Fire extinguishers are a U.S. Coast Guard requirement, and every boating instruction manual starts by telling you how many you need, where to mount them, and how to use them. Unfortunately, the manuals never go beyond that simplistic guidance, even though most fire-prevention authorities agree they are often not the best first response.
Photo courtesy of manufacturer
Such boilerplate guidance overlooks several serious short comings. First, B-1 extinguishers only last about 10-20 seconds. Second, they don’t provide cooling; even if the fire is out, it can reignite from the embers, and if the source is electrical and has not been disconnected, it will almost certainly reignite. Finally, once you have discharged an extinguisher in a confined space you must leave because of the toxic fumes and dust; they actually function by increasing the amount of smoke. You can’t reenter to confirm that fire is out or to mop-up bits that you missed. All you can do is call the Coast Guard and abandon ship, which offshore or in cold water may kill you just as dead.
Perhaps the most generally useful item is a fire blanket. Made of fiberglass or treated wool, they take little space, little training, and do things extinguishers don’t.
What We Tested
We started by fire testing materials you might reasonably have available; cotton towels that can be wet or a US Army surplus blanket. We also tested an old wool fire blanket. We did not test the new blankets for fire resistance; they already tested under NFPA (National Fire Prevention Association) standards.
How We Tested
Our method closely approximated that of NFPA 701: Standard Methods of Fire Tests for Flame Propagation of Textiles and Films. A strip of material is exposed to a flame for 25 seconds, positioned within inches of the flame as per the standard NFPA test rig. When the flame is removed, the material must self-extinguish within 2 seconds and the loss in weight to charring must be less than 40 percent. Another test method is ASTM D 4151: Flammability of Blankets, in which a 3- by 3-inch sample is exposed to a flame for one second and examined for evidence of scorching. ASTM Standard F1889, Cooking Fire Suppression Blankets, references these methods and has additional requirements from seams, attached loops, and packaging.
The real ah-ha moment in this report came when we tried testing some old scraps of fabric, just to get a feel for the test. Cotton jersey went up in flames within seconds. Nylon and polyester took a little longer, but then transformed into dripping fireballs. Finally, we tested a strip cut from an old U.S. army blanket. Nothing. It refused to burn at all for the first 12 seconds. It then gradually blackened and charred, but produced very little flame. When the flame was removed, it self-extinguished in less than two seconds. The Army treats blankets-probably almost everything-because fire is common in combat areas. We also tested an old wool fire blanket, with similar results.
We then tested a dry cotton towel. Within three seconds it was starting to burn and by the end of the test was fully engulfed. It continued burn until there was only a thin lattice of ash. Next we wet and wrung-out the towel and retested. The flame had no effect at all, not even fully drying the fabric. Clearly a soaked towel can be highly effective. However, any cook knows that water can cause a grease fire to nearly explode, so a wet towel should never be used near grease.
Why are fire blankets sold for home and galley use made of fiberglass rather than wool? The reason is not fire suppression effectiveness, but because they fold smaller. In fact, the majority of light duty (single use) fire blankets sold to first responders and laboratories are in fact wool, because it is more effective in wrapping a person to extinguish burning clothing and because it offers better insulation. That said, fiberglass is more fire resistant. A trade-off.
What size to use?
For kitchen fires and other small fires, 3-foot by 4-foot is convenient and common. For larger fires and to wrap people, 65 inches x 80 inches is standard. While the galley-size is handy, we like the idea of a large wool blanket for personal protection; in the summer we wear only light cotton clothing that provides no protection against fire.
We notice that some blankets were folded the same as you fold a blanket for the linen closet; in half or thirds, and then repeatedly folded over itself. This is takes too long to untangle, particularly in the larger sizes. Instead, your fire blanket fold accordion style, as you do a paper map; Z-fold on the long axis, and then Z-fold the other way. Grab a corner and it pops out flat.
Grease fires require special attention. First, fry food safely. Dont fry food underway or anchored where there are wakes, use the minimum amount of oil, place a suitable lid on the counter next to the skillet before you start, and never leave the pan unattended. Although many authorities show pictures of a blanket being placed over a burning pan of grease, the Netherlands Food and Consumer Product Safety Authority issued a statement that fire blankets should not be used to extinguish a grease boilover fire, because in most of their tests the grease soaked through the blanket, setting the blanket on fire. The solution is to always cut the fuel first and then to place a lid on the pan. If the fire is large, wrap your arm in the blanket to place the lid, and then place the blanket over the whole mess. If you are thinking of using a wet towel instead of a fire blanket, remember that the water in the towel will react with the hot grease, causing the fire to explode; make certain the lid is over the pan first.
