Smoke Control and Day To Day Ventilation For Multi-Storey Residential Buildings
Smoke Control and Day To Day Ventilation For Multi-Storey Residential Buildings
Smoke Control and Day To Day Ventilation For Multi-Storey Residential Buildings
• Smoke entering the stairs can make escape difficult for In addition, we look at opportunities for a smoke control system
occupants of higher storeys and slow down fire-fighters on to provide both smoke control and day to day ventilation.
their way in.
• In taller buildings the fire and rescue services need clear access
to stairs and lobbies to form a bridgehead for operations, using
a fire fighting shaft which is protected from smoke.
3
The legislative framework and standards within the UK
The legislative requirements derive from Smoke control systems are required to The requirements are set out in ADB, BS
the Building Regulations for England and protect the means of escape (MOE) for 5588-5, BS 9991 and BS 9999.
Wales (2010). Detailed recommendations the occupants.
to meet these requirements are provided See our “Ventilation for fire-fighting stairs”
in Approved Document B (ADB). Please Furthermore there is a requirement for leaflet for further information on those
note that the Building Regulations for buildings with a floor more than 18m buildings which fit within this category.
Scotland and Northern Ireland vary in above fire service access level or with a However in residential buildings ADB
some details. basement more than 10m below it to have does not require a fire fighting lobby or
a protected fire-fighting core with a fire the higher performance ventilation system
For apartment buildings, the most up to fighting lift whether these be residential that such a lobby would require.
date guidance is contained within ADB. buildings or not. Certain other buildings
just require a fire-fighting core.
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Smoke control for means of escape (MOE) in residential buildings
7500mm
Max
Approved Document B (ADB) accepts For small single stair buildings: If the For all other kinds of residential
that, in the event of a fire in an apartment, building is under 11m high, has no more buildings: In all other apartment buildings,
7500mm
some smoke will spread from the than 3 storeys and the staircase does not the travel distances are limited to 7.5m
Max
7500mm
apartment into the corridor as the connect to a covered car park, then only in one direction and 30m if escape is in
Max
occupants make their escape. a stairwell ventilator is required, provided two directions, and any corridor or lobby
7500mm
that the escape distances are limited to that opens onto a staircase should be
7500mm
Max
Max
Consequently, it is a requirement that 4.5m in the corridor. If the corridor is also ventilated. If BS 9991 is being followed,
any corridor or lobby that opens into ventilated, then escape distances can be a dead end travel distance of up to 15m
a staircase has ventilation to allow extended up to 7.5m. See below and pages is permitted in buildings with sprinkler
7500mm
that smoke to be removed and, most 6-7 for the Colt Shaft System. protection to all apartments.
Max
7500mm
7500mm
Max
getting into the staircase.
7500mm
Max
Stairwell ventilator
7500mm
Max
7500mm
Max
7500mm
Max
7500mm
Max
7500mm
Max
7500mm
Max
7500mm
If the corridor has outside walls, as in • Extends at least 0.5m above the highest Operation of the ventilation system
figure A, then an AOV is a suitable means structure within 2m If the apartments have access only to one
of ventilation, with a minimum free area • Extends 2.5m above the ceiling of the escape stair, the system must be linked to
of 1.5m2. highest level served by the shaft an automatic detection system.
• Is constructed from non-combustible
If the corridor is landlocked, as shown in material and the vents are equivalent to On detection of smoke in the corridor,
figures B or C, then a shaft system will an E30S fire door the vent on the fire floor, at the top of
be required. This can be either natural or • Is vertical with no more than 4m at an the shaft and the top of the stair should
mechanical. inclined angle (max 30°). all open simultaneously, and vents on all
7500mm
Max
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The ADB shaft
In 2006 the ADB smoke shaft was introduced. The requirement
is for a 1.5m2 cross section shaft with a ventilator at the top
and 1m2 dampers to each lobby, and there is no requirement for
inlet air at ground level. Automatic ventilation is required to the
stairs, comprising a 1m2 AOV at the head of the stairs. BS 9991
now mentions the ADB smoke shaft as an alternative form of
ventilation to an AOV scheme or pressurisation.
