Speccing a new pumper: Where to begin – Part 1
Review NFPA 1901, define the pumper’s mission, calculate weight, consider pump types and CAFS, and more
Let’s change our approach this time around, looking at the application of NFPA 1901: Standard on Automotive Fire Apparatus requirements from a somewhat different perspective – that of a pumper committee that’s been charged by its fire chief to develop the specifications for a new pumper.
Understanding NFPA 1901
NFPA 1901 (2016 edition) defines “the requirements for new automotive fire apparatus and trailers designed to be used under emergency conditions to transport personnel and equipment and to support the suppression of fires and mitigation of other hazardous situations.”
The standard applies to new fire apparatus that meet the following criteria:
- Gross vehicle weight rating (GVWR) of at least 10,000 lbs. (4,500 kg)
- Designed for use under emergency conditions to transport personnel and equipment and to support the suppression of fires and mitigation of other hazardous situations
- Contracted for on or after Jan. 1 (of the current edition of NFPA 1901)
Applying the standard
NFPA 1901 provides the requirements for new fire apparatus, but the purchasing fire department ultimately determines how it satisfies the requirements. This is the specifications portion of the fire apparatus procurement process.
For example, Chapter 5 (Pumper Fire Apparatus) states that a pumper is required to have a pump capable of flowing 750 gpm (3,000 L/m). A fire department writing specifications for a new pumper could satisfy that requirement with any of the following options:
- Midship-mounted centrifugal pump
- Midship-mounted PTO pump
- Rear-mounted centrifugal pump
And the fire department has the flexibility to ultimately purchase the new pumper from the manufacturer that provides the best price while meeting the department’s specifications.
Where to begin
The best place to start is by reviewing the requirements listed in the most current edition of NFPA 1901. Like all NFPA standards, NFPA 1901 is revised on a five-year cycle, and because things change rapidly in the fire apparatus manufacturing world, the committee must work from the most current information.
A good place to start is with Appendix A: Explanatory Material. Why? Because this is the section where the technical committee for the standard has the freedom to provide additional information and context for specific sections of the standard.
For example, again in Section 5, we find the following requirement for a water tank on the apparatus: “5.5* Water Tank. The pumper shall be equipped with a water tank that meets the requirements of Chapter 18 and has a minimum certified capacity (combined, if applicable) of 300 gallons (1100 L).” The * after the section number means there is applicable material available in Appendix A. In this case, that additional material looks like this: “A.5.5 Fire departments should carefully evaluate their water supply needs and the available water delivery systems when considering water tank size. The minimum tank size of 300 gallons (1100 L) might not meet the needs of the department.”
Fire departments servicing areas with wide hydrant spacing or no hydrants should strongly consider increasing the water tank size. The department should choose a water tank size that will best support efficient and effective fireground operations.
Defining the pumper’s mission
The primary consideration in the design of a new pumper should be defining its mission. In Appendix B, NFPA 1901 provides the necessary questions for the committee to address:
- What are the typical types of responses for the pumper (e.g., structure fires, wildfires, automobile accidents, medical assistance, rural water supply)?
- What does the pumper’s response environment look like (e.g., older city downtown with narrow streets and alleys, suburban neighborhoods, garden apartments, rural roads, major expressways)?
- How many riding positions will be needed?
- What size pump is needed?
- How much and what sizes of hose are needed?
- What EMS capability is needed?
- What type of chassis for the pumper (e.g., commercial, or custom)?
- What type of chassis configuration (e.g., conventional, cabover, cab forward, rear engine)
- Are there any size or weight limitations due to fire station, roads, bridges, terrain or neighborhoods?
- How much money is budgeted for the purchase?
- How long is this pumper expected to be in service?
Staying within the pumper’s GVWR
NFPA 1901 places great emphasis on fire apparatus that, while fully equipped, remains below its listed GVWR.
The portable and fixed equipment (e.g., generator, water tank, light tower) carried on a pumper all add a significant amount of weight to the vehicle’s chassis. As such, the committee should carefully consider these factors:
- Legacy equipment that will be carried
- Proposed new equipment that will be carried as the apparatus goes in service
- New equipment that might be carried in the future
These components can represent the most concentrated and heaviest load elements on the vehicle, so it is critical that they be identified and situated early in the specification and design process so that the new pumper has:
- Good load distribution
- Good balance (both front to rear and right to left)
- An acceptable center of gravity
Weight and cube calculator
The Fire Apparatus Manufacturers Association has a free resource, the Fire Apparatus Equipment Weight and Cube Calculator, which committees can use to track the portable equipment it plans to carry on the new pumper.
