Up in Smoke: fixed fire suppression systems
Other than “Man overboard!” hearing “Fire!” may be the most frightening sound aboard a vessel, especially one that is away from the dock. That’s why fire suppression systems should be on your spring commissioning list when you head back to the boatyard this year, probably even ahead of things like bottom paint and electronics upgrades.
Approximately 90 percent of onboard fires start in the engine room. More than half are caused by electrical wiring issues. A fixed fire suppression system that triggers automatically is your best bet to fight a blaze early when there’s still a good chance of keeping it contained.
Fireboy-Xintex, Sea-Fire, and Kidde are well-known makers of automatic fire suppression equipment for recreational boating and although some are DIY, more complex iterations are best left to boatyards that are savvy in the installation and servicing of these products. Here are five things to discuss with your project manager about pre- or custom-engineered fire suppression systems.
1. Determine the space and measure the area you are trying to protect.
Size your system appropriately by measuring total cubic feet. For example, Fireboy systems are available to protect engine rooms and machinery spaces from 25 cubic feet to 17,300 cubic feet. “Pre-engineered systems are available for up to 4,000 cubic feet and should be installed exactly per the manual instructions,” says Keith Larson, vice president of sales and marketing for Fireboy-Xintex. Many extinguisher systems are designed to automatically discharge in 10 seconds whenever the space ambient temperature reaches 175 degrees Fahrenheit, but it’s important to install a manual override, as well.
2. Decide on the suppression agent.
There are three classes of fire:
- wood, paper, textiles, etc.,
- flammable liquids and gases, such as gasoline, propane, and oil,
- energized electrical equipment, such as motors and appliances.
For the engine room, It’s best to choose an extinguishing agent that is effective for surface fires of all three types.
Traditional fire extinguishing agents, such as water and dry vs, can cause damage to equipment, and a CO2 discharge, while a person is in the engine room, could
be fatal. Halon was formerly the extinguishing agent of choice, but due to its ozone-depleting properties, it has fallen out of favor. A highly effective, green and safe agent
is 3M’s Novec 1230. Its low toxicity is safe for the crew. It vaporizes rapidly and is non-conductive and non-corrosive. Delicate electronics won’t be harmed, and no residue will be left behind.
3. Determine the best location for installation.
Most agent storage tanks can be mounted horizontally or vertically, which is good because space comes at a premium in most engine rooms and also inside the protected space and/or remotely through fixed piping and nozzles.
Wiring is necessary for both automatic and manual (cable) activation
and is usually the most time-consuming part of the job, so a large portion of your yard bill will be in labor. Don’t install the units near intake vents where drawn-in air can fuel the fire or cool the system’s temperature-sensitive trigger, potentially causing a delay in discharge. Make sure the system is readily accessible and includes ongoing maintenance, including periodic inspections and testing.
4. Determine necessary peripherals and legal issues.
If the system discharges under way, shut down the engine, generator and bilge blower to stop the motors from sucking in additional oxygen. Larson points out that the U.S.C.G. requires an engine shutdown module and a system status display at the helm. Also, install the manufacturer-supplied bracket to meet U.S.C.G. standards, and don’t forget about required carbon monoxide and smoke detectors.
“For a 50-foot boat, expect a cost of $2,500-3,000,” says Larson. That will depend on the access to the engine room and the complexity of the system. But when you put the cost up against the loss of your boat, or worse, it becomes a small price to pay for peace of mind.
If you’ve ever seen the result of an onboard fire, it’s a terrifying sight. It’s also the strongest argument for a visit to the boatyard this spring. Put a thorough inspection of an
existing fire suppression system or the installation of a new one at the top of your list. Don’t let your summer go up in smoke.
By Zuzana Prochazka, Southern Boating March 2018
Photo: © Shutterstock by Nixx Photography