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Pump System Trends on Multipurpose Fire Apparatus

This is a rescue pumper with a large water tank and a rear-mounted pump. A unique features of this apparatus is the crosslays are located across the lower rear of the apparatus in what looks like a large rear platform bumper assembly.

By Gary Handwerk

Fire apparatus, from their earliest days, have always been evolving and changing to meet the demands of our communities. Today, because of budget cuts, consolidations, station closings, and fewer active volunteers, many departments now can only deploy a single apparatus on many alarms. Add to this that mutual aid has also been reduced or is taking longer to respond because of the same conditions.

Multipurpose apparatus have always been popular, but today they are being taken to a new level. For many departments, the “do everything” apparatus has become the indispensable tool. The key to any multipurpose apparatus is keeping the size of the apparatus down to a manageable level for maneuverability while having the tools, water, equipment, and personnel seating positions that are actually needed on board.

Since many departments now see fewer actual fire calls, the pump is one area where space may be available to save for other equipment or to shorten the wheelbase without losing capabilities. The typical traditional midship pump compartment is approx. 42 to 50 inches long and the full width of the apparatus. That is a lot of space for something you many only use at its full rated capacity a few times in its life. There are options, depending on the department’s needs, to have the pump performance required but reduce the footprint on the apparatus to do that job, and not lose any reliability.

To start this process, the first thing that must be determined, based on the department’s SOPs, run records, and culture, is how many of what size intakes and discharges are required and their locations. This will make selecting what pump configuration will work best easier, and the outcome will be better. Remember that the intakes and discharges can take up more space than the actual pump itself. Do not buy anymore than what is needed for the operational requirements of the apparatus.

The second question to answer is what size pump rating is required. ISO, the department’s history, and an analysis of existing potential fire treats and future needs will help answer this question. A bigger pump itself can take some extra space. But as the pump rating gets higher, there are more intakes and discharges required, and that means even more space requirements.

If the flow requirements are between a 1,500 and 2,000 gpm, one option for a pump system is to use one of the new, compact, fully manifolded midship pumps on the market. If the suction intakes and discharges are kept to only what must be there for NFPA and department SOPs, the midship pump box could be reduced to 28 to 34 inches long—a space savings of eight to 14 inches on most apparatus. One of the advantages to this concept is that the pump itself, pump-related systems, and operator locations are still traditional. For some departments, this will make the concept easier to sell to their personnel and their shops.

A rear-mounted pump is also a great option for reducing the pump system footprint. Again a 2,000-gpm is easily done. What takes up space on a rear-mounted pump is all the suction intakes and discharges along with the control panel. Depending on what a department selects, the space savings can be significant. The other space issue to be aware of on a rear-mount pump is how high the booster tank must be raised to clear the drive shaft running to the rear to drive the pump. Another area to investigate is where the operator’s station is located. Finding a safe zone for the operator that still provides good visibility can be a problem.

Another option is to use an unmanifolded midship pump rated for 1,500 gpm or less. These pumps allow the builder to custom design the manifolds and provide special compartment arrangements or locate the intakes and discharges lower than what is traditionally seen. This type of pump configuration can also be used to create a full-depth full-width and full-height right-hand side compartment, with no suction intakes or discharges on the right-hand side. The apparatus gains an extra right-hand full size compartment.

The final practical option is to use a PTO drive with a midmounted pump. There are three basic styles for this concept.

If the pump rating is 1,000 gpm or less, the pump will be small enough to keep it in between and below the chassis frame.

The second application is a 1,500-gpm package where the pump is mounted between the top of the chassis frame, is driven by a rear engine PTO (REPTO), and has a manifold system designed to keep the intakes and discharges low and out of the way.

The third configuration is the side-mounted pump, which is a PTO-driven pump below the chassis frame on the left-hand side with all the main intakes and discharges located on the left-hand side, outside of the chassis frame.

All of these pump configurations are being offered by many different apparatus builders nationwide. Since multipurpose apparatus are here to stay, what does the future hold for pump applications on this style of apparatus? The average fire apparatus will have fewer intakes and discharges compared with five years ago when there was a race to outdo the fire department down the street on their apparatus valve counts. Departments and builders will continue to find ways to package more equipment and capabilities on a single apparatus. Transmission PTOs driving the pump will continue to grow in popularity. The big old traditional fully manifolded midship pump will continue to lose market share. The 1,500-gpm rating will continue to be the most popular pump rating at least for the foreseeable future. So the final question is, “Are there opportunities in the market for new pump products or plumbing configurations of existing pumps?” The answer is yes.

GARY HANDWERK has been in the fire equipment industry for over 43 years and has worked for various fire apparatus or fire pump manufactures, holding positions in engineering or product management. He is involved as a consultant to several companies in the fire industry. He has been active with NFPA 1901, 1911, 1912, and 1925 for more than 25 years.

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