoing ducts.
Examples of forks are:
B.1.12 adjustable dampers
Adjustable dampers serve for the regulation of an installation and shall be made manually adjustable. They shall be
provided with a reliable securing device, which also shows the damper setting. The damper blade, made of the same
material as the air duct, shall be made of single-thickness sheet with a thickness of at least 1.25 mm, a maximum
blade width (B) of 500 mm and a maximum surface area of 0.25 m2. The edges of the damper blades shall be
rounded and reinforced parallel to the axis.
B.1.13 tolerances
The maximum tolerance for the length of a straight duct is ±0.005 x L.
The tolerance for the rectangular dimensions is +0 to -4 mm.
The maximum tolerance for angles is ±2°.
B.2.00 Round aluminium ducts
B.2.01 sheet quality
For manufacturing round aluminium air ducts, sheet material of
AlMg3 / EN AW 5754 Mill Finish quality according to EN 573/485
shall be used.
B.2.02 sheet thickness
B.2.02.1 tubes
Aluminium air ducts shall be made in a sheet thickness that is
dependent upon the diameter, as specified below.
Based on the diameter, the following apply as minimum sheet
thicknesses in standard implementations::
B.2.02.2 fittings
Fittings shall be made in a sheet thickness that is dependent upon the
diameter.
Based on the diameter, the following apply as minimum sheet
thicknesses in standard implementations:
B.2.03 joints in tubes
The joints in the spiral-wound strip shall be made as a flat folded
seam, providing sufficient rigidity and airtightness.
B.2.04 joints in fittings
The seam joints in fittings shall be made in such a way that sufficient
rigidity and airtightness are obtained. These joints shall be made by
welding or folding.
B.2.05 tube length
Tubes shall be supplied in standard lengths of 3000 or 6000 mm. For
technical reasons, tube lengths shall in principle be not less than the
tube diameter, with a minimum length of 300 mm.
B.2.06 diameters
The tubes shall be made in standard diameters according to EN 1506,
namely 63 - 80 - 100 - 125 - 160 - 200 - 250 - 315 - 400 - 500 - 630 800 - 1000 and 1250 mm. Additional sizes stated in EN 1506 are: 150
- 300 - 355 - 450 - 560 - 710 - 900 - 1120 mm.
B.2.07 bends
With the exception of diameters of 63 and 80 mm, for which the
curve radius shall be 100 mm, the shape of bends shall normally be
determined by a radius, measured across the centre of the bend, that is
equal to the tube diameter. Standard bends shall have angles of 15°,
30°, 45°, 60° and 90° in segmented construction with a tolerance of
±2°. Segmented bends of 45° shall consist of at least 3 segments.
B.2.08 reducing couplings
Reducing couplings may be either symmetrical or asymmetrical, with
an upper angle of minimum 15° and maximum 60°. Pressed reducing
couplings may have a maximum upper angle of 90°. Symmetrical
reducing couplings shall be used as standard.
B.2.09 branches
A branch (a take-off in an ongoing section of main duct) can be made
by means of a:



saddle piece, in combination with a straight tube;
T-piece, as a complete fitting;
4-way coupling, as a complete fitting;
and can be implemented as standard at an angle of 90° or 45°. For
technical reasons, angles < 45° should be avoided.
B.2.10 forks
A fork is a subdivision of a main duct into two ongoing ducts. It can
be made by means of a:


breech (Y-piece);
inverted T-piece.
If a breech is used, the fork can be made at an angle α = 90° or 60°. If
an inverted T-piece is used, the fork can be made at an angle α =
180°.
B.2.11 coupling pieces
These are used as standard in:


joints between adjacent tubes; This fitting, made of the same
material as the tubes and provided with a buffer edge, creates an
internal joint.
joints between adjacent fittings; This fitting, made of the same
material as the tubes, is of smooth construction and creates an
external joint.
The insert length of the fittings shall be based on EN 1506. For
overlaps, the following minimum lengths shall apply:/p>
The joints shall be fixed using self-tapping screws and finished with:






tape with synthetic rubber mass (= self-vulcanising shrink tape);
PVC tape: only for exhaust ducts;
aluminium tape: only for exhaust ducts;
linen tape: only for exhaust ducts;
reinforced PE tape with acrylic adhesive mass;
2-component strip.
These tapes must be applied in accordance with the supplier’s
recommendations.
When round fittings with a rubber seal (so-called “Safe”) are used,
the finishing with tape shall normally be omitted in the case of onceonly installation.
B.2.12 adjustable dampers
Adjustable dampers serve for the regulation of an installation and
shall be made manually adjustable. They shall be provided with a
reliable securing device, which also shows the damper setting. For
surface areas up to 0.3 m2, the damper blade, made of the same
material as the air duct, shall be made of single-thickness sheet. If the
surface area is greater, the blade shall either be made of doublethickness sheet or be reinforced. The dampers shall be provided with
reliable and airtight bearings.
Perforated damper blades should be avoided.
B.2.13 end covers
Covers shall be made of the same material as the tubes.
B.2.14 tolerances
The maximum tolerance for the length of a duct is ±0.005 x L.
The tolerance for the diameters is specified in the adjacent table.
The maximum tolerance for angles is ±2°.
C.1.00 Rectangular stainless steel ducts
C.1.01 sheet quality
For manufacturing rectangular stainless steel air ducts, sheet of X 5 CrNi-18-10-1.4301
quality according to EN 10088-2 (AISI 304) shall generally be used. For specific
applications, stainless steel of X 5 CrNi-18-10-1.4404 quality according to EN 10088-2
(AISI 316) can be used.
C.1.02 sheet thickness
Stainless steel air ducts shall be made in a sheet thickness that is dependent upon the
largest duct side, as specified below. The air ducts shall be manufactured at this thickness
to ensure sufficient rigidity against distortion and to prevent disturbing vibrations. Based
on the largest duct side, the following apply as minimum sheet thicknesses:
For technical reasons, thicknesses greater than 1.00 mm shall be avoided.
C.1.03 transverse joints
For rectangular air ducts, various types of transverse joints can be used. These are
company dependent, the quality of the sheet material from which the joint profiles shall
be formed at least satisfying the requirements of the material from which the duct is
manufactured.
These transverse joints can (depending on the company) be attached to the duct by
rolling, or fastened to the duct by means of projection welds, spot welds, screws or pop
rivets.
The transverse joints shall be coupled with clips, slide plates or clamps at a maximum
centre-to-centre distance of 500 mm (see drawing). These fasteners shall be made of
stainless steel. To provide airtightness, a closed-cell sealing tape shall be applied between
the transverse joints, the minimum dimensions being 18 x 4 mm (W x H) and all four
corners being provided with stainless steel bolts and nuts of at least size M6 x 20. If slide
plates are used over the whole perimeter of the duct, the bolts and nuts at the corners may
be omitted. Where necessary, to provide airtightness, permanently plastic sealant shall be
applied internally or externally.
C.1.04 longitudinal joints
In principle, longitudinal joints between duct sections shall be made as a folded seam.
Where necessary, to provide airtightness, permanently plastic sealant shall be applied
internally or externally.
C.1.05 reinforcements
Air ducts shall be made with a rigidity sufficient to prevent disturbing vibrations and
distortion. Assuming that the recommended minimum sheet thickness according to
C.1.02 is used, this applies to rectangular metal ducts when the largest side of the crosssection is ≤ 400 mm. Additional provisions are required when this dimension is exceeded.
The amount of the excess shall determine the necessary provisions..
For ducts with a side dimension of > 400 mm to ≤ 800 mm, the duct walls shall be made
as follows:
- cross-breakings: crosswise embossments normally directed outwards;
- corrugations or folds: usually made at right-angles to the longitudinal axis of the duct at
a mutual distance not exceeding 500 mm.
For ducts with a side dimension > 800 mm, the previously mentioned provisions for the
duct walls apply, surfaces with an area greater than 1.5 m2 being additionally reinforced
by partitioning into subsections not greater than 1 m2. These additional reinforcements
shall be fitted internally or externally in the form of strips, profiles, tubes or plates.
C.1.06 dimensions
The nominal dimensions of the air ducts shall be given in mm and refer to the inside
dimensions with a tolerance of +0 to -4 mm. The dimensions shall be standardised
according to EN 1505 and can be selected as indicated in the table of standard
dimensions.
C.1.07 exposed ductwork
If a section of the air duct system in an air-conditioning installation is intended as
“exposed ductwork”, it shall be constructed as the rest of the ductwork, unless otherwise
specified. When ductwork is intended as exposed ductwork, external stickers and
labelling shall be removed, while the required airtightness shall be obtained by internal
application of sealant. Additional measures in the context of exposed ductwork are not
normally included in the standard construction.
C.1.08 bends
C.1.08.1 symmetrical bends
In principle, symmetrical bends have a round shape, i.e. with an inside and an outside
radius; the inside radius shall be at least 100 mm. (For floor or wall openings where there
is no room for an inside radius, a right-angled inside bend can be used.) To limit the
friction in a bend, the bends shall be provided with vanes.Vanes are not required in the
following cases:
- a bend of 45° or less;
- a duct with a width of 400 mm or less.
The vanes shall be positioned according to the following table.
C.1.08.2 reducing bends
In the case of reducing bends, the smallest duct width shall determine the number of
vanes according to the above table. The ratio for the position of the vanes at the largest
duct width is then equal to the ratio for the vanes at the smallest duct width.
C.1.8.3 construction of vanes
Vanes shall be made of single-thickness sheet. The sheet material shall be the same as
that used for the duct. The construction and fastening shall be of sufficient strength, and
the ends of the vanes shall be reinforced.
C.1.09 reducing couplings
VReducing couplings shall be made in such a way that the upper angle α may in principle
be 60° maximum.
C.1.10 branches
A branch (a take-off in an ongoing section of main duct) can be made by means of a
streamlined fitting, either rectangular or round. Technical aspects of air flow design codetermine the type, as shown in the drawings below.
C.1.11 forks
A fork is a subdivision of a main duct into two ongoing ducts.
Examples of forks are:
C.1.12 adjustable dampers
Adjustable dampers serve for the regulation of an installation and shall be made manually adjustable. They shall be
provided with a reliable securing device, which also shows the damper setting. The damper blade, made of the same
material as the air duct, shall be made of single-thickness sheet with a thickness of at least 1.25 mm, a maximum
blade width (B) of 500 mm and a maximum surface area of 0.25 m2. The edges of the damper blades shall be
rounded and reinforced parallel to the axis.
C.1.13 tolerances
The maximum tolerance for the length of a straight duct is ±0.005 x L.
The tolerance for the rectangular dimensions is +0 to -4 mm.
The maximum tolerance for angles is ±2°.
C.2.00 Round stainless steel ducts
C.2.01 sheet quality
For manufacturing round stainless steel air ducts, sheet steel of X 5 CrNi-18-101.4301 quality according to EN 10088 (AISI 304) shall be used. For specific
applications, stainless steel of X 5 CrNi-18-10-1.4404 quality according to EN
10088-2 (AISI 316) can be used.
C.2.02 sheet thickness
C.2.02.1 tubes
The stainless steel air ducts shall be made in a sheet thickness that is dependent
upon the diameter, as specified below. Based on the diameter, the following apply
as minimum sheet thicknesses in standard implementations:
C.2.02.2 fittings
Stainless steel fittings shall be made in a minimum sheet thickness of 0.6 mm.
C.2.03 joints in tubes
The joints in the spiral-wound strip shall be made as a flat folded seam, providing
sufficient rigidity and airtightness.
C.2.04 joints in fittings
The seam joints in fittings shall be made in such a way that sufficient rigidity and
airtightness are obtained. These joints shall be made by welding or folding.
C.2.05 tube length
Tubes shall be supplied in standard lengths of 3000 or 6000 mm. For technical
reasons, tube lengths shall in principle be not less than the tube diameter, with a
minimum length of 300 mm.
C.2.06 diameters
The tubes shall be made in standard diameters according to EN 1506, namely 63 80 - 100 - 125 - 160 - 200 - 250 - 315 - 400 - 500 - 630 - 800 - 1000 and 1250
mm. Additional sizes stated in EN 1506 are: 150 - 300 - 355 - 450 - 560 - 710 900 - 1120 mm.
C.2.07 bends
With the exception of diameters of 63 and 80 mm, for which the curve radius shall
be 100 mm, the shape of bends shall normally be determined by a radius,
measured across the centre of the bend, that is equal to the tube diameter.
Standard bends shall have angles of 15°, 30°, 45°, 60° and 90° in segmented
construction with a tolerance of ±2°. Segmented bends of 45° shall consist of at
least 3 segments.
C.2.08 reducing couplings
Reducing couplings may be either symmetrical or asymmetrical, with an upper
angle of minimum 15° and maximum 60°. Pressed reducing couplings may have a
maximum upper angle of 90°. Symmetrical reducing couplings shall be used as
standard.
C.2.09 branches
A branch (a take-off in an ongoing section of main duct) can be made
by means of a:



saddle piece, in combination with a straight tube;
T-piece, as a complete fitting;
4-way coupling, as a complete fitting;
and can be implemented as standard at an angle of 90° or 45°.
For technical reasons, angles < 45° should be avoided.
C.2.10 forks
A fork is a subdivision of a main duct into two ongoing ducts.
It can be made by means of a:


