Part C3 Protection of openings

See Deemed-to-Satisfy Provisions for C1. The same applies here.

Openings listed in C3.1(a) need not comply with the Deemed-to-Satisfy Provisions of Part C3.

However, for the purposes of C3.1(a)(iv) multiple storeys within a carpark connected by openings formed by a vehicle ramp are considered to be within the same fire compartment and therefore sprinkler protection may be required under E1.5.

Openings listed in C3.1(b) and (c) must comply with the relevant Part C3 Deemed-to-Satisfy Provisions.

C3.2 applies to all Class 2–9 buildings, even those protected by a sprinkler system. The provisions only apply to openings which are exposed to a fire source feature (i.e. an allotment boundary or another building on the same allotment) and which are located in an external wall required to have an FRL (see Figure C3.2).

Any openings in the external walls of buildings separated by fire walls must comply with C3.2. In this case, each building is a fire-source feature to the other building (see Figure C3.2).

Openings in an external wall must be protected if within 3 metres of a side or rear boundary (see C3.2(a)(i)). Or, under C3.2(a)(ii), if they are within 6 metres of the far boundary of an adjoining road, etc, if the opening is located in a storey above, or a reasonable distance from ground level. Openings must also be protected if they are within 6 metres of another non-Class 10 building on the allotment (see C3.2(a)(iii)).

In regards to the protection of openings under C3.2(a), an assessment is required to determine a “reasonable” distance from ground level, on a case by case basis. Discussions with the appropriate authority may be required in this regard.

Figure C3.2 Plan showing when C3.2 requires protection of openings in an external wall required to have an FRL

Under C3.2(b), openings in an external wall must be limited to the size specified, if the openings are required to be protected under C3.2(a). This is unless the openings are in a Class 9b open spectator stand.

Figure C3.3 illustrates the use of Table C3.3.

When the walls are at an angle of 180º or greater, the distance between them may be zero because the effects of radiant heat between the walls is negligible. In practice, the distance between such walls is likely to equal the width of the fire wall.

Sole-occupancy units in Class 2 and Class 3 buildings are not fire compartments to which C3.3 applies.

Figure C3.3 Plan showing illustration of Table C3.3

C3.3 applies to both external walls. It does not apply to fire walls separating fire compartments. (A fire wall is not always an internal wall. See Figure C2.7(3) of this Guide).

C3.4(a) applies where protection is required to doorways, windows and other openings.

C3.4(b) requires fire doors, fire windows and fire shutters to comply with Specification C3.4.

C3.4 is referred to by a number of the BCA’s Deemed-to-Satisfy Provisions. Some of these provisions will specify whether or not a required sprinkler system must be internal or external. Where external wall wetting sprinklers are proposed, it may be designed using AS 2118.2, even though that Australian Standard is not referenced in the BCA. Please note that there are certain limitations that apply to AS 2118.2, such as the types of glazing applicable and location of sprinkler heads.

C3.4(a)(i) clarifies that wall-wetting sprinklers are only to be used with doors that are self-closing or automatic closing.

C3.4(a)(ii) clarifies that wall-wetting sprinklers are only to be used with automatic closing windows or permanently closed windows.

For openings other than doorways or windows, C3.4(a)(iii)(A) clarifies that internal or external wall-wetting sprinklers are not recognised as an acceptable method of protection for voids under the Deemed-to-Satisfy Provisions. Conventional wall-wetting sprinklers need a medium or surface to act on. An opening consisting of a void does not provide such a medium or surface.

If the opening in the fire wall is for a horizontal exit, refer to C3.7.

When a doorway is installed in a fire wall, to achieve the same fire separation as the wall, C3.5(a) allows the use of:

• two fire doors, one on each side of the doorway;
• two fire shutters, one on each side of the doorway;
• one fire door and one fire shutter, one on each side of the doorway;
• a single fire door; or
• a single fire shutter.

(See C3.5(a)(i), C3.5(a)(ii) and C3.5(a)(iii))

In each option, the single fire door or shutter, or any of the combinations of the two, must have the same fire-resistance level (FRL) as the fire wall. (This is except for the insulation criterion, which must be at least 30 minutes)

When determining the required FRL of the fire door or shutter, Clause 6 of Schedule 5 states that non-loadbearing elements need not comply with the structural adequacy criterion. A fire door or shutter is normally regarded as a non-loadbearing element.

C3.5(b) states that any fire door or shutter required under C3.5(a) must be either self-closing or automatic-closing. If automatic closing, it must be initiated by smoke detectors, or (in specified circumstances) any other detector deemed suitable in accordance with AS 1670.1 (see C3.5(c)). It is important that the detector used is suitable for the location and type of fire likely to occur. The suitability of detectors can be determined by reference to AS 1670.1. These detectors must also be in accord with the relevant provisions of AS 1670.1, and located as specified in C3.5(c).

