PART C
MECHANICAL AND ELECTRICAL SPECIFICATION
C1
MECHANICAL SPECIFICATION
C1.1 GENERAL
C1.1.1 Environmental Criteria
The following design standards are to be applied throughout the
University Estate unless stated otherwise in respect of individual
elements of a project. (Note: Separate environmental criteria apply
where designated animal facilities are being designed. The current
edition of the Code of Practice for the Care and Welfare of Animals
used in Scientific Procedures is the reference document for this
information).
Winter
Internal conditions:
CIBSE recommended design values for dry resultant temperatures
(CIBSE GuideA1).
External ambient:
CIBSE recommended method for external design dry-bulb
temperatures (CIBSE GuideA2)
Summer
Internal conditions:
Naturally ventilated - not to exceed +30C above external ambient
Mechanically ventilated and cooled – space temperature allowed to rise
0.5º C for every 1ºC that external temperature is above set point up to
a maximum of 26ºC.
i.e.
Set point 21°C
External Temperature 26°C
Difference 26°C - 21°C = 5K
Allowable rise 2.5K
Room control temperature 21 + 2.5 = 23.5°C
No upper and lower limits for humidity are set out above for general
environmental conditions. However, the summer internal standards
apply in winter to all mechanically ventilated and cooled areas for
humidity; the heating set point may be 19°C.
If the prescribed internal conditions cannot be, or seem unlikely to be,
achieved with natural ventilation or mechanical ventilation within parts
or all of the building under design, this is to be advised to the Project
Manager at feasibility or outline design stage.
C1.1.2 Noise Levels
The noise from remote or local plant installed to service any building or
facility within the building must not break out to cause annoyance to
either occupants or third parties or affect noise levels in adjacent
buildings.
Break-out from externally mounted plant or dedicated plant rooms must
not, under any operating conditions, exceed a background sound level
of 58 dBA (50NR) at 3 metres from the plant or plant room. The
exception to this is for standby generators, which may exceed these
criteria subject to location, housing and planning restrictions.
It should be noted that planning permissions may impose a limiting
noise criteria either at a site boundary, adjacent residential
accommodation or some other specified position. It will be the
designer’s responsibility to ensure planning conditions are complied
with.
Within buildings the internal noise criteria are generally as specified in
the CIBSE Guide A1; these are:
Interior of large lecture theatres
NR - 25
Interior of small lecture theatres
NR - 30
Office areas
NR - 35
Corridors and stairwells
NR - 40
Teaching areas
NR - 35
Seminar rooms
NR - 30
Laboratories
NR - 35
Concert halls and rehearsal rooms NR - 20
Toilets/washrooms
NR - 40
Designer must take full cognisance of vibrational transmissibility to
structure and specify suitable vibration isolation measures.
Designer must also make allowance for any directional quality to sound
production, e.g. axial fans
Note: For laboratories, the criteria apply without user laboratory
equipment in operation.
Note: For speech laboratories NR - 20 standards apply.
Note: All noise ratings in occupied parts of the building apply to air
handling plant (supply and extract grilles), heating systems, water
pumping and circulation systems and fume extract equipment forming
part of the fixed installation of the building.
Note: Portable, laboratory equipment is normally excluded from the
noise criteria requirements.
C1.1.3 Redundancy in Design (Design Reserve)
It is not normal University policy to over provide or over specify
mechanical services or install extensive items of standby plant
although to some extent this is provided for in the set points stated at
Clause C.1.1.1 (Environmental Criteria) and the requirement to size to
the outer limits of bandwidths or tolerances. The criteria to be applied
are as follows:
• Ambient design criteria (refer to C1.1.1); for animal
accommodation -10°C zero moisture content.
• Ambient summer design criteria (refer to C1.1.1).
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Design all plant to upper (plus) side of predicted bandwidth in
terms of humidity.
All boiler plant must be installed at 25% greater capacity than
calculated connected load.
Plate heat exchangers for LTHW to be dualled with each plate
rated at 67% of the maximum building load and shall be
braised for smaller loads and gaslected for large loads with the
most economical type being selected.
All chiller plant must be installed to the same capacity, +5% as
the calculated connected load (including animal
accommodation).
Main distribution pipework (all water services) is to be sized in
accordance with the sizing tables in the CIBSE design guide
(section B6 refers) plus 20%.
All main and branch ductwork distribution is to be sized so that
air velocities do not exceed 4m/s in supply ductwork, 5 m/s in
extract ductwork at maximum design flowrates. Final
connections to grilles to be sized to minimise re-generated
noise.
C1.1.4 Thermal Insulation/Trace Heating
The designer is to specify thermal insulation on all services as follows:
• All steam and condensate pipework
• All heating pipework
• All hot and cold water distribution pipework
• All cold water rising mains, make-up pipework and other
pipework carrying water that are in unheated areas, or where
there is the likelihood of local heating of the fluid or
condensation forming on the pipework.
• All chilled water pipework.
• All process pipework (excluding gasses).
• All refrigerant pipework.
• All hot water service cylinder and calorifiers.
• All chilled water storage vessels.
• All water storage tanks.
• All ductwork that has a heated/cooled/conditioned air stream
present and prior to entry to areas of delivery. (Extract
ductwork will not generally be insulated after any heat recovery
system or recirculation section nor air intake ductwork prior to
the first point of treatment/tempering).
In addition all insulated valves shall be readily accessible by being
enclosed, purpose made valve as AIC ISO covers or equal complete
with Velcro fastenings and drawstring closures.
Where thermal insulation is applied to pipes or ducts used to convey or
store fluids lower than the ambient dew point, a vapour barrier must be
applied to protect the insulation. The type of insulation is to be
specified by the designer; however closed cell elastomeric types are
now preferred (not fibreglass) secured with adhesive and joints
wrapped.
