Health Safety Executive
These frequently asked questions (FAQs) refer to the Fire safety: Approved Document B.
Requirement B1 Means of Warning and Escape
1. Paragraph 1.1 in Volume 1 of Approved Document B recommends all new dwellinghouses should be provided with smoke alarms in accordance with the BS 5839-6 to at least a Grade D2 Category LD3 standard. However, table 1 of BS 5839-6:2019 recommends Grade D1 Category LD2?
For the purposes of Part B of the Building Regulations a Grade D2 Category LD3 system is considered to be adequate. Therefore, as a minimum, the system itself should be designed and installed in accordance with the guidance for a Grade D2 LD3 systems in BS 5839-6:2019.
2. Now that door closers are no longer necessary within dwellinghouses do I need them in an HMO?
The Housing Act 2004 replaced the previous housing fitness standard with a statutory framework for assessing and tackling hazards in housing - including fire hazards. Within a house designated as a House in Multiple Occupation such devices may still need to be provided between the private areas (i.e., bedrooms) and the common parts (i.e., circulation spaces, living room, kitchen etc). Further guidance on fire safety provision can be found in the Local Authorities Coordinators of Regulatory Services (LACORS) guide titled Guidance on fire safety provisions for certain types of existing housing.
3. When providing a protected stairway in a dwellinghouse, do I need to fit fire doorsets on the cupboards and bathrooms?
A protected stairway should be enclosed with fire resisting construction and fire doorsets in order to protect people escaping down the stairs from a fire in the accommodation. It may not always be necessary to provide fire doorsets on cupboards if they are small and the fire risk is low. An alternative to providing a fire doorset on a bathroom is to include the bathroom within the stair enclosure, thus removing the need for a fire doorset.
4. When providing new fire doorsets in an existing dwellinghouse as part of a loft conversion, is it also necessary to replace the existing internal door frames?
Guidance on loft conversions is provided in Volume 1 of Approved Document B.
A fire doorset should be regarded as a complete installed assembly. Thus, the door, the frame and any ironmongery should be considered when assessing its suitability. In most cases, however, it should be possible to retain the existing frame. If in doubt, the test report for the door being installed will include details of the door frame in which it was tested. Fire doorsets are often thicker and much heavier than other internal doors. Where existing frames are retained, it may be necessary to replace or relocate the door stops and to install additional fixings back to the structure. The joint between the frame and the surrounding structure should be adequately fire stopped and the operating gap between the door and the frame should be kept to a minimum (usually 3-4mm).
5. For small blocks of flats with no common lobbies, are door closers required for the protected entrance halls?
Door closers are not required for internal fire doorsets in flats, when they are being used to provide lobby protection for a common stair. However, the recommendation for the provision of fire doorsets remains as does the advice to householders that doors should be kept shut, especially at night.
6. Why do we say 1 bed and not 1 person for care homes?
Paragraph 2.43 in Volume 2 of Approved Document B states; Bedrooms should not contain more thanone single or double bed. This is for a design, without sprinklers, relying upon fire resisting construction to protect occupants that are remote from the seat of fire. Research on sprinkler effectiveness in care homes has shown people who are in intimate contact with a fire, for example where clothing or bed linen is alight, are unlikely to benefit from the operation of sprinklers. However, where sprinklers are provided, people who may be in the same room but not in intimate contact with the fire (for instance in another bed) will have an increased chance of survival. It is not the intention of the Approved Document to separate couples who happen to live in a care home by insisting that they sleep in separate beds.
Requirement B3 Internal Fire Spread (Structure)
7. Diagrams 5.2a (Junction of compartment wall with roof) (Volume 1) and 8.2a (Volume 2) (Junction of compartment wall with roof) places restrictions on double skinned insulated roof sheeting, asking for the provision of a 300mm band of material of class A2 s-3, d2. Can panels with combustible thermosetting cores be used instead?
Diagrams 5.2a (Volume 1) and 8.2a (Volume 2) of Approved Document B apply a more onerous standard than Diagrams 5.2b and 8.2b, any combustible (including thermosetting) core panels should incorporate a band of material rated A2 -s3, d2 or better 300mm wide centred over the wall.
8. Diagram 5.2b (Volume 1) and 8.2b (Volume 2) of Approved Document B (Junction of compartment wall with roof) places restrictions on double skinned insulated roof sheeting with a thermoplastic core, asking for the provision of a 300mm band of material of class A2 -s3, d2. material of limited combustibility. Can panels with combustible thermosetting cores be used instead?
In low-rise residential, office or assembly buildings to which Diagram 5.2b (Volume 1) and 8.2b (Volume 2) applies, panels with thermosetting cores can be used without a 300mm band of material A2 s-3, d2 material. However, fire-stopping must be provided to seal the joint between the compartment wall and the underside of the panel. Any voids above the panel (such as where an additional roof covering is provided) should also be adequately fire-stopped.
9. If an existing single storey shop is extended so that it exceeds the maximum 2000m2 compartment size, is it necessary to install a sprinkler system?
Regulation 4 (1) of the Building Regulations 2010 states that building work should comply with the applicable requirements contained in Schedule 1. Regulation 4(3) then goes on to state that after the work is completed the building as a whole should comply with the applicable requirements of Schedule 1 or, where the building did not previously comply with any such requirement, is no more unsatisfactory in relation to that requirement than before the work was carried out.
Where an existing shop is extended such that the final floor area is greater than 2000m2 (whether it exceeded this value previously or not) then the building as a whole may be less satisfactory in relation to Schedule 1 requirement B3(3) than before the work was carried out. Therefore, the building would have to be either subdivided to limit the compartment size, fitted with sprinklers or some other solution would be necessary in order to satisfy regulation 4(3) in relation to requirement B3. Regulation 4(3) must be judged against the requirements set out in Schedule 1 rather than the Approved Document. B3(3) requires sub-division of the building to an extent appropriate to its size and intended use and it may be that some buildings will still comply with requirement B3(3) by virtue of its intended use even though they have been extended without further compartmentation
10. If I provide sprinklers in a block of flats, can I reduce other fire protection measures?
This would be a matter for the designer and the relevant building control body to consider. However, any such proposal may result in the need to upgrade the specification of the sprinkler system and the duration of water supplies.