The Certified Fire wall
Why the Firestop wall?
• Insulate and keep a fire in ONLY ONE cell of a building
• Avoid the structure and the front fall towards the outside
– Secure intervention of firefighters & emergency services
– Optimize rescues
• Meet the new insurance companies requirements
–
4h certified !
Presentation Plan
• Section I: Firewall Firebreak 4h general presentation
• Section II: Firewall Firebreak 4h detailed presentation
• Section III: Firewall Firebreak 4h CSTB Certification Test
• Section IV: Firebreak system promotion & development
• Section V: Extra part on Fire regulation
Section I
Firewall Firebreak
General Presentation
Firebreak 4h: Description
• Standard panels :
– Length: 2,50 m
– Height: 1,25 m
– Thickness: 170 mm
• Smaller panels available (for adaptation to the
wall dimensions)
• ALUZINC coating
• Less than 100 kg/m2
• Steel structure on each side
Internal Composition
• Symmetrically, successive coats of :
– Cellular glass (Foamglas)
– Plaster (Prégyfeu)
– Core in Fibro-silicate
– + bonding (special glue)
Steel sheet
in ALUZINC
Foamglas
Plaster
Fibro-silicate
Plaster
Foamglas
Steel sheet
in ALUZINC
17 cm
Main Advantages
• Light construction with a good stability
• Flexible (easy to dismantle, well adapted for the renovation)
• No foundations needed (pressure on the ground surface around
1kg/cm2 a height of 15 meters) => construction simplified, removable
and reusable
• Delivery in standard panels ready for use
• Easy erection by a steel fabricator
• 4h ISO-fire resistance attested by the approved French laboratory of
the CSTB, for a height of 15m with unlimited width
Main Advantages
• The only one fire wall system in the market (4h, 15m) certified
• Collapse towards the side of the fire, therefore no risk for firefighting
and rescue teams
• Good thermal insulation : Maximum temperature of 120 degrees on the
outer face
• Good acoustic insulation => Rw (C t r) = 43 (-1, -3) dB
• Aluzinc Benefits : aesthetics (naturally silver), excellent resistance to
corrosion, officially approved for food storage application
(according to the standard NFA 36-712-6 April 2006) : No specific
treatment or additional surface is to be added
Sustainable Advantages
• Free of fibers : Inside the wall, mineral, insulating and non
combustible materials (M0)
• Guaranteed corrosion protection against perforation
• Dry system (doesn’t require water during construction phase)
• Doesn’t emit toxic substances (gases and fumes) during normal
conditions and in case of fire
• Recyclable and environmentally inert materials
Sustainable Advantages
• Safe working conditions during erection
(light elements)
• Fast, easy and cheap installation process
• Allows less disruptive refurbishment for
existing buildings
• Possibility of re-use and relocate the wall
• Storage on pallets, less space needed,
less trucks, less fuel consumption
Scope of applications
Industry
Refurbishment /
Rehabilitation
Combustible
Materials
Warehouses
Warehousing
companies
Food storage
Refrigerating
industry
Other possible applications :
Theatres /
Concert halls
Maritime/Naval
applications
Section II
Firewall Firebreak
Detailed Presentation
Mechanism
• The wall is supported by a steel
structure on each side
• The structure doesn’t bear the wall …
but the FRAME !
• Fuse fixations : bimetallic strip joined
with tin
=> when the tin casts, the steel
structure comes off and sags on the fire.
Steps of fire expansion in a warehouse cell
• Start of fire in a cell
• Vertical fire expansion
Steps of fire expansion in a warehouse cell
• Accumulation of warm
gas under the roof
• Deformation of the frame
• Fusible connections
ensure that the link
between wall and heated
structure disappears
Steps of fire expansion in a warehouse cell
• The fire is spreading in
the burn-out cell.
• The structure collapses
on the fire.
• Fully developed fire and
failure of the heated
structure. The wall
supported by the
structure on cold side
ensures 4 hours of fire
resistance.
Steps of fire expansion in a warehouse cell
• Fire is decreasing /
Decay phase of the fire
• Protected by Firebreak,
the adjacent cell on the
cold side is safe. It is not
damaged.
Structure and fitting: Fastening systems
Fuses on 5 m x 5 m grid
Traditional endwall structures
Designed to resist wind and roof loads: manufacturer does not need to
make specific allowance for fire-resistance capability.