In all plant rooms, appropriate mechanical protection such as
hammered aluminium foil, or proprietary plastic sections (as
Isogenapak or equivalent) complete with end closers to terminations, is
required to all insulation. Ideally calorifiers, storage vessels and tanks
should be specified with a factory applied insulation. The use of PIB
insulation covering is not generally acceptable in plant rooms or boiler
houses.
Insulation thicknesses are to be the prescribed ‘economic thickness’ or
greater. Guidance on the calculation of the ‘economic thickness’ is
given in CIBSE publications and ‘Energy Efficiency’ guides published
by the Department of the Environment, Transport and the Regions
(DETR).
Trace heating shall be proprietary self-regulating type as Raychem or
equal and approved complete with all necessary junctions, terminations
etc, with all connections to be weather proof to IP55.
C1.1.5 Pipework and Pipework Identification
Copper pipework for heating or hot and cold water installations shall be
BSEN 1057 R250 (formerly Table X).
Where steel pipework to BS 1387 is to be used, the preference is for
heavy grade to be specified as standard throughout.
Where distributed steam and condensate pipework is used to supply
humidification points in ventilation systems (and any other similar
arrangements where chemical dosing or the addition of corrosion
inhibitors is inappropriate), both the steam and condensate return
pipework must be manufactured from an appropriate grade of stainless
steel. Copper, mild steel or galvanised steel pipework is not acceptable
for this application within University laboratories, teaching or research
establishments.
Proprietary pipework systems employing special tools to compress the
perimeter of the fittings to the pipe against a sealing ring will not be
considered for use within University buildings.
Where pipework installations are extensions to or partial replacements
of existing systems, the designer/specifier must ensure that the
specification of the new pipework (and identification) matches the
existing.
The requirement is that all pipework within plant rooms, boiler rooms,
roof voids, ceiling voids and service risers shall be identified.
Identification shall also be applied to services both sides of any wall or
floor penetration.
All pipework installed as part of a refurbishment or new build is to be
identified in accordance with BS 1710 and colours in accordance with
BS 4800. In addition to coloured identification bands it will also be
necessary to apply direction of flow arrows, abbreviated description of
service and flow/return identification.
A detailed legend in full colour shall be included as part of the contract.
The legend shall be suitably covered, framed and mounted in the
principal plant room.
C1.1.6 Commissioning and Setting to Work (Refer also to A5)
It will be the designer’s responsibility to ensure commissioning and
setting to work of all mechanical and associated electrical services are
properly carried out, appropriately witnessed and fully documented with
master copies of all documentation, test certificates and records
handed to the Project Manager on completion.
The designer has full responsibility for preparing a commissioning
programme and making sure this is written into the contract
documentation.
If ‘out of season’ completion of a project occurs, the designer has the
option of imposing a dummy load or delaying acceptance of handover
of some of the mechanical services until the appropriate prevailing
weather conditions. Any question in respect to the necessity of such
action must be resolved through discussion with the Project Manager
Once the mechanical services have been commissioned and set to
work, they must remain fully operational for a proving period with a
minimum duration of two weeks before acceptance by the designer. If
operating faults occur during the proving period this is to be extended
until two weeks operation free of defects is obtained. The designer
may not reduce the minimum proving period and the Project Manager
may call for a longer proving period as considered reasonably
necessary.
It is a requirement that due allowance is made for the instruction of
users and maintenance staff, nominated by the University, in the
correct operation of the mechanical services after commissioning. The
instruction may be required in separate sessions.
It is the designer’s responsibility to ensure all necessary monitoring and
test points, access arrangements etc are installed. He/she must be
present or represented at commissioning and static testing (see A5.3).
C1.1.7 Mechanical Drawings Retained on Site
For each plant room and services intake position it is a requirement
that the contractor shall prepare and fix in an agreed position a detailed
isometric drawing and valve chart, both suitably framed and covered.
The drawing shall indicate all plant and equipment, valves,
interconnecting pipework, plant numbers and valve numbers. The
valve chart shall indicate each valve number to correspond with those
indicated in the isometric diagram, a description of its function and
description of which system it applies to.
It is the designer’s responsibility to ensure the charts are properly
supplied, suitably fixed and accurate.
C1.1.8 Water Treatment
The designer shall be responsible for ascertaining the water quality to
be supplied to the system and shall specify any necessary water
treatment accordingly.
C1.2 HEATING
C1.2.1 Heating Systems
Old Aberdeen is served by a centralised LTHW distribution system with
individual buildings being connected via plate heat exchangers.
Generally, two plates per building are provided with each plate being
rated at 67% of full load.
Foresterhill Campus is served by a centralised steam distribution
system which is currently at or near capacity. Replacement of existing
plant with similar may be acceptable but new builds should include for
new high efficiency LTHW gas fired boilers
For all boiler installations in excess of 100kW, two or more boilers shall
be installed of equal capacity.
For all boiler installations, the total boiler capacity shall be at least 25%
greater than the calculated heat load.
In general the selected fuel is to be natural gas with 35 second oil as
alternative in Dual Fuel applications. Alternatives may be offered on
remote sites where it can be demonstrated that it would not be cost
effective to install a new gas supply, or where a detailed appraisal
including appropriate life cycle cost analyses indicate a more viable
alternative.
Calorifiers may only be used as a direct replacement or if this is to be
part of a domestic hot water system although this is not the preferred
design solution.
Flueing and ventilation arrangements are to be in strict accordance with
all current codes of practice and British Standards and the appropriate
certification must be supplied on completion of installation confirming
compliance.
The use of fan dilution systems, fan assisted flues or other similar
arrangements of the boiler flue is to be avoided.
