NCC 2019 Volume One Amendment 1
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Specification C3.4 Fire doors, smoke doors, fire windows and shutters

Specification C3.4 Fire doors, smoke doors, fire windows and shutters

1. Scope

This Specification sets out requirements for the construction of fire doors, smoke doors, fire windows and fire shutters.

Intent

To prescribe standards for the construction of fire doors, smoke doors, fire windows and fire shutters.

Specification C3.4 contains detailed Deemed-to-Satisfy Provisions that could form part of a solution for achieving the Performance Requirements relevant to:

  • fire doors;
  • smoke doors;
  • fire windows; and
  • fire shutters.

2. Fire Doors

A required fire door must—

(a)

comply with AS 1905.1; and

(b)

not fail by radiation through any glazed part during the period specified for integrity in the required FRL.

Intent

To specify the fire performance of fire doors to achieve compatibility with the fire performance of the walls in which they are located.

Required fire doors must comply with AS 1905.1, which is the construction Standard for fire doors. This Standard in turn requires that fire doors be tested in accordance with AS 1530.4.

If there is any glazing in the door, the door must not fail by radiation through that glazing within the period specified in the door’s FRL criterion of integrity.

In most cases, the BCA requires a fire door to have an FRL of –/60/30. Where a fire door is located in a firewall, a higher FRL is required.

The first criterion of zero minutes is a reference to the structural adequacy of the door. AS 1905.1 does not require a fire door to be tested for structural adequacy.

The final criterion of 30 minutes is a reference to the insulation the door must provide. It is difficult for a fire door to achieve a higher insulation criterion when tested in accordance with AS 1530.4.

Any glass panel in a fire door must not fail through heat radiation during a fire, as measured by the AS 1530.4 test, before the door fails the integrity criterion. If the glass panel fails by radiation, spread of fire could occur due to radiant heat igniting combustible materials.

3. Smoke Doors

Intent

To specify the smoke performance of smoke doors to achieve compatibility with the smoke performance of the walls in which they are located, by minimising the flow of smoke from one side of the door to the other.

Clause 3.1 is a performance criterion for smoke doors. It sets the general requirement that smoke doors must prohibit the passage of smoke from one side to the other; and if glass panels are installed, minimise the risk of injury of people accidentally walking into them. For example, it would generally be acceptable for the panel to be opaque.

To comply with Clause 3.1, a building proponent may choose to comply with Clause 3.2.

Construction deemed-to-satisfy
Intent

To specify the general requirements under the Deemed-to-Satisfy Provisions for the construction of smoke doors.

Under Clause 3.2(a), the leaves of a smoke door which is intended to achieve the requirements of Clause 3.1 must swing in both directions, or in the direction of travel. This means that they cannot be sliding doors or roller shutters.

To make sure that a door is adequately smoke sealed during a fire:

  • the doors must achieve a resistance to smoke at 200°C for 30 minutes. To achieve this, the door leaves can be at least 35 mm thick solid core timber, or of some other construction if the building proponent can satisfy the appropriate authority that it will achieve this;
  • the leaves must be fitted with smoke seals;
  • the door must normally be closed, or automatic-closing;
  • where the door is automatic-closing, it must be activated by smoke detectors which comply with the relevant provisions of AS 1670.1 and are located as specified in Clause 3.2(d)(ii)(A). Under Clause 3.2(d)(ii)(B), the doors release and close in a power failure; and
  • where the doors are opened manually, they must return to the closed position each time they are opened.

Clause 3.2 requires glazing in smoke doors to comply with AS 1288. The glazing must be made apparent by opaque construction if it is capable of being mistaken for an unobstructed opening as part of an exit. This is achieved by complying with the requirements of Clause 3.2(g). The intent of Clause 3.2(g) is not to permit the glazing in smoke doors to be entirely of clear construction.

There is currently some discussion regarding whether or not seals around smoke resistant doors are required to achieve the same resistance to smoke at 200°C in the same manner as the smoke door leaves under Clause 3.2(b)(i). Any queries on this matter should be referred to the State or Territory body responsible for building regulatory matters.

