Firefighting gearAug 28, 2012
Equipment for voyagers to battle a blaze on board
Fixed fire extinguishers will fight a fire automatically when subject to 175°F. Proper installation, however, is critical. The units should be mounted as high as possible, to ensure the earliest possible discharge, and away from sources of ventilation.
Anxious to see the beautiful coral reef, they piled their diving gear into the dinghy and headed off for an afternoon of underwater fun. After an hour it was time for a break and a change of tanks, so they swam back to their anchored inflatable and pulled themselves out of the water. A billowing cloud of black smoke coming from the anchorage caught their attention. Quickly realizing it must be a boat fire they fired up the outboard and blasted back to see if they could help, only to experience the gut-wrenching realization that their own boat, their liveaboard home with all their possessions, was just about to sink beneath the water’s surface. Their first thought was for their dog, left behind to guard the boat. Luckily, someone found their pet paddling around the harbor, but virtually everything else they owned was either burned up or sunk to the bottom, except for a few forlorn cockpit cushions and some other flotsam gathered up and tossed into the dinghy.
This was a true incident that happened in the ABC islands of the Caribbean to a boat owned by some very experienced voyagers who had spent many years on board. Their boat was equipped with all the latest gear, including a wind generator and solar panels to provide the electrical juice needed to keep all the systems running. They surmised that something went wrong with their wind generator that was spinning away nicely in the stiff Caribbean wind when they went diving. Maybe a wire came loose somewhere, causing a short in a wire that was not adequately fused. Maybe a battery shorted out internally. Maybe the charge regulator failed and the wind generator overcharged the batteries, causing excess gassing, that was then somehow ignited. Nobody will ever know because the boat was thoroughly destroyed and then sunk in deep water.
Automatic fire suppression systems are designed to combat fires before you even know you have a problem, or when your boat is unattended. They can be as simple as pre-engineered extinguishers that are designed to activate when a certain temperature is exceeded — typically 175° to 200° F (79° to 93° C) in marine applications. They can be complicated systems with heat and smoke detectors, remote warning lights and sound signals, engine cut-offs, manual back ups, and emergency shutdowns.
Unlike the typical small portable fire extinguishers that most of us have on board in order to meet U.S. Coast Guard regulations, modern automatic fire-suppression systems utilize a “clean agent,” instead of a fire suppressing powder. The advantages of clean agents are numerous: they are electrically non-conducting (you won’t get shocked by current traveling back up the stream of fire suppressant); there is no corrosive and messy powder everywhere to clean up; there is less likelihood of damaging and/or destroying sensitive electronics or your engine; and lower toxicity. Anyone who has ever discharged a standard, inexpensive handheld fire extinguisher can appreciate how much of a mess the powder makes, and how the choking clouds of powder can make fighting the fire or remaining in the area difficult.
Dry chemical units should be inspected regularly and serviced periodically to ensure they will work. Also, make sure they are well-secured, in a seaway an errant fire extinguisher can become a dangerous projectile.
The great advantages of clean agent fire suppression were realized in the 1960s when companies began making systems utilizing an agent called halon (bromotrifluoromethane). At one time, halon was considered to be so innocuous to humans that companies routinely demonstrated its firefighting effectiveness at boat shows by blasting out small grease fires right in front of admiring crowds of show goers. The fires were quickly put out, leaving behind no visible mess, and the demonstration could begin again just by relighting the grease fire. However, at higher concentrations, above 5 percent, it is considered to be somewhat hazardous to your health, and manufacturers always advise leaving areas where extinguishers have been used.
Even though it is excellent at fire suppression, halon is no longer available for new installations. Halon, it turns out, is an ozone-depleting gas, and its manufacture has been banned since early 1994 under the Clean Air Act.
Existing halon systems can still be inspected and recharged, however, due to a thriving industry of halon recyclers. Apparently, there is no good way to dispose of existing stocks of halon, and the Environmental Protection Agency has allowed the reuse of existing material. According to H3R Clean Agents (www.h3rcleanagents.com) there are no federal or state regulations preventing the continued use of halon, as long as supplies last. The Halon Recycling Corporation (www.halon.org) is a non-profit trade association that can provide more information on the current status of halon.
Older vessels may still have CO2-based firefighting systems, but these have mostly been replaced by today’s clean agent products. One of the great disadvantages of CO2 is that it can also knock out or kill the firefighters when used in an enclosed space, and it doesn’t cool the fire as effectively as the clean agents.
Leading marine fire suppression companies, like Fireboy-Xintex (www.fireboy-xintex.com), Kidde Fire Systems (www.kiddefiresystems.com), or Nautical Fire Suppression (www.nauticalfire.com), continue to produce manual and automatic systems using new clean agents that are considered to be less ozone depleting, like DuPont’s FM-200, which is a heptafluoropropane. These new clean agents work in a similar manner to halon, and have the same advantages, though they require somewhat larger quantities in order to properly suppress fires. The equipment and installation is nearly identical to the older halon systems, and many different products are widely available from marine retailers and distributors worldwide. At this writing, FM-200 appears to be the most commonly used substance in onboard automatic fire-suppression systems.
Kidde states, “The most comprehensive toxicology data of any clean agent available affirms FM-200 is non-toxic when used in compliance with NFPA Standard 2001. FM-200 does not impair breathing or obscure vision in an emergency situation.”