So far as practicable, natural draught burners are preferred on boilers
and this is a requirement on all small (single installation) boilers. If
forced draught burners are used due account must be taken of the
noise these are likely to emit and any necessary noise attenuation,
including acoustic hoods, must be considered. (See C1.1.2 for limiting
noise criteria from plant).
The use of boilers requiring pumped primary circuits on multi boiler
installations is acceptable and the preferred option.
Where new boiler plant is installed to serve existing secondary system
strainers must be included within the design. These are to be of the
mesh type and be easily removable without draining down the primary
or secondary circuits. (This requires the inclusion of appropriate
isolation valves). Where existing systems are involved, the use of
proprietary dirt separators should be employed
C1.2.2 Heat Emitting Equipment
The objective in designing and installing heat emitting equipment is to
achieve a cost effective installation that is generally passive in
operation, requires little or no maintenance and has a long service life.
The following systems are not to be used unless, by written consent of
the Project Manager, it has been established that no other reasonable
alternative is practicable:
• Fan convectors that are concealed within false ceilings or
behind fixed panels or are otherwise difficult to access and
maintain.
• Fan convectors that have local automatic control valves
(control valves to each fan convector).
• Underfloor systems using steel or copper coils.
• Ceiling systems consisting of embedded pipework
• Embedded electrical systems (wall, ceiling or underfloor).
The type of heat emitting equipment proposed should be advised by
the consultant or design engineer to the Project Manager at an early
stage in design (outline proposals stage C).
C1.2.3 Gas Installations Serving Heating Plant
Negotiations with TRANSCO for the provision of a new (or alterations
to an existing) gas service on behalf of the University should be made
through the current gas service provider. Contact details may be
obtained from the University of Aberdeen Utilities Manager.
The consultant or design engineer must establish that any alterations
or additions to an existing gas infrastructure required as part of their
project, will not have an adverse effect on the service to existing
buildings or plant connected to that system under full load condition.
Refer to D8 for the gas installations requirements in respect to fire
precautions.
The gas distribution pipework installation downstream of the primary
gas meter is to be installed in accordance with the requirements of the
Institution of Gas Engineers and Managers (IGEM) and in particular
publication IGE/UP/2 Gas Installation Pipework, Boosters and
Compressors on Industrial and Commercial Premises.
Where new pipework is to be installed, IGE/UP/2 states:-
“4.4.3 For a supply that is normally metered at 21mbar, the pressure
drop between the primary meter and any booster or the plant manual
isolation valve, at maximum flow, should not exceed 1mbar”.
The Gas Safe Register have confirmed that they expect this to be
complied with. Therefore for all new (or alterations to existing) gas
distribution services installed on behalf of the University, it is now a
requirement that the pressure drop between the primary meter and any
booster or the plant manual isolation valve, at maximum flow, must not
exceed 1mbar.
Any alterations to pipework in excess of 25mm nb must be recorded on
revised drawings for display at meter locations.
C1.2.4 Heat Pumps/Split Systems and/or VRV
The use of heat pumps where appropriate may be considered. This
may be justifiable in circumstances where there is an academic need to
control temperature between specific limits and where the only practical
solution would involve cooling.
C1.3
WATER SERVICES
C1.3.1 Water Supply (Water Fittings) Regulations 1999
The lead consultant/team leader will be deemed responsible for
preparing and submitting the required notifications to the local water
supply undertaker as stipulated in the above regulations (unless
otherwise stated in the project briefing documentation). It is a
requirement of the regulations for such notifications to be in place prior
to commencement of work.
The requirements of this notification are briefly summarised below:
● To give notice to the water undertaker that he proposes to begin
work.
● The work shall not begin without the consent of that undertaker
which shall not be withheld unreasonably.
● The work shall comply with any conditions to which the
undertakers consent is subject.
For their part the water undertaker may withhold consent, or grant it
subject to conditions before the expiry of 10 working days from when
notification was given. If the water undertaker gives no notice within
this 10 working day period, then the consent required may be deemed
to have been granted unconditionally.
The wording of the regulations is such that the vast majority of projects
and a large proportion of minor works will require this prior notification
to the water undertaker.
Minor works or refurbishments particularly embedded within existing
buildings will have the potential for causing significant additional works
remote from the work area where, for example, modifications to the
building's main water storage tank are required. It is in the interests of
the Project Manager to arrange for such circumstances to be
investigated and costs included at inception or feasibility stage.
The water undertaker has a vested interest in protecting the incoming
water supplies to buildings against back contamination. University
buildings, particularly those including laboratories are understandably
viewed by the Water Regulations Officer as a particularly high risk.
The use of RPZ backflow prevention devices (stated in the regulations
as applicable to fluid category 5 applications), are to be used only when
the alternatives not subject to annual inspection requirements, have
been considered and found to be unsuitable for the particular
application. Details of all such devices must be submitted to the
Project Manager prior to tender stage.
C1.3.2 Cold Water Services
All new University building projects and those involving the extensive
refurbishment of existing buildings are now to include for the
segregation of the cold water storage and distribution systems serving
laboratories from those serving kitchens and those serving toilet areas.
Consideration of rainwater/grey water harvesting systems should be
given to any new build or major refurbishment project.
All domestic cold water services must include for tanked storage. It is
not now acceptable to the local water supply undertaker to provide cold
water services within the University Estate from a rising main unless
the water is to be used for potable drinking purposes or as a dedicated
supply to laboratory face or eye wash units. All such outlets are to be
appropriately labelled.
Water storage tanks, irrespective of size, must be constructed of GRP
or some other suitable form of plastic and shall be ‘by-law 30’
compliant. Internal flanges shall be avoided and tanks must be able to
be drained completely. Galvanised tanks or treated ferrous tanks are
unacceptable.