Under C3.5(d), the activation of any other required suitable fire alarm system (including a complying sprinkler system), in either of the fire compartments separated by the fire wall, must operate the automatic closing of the fire door or shutter.

A smoke detector can give false alarms if the atmosphere contains particles such as steam or other vapours that obscure vision (eg kitchens, carparks, etc). If a smoke detector is likely to give a false alarm due to the atmospheric conditions, then a heat detector should be used to comply with C3.5(c).

Figure C3.5 illustrates the requirements of C3.5.

Figure C3.5 Plan illustrating automatic fire doors or automatic fire shutters installed in an opening in a fire wall in accordance with C3.5

It is an acceptable and frequently used option to protect an opening in a fire wall by a sliding fire door held open by an electromagnetic device. However, sliding fire doors tend to be quite large and heavy, presenting a potential danger to occupants passing through while it is closing. To reduce the danger to building occupants the rate of the door’s closing is limited and must be by the deactivation of an electromagnetic device (see C3.6(a)(i)).

In the event of a power failure, the electromagnetic device must also fail-safe so that the door closes thereby maintaining the integrity of the fire wall (see C3.6(a)(ii)).

Warning lights and signs are required to be installed on each side of the door by C3.6(a)(iii) and (iv) to indicate the presence and operation of the fire door. C3.6(b) and (c) requires the electromagnetic device to deactivate and the warning system to operate when there is a fire in a fire compartment on either side of the fire wall. This process must be activated by either smoke detectors or heat detectors (in specific circumstances) installed in accordance with the relevant provisions of AS/NZS 1905.1 and AS 1670.1 (see C3.6(b)).

The activation of any other required suitable fire alarm system (including a complying sprinkler system) in either of the fire compartments must also cause the automatic closing of the fire door (see C3.6(c)).

A smoke detector can give false alarms (see comments on C3.5). Heat detectors complying with C3.6(b) should be used in these circumstances.

The use of fire shutters are prohibited in a horizontal exit by D2.19(b)(ii). Similarly, D2.19(b)(iii) does not permit sliding doors to be used as horizontal exits.

There are some concessions to these prohibitions (see D2.19).

The fire doors used for horizontal exits, as referred to in C3.7, must swing in the direction of travel (as required by D2.20).

If the horizontal exit applies in both directions (i.e. the doorway may be used to escape from either fire compartment to the other), the installation of two doors may be necessary (see Figure C3.7).

Unless it is located in a Class 7 or Class 8 building, a doorway which is part of a horizontal exit must be protected by a single fire door complying with C3.7(a)(i).

The reason for allowing two fire doors to be installed in a doorway in Class 7 and Class 8 buildings is because single fire doors with the required fire-resistance level (FRL) are heavy and difficult to open. In combination, the two fire doors must achieve an equivalent FRL to the fire wall.

If two fire doors are installed in a doorway in a Class 7 or Class 8 building, it may be necessary to install a small lobby to allow for the swing of the doors (see Figure C3.7).

C3.7(b) has the same requirements for fire doors as C3.5. Refer to the comments made in C3.5 for application to C3.7(a).

Figure C3.7 Plans showing horizontal exits in a fire wall

Any doorway leading into a fire-isolated exit is a possible source of fire and/or smoke spreading into that exit. The spread of fire or smoke into a fire-isolated exit is dangerous.

It is therefore important that such doorways are protected by fire doors. These fire doors must be self-closing (see C3.8(a)) or automatic-closing initiated by smoke detectors or (in specified circumstances) heat detectors (see C3.8(b)).

C3.8 has the same requirements for fire doors or shutters as C3.5. Refer to the comments made in C3.5 for application here.

C3.8 does not apply to a doorway leading from a fire-isolated exit to a road or open space, because failure of such a doorway is not affected by a fire in the building. However, note that such a doorway may require protection to comply with C3.2.

C3.8(d) only applies to a window which could expose an evacuating person or fire fighter to radiant heat from a fire in the building. Therefore, C3.8(d) does not apply to a window exposed to another window within the same fire-isolated exit.

If a sprinkler system is chosen as the means of protection in accordance with C3.4, the sprinkler heads must be located on the side of the window outside the exit.

A window subject to the requirements of C3.8(d) may also require protection from an external fire to comply with C3.2.