This shaft performs as well as or better than the ADB shaft and
requires only 40% of the shaft area.
Fire Floor
More effective ventilation combined with Lobby
space-saving Stairs
The Colt Mechanical Shaft, which is suitable for use in any stair
core (escape or fire-fighting), requires a shaft which can be as Figure D
small as only 0.6m2. This represents up to a 60% reduction in
the floor space required. It opens up the space on each floor,
which allows architects to be more creative in their designs, and
improves the saleable or lettable space for the client. This in turn
increases the profits for developers and the income for landlords,
and permits more usable space.
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The Colt Mechanical Shaft in detail
The Colt Mechanical Shaft solves a common
problem associated with mechanical extraction.
Since the lobby is fire rated, it is usually well
sealed, so even a small amount of extract will
cause a high negative pressure in the lobby, which
could make doors difficult to open and could
cause smoke to be drawn into the lobby from
the fire compartment, with devastating effect.
With all doors open, the fan runs at full speed to extract smoke
discharging from the accommodation. With all doors closed, the
fan runs at minimum speed to help mop up any smoke leaking
past the closed door. In intermediate conditions, the fan speed
modulates to ensure adequate ventilation without excessive
depressurisation.
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The Colt Shaft Extended Corridor system
A further development of the Colt Mechanical Shaft is the
Colt Shaft Extended Corridor system, which can extend travel
distances in means-of-escape corridors.
Source of Extract
inlet air point
Source of X up to approx 25m X Extract
inlet air Point
Figure E Colt Extended Corridor Solution removes the need for one
staircase and cross-corridor fire doors
The Extended Corridor system out-performs the conventional
solution for both evacuation and fire-fighting. Justification and approval for extended
The system is generally unaffected by external wind pressures, so
travel distances
is inherently more reliable than a natural system. Since extended travel distances are an area of design risk,
we would always recommend talking to Building Control
The system achieves exceptional smoke extraction performance early to obtain agreement in principle.
by utilising a corridor extraction system at one end of the
corridor and a dedicated air inlet system at the other. At the detail design stage, CFD analysis is inevitably required
to satisfy the authorities that the proposed system provides
There are four types of Extended Corridor system: adequate performance. Originally CFD was simply used to
(a) Pull system – mechanical extract / natural inlet show that conditions were demonstrably better than for
(b) Push system - mechanical inlet / natural exhaust a compliant solution, but nowadays it is more common to
(c) Push-pull – balanced system. show compliance with set performance objectives. The SCA
(d) Push-pull reversible - balanced system but with added publication, “Guidance on smoke control to common escape
flexibility. routes in apartment blocks” provides guidance on what
these objectives might be.
It is available as a free download from www.feta.co.uk.
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With extended travel distance systems, location is critical!
In a compliant building the location of the smoke outlet from the lobby or corridor is
Help resources
not legislated for. As long as the system is compliant it can be located anywhere. For an
For further help resources on
extended travel distance system it’s very different. Location is critical.
designing smoke shaft systems, please
visit our blog:
On these systems:
http://blog.coltinfo.co.uk/topic/
• The inlet and extract should be as close to the opposite ends of the corridor as
smoke-shaft-series
possible
• The direction of air flow should draw smoke away from the stairs whenever practicable
This series covers a variety of topics
• Mechanical extract is usually preferred
including builder’s work shafts, noise,
• Remember that if natural inlet is used, it needs to be generously sized to avoid
power, extended travel distances,
excessive depressurisation of the corridor.
natural vs mechanical shafts, smoke
ventilation only and dual purpose
The aim is to continuously flush through the corridor to ensure that any smoke entering
systems.
from the fire room is quickly extracted, keeping the corridor fully tenable except when
the fire room door is open and for a short period after it is closed.