A new innovation making its way onto the scene is the condensed aerosol fire-suppression system, utilizing a potassium-based aerosol instead of a clean agent gas. These aerosol devices release very fine particulates that stay airborne much longer than powders, and leave much less residue than powders. And, like gas systems, the aerosol units flood the fire space with product to extinguish the fire and don’t have to be aimed directly at the flames, as do powder-type or foam extinguishers. Claims are made that the aerosol systems are three to five times more effective than halon systems.
Fireaway, a U.S. manufacturer of aerosol systems, has created Stat-X (www.statx.com). They claim that their systems are more compact, weigh less, have no environmental impact, and are “significantly more effective than alternative extinguishing agents.” At this writing, the Stat-X systems have received approvals from leading marine standards organizations around the world, including Underwriters Laboratories, but apparently they do not yet meet Coast Guard requirements. However, on an uninspected vessel there is no reason that an aerosol system could not be installed, but the boat would also have to be equipped with the proper number of USCG-approved extinguishers.
If there is an approved fixed system installed, the USCG requirement for numbers of portable extinguishers is reduced, but not eliminated. Many marine professionals and safety organizations feel that the USCG requirements should be looked at as a minimum standard.
A fire detection unit, above, and two remote sensors.
Stay in control
The same companies that make fire-suppression systems also make various types of monitoring and control devices. For example, the Fireboy-Xintex FR-1000 can be hooked up to 14 hardwired heat or smoke detectors and it will provide both visual and audible alarms. Fireboy-Xintex has other units available, like the FR-4000 and FR-8000, to monitor up to eight different zones utilizing a two-wire network-type cable.
For fixed systems, the USCG requires warning lights be installed near the helm position in the case of automatic discharge, and American Boat and Yacht Council (ABYC) standards call for both manual and automatic discharge capabilities, along with automatic engine and ventilation shutdown for diesel-powered boats.
The Sea-Fire engine interrupt system by Nautical Fire Suppression will shut down your boat’s engine and engine room ventilation system if it detects a discharge of the automatic fire-suppression system. An automatic shutdown most importantly prevents your diesel engine air intake from sucking the fire suppressant gas out of the engine space, which could lead to a reflame event. It also helps prevent engine damage, may help to cut off fuel and air to an engine-related fire, helps to prevent the removal of the fire suppression agent via the ventilation system, and can help prevent loss of vessel control until the fire is suppressed.
The Kidde Marine SBS System is designed for boats up to 100 feet, and includes DuPont FM-200 discharge cylinders, multiple heat and smoke detectors, control panels, automatic and manual releases, alarms, and engine shutdown options. The network is extendable and configurable for most boats.
Though automated systems are reliable, manufacturers also make remote control panels and cable-actuated releases for manual discharge in the event of a detected fire. These can be useful if a fire is detected prior to the heat rising enough to set off the automatic sensors, or in the case of failure of the automatic sensor and/or the electrical system. They also allow control of the extinguishers from a location outside of the fire space so the crew will not be in danger. Another useful option in control is a manual abort button that cuts off the fire-suppression system in case of inadvertent discharge.
One thing to keep in mind when installing any automatic control system or monitor is how it will interact with other shipboard systems in the case of trouble. For example, many if not most onboard fires are caused by a failure in the electrical system, so naturally many skippers will quickly switch off the main power switches in case of a fire — but obviously, you don’t want this action to shut down your fire control equipment too! Similarly, when you leave the boat unattended you don’t want to accidentally shut off automatic fire systems. One simple solution is to have them run on the same circuit as your automatic bilge pumps. These types of issues are one good reason why the Coast Guard wants you to also have manual handheld extinguishers on board.
Handheld extinguishers that use Halotron 1. This chemical is a “clean agent” and it doesn’t leave chemical residue behind that requires cleanup.
Belt and braces
And, despite the presence of a big, automated system, usually installed in the engine space, it’s a good idea to have a small, inexpensive extinguisher handy in the case of a galley fire. I try to site my extinguishers along the escape routes from areas where fire is likely to occur. For example, in my center-cockpit motorsailor I have an extinguisher in the cockpit (sheltered from the weather under the hard top) near the helm station, but I also have one in the passageway leading to the aft cabin in case someone retreats that direction from a galley fire in the center of the boat. Another one is next to the navigation station, on the opposite side of the boat but near the galley and near the battery compartment. Plus, we always have a garden hose and nozzle hooked up to a faucet in the cockpit — its function is mainly to rinse off after swimming, but it could come in handy for certain types of fires. Redundancy is the watchword in firefighting.
By the way, the old adage to use baking soda to put out galley fires is accurate for very small fires — just be sure not to use baking powder or flour, which might cause a small explosion. It is nice to be able to extinguish the typical small grease fire without polluting the entire boat with fire extinguishing chemicals. For this reason it is handy to keep a dedicated open box of baking soda near the stove but in an area you can reach it if there is a fire. I label the box, “In case of fire.” This is probably the least expensive “fire extinguisher” you can have on board.
It is best to have a multi-level approach to firefighting: small steps for small fires, medium-level equipment (handheld extinguishers) for the next stage, automatic big systems for an engine-room fire or for when the boat is unattended. Be sure to plan how your firefighting equipment integrates with the boat’s electrical and control systems, and how it would work with fire in various parts of the boat. Set it up with redundant controls, both manual and automatic, and then of course have it checked according to the manufacturer’s schedule or at least once per year — warning lights should be checked for proper function more often.
John J. Kettlewell is the author of the Intracoastal Waterway Chartbook, and he has been cruising for more than 30 years. He’s a member of the Taunton Yacht Club and the Cuttyhunk Yacht Club.