WHEN IT IS 30 DEGREES BELOW ZERO
It’s that time of year again. The author describes how in Minnesota, and in other northern states, it is especially hard to keep the apparatus rolling
Such subzero cold turns water to ice instantly — freezing hose lines, hydrants and equipment Frostbite is a serious threat to personnel, and extra crews for early relief are necessary.
At Brooklyn Park, Minn., last January, a house was destroyed by fire when the temperature was about 32 below and a strong wind created a minus-85-degree wind chill. Fire Chief Lyle Robinson, executive secretary of the Minnesota Fire Chiefs Association, says two of the first four fire fighters got back-spray from a hose line on their faces. They suffered instant frostbite and were hospitalized immediately. Hose lines froze while in use, and the pumps on two pumpers froze while pumping
Focusing on the problem
Only in recent years have fire departments and equipment manufacturers begun a concerted effort to address these difficult cold weather problems. While progress has been slow, the greatest success is in the design of engines anci pumpers.
Completely enclosed crew cabs with forced-air heaters have replaced many canopy cab pumpers around the state. The modern units prevent cold wind from whipping in around the sides of the canopy, and keep fire crews warm until they reach the fireground.
At Duluth, where icy winds blow in from Lake Superior, all pumpers are designed to prevent them from freezing, reports Assistant Fire Chief lames K. Heim. He says that features include enclosed pump compartments through which the warm engine exhaust is piped, and electrically heated gates that keep the thin water lines behind them from freezing.
levers—photos by the author.
—Minneapolis, FD photo by Doughs Dewey
Similar features are found on many of the newer pumpers around the state, and most manufacturers provide specific cold weather operating instructions.
Dipped in antifreeze
Heim explains that in Duluth and elsewhere, if an engine is on a cold fireground and not pumping, the operator churns the pump to keep the tank water warm. In addition, all pump caps are periodically dipped in antifreeze to enable removal in subzero weather.
St. Paul District Fire Chief Robert Heinen adds that portable pump cans containing water are either drained if a rig is going to be outside very long, or they are moved inside the engine where it is warm. AFFF cans, which can get slushy inside, and liquid-containing fire extinguishers usually get first priority inside, he explains.
The Minneapolis Fire Department has a new hydraulic tower ladder truck and pumper that is equipped with a 300-gallon foam tank. The tank is insulated and heated to help keep the AFFF warm in frigid temperatures.
One of the latest and most significant technical advances is the command cab pumper with enclosed top-mounted pump panel and crew area. One such unit was put in service by the St. Louis Park Fire Department in Nov. 1981, and it performed well during the harsh 1981-1982 Minnesota winter.
Enclosed pump panel
The fully enclosed and heated area behind the driver not only has a bench seat big enough to seat four fire fighters comfortably, but the enclosure also contains the pump operator station. The operator stands up, facing a desk panel that contains all gages and control levers No longer does the pump operator have to stand outside during a winter fire and freeze!
Built around the pump, the enclosure has windows on all sides for 360-degree visibility. The 40,000-Btu heater/defroster has a duct to the pump and central panel to keep water warm. Operator panel lights indicate which of the six 2 ½-inch discharges are in use.
The enclosure, which extends the height of the 1250-gpm pumper to 10 ½ feet is large enough to serve as a command post and contains run cards, maps, lights and radio equipment for that purpose
The enclosed pumper, with an automatic transmission, is fully compartmentalized. Ladders, generator and all equipment are all protected from exposure to snow, ice, slush, sleet, road salt and other winter weather hazards.
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COLD . . . Continued from page 29
Fighting ice-up
The major cold weather fire fighting problem for ladder trucks is ice-up of the extended aerial, cable drums, rollers, pulleys, etc., caused by spray from water towers and turret nozzles. The ice prevents the ladders from being lowered, and the weight of a heavy coat of ice can twist and damage aerial ladders. Thus, decisions regarding initial use and positioning of this heavy equipment in low temperatures must be made with anticipation of an icing problem.
Technology has attacked this icing problem with high-pressure steam, a method that is replacing the traditional solution of chipping and chopping the ice off by hand with axes and hammers.