Layout of fuses on endwal structures
on either side
5m
5m
5m
5m
5m
5m
5m
5m
Standard design :
One fuse every 5 metres : 1 fuse for 25 square metres
Firebreak 4h: structure and assembly
Wall density
98.75 kg/m2
Structure (beams)
Special fasteners
Firebreak wall
Horizontal & vertical
joints
Floor fastening
Exceptional reliability:
4 hours / 15 metres high / unlimited width
Overall view, elevation
Standard panel
Non-standard panel, type 1
Non-standard panel, type 2
Fast elevation with two team works
Structure and assembly
Assembly method
•
•
Assembly with small mobile crane
Easy fitting (slot-in)
Approximate weight of panel
300 kg
Unlimited
width
Firebreak wall up to 15 metres high
Structure and assembly: joints
Aluzinc strip, 1 mm thick
Aluzinc facing, 1 mm thick
Steel hat-section rail, 1.2 mm thick
Palusol PM
A2 stainless steel Lag screw
TH 6 x 80
ZN steel self-tapping screw
TH 4.7 x 16
Horizontal and vertical assembly
Structure and fitting:
Floor fastening
Floor fastening
Concrete
- Generally no need to strengthen
an existing concrete slab
- “U” or flat section performs
fastening rail and levelling
functions
- Fastening on existing concrete
Levelling mortar base
(thickness as required)
Concrete floor slab
• Time savings
• Clean, dry worksite
• Lower assembly costs
Floor surface pressure around 1 kg/cm2 for partition 15
metres high
Lifting spreader supplied
Structure and fitting:
Extention through façade and roof
1m
50 cm
Façade
Roof
Section III
Firewall Firebreak
CSTB Certification test
Fitting of hat-section assembly profiles
and lag bolts
Intumescent strip and screw-down closure
sheet
Test load corresponding to height of 15 meters
Test carried out by CSTB
CSTB certification test
After 4 hours 15 minutes in standard fire conditions, only half the
thickness has been destroyed.
CSTB evaluation & test report
CSTB evaluation & rating report
II
– Findings
II.1 – Rating criteria: standard
II.1.1 – Load-bearing capacity
Duration: 240 minutes
II.1.2 – Flame and fume seal-off
Duration: 240 minutes
II.1.3 – Heat insulation
Duration: 240 minutes
II.2
– Laboratory evaluation basis
II.2.1 – Test report n° RS07-050
(self-supporting wall, load 1162 daN / ml)
Section IV
Firebreak system
Promotion &
Development
Exhibition at Batimat trade show in Paris,
November 2007
Exhibition at Expoprotection trade show
in Paris, November 2008
In recognition to its innovative characteristics, the
Firebreak Wall 4H has received a the Innovation award
Development
• Firebreak 2 hours : height 15 m
• Firebreak 1 hour : height 12,5 m
• Acoustic tests of Firebreak 4hours
• Getting European Technical
Accreditations
• Floor and ceiling firestop
=> High Buildings
Section V
Extra Part on
Fire regulation
Regulations
…require compliance with structural
fire-resistance rating criteria
Fire resistance rating criteria
• R (SF): mechanical resistance time under standard test
conditions of ISO 834 load-bearing structures
• RE or E (PF): flame and fume seal-off time partition
structures (slabs, walls)
• REI or EI (CF): heat insulation (140°C on face opposite to fire)
partition structures (slabs, walls)
Regulation and decrees
General texts
Decrees, orders, circulars
French Ministry of Ecology & Sustainable Development
• Decree of 5 August 2002 on prevention of disasters in
covered warehouses requiring authorization under item 1510
(Official Journal of 1 January 2003, page 50)
• Decree giving innovative specification of clear objectives
Measures on fire resistance of warehouses
Article 6 ( specific objectives)
“In general terms, construction measures seek to ensure that
collapse of a particular item (wall, roof, pillar, beam, etc.) does not
lead to a domino-effect collapse of the building structure as a
whole (typically the neighbouring storage cells, or the partitions
between them), and that if collapse occurs it does so within rather
than outside the initial fire zone.”
Physical data
• Survival is possible up to 80°C (or possibly 150°C for firefighters
in special clothing).
• Usual materials resist temperatures up to 500°C and beyond.
• When materials reach 500°C, the local ambient temperature is
much higher.
• Conclusion: Conditions have ceased to be life-sustaining long
before structural collapse occurs in the fire
Consequences
• Local collapse of a structure in a fire is not a catastrophe in itself
provided that we can be certain there are no people alive in the
collapse zone….
BUT
• Collapse of one item must not lead to collapse in structures not
affected (or less affected) by the fire, which may not yet have
been vacated or which may be occupied by firefighters Domino
collapse must be avoided.
In most cases, the feasibility of rescuing victims in a
building on fire depends not so much on the fire resistance
of the structure as on the risk of domino collapse.
Domino collapse, illustration
Metal racks absorbed domino collapse of the structure in prestressed concrete
Objective: inward collapse kinematics
• Metal structures usually respond well to this criteria.
