July 2007

Pump Talk

by Gary Handwerk

Specifying Pumps For Wildland Apparatus

Many western fire departments are well versed in wildland and urban interface requirement. Climate, population growth and terrain have driven them to develop specialized apparatus and equip many of their mainline apparatus to support wildland fires.

In some ways, wildland fire hazards are looked at in a different way on the western side of the U.S. The rest of the country has had some wildland apparatus, mostly state forestry service supported, and many individual departments have grass units or field pieces –small apparatus to support small fires.

What is changing for the eastern half of the country is urban sprawl coupled with droughts causing major wildland fires. Most weather experts and the United States Department of Agriculture (USDA) believe droughts will not be going away anytime soon.

So, with conditions prime for big fires, let’s plan for them and make good choices when we buy our next apparatus.

It’s this support and interface that creates innovative apparatus that we will look at. For many departments, especially on the East Coast, they are new ideas.

I am not advocating true, off-road wildland operations being accomplished with your new 40,000-pound, 430 hp, $450,000 custom pumper. What we are talking about is adding the ability to supply small amounts of water at pressures to remote locations to supply wildland fires and/or adding pump-and-roll capabilities for fires along roadways.

One of the most common ways to add wildland capabilities to a full pumper is to add a small, engine-driven pump in addition to the main pump. The current trend is for these pumps to be driven with a 26 hp diesel engine and mounted directly on top of the main midship pump. These pumps usually can supply flows up to 180 gpm or pressures over 300 psi.

Pump-And-Roll

With this configuration, you now have pump-and-roll and stationary pumping at low flows without operating the main pump. These small, engine-driven pumps guarantee optimum pump-and-roll performance while generating sufficient stationary performance for wildland operations.

Of course you can stationary pump with the main pump, as long as you are flowing some water. With any big pump – no mater what the design – if you operate for a period of time without flowing water you will overheat the pump. When you add in the significant heat generated by the truck engine and transmission, which is transferred to the pump by the engine auxiliary cooler system, the time to overheat the pump can be just a few minutes.

Protecting The Pump

The best way to control this is to guarantee water flow with an automatic pump recirculation line (also called a churn line) or by adding a thermo relief valve setup. The thermo relief valve works like a thermostat and will automatically open and close at a set pump water temperature – commonly 120 degrees Fahrenheit. It’s set at 120 degrees, not a limit due to pump design, but a limit as to how hot you will want your hose lines to be for the personnel to handle.

The other method of adding wildland capacity to a mainline apparatus is to install a small auxiliary pto-driven pump. These pumps are usually no larger than 250 gpm and are geared to provide pump and roll or stationary firefighting.

The goal is to have at least 100 gpm at 100 to 120 psi while the drive engine is operating at approximately 750 RPMs. This setup provides pumping performance at very low road speeds. The only drawback is you need sufficient engine power at idle to drive the pump.

A good example of this is Los Angeles County. That department equips its pumpers with high-pressure pto pumps, which can deliver 100 gpm at approx 180 psi at idle and which are set up with blow-off relief valves and high-speed pto disengagement systems for personnel and equipment safety.

Safety Issues

These added capabilities are not just installed on L.A. County’s pumpers, but on quints, tanker/tenders as auxiliary systems and even on straight aerials as the only pump system.

Auxiliary pump systems can be piped to select outlets, which are also capable of being feed by the main pump. This sub-manifolding is very common and can include Class A foam capabilities.

If you do feed outlets from different pumping sources, use check valves in each manifold supply line to prevent one pump from back feeding pressure into the other pump. This is an important safety feature, and it wasn’t a National Fire Protection Association (NFPA) requirement until the 2003 document. So, if you are using older apparatus with auxiliary pumps, it would be wise to have the check valves retrofitted. Without them, the backpressure can kill firefighters.

Another safety issue to be aware of when equipping an apparatus with an auxiliary pump system is the proper labeling of all controls, as well as the inlets and outlets. The last thing you want is to connect a hose to an outlet when you really wanted it connected to an inlet. This is another situation that can kill.

Ember Separators

In addition to adding an auxiliary pump system, don’t forget the wildland hose, adapters, nozzles and tools needed to support these operations. Another item sometime added to a pumper is an outlet to fill Indian cans or vest packs.

If you plan to use an older pumper in support of wildland operations, make sure the apparatus has ember separators installed on the truck engine air cleaner system. This is very important and often over looked. Current NFPA-compliant apparatus have this feature, but most mid ‘90s and older apparatus do not.

Paper air filters will catch on fire and can burn down the entire apparatus – a very difficult situation to explain to superiors.

Interface Apparatus

Another important consideration is many generators, some portable/trash pumps and some rescue tool power units do not have spark arrestor mufflers. Keep in mind, you’re there to put out fires, not start new ones. Make sure the arrestors are installed and working properly on all gasoline-powered equipment.

The other approach, instead of adding wildland capabilities to a mainline apparatus, is to build a combination or interface apparatus. In different parts of the country, they are called Type III, petrol apparatus, interface apparatus or middy pumpers, but they all have the ability to fight wildland or structural fires.

They typically have a 500- to 1000-gpm pump, and a 500- to 750-gallon tank and are built on a medium-duty chassis with a gross vehicle weight rate (GVWR) of 29,000 pounds or larger. The great debate in this class of apparatus is whether to buy a 4x4 or a 4x2 cab and chassis.

Some departments feel that 4X4 will get you in trouble because drivers will believe they can go anywhere. To make that decision departments need to answer whether the apparatus will be will be taken off road. I’m not talking about dirt roads, or driveways. I mean NO road.

Second, departments need to seriously examine who they have on the staff to drive off-road and who is trained to do so. Also, departments need to realize 4x4s are expensive, typically require a lot of maintenance/repairs and make the vehicle more difficult to drive because they are higher and less maneuverable. The short answer to the question is don’t buy a 4x4 if you don’t really need it.

Type III apparatus typically have large pto pumps, but often small pto or engine driven auxiliary pumps are added. Most of these apparatus have Allison 3000EVS transmissions, which are capable of driving 500- to 1,000-gpm pto pumps, but in most cases, at speeds too fast to make pump-and-roll effective to use. That’s why most of these apparatus have auxiliary pump systems.

Common In Europe

Another approach is to use a 4-to-1 hi/lo pump to give you 100 gpm at approximately 100 psi at engine idle. These pumps are common in Europe and produce high-capacity flows at 150 psi while at the same time producing small flows at 600 psi.

This class of apparatus is not easy to buy, as the balance between pumper and wildland apparatus must be carefully weighed and a good selection must be made.

Weight Limitations

Departments need to determine what will be carried, what jobs will be done and what are they willing to give up. It’s impossible to have everything, and typically space and weight limitations will be the problem. As has been said previously, designing your next apparatus should be based on the jobs it is intended to do and what resources are needed to do those jobs.

If you’re going to do interior structural attacks, get a least an NFPA 1901 500-gpm pumping system, and carry the equipment, turnout gear and self-contained breathing apparatus (SCBAs) and have the hand line capacity to do the job.

If you’re going after a wildfire, get the rig that will do that job, or make sure your apparatus will do both effectively.

Editor’s Note: Gary Handwerk is global pump product manager for Hale Products. He has been involved with the fire service industry for 36 years working for various fire apparatus or pump manufacturers and has been a member of the National Fire Protection Association (NFPA) Fire Apparatus Standards Committee for 15 years.