breech (Y-piece);
inverted T-piece.
If a breech is used, the fork can be made at an angle α = 90° or 60°.
If an inverted T-piece is used, the fork can be made at an angle α =
180°.
C.2.11 coupling pieces
These are used as standard in:


joints between adjacent tubes; This fitting, made of the same
material as the tubes and provided with a buffer edge, creates an
internal joint. .
joints between adjacent fittings; This fitting, made of the same
material as the tubes, is of smooth construction and creates an
external joint.
The insert length of the fittings shall be based on EN 1506.
For overlaps, the following minimum lengths shall apply:
The joints shall be fixed using self-tapping screws and finished with:






tape with synthetic rubber mass (= self-vulcanising shrink tape);
PVC tape: only for exhaust ducts;
aluminium tape: only for exhaust ducts;
linen tape: only for exhaust ducts;
reinforced PE tape with acrylic adhesive mass;;
2-component strip.
These tapes must be applied in accordance with the supplier’s
recommendations.
When round fittings with a rubber seal (so-called “Safe”) are used,
the finishing with tape shall normally be omitted in the case of onceonly installation.
C.2.12 adjustable dampers
Adjustable dampers serve for the regulation of an installation and
shall be made manually adjustable. They shall be provided with a
reliable securing device, which also shows the damper setting. For
surface areas up to 0.3 m2, the damper blade, made of the same
material as the air duct, shall be made of single-thickness sheet.
The dampers shall be provided with reliable and airtight bearings.
Perforated damper blades should be avoided.
C.2.13 end covers
Covers shall be made of the same material as the tubes.
C.2.14 tolerances
The maximum tolerance for the length of a duct is ±0.005 x L.
The tolerance for the diameters is specified in the adjacent table.
The maximum tolerance for angles is ±2°.
D.1.00 Rectangular plastic ducts
D.1.01 sheet quality
Durable and reliable air ducts are essential. Plastics score well in terms of these 2
criteria, and are therefore also highly suitable for ventilation applications.
The following plastics are appropriate for the manufacture of air ducts: PVC, PVC-C,
HDPE, PP and PP-S. These plastics are chemical- and corrosion-resistant. They are
therefore also appropriate for the extraction of aggressive vapours and steam. In
addition, they are maintenance-free and guarantee long life.
PVCPVC is highly suitable for corrosive and aggressive conditions. It is processed by
means of glue bonding or hot gas welding.
PVC-C: PVC-C has high chemical resistance and a better temperature resistance than
PVC. It is usually processed by means of glue bonding.
HDPE: HDPE is an inert material that is highly resistant to abrasive and corrosive
substances. HDPE has a very smooth surface and is fairly impact-resistant. It is
usually processed by means of welding.
PP en PP-S: The PP tubing for industrial purposes is supplied in a light grey-beige
colour RAL 7032. Thin-wall PP tubes are used for low-pressure ventilation
applications. PP-S is a low-combustibility polypropylene with self-extinguishing
properties. The colour of these tubes is grey RAL 7037.
These plastics are usually processed by means of welding.
D.1.02 wall thickness
Plastic air ducts shall be made in a wall thickness that is dependent upon the largest
duct side, as specified below. The air ducts shall be manufactured at this thickness to
ensure sufficient rigidity against distortion. Based on the largest duct side, the
following apply as minimum wall thicknesses:
D.1.03 joints
The various plastics shall be joined in the following ways:





PVC: glue bonded, welded or mechanically joined;
PVC-C: glue bonded or mechanically joined;
HDPE: welded or mechanically joined;
PP: welded or mechanically joined;
PP-S: welded or mechanically joined.
D.1.04 transverse joints
Transverse joints in adjacent air ducts shall be made by means of flanges formed from
strip material or angle sections. The flanges shall be securely fastened to the ducts.
The quality and thickness shall satisfy the same requirements as the material from
which the duct is manufactured. Adjacent sections shall be connected with fasteners
and sealing tape that are sufficiently chemical-resistant and provide sufficient
airtightness. In all cases, transverse joints that are made internally by means of
coupling pieces shall be welded. External coupling pieces shall always be welded if PP
or HDPE is used, and shall also be glue bonded if PVC-C is used. If the duct side is
600 mm or greater, internal reinforcements shall also be fitted. Adjacent transverse
joints shall be welded using expansion sleeves of soft PVC.
D.1.05 longitudinal joints
In principle, longitudinal joints between duct sections shall be welded.
D.1.06 reinforcements
Air ducts shall be made with a rigidity sufficient to prevent distortion. Assuming that
the recommended minimum wall thickness according to D.1.02 is used, duct surfaces
and duct sections with a width > 300m shall be reinforced. For ducts with a width >
600 mm, surfaces with an area greater than 1 m2 shall be additionally reinforced using
externally or internally welded strips, or round spacer sleeves made from plastic
conforming to the same specifications shall be fitted in the duct sections. For ducts
with a width greater than 1000 mm, surfaces with an area greater than 0.7 m2 shall
also be additionally reinforced.
D.1.07 types
For the possible types of plastic air ducts, see D.1.01. It is important that the choice of
the material is made in consultation with the supplier.
D.1.08 dimensions
The nominal dimensions of the air ducts shall be given in mm and refer to the outside
dimensions with a tolerance of ±2 mm up to and including a side length of 1000 mm.
The dimensions shall be standardised as for the dimensions of rectangular metal ducts.
D.1.09 exposed ductwork
If a section of the air duct system in an air-conditioning installation is intended as
“exposed ductwork”, it shall be constructed as the rest of the ductwork, unless
otherwise specified. When ductwork is intended as exposed ductwork, external
stickers and labelling shall be removed, while the required airtightness shall be
obtained by internal application of sealant. Additional measures in the context of
exposed ductwork are not normally included in the standard construction.
D.1.10 bends
D.1.10.1 symmetrical bends
In principle, symmetrical bends have a round shape, i.e. with an inside and an outside
radius; the inside radius shall be at least 100 mm. (For floor or wall openings where
there is no room for an inside radius, a right-angled inside bend may be used.) To limit
the friction in a bend, the bends shall be provided with vanes. Vanes are not required
in the following cases:


a bend of 45° or less;
a duct with a width of 400 mm or less.
The vanes shall be positioned according to the following table.
D.1.10.2 reducing bends
In the case of reducing bends, the smallest duct width shall determine the number of
vanes, in accordance with the above table. The ratio for the position of the vanes at the
largest duct width is then equal to the ratio for the vanes at the smallest duct width.
D.1.10.3 construction of vanes
Vanes shall be made of single-thickness sheet. The sheet material shall be the same as
that used for the duct. The construction and fastening shall be of sufficient strength.
D.1.11 reducing couplings
Reducing couplings shall be made in such a way that the upper angle α may in
principle be 60° maximum.
D.1.12 branches
A branch (a take-off in an ongoing section of main duct) can be made by means of a
streamlined fitting, either rectangular or round. Technical aspects of air flow design
co-determine the type, as shown in the drawings below.
D.1.13 forks
A fork is a subdivision of a main duct into two ongoing ducts.
Examples of forks are:
D.1.14 adjustable dampers
Adjustable dampers serve for the regulation of an installation and shall be made manually adjustable. They shall be provided with a reliable securing device, which
damper setting. The damper blade, made of the same material as the air duct, shall be made of single-thickness sheet with a thickness of at least 4 mm, a maximum
400 mm and a maximum surface area of 0.20 m2.
D.1.15 smoke development, fire propagation and combustibility
PVC: low combustibility, self-extinguishing in accordance with DIN 4102/Class B1
PVC-C: low combustibility, self-extinguishing in accordance with DIN 4102/Class B1
HDPE: normal combustibility, non-self-extinguishing in accordance with DIN 4102/Class B2
PP: normal combustibility, non-self-extinguishing in accordance with DIN 4102/Class B2
PP-S: low combustibility, self-extinguishing in accordance with DIN 4102/Class B1
D.1.16 operating temperature
The maximum operating temperature for PVC ducts is 60ºC..
The maximum operating temperature for PVC-C ducts is 90ºC.
The maximum operating temperature for HDPE ducts is 70ºC.
The maximum operating temperature for PP ducts is 100ºC.
The maximum operating temperature for PP-S ducts is 100ºC.
D.2.00 Round plastic ducts
D.2.01 sheet quality
Durable and reliable air ducts are essential. Plastics score well in terms of these 2 criteria, and are therefore also highly suitable for ventilation applications. The fo
appropriate for the manufacture of air ducts: PVC, PVC-C, HDPE, PP and PP-S. These plastics are chemical- and corrosion-resistant. They are therefore also appr
extraction of aggressive vapours and steam. In addition, they are maintenance-free and guarantee long life.
PVC: PVC is highly suitable for corrosive and aggressive conditions. The colour of PVC tubes is grey RAL 7011. PVC is processed by means of glue bonding or
PVC-C: PVC-C has high chemical resistance and a better temperature resistance than PVC. It is usually processed by means of glue bonding.
HDPE:HDPE is an inert material that is highly resistant to abrasive and corrosive substances. HDPE has a very smooth surface and is fairly impact-resistant. It is
means of welding.
PP en PP-S:The PP tubing for industrial purposes is supplied in a light grey-beige colour RAL 7032. Thin-wall PP tubes are used for low-pressure ventilation app
low-combustibility polypropylene with self-extinguishing properties. The colour of these tubes is grey RAL 7037. These plastics are usually processed by means o
D.2.02 wall thickness
The tubes and fittings shall be made in a wall thickness that is dependent upon the diameter, with a minimum thickness of 1.8 mm.
D.2.03 joints
The various plastics shall be joined in the following ways:





PVC: glue bonded, welded or mechanically joined;
PVC-C: glue bonded or mechanically joined;
HDPE: welded or mechanically joined;
PP: welded or mechanically joined;
PP-S: welded or mechanically joined.
The fittings shall have sleeve couplings as standard.
D.2.04 tube length
To avoid difficulties in transport and handling, standard tubes shall be supplied up to a maximum length of 5000 mm with a tolerance of ±0.005 x L.
D.2.05 diameter/tolerances
D.2.06 bends
With the exception of diameters of 63 and 80 mm, for which the curve radius shall be 100 mm, the shape of bends shall normally be determined by a radius, measu
of the bend, that is equal to the tube diameter. Standard bends shall have angles of 15°, 30°, 45°, 60° and 90° in pressed or segmented construction with a tolerance
bends ≥ 45° shall consist of at least 3 segments.
D.2.07 reducing couplings
Reducing couplings may be either symmetrical or asymmetrical, with an upper angle of minimum 15° and maximum 60°. Symmetrical reducing couplings shall b
D.2.08 branches and forks
A branch (a take-off in an ongoing section of main duct) can be made by means of a T-piece, as a complete fitting, and can be implemented as standard at an angle
A fork is a subdivision of a main duct into two ongoing ducts.
Examples of branches and forks are:
D.2.09 adjustable dampers
Adjustable dampers serve for the regulation of an installation and shall be made manually adjustable. They shall be provided with a reliable securing device, which
damper setting. The damper blade, made of the same material as the air duct, shall be made of single-thickness sheet with a thickness of at least 3 mm up to a max
mm. The dampers shall be provided with reliable and airtight bearings.
D.2.10 smoke development, fire propagation and combustibility
PVC: Low combustibility, self-extinguishing in accordance with DIN 4102/Class B1
PVC-C: low combustibility, self-extinguishing in accordance with DIN 4102/Class B1
HDPE: normal combustibility, non-self-extinguishing in accordance with DIN 4102/Class B2
PP: normal combustibility, non-self-extinguishing in accordance with DIN 4102/Class B2
PP-S: low combustibility, self-extinguishing in accordance with DIN 4102/Class B1
D.2.11 operating temperature
The maximum operating temperature for PVC ducts is 60ºC.
The maximum operating temperature for PVC-C ducts is 90ºC.
The maximum operating temperature for HDPE ducts is 70ºC.
The maximum operating temperature for PP ducts is 100ºC.
The maximum operating temperature for PP-S ducts is 100ºC.
E.1.00 Rectangular mineral wool ducts
E.1.01 panel quality
Mineral wool ducts shall be made in the following minimum density:
- glass wool 78 kg/m3 with a tolerance of 5%;
- rock wool 150 kg/m3 with a tolerance of 5%.
E.1.02 panel thickness
Mineral wool air ducts shall be made in the following minimum panel thickness:



glass wool 22 mm with a tolerance of +1 mm;
glass wool 22 mm with a tolerance of +1 mm;
rock wool 20 mm with a tolerance of +1 mm.
The air ducts shall be manufactured at this thickness to ensure sufficient rigidity against distortion.
E.1.03 transverse joints
Transverse joints between adjacent air ducts shall be made:

by means of profiles formed from sheet steel of DX 51 DZ 275 MAC quality, coated on both sides with a zinc layer according to the
Sendzimir process. The layer thickness shall be 275 g/m2 for both sides, measured according to the trihedral test. Sheet quality / zinc
quality shall be in accordance with EN 10142, and tolerances shall be in accordance with EN 10143. The sheet steel profiles shall be securely
fastened to the ducts.
E.1.04 longitudinal joints
Longitudinal joints shall be made as a profiled seam, and finished with an aluminium tape with a minimum width of 75 mm in the case of
ducts with an aluminium outer layer.
E.1.05 reinforcements
Air ducts shall be made with a rigidity sufficient to prevent distortion. Assuming that the recommended minimum panel thickness
according to E.1.02 is used, duct surfaces with a width > 600 mm in the case of glass wool and > 1200 mm in the case of rock wool shall
be strengthened internally with reinforcements of galvanised material. These shall be attached to the duct surfaces using screws with
washers. The number of reinforcement profiles shall be: 1 per 0.75 m2 wall surface in the case of glass wool and 1 per 1.25 m² wall
surface in the case of rock wool.
E.1.06 dimensions
The nominal dimensions of the air ducts shall be given in mm and refer to the inside dimensions with a tolerance of +2 mm for a side
length ≤ 1200 mm, and +4 mm for a side length > 1200 mm. The dimensions shall be standardised as for the dimensions of rectangular
metal ducts.
E.1.07 types
The possible types of mineral wool air ducts are:




rock wool with cement outer layer, suitable for indoor use;
glass wool with 100-micron aluminium foil outer layer, suitable for indoor use;
glass wool with polyester outer layer, suitable for outdoor use;
glass wool with 100-micron aluminium inner facing and polyester outer layer, suitable for outdoor use.
For the use of polyester, the following specifications are applicable:
o
o
450 g/m2 glass fibre for an inside duct size < 700 mm;
- 2 x 450 g/m2 glass fibre for an inside duct size ≥ 700 mm.
E.1.08 exposed ductwork
If a section of the air duct system in an air-conditioning installation is intended as “exposed ductwork”, it shall be constructed as the rest
of the ductwork, unless otherwise specified. When ductwork is intended as exposed ductwork, external stickers and labelling shall be
removed, while the required airtightness shall be obtained by internal application of sealant. Additional measures in the context of
exposed ductwork are not normally included in the standard construction.
E.1.09 bends
Bends shall be implemented as:


bends with an angle > 45º must be provided with vanes;
right-angled bends shall be provided with vanes or air turns.
E.1.10 reducing couplings
Reducing couplings shall be made in such a way that the upper angle may in principle be 60° maximum.
E.1.11 branches
A branch (a take-off in an ongoing section of main duct) can be made by means of a straight or streamlined fitting at an angle of 90°.
Technical aspects of air flow design co-determine the type of implementation.
E.1.12 adjustable dampers
Adjustable dampers serve for the regulation of an installation and shall be made manually adjustable. They shall be provided with a
reliable securing device, which also shows the damper setting. The damper blade, made of galvanised material, shall be made of singlethickness sheet with a thickness of at least 1.5 mm up to a maximum blade width (B) of 500 mm and a maximum surface area of 0.25
m2. The edges of the damper blades shall be rounded and reinforced parallel to the axis. If the surface area is greater, different types of
dampers must be used.
E.1.13 erosion resistance
In order to guarantee resistance to erosion, the ducts shall be finished internally with baked glass fibre or aluminium, depending on the
application. The air speed at any place in the duct system must never exceed 12 m/s.
E.1.14 smoke development, fire propagation and combustibility
Mineral wool ducts must be non-combustible and must comply as a minimum with Class A2 of DIN 4102 and Class 1 NEN 6065.
Smoke-developed index ≤ 1 (smoke density negligible in accordance with NEN 6066).
E.1.15 allowable system pressure
The maximum allowable system pressure is:




for rectangular glass wool ducts with an aluminium outer layer 500 Pa;
for rectangular glass wool ducts with a polyester outer layer 750 Pa;
for octagonal glass wool ducts with a polyester outer layer 1000 Pa;
for rectangular rock wool ducts 850 Pa..
E.1.16 operating temperature
The maximum operating temperature for glass wool ducts and rock wool ducts with steel profiles is 120° C.
F.1.00 Rectangular rigid foam ducts
F.1.01 panel quality
Rigid foam air ducts shall be made from panels with a minimum density of 40 kg/m3. These panels shall have aluminium
foil with a thickness of 60 microns on one side or both sides.
F.1.02 panel thickness
Rigid foam air ducts shall be made in the minimum panel thickness of 20 mm for phenolic foam, and 20 mm for PIR foam.
The air ducts shall be manufactured at this thickness to ensure sufficient rigidity against distortion.
F.1.03 transverse joints
Transverse joints of air ducts shall be made in such a way that sufficient airtightness is obtained.
F.1.04 longitudinal joints
The ducts shall be made from a flat panel, with V grooves cut at the corner. These grooves shall be
glued. The closing sides shall be cut off at 45°, glued and finished with an aluminium tape with a
minimum width of 50 mm, and if necessary provided with e.g. joint clamps.
F.1.05 reinforcements
Air ducts shall be made with a rigidity sufficient to prevent distortion. Assuming that the minimum
panel thickness according to F.1.02 is used, duct surfaces > 700 mm shall be internally reinforced.
F.1.06 types
Some possible types of rigid foam air ducts are::





phenolic foam with aluminium outer layer and glass fibre inner facing, suitable for indoor use;
phenolic foam with aluminium outer layer and aluminium inner facing, suitable for indoor use;
phenolic foam with polyester outer layer and aluminium inner facing, suitable for outdoor use;
PIR foam with aluminium outer layer and aluminium inner facing, suitable for indoor use;
PIR foam with polyester outer layer and aluminium inner facing, suitable for outdoor use.
For the use of polyester, the following specifications are applicable:


450 g/m2 glass fibre for an inside duct size < 700 mm;
2 x 450 g/m2 glass fibre for an inside duct size ≥ 700 mm.
F.1.07 dimensions
The nominal dimensions of the air ducts shall be given in mm and refer to the inside dimensions with a
tolerance of +2 mm for a side length ≤ 1200 mm, and +4 mm for a side length > 1200 mm. The
dimensions shall be standardised as for the dimensions of rectangular metal ducts.
F.1.08 exposed ductwork
If a section of the air duct system in an air-conditioning installation is intended as “exposed ductwork”,
it shall be constructed as the rest of the ductwork, unless otherwise specified. When ductwork is
intended as exposed ductwork, external stickers and labelling shall be removed, while the required
airtightness shall be obtained by internal application of sealant. Additional measures in the context of
exposed ductwork are not normally included in the standard construction.
F.1.09 bends
Bends shall be implemented as:


bends with an angle > 45º must be provided with vanes;
right-angled bends shall be provided with vanes or air turns.
F.1.10 reducing couplings
Reducing couplings shall be made in such a way that the upper angle
α may in principle be 60° maximum.
F.1.11 branches
A branch (a take-off in an ongoing section of main duct) can be made
by means of a straight or streamlined fitting at a maximum angle of
90°. Technical aspects of air flow design co-determine the type of
implementation.
F.1.12 adjustable dampers
Adjustable dampers serve for the regulation of an installation and
shall be made manually adjustable. They shall be provided with a
reliable securing device, which also shows the damper setting. The
damper blade, made of galvanised material, shall be made of singlethickness sheet with a thickness of at least 1.5 mm up to a maximum
blade width (B) of 500 mm and a maximum surface area of 0.25 m2.
The edges of the damper blades shall be rounded and reinforced
parallel to the axis.
F.1.13 erosion resistance
In order to guarantee resistance to erosion, the ducts shall be finished
internally with baked glass fibre or aluminium, depending on the
application. The air speed at any place in the duct system must never
exceed 12 m/s.
F.1.14 allowable system pressure
The maximum allowable system pressure is 750 Pa.
F.1.15 operating temperature
The maximum operating temperature for rigid foam ducts with steel
profiles is 110° C.
G.1.00 Round flexible ducts, or hoses
G.1.01 material options
Hoses shall be available in the following materials:



aluminium;;
aluminium foil;
plastic.
G.1.02 types of flexible hoses
Hoses shall be available in three types:



non-insulated;
thermally-insulated
acoustically-insulated
G.1.03 non-insulated hose
A non-insulated hose shall have a wall made of the material specified in G.1.01 and
shall be provided with a horizontal steel spiral, covered or uncovered. The spiral can
be provided with a coating.
G.1.04 thermally insulated hose
A thermally insulated hose shall have an inner hose as specified in “non-insulated hose”. The hose shall be wrapped
with thermally insulating material, such as glass wool or rock wool. Around the insulation, an outer jacket of
reinforced aluminium polyester laminate shall be fitted, which may be provided with a steel spiral.
G.1.05 acoustically insulated hose
A spiral-reinforced inner hose of glass fibre mesh, wrapped with an acoustic material, such as glass wool or rock
wool. Around the insulation, an outer jacket of reinforced aluminium laminate or plastic foil shall be fitted, which
may be provided with a steel spiral. Between the inner hose and the insulation, a foil layer can optionally be fitted, to
prevent particles of the insulation from entering the duct.
G.1.06 length of flexible hoses
Flexible hoses shall usually be supplied in compressed form. The hose must be extended before use. After the hose
has been extended, its length must not be more than 3% shorter than the nominal length stated by the supplier. The
available lengths vary from one manufacturer to another, and shall be available in lengths from 1 m to 10 m in the
extended condition. In the compressed condition, the lengths are from 0.4 m to 3 m, depending on the type of hose.
G.1.07 diameters
The flexible ducts shall be made in standard diameters that are stated in EN 13180, see the table on the left.
G.1.08 installation instructions
For the installation of hoses, see section L.1.06.10 “installation instructions for flexible hoses”.
G.2.00 Flexible aluminium hoses
G.2.01 material quality
Flexible aluminium ducts shall be manufactured from:

aluminium strip in accordance with EN 573.
G.2.02 wall thickness
The thickness of the material is dependent upon the type of hose and the supplier.
The minimum strip thickness shall be 0.095 mm.
G.2.03 joints in flexible hoses
The joints in the spiral-wound strip shall be made as a folded seam, providing sufficient rigidity and airtightness.
G.3.00 Flexible aluminium foil hoses
G.3.01 material quality
The hose shall be composed of layers of aluminium foil and polyester foil, or aluminium polyester laminate. The
hose must comply with:

NEN 6065, minimum Class 2/fire propagation.
G.3.02 wall thickness
The thickness of the material is dependent upon the type of hose and the supplier.
G.4.00 Flexible plastic hoses
G.4.01 material quality
The hose shall be manufactured from a fibre-reinforced synthetic fabric or from a vinyl-coated woven fabric.
G.4.02 wall thickness
The thickness of the material is dependent upon the type of hose and the supplier.
H.1.00 Internal and external coating of air ducts
H.1.01 purpose of coating
The purpose of coating is to protect the ductwork. This can be
because there are aggressive substances in the air, for instance in the
case of swimming baths. The fresh air used as supply air can also
contain corrosion-promoting constituents. Coating can also take place
with the aim of simplifying internal cleaning. For instance, in the case
of mineral wool or rigid foam ducts that are used in the food industry.
H.1.02 types of coating
There are different types of coating with a variety of uses and
instructions for use.
Common types are:




water-repellent bituminous coating;
polyester coating;
polyurethane coating;
corrosion-resistant primer.
In addition to the purpose of the coating, the type used is also
determined by the nature of the air duct and the field of application.
The nature of the duct can be divided into:




rectangular mineral wool
rectangular rigid foam;
rectangular galvanised steel sheet;
round galvanised steel sheet.
H.1.03 instructions for use
The coating must be processed in accordance with the supplier’s instructions for use.
I.1.00 Thermal insulation of rectangular and round air ducts
I.1.01 internal insulation of rectangular air ducts
Internal insulation can only be used for rectangular air ducts. For round air ducts, in principle it is only possible to
use external insulation. However, to prevent contamination of the installation and other problems, it is very strongly
recommended that air ducts should only be insulated externally. If the decision is nevertheless made to insulate
rectangular ducts internally, the following materials can be used:
- glass wool or rock wool blankets with long fibres and finished with protective foil to prevent the shedding of these
fibres. The most common thicknesses are 0.5” or 1” (13 or 26 mm);
- vulcanised synthetic elastomers, usually with self-adhesive foil with a thickness of between 10 and 25 mm,
depending on the application and the manufacturer.
I.1.01.1 properties
The insulation blankets must comply with the following requirements:


non-combustible, in accordance with DIN 4102, Class 2 and fire propagation in accordance with NEN 6065, Class 1;
smoke-developed index: ≤1 (smoke density negligible in accordance with NEN 6066).
I.1.01.2 processing of insulation blankets without self-adhesive foil
The insulation blankets shall be glued into the duct with contact adhesive. The entire duct surface shall be glued
using a roller or using spray adhesive. The contact adhesive can be used at a temperature of approx. 15° C. The duct
wall must be dry, clean and grease-free to obtain good adhesion. For extra fastening, at least 2 self-stick insulation
anchors, weld pins or split-pin insulation anchors with cover plate for each m2 of wall surface area must be fitted on
the walls of the duct.
I.1.01.3 finishing
On the end edges of the duct, the insulation must be finished with galvanised sheet profiles or plastic profiles. This is
to prevent the shedding of insulation after duct sections have been joined together.
I.1.02 external insulation of rectangular and round air ducts
External insulation can be classified into three sections:
1. thermal insulation using glass wool or rock wool blankets (see I.1.03);
2. thermal insulation using plastic foam rubber on the basis of synthetic rubber (elastomer) (see I.1.04);
3. thermal insulation using glass wool or rock wool blankets, finished with aluminium cladding (see I.1.05).
I.1.03 het thermisch isoleren met behulp van glaswol- of steenwoldekens
This type of insulation shall only be used indoors. Rectangular and round metal air ducts shall usually, depending on
the application, be externally thermally insulated using robust glass wool or rock wool blankets with a thickness of
25 mm. These blankets are composed of upright fibres, the so-called lamella blanket, covered on one side with a foil
of reinforced pure aluminium (thickness 0.02 mm). Lamella blankets are available with and without a self-adhesive
foil. For rectangular ducts, the insulation shall be fitted against the insulation strip and finished on the suspension
structure. The bracket that is used for round ducts shall be incorporated within the insulation. The suspension
structure for rectangular ducts is then outside the insulation. For this purpose, an equivalent high-compression
insulation strip shall be fitted between the suspension structure and the duct wall, and the seams shall be provided
with a vapour-tight finish. There is also the possibility of placing the air ducts on MDF blocks with the same
thickness as the insulation. In that case, however, the insulation must be inserted between the blocks (see L.1.03.3).
It is also possible to insulate the air ducts before installation. When this is done, the insulation is somewhat
compressed in the suspension bracket; it must be ensured that the protective foil around the insulation does not tear.
I.1.03.1 properties
The lamella blankets must comply with the following requirements:


non-combustible, in accordance with DIN 4102, Class 2 and fire propagation in accordance with NEN 6065, Class 1;
smoke-developed index: ≤1 (smoke density negligible in accordance with NEN 6066).
I.1.03.2 processing of insulation blankets without self-adhesive foil
The insulation blanket must be cut at the following length:
For a rectangular duct:

L = 2x (duct width + 2x insulation thickness) + 2x (duct height + 2x insulation thickness) + overlap.
For a round duct:

L = (diameter of duct + 2x insulation thickness) x 3.14 + overlap.
I.1.03.3 processing of insulation blankets with self-adhesive foil
This insulation shall be used in badly ventilated spaces and, because of the absence of self-stick insulation anchors,
for rectangular ducts installed as “exposed ductwork” up to a width of 1200 mm. The insulation must be cut at the
following length:
For a rectangular duct:

L = 2x (duct width + 2x insulation thickness) + 2x (duct height + 2x insulation thickness) + overlap.
For a round duct:

L = (diameter of duct + 2x insulation thickness) x 3.14 + overlap.
I.1.03.4 sticking and finishing for rectangular ducts (without foil)
The lamella blankets shall be glued to the duct with contact adhesive. The entire duct surface shall be glued using a
roller or using spray adhesive. The contact adhesive can be used at a temperature higher than approx. 0° C. The duct
wall must be clean, dry and grease-free to obtain a good adhesion between the insulation and the duct wall. To
ensure that the insulation does not become detached from the duct wall while the adhesive is drying, in the case of
horizontally installed air ducts wider than 600 mm, at least 2 self-stick insulation anchors, weld pins or split-pin
insulation anchors with cover plate for each m2 of wall surface area must be fitted on the underside and the side
walls of the duct. In the case of vertically installed ducts, insulation anchors must be fitted on all walls wider than
600 mm. It is recommended that the insulation should be fitted precisely between the flange joints. If it is necessary
to insulate the flanges, due to the danger of condensation on the flange, a separate strip must be fitted over the flange
joint. The seams between the lamella blankets must be stuck together using an aluminium “all-weather" tape, with a
width of 75 mm and a minimum adhesion strength on steel of 9N/25 mm2, and then smoothed down.
I.1.03.5 sticking and finishing for rectangular ducts (with foil)
After cutting the insulation to the right size, peel off the backing over approx. 10 cm longitudinally. The insulation
must then be fitted in the right position and pressed down firmly over the entire surface area (NB: once the
insulation has been pressed down, it cannot be moved again). After this, peel off the remaining backing in stages,
and each time press the insulation down firmly against the duct wall over the entire surface area. It is recommended
that the insulation should be fitted precisely between the flange joints. If it is necessary to insulate the flanges, due to
the danger of condensation on the flange, a separate strip must be fitted over the flange joint. Ducts up to a width of
1200 mm do not need to be provided with self-stick insulation anchors, weld pins or split-pin insulation anchors.
During the processing, the surrounding temperature must be between +10° C and +50° C. The seams between the
lamella blankets must be stuck together using an aluminium “all-weather" tape, with a width of 75 mm and a
minimum adhesion strength on steel of 9N/25 mm2, and then smoothed down.
I.1.03.6 sticking and finishing for round ducts
For round air ducts, spray adhesive and/or contact adhesive shall not be used. The insulation must be cut at the right
length and the overlap prepared by cutting the insulation away from the aluminium foil. The seams must then be
stuck using the tape stated in I.1.03.5, and smoothed down. In addition, at intervals of 600 mm a pull-up strap with a
width of at least 10 mm must be fixed around the insulation.
I.1.04 thermal insulation using plastic foam rubber on the basis of synthetic rubber (elastomer)
This method of insulation shall only be used indoors. Where there are greater temperature differences (e.g. fresh air
supply ducts) or where the ducts are “exposed”, rectangular and round metal ducts shall be externally insulated using
the above-mentioned insulation material. This material is available in various thicknesses, depending on the
manufacturer and the temperature differences. This insulation material is available with and without a self-adhesive
foil. To obtain correct insulation, the suspension structures shall be kept outside the insulation, for both rectangular
and round ducts. In addition, a separate strip of the same insulation thickness shall always be glued over the duct
flanges
I.1.04.1 properties
The insulation must comply as a minimum with the following requirements:



non-combustible, in accordance with DIN 4102, Class 2 and fire propagation in accordance with NEN 6065, Class 1;
smoke-developed index: ≤1 (smoke density negligible in accordance with NEN 6066);
practical reaction to fire: self-extinguishing, non-drip and non-fire-spreading.
I.1.04.2 processing
The insulation must be cut at the following length:
For a rectangular duct:

All the sides shall be cut to the size of the side + 1x insulation thickness.
For a round duct:

L = (diameter of duct + 2x insulation thickness) x 3.14.
I.1.04.3 sticking and finishing
For both rectangular and round air ducts, the insulation shall in principle be glued over the entire surface with the
adhesive supplied with the insulation by the supplier. All buffer edges must be pressed down well, and therefore also
glued well. This also applies for use of insulation with a self-adhesive layer. The surfaces to be glued must be dustfree and grease-free. This form of insulation does not need to be further finished with tapes or self-stick insulation
anchors.
I.1.05 thermal insulation using glass wool or rock wool blankets, finished with aluminium cladding
I.1.05.1 general
For the fitting of the mineral wool blanket, see section I.1.03.
I.1.05.2 fitting of aluminium cladding
Externally insulated ducts that are located outdoors can be finished with (stucco) aluminium cladding. In coastal
areas, the seawater-resistant quality (AlMg3 / EN AW 5754) is recommended for this. After the metal air ducts have
been installed on the roof or against a wall in the open air, the external insulation of the required material and
thickness shall be fitted. After this, the aluminium cladding shall be fitted. The thickness of the aluminium panel
shall be a minimum of 0.8 mm. The cladding shall be fitted by overlapping the adjacent panels. These panels shall
be provided with so-called corrugations, which shall be made in the panel approx. 20 to 25 mm from the end of the
panel. These corrugations shall be placed on top of each other, and fastened together with at least 13 x 3 mm
stainless steel sheet-metal screws (8 screws/m). The cladding shall be fitted closely over the insulation, overlapping
and draining in such a way that rainwater cannot enter or leak in. For this purpose, all seam joints in the panelling
shall be provided with rain-tight sealing during or after installation of the aluminium cladding, using transparent
silicon sealant. In order to obtain a rigid whole (especially in the case of larger ducts), aluminium strengthening
strips can be fastened to the duct when it is being insulated. The aluminium cladding can then be fixed to these
strips. If this is done, care must be taken that the aluminium strips are not fastened directly to the steel, because of
the danger of electrolytic corrosion. A solution for this is to apply sealant, paint or tape between the duct and the
strengthening strip.
J.1.00 Fire-resistant insulation and sheathing of metal air ducts
J.1.01 air ducts and fire compartments
Fire compartments can be classified into:


fire compartments;
smoke compartments.
J.1.01.1 fire compartments
Air duct systems must comply with fire compartment requirements, as set down in the Dutch Buildings Decree (Bouwbesluit). When an
air duct passes through a fire compartment, a fire damper must be used, which as a minimum is equal to the fire resistance of the partition
in which it is located. Fusible links of the fire damper must be accessible by means of an inspection hatch or a removable servicing block.
To prevent fire transfer via ventilation ducts, air ducts must be constructed in a fire-resistant manner, or a fire damper must be fitted at the
position of a penetration of the partitioning construction. If it is not possible to fit fire dampers at the position of the penetration, the air
duct section from the partitioning construction to the partition of the fire damper blade must be constructed in a fire-resistant manner, with
a fire resistance equal to that of the partition concerned. The fire resistance of a fire damper must be demonstrated with a certificate of an
accredited body.
The following test methods are applicable for this:


for fire-resistant ducts without fire dampers, in accordance with EN 1366-1 (NEN 6076);
for fire-resistant ducts with fire dampers, in accordance with EN 1366-2 (NEN 6077).
Identification and use of the correct standards
The various suppliers offer products that have been approved in accordance with various standards. First of all, it is essential to always
look at whether they say ‘tested in accordance with’ or ‘approved in accordance with’. Both terms are found in the market, while only the
latter is at all meaningful. Suppliers of fire dampers, intumescent grilles and fire-resistant sleeves say that they conform to different
standards, both NEN and EN. An explanation is given below of how this situation has arisen, and which standards are applicable.
NEN standards
Until a few years ago, in the Netherlands only the NEN standards were used, in particular:


NEN 6069: Testing and classification of resistance to fire of building products and building elements;
NEN 6077: Experimental determination of the fire resistance of ventilation ducts with dampers.
Without quoting the texts of the standards in full, the following conclusions can be stated:
NEN 6069: This standard covers the testing of e.g. intumescent grilles. Products that have been approved in accordance with this standard
were tested in a non-pressure situation. An intumescent grille of this kind may then be used in e.g. a door or wall as an overflow provision.
It is only permissible to use this product in air ducts if it is certain that the air-conditioning installation will switch off in the event of fire,
guaranteeing that the intumescent grille will not be placed under pressure during a fire. After all, the product has not been tested for this,
and therefore not approved. It should also be noted here that in the Netherlands in most cases the air-conditioning installation is used to
remove smoke in the event of fire (to keep escape routes clear), which means that it is only permissible to use an intumescent grille in an
air duct in a small number of cases.
NEN 6077: This standard covers the testing of fire dampers. Fire dampers that comply with this standard were tested and approved under
pressure, i.e. they may be used in air-conditioning installations without additional conditions being imposed.
NEN-EN standards
For some time, European standards have also been applicable, abbreviated as EN. In connection with fire-resistant products for airconditioning installations, EN 1366 is the most important standard. Given the European character, fire-resistant products no longer need to
be tested in each country, even though the different countries take a different approach to the fire safety of installations. If a test laboratory
is equipped to test in accordance with EN 1363-1 (the standard that gives the general requirements for the methods and equipment for
conducting the test), it may conduct just one test to cover all European countries. A classification is then given on the basis of EN 13501-3
for ventilation products. The test leads to a test report, and on the basis of this a classification report is produced. In view of the above, it is
therefore important that a supplier of fire-resistant products can provide the classification report, rather than the test report. After all, this
contains the conclusion as to whether, and if so for how many minutes (15, 20, 30, 45, 60, 90, 120, 180, 240 or 360 minutes) the product
concerned has been approved. This is always shown with: EIS xx, where xx is the number of minutes. The E stands for integrity, the I for
insulation and the S for smoke leakage. For instance, EIS 60 indicates that the product concerned prevented the spread of smoke and
insulated against heat, i.e. prevented it from spreading, for at least 60 minutes.
EN 1366 makes the same distinction as the above-discussed NEN standards:
EN 1366-2: approval in accordance with this standard means that the product concerned was tested and approved under pressure. This is
therefore the standard with which fire dampers tested after the ‘NEN era’ must ideally comply. EN 1366-3: a product with this approval
was not tested under pressure, so has only be approved as e.g. an overflow provision between rooms. But definitely not for use in air ducts
where it is not guaranteed that the air-conditioning installation will switch off in the event of fire.
Conclusions and advice
You should make sure that you use approved products, and not merely tested products. Then assess whether you only require a fireresistant provision in a non-pressure situation (the applicable old standard is NEN 6069, new standard is EN 1366-3); or if the situation
involves pressure, then a product approved in accordance with the old standard NEN 6077 or the new standard EN 1366-2 must be used.t
J.1.01.2 smoke compartments
When an air duct passes through a smoke compartment, a fire damper
must be used or the duct section that goes through this partition must
be constructed over a distance of at least 3 metres without a break and
without apertures (grilles). The 3 metres can be shifted in relation to
the smoke partition.
J.1.02 fire-resistant insulation of round air ducts
If high fire-resistance requirements are imposed on the air flow path,
it is recommended that rectangular air ducts should be constructed,
in connection with the use of certified insulation materials.
There is a product available in the trade, which is supplied with a
thickness of 60 mm and, depending on the compression (weight per
m2 of panel surface area), can be used for a 60-minute, 90-minute or
120-minute fire partition wall. Equivalent products can also be used,
if a valid test report can be provided.
J.1.03 fire-resistant insulation of rectangular air ducts
For this, the following insulation materials in the recommended
thickness and type can be used:


The insulation materials (fire boards) shall be fitted directly onto
the air duct in accordance with the supplier’s instructions. These
boards shall usually be fixed using weld pins or screws. The boards
shall be fastened to each other with a special type of adhesive.
Non-combustible fibre silicate boards.
Asbestos-free boards, manufactured from fibres, Portland cement
and fillers, must be fitted in accordance with the manufacturer’s
instructions.
J.1.04 suspension of fire-resistant insulated air ducts
Ducts must in principle be suspended as in the test method used in the
standard.
As a general guide, the following recommendations are made for this:




maximum distance between the suspensions centre-to-centre 1.5
m;
maximum weight per suspension point 50 kg;
maximum allowable stress in threaded rods 9N/mm2 with a fire
resistance of 30 and 60 minutes;
maximum allowable stress in threaded rods 6 N/mm2 with a fire
resistance of 90 and 120 minutes.
Suspensions must be made so that the duct is fully clamped, by means
of an upper bracket and lower bracket, and suspended by means of
threaded rods of minimum M6 in metal plugs. This applies for both
rectangular and round air ducts.
J.1.05 fire-resistant penetrations
The test method for partitioning constructions with penetrations is laid down in the
standards NEN 6069 and EN 1366-3. The finishing of penetrations can be done by:



filling with structural material (e.g. mortar or plasterboard);
filling with high-compression rock wool in combination with fire-resistant coating;
filling with rock wool.
The way in which the penetrations are finished depends on:




material, shape and dimensions (diameter, wall thickness) of the air ducts;
penetration sealing system;
additional protection, such as intumescent coating, fire sleeves etc.;
special fire-resistant sleeves that close the aperture by intumescence.
Given that penetrations of several technical installations are combined at the position of the
smoke and fire compartments, it is preferable to have this work done in combination by
specialist companies. The co-ordination and responsibility should preferably lie with a
construction partner.
J.1.06 installation of fire dampers
The installation of fire dampers must be done in accordance with the manufacturer’s
instructions. When constructing a building, it is sometimes not possible to install the fire
damper partially within the fire partition. If the fire damper cannot be installed in the fire
partition wall, the duct section between the fire partition wall and the fire damper must be
insulated in such a way that the quality of the fire partition is maintained. This shall
preferably be done under the responsibility of the construction contractor.
K.1.00 Internal cleaning of air ducts
K.1.01 general
Air ducts must be transported carefully, to ensure that they remain as clean as possible. For
the transport of round fittings, the use of packing material is recommended. At the
construction site, ducts can be stored either in the open air or in the rough building structure.
In both cases, the ducts must be stored on a dry base. It is recommended that the ducts
should be protected against extreme weather conditions and contamination. While
processing the ducts before and during installation, loose contaminants, such as dust, sand
etc., in and on the duct shall be removed before the ducts are put in position. During the
construction process, it is not possible for the air duct installation company to guarantee the
internal cleanliness of the air ducts, for practical reasons.
K.1.02 internal cleaning after the construction process has ended
Within the scope of the environmental legislation, for the healthcare sector or for special
production techniques, the requirement can be stated in the specifications that after the duct
systems have been installed (preferably after the construction process has ended), they must
be internally cleaned and provided with full certification. For this purpose, specialist
companies have effective cleaning equipment and methods for testing and measuring in
order to achieve the required level of cleanliness and to confirm this by means of a
certificate..
It can also be advisable to clean the ducts after they have been in use for a number of years,
or immediately after a fire (for instance, in relation to smoke). Given that Luka members do
not have the required equipment and knowledge, this cleaning work is not normally included
in their activities. In order to make the ducts accessible for the cleaning equipment, it is the
responsibility of the consultant or the installation contractor to indicate on the air duct
drawing the locations and dimensions of the inspection hatches or access hatches that are to
be fitted. If these provisions are not indicated on the drawing, the fitting of these is not
included in the standard activities of the air duct manufacturer.
K.1.03 The Netherlands Association of Air-conditioning System Cleaning Specialists
(Nederlands Verbond Reinigingsspecialisten Luchtbehandelingssystemen, NVRL)
In conjunction with TÜV Rheinland Nederland BV Bouw & Ondergrond (construction and
foundations), the NVRL has developed a quality mark for the cleaning of air-conditioning
systems. The quality mark is aimed at ensuring that air-conditioning systems and air ducts
are kept clean, in order to restrict as far as possible the health risks due to contamination in
these systems.
The NVRL can be found at www.nvrl.nl
L.1.00 Installation instructions
L.1.01 general
These installation instructions comply with the requirements of EN 1505, 1506 and 1507. Within the
scope of the contract between Luka and TÜV Rheinland Nederland BV Certification, the instruction to
check the manufacturing quality and installation quality has been given by TÜV Rheinland Nederland
BV Certification to TÜV Rheinland Nederland BV. Safety, health and the environment are also
important subjects in relation to installation activities. In accordance with the Working Conditions Act
(Arbowet) and the Safety, Health & Environment Checklist for Contractors (VCA), the various parties
involved in a construction project have their own specific responsibilities. For instance, the main
contractor bears the final responsibility for the safety at the project and for providing general facilities
and safety arrangements.
The Luka members, as subcontractors, bear the responsibility for, among other things, the correct
conduct of their employees and for providing them with the correct equipment. All this is usually set
down in a project plan. The Luka members provide the principal or main contractor with their own
company-specific project plan. This plan serves as part of the total project plan that will be formulated
by the main contractor.
Some important subjects in the project plan are:
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Toolbox meetings and instruction of employees.
Fitters must have a valid VCA diploma.
The use and availability of PPE (Personal Protective Equipment).
Supervision at the site, including workplace safety inspections.
The separation and orderly removal of waste.
Use of approved tools and equipment.
Safety, Health & Environment (SHE) co-ordinator.
The Luka members have their own company-specific safety or Occupational Health & Safety (OHS)
system. In many cases, this system will be combined with the environmental management system and
the quality assurance system.
L.1.02 transport and storage
Air ducts must be transported in a responsible manner, in such a way that transit damage is prevented.
For the transport of round fittings, the use of boxes, net bags, bundles, crates or containers is
recommended..
Air ducts are liable to distortion if handled carelessly or roughly. It is therefore essential to unload them
with great care. Damage to joint profiles of rectangular ducts and to the edges of round ducts increases
the likelihood of air leakage. To prevent damage as much as possible, it is recommended that the timing
of the deliveries to the construction site should be closely co-ordinated with the progress of the
installation.
At the construction site, ducts can be stored either in the open air or in the rough building structure. In
both cases, the ducts must be stored on a dry base. If they are stored in the open air, it is recommended
that the ducts should be protected against extreme weather conditions and contamination. It is desirable
that the air ducts and fittings, after being delivered to the construction site, should be stored as close as
possible to the installation location, using a crane or builder’s hoist to move them.
L.1.03 installation instructions for rectangular and round air ducts
At the start of each installation project, the lead fitter must have the installation drawings and/or material
lists in his possession. The head of the installation team must also explain the installation instructions
and the specific instructions applicable for the construction site.
L.1.03.1 suspension and support of non-insulated rectangular metal ducts
The air ducts shall be fastened or suspended in such a way that the duct sections and their accessories
form a stable and rigid whole. The choice of materials and type of structure shall take account of the
environmental conditions and the linear expansions of the duct material.
The most frequently used structures are:
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consoles, galvanised or at least finished with zinc dust paint, used for attachment to structural fastening
points;
suspension structures that are strong enough to transfer the total weight of the air ducts, including the
interposed accessories, to the structural suspension points via threaded rods;
duct angle hangers with rubber insert.
The suspension structure must be composed of a lower bracket made of Sendzimir galvanised material,
provided with felt or P.E. tape with minimum dimensions of 18 x 4 mm, with threaded rods of at least
M6 size mounted directly adjacent to the duct. The distance between these threaded rods shall be
maximum 100 mm and minimum 30 mm greater than the duct width. The brackets shall have a
maximum centre-to-centre distance between them of 3 m and can be made in either a formed profile or a
standard trade profile that is strong enough to provide sufficient rigidity. (see table below)
For shaft ducts, it is possible to use either consoles against the wall or profiles on the ducts, which are
supported on the floor. The steel structures shall be made corrosion-resistant as a minimum. Roof ducts
shall rest, by means of weather-resistant support profiles, on the roof provisions fitted by the
construction contractor. These supports shall longitudinally have a maximum centre-to-centre distance of
2.5 m between them.
L.1.03.2 suspension and support of rectangular plastic, mineral wool and rigid foam ducts
Rectangular air ducts shall be fastened or suspended in such a way that the duct sections and their
accessories form a stable and rigid whole. The choice of materials and type of structure shall take
account of the environmental conditions and the linear expansions of the duct material.
The most frequently used structures are:
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consoles, galvanised or at least finished with zinc dust paint, used for attachment to structural fastening
points;
suspension structures that are strong enough to transfer the total weight of the air ducts, including the
interposed accessories, to the structural suspension points via threaded rods.
The suspension structure must be composed of an upper bracket and lower bracket with threaded rods of
at least M6 size mounted directly adjacent to the duct. The distance between these threaded rods shall be
maximum 100 mm and minimum 30 mm greater than the duct width. The brackets shall have a
maximum centre-to-centre distance between them of 3 m and must be made in either a formed profile or
a standard trade profile that is strong enough to provide sufficient rigidity (see table in L.1.03.1). For
shaft ducts, it is possible to use either consoles against the wall or profiles on the ducts, which are
supported on the floor. The steel structures shall be made corrosion-resistant as a minimum. Roof ducts
shall rest, by means of weather-resistant or aluminium (AlMg3) support profiles, on the roof provisions
fitted by the construction contractor. These supports shall longitudinally have a maximum centre-tocentre distance of 2.5 m between them.
Installation examples of non-insulated rectangular ducts
L.1.03.3 suspension and support of insulated rectangular ductwork
If the ducts are to be externally insulated after installation, MDF
spacer blocks of 50 x 50 x 25 mm or high-compression insulation
strips of 100 x 25 mm must be fitted between the lower bracket and
the duct.
This does not apply if the ducts are insulated before installation (socalled pre-insulation).
Installation examples of insulated rectangular ductwork
L.1.03.4 suspension and support of round metal ducts
Round air ducts shall be fastened or suspended in such a way that the duct sections and their
accessories form a stable and rigid whole. The choice of materials and type of structure shall take
account of the environmental conditions and the linear expansions of the duct material. The most
frequently used structures are:
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consoles, galvanised or at least finished with zinc dust paint, used for attachment to structural
fastening points;;
suspension structures that are strong enough to transfer the total weight of the air ducts, including
the interposed accessories, to the structural suspension points via threaded rods.
The brackets for tubes with a diameter ≥ 500 mm must be executed as two-point suspension with an
upper bracket and lower bracket. Felt or P.E. tape with minimum dimensions of 18 x 4 mm must be
used between the bracket and the air duct. For smaller diameters, it is sufficient to use one-point
brackets made of Sendzimir galvanised steel strip or perforated support strapping, provided with felt
or P.E. tape, or plastic-coated perforated support strapping with one-point suspension. In addition,
standard brackets with rubber insert can be used. The maximum centre-to-centre distance between
the brackets shall be 3 m. For shaft ducts, it is possible to use either consoles against the wall or
profiles on the ducts, which are supported on the floor. The steel structures shall be made corrosionresistant as a minimum. Roof ducts shall rest, by means of weather-resistant support profiles, on the
roof provisions fitted by the construction contractor. These supports shall longitudinally have a
maximum centre-to-centre distance of 2.5 m between them.
L.1.03.5 suspension and support of round plastic ducts
These air ducts shall be fastened or suspended in such a way that the duct sections and their
accessories form a stable and rigid whole. The choice of materials and type of structure shall take
account of the environmental conditions and the linear expansions of the duct material.
installation examples of round ducts
L.1.04 installation instructions for ceiling grilles
Unless otherwise further specified, it shall be assumed that the ceiling structure will be in the form of
gridwork of 600 x 600 mm for the insertion of the ceiling grilles. Grilles must be supplied separately
for each room where they are to be installed, and must be provided with a code corresponding to a
location on the installation drawing. The principal must ensure that the “technical ceiling panels” are
placed in the gridwork. So-called “technical ceiling panels” are ceiling panels provided with
openings, in accordance with the size of the opening required for the grilles concerned. The air duct
company shall attach the panels to the grilles, and put the panel with grille in the gridwork at the
place shown on the installation drawing. The grille shall then be connected to the duct system by
means of a flexible hose. To prevent the surrounding ceiling panels from becoming dirty, this work
must be done before the other ceiling panels are fitted. If a grille is supplied with a modular panel of
595 x 595, the grille shall be inserted immediately in the 600 x 600 mm gridwork. If the
specifications state that the grilles must be suspended, this will normally be done by using 2
adjustable hangers (with a maximum length of 600 mm) to suspend the grille from the structural
ceiling above. If the “dropped” ceiling is not composed of a gridwork, but rather of interlocking
panels, lamella ceiling or plaster ceiling, the grilles will have to be suspended from the ceiling above
during the installation of the ceiling, by means of adjustable hangers with a maximum length of 600
mm. For reasons relating to the time schedule and the prevention of waiting times, this must be done
by third parties.
L.1.05 installation instructions for accessories
L.1.05.1 general
This section of the Quality Assurance Manual discusses the accessories that are to be interposed in
the air duct systems. The operation and purpose of these accessories within the systems will be
disregarded here: this section is mainly concerned with the installation and airtightness of the
accessories in the air duct system..
The basic principle is that if the air ducts must comply with airtightness requirements, airtightness
requirements must also be imposed on accessories that are to be interposed between them. These
airtightness requirements shall be the same as those internationally agreed in EN 1751. Accessories
that have round connections with “safe” rubber seals are preferable, because they make it possible to
more efficiently comply with airtightness requirements. For specific product-related installation
instructions, the supplier must be contacted.
The aim is that the total air flow path, between the air-conditioning unit and the grille, should comply
with the Luka quality assurance requirements.
L.1.05.2 installation instructions for rectangular accessories
Rectangular accessories must be installed in accordance with the manufacturer’s instructions. These
installation instructions must comply with the requirements of EN 1505, 1506 and 1507. The
components must be fastened or suspended in such a way that they form a stable and rigid whole
with the air ducts. This must be done with suspension structures that are strong enough to transfer the
total weight to the structural suspension points via threaded rods.
The suspension structure must be composed of a lower bracket made of Sendzimir galvanised
material (or other material if this is stated in the specifications), provided with felt or P.E. tape with
minimum dimensions of 18 x 4 mm, with threaded rods of at least M6 size mounted directly adjacent
to the accessory. The distance between the threaded rods shall be maximum 100 mm and minimum
30 mm greater than the duct width, depending on whether there is external insulation. The bracket
must be fitted at a minimum distance of 100 mm and a maximum distance of 400 mm before or after
the accessory, and must be made in either a formed profile (see adjacent table) or a standard trade
profile that is strong enough to provide sufficient rigidity.
Because the air duct flanges are not always the same as the accessory flanges, there are different
ways to connect them to each other.
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If the flanges are made of the same profiles, the corners must be provided with a bolt + nut joint
(minimum M6 x 20) and/or an overlap profile in the required length and width. Between the flanges,
a closed-cell sealing tape with minimum dimensions of 18 x 4 must be fitted, ensuring that the tape
overlaps in the corners (see A.1.03 “transverse joints”).
If the flanges are not made of the same profiles, the corners must be provided with a bolt + nut joint
(minimum M6 x 20) and screw clamps with a distance between them of maximum 400 mm. Between
the flanges, a closed-cell sealing tape with minimum dimensions of 18 x 4 must be fitted, ensuring
that the tape overlaps in the corners.
L.1.05.3 installation instructions for round accessories
There are 2 different ways to fasten the round accessories to the round air ducts:
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the accessory has a push-in flange (with or without a rubber insert or “safe” joint). The push-in part is
pushed into the spiral-wound tube and fixed with pop rivets or self-tapping screws. If a “safe” joint is
not used, the joint will have to be wrapped with an appropriate tape (see A.3.11 “coupling pieces”).
the accessory has a perpendicular flange. The flange on the accessory is fitted to a counter flange on
the air duct. Between the two flanges, a closed-cell sealing tape with minimum dimensions of 15 x 4
or permanently elastic sealant shall be applied. The flanges shall then be joined together using
minimum M6 nut bolts.
Accessories that have round connections with a “safe” joint are preferable, because they make it
possible to more efficiently comply with airtightness requirements.
L.1.05.4 transport and storage of accessories
Accessories must be transported and stored in a responsible manner, in such a way that transit
damage is prevented. Accessories are liable to distortion if handled carelessly or roughly. It is
therefore essential to unload them with great care. Damage to accessories increases the likelihood of
air leakage. It is therefore recommended that wooden (or plastic) crates, boxes or containers should
be used for their transport.
For their delivery to the air duct company, the transport and storage must take place under the
responsibility of the principal, and must be arranged by the principal. Accessories must be delivered
on time and stored carefully, close to the location where they will be installed. If they are delivered
too soon, there is a risk that they will become dirty or damaged during the construction work. If they
are delivered too late, additional costs will arise due to installation complications and a separate
instalment cycle, with the risk of air leakages.
L.1.05.5 inspection of accessories
To provide possibilities for the inspection of accessories, it is recommended that inspection hatches
should be fitted near them. However, these should only be fitted if they are stated or indicated in the
specifications or contract drawings of the air ducts.
L.1.06 accessories to be in-built in ducts
L.1.06.1 fire dampers
material quality
Fire dampers are normally made from the following materials:
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casing: Sendzimir galvanised steel or Promatect H;
damper blade: fire-retardant and thermally insulating material..
Other material, depending on the application, in consultation with the supplier. A fire damper must
comply with NEN 6077 and/or EN 1366-2.
joints
Rectangular fire dampers must have a flanged edge, so that this can be securely joined with the air
duct system. Round fire dampers can have either a push-in flange or a flanged edge. If reducing
couplings are needed for this, see the section “air ducts” for the types of these.
dimensions
The dimensions are standardised according to EN 1505 and 1506, and can be selected as indicated in
the table of standard dimensions shown in this Manual in sections A1.06 and A3.06. The nominal
dimensions of the fire dampers have a tolerance of +0 to -5 mm. Fire dampers must be selected
within the nominal speeds for the nett cross-section dimensions of the dampers.
inspection possibilities
It must be possible at all times to inspect fire dampers with regard to their functioning and the
damper setting (it is usually possible to check this from the outside). To check for contamination,
there must be an inspection hatch near or integrated within the fire damper (preferably on the controls
side). (see L.1.05.5)
installation instructions
For the installation of fire dampers between air ducts, see the section “installation instructions for
accessories”. For the installation location of fire dampers in the wall, the correct position is shown in
the drawings below. If this is not possible, the fire damper must be placed as close as possible to the
fire-resisting wall. The duct section between the damper blade and the fire-resisting wall will then
have to be provided with fire-resistant insulation. (see J.1.06)
L.1.06.2 damper registers
material quality
Damper registers are normally made from the following materials:
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casing: Sendzimir galvanised steel or aluminium.
Other material, depending on the application, in consultation with the supplier.
joints
Damper registers must have a flanged edge, so that this can be securely joined with the air duct
system. If reducing couplings are needed for this, see the section “air ducts” for the types of these.
typesg
The damper register can be of either parallel-rotating or contra-rotating type.
dimensions
The dimensions are standardised according to EN 1505 and can be selected as indicated in the table
of standard dimensions shown in this Manual in section A1.06. The nominal dimensions of the
damper registers have a tolerance of +0 to -5 mm.
inspection possibilities
It must be possible at all times to inspect damper registers with regard to their functioning and the
damper setting (it is usually possible to check this from the outside). To check for contamination,
there must be an inspection hatch near the accessory. (see L.1.05.5)
installation instructions
For the installation of damper registers between air ducts, see the section “installation instructions for
accessories”.
L.1.06.3 variable and constant air volume VAV and CAV regulators
material quality
VAV and CAV regulators are normally made from the following materials:
- casing: Sendzimir galvanised steel.
Other material, depending on the application, in consultation with the supplier.
joints
Rectangular VAV and CAV regulators must have a flanged edge, so that this can be securely joined
with the air duct system. Round VAV and CAV regulators can have either a push-in joint or a
flanged edge. If reducing couplings are needed for this, see the section “air ducts” for the types of
these. To ensure that the regulator works correctly, it is recommended that a straight inflow duct
section of 3 to 5 times the height or diameter should be fitted before the inflow side of the accessory.
This must be done in accordance with the supplier’s instructions.
dimensions
The dimensions are standardised according to EN 1505 and 1506 and can be selected as indicated in
the table of standard dimensions shown in this Manual in sections A1.06 and A.3.06. The nominal
dimensions of the VAV and CAV regulators have a tolerance of +0 to -5 mm.
inspection possibilities
It must be possible at all times to inspect the VAC and CAV regulators with regard to their
functioning, damper setting and contamination. For this purpose, if necessary there must be an
inspection hatch near the VAV and CAV regulators. (see L.1.05.5)
installation instructions
For the installation of VAV and CAV regulators between air ducts, see the section “installation
instructions for accessories”.
L.1.06.4 coolers and heaters
material quality
For normal comfort ventilation, coolers and reheaters are made from the following materials:
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casing: Sendzimir galvanised steel;
lamellas: aluminium;
pipes: copper;
distributor/collector: steel or copper..
Other material, depending on the application, in consultation with the supplier.
joints
Coolers and/or heaters or reheaters must have a flanged edge, so that this can be securely joined with
the air duct system. If reducing couplings are needed for this, see the section “air ducts” for the types
of these. In order to prevent leakage or damage, drilling and suchlike must be avoided when
installing the accessory. For air volumes up to 2000 m3/h, it is most common to use built-in heaters
and coolers with round connections. These accessories can be connected more efficiently to the air
ducts and contribute to the airtightness of the air duct system if these accessories have sufficient
airtightness according to EN 1751.
For air volumes greater than 2000 m3/h, it is most common to use heaters and coolers with a drip trap
that are interposed in the air duct system (see drawing below).
dimensions
The available nominal dimensions of the interposed coolers / heaters are standardised
according to EN 1505 and can be selected as indicated in the table of standard
dimensions shown in this Manual in section A.1.06. They refer to the length, with a
tolerance of +0 to -5 mm.
The dimensions depend on the manufacturer, and with regard to the height (H) are
usually available in multiples of 30, 40 or 60 mm. The width (W) is usually available in
multiples of 50 and/or 100 mm. In order to guarantee that the accessory functions
correctly, it is recommended that the ratio (W/H) should be 4, and that there should be
an even supply of air inflow.
inspection possibilities
HIt must be possible at all times to inspect interposed coolers and/or heaters for leakage,
contamination etc. For this purpose, an inspection hatch must be incorporated in the air
ducts, immediately before and after the cooler and/or heater. (see L. 1.05.5)
installation instructions
Interposed coolers and heaters must be installed in accordance with the manufacturer’s
instructions. For the installation of the coolers / heaters between the air ducts, see also
the section “installation instructions for accessories”. In contrast to the stipulations of
that section, a suspension structure must be made at a distance of 100 - 400 mm both
before and after the cooler / heater. (see L. 1.05.2)
fitting and finishing of insulation
The insulation must be fitted in accordance with the manufacturer’s / supplier’s
instructions. Specifically in the case of fibrous material (internal insulation), seams and
suchlike must be finished in such a way that the fibre material cannot be carried along
through the air flow. In order to prevent condensation, the insulation for coolers must be
provided with a vapour-tight finish on the outside, if condensation can occur.
condensate drainage
Coolers must have a drip trap and drain pan, with a provision for condensate drainage
with inclusion of a siphon and sufficient height to compensate for the pressure
difference that occurs. The drainage pipe must also have a non-pressure drainage
provision.
transport and storage
A great deal of attention must be given to the transport. Coolers and heaters must be
transported in a responsible and emphatically careful manner, in such a way that transit
damage is prevented. It is therefore recommended that wooden crates or containers
should be used for their transport. Coolers / heaters are liable to distortion if handled
carelessly or roughly. It is therefore essential to unload them with great care. Damage to
cooling pipes increases the likelihood of leakage. To prevent damage as much as
possible, it is recommended that the timing of the delivery to the construction site
should be closely co-ordinated with the progress of the installation.
L.1.06.5 humidifiers
general
The steam humidifiers that are used shall be of either direct-steam or indirect-steam
type. The distribution manifold must be installed at an inclined angle or vertically
upright, in accordance with the manufacturer’s instructions. For the correct condensate
drainage, the pressure in the return pipe must be considerably lower than the prevailing
steam pressure.
material quality
For normal comfort ventilation, humidifiers are made from the following materials:
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casing: usually made of coated Sendzimir galvanised sheet steel with a drain pan. In
special cases, the casing shall be made of stainless steel.
distribution manifold: stainless steel.
joints
Humidifiers must have a casing with a flanged edge, so that this can be securely joined
with the air duct system. If reducing couplings are needed for this, see the section “air
ducts” for the types of these. For optimum functioning of the humidifier, see
“installation instructions” below..
dimensions
Humidifiers can usually be adapted to the existing dimensions. It is recommended that
the supplier should be consulted about the possible in-build lengths of distribution
manifolds.
inspection possibilities
It must be possible at all times to inspect a humidifier with regard to leakage,
contamination etc.. For this purpose, the humidifier must be sufficiently removable to
allow all components of the humidifier to be inspected and if necessary changed.
installation instructions
Humidifiers must be installed in accordance with the manufacturer’s instructions. For
the installation of humidifiers between the air ducts, see also the section “installation
instructions for accessories”. The humidifiers must be fitted in such a way that they
form a rigid and stable whole with the air ducts. It must be possible to install the waterside connections with electric power off. To ensure that the steam is well absorbed in
the air, a 2 m length of straight duct must be installed after the humidifier. Humidifiers
are liable to distortion if handled carelessly or roughly. It is therefore essential to unload
them with great care. To prevent damage as much as possible, it is recommended that
the timing of the delivery to the construction site should be closely co-ordinated with
the progress of the installation.
fitting and finishing of insulation
The insulation must be fitted in accordance with the manufacturer’s / supplier’s
instructions. Specifically in the case of fibrous material (internal insulation), seams and
suchlike must be finished in such a way that the fibre material cannot be carried along
through the air flow. In order to prevent condensation, the insulation for adiabatic
humidifiers must be provided with a vapour-tight finish on the outside.
condensate drainage
The humidifiers must have a drain pan, with a provision for condensate drainage with
inclusion of a siphon and sufficient height to compensate for the pressure difference that
occurs. The drainage pipe must also have a non-pressure drainage provision.
transport and storage
A great deal of attention must be given to the transport. Humidifiers must be transported
in a responsible and emphatically careful manner, in such a way that transit damage is
prevented. It is therefore recommended that wooden crates or containers should be used
for their transport. Steam humidifiers are liable to distortion if handled carelessly or
roughly. It is therefore essential to unload them with great care. Damage to cooling
pipes increases the likelihood of leakage.
L.1.06.6 filter sections
material quality
For normal comfort ventilation, filter sections are made from the following materials:
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casing: Sendzimir galvanised sheet steel, provided with an inspection hatch or door.
Other material, depending on the
application, in consultation with the
supplier.
joints
The filter section must have a casing and a flanged edge, so that this can be securely
joined with the air duct system. If reducing couplings are needed for this, see the section
“air ducts” for the types of these.
dimensions
The nominal dimensions of the filter section refer to the standard dimensions of the
filter units with a tolerance of +0 to -5 mm. The dimensions are standardised as shown
in the table below.
The length of the filter varies according to the type and construction, from 200 mm to
915 mm.
installation instructions
For the installation of filter sections, see the section “installation instructions for
accessories”.
inspection possibilities
It must be possible at all times to inspect the filter section with regard to contamination.
For this purpose, there must be, in the installed situation, a possibility to easily remove,
check and replace the filter. The degree of contamination can be measured using a
“Delta P” (differential pressure) meter.
fitting and finishing of insulation
The insulation must be fitted in accordance with the manufacturer’s / supplier’s
instructions. Specifically in the case of fibrous material (internal insulation), seams and
suchlike must be finished in such a way that the fibre material cannot be carried along
through the air flow.
L.1.06.7 inspection hatches
general
Although the Luka installation instructions recommend the installation of hatches to
provide possibilities for inspection, these should only be fitted if they are stated or
indicated in the specifications or contract drawings.
Where the specifications state that the air duct systems must be provided with
inspection hatches, the positions and dimensions of these must be indicated on the
drawing. These hatches, provided with a gasket, must be securely fastened to the duct
section, without weakening the structural execution of this section. The duct section can
also be made as a complete formed component, provided with a hatch. This duct section
can be installed between the sections of the ongoing main duct.
material quality
For normal comfort ventilation, inspection hatches must be made of the same materials
as the air ducts. An exception to this are the mineral wool and rigid foam ducts, for
which metal hatches can be used.
dimensions
The dimensions depend on the manufacturer and can, for example, be selected as
indicated in the following table for standard dimensions: The nominal dimensions of the
inspection hatches have a tolerance of +0 to -5 mm..
fitting and finishing of insulation
The insulation must be fitted in accordance with the manufacturer’s / supplier’s
instructions. Specifically in the case of fibrous material (internal insulation), seams
and suchlike must be finished in such a way that the fibre material cannot be carried
along through the air flow.
installation
Non-insulated inspection covers can be in-built or on-built in both round tube and
rectangular duct. After carefully making the correct opening in the duct, the
inspection cover must be installed in accordance with the manufacturer’s
instructions.
Insulated inspection covers are normally installed in the case of insulated ducts. After
carefully making the correct opening in the duct, a sealant must first be applied on
the underside of the inspection cover frame, before installing this on the opening that
has been made. The frame should preferably be fastened to the sheet steel duct wall
using pop rivets or self-tapping screws. The insulation on the inspection cover frame
must then be finished using aluminium tape.
L.1.06.8 measurement stations to be in-built in ducts
material quality
For normal comfort ventilation, measurement stations are made from the following
material:
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casing: Sendzimir galvanised steel or plastic PPS..
joints
Rectangular measurement stations must have a casing with a flanged edge, so that
this can be securely joined with the air duct system. If reducing couplings are needed
for this, see the section “air ducts” for the types of these. Round measurement
stations can have either a flanged edge or a push-in joint.
dimensions
The dimensions are standardised according to EN 1505 and 1506 and can be selected
as indicated in the table of standard dimensions shown in this Manual in sections
A1.06 and A.3.06. The nominal dimensions of the measurement stations have a
tolerance of +0 to -5 mm.
fitting and finishing of insulation
The insulation must be fitted in accordance with the manufacturer’s / supplier’s
instructions. Specifically in the case of fibrous material (internal insulation), seams
and suchlike must be finished in such a way that the fibre material cannot be carried
along through the air flow.
installation instructions
For the installation of measurement stations, see the section “installation instructions
for accessories”. The measurement station must be installed in such a way that the
arrow on the casing points in the direction of the air flow. This is very important for
correct functioning.
L.1.06.9 round and rectangular sound attenuators
L.1.06.9.1 round sound attenuators
Material quality
For manufacturing round sound attenuators, the following materials are used:
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
Sendzimir galvanised tube for the outer jacket and perforated Sendzimir galvanised
tube for the inner jacket (rigid attenuators);
aluminium spiral-wound flexible tube (semi-flexible attenuators);
plastic, polystyrene foam rubber (sound attenuator in duct).
wall thickness
For the Sendzimir galvanised tube, the standard implementation must have a wall
thickness as shown below. For the (semi-)flexible attenuator, the wall thickness
depends on the manufacturer.
types of sound attenuators
Round attenuators appear in general as:

