Health and Safety
Taking care with power tools and ladders, and dealing with such hazards as asbestos, lead paint and mould.
Fire Control
Flames aren’t the only part of a house fires which can injure or kill people. Smoke released from fires is toxic and can also kill. It has higher concentrations of carbon monoxide than air, and lower levels of oxygen.
Some fires – for example, ones from upholstery foam, bedding materials and plastics – smoulder and produce toxic gases but not flames. Other fires – for example, from burning wood or cooking oil – produce hot, fierce flames.
Consideration of fire safety, smoke alarm installation and possible residential sprinkler specification are part of the design process.
Smoke alarm types
Smoke alarms detect the smoke particles from a fire. The two most common types are:
- ionisation smoke alarm – a radioactive source ionises air, creating an electric current flow which is then inhibited by the smoke particles
- photo-electric smoke alarm – a small light beam is deflected by the smoke particles into a photocell.
Both types detect smoke from hot flaming fires well. The ionisation alarm is slower to detect smouldering fires. This is a problem as they tend to be cheaper and are more commonly installed.
The New Zealand Building Code requires ‘type 1’ smoke alarms to be fitted in all residential buildings. ‘Type 1’ smoke alarms have:
- a hush button so the alarm can be cleared without shutting off power (for example, removing the battery)
- a test button.
Battery-powered smoke alarms are acceptable and are commonly installed. There are few available hard-wired systems available for domestic situations, although small office installations can and have been adapted for domestic use.
Where to install smoke alarms
Smoke alarms should be installed on or near the ceiling, and in accordance with the manufacturer’s instructions. At minimum, they must be installed within 3 metres of any sleeping space door. The NZ Fire Service recommends installing them in every sleeping and living space.
To be effective, any installed smoke alarm must be audible through closed doors, operating properly, and able to detect smoke from all types of fires.
- Larger homes
At least two smoke alarms will be needed in an extended plan home.
- Separated sleeping areas
At least two smoke alarms will be needed if there is more than one sleeping area.
- Placement of smoke alarms
If you’re placing a smoke alarm in a hallway, it should be between living areas and sleeping areas.
- More than one storey
If a home has more than one storey, there should be a smoke alarm on every level.
Fire detectors
Fire detectors are mainly activated by heat. Smoke alarms provide earlier warning that a fire has broken out, so are preferable.
Sprinklers
Sprinklers are 90 to 95% reliable in preventing fires from getting out of control. They react to heat in the surrounding air.
The most common domestic fire sprinkler systems:
- use a glass bulb, heat-sensitive element
- activate at about 68C
- have a flat and wide spray pattern with small and medium droplet sizes
- have sprinkler heads that may be either concealed, flush-mounted, side-wall or pendant
- need a 20 mm diameter pipe connection.
Heaters and other appliances
All appliances that burn gas, oil, solid fuel or any other combustible material have to be installed to ensure that:
- the combustion process does not raise the temperature of any neighbouring building element to a level where its performance is affected
- the accumulation of combustion gases within the building is avoided (see passive ventilation and mechanical ventilation).