Risk Matters - October 2017

FIRES AND explosions represent a serious threat to the safety of people and properties. One measure that can help in mitigating fires and their consequences is the assurance of using materials that are treated with flame retardants. 

Flame retardants are a key component in reducing the devastating impact of fires on people, property and the environment. It is reported that the use of these compounds saved lives, increased the escape time for families and increased the available response time for the arrival of fire personnel

They are added to different materials or applied as a treatment to materials (e.g. textiles, plastics) to prevent fires from starting, limit the spread of fire and minimize fire damage. Bromine, phosphorus, nitrogen and chlorine are commonly used in flame retardants. Inorganic compounds are also used in flame retardants, either alone or as part of a flame retardant system in conjunction with bromine, phosphorus or nitrogen.

Flame retardants work to stop or delay fire, but, depending on their chemical makeup, they interact at different stages of the fire cycle. The fire cycle is as follows:

• Initial ignition source can be any energy source (e.g. heat, incandescent material, a small flame);
• Ignition source causes the material to burn and decompose (pyrolysis), releasing flammable gases;
• If solid materials do not break down into gases, they remain in a condensed phase. During this phase, they will slowly smolder and, often, self-extinguish, especially if they “char,” meaning the material creates a carbonated barrier between the flame and the underlying material; and
• In the gas phase, flammable gases released from the material are mixed with oxygen from the air. In the combustion zone, or the burning phase, fuel, oxygen and free radicals combine to create chemical reactions that cause visible flames to appear. The fire then becomes self-sustaining because, as it continues to burn the material, more flammable gases are released, feeding the combustion process.

When flame retardants are present in the material, they can act in three key ways to stop the burning process. They may work to disrupt the combustion stage of a fire cycle, including avoiding or delaying “flashover,” or the burst of flames that engulfs a room and makes it much more difficult to escape. They can also limit the process of decomposition by physically insulating the available fuel sources from the material source with a fire-resisting “char” layer. Retardants can also dilute the flammable gases and oxygen concentrations in the flame formation zone by emitting water, nitrogen or other inert gases.

Flame retardants are used predominantly in four major areas, which include Electronics, building and construction materials, furniture and transportation vehicles.

Electronics and Electrical Devices would include items such as televisions, computers and laptops, including monitors, keyboards and portable digital devices and electronic circuit boards. Whereas, building materials would include insulation materials and roofing components.

Using components and structures that are treated with flame retardants should be considered at any or all of the following phases design, material selection, installation, firefighting suppression systems and emergency planning. 

In many sectors such as aviation use of materials that have flame retardant in airplanes is compulsory. Thus, other sectors may adopt the same philosophy as reasonable as practicable. 

Abdullatif Albitawi is the IIRSM branch treasurer in the United Arab Emirates

For more information, visit www.iirsm.org