3.1 General requirements

Smoke doors must be constructed so that smoke will not pass from one side of the doorway to the other and, if they are glazed, there is minimal danger of a person being injured by accidentally walking into them.

3.2 Construction Deemed-to-Satisfy

A smoke door of one or two leaves satisfies Clause 3.1 if it is constructed as follows:

(a)

The leaves are side-hung to swing—

(i)

in the direction of egress; or

(ii)

in both directions.

(b)

The leaves are solid-core and at least 35 mm thick, or are capable of resisting smoke at 200°C for 30 minutes.

(c)

The leaves are fitted with smoke seals.

(d)
(i)

The leaves are normally in the closed position; or

(ii)
(A)

The leaves are closed automatically with the automatic closing operation initiated by smoke detectors, installed in accordance with the relevant provisions of AS 1670.1, located on each side of the doorway not more than 1.5 m horizontal distance from the doorway; and

(B)

in the event of power failure to the door, the leaves fail-safe in the closed position.

(e)

The leaves return to the fully closed position after each manual opening.

(f)

Any glazing incorporated in the door complies with AS 1288.

(g)

If a glazed panel is capable of being mistaken for an unobstructed exit, the presence of the glass must be identified by an opaque mid-height band, mid-rail, crash-bar or other opaque construction.

4. Fire Shutters

A required fire shutter must—

(a)

be a shutter that—

(i)

is identical with a tested prototype that has achieved the required FRL; and

(ii)

is installed in the same manner and in an opening that is not larger than the tested prototype; and

(iii)

did not have a rise in average temperature on the side remote from the furnace of more than 140 K during the first 30 minutes of the test; or

(b)

be a steel shutter complying with AS 1905.2 if a metallic fire shutter is not prohibited by C3.5.

Intent

To enable the fire performance of fire shutters to be compatible with the fire performance of the walls in which they are located.

Under Clause 4(a)(i), required fire shutters must have the required FRL determined in accordance with Schedule 5.

Schedule 5 requires that a prototype of the element being tested must be subjected to the Standard Fire Test. See AS 1530.4.

In order for a fire shutter to comply with Specification C3.4, it must be identical to a prototype tested in accordance with AS 1530.4.

When testing the FRL of fire shutters in accordance with AS 1530.4, the structural adequacy criteria is not included. Hence, these criteria are not included in the required FRL of a fire shutter.

Under Clause 4(a), non-metallic fire shutters:

  • must be identical to a prototype tested in accordance with AS 1530.4;
  • must not be larger than the tested prototype; and
  • during the AS 1530.4 testing, the temperature on the non-furnace side of the shutter must not exceed 140 K during the first 30 minutes of the test.

The reason for the last condition is to reduce the amount of radiant heat on the non-fire side of the shutter, which could ignite combustible materials.

Under Clause 4(b), metallic fire shutters can only be used if not prohibited by C3.5. Metallic fire shutters are not permitted in certain situations because of the risk that fire could spread by way of radiated heat facilitated by the metal construction of the shutter. Such radiated heat could ignite combustible materials on the non-fire side of the shutter.

If permitted, metallic fire shutters must either comply with AS 1905.2 or be in accordance with Clause 4(a), in that they:

  • must be identical to a prototype tested in accordance with AS 1530.4;
  • must not be larger than the tested prototype; and
  • during the AS 1530.4 testing, the rise in temperature on the non-furnace side of the shutter must not exceed 140 K during the first 30 minutes of the test.

5. Fire Windows

A required fire window must be—

(a)

identical in construction with a prototype that has achieved the required FRL; and

(b)

installed in the same manner and in an opening that is not larger than the tested prototype.

Intent

To specify the fire performance of fire windows to achieve compatibility with the fire performance of the walls in which they are located.

Required fire windows must have the required FRL determined in accordance with Schedule 5.

Schedule 5 requires that a prototype of the element being tested must be subjected to the Standard Fire Test. See AS 1530.4.

Therefore, in order for a fire window to comply with Specification C3.4, it must be identical to a prototype tested in accordance with AS 1530.4.

When testing the FRL of fire windows in accordance with AS 1530.4, the structural adequacy and insulation criteria are not included. Hence these criteria are not included in the required FRL of a fire window.