Specification 7 Fire hazard properties

It should be noted that C2D11 requires the fire hazard properties of linings, materials and assemblies used in the construction of a building to comply with Specification 7. Specification 7 sets out the details of these requirements.

Table S7C2 sets out which clauses of Specification 7 linings, materials and assemblies must comply with.

S7C3(a) states that a floor lining or covering must have a critical radiant flux not less than that in Table S7C3. A material’s critical radiant flux is determined by testing the material in accordance with AS ISO 9239.1. This test is the floor radiant panel test. The higher a material’s critical radiant flux is, the better the material performs.

The different requirements for materials are based on the building classification, the location of the material in the building and whether the building contains a sprinkler system. The requirements are higher for aged care buildings and health care buildings due to the limited mobility of occupants in those buildings. The requirements are based on research which indicated that the required egress time in these buildings was greater and therefore proposed levels of control needed to be greater.

S7C3(b) contains requirements dealing with a material’s smoke development rate. A material’s smoke development rate is determined by testing the material in accordance with AS ISO 9239.1. This test is the floor radiant panel test. The requirement is only applicable where floor materials and coverings are installed in buildings that do not have a sprinkler system complying with Specification 17. S7C3(b) limits the smoke development rate to not more than 750 percent-minutes.

Table S7C3 does not contain any requirements for Class 9c buildings that do not contain a sprinkler system. The reason for this is because, pursuant to E1D10, all Class 9c buildings must have a sprinkler system installed throughout the building.

S7C4 specifies that a material used as a wall or ceiling lining must be a Group 1, Group 2 or Group 3 material and used in accordance with Table S7C4. A material’s group number is determined by testing the material in accordance with AS 5637.1.

For the purpose of the BCA, a Group 1 material indicates the best performing material and a Group 4 material is the worst performing material.

The allowable material group number differences are based on the building classification and the location of the material in the building. It is also dependent on whether the building contains a sprinkler system (other than a FPAA101D or FPAA101H system) in accordance with Specification 17, and whether the material is used as a wall lining or a ceiling lining.

The locations within the building referred to in Table S7C4 are fire-isolated exits, fire control rooms, public corridors, specific areas and other areas. The definition of specific areas differs according to the use of the building. The specific areas are as follows:

• for Class 2 and 3 buildings, a sole-occupancy unit;
• for Class 5 buildings, open plan offices with a minimum floor dimension/floor to ceiling height ratio >5;
• for Class 6 buildings, shops or other buildings with a minimum floor dimension/floor to ceiling height ratio >5;
• for Class 9a health care buildings, patient care areas;
• for Class 9b theatres and halls, etc, an auditorium;
• for Class 9b schools, a classroom; and
• for Class 9c buildings, resident use areas.

For Class 5 and 6 buildings, the minimum floor dimension and the floor to ceiling height need to be considered when determining “specific areas”. An area is a specific area if the minimum floor dimension/floor to ceiling height ratio is more than 5.

“Other areas” are areas which are not either a fire-isolated exit, a public corridor or a “specific area”.

The requirements differ between the building classifications. These requirements are based on research which indicated that the required egress time differed between the building’s classifications and therefore proposed levels of control needed to be greater.

S7C4(1) contains requirements dealing with a material’s smoke development rate. The requirements only apply where the wall and/or ceiling lining material is installed in a building that does not have a sprinkler system complying with Specification 17 (other than a FPAA101D or FPAA101H system).

Examples

Consider the case of a Class 5 building having a 15 m by 20 m open plan office with a ceiling height of 2.5 m. The building also contains an enclosed office having a floor plan of 3 m by 4 m.

For the open plan office area, as the minimum floor dimension (15 m) divided by the ceiling height (2.5 m) is 6, i.e. more than 5, it would be deemed a “specific area” and therefore wall and ceiling linings in the area would need to comply with the requirements for Class 5 “specific areas”.\

For the enclosed office, as the minimum floor dimension (3 m) divided by the ceiling height (2.5 m) is 1.2, i.e. less than 5, it would not be deemed to be a “specific area” and therefore wall and ceiling linings in the enclosed office would need to comply with the requirements for Class 5 “other areas”.

Air-handling ductwork has the potential to cause the rapid spread of fire throughout a building. It is important that the materials used in its construction are appropriate to avoid this potentially dangerous situation. The particular requirements are covered by AS 4254.

Lift cars are small, enclosed spaces, with minimal ventilation and no active fire suppression equipment. They also have no immediate means of egress. The materials used in their construction must be appropriate to avoid a potentially dangerous situation.

Floor linings and floor coverings must have a critical radiant flux of not less than 2.2, and the wall linings and ceiling linings must be either a Group 1 material or a Group 2 material, which are similar to those required in public corridors.

S7C7 sets out requirements for materials and assemblies not included elsewhere in Specification 7. The detail is located in Table S7C7. It is important to read the notes to this table because they contain specific requirements.

Fire-isolated exits and fire control rooms

Because fire-isolated exits are considered a safe place for people seeking egress during a fire, it is acknowledged that they should be as safe as possible.

Similarly, fire control rooms are part of a building set aside for the fire brigade to co-ordinate its search, rescue and firefighting operations during a fire. Since fire control rooms are used by the fire brigade during a fire, they should also be a safe as possible.

An aim of Table S7C7 is to minimise the risk of a fire in a fire-isolated exit and a fire control room.

It could be claimed that fire is unlikely to enter either of these spaces because of their construction and protection, and therefore there is no need for control of the finishes within them. However, compromising the integrity of these spaces is not at all unusual. For example, by —

• removal, alteration or deterioration of fire doors; or
• wedging open fire doors in fire-isolated stairways

The prescribed Spread-of-Flame Index and Smoke-Developed Index measures aim to limit finishes to those that are no more hazardous than a conventional paint finish on a non-combustible surface.

The requirements for sarking-type materials in a fire-isolated exit or fire control room are contained under the heading of sarking-type material.

Class 9b theatres, public halls and the like

To minimise the spread of fire and smoke in a Class 9b building used as a theatre, public hall or the like, Table S7C7 contains specific requirements for —

• fixed seating used by the audience; and
• proscenium curtains.

Escalators, non-required non fire-isolated stairways and ramps, etc.

Table S7C4 contains requirements for materials not listed elsewhere in Specification 7, used in stairways, ramps and escalators not required by the BCA, and which are non fire-isolated. These requirements aim to prevent the spread of fire through an unrestricted number of floors through unprotected openings for stairways, ramps and escalators. Further requirements for escalators, non-required non fire-isolated stairways and ramps can be found in D2D17 and Specification 14.

Sarking-type material

The requirements in Table S7C7 for a sarking-type material, in areas other than fire-isolated exits and fire control rooms, to have a Flammability Index of not more than 5 is to minimise the risk of sarking facilitating the spread of fire.

As explained above, fire-isolated exits are considered a safe place for people seeking egress during a fire. Likewise, fire control rooms are spaces used by the fire brigade during a fire. Accordingly, both spaces should be as safe as possible and the required Flammability Index is more restrictive.

Other materials

The other materials referred to in Table S7C7 are materials not referred to in other parts of Specification 7 and elsewhere in Table S7C7. Such materials include, but are not limited to the following:

• Window frames other than timber window frames (timber window frames are exempt from the requirements of Specification 7, see C2D11(3)).
• Attachments to walls, floors and ceilings.