Liberty Frac Pumps with AFEX Fire Suppression Systems for the Digital Oilfield

As published in the magazine: The American Oil & Gas Reporter

From North Dakota to Ohio to Louisiana and Texas, wherever hydraulic fracturing is being done there have been fire incidents over the years which have resulted in total surface equipment loss. The bottom line cost of such “thermal events” is generally in the tens of millions, which is to say nothing of productivity losses and any associated public relations damage done to the affected stakeholders. All things considered, adding fire suppression systems to at-risk machinery is a safe and cost effective solution to this potentially devastating problem.

A vehicle fire suppression system is a safety accessory that is mounted on a piece of machinery, such as a pump or blender, to protect it in the event of a fire. Comprised of tanks filled with fire-fighting agent, fire-detecting sensors, and a distribution network of tubes, hoses and nozzles, it is permanently affixed to the machine. In the oil & gas industry, these systems are appropriate for use on the vehicles used in hydraulic fracturing and on any diesel generators used on site.

Fire Suppression for Safer Job Sites

A fire suppression system stands ready to discharge whenever needed, its nozzles aimed at the most at-risk parts of the machine. Commonly protected areas of a vehicle include turbochargers, starters, fuel filters, batteries, alternators, and transmissions. Sensors, which are activated once operating temperatures exceed predetermined maximums, are placed around these key areas to guard them. The nonstop protection this provides is beneficial since it is right at the point where fire is likely to start, which means operators don’t have to approach a fire should one erupt. This is especially important on a well pad being fracked since the pumps are parked so close to one another and minimal physical access is a complicating safety issue. Ultimately, fire suppression systems make for a safer job site as a result.

A system discharge is the result of either sensors sending an alarm mode to the control panel, which then automatically releases nitrogen to push the agent through the distribution tubing and out of the nozzles onto the protected areas, or as the result of a manual, physical release of the nitrogen which starts that same process. The agent will then knock down the flames and keep the fire from becoming established.

Control Unit installed on heavy duty equipment for Fire Protection
Control Unit for system monitoring and fire detection

It is critical that a system with an appropriate amount of ruggedness is used in any given circumstance so that it stands up to the demands of the working environment and so that it is ready whenever it is needed. A system geared towards use on-road on a passenger bus, for example, would be much smaller and less robust than one tough enough for the physically abusive environment that is typical of a well that is being hydraulically fractured.

Where Are Suppression Systems Used?

The use of fire suppression systems to protect heavy equipment is a well-established standard within a number of industries, including mining, wood processing, and waste management. The main reasons for their use is the protection of personnel and vehicles, but the work environment itself is also indirectly protected through the use of these systems, whether it be an underground coal mine, a forest or a landfill. By extension, fire suppression systems are productivity tools which save money, as reduced downtime equates with more hours worked and more profits generated.

These industries have chosen to utilize onboard fire suppression systems because, on balance, the investment made in them is justified versus the risk of going without. There is no reason why the same could not be said of the hydraulic fracturing industry. It is worth noting that in certain other instances use of fire suppression systems is required by insurance companies in order to receive a policy since it helps them to mitigate the risk of having to pay out for total losses.

Due to the fact that frac pumps are so close to each other when working at a well pad, the risk of one machine catching fire and spreading to the surrounding machines as a result is real. Considering that the most common cause of vehicle fires is a ruptured hydraulic line spraying fluid onto hot engine surfaces, the constant vibrations of the equipment used in fracking makes for an especially risky environment. The point being that the investment made in just one saved machine can ultimately pay for fleets’ worth of protection many times over, especially when compared with the replacement cost of multiple machines.

How to Choose the Right Fire Suppression System

Anyone familiar with a frac site knows that the vehicles are working as hard and as long as any equipment in heavy industry. With all the twisting, flexing and vibrations of the machine chassis, there is no question that a fire suppression system needs to be as rugged as possible to stand up to the rigors. When deciding on a fire suppression system, durability and reliability are always important factors to consider. There are a number of key characteristics which account for these, including: agent tank variety; tubing/hosing; electronics; and the agent itself.

