NCC 2019 Volume One Amendment 1
Specification C3.15 Penetration of walls, floors and ceilings by services

Specification C3.15 Penetration of walls, floors and ceilings by services

1. Scope

This Specification prescribes materials and methods of installation for services that penetrate walls, floors and ceilings required to have an FRL.

Specification C3.15 sets out details of permissible service penetrations through walls, floors and ceilings, and was developed using building practices that are in general use. The Specification permits the use of metal pipe systems and conduits (but not flue pipes) which do not satisfy the insulation criteria of AS 1530.4, provided certain criteria are met.

Specification C3.15 does not apply to larger diameter electrical cables (i.e. where the opening is larger than those specified in Clause 5(a) and (b) of 2000 mm2 or 500 mm2). This does not mean that larger diameter electrical cables cannot be approved under C3.15. Larger diameter electrical cables can be approved under C3.15(a)(i) or, if necessary, as a Performance Solution.

2. Application

(a)

This Specification applies to installations permitted under the Deemed-to-Satisfy Provisions of the BCA as alternatives to systems that have been demonstrated by test to fulfil the requirements of C3.15(a).

(b)

This Specification does not apply to installations in ceilings required to have a resistance to the incipient spread of fire nor to the installation of piping that contains or is intended to contain a flammable liquid or gas.

3. Metal pipe systems

(a)

A pipe system comprised entirely of metal (excluding pipe seals or the like) that is not normally filled with liquid must not be located within 100 mm, for a distance of 2 m from the penetration, of any combustible building element or a position where combustible material may be located, and must be constructed of—

(i)

copper alloy or stainless steel with a wall thickness of at least 1 mm; or

(ii)

cast iron or steel (other than stainless steel) with a wall thickness of at least 2 mm.

(b)

An opening for a pipe system comprised entirely of metal (excluding pipe seals or the like) must—

(i)

be neatly formed, cut or drilled; and

(ii)

be no closer than 200 mm to any other service penetration; and

(iii)

accommodate only one pipe.

(c)

A pipe system comprised entirely of metal (excluding pipe seals or the like) must be wrapped but must not be lagged or enclosed in thermal insulation over the length of its penetration of a wall, floor or ceiling unless the lagging or thermal insulation fulfils the requirements of Clause 7.

(d)

The gap between a metal pipe and the wall, floor or ceiling it penetrates must be fire-stopped in accordance with Clause 7.

4. Pipes penetrating sanitary compartments

If a pipe of metal or UPVC penetrates the floor of a sanitary compartment in accordance with C3.15(c)(ii)

(a)

the opening must be neatly formed and no larger than is necessary to accommodate the pipe or fitting; and

(b)

the gap between pipe and floor must be fire-stopped in accordance with Clause 7.

5. Wires and cables

If a wire or cable or cluster of wires or cables penetrates a floor, wall or ceiling—

(a)

the opening must be neatly formed, cut or drilled and no closer than 50 mm to any other service; and

(b)

the opening must be no larger in cross-sectional area than—

(i)

2000 mm2 if only a single cable is accommodated and the gap between cable and wall, floor or ceiling is no wider than 15 mm; or

(ii)

500 mm2 in any other case; and

(c)

the gap between the service and the wall, floor or ceiling must be fire-stopped in accordance with Clause 7.

6. Electrical switches and outlets

If an electrical switch, outlet, socket or the like is accommodated in an opening or recess in a wall, floor or ceiling—

(a)

the opening or recess must not—

(i)

be located opposite any point within 300 mm horizontally or 600 mm vertically of any opening or recess on the opposite side of the wall; or

(ii)

extend beyond half the thickness of the wall; and

(b)

the gap between the service and the wall, floor or ceiling must be fire-stopped in accordance with Clause 7.

7. Fire-stopping

(a)

Material: The material used for the fire-stopping of service penetrations must be concrete, high-temperature mineral fibre, high-temperature ceramic fibre or other material that does not flow at a temperature below 1120°C when tested in accordance with ISO 540, and must have—

(i)

demonstrated in a system tested in accordance with C3.15(a) that it does not impair the fire-resisting performance of the building element in which it is installed; or

(ii)

demonstrated in a test in accordance with (e) that it does not impair the fire-resisting performance of the test slab.

(b)

Installation: Fire-stopping material must be packed into the gap between the service and wall, floor or ceiling in a manner, and compressed to the same degree, as adopted for testing under Clause 7(a)(i) or (ii).

(c)

Hollow construction: If a pipe penetrates a hollow wall (such as a stud wall, a cavity wall or a wall of hollow blockwork) or a hollow floor/ceiling system, the cavity must be so framed and packed with fire-stopping material that is—

(i)

installed in accordance with Clause 7(b) to a thickness of 25 mm all round the service for the full length of the penetration; and

(ii)

restrained, independently of the service, from moving or parting from the surfaces of the service and of the wall, floor or ceiling.

(d)

Recesses: If an electrical switch, socket, outlet or the like is accommodated in a recess in a hollow wall or hollow floor/ceiling system—

(i)

the cavity immediately behind the service must be framed and packed with fire-stopping material in accordance with Clause 7(c); or

(ii)

the back and sides of the service must be protected with refractory lining board identical with and to the same thickness as that in which the service is installed.

(e)

Test: The test to demonstrate compliance of a fire-stopping material with this Specification must be conducted as follows:

(i)

The test specimen must comprise a concrete slab not less than 1 m square and not more than 100 mm thick, and appropriately reinforced if necessary for structural adequacy during manufacture, transport and testing.

(ii)

The slab must have a hole 50 mm in diameter through the centre and the hole must be packed with the fire-stopping material.

(iii)

The slab must be conditioned in accordance with AS 1530.4.

(iv)

Two thermocouples complying with AS 1530.4 must be attached to the upper surface of the packing each about 5 mm from its centre.

(v)

The slab must be tested on flat generally in accordance with Section 10 of AS 1530.4 and must achieve an FRL of 60/60/60 or as otherwise required.