Openings for pipes
10.5Pipes which pass through a fire-separating element (unless the pipe is in a protected shaft), should meet the appropriate provisions in alternatives A, B or C below.
Alternative A: Proprietary seals (any pipe diameter)
10.6Provide a proprietary sealing system which has been shown by test to maintain the fire resistance of the wall, floor or cavity barrier.
Alternative B: Pipes with a restricted diameter
10.7Where a proprietary sealing system is not used, fire-stopping may be used around the pipe, keeping the opening as small as possible. The nominal internal diameter of the pipe should not be more than the relevant dimension given in Table 14.
The diameters given in Table 14 for pipes of specification (b) used in situation (2) assumes that the pipes are part of an above ground drainage system and are enclosed as shown in Diagram 38 if they are not, the smaller diameter given for situation (3) should be used.
Alternative C: Sleeving
10.8A pipe of lead, aluminium, aluminium alloy, fibre-cement or uPVC, with a maximum nominal internal diameter of 160mm, may be used with a sleeving of non-combustible pipe as shown in Diagram 37. The specification for non-combustible and uPVC pipes is given in the notes to Table 14
Ventilation ducts, flues etc.
10.9Where air handling ducts pass through fire separating elements the integrity of those elements should be maintained.
There are three basic methods and these are:
- Method 1 Protection using fire dampers;
- Method 2 Protection using fire-resisting enclosures;
- Method 3 Protection using fire-resisting ductwork.
10.10Method 1 is not suitable for extract ductwork serving kitchens. This is due to the likely build up of grease within the duct which can adversely affect the effectiveness of any dampers.
Further information on fire-resisting ductwork is given in the ASFP Blue Book: Fire resistng ductwork (ISBN: 1 87040 926 4) published by the Association for Specialist Fire Protection and freely available from the ASFP website at www.asfp.org.uk.
10.11Fire dampers should be situated within the thickness of the fire-separating elements and be securely fixed. It is also necessary to ensure that, in a fire, expansion of the ductwork would not push the fire damper through the structure.
10.12Adequate means of access should be provided to allow inspection, testing and maintenance of both the fire damper and its actuating mechanism.
10.13Where the use of the building involves a sleeping risk, such as an hotel or residential care home, fire dampers should be actuated by smoke detector-controlled automatic release mechanisms, in addition to being actuated by thermally actuated devices.
However, in a situation where all occupants of the building can be expected to make an unaided escape and an L1 fire alarm system is installed in accordance with BS 5839-1:2002, the following exceptions may be made:
- aIf, on the detection of smoke, the alarm system signals the immediate evacuation of all the occupants of the building, then fire/smoke dampers are not needed; and
- bIf the building is divided into fire compartments and the alarm system is arranged to signal the immediate evacuation of the occupants of the fire compartment in which the fire has been detected, then smoke detector operated fire/smoke dampers need only be provided where ductwork enters or leaves the fire compartment.
Notes:Fire dampers actuated only by fusible links are not suitable for protecting escape routes. However an ES classified fire and smoke damper which is activated by a suitable fire detection system may be used. See paragraph 10.15.
10.14Further guidance on the design and installation of mechanical ventilation and air- conditioning plant is given in BS 5720:1979 on ventilation and air-conditioning ductwork in BS 5588-9:1999.
Further information on fire and smoke-resisting dampers is given in the ASFP Grey Book: Fire and smoke resiting dampers’ (ISBN: 1 87040 924 8) published by the Association for Specialist Fire Protection and freely available from the ASFP website at www.asfp.org.uk.
10.15Fire dampers should be tested to BS EN 1366-2:1999 and be classified to BS EN 13501-3:2005. They should have an E classification equal to, or greater than, 60 minutes. Fire and smoke dampers should also be tested to BS EN 1366-2:1999 and be classified to BS EN 13501-3. They should have an ES classification equal to, or greater than, 60 minutes.
Notes:Fire dampers tested using ad-hoc procedures based on BS 476 may only be appropriate for fan-off situations. In all cases, fire dampers should be installed as tested.
Paragraphs 5.46 and 8.40 also deal with ventilation and air-conditioning ducts.
10.16If a flue, or duct containing flues or appliance ventilation duct(s), passes through a compartment wall or compartment floor, or is built into a compartment wall, each wall of the flue or duct should have a fire resistance of at least half that of the wall or floor in order to prevent the by-passing of the compartmentation (see Diagram 39).
10.17In addition to any other provisions in this document for fire-stopping:
- ajoints between fire-separating elements should be fire-stopped; and
- ball openings for pipes, ducts, conduits or cables to pass through any part of a fire- separating element should be:
- ikept as few in number as possible; and
- iikept as small as practicable; and
- iiifire-stopped (which in the case of a pipe or duct, should allow thermal movement).
10.18To prevent displacement, materials used for fire-stopping should be reinforced with (or supported by) materials of limited combustibility in the following circumstances:
- ain all cases where the unsupported span is greater than 100mm; and
- bin any other case where non-rigid materials are used (unless they have been shown to be satisfactory by test).
10.19Proprietary fire-stopping and sealing systems (including those designed for service penetrations) which have been shown by test to maintain the fire resistance of the wall or other element, are available and may be used.
Other fire-stopping materials include:
- cement mortar;
- gypsum-based plaster;
- cement-based or gypsum-based vermiculite/ perlite mixes;
- glass fibre, crushed rock, blast furnace slag or ceramic-based products (with or without
resin binders); and
- intumescent mastics.
These may be used in situations appropriate to the particular material. Not all of them will be suitable in every situation.
Guidance on the process of design, installation and maintenance of passive fire protection is available in Ensuring best practice for passive fire protection in buildings (ISBN: 1 87040 919 1) produced by the Association for Specialist Fire Protection (ASFP).
Further information on the generic types of systems available, information about their suitability for different applications and guidance on test methods is given in the ASFP Red Book: Fire Stopping and Penetration Seals for the Construction Industry – the ‘Red Book’ (ISBN: 1 87040 923 X) published by the Association for Specialist Fire Protection and freely available from the ASFP website at www.asfp.org.uk.