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The interpretation and application of Cl.3.3 shall be as follows:

a. Subject to the provisions of Cl.3.3.1b. and any other expressed provision to the contrary, any reference to a building of which an element of structure forms a part means the building or (if the building is divided into compartments) any compartment of the building, for which the element forms a part.

b. Any reference to height means the height of a building, but if any part of the building is completely separated throughout its height both above and below ground from all other parts by a compartment wall or compartment walls in the same continuous vertical plane, any reference to height in relation to that part means the height solely of that part.

c. If any element of structure forms part of more than one building or compartment and the requirements of fire resistance specified in Table 3.3A, in respect of one building or compartment, and differs from those specified in respect of any other building or compartment of which the element forms a part, such element shall be so constructed as to comply with the greater or greatest of the requirements specified.

d. If any element of structure is required to be of non-combustible construction, the measure of fire resistance rating shall be determined by the part which is constructed wholly of non-combustible materials. (With the exception of fire protecting suspended ceilings, surface materials for walls and ceilings and floor finishes can be combustible, if they are not relied on to contribute to the fire resistance of the wall or floor).

The requirement on fire resistance in Cl.3.3.2 for non-load-bearing external walls shall not apply to:

a. any part of any external wall which is non-load-bearing and can, in accordance with Cl.3.5 be an unprotected area, or

b. steel structures of a standalone car park for passenger vehicles of Class 3 and below (unladen weight not exceeding 2500kg) provided the following conditions are fulfilled:

(1) Each storey shall be provided with cross ventilation by the provision of uninterrupted openings evenly distributed around the perimeter walls, excluding perimeter walls to air well. The area of the openings shall not be less than 50% of all external walls or 15% of the footprint per storey, whichever is greater. This condition is not applicable if a sprinkler system is installed throughout the car park.

(2) No point on any storey shall be more than 12m from the external air or air well. An air well, where provided for this purpose, shall have a superficial plan area of not less than 10m², or 0.1m² for every 300mm of height, whichever is greater, and have a minimum dimension on plan of 2m, open vertically to the sky for its full height. This condition is not applicable if a sprinkler system is installed throughout the car park.

(3) All floor beams shall be designed as a composite structure with the floor slab.

(4) The building is not more than 24m in habitable height, and there shall not be any basement storeys;

(5) No other usages, other than the electrical services that serve only the car park, are permitted;

(6) Steel structures shall meet the specifications of SS EN 1993-1-2 and SS EN 1994-1-2.

In the case of a single storey building or a building consisting of a first storey and one or more basement storeys, the requirement on fire resistance in Cl.3.3.2 shall not apply to any element of structure which forms part of the first storey and consists of:

a. a structural frame or a beam or column, provided that any beam or column (whether or not it forms part of a structural frame) which is within or forms part of a wall, and any column which gives support to a wall or gallery, shall have fire resistance of not less than the minimum period, if any, required by this Code for that wall or gallery, or

b. an internal load-bearing wall or a load-bearing part of a wall, unless that wall or part of it forms part of a compartment wall or a separating wall, or forms part of the structure enclosing a protected shaft or supports a gallery, or

c. part of an external wall which does not support a gallery and which may, in accordance with Cl.3.5 be an unprotected area.

In determining the fire resistance of floors, no account shall be taken of any fire resistance attributable to any suspended ceiling unless the ceiling is constructed specifically as a fire protecting suspended ceiling, and the construction complies with the requirements under Table 3.3B for Limitations on Fire Protecting Suspended Ceilings.

a. Fire-rated boards are permitted to be used for protection to structural steel beams, columns and as wall construction in building if all of the following are complied with:

(1) The fire-rated boards shall be non-combustible (BS 476 Part 4 or Part 11).

(2) They shall have fire resistance for not less than the relevant period specified in Table 3.3A, with regards to the purpose group of the building of which it forms a part and the dimensions specified in that table.

(3) They shall meet the criteria, in terms of water absorption and bending strength performance, when subject to the test standards of BS EN 520 (for gypsum plaster board) or ISO 1896 (for calcium silicate or cement board).

(4) Fire-rated boards used to make dry walls shall, in terms of impact & deflection performance, meet the partition grade specified under BS 9999 (Test for partitions) in accordance with BS 5234-2.

(5) They shall not be used to protect structural steel in areas which are subject to explosion risk, as the boards may be displaced by the force of the blast.

(6) In buildings under PG VI and VIII, where the presence of corrosive atmosphere may affect the effectiveness of fire-rated boards for protection to structural steel members of buildings, such proposals shall be subject to evaluation of the SCDF.

b. Incorporation of services within fire-rated drywall construction shall comply with the following:

(1) The installations shall meet the fire performance test requirements set out in BS 476 Part 22 and shall not incorporate services beyond the case scenario for which it has been successfully tested.

(2) Electrical cables shall be housed in metal conduits within the dry construction.

(3) Gas pipe installation are prohibited in fire-rated dry construction.