LABC Certification
The Colt Shaft Variable and Colt Shaft Extended Corridor systems are LABC Registered
Systems because of their superior performance as proven by CFD.
Improved effectiveness
Colt has carried out extensive CFD modelling in both escape and fire-fighting modes, and compared its Extended Corridor Solutions
with a compliant corridor that has a natural AOV system. In the model zero wind conditions have been assumed in assessing the
relative performance of the AOV. A typical example is shown below.
This modelling shows that in the early clear conditions for evacuation although a smoke spill out, completely filling the
stages of the fire, the two systems ceiling smoke layer hangs around with the corridor, and the AOV system is
perform satisfactorily. The fire starts in an AOV. At this stage, the fire is relatively overwhelmed. However, once the
apartment, the occupants evacuate and small. Ten minutes later, when the fire apartment door is closed, the mechanical
smoke spills into the corridor. Both the brigade open the apartment door, the fire system can clear the corridor within 60
AOV and the mechanical system keep is much more severe. Large volumes of seconds.
Figure F Figure G
Figure I
Conventional approach
After the same amount of time in the corridor equipped with
a conventional AOV, the visibility in almost zero - the corridor
is still completely smoke logged.
Pressurisation systems protect Pressurisation systems offer these Protecting escape routes: Smoke shafts
benefits: versus pressurisation
escape routes against the • Protection of escape routes
ingress of smoke by maintaining • Compliance with Approved Document B How do you decide which to use? The
and BS EN 12101-6. decision is influenced by legislation
the pressure higher than that However pressurisation systems are and standards, building configuration,
in the adjacent spaces. generally relatively expensive, so they are budget and space requirements. There is
normally only used where demanded by no universal “right” choice, but there’s
regulations or standards or by Building certainly a best choice for each individual
Control, usually as a trade-off. building. We can advise on this.
Help resources
For further help resources on
making the choice between designing
a smoke shaft or a pressurisation
system, please watch our recorded
webinar from: http://blog.coltinfo.
co.uk/smoke-shafts-v-pressurisation.
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How a pressurisation system works In residential buildings it is usually impractical to carry
pressurisation up to each apartment door due to the
A pressurisation system provides supply air (where air is difficulty of providing air release from each apartment.
injected into the area that is to be protected), pressure Therefore stairs and lobbies are usually pressurised with
relief (to avoid overpressure when doors are closed) and air release from the corridor.
air release (air and smoke is released from the adjoining
fire area). Combining these elements creates a positive Pressurisation systems need to meet the
pressure difference which prevents lobbies and staircases recommendations of Approved Document B and BS EN
from filling up with smoke. 12101-6 “Specification for Pressure Differential Systems”
or BS 5588-4 - “Code of practice for smoke control using
pressure differentials”.
System components
Stairs Accommodation
A pressurisation system comprises:
• Inlet fans for introducing air into the
designated area. The run and standby
fans and control equipment should be
housed in a separate plant room or
outdoors and the inlet should be
protected from smoke. Dual inlets with
automatic smoke dampers are required
for roof level inlet.
• Ductwork and outlet grilles, to provide
distribution of air exactly where it is
needed.
• Pressure relief dampers, to release
excess air in the closed door condition
from the stair area. This should be
ducted to discharge directly to Stairs Accommodation
atmosphere independent of the wind
direction. Damper blades are set to start
opening at 50 Pa pressure differential. Vertical
shaft
• Automatic air release to prevent Powered extract
unwanted pressure build up in the
adjacent spaces. This may be automatic
vents, natural shafts or mechanical
extract systems.
The control system should operate
automatically from the smoke detection Natural air release
system with a manual on/off switch also
provided within either the pressurisation
plant room, near the building entrance (to
suit the fire service), or within the central
building services control room.
System requirements back the smoke on the fire floor when the door onto the fire
floor is open.
