There is widespread recognition that foam fire-suppression systems are an invaluable weapon in the armoury of facility operators as they seek to prevent and kill off serious fires.
Nevertheless, selecting the appropriate types of foam and discharge services is crucial for the best results.
Understanding the options with discharge services
Foam fire-suppression systems are usually deployed at sites such as petrochemical plants, aircraft hangars and warehouses where there is a significant risk from flammable or combustible liquids.
The ability to not only extinguish fires, but also smother flames in a way that prevents reignition, makes foam the suppression solution of choice. The key difference with foam systems and other traditional wet-sprinkler systems is the addition of the foaming agent, which is generally stored separately from the water and the two are mixed within the piping system before discharge.
After a facility has been evaluated for its fire risks, either an ‘aspirating’ or ‘non-aspirating’ discharge device will be recommended. Aspirating devices produce a more viscous foam that is highly effective for minimising burn back and keeping the foam contained. They are discharged through foam-making devices such as branchpipes, top pourers, foam cannons, foam sprinklers or high-expansion generators.
Non-aspirating devices are best used when there is a need to spread the foam over a large area. They are typically discharged through water nozzles, sprinklers or deluge nozzles.
Weighing up the appropriate foam for a site
Fire-suppression foams are an extinguishing agent that cool and separate the ignition source of a fire. They are designed to smother the fire and any associated vapours, while they can also prevent ignition.
There is a science to choosing the right foam for the right site. The key is to know and understand the risk product you are trying to protect and conduct performance testing to ensure that the foams are suitable with system designs for fixed and portable firefighting equipment.
Firefighting foams fit into two broad categories – aqueous film-forming foams (AFFFs) and protein foams which contain fluorinated surfactants; and fluorine-free foams. They are subject to strict management and containment rules because of the risk of toxin compounds such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) entering waterways.
AFFFs were originally developed in the 1920s and 1930s and have evolved over many years. They should only be used on hydrocarbon-based fuels because the film applied to the surface will not keep the alcohol-based fuels from mixing with water in the foam. When this occurs, it destroys the foam. For alcohol-based fuels, an alcohol-resistant aqueous film forming foam (AR AFFF) should be used.
Some of the newer synthetic foams are increasingly in favour because they are a fluorine-free product, which means that they are more environmentally friendly and safer. In short, they can protect sites from fires without contaminating the surrounding land and waterways.
While they are suitable for scenarios such as wildfires, aviation and marine events, the fluorine-free foams have historically not been suitable for use in portable fire extinguishers or non-aspirated spray that is used to protect large machines. However, in recent times as these foams have continued to be developed and tested, it is now starting to be accepted that these foams can be used and seen as a suitable alternative to the historically more common types.
Insist on experience when commissioning foam-dosing solutions
Given the complexity of the discharge services and the foams, it is essential to engage experienced firefighting specialists when deploying foam fire-suppression systems. Doing so will ensure that at-risk sites have the right foams that meet industry standards and which perform properly when needed most.
There is no room for cutting corners when rolling out and maintaining such complex fire-suppression systems. Opting for an inappropriate discharge service and foam could result in catastrophic fires that jeopardise the safety of employees and the site itself.
Major facilities should deal with fire-suppression experts when it comes to installing foam dosing systems. So, find out more and contact Australia’s leading provider of foam suppression solutions.
Also read : Ensuring fire safety in commercial kitchens – the importance of fire-suppression systems