How Do Marine Fire Suppression Systems Work?

A Guide for Beginners

Congratulations! You’ve bought or are captaining a boat large enough to merit a marine fire suppression system. Excellent…except, what’s that? A marine fire suppression system. Yes, also called a fixed fire system, a boat fire suppression system, a yacht fire suppression system, or a vessel fire suppression system.

Oh, you’re unfamiliar. Except for a few surly sailors, marine engineers, and experienced fire suppression technicians, you are in the majority. Almost no one is aware of how these costly and incredibly important systems operate. Read on to see how marine fire suppression systems prevent damage to property and lives.

Marine fire suppression systems are designed to put out large fires in dangerous areas that would not be suppressed by most fire extinguishers. In fact, most are in the engine room or compartments. If a fire ignited, opening the compartment would add fuel (oxygen) to the fire and make matters worse. You’ll need your suppression system in top shape to perform if the worst occurs. Let’s look at the parts.

Cylinders: It all starts with a cylinder, or bottle, that holds the fire suppressing agent. They look much like fire extinguishers but generally hold a different substance than your everyday ABC fire extinguisher.

Cylinders are mounted using a special bracket to ensure safety and to prevent accidental discharge or damage.

Clean Agents: These are the gases or liquids used to suppress the fire. Marine fire suppression manufacturers use precise charts to help boat owners and fire suppression technicians calculate the amount of extinguishing agents needed. When the agent is released, it depletes the oxygen or smothers the oxygen temporarily to extinguish the flame.

Heat Sensors: Each cylinder is equipped with one or more heat sensors. These are strategically located and are usually composed of a tiny glass bulb or small fuse. When the engine compartment (or other such equipped room) reaches a temperature of 175ﹾ Fahrenheit the bulb or fuse switches on. This relays to the cylinder to release the extinguishing agent.

Nozzles: These pieces dispense the clean agent from the cylinder to extinguish the fire. Each cylinder has at least one nozzle. The entire clean agent should be dispensed in about 10 seconds.

Tubing/Piping: Not all models come equipped with tubing or piping. However, in a larger engine room, you will see this more often. It allows the sensors and nozzles to be located where they will be most effective. Yet, they are still connected to the cylinder. These parts and cables also allow the systems to be connected to helms displays and accessories to turn off the engine.

System Installation

Some marine fire suppression system manufacturers suggest that you can install simple systems yourself. They’re not wrong, but unless you are very mechanical it’s best to leave the installation to a trained professional. Most fire suppression system technicians know the specifications and laws regarding your system.

They carry special equipment and can teach you how to use the system as they install and inspect it. You’ll also need the system certified by a permitted fire suppression technician. When you call your local fire equipment dealer, be sure to ask the technician about their experience with marine fire suppression systems.

Most marine fire suppression system manufacturers also offer to install or engineer a system for you. Check the Ansul, Fireboy-Xintex, Kidde-Fenwal, or Sea-Fire websites for further information or manuals.

Operation and Monitoring of Systems

Now that you understand the parts of your system, we can review the operational aspects of the suppression system. As the boat owner or captain, you are responsible for the safe operation of the fire suppression system. There are three different ways a system can operate: manually, automatic/manually, or automatically. You’ll need to know how to activate your system.

First, do NOT activate the system while you or anyone else is in the engine compartment. With no oxygen to breathe, death is a possibility.

Second, locate your accessories. Examine your boat for a manual discharge pull station. This is the location you will activate the system from if for some reason the sensor malfunctions. Next, look for a discharge sensor display, which monitors your vessel 24 hours a day. When you board the boat, check them immediately.

You will know if your system has discharged while you were away. Now search for an early warning temperature alarm. Some yachts have these to avoid trouble. If there is a malfunction in the electrical portion of the engine room or the temperature begins to rise to unsafe levels; you can cut the power and examine the boat before a fire breaks out!

Finally, if you have a diesel engine or have blowers and an exhaust fan- you should have an engine shutoff station. The clean agent and dispensing system cannot smother the fire if all the agent is blown out of the engine compartment. It also helps to keep the fire from getting larger. Remember to ask your fire suppression technician how to reactivate the system in order to turn things back on.

Finally, you will need to monitor these displays while operating your vessel. It’s easy to glance at the displays if they’ve been installed in the helm station. Some yachts even have two. I would suggest checking them every time you board your yacht.

Maintenance/Inspection of Systems

As of 2016, the U.S. Coast Guard (USCG) adopted the National Fire Protection Association’s (NFPA) guidelines for fire protection with fire extinguishers and fixed fire suppression systems. These requirements are more stringent, with a focus on keeping fire protection equipment up-to-date and functional.

So, what does this mean for you? Previously the USCG required that boats with fixed (aka marine) fire suppression systems have them annually inspected and certified operational by local, licensed, fire suppression technicians. The NFPA requires that all fixed fire systems be inspected per the manufacturer’s specifications, every six months.

This seems like a burden, but it is the cost of safety. It is also a smart move to protect your yacht financially. If a fire occurs and damages your boat, the insurance company will want documentation that you have had your fire suppression system certified in the last six months by a licensed company.

Now you know the basics of your yacht fire suppression system. If you want to take further steps, read your fire suppression system manual. Then, be sure to share this knowledge with your passengers, in the hopes you’ll never need to use it. Bon voyage!