• A design guide is available, based on a parametric study by
CTICM (SCMF site).
•
•
CTICM = Centre Technique et Industriel de la Construction Métallique (Steel construction
technical and industrial institute)
SCMF = Syndicat de la Construction Métallique de France (French Constructional Steelwork
Association)
« Item 1510 » storage warehouses :
compartmentalization and layout
Article 9
Storage cells should be limited in surface area to reduce the
amount of combustible material burning in the event of fire, and
prevent fire propagating from one cell to another.
Storage cells should not exceed 3,000 square metres if there is no
automatic fire extinguishing system, or 6,000 square metres if there
is an automatic fire extinguishing system.
« Item 1510 » storage warehouses :
compartmentalization and layout
Article 8
Storage warehouses should be split up into cells to reduce the
amount of combustible material burning in the event of fire.
Compartmentalization should be capable of preventing fire
propagating from one cell to another.
To meet this objective, the cells must meet the following
requirements:
• The partitions between the storage cells must have a firebreak
capability of at least two hours.
« Item 1510 » storage warehouses :
compartmentalization and layout
• The partitions must continue through the roof and extend at least
1 metre above it at this point. Either the roof must be covered
with a protective strip extending over a width of least 5 metres on
either side of the partitions, or alternatively, if warranted, a dry
standpipe may be fitted along the partitions to afford similar
protection.
• Unless the outer walls have a one-hour firebreak capability, cell
partitions must extend through the outer walls and terminate
either in a section 1 metre wide along the outer walls, or extend
for 0.50 metres beyond the outer walls.
Storage compartmentalization and layout
Fire partition walls may be arranged in any configuration with
respect to the load-bearing structure.
APSAD Regulation
Regulatory minimum
requirements can be tightened
by additional requirements
specific to insurance
companies.
APSAD Regulation
2 – Firebreak partitions
2.1 – Purpose
A firebreak partition (FBP) separates two buildings or two parts of the same building
so that fire breaking out on one side of the partition will not propagate to the other
side.
2.2 – Behaviour in fire
A firebreak partition must be rated to at least REI 240, whichever side is exposed to
the fire risk. The fire resistance of the firebreak partition must be validated by an
accredited technical inspector or by a worksite report issued by an accredited
laboratory, as appropriate. A work completion report must be submitted to the project
owner in two copies, one for the insurance company.
Validation concerns the fire resistance of load-bearing items, filling materials and the
fittings of openings and passageways through the partition.
Ouvrages séparatifs coupe-feu
Règle ARSADR15 – Edition xx 2007.0
APSAD Regulation
Firebreak partitions must extend at least 1 metre above the highest point
of an area extending 7 metres either side of the partition. (See figure
2.4.1.1.a.)
2.4.2 – Extension through outer walls
2.4.2.1 – Title pending
Firebreak partitions must extend 0.5 metres clear beyond the outer face of
an outer wall. (See figure 2.4.2.1.a.)
Top view
Partition 1 metre above highest point in this area
Figure 2.4.1.1.a – Firebreak extending above roof between two buildings
of same height
If the partition separates buildings of different heights, this requirement
applies to the higher of the two buildings. (See figure 2.4.1.1.b.)
FBP
Building A
Building B
Figure 2.4.2.1.a – Firebreak extending beyond outer wall
This requirement may be lifted if there is a strip rated to EI 120 at least 2
metres wide along the whole height of the outer wall either side of the
partition, in material rated A1 or A2s1d0, with no opening it it. (See figure
2.4.2.2.a.)
Top view
Facade
FBP
FBP
Figure 2.4.1.1.b – Firebreak extending above roof between two buildings
of different heights
This measure is to ensure that fire cannot propagate through the firebreak,
by direct action of the flames or by radiated heat, and to provide a screen
protecting firefighting personnel as they work to extinguish the fire.
Building A
Building B
Facade
Figure 2.4.2.2.a – Exception to extension through outer wall: façade with
no openings, rated EI 120, in material rated A1 or A2s1d0
APSAD Regulation
2.5.2 – Openings (unobstructed bays)
Openings in a firebreak partition must be fitted with automatically closing double doors rated EI 90 and E1 120, meeting the design and
fitting requirements specified in APSAD rule R 16. (See figures 2.5.1.a and 2.5.1.b.)
Horizontal section
FBP
Firebreak door, open
FBP
Firebreak door, closed
Figure 2.5.1.a – Double firebreak door
Bays must not be more than 3.8 metres wide or 4.4 metres high.
Door closure must be operated by means of an automatic detection system or independent type I sensor-triggers.
