Fire Extinguishers: A Good Bunch, But Get More than the Minimum
They all performed comparably, but we'd pick the Kidde 1044, which was somewhat effective on Class-A fires and discharged for three seconds longer than the others.
Back in the days of wooden ships with pine-tar sealants, fire was the threat most feared by mariners. Nowadays, with plastic hulls, engines, fuel tanks and extensive use of electrical devices, neither the threat nor the fear has gone away. A fire at sea is still an extremely serious hazard, and a major cause of property damage and death. Out on the water, you can’t simply call your local fire department—if there’s a fire, you have to deal with it.
The U.S. Coast Guard has wisely included fire extinguishers among their legal requirements for boaters. Unfortunately, USCG requirements are for minimal, not optimal protection. And identification codes on fire extinguishers can be extremely confusing. We’ll try to help you pick your way through the labyrinth of letters, size designations and extinguisher types available.
Fire extinguishers are classified by the type of fire they can handle and (more roughly) by how big a fire that can be. Class A fires involve ordinary solid combustibles: wood, plastics, rubber and textiles. Class B fires occur with combustible liquids: oils, fuel and greases. Class C fires include electrically live appliances or connectors. On a boat, the most serious concern is Class B; all Coast Guard-approved extinguishers can deal with a Class B fire, although most can also deal with Class C; most also have a Class A rating as well.
USCG labeling doesn’t tell you how well an extinguisher can deal with different classes of fire. Luckily, extinguishers carry, in addition to a USCG designation, a UL code that provides at least comparative performance information for the three different classes of fire. A UL label might display a rating of 1A;10B:C or 5B:C—the former would be capable of dealing with a small Class A fire, and somewhat larger Class B and Class C fires. The latter would not be rated for Class A, and would have half the capacity of the former in dealing with Class B and Class C fires. Both extinguishers would be rated as B-I (or BC-I) by the Coast Guard, whose ratings are based solely upon the weight of fire-fighting chemicals discharged by the extinguisher. A B-I carries at least two pounds; a B-II carries over 10.
How They Work
There are a number of different types of fire extinguishers, each with its strong and weak points. Some are simply not suited to marine application. Among the extinguisher types that are suitable for boats, there are:
• Dry Chemical Extinguishers. These are the most popular marine type. They're inexpensive and have low toxicity—an important characteristic if you have to use one in an enclosed cabin or engine room. They’re not particularly effective on Class A fires but work well on Class B and Class C conflagrations. Most dry chemical extinguishers use either ammonium phosphate or sodium bicarbonate as their active agent. Of the two, ammonium phosphate works a bit better on solid-fuel Class A fires; sodium bicarbonate makes for an easier clean up. Any dry chemical extinguisher leaves a mess after you use it.
• Halon variants. Halon, strictly from the point of view of putting out a fire, makes for an almost ideal fire extinguisher. A chlorofluorocarbon, it was effective in smothering all classes of fire, left no residue and was essentially non-toxic. The use of Halon was discontinued several years ago because of its adverse effects on the environment, particularly its role in destroying the earth’s ozone layer.
• Aqueous Foam. This is a relatively new technology for handheld fire extinguishers. Aqueous foam, which coats and clings to both horizontal and vertical surfaces, smothers the fire. It works well on all classes of fire, not spreading Class B fires as does a pressurized plain-water extinguisher. Aqueous foam is apparently a poor enough conductor of electricity to be suitable for use on Class C electrical fires and is extremely effective on Class A fires as well. Clean-up is easy; toxicity appears to be low but is still under study. One caution, though: While you can use an aqueous foam extinguisher on a flaming frying pan, it should not be used when dealing with a large quantity of burning grease or cooking oil or alcohol fires when more than a quart or so of alcohol is involved.
There are a couple of types that you may encounter that are poorly suited for marine use:
• Carbon Dioxide (CO2) extinguishers. While these work well for Class B and C fires and require no clean-up, the C02 gas dissipates easily, making these extinguishers effective only in enclosed spaces. They don’t cool the fire, so they leave a potential for spontaneous re-ignition.
• Water (or soda-acid). While water extinguishers are very good for dealing with Class A fires, they tend to spread burning liquids, making them unsuitable for dealing with a Class B fire. Water conducts electricity, which makes this type hazardous for dealing with electrical fires. Water extinguishers are large, heavy and difficult to store.
What We Tested
Our original idea was to canvass the local marinas, chandleries and hardware stores and pore through the mail-order catalogs in search of as many brands of B-I extinguishers we could find, as this size is the one required for most boats in the size range owned by our readers.
We quickly discovered that, in our area at least, Kidde was the only brand available, and that all of the USCG-approved models were dry-chemical types. Xintex-Fireboy, a manufacturer we’ve encountered in the past, informed us that the only portable extinguishers they make are of the Halon-variant type; we felt that these were too expensive to include in this project.
We did find some Coast Guard- listed dry chemical extinguishers from First Alert, and so we included them in our tests. When we found more than one size extinguisher that carried the USCG rating of B-I, we bought them all. We also found one aqueous-foam extinguisher—the Kidde Fire Out Foam—which we bought for comparison purposes, although it doesn’t carry a Coast Guard label.