C3.9 minimises the number of service penetrations into a fire-isolated exit by only allowing the services specified. Each of the services listed in C3.9(a) and (b) is essential to maintain a safe environment within the fire-isolated enclosure.

Under C3.9(c), the water supply for fire-fighting may be located within a fire-isolated exit. Hydrants located within a fire-isolated enclosure allow the fire brigade to set up their hoses and other equipment in a protected area before attacking the fire.

The location of any service penetrations into the fire-isolated exit permitted by C3.9 must not reduce the exit width required by D1.6.

C3.9 should be read in conjunction with D2.7, which deals more generally with installations in exits and paths of travel.

Any doorway leading into a fire-isolated lift shaft could assist the spread of fire. Any spread of fire into the shaft could endanger the lives and safety of the people using the lift, and lead to the spread of fire to another part of the building. Therefore, it is important that such doorways be protected by fire doors.

AS 1530.4 (the Australian Standard for the Standard Fire Test) requires lift landing doors to be tested for integrity. Such doors are usually of metal construction, and are not required to satisfy any insulation criteria.

Lift indicator panels in excess of 35 000 mm² are considered to represent a sufficient risk of spreading fire into a lift shaft. Indicator panels exceeding this size require backing by material having a fire-resistance level (FRL) of –/60/60.

Small panels of 35 000 mm² or less are unlikely to lead to the spread of fire into the shaft. This exemption is similar in principle to those allowed by C3.1 for minor openings such as control joints, weep holes, subfloor ventilators and the like.

To maintain the fire performance of walls surrounding a sole-occupancy unit and corridors used as egress routes in Class 2 and Class 3 buildings, C3.11(a) and (b) requires the following doorways to be protected:

• between sole-occupancy units and any public corridor, public hallway or the like (see C3.11(a)(i));
• between sole-occupancy units and any room not within a sole-occupancy unit, such as a common laundry, common sitting room and the like (see C3.11(a)(ii));
• between sole-occupancy units and any landing of an internal, non-fire-isolated stair serving as a required exit (see C3.11(a)(iii));
• between sole-occupancy units (see C3.11(a)(iv));
• between a room not in a sole-occupancy unit (such as a common laundry, common sitting room and the like) and any public corridor, public hallway or the like (see C3.11(b)(i)); and
• between a room not in a sole-occupancy unit (such as a common laundry, common sitting room and the like) and any landing of an internal, non-fire-isolated stair serving as a required exit (see C3.11(b)(ii)).

To maintain the fire performance of walls surrounding a sole-occupancy unit in a Class 4 part of a building, C3.11(c) requires the doorways to the unit to be protected.

The degree of fire protection required by C3.11(d) for doorways to sole-occupancy units in Class 2 and Class 3 buildings and Class 4 parts is dependant upon the types of construction.

C3.11(d)(i) applies to all Class 2 and Class 3 buildings and Class 4 parts in buildings of Type A construction, except those Class 3 buildings specified in C3.11(d)(iii).

C3.11(d)(ii) applies to all Class 2 and Class 3 buildings and Class 4 parts in buildings of Type B or Type C construction, except those Class 3 buildings specified in C3.11(d)(iii).

C3.11(d)(iii)(A) or (B) only applies to Class 3 residential care buildings fitted with a sprinkler system complying with Specification E1.5. A Class 3 residential aged care building that does not meet these requirements, must comply with C3.11(d)(i) or (ii) as applicable.

C3.11(d)(ii) requires that the door be self-closing to make sure that the door is closed during a fire. The requirement for such doors to be self-closing does not apply to a Class 3 residential aged care building which meets the requirements of C3.11(d)(iii)(A).

Under C3.11(e), openings other than doorways in internal walls which are required to have a fire-resistance level (FRL) for integrity and insulation are permitted only if they do not lower the wall’s fire-resisting performance.

Doors required by C3.11(d) may be automatic-closing, initiated by smoke detectors or (in specified circumstances) any other detector deemed suitable in accordance with AS 1670.1(see C3.11(f)(i)). The suitability of detectors can be determined by reference to AS 1670.1. Refer to C3.5 for door operation requirements as they apply to doors under C3.11.

C3.11(g) applies, in a Class 2 or Class 3 building only, where a path of travel is along an open balcony, landing or the like and it does not provide a person evacuating with a choice of travel in different directions to alternative exits. If this path of travel passes an external wall of another sole-occupancy unit (see C3.11(g)(i)) or a room which is not within a sole-occupancy unit (see C3.11(g)(ii)), the external wall must be constructed in accordance with C3.11(g)(iii), have any doorways protected in accordance with C3.11(g)(iv), and any window or other openings protected in accordance with C3.11(g)(v)(A) or (B).