Without exception all drinking water must be supplied directly from a
rising main and the above ground pipework colour banded as
wholesome water (to BS 1710). Drinking water may not be fed from
any tanked storage within a building even if it is designed to be
dedicated for drinking purposes only.
All taps from which drinking water may be taken are to be clearly
labelled ‘Drinking Water’.
As far as practicable all non-drinking distribution is to be by gravity.
Pumped systems are to be avoided.
System design must include flow restrictors or automatically flushing
urinals, water saving devices or controls in toilets and, in conjunction
with the architect’s requirements, hot water flow restrictors on taps.
All cold water mains at entry to building must have a metric flow meter
installed reading in litres x10 or litres by 100. Water meters must be
able to provide a pulsed output suitable for connection to the University
remote metering system and shall be complete with relevant scaling
factors for each pulse.
The number of urinals, closets and hand wash basins must fully comply
with local building control standards or building design
recommendations, whichever is the higher, which are to be ascertained
by the Architect / lead consultant.
The complete design, installation and commissioning procedure (which
is to be defined in the contract documentation) must be in full
compliance with current codes of practice, Department of Health and
Social Security and Chartered Institution of Building Services
Engineers guidelines for domestic cold water systems. Where
requirements differ the higher standard shall prevail.
Particular care must be taken in the design, layout and installation of
cold water systems to avoid ‘dead legs’ and areas of low or stagnant
flow. This requirement is to prevent the formation of bacteria and to aid
system cleansing and sterilisation.
C1.3.3 Hot Water Services
The University policy is to close, as far as practicable, all central
heating circuits during the summer and provide only domestic hot water
from separate systems.
The system design, installation and commissioning procedure,
including sterilisation, shall be forwarded to the University Estates
Section a minimum of four weeks in advance of issue for tender to
allow time for assessment by the University’s Legionella consultant.
The system shall be designed, installed and commissioned fully in
accordance with the current codes of practice from CIBSE and HSE
ACOP L8. Where requirements differ, the higher standard should
prevail
Twin pump sets or standby and duty pumps with automatic changeover
are required for all water services with the exception of domestic hot
water services where a trapped pocket of warm water may present a
Legionella risk. A spare HWS pump is to be provided in these
circumstances fixed to brackets adjacent to duty pump with all open
ends suitably capped.
C1.3.4 Special Water
The University makes extensive use of ‘polished’, filtered and distilled
water systems (this may include dechlorinated and sea water). There
are varying requirements depending on the laboratory use, the user
department’s need and consumption and the novelty of experimental
work being undertaken. It is not therefore possible to offer any specific
advice or tabulate minimum standards; each installation will have to be
designed probably with detailed help from water treatment specialists,
and after detailed briefing from the users.
For the generation of distilled water the University has embarked on a
gradual programme of removing ‘stills’ and replacing these with more
modern and energy efficient reverse osmosis equipment. The use of
‘stills’ is now therefore not generally permitted for new installations.
It is a general requirement that all special water storage and distribution
systems be of plastic materials throughout; metallic components are
not to be used unless it is by positive recommendation of the water
treatment specialists engaged in the project under consideration. All
distribution systems shall incorporate any such specialists’
recommendations. Variations recommended by the installing
contractors must be viewed with extreme caution.
As far as possible manipulative/push fit joints are not to be used; a
welded/bonded arrangement for jointing of pipework is preferred.
It is recommended that very early advice from the users is to be sought
before system design is finalised.
C1.3.5 Laboratory Drainage
Laboratory and domestic drainage systems in scientific and technical
departments should be segregated to comply with the requirements of
the Water Industry Act, 1991. Laboratory drainage should be collected
to a minimum number of points (preferably one), where a sampling
manhole should be provided to permit samples of the effluent to be
obtained by the Regulatory Authorities for checking compliance with
trade effluent consent conditions.
C1.3.6 The Scottish Water Byelaws 2004
These Byelaws which came into force on 30th August 2004 under the
Water (Scotland) Act 1980 should be adhered to.
Refer to the Byelaws for full details.
As part of the Byelaws any person who proposes to install a water
fitting in connection with any operations listed in the table contained
within the act are required to give notice to the undertaker that:
1: they are to begin works
2: they shall not begin that work without the consent of the undertaker
3: they shall comply with any conditions to which the undertakers
consent is subject
Therefore, the designers should notify the relevant water authority
before work starts to ensure designs comply with the water byelaws
Also the contractors should be issuing certificates once the works have
been carried out to show compliance with the water byelaws.
It is also a University requirement that drawings MUST include
schematics of water systems (hot or cold) and must be passed for
approval to Connaught Compliance Services Ltd., who act as the
University’s advisors on Legionella Prevention.
Connaught Compliance Services Ltd.
Powke Lane Industrial Estate
Blackheath
Birmingham
B65 0AH
C1.4 VENTILATION
C1.4.1 General Ventilation Requirements
All areas of every building type must be properly and adequately
ventilated with fresh air. The minimum standards to be applied are
those set out in the CIBSE guide (B2) and the Building Regulations.
The minimum fresh air rate is not to be less than 8 litres per person per
second.
It is a requirement that, as far as practicable, ventilation is to be
achieved by natural means including opening windows, transfer grilles
and fixed louvres, with this arrangement applicable to offices, some
common or seminar rooms and general circulation areas.
Mechanical ventilation will more usually be provided to laboratory
areas, deep plan buildings, lecture theatres, larger seminar rooms and
where research or office equipment is located and requiring special
ventilation requirements. In these areas a ‘balanced’ system is
recommended.
Where ventilation equipment is also to provide some additional
temperature control in summer periods, which will require higher flow
rates or fresh air rates, then the use of a summer/winter fan setting is
to be provided in order to limit heat loss during winter periods or to
obviate the need for tempering the air during the winter period.