All of the fire blankets reviewed are rated as single-use because of the potential for damage.
Wrap your hands behind the edge of the blanket (many provide tabs for this purpose) and hold it in front of you to protect your face and arms. However, you may also need to reach somewhere hot to close a valve or grab a flaming cushion and throw it over the side. A heat and flame resistant pair of gloves-either oven mitts or leather work gloves-can come in very handy. Keep a pair laying on top of the blanket. You can use them for other things, but always returned.
If possible, get the towel (and yourself) wet. This is particularly helpful if you are wearing long pants and long sleeves, getting wet from head to toe will reduce the chance of burns and clothing catching on fire. A wet towel can protect your hands and arms.
There are hundreds of NFPA-certified products out there, all of which will do the job. We inspected, but did not test any of these products, instead relying on the NFPA testing program. As soon as you buy it, unpack and re-pack the blanket; one of the samples we examined appeared to have been returned and was misfolded.
Small NFPA blankets
A large blanket is awkward in tight spaces. Its easy to imagine pulling a flaming pan onto yourself in a crowded galley, while wielding a large, heavy wool blanket. Both examples have black tabs for deploying and holding the blanket, which is required by ASTM standard.
This fiberglass blanket measuring 39-inches by 39-inches is one of the least expensive blankets on the market. It weighs very little and comes in a compact vinyl cover. It meets the bare minimum standard for a fire blanket.
Bottom line: We rated it a Budget Buy.
Measuring 39 by 39 inches this blanket is slightly bigger than the Inf-Way. Plastimo makes a variety economy priced products for the market. Their blanket is slightly more robust than the Inf-way, and comes in a sturdy rigid plastic case that can be mounted in a conspicuous location near the galley stove.
Bottom line: This blanket is compact yet still large enough put out an onboard fire before it gets out of control. It is our Best Choice.
Large Blankets (NFPA certified)
The larger blankets measure about 5 feet by 7 feet. Small is good in the galley, but what if you need to cover a larger fire or wrap a person with burning clothing? Big can be better, and while fiberglass is more heat resistant, wool is better for wrapping. There is a trade off here.
Measuring 60 by 72 inches, this fiberglass blanket is similar in construction and design to the Plastimo blanket. The chief difference is that it is larger and it is stored in a vinyl pouch.
Bottom line: We rate it as a Recommended buy for those who want a larger NFPA blanket that folds compactly.
Measuring 66 inches by 80 inches and made of wool, this is essentially a gray U.S. Army blanket that is flame-retardant treated and packed in a vinyl wall pouch. It is more expensive than a basic NFPA blanket of the same approximate dimensions.
Bottom line: We rate it as Recommended for those who like the dual purpose nature of a wool blanket.
Even if you have a fire blanket, you might need something more. Because they are not NFPA certified, and there is no real consistent standard for construction, you can’t be certain of performance. However, we did test these alternatives, primarily to offer some guidance to those sailors who do not yet have a dedicated fire blanket, or might not have one on hand.
Generic cotton towel (wet)
NEVER use a dry cotton towel to suppress a fire. You will light the towel on fire and make things worse. A wet towel (wrung out), on the other hand, proved very fire resistant, at least until it dried. There are downsides. A wet towel may cause a grease fire to splatter or fireball, so make certain the lid is on the pan. Second, the towel may require re-wetting; get a bucket of water and add water as needed.
Bottom line: Wet towels are valid back-up strategy.
US Army blanket
Made from 100 percent wool and treated with a flame retardant chemical to supplement the naturally flame retardant character of wool, we found no difference in performance vs. the wool fire blanket. Although this is not NFPA certified, weve made a special place in our safety gear locker for our US Army blanket.
Bottom line: A wool Army blanket meets serves two purposes, a criteria we like to apply to anything that goes on our boat. We rate it as Recommended.
When fire strikes, rapid but cool-headed response can make all the difference. In the case of an engine fire in a cramped space, a fire extinguisher, particularly if discharge though a fire port is possible, is probably the only practical response.
However, in many less complex fires, a fire blanket and water represent practical approach. We like the fiberglass blankets for their compact size; great for the galley area and engine room. However, we also recommend having at least one full-size wool blanket on board-either a fire blanket or a genuine wool US Army blanket-for larger fires and for personal protection.