Two requirements need to be maintained within a pressurisation
system. These are: Getting the right balance for a pressurisation system needs careful
design in order for the system to work effectively. Insufficient
• Maintaining a pressure difference for a closed door condition. pressure difference across a closed door will allow the passage
Here the pressure difference is required to overcome buoyancy of smoke into the protected space. Excess pressure will impede
pressure generated by the hot smoke layer, expansion of the door opening and hence escape.
gases in the compartment due to heating, stack pressure and
wind pressure. It is critical that the walls to pressurised areas should be
carefully constructed to minimise air leakage and that all services
• Maintaining a velocity for an open door condition. Here penetrations should be properly fire stopped.
maintaining a velocity for an opened door is required to hold
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Product options: roof/façade ventilators
Casement versus louvred AOVs
Approved Document B requires that lobbies / corridors should
be ventilated by an AOV with a free area of at least 1.5m2. This
does not sound like very much, but the definition of ‘minimum
free area’ for an AOV makes this difficult to achieve simply with
opening windows.
12
Product options: roof / facade ventilators
These natural ventilators can be used at the head of a shaft, in the stairwell or as AOVs.
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Product options: shaft ventilators
All these components have been designed with Colt Shaft systems in mind. They can be controlled as part of the shaft system network,
and also be addressed and linked via an OPV system to the fire alarm system.
All systems are minimum E30S rated, that means 30 minutes fire integrity and smoke sealed.
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Olympic Athletes Village, London
Enabling a smoke control system to Please go to the Colt blog to access the “Ventilation solutions
for overheated corridors in residential buildings” whitepaper,
provide both smoke control and day to day which describes the options and pros and cons of each of the
ventilation following approaches in detail:
The quest for energy efficiency has led to very good sealing • Natural ventilation using AOVs. See pages 12-13 for the product
and insulation in residential buildings and an increase in district options.
heating schemes. This has unintended consequences for stair
lobbies, corridors and entrance halls, which tend to overheat, • Natural ventilation or mechanical ventilation using shafts. We
resulting in unpleasant conditions for residents and possible issues have described the various options for shafts in detail above,
maintaining cold water supply temperatures. see pages 7-9 and 14. This can involve either smoke fans with
separate day to day fans, or inverter-controlled dual purpose
One solution may be to make dual use of the equipment specified main fans, possibly with attenuators.
to provide smoke control of the common areas. In this way it is
possible to provide a simple and effective cross flow ventilation • Another solution may be to provide active cooling in the
system to extract warm, stale air from these spaces and their corridors using a mechanical shaft ventilation system with
ceiling voids. cooling.
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Colt CoolShaft: providing smoke ventilation • Economical. CoolShaft systems offer cooling that is 4 - 7 times
more economical than conventional air conditioning systems,
and combating overheating in common areas with lower initial costs. CoolShaft runs much of the year in free
of residential buildings cooling mode, with evaporative cooling brought on-line when
temperatures rise.
CoolShaft is a combined smoke and day-to-day shaft system
which uses evaporative cooling technology to provide active pre- • Low energy use. Evaporative cooling is up to 90% efficient.
cooling of the incoming air, without compromising the ability of CoolShaft only needs a small quantity of electricity for the fan
the shaft system to ventilate the common area in a fire – and this that circulates the air and for the water pump.
with exceptionally low energy consumption.
• High cooling capacity. One CoolShaft unit can cool multiple
While a ventilation system supplying untreated outside air is floors, and often the complete building, owing to its inherent
able to achieve temperatures in the corridor at typically 3-5OC high cooling capacity.
above the outside ambient, a CoolShaft system is able to reduce
temperatures to below the outside ambient by providing active • No refrigerants. CoolShaft is free from refrigerants, thus
cooling in the corridors. there are no F gas compliance issues, and there is no need for
refrigerant / water pipework in the building.