In all toilet areas, ventilation is to be by mechanical means and the
system is to be ‘extract’ only with make-up air drawn via transfer grilles
from the other parts of the building.
Similarly for smaller areas such as stores, plant areas, smaller offices
and machine rooms ‘extract’ only systems are preferred. The use of
modern heat recovery extract systems must be considered for all
simple ventilation systems.
For larger mechanical extract/supply systems which incorporate an air
handling unit the need for a heat recovery section is to be properly
assessed. The preferred method is to utilise a plate heat exchanger
arrangement but other alternatives such as thermal wheels and simple
run around coils may be appropriate for some applications.
All air handling units must be protected by fresh air motorised dampers
fitted at the intake position. The control and operation of these dampers
shall be such that outside air is prevented from entering the unit when
in the static or setback condition so preventing the risk of
backdraughts, windchill effects etc.
The preferred arrangement for all frost and heating coils fitted to air
handling units is for them to be supplied from a suitable constant
temperature heating circuit. Electric coils are to be avoided unless they
are found to be the only practical alternative. Direct gas fired
arrangements are acceptable on larger units in circumstances where
there is no available CT heating circuit and provided that the products
of combustion remain separate from the airstream. Refer also to
C1.2.3 in respect to the gas installation.
Air pressure regimes as recommended by various bodies (CIBSE and
HSE) may well be appropriate particularly where experimental work or
research is undertaken. For example, it may be necessary to specify a
‘balanced’ ventilation system for a laboratory giving a slight negative
pressure in the laboratory in relation to surrounding areas. The
overriding criteria is that the safety of people working within
laboratories or surrounding areas must be considered as the principal
element of the design. Therefore the ventilation plant should be
configured to draw contaminated air away from people and out of the
building rather than allow it to be distributed towards other occupied
areas.
There are various methods for ensuring contaminated extract air is
properly discharged from a facility including high discharge stacks, high
efflux velocities and high efficiency filtration. It may also, in certain
circumstances, be necessary to conduct wind tunnel tests or computer
modelling to ensure safe discharge. In all cases where the safe
discharge of contaminated extract air is being considered, the advice of
the University’s Safety Advisor must be sought.
For specific requirements for ventilation ductwork and control
arrangements in the event of a fire, refer to Part D7 of this document.
C1.4.2 Filtration (Air Systems)
All supply air handling, ventilation and make-up air equipment must be
provided with appropriate and properly specified filtration. The filters
are to be installed prior to any heater, chiller, fan or humidification plant
and must be selected to fully protect both the mechanical services
plant as well as the area being served. The only exception to this is
where finless frost coils are installed to protect the filters from freezing.
All filters shall be selected from standard available sizes. Where any
doubts arise, consult the Assistant Estates Director (Maintenance) for
details of the current filter suppliers to the University.
In all installations where high standards of cleanliness or filtration is
required, pre filters must be installed to prolong the service life and
performance of the main filter. This applies to all bag type main filters
(or better).
It may also be necessary to provide further close control filtration prior
to entry to the facility being served and downstream of the mechanical
plant. It is essential in such circumstances that safe and appropriate
access provision is made for routine filter changing (refer to Section B1
for accessibility requirements).
All panel and bag filters must be securely fixed yet easily withdrawable
(folding or bending to remove or install is not acceptable). Slide out
side withdrawal frames are to be used as standard in all air handling
unit applications. Combination frames are available to suit both filter
types. Where access requirements dictate, bottom withdrawal frames
may also be considered as a last resort when all other practical
alternatives have been eliminated. However, due regard must be given
to Health and Safety requirements in respect to routine filter changing
throughout the service life of the plant.
The use of expensive filters such as roll systems, activated charcoal or
similar are not to be specified except where required after full appraisal
of available options. If serious risk of contaminated air being drawn
into a system is likely then the air intake ducts must be relocated.
High Efficiency (HEPA) filters must only be specified where there is a
specific requirement for high levels of filtration (e.g. certain research
laboratories/animal facilities etc.).
All filters/filter sections are to be installed with a means of indicating the
filter clean/dirty status and highlighting the point at which the filters
need changing. The preferred method is the use of differential pressure
switches linked to the Building Management System. (This
requirement does not apply to roughing or pre-filters). As a backup,
and for smaller or more remote applications where there is no BMS,
the use of manometers (or similar) with the correct operating range
clearly marked on the indication system are required.
Extract systems generally shall not contain filtration except where heat
re-claim in the form of run-around coils or cross-flow heat exchangers
is incorporated.
Where the discharge is considered to be a risk to nearby people or the
environment then additional filtration specific to the risk shall be
installed e.g. pathogens, high levels of particulates, antigens etc.
Where such considerations arise, the advice of the University Safety
Advisor is to be sought at the earliest opportunity (preferably outline
design stage).
Written confirmation of any recommendations, requirements and
actions taken must be provided by the designer to the relevant Project
Manager.
C1.4.3 Humidification (Including Dehumidification)
Humidification (or dehumidification) is rarely a specific requirement
within University accommodation and modern computer systems
require close control of humidity less frequently. Therefore when the
consultant or design engineer is requested to provide “air conditioning”
it should be clarified at a very early stage (feasibility) if “air
conditioning” includes humidity control or is limited to only temperature
control (both heating and cooling). This clarification is fundamental to
the design and will have major and unnecessary cost implications if
humidity control is provided when in reality it is not necessary.
As a general rule, humidity control will only be required within the
following facilities within the Estate:
• Medical research facilities subject to the applicable Home Office
code of practice.
• Specific areas within museums and special libraries and
archives.
• Chapel to protect the organ and fretwork.
• Where specific academic requirements dictate.
