NCC 2019 Volume Two Amendment 1
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Part 3.7.5 Smoke alarms and evacuation lighting
Appropriate Performance Requirements
Appropriate Performance Requirements
Where an alternative smoke alarm or lighting to assist evacuation system is proposed as a Performance Solution to that described in Part 3.7.5, that proposal must comply with—
- Performance RequirementP2.3.2; and
- the relevant Performance Requirements determined in accordance with A2.2(3) and A2.4(3) as applicable.
3.7.5.1 Application
(a)
Compliance with this acceptable construction practice satisfies Performance Requirement P2.3.2 for smoke alarms.
(b)
For the purposes of this Part, a Class 1 building includes a Class 10a private garage located above or below the Class 1 building.
3.7.5.2 Smoke alarm requirements
Smoke alarms must—
(a)
(b)
comply with AS 3786, except that in a Class 10a private garage where the use of the area is likely to result in smoke alarms causing spurious signals, any other alarm deemed suitable in accordance with AS 1670.1 may be installed provided that smoke alarms complying with AS 3786 are installed elsewhere in the Class 1 building; and
(c)
be powered from the consumer mains source where a consumer mains source is supplied to the building; and
(d)
be interconnected where there is more than one alarm.
Explanatory information:
Explanatory information:
A smoke alarm can give spurious alarms if the atmosphere contains particles which obscure vision, such as could occur in a Class 10a private garage part of a building. 3.7.5.2(b) therefore allows the use of a more suitable alarm, such as a heat alarm, in these locations.
3.7.5.2(d) requires alarms to be interconnected where there is more than one alarm. This only applies within a single dwelling. Therefore, alarms in a Class 1a dwelling need not be interconnected with alarms in another dwelling or a private garage which does not belong to the Class 1a dwelling.
State and Territory Variations
State and Territory Variations
In New South Wales delete 3.7.5.2 insert NSW 3.7.5.2 as follows:
- Smoke alarms must—
- be located in—
- comply with AS 3786, except that in a Class 10a private garage where the use of the area is likely to result in smoke alarms causing spurious signals, any other alarm deemed suitable in accordance with AS 1670.1 may be installed provided that smoke alarms complying AS 3786 are installed elsewhere in the Class 1 building; and
- be connected to the consumer mains power where consumer power is supplied to the building; and
- be interconnected where there is more than one alarm.
- Heat alarms must be installed in a Class 10a private garage that is located beneath a Class 1a dwelling and not associated with that dwelling, in accordance with NSW 1.1.4.
Explanatory information:
Explanatory information:
A smoke alarm can give spurious alarms if the atmosphere contains particles which obscure vision, such as could occur in a Class 10a private garage part of a building. NSW 3.7.5.2(a)(ii) therefore allows the use of a more suitable alarm, such as a heat alarm, in these locations.
NSW 3.7.5.2(a)(iv)requires alarms to be interconnected where there is more than one alarm. This only applies within a single dwelling. Therefore alarms in a Class 1a dwelling need not be interconnected with alarms in another dwelling.
Where a Class 10a private garage is located beneath a Class 1a dwelling and is not associated with that dwelling, NSW 3.7.5.2(b) requires a heat alarm to be provided in the non-associated Class 10a private garage in accordance with NSW 1.1.4 in the NSW Additions. The NSW Addition also contains requirements for the interconnection of alarms and the provision of durable notices.
3.7.5.3 Location — Class 1a buildings
In a Class 1a building, smoke alarms must be located in—
(a)
any storey containing bedrooms, every corridor or hallway associated with a bedroom, or if there is no corridor or hallway, in an area between the bedrooms and the remainder of the building; and
(b)
each other storey not containing bedrooms.
(see Figure 3.7.5.1, Diagram a and b)
3.7.5.4 Location — Class 1b buildings
In a Class 1b building, smoke alarms must be located in—
(a)
every bedroom; and
(b)
every corridor or hallway associated with a bedroom, or if there is no corridor or hallway, in an area between the bedrooms and the remainder of the building; and
(c)
each other storey.
(see Figure 3.7.5.1, Diagram c)
Figure 3.7.5.1
Diagram a Class 1a building where all bedrooms are grouped together and served by a hallway
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Smoke alarm |
Legend for Figure 3.7.5.1 Diagram b:
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Smoke alarm |
Diagram c Class 1b building where multiple bedrooms are served by a hallway
Legend for Figure 3.7.5.1 Diagram c:
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Smoke alarm |
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Smoke alarm with evacuation lighting (as requiredby 3.7.5.6(b)(i)) |
3.7.5.5 Installation of smoke alarms
Smoke alarms required by 3.7.5.3 and 3.7.5.4 must be installed on or near the ceiling, in accordance with the following:
(a)
Where a smoke alarm is located on the ceiling it must be—
(i)
a minimum of 300 mm away from the corner junction of the wall and ceiling; and
(ii)
between 500 mm and 1500 mm away from the high point and apexes of the ceiling, if the room has a sloping ceiling.
(b)
Where (a) is not possible, the smoke alarm may be installed on the wall, and located a minimum of 300 mm and a maximum of 500 mm off the ceiling at the junction with the wall.