The generally available types of round sound attenuators are:
rigid attenuators (both straight and in the form of a bend) Rigid attenuators consist

of a spiral-wound (or rolled sheet with longitudinal seam) outer jacket and a
perforated inner jacket with acoustic insulation material between these two
jackets, in the form of rock wool or glass wool. Between the insulation and the
perforated inner jacket, there is a cloth to prevent the fibres of the insulation
material from entering the duct. The ends of the attenuator have a push-in joint,
possibly including a rubber sealing ring or with flanges, so that the attenuator can
be securely joined with the air duct system. Depending on the application for which
the attenuator is used, it can be provided with a coulisse or core.
semi-flexible attenuators
Semi-flexible attenuators consist of an inner and outer hose made of flexible
aluminium hose, with glass wool insulation between them. Between the inner hose
and the insulation, there can optionally be a cloth to prevent the fibres of the
insulation material from entering the duct. The inner hose is perforated. The ends
have a push-in joint for direct installation in the air duct system.
length of sound attenuators
The length of a sound attenuator depends on its function in the air duct system. The
most frequently used attenuators are available in lengths of 300, 500, 600, 750, 900,
1000 and 1200 mm.
diameters
Diameters of sound attenuators are standardised according to EN 1506 and can be
selected as indicated in the table of standard dimensions shown in this Manual in
section A.3.06. The thickness of the insulation depends on the use, and is available in
25, 50 and 100 mm.
fitting and finishing of insulation
The insulation must be fitted in accordance with the manufacturer’s / supplier’s
instructions. Specifically in the case of fibrous material (internal insulation), seams
and suchlike must be finished in such a way that the fibre material cannot be carried
along through the air flow.
bends of semi-flexible sound attenuators
A minimum bend radius causes a large pressure drop, so an attempt must be made to
use the largest possible bend radius. For semi-flexible attenuators, a minimum bend
radius of R= d + 2 x the insulation thickness must be used. The suppliers advise a
minimum bend radius of 2 x the diameter (d).
Double bends must be avoided.
installation instructions
For the installation of round sound attenuators, see the section “installation
instructions for accessories”.
"guso ring"
L.1.06.9.2 rectangular sound attenuators
material quality
For manufacturing rectangular sound attenuators, the following materials are used:


outer jacket: Sendzimir galvanised sheet;
coulisses: mineral wool panels, finished to prevent the fibres from entering the air
flow.
Other material, depending on the application, in consultation with the supplier.
joints
Rectangular sound attenuators must have a flanged edge, so that this can be securely
joined with the air duct system. If reducing couplings are needed for this, see the
section “air ducts” for the types of these.
dimensions
The dimensions are standardised according to EN 1505 and can be selected as
indicated in the table of standard dimensions shown in this Manual in section A1.06.
The most frequently used standard lengths are: 500, 750, 1000, 1250, 1500 mm.
Other lengths, depending on the application, in consultation with the supplier. The
nominal dimensions of the sound attenuators have a tolerance of +0 to -5 mm.
fitting and finishing of insulation
The insulation must be fitted in accordance with the manufacturer’s / supplier’s
instructions. Specifically in the case of fibrous material (internal insulation), seams
and suchlike must be finished in such a way that the fibre material cannot be carried
along through the air flow.
inspection possibilities
It must be possible at all times to inspect the sound attenuator with regard to
contamination etc. For this purpose, there must be an inspection hatch near the sound
attenuator. (L.1.05.5)
installation instructions
For the installation of rectangular sound attenuators, see the section “installation
instructions for accessories”.
airtightness
Because a sound attenuator is regarded as an air duct, the same airtightness
requirements are applicable as for all air ducts.
L.1.06.10 flexible hoses
For the correct installation of flexible hoses, the following points for attention must
be observed.
points for attention
A brief outline is given of:








general;
shortening hoses;
making connections;
suspension points;
brackets;
bends;
connection to ducts and fittings;
static electricity.
general






fully extend the hose: if the hose is not fully extended, this results in unnecessary
loss of pressure;
never use more hose than is absolutely necessary, unless the calculation has taken
this into account;
an attempt should be made to use minimum 0.5 m to maximum 1.5 m of hose. If a
greater length must be used, the hose must be correctly suspended with brackets;
when installing the hose, ensure that no damage is caused to the hose;
damaged inner hoses must be immediately replaced;
minor damage to the outer jacket must be finished with tape (aluminium tape or
PVC tape, depending on the material of the hose).
shortening non-insulated hoses





fully extend the hose;
measure the required length and mark this point with a felt pen;
cut the material around the entire circumference between the spiral-winding;
use wire-cutters to cut through the spiral of the hose;
cut off the superfluous spiral.
shortening insulated hoses





fully extend the hose;;
measure the required length and mark this point with a felt pen;
using a sharp knife, cut through the outer jacket, the insulation material and the
inner hose;
cut the hose around the entire circumference and use wire-cutters to cut through
the spiral of the inner hose. Cut off the superfluous spiral;
trim off any superfluous insulation material using scissors.
making connections with non-insulated hoses




shorten the hose in the correct way;
push the hose at least 40 mm over the connection;
then fix the hose with a strong hose clamp;
the hose can also be fitted using a so-called “guso” ring.
However, this must be done in accordance with the suppliers’ installation
instructions.
making connections with insulated hoses







shorten the hose in the correct way;
push the insulation material and the outer jacket back a little, and stick the outer
jacket, including the insulation material, firmly and in an airtight manner to the
inner hose, using tape.
push the hose at least 40 mm over the connection;
preferably use tape with a width of at least 50 mm;
using a strong hose clamp, fix the outer jacket and the inner hose to the
connection;
use aluminium tape for pure aluminium and aluminium foil hoses, and use plastic
tape for plastic hoses;
the hose can also be fitted using a so-called “guso” ring.
However, this must be done in accordance with the suppliers’ installation
instructions.
suspension points


the maximum allowable sag of the hose between two fastening points is 50 mm
(measured in the centre);
the distance between two suspension points can vary from 1.5 to 3 m. This distance
depends on the type of hose that is used.
brackets
A hose is generally very flexible and can become distorted quite easily. Distortion
reduces the internal diameter and increases the pressure loss. When fitting brackets
(using e.g. perforated strapping), it is therefore important to ensure that the diameter
of the hose is not reduced. The hose must also be supported over at least half the
circumference.
bends of flexible hoses
According to EN 13180, the bend radius of a flexible duct must comply with R = d.
However, this minimum bend radius causes a large pressure drop, so an attempt must
be made to use the largest possible bend radius.
For flexible hoses, a minimum bend radius of R = d + 2 x the insulation thickness
should be used. The manufacturers advise a minimum bend radius of 2 x the
diameter (d). Double bends must be avoided.
connection to ducts and fittings
The connection of flexible hoses to ducts and fittings must be executed with due
care. Because many hoses are installed in a bend immediately after the connection to
the duct or fitting, it is necessary to use a supporting bracket.
If the duct connection is too “sharp”, flexible hoses can become split. When
connecting a hose to light or air fittings, the connection must be made as “direct” as
possible, while taking account of the above remarks. Too many bends in the hose
near a fitting cause the pressure loss to increase unnecessarily, and can cause noise.
A minimum bend radius gives a large pressure drop.
An attempt must therefore be made to use the largest possible bend radius with a
straight intake of 2 x the diameter (d). For flexible hoses, a minimum bend radius of
R = d + 2 x the insulation thickness should be used. The suppliers advise a minimum
bend radius of 2 x the diameter (d). Double bends must be avoided.
static electricity
In a number of situations, especially in the case of plastic hoses, it is possible that the build-up and
discharge of static electricity can cause an explosion hazard. By connecting the spiral wire of the
flexible hose to an earth wire, the build-up of static electricity can be minimised.
L.1.06.11 plenum boxes (grille plenums)
material quality
Plenum boxes for grilles can be made from metal, mineral wool, plastic or rigid foam. Plenum
boxes can be provided with internal or external insulation, depending on what is required.
wall thickness
Wall thickness of the material depends on the application and type of material.
types
There are many types of plenum boxes, depending on the use, type of grille and application. A
plenum box for e.g. a ceiling grille will normally look like the figure below. A distinction can be
made between a plenum box with a top connection and a side connection for a duct system.
The seams in the plenum box must be made airtight by applying permanently plastic sealant.
connection to ducts
Ducts are usually connected to the plenum box using a flexible hose. For this purpose, a flat saddle
piece is fitted to the box. For this, see the installation instructions for “flexible hoses”.
installation of grille plenums
There are various possibilities for installing grille plenums in e.g. a “dropped” ceiling, but this
depends on the manufacturer and type. In any case, however, the grille plenums must have
installation provisions for fastening the box (using e.g. adjustable hangers) to the structural ceiling
above.
M.1.00 Airtightness
M.1.01 general
Working closely with suppliers and manufacturers of accessories, Luka aims to restrict the
air leakage of the air flow path, and thus to reduce the energy use of the air-conditioning
installation.
The air flow path should be understood to mean:



air ducts;
accessories to be interposed between air ducts;
flexible hoses.
M.1.02 airtightness of air ducts
An air duct system is only required to be perfectly airtight in exceptional cases. For
example, a leak may be impermissible for safety reasons, e.g. if the duct carries hazardous
gases or heavily polluted air. A duct system for a ventilation and climate control installation,
which is made according to current production methods, will have a certain amount of
leakage at seams and joints. For reasons of finance and operational disruption, it is desirable
to establish the allowable amount of leakage air. Although the leakage occurs at the
transverse and longitudinal joints, especially at the corners, it is assumed that the amount of
leakage air is proportional to the surface area of the duct wall. Research has shown that the
amount of leakage air per m2 of wall surface area can be calculated as follows:
The permissible amount of leakage air is related to classes of airtightness, for which a
certain test pressure applies, derived from EN 1507 and 12237. In international practice, the
following classes are used:
Unless otherwise specified, Luka uses Class C as the airtightness requirement.
Measurements can determine whether the section of duct being tested satisfies the
requirement. In practice, after measurement with the appropriate test equipment, the degree
of leakage is immediately assessed on the basis of a graph that shows the maximum
allowable air loss for Class C airtightness for installed duct sections.
When the leakage test is performed, it shall comply with the following points:

the section to be tested has been installed, but preferably not yet provided with external
insulation;





the section to be tested has been separated in an airtight manner from the rest of the
system, together with any accessories interposed within that section, for which the test
requirements have been established;
if a total duct system, also known as the “air flow path”, is being assessed, the section to be
tested must have a surface area of minimum 10 m2 and maximum 80 m2; (depending on
the capacity of the test equipment)
the section to be tested must be kept at the test pressure for 5 minutes before the leakage
volume flow is measured;
a maximum of 1% of the total surface area of the duct project must be tested;
the deviation of the test pressure is permitted to be approx. 20 Pa.
operating principle
The leakage tester basically consists of an adjustable-speed fan, a manometer to measure the
pressure in the air duct, a calibrated air intake (venturi) and a precision inclined manometer
to measure the suction pressure in the venturi. Three different air intakes are supplied (each
with its own curve) in order to cover the entire range of the leakage tester. When the leakage
tester is connected to the duct section to be tested, the speed of the fan is adjusted so that the
required test pressure is maintained within the established margin. The amount of air lost
through leakage is sucked through the venturi of the leakage tester. From the reading shown
by the inclined manometer, the air leakage in l/s can be read off the table on the leakage
tester. The measuring instrument must be calibrated every 3 years, and must have a
measurement accuracy of ±5 %.
In addition to the leakage tester described above, a version is also available that gives a
digital reading. As a result of the long-term accuracy, calibration can take place every 5
years.
The above procedures are laid down in EN 1751, 1507 and 12237.
M.1.03 airtightness of accessories
M.1.03.1 measurement method for air leakage of accessories
In order to assess whether an accessory complies with the stated airtightness requirement,
measurements must be made. The operating principle of the measurement is basically the
same as for measuring air ducts. For the measurements on a single accessory, a standard test
fixture is required. A measurement fixture of this kind, in accordance with EN 1751, is
shown in the photograph on the left of the text.
For the Luka System Certificate, Luka members must obtain measurement reports from
accessory suppliers or information via the “Luka Accessory Register”, the “LAR”, in order
to assess whether the projected accessories comply with the stated airtightness requirement.
Measurements must be performed by a measurement institute with a quality system that
conforms to ISO 17025. The (inter)national accreditation body of this measurement institute
must be recognised and a member of the EA MLA. With regard to the recognition, see the
website of the Dutch Accreditation Council (Raad van Accreditatie: www.rva.nl/search).
The Luka members also accept the measurement reports of accessory suppliers themselves,
provided that these suppliers have a valid TÜV Rheinland Nederland BV “Meetlabel”
(measurement label).
M.1.03.2 rectangular accessories
The European standard EN 1751 provides that, for determining the allowable air leakage of
damper registers, when the actual length is ≤ 1 metre, an equivalent length of 1 metre should
be used for the length of these accessories. For practical reasons, it has been agreed between
Luka and suppliers or manufacturers that this equivalent length should be used for all
rectangular accessories, insofar as the technical execution permits and the actual length is <
1 metre. This entails that the formula for the maximum air leakage for each rectangular
accessory is: øL/acc = f.Ps0.65.(2H + 2W).L (l/s)
where:
øL/app = maximum amount of air leakage in l/s
f = leakage factor
Ps = static pressure Pa
B = width of the component in metres
H = height of the component in metres
L = length of the component in metres; L = 1 when the length of the accessory is less than 1
metre, or L = the actual length if the length is more than 1 metre.
example: calculation of the allowable air loss
For a fire damper 600 x 600 mm with L = 500 mm.
Ps = 1000 Pa
f = 0.009 (see table in section M.1.02 “airtightness of air ducts”).
This fire damper is thus permitted to leak a maximum of 1.92 l/s to the surroundings at 1000
Pa in order to comply with Airtightness Class B. On the basis of the above formula, the
maximum allowable leakage for an accessory (with a length < 1 metre) in Airtightness Class
B at the following pressures can be calculated as follows:
M.1.03.3 round accessories
For practical reasons, Luka has agreed with suppliers or manufacturers that the equivalent
length of 1 metre, as stipulated in the standard EN 1751, should also be used for all round
accessories, insofar as the technical execution permits and the actual length of the accessory
is < 1 metre. This entails that the formula for the maximum amount of air leakage for each
round accessory that complies with Airtightness Class C is:
M.1.03.4 flexible hoses
The procedure for determining the airtightness of flexible hoses is laid down in EN 13810.
M.1.03.5 determination of surface area of the duct to be tested
The table below shows how to determine the number of m2 of system surface area that must
be used in the formula for the air leakage. In the table, a length of 1000 mm is used for the
accessory, unless the actual length is greater than 1 metre. In that case, the actual length
must be filled in. (see also section 5.02 “measurement methods”)
3. Quality aspects
3.01 Quality control
The quality assurance policy within Luka is the most important aspect of the association’s policy. It must be possible for customers and principals to impose
high demands on the certainty offered by Luka members in the areas of quality, delivery reliability and compliance with specifications. Luka members are
aware that quality depends on the functioning of the organisation; quality problems are often found to have an organisational cause.
In order to satisfy the quality requirements, Luka members must “say what they do” and “do what they say”. And make this open to verification. Luka
members have a quality assurance system that complies with, or is derived from, ISO 9000.
Luka members give their personnel the opportunity to gain professional skills by means of specialist training courses, safety courses etc.. All these aspects
form the basis for independent quality assurance monitoring by TÜV Rheinland Nederland BV, which conducts the inspection and is responsible for the
airtightness measurements performed by the Luka members themselves.
TÜV Rheinland Nederland BV conducts quality inspections using a checklist based on the quality assurance standards laid down in this Quality Assurance
Manual. By regularly checking the supplied and installed products, TÜV Rheinland Nederland BV can assess whether the Luka members conform to these
standards. On the basis of these checks, TÜV Rheinland Nederland BV Certification provides annual confirmation of each Luka member’s quality assurance by
awarding an “Oorkonde TÜV Rheinland Nederland BV Product Label” certificate (see annex).
Associate members of Luka, which manufacture and/or supply accessories and wish to conduct airtightness measurements themselves, are also monitored by
TÜV Rheinland Nederland BV. The correctness of the measurement method and measurement results are checked each year, and TÜV Rheinland Nederland
BV provides confirmation of the correctness by awarding an “Oorkonde TÜV Rheinland Nederland BV Meetlabel” certificate (see annex).
3.02 Quality guarantee
The quality of the technical execution of the air ducts laid down in the section “Quality assurance standards for air
ducts” is guaranteed by means of internal and external quality assurance procedures.
In practice, air ducts often form part of a total piping network for which only a limited amount of space is available.
The design and planning departments of each Luka member, working together with the principal, can produce coordinated working drawings that guarantee an integrated duct system aligned with the manufacturing possibilities. In
addition to skilled personnel, the use of modern computer-controlled manufacturing equipment ensures constant and
optimum quality of the produced air ducts. Each of the disciplines involved in the manufacturing process closely
supervises the execution of the work, to ensure continuous compliance with the quality assurance standards.
If the air ducts are also installed by the Luka member, the installation work is performed by skilled personnel in
accordance with the requirements, i.e. the “installation instructions”, imposed in the Luka quality assurance
standards. Frequent on-site checks are conducted by installation inspectors designated by the Luka member to check
compliance with these instructions, and to prevent and/or resolve any non-conformities in relation to the coordinated plan.
Each Luka member has arranged its organisation in such a way that it operates within the spirit of the Dutch standard
for quality management (ISO 9000). In addition, external monitoring of the product quality takes place in the form
of regular checks for compliance with the quality aspects, conducted by the independent quality assurance inspectors
of TÜV Rheinland Nederland BV. Sanctions are imposed in the event of non-compliance with those standards. If a
company wishes to become a member of the Netherlands Association of Air Duct Manufacturers (Luka), a ballot is
held on the basis of the solvency and identity of the company’s organisation. The candidate’s ability to continuously
comply with the Luka quality assurance standards in terms of manufacturing facilities is also investigated. In short:
each Luka member, at its own level of scale, is a reliable construction partner that is able to guarantee a consistently
high quality of project execution.
Kortom: Luka-leden, ieder op hun niveau van omvang, zijn betrouwbare bouwpartners die garant staan voor een
constante kwalitatieve uitvoering van projecten.
3.03 External quality control by TÜV Rheinland Nederland BV
To ensure that the Luka members actually manufacture and/or install the ducts in accordance with the Luka quality
assurance standards, the association has concluded a contract with TÜV Rheinland Nederland BV. Independent
external checks are conducted by TÜV Rheinland Nederland BV, giving a guarantee that the ductwork is executed
correctly. Quality assurance inspectors of TÜV Rheinland Nederland BV regularly monitor the compliance with the
standards.
If a Luka member does not satisfy the quality assurance standards, contractually agreed sanctions, to which all Luka
members have unconditionally subscribed, can come into effect.
Through the continuous quality monitoring procedures of TÜV Rheinland Nederland BV, it is possible that Luka
will provide a “Quality Assurance Certificate” or “System Certificate” for the projects executed by its members
(see annex).
But the collaboration between Luka and TÜV Rheinland Nederland BV goes even further. If any technical issues
arise, Luka can call upon the technical knowledge, experience, measuring equipment and laboratories of TÜV
Rheinland Nederland BV in order to find a solution, by applying a theoretical approach and/or conducting practical
tests. Representatives of TÜV Rheinland Nederland BV also regularly attend the meetings of Luka’s Environment
and Technology Committee (Commissie Milieu en Techniek: CMT), and provide it with practical assistance and
advice.
3.04 Policy statement of members and
associate members of LUKA
3.05 Contract specifications
The Luka members produce and install air ducts in accordance with the Luka Quality Assurance Manual (latest version).
The added value offered by Luka members compared with other suppliers is due to the fact that, among other things, the Luka quality
is monitored and guaranteed on the basis of inspections conducted at their workplaces by TÜV Rheinland Nederland BV. This means
that the air duct customers are assured of total quality control. Through the continuous quality monitoring procedures of TÜV
Rheinland Nederland BV, Luka can provide a Quality Assurance Certificate or System Certificate for projects executed by its
members.
To ensure that the consultant not only demands but actually receives Luka quality, the contract specifications should refer explicitly to
Luka standards. However, the phrase “Supply in accordance with Luka standards” is not sufficient.
Luka advises that the following phrase should be included in the contract specifications:
“Supply and installation in accordance with the Luka Quality Assurance Manual, confirmed with a valid Luka Quality
Assurance Certificate”
If requirements are imposed on the construction and airtightness of the air flow path (including accessories), Luka advises that the
following contract specifications should be used:
All the supplied air ducts, accessories and hoses must comply with their respective EN standards.
The complete air flow path, both supply and exhaust, between the air-conditioning unit and the grilles (i.e. including grille plenums)
must be supplied and installed in accordance with the quality and execution standards laid down in the Luka Quality Assurance Manual
(latest version), in compliance with Airtightness Class B as a minimum, as described in EN 1505, 1506, 1507, 1751, 13180 and 12237.
The airtightness must be tested and demonstrated by means of a leakage test report.
The quality and execution of the air flow path must be satisfactorily demonstrated to the principal, and confirmed by means of a “Luka
System Certificate”.
This is the only way to guarantee genuine Luka quality. If higher requirements of airtightness of the duct system are imposed (e.g. for
reasons of energy saving), these must be explicitly stated in the specifications, so that the construction of the air duct system can be
adjusted accordingly.