Any other requests for humidification or de-humidification must be
agreed by the Assistant Estates Director (Maintenance) prior to being
included in the design for new or refurbished works.
The preferred method of providing dehumidification is using a cooling
battery to depress the air flow below the local dew point.
The use of heating systems, dehumidification wheels and similar
arrangements is not acceptable.
Local absorption bags (using hydroscopic media) may be acceptable in
limited circumstances such as display cabinets or storage boxes. It will
be the users’ responsibility to monitor and maintain said items.
Acceptable methods of providing humidification are as follows:
● Steam injection from separate or remote steam raising plant.
● Steam generators using resistive element type electrode
technology
● Direct gas fired humidifiers.
All units must be sized at maximum rating requirements, i.e. to operate
in dry air at set point plus tolerance (55 ± 5% RH means delivering at
60% RH) at maximum air flow rates.
The use of water systems such as sprays, spinning disc, immersed
wheels or any other system which uses water at a temperature below
70°C is not generally acceptable. In the event of a consultant or design
engineer electing to propose such a system, they must include within
the proposals full details of all necessary systems to eliminate the risk
of legionella, bacterial and fungal growth or any other associated health
risks. Initial proposals are to be specifically presented to the Project
Manager for review at scheme design stage (D). Written acceptance
(conditional or otherwise) must be received by the consultant or design
engineer prior to them progressing this aspect of the design to the next
stage.
C1.4.4 Extract Ventilation Plant Including Fume Cupboards
The University makes extensive use of fume cupboard facilities,
microbiological safety cabinets, containment cabinets, fume/dust
extract hoods etc. All these systems will have different operating
requirements, types of materials (vapours, gases, organisms,
particulates etc) to safely discharge and therefore will be subject to
separate design criteria in terms of:
• Supply air requirements and filtration.
• Siting of supply grilles
• Extract air flow rates, filtration and discharge.
• Face velocities or system velocities or flow rates.
• The level of cabinet containment required by the application or
usage.
• Pressure regimes cabinet to room, room to room, or room to
corridor.
• Extract air terminations, location, discharge and filtration
requirements.
• Materials used in construction of extract ductwork, extract
cabinet and fans.
• Support services including fire suppression as part of the
containment system.
All these items must be considered by the consultant or design
engineer at feasibility stage (B) and in conjunction with the user
requirements, the advice from the University Safety Advisor, and if
necessary the School of the Biological Sciences must be sought.
In respect of fume cupboards, the requirements of BS EN 14175 –
1:2003, BS EN 14175 – 2:2003 and the remainder of BS 7258 must be
applied. Any requests for deviation must be addressed to the
University Safety Advisor and must not be adopted without his/her
specific agreement. The following specific requirements apply to fume
cupboard installations within University laboratories:
•
•
•
Extract ductwork to be suitable for and compatible with the
media that it is intended to contain.
Where fume extract ductwork passes through fire
compartmentation, measure must be taken to either: a) ensure
ductwork is enclosed in its own fire compartment either by
encasing ducts in suitably rated materials, b) manufacturing
ducts from suitably rated materials which also do not react with
the chemicals within fumes being discharged, c) suitable
treatment of the ductwork.
The use of fire dampers should be avoided if possible but if
there is no alternative, the dampers selected should be of
suitable corrosion and fume resistant design with damper blades
clear of the airstream. The fusible link must also be suitable for
the fumes being discharged to prevent premature failure. If
installed, fire dampers must be accessible for maintenance/
replacement.
Leak-proof inspection covers should be provided as necessary to
permit inspection and cleaning of the entire internal surface of the
system.
Duct work must be suitably labelled at these points to indicate the
nature of the hazard.
• Multiple installations or dilution systems should be avoided.
Proposals for use of such systems should be forwarded to the
Assistant Estates Director (Building Services)/ University Safety
Advisor for approval. Any such proposal must detail facilities for
minimising energy consumption.
• Control systems which maintain a constant face velocity must be
considered for all fume cupboard extract system which have a
maximum flow rate in excess of 0.25m3/s of air.
• The design face velocity at a rash height of 0.5m shall be a
minimum of 0.5m/s but this will be subject to user requirements.
Lower face velocity fume cupboards may be considered but full
evaluation and acceptance by the users will be required prior to
specifications.
•
All systems must have suitable containment testing carried out
“in situ” even if the commissioning data meets or exceeds the
above criteria. The University Safety Advisor must be given the
option of sending a representative to witness any such testing.
• The use of recirculating type fume cupboards which rely solely
on the performance of the filtration system for safe operation is
generally not acceptable unless specifically agreed in writing by
the University Safety Advisor or his/her delegated
representative. The subsequent usage must clearly be restricted
to fall safely within the capabilities of the filter media.
• The fume cupboard extract fans and discharge stacks must be
fitted with permanent labels clearly identifying the reference
number and location of the fume cupboard(s) to which they are
connected.
• In cases where the fume cupboard fans have to be located
inside plant rooms i.e. where there is a ductwork connection to
the discharge stack under positive pressure within the building,
the plant room will become a designated “permit to work” area.
On new buildings, this arrangement should be avoided wherever
possible. On existing buildings or where there is no practical
alternative, the design of the plant room must include adequate
ventilation to eliminate the possibility of the build up of
potentially harmful fumes.
• If the extract system performance is in doubt or the risk of
discharge affecting nearby people or buildings is regarded as a
possibility, then it may be necessary to conduct wind tunnel
tests irrespective of whether the relevant sections of the British
Standards are complied with. The advice of the University
Safety Advisor or his/her delegated representative must be
sought at feasibility stage (B).
Refer to D7 for the fire precautions requirements in respect to extract
ventilation plant including fume cupboards.
