Husky Foam System: Checking fluids, filters important

Foam can be a powerful weapon fighting a fire. Whether Class A, Class B or emulsifier – and their very different applications – the Husky Foam System provides important suppression capabilities.

  • Class A foam is the most common type used by agencies to combat Class A fires. It attracts carbon by being absorbed into solid combustible materials and surfaces. In doing so, it reduces the surface tension of water, allowing it to penetrate more deeply into whatever is burning. As an added benefit, foam helps prevent rekindling of fires once put out.
  • Class B foam is used in cases of flammable spills such as a tanker truck or perhaps at a refinery. The biggest difference between the foam types is that Class B foam repels carbon. It’s like throwing a blanket over flames when escaping vapors or the spread of the fire is an issue.

Some fire agencies prefer emulsifier foam, which combines the characteristics of Class A and Class B. One caution for those departments that use it: Emulsifier foam needs to be flushed with plain water from the system after each use. Not flushing risks corrosion of the O-rings and seals. 

Flushing takes about 30 minutes and should be done at the fire scene.


Many apparatus made by Pierce Manufacturing have the ability to apply all foam systems. Regardless of which is used most often, there are some simple maintenance recommendations that operators should be aware of. Golden State Fire Apparatus, in tandem with our partners, strongly urges our customers to follow a regular preventive maintenance schedule for all their equipment.

Hydraulic Fluids and Filters

Weather and temperatures play in a role in selecting the right hydraulic fluid. The fluid used for cold weather foam application may not function properly at higher temperatures. Fluids should be regularly checked and changed, depending on the circumstances and season.


The hydraulic oil in the Husky System is filtered through a 10-micron cleanable filter located in the hydraulic block. Though this filter can be cleaned up to 10 times before it needs to be replaced, Husky strongly recommends that it be changed out when the fluid is to maximize performance and keep out dirt that can cause excessive wear in the system.


Whether cleaning or replacing the hydraulic filter, solvent cleaner and a rag should be used to wipe the area around the filter before it is removed.

Use solvent cleaner to clean the filter. Blow it dry with compressed air before putting it back in place. Do not clean the filter with a rag or anything that might leave any type of particles on it.

In each case, the baskets are easy to clean. Remove the lug nuts, check the strainers with water and then reinstall. Replace any baskets or strainers that have obvious damage.

More information about the Husky Foam System and its maintenance can be found at:

Debris can cause damage to your fire suppression system and prevent it from operating properly. Golden State Fire Apparatus carries an extensive inventory of parts for your emergency vehicle. We know exactly what your apparatus needs to keep it in tip-top shape.

Our expert staff of Emergency Vehicle Technicians works out of our 35,000-square-foot maintenance facility in Sacramento. We continually invest in tools and equipment so that your emergency vehicle receives the utmost care, while reducing the man-hours required to get the job done right.


If you have any questions about any aspect of your equipment’s performance, we’re here to help. You can reach us at (916) 330-1638 or at