The reason for the above construction is to provide building occupants trying to evacuate with protection from radiant heat and flames whilst passing the unit that is on fire.

C3.12 applies to floors and ceilings in buildings of Type A, B and C construction.

The performance of a fire resisting element may be compromised if service penetrations are not adequately protected. The method of protection should ensure the fire resisting capabilities of the element being penetrated is maintained. In buildings of Type A construction, the service may be within a fire resisting shaft or protected in accordance with C3.15. In buildings of Type B and C construction the service may be within a shaft that does not reduce the fire resistance of the element it penetrates or it must be protected in accordance with C3.15.

C3.13 only applies to buildings of Type A construction, because the other types of construction do not require service shaft walls to have a fire-resistance level (FRL).

C3.13 sets out the detail of the protection required in different circumstances to prevent the spread of fire from one floor to another floor by way of a shaft.

In BCA 1990, this provision was performance-based. In subsequent editions of the BCA the provision is covered by the Performance Requirements. C3.14 has been left blank, rather than renumber subsequent clauses.

C3.15 sets out a number of requirements for protection of service openings. These include:

• The use of tested prototypes in accordance with AS 4072.1 and AS 1530.4 (see C3.15(a)).
• Ventilation and air-conditioning ducts complying with AS 1668.1 (see C3.15(b)).
• The use of Specification C3.15 for metal pipes systems (excluding pipe seals or the like), sanitary plumbing, wire or cable, or clusters of wires or cables, electrical switches, or outlets or the like.

C3.15 considers the protection of openings in elements that are providing a barrier to the spread of fire and are thus required to have an FRL. The elements of an FRL that provide the barrier to spread of fire are insulation and integrity and that protecting an opening in an element an FRL for structural adequacy is unnecessary. For this reason, C3.15 only applies to an element required to have an FRL with respect to integrity or insulation.

C3.15(a)(i) quite clearly permits the use of tested systems. To comply with this Deemed-to-Satisfy Provision it is necessary for the appropriate authority to be satisfied that the proposal is identical to a tested prototype. AS 1530.4 includes a number of methods of reporting the test results. These include—

• a test report.

• a regulatory information report.

• a test certificate.

Only the test report and regulatory information report contain sufficient information to allow the appropriate authority to be satisfied that the proposal is identical with the tested prototype or differs from the prototype in accordance with AS 4072.1.

It should be noted that the provision only applies to the service where it penetrates the building element. Although AS 4072.1 and AS 1530.4 requires a tested penetration to extend a specified distance beyond the penetration opening for the purpose of carrying out the test, the NCC only requires the building element and the part of the service penetrating that element to be identical with the tested prototype or differs from the prototype in accordance with AS 4072.1.

C3.15(a)(ii) allows a concession from the insulation criteria of a tested prototype specified in C3.15(a)(i). The concession only applies for penetrations by metal piping systems where the service pipe is not located within an exit (see C3.15(a)(ii)(D)) and is at least 100 mm from any combustible building element for a distance of 2 m from the penetration of the building element (see C3.15(a)(ii)(B)). To ensure that fire is not spread via the conduction of heat from the metal pipe, it is important that the service pipe be located so that combustible material cannot be located within 100 mm of the pipe for a distance of 2 m from the penetration (see C3.15(a)(ii)(C)). One method of achieving this would be to place a guard around the pipe.

In the case of a floor waste, it would not be possible to ensure that no combustible material is located within 100 mm of it. Therefore, C3.15(a)(ii) is unlikely to apply to floor wastes.

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 2 000 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)(A) (i.e. a tested system), C3.15(a)(i)(B) where in accordance with AS 4072.1, or if necessary, as a Performance Solution.

Gas pipes can be approved under C3.15(a) or, if necessary, as a Performance Solution.

To avoid the spread of fire between fire compartments or to another building, construction joints between building elements are normally packed with fire retardant material.

A number of proprietary products are suitable for this purpose, having previously been tested in accordance with AS 1530.4 to demonstrate they have achieved the required fire-resistance level (FRL). The test only needs to record the failure criteria of integrity and insulation. C3.16 does not require structural adequacy criteria to be achieved, as it is not part of the AS 1530.4 test for these types of materials.

If lightweight fire protection has been inadequately applied to a column, there is an increased risk that the column will transmit heat to another building element (such as a floor or ceiling) through which it passes. The effect is that the column can cause a reduction in the fire-resistance level (FRL) or resistance to the incipient spread of fire of the elements through which it passes. This can result in the spread of fire. To eliminate this potential problem, it is necessary to use a system tested in accordance with AS 1530.4.