C1.5 COOLING
C1.5.1 Cooling Systems
In general full air conditioning or local cooling is not the standard
throughout the University Estate where it is solely installed for the
general comfort and well being of individuals or group of individuals
during the ‘summer’ period. This standard is to be applied to all new
buildings or refurbishments undertaken by external consultants.
Air conditioning or local cooling may only be installed if:
• It is required by regulation or enforceable code of practice (e.g.
Home Office Scientific Procedures), or,
• There is a specific identifiable academic need (such as chemical
deterioration at elevated temperatures), or,
• Excessively high internal space temperatures are likely to be
experienced and there is no other practicable means of reducing
heat gains. (In this context “practicable” will include natural
ventilation, local ventilation, thermal store or passive solar
measures such as shading, orientation and high structural mass).
If, after a proper evaluation, air conditioning or cooling is an essential
requirement, then before detailed design commences the exact
parameters must be agreed with the users as well as the Assistant
Estates Director (Maintenance). The use of heat pumps may also be
considered at this stage (refer to C1.2.4). It will not be acceptable to
install a fully ducted air conditioning system, with humidity control, if
local temperature control will achieve the desired objective. In this
respect the consultant or design engineer will have to fully justify the
proposed methodology.
If the case to be made for a fully ducted air conditioning or cooling
system is not clear and that a mechanical ventilation system may
achieve sufficiently close control of ‘summer time’ internal
temperatures, it is recommended that the ductwork system or air
handling unit be so designed that the retrofit of a chiller battery is
readily achievable. The preferred method of introducing a chiller
battery is by including an easily removable blank section in the
ductwork or air handling unit. Similarly, provision of any associated
controls requirements should be allowed for in the cable
containment/outstations.
The design, selection of equipment and controls strategy is a matter for
the consultant or design engineer to decide, but in general the following
are required by the University in meeting the desired objectives:
• External ambient temperatures (dry-bulb and wet-bulb) to be
derived from CIBSE Guide (A2) for the purpose of sizing
equipment. (Chiller batteries, dehumidification equipment and
fans).
• Direct expansion cassette units (wall or ceiling) are the preferred
solution where local cooling only is required. The use of variable
refrigerant volume (VRV) systems may be used where a number of
internal units are installed in relatively close proximity.
• In such applications the controls of both heating and cooling
systems serving the same area must be interfaced via the BMS
and set to eliminate the chance of both systems operating in
conflict with one another.
• The use of internal duct mounted condensers is not acceptable.
• Small chilled water systems are only to be used where closer
control is a particular requirement, or on larger installations
(possibly via a ductwork distribution network) where the total
cooling load is typically in excess of 60kW.
• The use of open circuit water cooling towers is prohibited.
• All direct expansion systems must use a refrigerant gas of low
ozone depletion characteristics (the use of R11, R12 and R22
refrigerant gases is not acceptable). In this respect the terms of
the ‘Montreal Protocol’ as amended by European Directive is to
apply.
• Where existing DX systems are to be re-used, the above
requirements still apply in respect to the acceptable types of
refrigerant gasses.
• Packaged unit, catalogue models or other standard arrangements
are to be specified. The use of specials, one-off designs or
otherwise bespoke designs for chiller units are to be avoided.
• Chillers should be specified, where economically viable, to
incorporate free cooling circuit(s). (see section C1.5.2)
• Where chilled beams are considered, the design must include
appropriate measures to gain access to the full extent of each unit
for cleaning and maintenance. The preferred arrangement is for the
beams to be of the exposed type.
• All grouped/central controls associated with DX equipment
(including VRV systems) must be interfaced with the applicable
Building Management System. Access available to users for
adjustment shall be limited to temperature only unless otherwise
advised in the briefing document.
• Every effort should be made to ensure condensate from heat
exchange coils flows to drain by gravity. Lift pumps from ceiling
cassettes should discharge to an adjacent gravity drain.
• Where systems are installed primarily for occupier comfort, control
of the operation by presence detection or similar control should be
included.
• To achieve the benefits of energy saving, low maintenance and
occupier comfort, inverter controlled compressor systems should
be specified.
• While not attempting to limit the application of any manufacturers’
equipment, for commonality of equipment preference should be
given to the following makes:
Daikin, Mitsubishi, Airedale, Carrier, Toshiba, Marstair and IMI.
Alternative technologies refrigerants may be considered e.g., reverse
cycle heat-pumps, ammonia etc, but full assessment of environmental
impact including noise, running costs, life cycle costs, global warming,
potential, ozone depletion potential, flammability, toxicity etc must be
carried out.
C1.5.2 Chillers
Note that mechanical cooling should be considered only if passive
systems are not viable. Where central chilling plant is installed, the
plant should be as follows:
Loads up to 400kW should be multi-circuit scroll compressor type fitted
with free cooling section to improve efficiency and reduce carbon
dioxide emissions. Alternatively, based on cost benefit analysis,
Turbocor compressor type.
Loads over 500kW should be selected based on load profile conditions.
Where load conditions are continually above 70% full load then screw
compressor should be the first option.
Where load conditions fluctuate and part load conditions of 50% or less
predominate then consideration should be given to Turbocor
compressors.
For their higher cooling loads, consideration should also be given to
installing an air blast cooler (dry air cooler) to free cool the water prior
to entering the chiller.
All chiller plant should be Eurovent performance guaranteed, preferably
A rated.
C1.5.3 Refrigerants
The use of refrigerant gases in mechanical services plant is covered by
the Montreal Protocol and subsequent amendments issued by the
European Commission or Government following the Kyoto agreement.
The University therefore require all consultants and design engineers
working on its behalf to comply.
As part of the design process, the responsible design engineer (or
consultant) must consider appropriate means of condensate removal
including any routine or reactive access requirements.