The calculator provides the estimated weights and volumes for typical pieces of firefighting equipment so that you can calculate the total weight of your equipment and determine the total compartment volume needed to store it. Using the calculator will help the committee ensure that the specifications it develops for the new pumper keep the vehicle and all its equipment below the vehicle’s GVWR.
The most important aspect of any pumping fire apparatus is its ability to transfer water from a hydrant, onboard water tank or static source to the seat of the fire.
Start developing the specifications for the fire pump by determining the most common water flow requirements necessary for your department to provide fire suppression services for your community. A good place to acquire the data is the Insurance Services Office (ISO). ISO should have the information on required fire flows for the community.
Ask these questions during the planning process so you have a solid understanding of what the pumper’s capabilities:
- What’s your community’s available water supply? Does your department rely primarily on the municipal water supply? Do you have areas where you need to draft from static water sources?
- What are the building and occupancy demographics (e.g., single-family residential and multi-family residential, big-box retail, industrial and manufacturing) for your community?
- What fire flows will you need most often? Different occupancies and buildings can have vastly different fire flow requirements.
- What is the “lay of the land” for your response area: urban, rural or wildland-urban interface (WUI)? Is there forested land, mountainous terrain or low-lying areas subject to flooding?
- How many hoselines, and at what fire flow, does the department expect to operate from the pumper?
- What is your available staffing to operate those hoselines?
What type of pump?
Pump manufacturers have responded to pump needs of fire departments with an assortment of new products, from 1,500 gpm PTO-driven pumps, to centrifugal pumps with new casting designs and attachments designed to fit in smaller spaces, to high-pressure models useful in pump-and-roll applications.
They are also using customized non-manifolded fire pumps that have customized suction and discharge manifolds, instead of large and bulky full cast mid-ship pumps, in order to save up to 50 to 70 inches of space behind the apparatus cab.
Smaller pumps that take up less space on the apparatus means fire departments can specify apparatus with shorter wheelbases, easier to reach hose compartments for cross-lay and speed-lay hose loads, and pump-and-roll capabilities for all engine types.
New generation of PTO pumps
Many fire departments today are looking for fire apparatus that can support the department's multi-hazard mission, a mission where the fire suppression component has become a lower-frequency and lower-magnitude (fewer big fires) requirement.
This newer generation of PTO-driven pumps provides them with a practical and economical pump capable of providing high water volume for those large fires that still happen occasionally.
PTO-driven pumps have fewer parts, so they present fewer headaches when it comes to repair and regular preventative maintenance. Many departments see this as a significant issue, especially if they do not have a full-time service department to maintain their vehicles.
The simpler design and operation of a PTO-driven pump make them a popular choice with apparatus design committees, especially when it comes to the training of new driver operators, many of whom don't have the prior mechanical knowledge of their predecessors.
A favorite saying of the late Alan Brunacini, retired fire chief of the Phoenix Fire Department, is that if you are building a pumper today without a compressed air foam system (CAFS), it's already obsolete.
Why did Chief Brunacini have that opinion? Likely because he had a great appreciation for how much fire suppression capability CAFS could add to any sized piece of fire apparatus.
For example, a CAFS fire stream has a 20-1 expansion ratio when used according to the manufacturer's recommendations. That means that for every gallon of water being used, 20 gallons of finished CAFS solution can be delivered to the fire.
What if a 300-gallon water tank on a Type I pumper could yield 6,000 gallons of CAFS fire suppression solution? That’s equal to six Type I pumpers, each with 1000-gallon water tanks.
The higher BTUs produced by today’s fuel loads – which are high in synthetic materials – require that fire suppression crews apply more water for longer periods of time. The technology behind CAFS continues to improve, and the price of CAFS for fire apparatus continues to drop.
Looking ahead …
We’ve discussed the application of the requirements of NFPA 1901 from the perspective of a pumper committee that’s been charged by its fire chief to develop the specifications for a new pumper. But we’ve only covered half of this topic. In the next installment, we’ll cover how to ensure that the new pumper is more than just a truck with a pump.
[Resource: How to buy apparatus (downloadable eBook)]