Chemical fire retardants

Chemical fire retardants help delay or prevent combustion, but there are potential health and environmental issues around the use and production of the chemicals, and the cost or possible harms of chemical fire retardants need to be weighed up against the benefits.

Rights: The University of Waikato Te Whare Wānanga o Waikato

Burning combustion-modified foam

Chemical fire retardants can help delay or prevent combustion. In this sofa, chemical retardants have been added to create combustion-modified foam. This slows down the burning, as ignition of the foam is difficult.

Why do we need retardants?

Fire is unpredictable, can be very fast and can lead to flashover effects, and people often don’t get the time to get out.

Chemical fire retardants can be added to foams and fabrics (known as combustion-modified foams and fabrics) that are used in the production of furniture. Chemical fire retardants slow combustion and save lives by giving people the time they need to evacuate.

How chemical fire retardants work

Different chemicals delay combustion in different ways:

• Some chemical fire retardants interrupt the chemical reaction in the gas phase of combustion (e.g. halon and phostrex).
• Some chemical fire retardants break down the polymers in the solid phase of combustion so that they melt and flow away from the flame.
• Other solid phase chemical fire retardants cause a layer of carbon char to form on a polymer surface. The carbon char layer is very difficult to burn.
• Intumescents are materials that contain chemicals that cause swelling up behind the protective char layer, providing even more insulation.

Potential problems with chemical fire retardants

There is concern that the production of chemical fire retardants can result in risk to human health and the environment. Studies have shown that some toxic chemicals have been found in human tissue and in the environment where the chemicals are produced (they are not produced in New Zealand). There is concern about human contact during the production of the chemicals and over the disposal of waste products.

When used in furniture:

• some of the chemicals are toxic and may be dangerous for small children who might suck on furniture
• some scientists wonder if the chemicals will affect the performance (comfort) of the furniture
• some scientists have expressed concern that fumes may be emitted from the retardant chemicals even without a fire
• smoke from burning furniture is toxic, and some argue that chemical fire retardants may add to that toxicity
• adding chemicals to furniture will make the furniture expensive. (People will have a choice between furniture with chemical fire retardants and without. The furniture without chemical fire retardants looks the same and is made of the same materials but is less expensive.)

Making a decision

Scientists have to weigh up the benefits against the costs and possible harms of using combustion-modified foams and fabrics. The benefits include the possibility of saving lives and buildings through the use of chemical fire retardants, causing slower burning and difficult ignition.

Presently, New Zealand does import some combustion-modified foams, but it’s not a requirement for people to have them in their homes.

Rights: 123RF Limited

Aircraft seats

There is a requirement for all aircraft seats to be treated with chemical fire retardants but there is currently no regulation in New Zealand to have furniture treated with chemical fire retardants.

Seats used in aircraft are regulated in New Zealand and are treated with chemical fire retardants.

All furniture in the United Kingdom (UK) is regulated, both in homes and in workplaces.

There is an ongoing debate in the United States about the regulation of furniture. Many fire scientists and firefighters want furniture regulated, but furniture companies do not. They are afraid that the higher prices will stop people buying their furniture. Some people are concerned about possible health and environmental issues.