In effect, this means that refrigerant gases with a low or zero ozone
depletion potential (ODP) must now be specified in all mechanical
services plant and that gases coded R11, R12 and R22 may not be
used under any circumstances
The currently acceptable (ODP) refrigerants are as follows:
R407C
R410A
R134A
R404A (Coldroom applications)
It is accepted that the above list will be subject to change and the
actual refrigerant selected will depend on the application. Therefore,
the type of refrigerant gas intended to be used within a proposed
system must be declared at outline proposals stage (C).
Where a consultant or design engineer is involved with a scheme that
requires removal of an existing system containing a refrigerant gas, the
project specification must include for refrigerant recovery and safe
disposal irrespective of the ODP of the charge.
Deliberate discharge of any refrigerant gases to atmosphere will be
regarded very seriously by the University.
C1.5.4 Cooling Towers
Under no circumstances are open circuit cooling towers to be specified
as part of a heat rejection system. If an existing cooling system, which
incorporates a cooling tower, is to be fitted, refurbished, extended or
otherwise adapted, the open circuit element is to be permanently
removed from service concurrently with the works and replaced by a
closed or direct gaseous heat exchange system.
C1.6 BUILDING MANAGEMENT SYSTEMS AND CONTROLS
C1.6.1 “Stand Alone” Systems & General Controls Requirements
In certain circumstances, where the building services plant is very
small, remote or only serving ‘domestic’ type accommodation, “stand
alone” control systems may be installed. In such circumstances, the
design engineer or consultant must be able to demonstrate that it is not
cost effective or that there is no practicable benefit to be obtained from
having the capability for remote monitoring. These systems shall only
be installed with the express authority of the Project Manager.
Where the requirement for 24 hour monitoring of critical alarms exists,
the cost of linking these signals to the Security Control Room via the
‘Bold’ system must be identified and the work included within the
project at feasibility or at outline proposals stage (C).
All control systems are to have the following minimum functions/
features:
• Optimum start
• Optimum stop (over 100kW connected load only)
• Multiple ‘On’ and multiple ‘Off’ functions per day
• Seven day programme with ‘day omit’ function
• Separate programme of Heating and DHW
• Ancillary switching controls for local ventilation/water heating
equipment
• 'No volt’ contacts to give common fault alarm to Security Control
Room
• Control Panel Lamp indication: SUPPLY ON, RUN, FAULT for
each connected device.
• A common lamp test facility
• Where applicable, a BMS Operating Interface allowing local access
to relevant data.
• Air Handling Unit - on/air flow failed/fault
• Air Handling Unit - filter status - dirty
• Duty/standby pumps – No1 run/fail, No2 run/fail, flow failed.
This applies to all systems that are used to provide environmental
control.
C1.6.2 Building Management Systems
All control systems for heating, cooling and ventilation equipment must
be compatible within the existing systems and ‘Front End’ facilities
currently in service on the University Estate.
For all new buildings and major refurbishment projects, only the
following building management systems will be acceptable:
• Trend:
DDC system
Provided with a 963 Supervisor front-end
facility
For building extensions and minor refurbishments where there is no
BMS already in use within the building in question, systems indicated
above shall be used
In the event of there being a BMS already in use this should be
extended to incorporate any new plant.
The above Trend, systems are marketed through a network of
manufacturers approved systems houses and so providing the
opportunity for obtaining value for money through competitive
tendering. Contractors should be selected from the University
approved list.
All BMS control systems are to include the same minimum functions
stated in C1.6.1 above.
It is important that the consultant / design engineer makes full
allowance in both the design and cost estimates for all necessary
interfaces, cable connections (including fibre optics), software
configuration, graphics, testing and commissioning to allow full
operational use of the Front End facility functions. These systems must
be commissioned and fully operational at practical completion.
Two copies of the BMS programming software must be provided at
practical completion on CD Rom or similar approved storage media.
The Project Officer will be responsible for ensuring that this software is
provided and handed to the Assistant Estates Director (Maintenance)
at practical completion.
C1.7 LIFT AND ALARM LINES
The university will provide an analogue line from the designated wiring
hub patched to a UTP structured wiring point installed adjacent to the
lift control or fire panel. Where the UTP outlet has not been fitted or the
engineer chooses to make a screw terminal connection, the line will be
presented on the Blue-Blue/White pair.
This line will normally be an analogue PBX extension from our Mitel
systems which presents internal dial tone at 26v.
Analogue lines on the Foresterhill Campus may be provided from the
NHS Mitel system which presents internal dial tone at 26v.
In some cases for lifts, we may provide internal dial tone from an IP
adaptor.
Occasionally, where no internal telephony network exists, we may
provide a standard 50v BT line.
All extensions provided will have a four digit extension number and will
be DDI, i.e. Can be called from outside with a prefix. These numbers
(or the BT number) will be provided at the time of installation.
Extensions will have national access and be barred from dialling mobile
numbers unless there is a specific need.
C1.7.1 Lifts
Lift diallers converted to a University extension need to be programmed
to dial 4910. If test calls or calls to a control centre need to be made,
the number dialled must be prefixed with a 9. Calls to 01*********
without a 9 prefix will result in the call ringing the University
switchboard.
Lift diallers connected to a BT line need to be programmed to dial
(01224) 274910.
Lift Diallers on the Foresterhill Campus connected to an NHS extension
need to be programmed to dial 764910.
C1.7.2 Alarms
Alarm diallers converted to a University extension need to be
programmed to dial 3390. If test calls or calls to a control centre need
to be made, the number dialled must be prefixed with a 9. Calls to
01********* without a 9 prefix will result in the call ringing the University
switchboard.
Alarm diallers connected to a BT line need to be programmed to dial
(01224) 273390.
Alarm Diallers on the Foresterhill Campus connected to an NHS
extension need to be programmed to dial 763390.