Class A Foam Delivery System Considerations

By Shawn Oke

If you stroll the show floor of FDIC International and check the pump panel of each apparatus, you will notice a common thread: Most have onboard foam concentrate delivery systems.

These systems appear to have become the norm rather than the exception. If your department is considering placing a foam concentrate delivery system on your next apparatus, there are several considerations before you design your apparatus.

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First you must determine the type of foam concentrate delivery system you will place on your apparatus. There are three common types of systems being placed on most apparatus: in-line eduction, compressed air foam, and injection. While examining apparatus on the show floor at FDIC International 2019, it was obvious to me that injection was the most common system being placed on apparatus. I am a huge fan of these systems for several reasons, some of which I discuss below.


The injection system provides you with a system that is accurate at various percentages. This accuracy allows the operators to ensure they are delivering the proper percentage of concentrate to the hoselines. This accuracy also ensures foam concentrate isn’t being wasted by being delivered at a percentage higher than what is needed. Injection delivery systems can deliver concentrate at a wide range of percentages; many systems can deliver concentrate from 0.10% to 6%. This wide range allows most injection systems to deliver any concentrate available to the fire service at its proper percentage. The accuracy and wide percentage range allow the department to change concentrates during the life of the apparatus should a more effective foam concentrate become available at a different concentrate percentage than what is currently in use.

Invest in the safety of your personnel by having an onboard foam fill system installed when designing your apparatus.

1 Invest in the safety of your personnel by having an onboard foam fill system installed when designing your apparatus. This system will reduce the chances of an injury, especially during incidents requiring large amounts of foam concentrate. (Photos by author.)

Designing your apparatus with easy access to your foam delivery system will pay dividends when you need to perform maintenance on your system.

2 Designing your apparatus with easy access to your foam delivery system will pay dividends when you need to perform maintenance on your system.

Injection delivery systems are generally simple to use and require little effort by the operator. My experience with the fire service has been if it is too complicated it probably won’t be used. When determining the type of concentrate delivery system, consider how easy the system will be to use at 2:00 a.m. when the apparatus arrives on the scene of a major fire requiring multiple attack lines. If the concentrate delivery system requires the apparatus operators to spend a lot of time ensuring incoming pressure is this and discharge flows are that, my experience tells me they are not going to use the system. The majority of the injection systems available today simply require one button be pushed to turn on the system. The system does all the work so the apparatus operator can focus on other important tasks.


Be sure the delivery system you place on your apparatus will deliver the foam concentrate your department uses. All concentrate delivery systems aren’t created equal, so it is vital you ensure the delivery system being installed on your apparatus will deliver the concentrate you are planning to use.

The thickness, or viscosity, of foam concentrates is measured in centipoise. It is important to know the centipoise of your concentrate at room temperature and at the temperatures at which your concentrate delivery system is going to be expected to deliver the concentrate. The centipoise of a concentrate increases as the temperature of the concentrate decreases. If you live in an area that is subject to cold temperatures for long periods, it is very important that you determine the centipoise of your concentrate at these low temperatures. Many concentrate delivery systems available are not designed to pump high-viscosity concentrates. If you don’t do your research, you might end up with a concentrate delivery system that won’t work at all with the concentrate you are using.

Ensure the concentrate delivery system is accessible with relative ease. When I look at the concentrate delivery system on an apparatus, I look at how accessible the pump and other components of the delivery system are. If you place an injection system on your apparatus, you will need easy access to the concentrate pump to clean the filter, which should be done on a regular basis. You may also need to access the pump to calibrate the system and make repairs. If you take the time while designing your apparatus to provide easy access to the concentrate pump, it will pay dividends throughout the life of the apparatus.

Ensure the valve between the delivery system and foam concentrate tank is very easy to access. If something happens to your concentrate delivery system, such as a broken line or the need to make major repairs, you will need to shut off the flow of concentrate from the foam concentrate tank to the delivery system. In the case of a broken line, being able to shut off the flow quickly could mean the difference between saving your concentrate and having a big and expensive mess to clean up. When designing your apparatus, be sure the shutoff valve from the tank to the delivery system is in a place that you can access quickly and with very little effort.

When plumbing the discharges on your apparatus, make sure you put foam concentrate on every available discharge. When we designed our first apparatus with a foam concentrate delivery system, we didn’t have any experience with onboard delivery systems. The salesperson helping us design the apparatus told us we should only put foam on three lines so if we wanted to flow water and foam at the same time we would be able to do that. As time passed and our reliance on using foam for fire suppression became the norm rather than the exception, our decision backed us into a corner when deciding which hoseline to pull at an incident. Our lack of planning for the future now limits us to one 1¾-inch preconnect attack line with foam. We learned our lesson with this apparatus, and on our next two apparatus we designed every discharge possible, including the deck gun, to deliver foam. Our decision to provide foam on every possible discharge has allowed the company officer the ability to deliver foam regardless of the attack line used.

When you provide every discharge on the apparatus with the ability to deliver foam, ensure your delivery system is large enough to support large flows at the concentrate delivery percentage required by the concentrate manufacturer. A concentrate with a higher delivery percentage is going to require more concentrate and will reduce your ability to deliver large volumes of finished foam. There are many concentrates available to the fire service that provide excellent extinguishing properties at very low concentrate percentages. These low concentrate percentages allow the foam concentrate delivery system to deliver in excess of 1,000 gallons per minute (gpm) of finished foam. The low concentrate percentages also allow the concentrate being carried by the apparatus to generate large amounts of finished foam.

Consider placing the largest foam concentrate tank possible on your apparatus. When designing an apparatus, we often fail to plan for the rare incidents the apparatus might respond to. This is generally the case when it comes to how much foam concentrate the apparatus will carry in its onboard tank. When the rare incident occurs and you need a large amount of foam concentrate, you will be glad you have it on your apparatus. When determining how large of a concentrate tank to place on your apparatus, consider the hazards you are protecting and possible gpm flows these hazards may require in a worst-case scenario. Also consider how long it will take to have concentrate reserves brought to the scene to refill your concentrate tank. You can have too much concentrate on your apparatus and not have any problems, but if you don’t have enough you can surely get in trouble.

If you are putting a concentrate delivery system on your apparatus so you can deliver foam on a regular basis, consider adding a foam concentrate fill system. My experience has been that a concentrate fill system is often seen as a luxury and is generally removed from the apparatus when cost-saving measures are required. If you are going to use your concentrate delivery system as it should be used, then putting a fill system on your apparatus is a must. If you fail to install a concentrate fill system on your apparatus, you are creating a much better chance of a costly injury to a department member. If you don’t have a concentrate fill system, personnel must climb to the top of the apparatus and have someone lift a bucket weighing in excess of 40 pounds above his head to hand it off to the person on top of the apparatus. This exposes personnel to possible back injuries from lifting and other injuries from climbing up and down the apparatus. The cost of one injury would more than pay for the cost of the concentrate fill system.

As you can see, there are numerous considerations when deciding to place a foam concentrate delivery system on your apparatus. These items are not all-inclusive, so spend time doing your research on your foam delivery system prior to signing the contract on your next apparatus. Reach out to departments that have concentrate delivery systems in service and learn from them. I assure you they have positive and negative lessons they have learned that will save you time and money in your next apparatus.

Shawn Oke retired in 2019 after a 30-year career, nine of them as chief, with the Albemarle (NC) Fire Department. He has a bachelor’s degree in fire engineering technology from the University of North Carolina Charlotte. He is a graduate of the National Fire Academy Executive Fire Officer Program. He is the co-founder of the Kill the Flashover project where he has been involved in extensive wetting agent research.

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