Diagram 30a (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 limited-combustibility. Can panels with combustible thermosetting cores be used instead?

Diagram 30a applies a more onerous standard than Diagram 30b, any combustible (including thermosetting) core panels should incorporate a band of material of limited combustibility 300mm wide centred over the wall.

However, an alternative approach might be to use a panel system which has been shown in a large-scale test to resist internal and external surface flaming and concealed burning.

Diagram 30b (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 limited-combustibility. Can panels with combustible thermosetting cores be used instead?

In low-rise residential, office or assembly buildings to which Diagram 30b applies, panels with thermosetting cores can be used without any additional protection.

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.

Are lift landing doors which have been tested and classified in accordance with the European standard EN 81-58 an adequate alternative to Doors tested and classified to BS 476 part 23?

The Department has commissioned some comparative testing of doors using these two standards. The conclusions of this work are that for the purposes of Item 2.d of Table B1(provisions for fire doors) of Approved Document B (Vol2), results from EN 81-58 tests can be accepted as equivalent to BS 476 part 22. In due course, the Department intends to publish the report from this work and amendments to the Approved Document necessary to meet the requirements of the Lifts Directive.

Is it acceptable for a 120mm uPVC stack pipe to pass through a floor between an attached garage with a room above without being enclosed in a 30 minute fire-resisting casing?

Item 2 of Table 3 (Maximum nominal internal diameter of pipes passing through fire separating element) now makes it clear that a uPVC pipe, up to 110mm in diameter, can pass through a wall or floor separating a dwellinghouse from an integral garage. The pipe should, however, still be fire stopped in accordance with paragraph 7.8. This would involve sealing around the pipe where it penetrates the wall or floor using a suitable material or a proprietary system as described in Paragraph 7.14.

Does the inclusion of fire suppression systems in Requirement B3(3) mean that all buildings should have a sprinkler system fitted?

No. Requirement B3(3) requires, where reasonably necessary, subdivision of the building with fire-resisting construction and/or the installation of a suitable automatic fire suppression system.

What is considered reasonable in any particular case will depend on the size and intended use of the building. In some cases, either sprinklers or compartment walls and floors will be necessary and other cases it may be necessary to provide both or neither. Guidance on where sprinklers should be provided is given the Approved Document.

Should a fire alarm be provided throughout a block of flats?

The guidance in B1 Section 1 of the Approved Document (fire alarm and fire detection systems) is not intended to be applied to the common parts of blocks of flats and does not include a provision to interconnect installations in separate flats.

Fire detection devices may need to be provided in some blocks to actuate automatic smoke control systems in the common parts of the building in accordance with paragraph 2.25. Such devices are not expected to be linked to a common alarm system.

With reference to the guidance on loft conversions, when providing new fire resisting doors in an existing dwelling house, is it also necessary to replace the existing internal door frames?

A fire-resisting door 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 doors 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 sealed and the operating gap between the door and the frame should be kept to a minimum (usually 3-4mm).