How We Tested
Our first step was our usual one: We studied the labels and instructions. We looked for legible, clear instructions displayed prominently on the extinguisher itself. Then we measured and weighed each extinguisher, determined how well each mounting bracket functioned (the Coast Guard standard will not accept a simple hanger-type bracket), how obvious each was to operate—a fire at sea is not particularly conducive to analytic thought—and how easy each was to handle and aim. We checked each unit for ease of checking the pressure indicator.
Then we used each to put out a fire. We floated some kerosene on a tub partially filled with water, added some wooden sticks and lit the whole mess. We weren’t interested in trying to measure each extinguisher’s fire-fighting capability—UL tests are universally recognized and any attempt on our part to do our own testing would be mere repetition. We were interested in finding out the human aspects of using an extinguisher: how easy it was to control each extinguisher’s discharge, how simple it was to avoid splattering of the burning materials and for how many seconds each extinguisher would operate.
What We Found
Our most dramatic finding was the limited window of opportunity that each of the dry chemical extinguishers provided to put out a fire. The Kidde UN 1044 sprayed its dust for13-1/2 seconds; all the others pooped out in 10 to 10-1/2 seconds. Each one managed to extinguish our small fire without a problem, but we’d hate to be at sea facing a fire that wouldn’t go out in that short a period. Interestingly, we noted little or no difference in time between a 5-B:C and a 10-B:C extinguisher. Apparently the greater-capacity units simply deliver more dry chemical over the same period of time.
Another factor that struck us is the dramatic loss of visibility that occurs when you use one of these extinguishers. Our fire became completely obscured by the thick cloud of dust from the extinguishers, and aiming became more a factor of memory than of visibility. The third aspect of using one of these dry-chemical extinguishers is the thick covering of white powder left behind after the fire is out.
The Kidde UN 1044’s powder, we found, melted on hot surfaces, making complete clean-up almost impossible; the other three extinguishers used non-melting sodium bicarbonate, which makes clean-up possible, but still extremely difficult and tedious.
The First Alert Products had very comfortable ergonomic trigger mechanisms, but the Kidde ones weren’t bad. After all, comfort isn’t a serious requirement for a device that you’re only going to be holding for 10-13 seconds. Operation of all units was straightforward. You remove the extinguisher from its bracket, pull out or break off a safety tab (red) and squeeze the handles or pull the trigger. Aiming was easy, and all the units were similar in weight, size and balance.
The two First Alert models and the Kidde Mariner 10 come with plastic brackets; the Kidde UN 1044 has a steel bracket. We really have a slight preference for metal brackets. The plastic brackets won’t rust or corrode; the steel bracket will but is probably a good deal stronger initially.
All four models tested have commendably easy-to-read instructions on the extinguisher itself. While using an extinguisher isn’t difficult, it’s a good idea to have all crew members review the instructions in a non-emergency setting. It’s not something you want to be reading for the first time by firelight.
All have gauges that are easy to read. Since gauges can fail, you should test your extinguisher. Weighing the device is an effective alternative to firing its contents. All four models list maximum and minimum weights for fully charged units. Both samples of the Kidde UN 1044 weighed in at slightly under the permissible minimum weight when we received them, although the gauge indicated that they were fully charged.
These requirements, like all USCG requirements, represent the minimum you must carry. Considering the seriousness of a fire, and the lack of fire-fighting facilities out on the water, limiting yourself to the minimum number and size of fire extinguishers makes no sense.
You should never have to walk as far as half the boat’s length to reach an extinguisher. Extinguishers should never be mounted so that the probable source of fire is between you and the extinguisher. In enclosed spaces, the ideal location of a portable extinguisher is next to the exit door. The galley should have an extinguisher, and there should be one in each sleeping area and in a cockpit locker.
Regardless of what you may have been told, size matters. A higher-capacity extinguisher is better than a smaller one; two are better than one. Fire extinguishers should be checked monthly. Make sure that they’re fully charged, that safety seals are intact, and that brackets are sound.
We can’t make any firm recommendation as to which extinguisher you should get—all performed comparably. If pushed into a corner, we’d pick the Kidde UN 1044 over the other three: it’s the only one that’s even somewhat effective on Class-A fires, it delivers for three seconds longer than any of the others and it has a metal bracket rather than a plastic one. On the downside, you have to check the bracket for corrosion and rust, and the UN 1044 made clean-up extremely difficult. If you’re going for low cost, the First Alert Marine 10 is your choice: It lists for only one buck more than the lowest-priced (and smallest capacity) First Alert Marine 5.
The best way of fighting a fire is still by making sure you don’t have one. Everyone on board should be aware of safe refueling and venting procedures. Everyone should be cautioned in the use of open flame, sparks, and the disposal of hot matches andflammable materials. Fire extinguishers should be pointed out to anyone new coming aboard.
Finally, exercise common sense in the galley—no towels or curtains over the stove, and be extra careful cooking underway.