Both the Minneapolis and St. Paul Fire Departments are among those that have over the past few years been using commercially available steamers that were developed for other purposes such as steam cleaning. These units have been adopted or modified for fire department use. Because of their potential, St. Paul’s Heinen believes manufacturers may in the future build some models especially for fire department use.
photo by the author.
“For example,” he says, “time is not as important in non-fire department applications. But we deal with emergencies and need to get our first line equipment back in service as soon as possible. So, I would expect to see steamers developed that will provide more rapid thawing.”
Another typical steamer shortcoming is that they should not be shut off in subzero weather because the thin copper steam lines inside the unit may freeze and ruin the expensive pump. Until this problem can be corrected, strict operating procedures must be followed.
Freeing frozen lines
Despite such limitations, steamers also are effective in helping to pick up frozen hose lines and to thaw frozen hose couplings. A hose line may become frozen either because the water inside turns to ice or because it becomes encased in pools of water that freeze in the street. Because it is very easy to damage frozen hose, Heinen emphasizes the need to prevent freeze-up. Heim of Duluth cites two cardinal rules that must be followed on a cold fireground:
- If lines are charged, never shut them off completely. Always flow an amount of water through them. The temperature determines how much.
- When lines are shut down, they must be uncoupled, drained and picked up immediately because the water temperature may not be much above freezing. No line is shut down until adequate manpower is available for pick-up.
Minneapolis Deputy Fire Chief Larry Moskalik points out that fire departments without steamers sometimes thaw small areas of frozen hose by holding it up to the hot exhaust pipe of a pumper. Thus, the middle of a 50-foot section of 2 ½-inch hose can be thawed enough to bend it into 35-foot lengths. Then the frozen hose can be put on a long flat bed truck for transport back to the station where it can be completely thawed and drained.
Torpedo tube heaters
Another approach is used at International Falls (often called the “Ice Box of the Nation”) located along the Canadian border. Fire Chief Ken “Buzz” Hultman reports that in extreme emergencies such as commercial building fires, they use portable Torpedo tube’ heaters with blowers. These are the propane-type with high Btu output that are used at construction sites and along the sidelines at football games.
They help keep fire fighters and equipment warm and can be used to thaw couplings, hose, ladders, pump cans and other items.
One method of preventing hose lines from freezing in pools of ice water on the street is suggested by a Minneapolis fire fighter who says boards and other material can be used to elevate the hose a few inches in those areas where pooling water is likely to freeze.
Heim says special attention must be given to prevent freezing of 4-inch hose that comes in 100-foot lengths.
“During the past 10 years, we have had to drag only one length back to the station to be thawed,” he explains. “Thankfully, there was a lot of snow and we were only two blocks from the station.”
In the Seventies, clothing manufacturers made a number of technological improvements to turnout gear, underwear and helmets so they do a much better job of keeping fire fighters warm. But Hultman of International Falls speaks for virtually all Minnesota fire fighters when he says a good pair of warm, waterproof and heatresistance gloves is still hard to find.
Gloves not suitable
Federal OSHA regulations specify that fire fighters must wear gloves that meet NFPA, NIOSH or OSHA standards. But gloves are not suitable for use in the severe cold that occurs throughout Minnesota.
While gloves normally provide greater flexibility because they allow individual finger movement, they are not as effective as mittens in keeping fingers and hands warm. With gloves, fingers become numb and inflexible when it is very cold. Therefore, the Minnesota OSHA has issued an interpretation that allows fire fighters to use mittens if they meet the glove standards required by the federal rule.
Fortunately, most Minnesota fire fighters are outdoorsmen and many have construction or similar work experience, so they know it is essential to keep all flesh covered in extreme cold because of the danger of painful frostbite. Once it happens, the affected area remains sensitive to cold temperature for many years.
Wear a mask
In addition, body heat escapes rapidly through exposed skin —usually the face. For this reason, many Minnesota fire fighters keep — or are required to keep — a ski or face mask handy in the winter.
The coldest period frequently is after the fire, during pickup. A helpful hint provided by Heim of Duluth is that exchanging icy, wet clothes and mitts for dry clothing makes a big difference. When the manpower is available, departments bring in fresh fire crews for pickup.
But even with the best of modern technology applied to cold weather fire fighting, the force of nature still is overpowering when it gets down to 30 below and a strong wind howls across an icy fireground.