Agent Tank Variety

Agent tanks can be one of two types: stored-pressure or side cartridge. In a stored-pressure variety the nitrogen that would power the agent through the distribution network is contained in the same tank as the agent itself. This design of tank is more likely to leak and lose pressure over time. Considering the constant vibration of a hydraulic fracturing vehicle this type is an impractical choice versus the side cartridge variety, which holds the nitrogen in a separate, leak-proof container. This is why side cartridge operated systems are the standard in mining.

Tubing and Hosing

Tubing made of stainless steel makes for a very rugged distribution network. Some amount of rubber hose will invariably be used in a system, but the less of it there is, the less there will be to replace over time due to regular wear and tear. Not only is the stainless steel tubing more resistant to the chemicals which might come into contact with the system, it will not dry rot like hose, meaning it likely won’t ever need to be replaced. This reduces maintenance costs over time.

Fire Suppression System Stainless Steel Tubing
Stainless Steel Tubing Distribution for Reduced Maintenance Costs


A control panel is the central electronic brain of the system. These components monitor the detection network and activate the system when an alarm goes off. The more technically advanced ones provide a log which can be used for tracking system activity. Remote actuation may be incorporated as well so that control vehicle personnel can activate the system from a distance. It is telematics compatible and can be used to power horn strobes to alert operators to a system discharge, a suitable accessory for a loud environment.

Chemical Agent

As for the agent itself, there are two kinds: a dry chemical A:B:C powder and an A:B liquid. The dry chemical used in a vehicle suppression system is proven by decades of application in the heavy industries. Very similar to the material found in handheld portable extinguishers, it works very quickly at knocking down and suppressing a fire. It is suitable for use on debris fires (Class A), fuel fires (Class B), and electrical fires (Class C). The liquid agent comes out of the nozzles and foams to an extent, creating a film coating across the surfaces it is sprayed on. It also provides a cooling effect to lower surface temperatures in addition to suppressing the flames themselves.

These agent types can be used independently of one another, but when protecting a frac pump, a dual agent system is best because it takes advantage of the benefits of each. This makes for a more efficient system than either type alone can create since it will work quickly and guard against a reflash fire that is the result of hot surfaces causing a reignition.

Operational Options to Consider

Besides its physical properties, there are a number of operational options to be considered when evaluating the configuration of a fire suppression system. One of the most basic distinctions is the difference between an automatic system, which has a network of sensors that actuate the system when tripped by excessive temperatures, and a manual-only system, which depends on a physical input from an individual for actuation. The difference between the two does not impact the amount of fire-fighting agent that would be utilized by the system, but it can significantly impact the time between a fire breaking out and when the system actuates.

Responding to a fire as quickly as possible is preferable in all cases, so the manufacturer’s recommendation typically will be that an automatic system be utilized. Considering a fracking spread is congested, with numerous machines obscuring the on-site personnel’s ability to observe a fire early on, a detection network would be highly advisable.

Another system feature which is prudent to take advantage of is engine shutdown. When a fire breaks out on a vehicle, it most often involves the spraying of a fluid onto a hot surface. Should the engine continue to run, the hydraulic line which has been damaged will remain pressurized, causing it to continually pump fuel onto the fire. Any cooling fans might also contribute to a fire’s growth, so shutting them down is also important. Having the fire suppression system shut off the engine is a critical way it can help keep a small fire small, which is why the feature is taken advantage of more often than not.

Hydraulic fracturing equipment operates in an extremely abusive environment where vehicle fires are quite literally an accident waiting to happen. Waiting until a fire breaks out to contend with it with portable fire extinguishers alone is to gamble that the fire won’t become fully involved and spread before it can be fought. With so much at stake from safety and financial perspectives, this is clearly not a chance worth taking. Rugged, heavy-duty fire suppression systems go a long way towards accounting for the threat of vehicle fires at well pads by being the first line of defense, and the companies that utilize them will be safer than ever before as a result.

Click here to watch a video on fire suppression systems in the oil and gas industry.