Chassis Components, Engine Company, Fire Department

Big Pumpers

Issue 2 and Volume 12.

If you think big pumps have no place in rural situations, think otherwise. Big fires need big water, no matter where they are located.

Big pumps can be defined as 1,500 gpm or larger, above that threshold intakes are added. The larger capacity pumps have dual inlets because larger suction hose becomes too big and awkward to handle.

Rural fire departments are seeing the migration of “Big Box Stores” into their communities and many towns have older village “downtown” block buildings. These structures need large fire flows.

Educational facilities have been added to older colonial and early settlement communities and are usually constructed on the fringes of an older, antiquated water system. A bigger pumper strategically located could be used for regional water supply, not for “in-town” fires.

Consider The Future

Even if your community has not experienced a commercial development boom, consider future community growth and changes, which may require big pumpers.

Another reason to consider the value of big pumps is national security. If a major water system is wiped out, larger pumps can be brought in to augment the water supply while repairs are being made.

Fireboats were used extensively after the September 11 attacks and are in many contingency plans for waterfront cities.

During a San Francisco earthquake, waterfront fireboats were used with large diameter hose to supply water to the city cisterns.

Many old “Rail Hubs” have older construction and older water systems. A downtown fire increases the need for defensive firefighting, exposure protection, and large water volumes. A large capacity pump at a static water supply and 5- or 6-inch LDH hose can supplement the water flow greatly.

Determining Needs

There are a number of formulas used for figuring needed fire flows. Take one of your larger hazards and determine what is needed for fire flows and water supply. Can it be done with what you have today?  Will a mutual aid company help?  Is a new larger capacity pump needed?

When considering fire flows, here is a good analogy. If you are out hunting and spot a big, trophy 12-point buck, what are you going to grab, your trusty deer rifle or a Daisy BB gun to take it down? Think about that analogy when you are trying to darken down that big fire.

A large capacity pumper at the source of a static water supply is more effective than a small pumper. With a big capacity pump, more lines can be added and pressure increased to accommodate the necessary fire flow.

If a small pumper is at the source, it’s likely that the apparatus is already at capacity and increasing pressure is not going to increase flow when the demand is high.

It’s important to remember communications are paramount during pump relays, but often slips through the cracks. It is also important to note if it is an open or a closed relay. Many regions use the open concept to ensure the reserve water remains on hand, flowed into Fol-Da-Tanks and stored if the main attack pumpers shut down or reduce flows.

Whenever a pump relay is set up, and big water is flowed, it is critically important to remember the old saying “open slowly and close even slower.” This can save equipment and stress on the fire scene.

Larger capacity portable pumps can be workhorses for rural departments. In combination with a large capacity pumper, a remote off-road water source can be accessed.

With the use of large diameter hose (LDH) and Fol-Da-Tanks, water can be stockpiled and ready for a water shuttle. More than one portable pump can be deployed at a water source used to supply a relay pumper set up in a more accessible location on a main road. The portables can also be used in secondary water sources to supply apparatus during mop-up operations.

Factors To Consider

While there are many advantages to a big pump, there are many factors to consider when specifying one on apparatus.

Big pumps typically need big trucks to power them, and think about whether your roads and bridges can handle that kind of apparatus. Will it fit into the fire station? There has been more than one that hasn’t.

Consider what your neighbors have for pump capacity and supply modes, and consider their roads as well as you may have to respond with your apparatus.

Consider the staffing necessary to operate the big pumper. Personnel and firefighters will need to be trained and become knowledgeable of its operation and performance. Firefighters need to be drivers, not just “steerers” of the apparatus and drivers need to be trained as pump operators or engineers.

Big trucks are heavier and often longer. You’ll need to think about whether you’ll need an extra 40 acres to merely turn the rig around.

On Board Water

With increased pump capacity, it might be a good idea to have more on-board water, which adds significant weight to the vehicle. Another set of axles may be needed as tank size increases. The rule of thumb is that every gallon above 500 adds approximately 10 pounds to the apparatus.

Big trucks often cost big money. When drafting apparatus specifications, there are always the “got to have” items, the “nice to have” times and the reality checker, the “can’t afford to have” items. That extra axle for the big water just might be a budget buster.

Consider where your water sources are located. If they are off road, will a big truck make it to the drafting site without sinking to its axles?

Big trucks need improved access roads to water sources to handle the extra weight. If you want a big pump, think about updates and improvements to your rural draft sites using geo textiles and specialized fill to stabilize the road. Headwalls, road approaches, and simple things like cutting brush, mowing and marking drafting sites should be considered, and make special note of dry season water availability at draft sites.

It may be necessary to modify, update, or perhaps construct new water sites to accommodate the big pumper. Pay particular attention to the distance from the pump eye to the water surface. The National Fire Protection Association 1901 standard states that with larger capacity pumps, maximum lift is reduced to the 6- to 8-foot range with dual suctions.

Other considerations for accommodating a big pumper are simple by comparison. You’ll probably need some additional water appliances, fittings and maybe even some hose. Large diameter hoses will be needed, as will new suction hose that’s larger, longer and lighter. You might find a squirrel tail suction hose configuration (two or more suctions preconnected and looped on the apparatus) might be ideal.

Big fire means big water and even though big fires might not be a concern now, they might be in the future as development continues to affect rural areas.

When considering a big pumper, look beyond your town and district borders and work with others in the region.

Evaluate and select draft sites with care and attention to the apparatus that will use it. Big pumpers can’t get into small or muddy draft sites.

Above all else, remember that Mother Nature and a guy named “Murphy,” who has a bunch of so called laws, can do a lot to upset the apple cart. Always be ready with a “Plan B.”

More Fire Apparatus Current Issue Articles
More Fire Apparatus Archives Issue Articles