Since CoolShaft is a combined smoke and day-to-day shaft system,
our design ensures that if there is a fire there is no compromise • Hygiene certificate. CoolShaft has an integrated water quality
in its ability to ventilate the common area and allow smoke to system using simple and robust technology. It provides safe
escape. circulation with temperature control and regular renewal of
water to avoid the growth of bacteria and scale. It has been
The many benefits of CoolShaft begin with low energy extensively tested and certified hygienically in compliance with
cooling VDI 6022 (“Hygienic Requirements for Ventilation Systems
and Units for Internal Spaces”). This is a rigorous standard for
It doesn’t need to cost the earth to cool a building: using the air conditioning systems and confirms the high quality of supply
cooling power of water, it’s possible to achieve low energy air.
cooling. Here are some of the features and benefits of CoolShaft:
• A space saver. CoolShaft has a smaller rooftop footprint and
• Cooling of corridors. Whereas basic day-to-day ventilation saving on rooftop ductwork compared to conventional air
systems for common corridors and lobbies use outside air to conditioning systems, thereby freeing up space.
ventilate the space, the CoolShaft provides active cooling with
incoming air up to 10OC below ambient temperatures, providing • Lightweight. CoolShaft is more lightweight than conventional
highly desirable conditions for residents. air conditioning systems.
With CoolShaft, the incoming air is pre-cooled A CoolShaft evaporative cooling unit is integrated into the
adiabatically when temperatures reach a set point smoke ventilation shaft plant
Help resources
View our white paper, “Ventilation
solutions for overheated corridors”
for further info.
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Quartermile, Edinburgh Castlegate, Manchester Harrods Apartments, London
Highbury Square, London Junction Apartments, Manchester Olympics Athletes Village, London
Olympics Athletes Village, London St George’s Square, Glasgow Highbury Square, London
Harrods Apartments, London Blenheim Court Student Accommodation, Bristol Southside Apartments, Birmingham
Commissioning and testing
Any mechanical or electrical system needs
commissioning before use and natural
or powered ventilation systems are no
exception.
Colt commissioning engineers will check
the installation, set the equipment to
work and set up the control system to
ensure that everything works correctly
in accordance with the system cause and
effect chart.
Smoke testing of the completed
installation is not part of the normal
commissioning process but may be offered
upon request.
Why choose Colt? You can count on Colt to: Service and maintenance
• We are able to provide all the • Look at the complete picture: we know Our service team offers mechanical
equipment necessary for smoke control how a building works and have and electrical, preventative and reactive
of multi-storey buildings: OVs, AOVs, extensive in-house expertise in a broad service, maintenance and repair for a wide
shaft systems, access hatches, smoke range of technologies. variety of building services equipment,
dampers, smoke door and window whether or not this has been supplied
actuators, smoke detectors, break glass • Design the most cost-effective, by Colt.
switches, and manual and automatic no-nonsense solution engineered to
controls. meet your needs and any prevailing We provide a 24 hour, 365 day
regulations, relying on our in-house emergency cover as standard.
• We can provide a complete package of technical resources such as CAD
scheme design, manufacture, installation, and CFD. Maintenance of a smoke control system
commissioning and maintenance, with is essential. Regular maintenance protects
the advantage that all the components • Advise on the prevailing regulations your investment and brings peace of mind
are contained within one package of and standards. We have the expertise to that the system will operate effectively in
works. deliver smoke control systems that an emergency.
satisfy both the architectural demands
• Every type of building presents different and the safety regulations. British Standard BS 5588-12 and BS9999
dynamics and requirements, and when Customise our products to fit the recommends that smoke control systems
you work with Colt, you can count on exact requirements of your project should be serviced at least once a year
full peace of mind in every phase of the and, where necessary, have them and tested weekly.
project and for the full life cycle of your specially tested at our R&D facility.
system because our experts understand
the engineering and architectural • Supply our high quality products,
challenges of different buildings. manufactured under quality standards
and third party tested to rigorous
standards. Install and commission your
system: our experienced, professional
project management teams will take
care of everything.