Explanatory information:
Explanatory information:
Smoke alarms need to be located on (or near) the ceiling for optimum detection of smoke in a fire situation with special care taken to avoid dead air spaces. A dead air space is an area in which trapped hot air will prevent smoke from reaching the alarm. This space generally occurs at the apex of cathedral ceilings, the corner junction of walls and ceilings and between exposed joists etc. (see diagram 1).
Smoke alarms may be located on the wall in accordance with 3.7.5.5(b). Diagram 1 provides location criteria and the dimensional relationship to building elements and the associated dead air spaces.
3.7.5.6 Lighting to assist evacuation — Class 1b buildings
In a Class 1b building, a system of lighting must be installed to assist evacuation of occupants in the event of a fire, and—
(a)
be activated by the smoke alarm required by 3.7.5.4(b); and
(b)
consist of—
(i)
a light incorporated within the smoke alarm; or
(ii)
the lighting located in the corridor, hallway or area served by the smoke alarm.
Explanatory information:
Explanatory information:
The lighting required by 3.7.5.6 may consist of artificial lighting which may already be installed in a corridor, hallway or area, provided that the lighting is activated by the smoke alarm. However consideration should be given to ensure that the lighting is not controlled by a dimmer or timer controlled switch which may dim the level of light to an ineffective level, or switch the light off before occupants have time to evacuate.
1. Smoke alarms general requirements:
Performance RequirementP2.3.2 and the Deemed-to-Satisfy Provisions of this Part require automatic warning on the detection of smoke in buildings, so that occupants may be alerted to a fire in order to evacuate to a place of safety.
2. Different smoke alarm requirements for Class 1a and Class 1b buildings:
Part 3.7.5 specifies different smoke alarm requirements for Class 1a and Class 1b buildings. The main difference is that a Class 1b building is required to have a greater number of smoke alarms, i.e. smoke alarms must be installed in all bedrooms, and a system of lighting must be installed to assist evacuation. This is due to Class 1b buildings generally being used for more transient purposes and the occupants being less familiar with the building layout.
3. Smoke alarms complying with AS 3786:
3.7.5.2(b) requires a smoke alarm(s) to comply with AS 3786. AS 3786 contains the requirements for the design and performance of electrically operated smoke alarms containing both detection and alarm facilities. Types of smoke alarms prescribed in AS 3786 include photoelectric, ionisation or a combination of the two.
4. Smoke alarms to be connected to consumer mains source:
3.7.5.2(c) requires that a smoke alarm be connected to the consumer mains electricity source where a consumer mains source is supplied to the building. A smoke alarm complying with AS 3786, that is intended for connection to an external power source, is required to be provided with a secondary power source i.e. a source of power to supply the smoke alarm in the event that the primary power source is unavailable. Generally, the requirement is met by providing mains powered smoke alarms with a battery back up.
5. Interconnection of smoke alarms:
3.7.5.2(d) requires that alarms be interconnected to provide a common alarm so that if one alarm in the dwelling activates, the other alarms automatically activate, which will increase the likelihood of sleeping occupants becoming aware of the detection of smoke. Alarms of a Class 1 building need not be interconnected with alarms in another Class 1 building or a private garage which does not belong to the Class 1 building.
6. Location of smoke alarms:
When deciding on the position of smoke alarms it is important to remember that they are intended to detect smoke before it reaches the sleeping occupants of a building.
The ensuing alarm is designed to wake the occupants and give them time to evacuate the building.
7. Smoke alarms required on other storeys not containing bedrooms:
In addition to a smoke alarm being required to be provided on storeys containing bedrooms, a smoke alarm is also required on each other storey that is not already provided with a smoke alarm even if those storeys consist of only carparking, bathrooms, laundries and the like. "Storey" in this context differs from the definition contained in NCC Volume One which excludes such spaces from being considered as storeys.
Reference to "storey" only applies within a single dwelling. For example, if a storey contains a private garage belonging to the Class 1a dwelling in addition to a private garage which does not belong to the Class 1a dwelling, smoke alarms must be installed in both private garages.
Where the other storey is a Class 10a private garage, 3.7.5.2(b) permits the use of any other alarm deemed suitable in accordance with AS 1670.1 provided smoke alarms complying with AS 3786 are installed elsewhere in the Class 1 building.
8. Nuisance alarms:
Smoke alarms are extremely sensitive and may detect smoke and moisture created by common household activities such as burnt toast or steam from a bathroom.
Accordingly, to reduce the likelihood of nuisance alarms, it is preferable that smoke alarms are not located near cooking appliances and bathrooms. However, if it is necessary to locate alarms in these positions, the type of alarm installed may need to be considered as some alarm types may be more suitable in certain locations.
9. Added flexibility when considering smoke alarm location:
The options described in Deemed-to-Satisfy Provisions are not the only means available for complying with the Housing Provisions. The performance nature of the NCC provides flexibility to develop alternative methods if it is preferred to meet the Performance Requirement in some other way. This added flexibility may be utilised when considering the location of smoke alarms.