Fire safety

Few older houses will meet modern fire safety standards. Renovation provides an opportunity to bring improved fire safety.

Until fairly recently, fire safety was not generally a significant consideration in house design and construction, and some older timber houses are likely to burn readily.

Generally, hard lining with plasterboard reduces the risk of fire spreading within a house but there is still a significant fire load from furnishings.

In any fire, smoke and toxic fumes – not the flames from house fires – generally cause fatalities. Fires from upholstery foam, bedding materials and plastics will smoulder and produce toxic gases but few flames, while fires from burning wood or cooking oil will produce hot, fierce flames. 

Designing for fire safety

The design process of renovations must include fire safety consideration. This may include:

  • installation of smoke alarms (mandatory)
  • installing a fire extinguisher in the kitchen
  • installing heat detectors 
  • consideration of a domestic fire sprinkler system.

Chimneys will also need to be assessed for fire safety if the fireplaces they serve are to be used for heating.

Flat conversions

Fire safety may also be an issue where the villa has been or is being converted into two dwelling units. For original conversions, the work that was done may not have met the fire separation requirements at the time of the conversion, and for new work, the requirements of Building Code clause C Protection from Fire will need to be met.

Heaters and other appliances

All appliances that burn gas, solid fuel or any other combustible material must be installed to ensure that:

  • the combustion process does not raise the temperature of any adjacent building element to a level where its performance is affected 
  • the accumulation of combustion gases within the building is avoided.

You can find guidance in the BRANZ bulletin BU654 Installation and maintenance of solid fuel appliances.

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Smoke alarms

Smoke alarms are a requirement under New Zealand Building Code clause F7 Warning systems. This applies to all existing homes undergoing building work, not just new houses.

Acceptable Solution F7/AS1 requires Type 1 smoke alarms, which must have:

  • a hush button to silence the alarm for at least 60 seconds 
  • a test button 
  • a sound level that complies with NZS 4514:2009 Interconnected smoke alarms for houses – not less than 75 dBA at the sleeping position and not more than 100 dBA at 1.8 m height. (The standard can be downloaded for free.)

On floors with bedrooms the smoke alarms must be located either in every sleeping space or within 3.0 m of every sleeping space door. In this case, the smoke alarms must be audible to sleeping occupants on the other side of the closed doors.

In multi-storey homes there must be at least one smoke alarm on each level, however having an alarm in each sleeping space is considered preferable.

Although there are several types of alarms that can be used to comply with Building Code requirements, Fire and Emergency New Zealand recommends hard-wired alarms or photoelectric alarms with batteries that last up to 10 years.

F7/AS1 does not require smoke alarms in houses to be interconnected, but this is a good idea (and it is a requirement in a part of NZS 4514 that is not referenced). With interconnected alarms, when one smoke alarm detects fire smoke, all alarms will sound. Some models connect wirelessly.

Under the Residential Tenancies (Smoke Alarms and Insulation) Regulations 2016 all rental homes must have smoke alarms:

  • The alarms must be either hard wired or photoelectric battery alarms with a battery life of at least 8 years. 
  • If alarms have a battery, it is the tenant’s responsibility to replace the battery when it is worn out.
  • There must be at least one smoke alarm installed in the sleeping space or within 3 metres of the entrance to the sleeping space. 
  • There must be an alarm on each floor where there is a habitable space however having an alarm within each sleeping space is preferable.

How many alarms?

Fire and Emergency New Zealand recommends installing an alarm in each sleeping and living space and interconnecting them – a sensible approach to ensure full compliance with F7/AS1. New alarms are available that are smaller and more discreet with longer battery life than the older models.

Where to locate alarms

Alarms should ideally be installed on the ceiling, at least 200 mm from a wall or a ceiling beam to avoid dead air space. With sloping ceilings the alarm should be 200–500 mm from the apex.

An alternative (but not preferred) position is high on a wall, at least 100 mm from the ceiling and 600 mm from corners to avoid dead air pockets.

To reduce the risk of false alarms or faults, do not install:

  • in a kitchen, garage or bathroom 
  • near a heat source such as a heat pump or solid fuel burner 
  • in damp or draughty areas. 


Vacuum over smoke alarms to avoid dust build-up, and test with the test button monthly. The smoke detection element can be tested annually with an incense stick. Battery alarms should be replaced every 10 years.

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Domestic sprinklers

Sprinklers provide the most effective protection against fire damage, and systems suitable for domestic installations are available. If a fire starts, the sprinkler heads immediately above the fire will discharge water.

The most common domestic fire sprinkler systems:

  • use a glass bulb, heat-sensitive element 
  • activate at about 68°C 
  • have a flat and wide spray pattern with small and medium droplet sizes 
  • have sprinkler heads that may be concealed, flush-mounted, side-wall or pendant type
  • require a 20 mm diameter pipe connection.

If a fire develops, not all sprinkler heads will operate, but only those closest to the fire – 65% of fires are controlled by a single sprinkler head, and 95% are controlled by five sprinkler heads or less.

When a sprinkler head is set off, the fire brigade is also called.

Installation and maintenance

The design and installation of a domestic sprinkler system must be carried out by a qualified practitioner, with independent inspection and certification.

Maintenance and testing should be in accordance with the relevant standards and in accordance with the manufacturer’s instructions.

(Updated 22 August 2018)