The materials surrounding the openings (lintels and jambs) must be strong enough to support the weight of the firebreak doors and
withstand the impacts of repeated open-close action. If the material is not strong enough (cellular concrete, for example), a special frame
must be built on which to fit the door mechanisms. (Figure 2.5.1.c.) Metal lintels are not allowed.
APSAD Regulation
Type of
partition
Fire
resistance
Selfsupporting
Load bearing
Extension through roof
Structure
materials
Openings
Ventilation
& air conditioning
ducts
Conveyors
Firebreak
partition
REI 240 or EI
180 on both
faces of
double-face
firebreak
partition.
Yes
Load borne by
means of brackets
or consoles and
sliding supports.
Load-bearing
capability allowed
for double firebreak
partition.
Extension 1 metre above
roof and A1 or A2s1d0
protective strips 5 metres
either side.
A1 or
A2s1d0
Automaticclosure
double
doors, EI 90
and E 120.
Not allowed
Compliant
with APSAD
rule R16
Regulatory
firebreak
partition
REI 120
No
requirement
Target result: no
domino collapse
and no outward
collapse of fire
outbreak cell.
Extension 1 metre above
roof. Extension 0.5
metres beyond façade or
1 metre along façade on
either side. Roof covered
with protective strip 5
metres either side
No
requirement
Automaticclosure
doors,
EI 120
EI 120
EI 120
Ordinary
partition
REI 120
No
requirement
Load-bearing by
sliding supports or
fuse links.
As firebreak partition,
except for concrete roofs
A1 or
A2s1d0.
”Fragile”
faces not
allowed if
rack parallel
to ordinary
wall
Automaticclosure
single doors,
E 120
EI 120
Compliant
with APSAD
rule R16
Fireproof
compartment
REI 90 for
outer face
and EI 90 for
other faces
Not
applicable
Not applicable
Not applicable
A1 or
A2s1d0
Single doors
EI 90 &
A 120 (inner
face)
Single doors
E 90 (outer
face)
EI 120
Compliant
with APSAD
rule R16
APSAD Regulation
Metal-frame firebreak walls are not allowed unless they have a double face.
(See section 2.7.)
APSAD R15 rule: self-supporting firebreak walls were required for
reasons of symmetry, which appeared logical at the time, but not
now.
Traditionnal construction by concrete pillars
embedded in the floor
Fitted in front of
concrete pillar
Stringer
As an initial approximation, the firebreak capability of a wall in solid
prefabricated concrete panels can be calculated using the simple rules
set out in standard P 92-701 (DTU fire concrete), as shown in the
table below. These rules apply two walls with a slenderness ratio no
more than 50. The walls may be exposed to fire on one or both sides.
Frame
Firebreak
capability
½
hour
1
hour
1½
hours
2
hour
s
3
hours
4
hour
s
Loadbearing
walls
Thickness
(cm)
10
11
12
15
20
25
Nonloadbearing
walls
Thickness
(cm)
6
7
9
11
15
17.5
Concrete
frame
Concrete
framework
Fireproof joints
between
panels
Variant: panels
fitted between
reinforced
concrete pillars
BUT… deformation of free-standing
(i.e. self-supporting) wall embedded in floor
Initial position
Deformed position
Convex deformation on side
exposed to heat
Wall
Self-supporting firebreak walls:
potentially dangerous
The wall leans outward
from the fire if not free to
rotate at the foot.
This goes against the aims
of item 1510.
Former rules (APSAD R15)
• There is no straightforward, reliable method for designing a selfsupporting wall compliant with standards. Resort must be made
to sophisticated calculation models that are not in current
usage.
• Former rules do not allow for the effect of temperature gradient
when determining stress. (Text in extenso in R15 till 2007.)
• But the temperature gradient, and the second-order effects
thereof, is the main cause of wall collapse.
Conclusion
• Current recommendations (APSAD R15) should come under
serious critical review.
• Embedded pillars and outer façade shear walls should be
prohibited if they can be exposed to high temperature gradients.
• Interior firebreak walls embedded in the floor should only be
allowed if the effects of expansion and the resulting additional
stress on neighbouring structures can be properly evaluated.
Is full chaining really necessary?
Not if we can be sure that collapse will be in the right direction
without risk for the wall.
Classical deformation and possible solution?
Wall embedded at foot
and free at top
Wall supported horizontally at foot
and top
Wall curves gradually
In the scenario to the right, the wall curves less, so the weight offset is
less, and the risk of collapse is toward the fire rather than away from it.
As we said previously, thanks to its steel structure the Firebreak wall is
not concerned by this problem
Thank you for your attention
Contacts :
Fabrice Sokolowsky,
Innovation & Development Manager
fabrice.sokolowsky@arcelormittal.com
Frédéric Goujon,
Project Manager
frederic.goujon@arcelormittal.com