Section 4: Wall and ceiling linings
Classification of linings
4.1 The surface linings of walls and ceilings should meet the classifications in Table 4.1.
Walls
4.2 For the purposes of this requirement, a wall includes both of the following.
a. The internal surface of internal and external glazing (except glazing in doors).
b. Any part of a ceiling which slopes at an angle greater than 70 degrees to the horizontal.
4.3 For the purposes of this requirement, a wall does not include any of the following.
a. Doors and door frames.
b. Window frames and frames in which glazing is fitted.
c. Architraves, cover moulds, picture rails, skirtings and similar narrow members.
d. Fireplace surrounds, mantle shelves and fitted furniture.
4.4 Parts of walls in rooms may be of lower performance than stated in Table 4.1, but no worse than class D-s3, d2. In any one room, the total area of lower performance wall lining should be less than an area equivalent to half of the room’s floor area, up to a maximum of 20m2 of wall lining.
Ceilings
4.5 For the purposes of this requirement, a ceiling includes all of the following.
a. Glazed surfaces.
b. Any part of a wall at 70 degrees or less to the horizontal.
c. The underside of a gallery.
d. The underside of a roof exposed to the room below.
4.6 For the purposes of this requirement, a ceiling does not include any of the following.
a. Trap doors and their frames.
b. The frames of windows or rooflights and frames in which glazing is fitted.
c. Architraves, cover moulds, picture rails, exposed beams and similar narrow members.
Rooflights
4.7 Rooflights should meet the following classifications, according to material. No guidance for European fire test performance is currently available, because there is no generally accepted test and classification procedure.
a. Non-plastic rooflights should meet the relevant classification in Table 4.1.
b. Plastic rooflights, if the limitations in Table 4.2 and Table 12.2 are observed, should be a minimum class D-s3, d2 rating. Otherwise they should meet the relevant classification in Table 4.1.
Special applications
4.8 Any flexible membrane covering a structure, other than an air-supported structure, should comply with Appendix A of BS 7157.
4.9 Guidance on the use of PTFE-based materials for tension-membrane roofs and structures is given in the BRE report BR 274.
Fire behaviour of insulating core panels used internally
4.10 Insulating core panels consist of an inner core of insulation sandwiched between, and bonded to, a membrane, such as galvanised steel or aluminium.
Where they are used internally they can present particular problems with regard to fire spread and should meet all of the following conditions.
a. Panels should be sealed to prevent exposure of the core to a fire. This includes at joints and where services penetrate the panel.
b. In high fire risk areas, such as kitchens, places of special fire hazard, or in proximity to where hot works occur, only class A1 cored panels should be used.
c. Fixing systems for all panels should be designed to take account of the potential for the panel to delaminate. For instance, where panels are used to form a suspended ceiling, the fixing should pass through the panel and support it from the lower face.
Other controls on internal surface properties
4.11 Guidance on the control of flame spread is given in the following sections.
a. Stairs and landings: Sections 2 and 3 (escape stairs) and Section 15 (firefighting shafts).
b. Exposed surfaces above fire-protecting suspended ceilings: Section 8.
c. Enclosures to above-ground drainage system pipes: Section 9.
Thermoplastic materials
General provisions
4.12 Thermoplastic materials that do not meet the classifications in Table 4.1 can be used as described in paragraphs 4.13 to 4.17. No guidance for European fire test performance is currently available, because there is no generally accepted test and classification procedure.
Thermoplastic materials are defined in Appendix B, paragraph B11. Classifications used here are explained in paragraph B13.
Windows
4.13 Thermoplastic material classified as a TP(a) rigid product may be used to glaze external windows to rooms, but not external windows to circulation spaces. Approved Document K includes guidance on the safety of glazing.
Rooflights
4.14 In rooms and circulation spaces other than protected stairways, rooflights may be constructed of thermoplastic material if they comply with both of the following.
a. The lower surface is classified as TP(a) rigid or TP(b).
b. The size and location of the rooflights follow the limits in Table 4.2, Table 12.2 and Table 12.3.
Lighting diffusers
4.15 The following paragraphs apply to lighting diffusers forming part of a ceiling. Diffusers may be part of a luminaire or used below sources of light. The following paragraphs do not apply to diffusers of light fittings attached to the soffit of a ceiling or suspended beneath a ceiling (Diagram 4.1).
Diagram 4.1 Lighting diffuser in relation to ceiling
4.16 Diffusers constructed of thermoplastic material may be incorporated in ceilings to rooms and circulation spaces, but not to protected stairways, if both the following conditions are met.
a. Except for the upper surfaces of the thermoplastic panels, wall and ceiling surfaces exposed in the space above the suspended ceiling should comply with paragraph 4.1.
b. Diffusers should be classified as one of the following.
i. TP(a) rigid – no restrictions on their extent.
ii. TP(b) – limited in their extent (see Table 4.2 and Diagram 4.2).
Suspended or stretched skin ceilings
4.17 A ceiling constructed from TP(a) flexible panels should meet the following conditions.
a. Have a maximum area of 5m2.
b. Be supported on all sides.
Diagram 4.2 Layout restrictions on class D-s3, d2 plastic rooflights, TP(b) rooflights and TP(b) lighting diffusers
Table 4.2 Limitations applied to thermoplastic rooflights and lighting diffusers in suspended ceilings and class D-s3, d2 plastic rooflights
Diagram 4.3 Layout restrictions on small class D-s3, d2 plastic rooflights, TP(b) rooflights and TP(b) lighting diffusers
Requirement B3: Internal fire spread (structure)
These sections deal with the following requirement from Part B of Schedule 1 to the Building Regulations 2010.
Requirement
Internal fire spread (structure)
B3. (1) The building shall be designed and constructed so that, in the event of fire, its stability will be maintained for a reasonable period
(2) A wall common to two or more buildings shall be designed and constructed so that it adequately resists the spread of fire between those buildings. For the purposes of this sub-paragraph a house in a terrace and a semi-detached house are each to be treated as a separate building.
(3) Where reasonably necessary to inhibit the spread of fire within the building, measures shall be taken, to an extent appropriate to the size and intended use of the building, comprising either or both of the following—
(a) sub-division of the building with fire-resisting construction;
(b) installation of suitable automatic fire suppression systems.
(4) The building shall be designed and constructed so that the unseen spread of fire and smoke within concealed spaces in its structure and fabric is inhibited.
Limits on application
Requirement B3(3) does not apply to material alterations to any prison provided under section 33 of the Prison Act 1952.
Intention
Requirement B3(3) does not apply to material alterations to any prison provided under section 33 of the Prison Act 1952.
In the Secretary of State’s view, requirement B3 is met by achieving all of the following.
a. For defined periods, loadbearing elements of structure withstand the effects of fire without loss of stability.
b. Compartmentation of buildings by fire resisting construction elements.
c. Automatic fire suppression is provided where it is necessary.
d. Protection of openings in fire-separating elements to maintain continuity of the fire separation.
e. Inhibition of the unseen spread of fire and smoke in cavities, in order to reduce the risk of structural failure and spread of fire and smoke, where they pose a threat to the safety of people in and around the building.
The extent to which any of these measures are necessary is dependent on the use of the building and, in some cases, its size, and on the location of the elements of construction.
