By Bill Adams
When purchasing a pump-equipped fire truck, there’s a reasonable expectation that a quality and professional piping installation will be supplied.
What is expected may not be what’s delivered. National Fire Protection Association (NFPA) 1901, Standard for Automotive Fire Apparatus, Chapter 16, Fire Pumps and Associated Equipment, only specifies performance and minimum sizes for some of a rig’s piping. The design, degree of engineering, level of workmanship, and materials to be used are left to the apparatus purchasing committee (APC) to specify. To the best of my knowledge, there is not a documented “right way” or “wrong way” to plumb a fire pump. Purchasers commonly rely on apparatus manufacturers (OEMs) to provide piping installation verbiage to incorporate into their purchasing specifications. Be advised that some OEM specifications are more detailed than others. Regardless of the specificity of the verbiage, when a purchaser publishes an OEM’s suggested specification, the purchaser owns it.
|1 A unique, one-of-a-kind, and obviously field-engineered tank-to-pump line on a rig. It appears the booster tank was either ordered incorrectly or was one that was in stock. Regardless of the numerous parts and pieces to make the connection, the rig did pass a tank-to-pump flow test. Not pretty-but it works. (Photo courtesy of the author.)|
Does Terminology Matter?
In a competitive bidding environment, whatever is written in the purchasing specifications becomes the precedent-the minimum requirements that all bidders must meet. A fire chief stating, “Brand A’s plumbing is third rate; my kid could have done a better job,” or “Brand B’s piping job is unprofessional; it is unacceptable,” may not be legal grounds to disqualify a bid. One way to get the best value for monies expended is to fairly evaluate product and proposals by comparing apples to apples.
Some APC members don’t care about or can’t be bothered with piping particulars, blindly accepting whatever a preferred vendor is selling. They should care because they might have to describe what a particular piping component is and why it was, or was not, specified. Visualize explaining to the mayor-in a public forum-that you don’t know what model 3203 widgets are but you really need them on your new fire truck. Your preferred vendor might not be there to bail you out. Good luck. An alternative is to leave piping particulars out of the specifications and hope for the best. Purchasers should be aware of what could be provided inside their new pump house.
|2 A look into the front of a pump house. The downward arrow shows a 2½-inch valve facing the street-side pump panel. It turns 90 degrees toward the front of the rig and then turns 90 degrees toward the curb side with a straight run of pipe. It then turns 90 degrees upward to the top of the pump house. The horizontal arrow shows another 90-degree turn facing toward the back of the rig to a street-side rear discharge. The upward arrow shows one method of supporting a pipe. (Photos by Allan Smith, fire apparatus sales manager, Colden Enterprises, unless otherwise noted.)|
A Piping Primer
Many apparatus piping specifications contain ambiguous terms such as “heavy-duty” and “flexible connection.” More definitive, but not specific, are generic terms such as “victaulic couplings” and “roustabout connections.” When words are capitalized, a Victaulic coupling and a Roust-A-Bout fitting become trademarked products of the Victaulic Company, headquartered in Easton, Pennsylvania (photo 4). If a specification only requires a flexible connection, bidders can provide whatever they want, including an offshore-manufactured, mongrel brand, lookalike roustabout fitting. A roustabout fitting clamps together two “bare ended” pieces of pipe by physically “biting into” the pipes’ wall material. Roustabouts are commonly used for repairs in older buildings’ fire sprinkler systems. It is irrelevant if the purchaser expected a Victaulic Model 77 coupling-a two-part clamping collar that holds piping together by fitting into machined or rolled grooves on the pipes’ ends. Bidders only have to comply with what is written in the purchasing specification. Specifying a manufacturer and model number creates a quantifiable baseline on which proposals can be evaluated. A requirement or expectation not in writing does not exist.
Unless defined in purchasing specifications, what constitutes heavy-duty pipe is in the eyes of the beholder. Most hard piping in a fire truck is Schedule 10 or Schedule 40. Schedule 40 pipe has a thick wall dimension, it weighs more, it can be threaded, and it can have grooves machine-cut into it for use with victaulic-style couplings. In the construction trades, Schedule 10 pipe has been derogatorily called “tubing” or “thin wall” because it cannot be threaded or machine-grooved. Roustabout-style fittings cannot be used on thin-walled pipe.
|3 Another pipe run from a similarly located valve to a street-side rear discharge on a different rig. The pipe run to the curb side is angled up and provided with a rolling offset with three fittings and filler pieces before it is directed toward the rear of the rig, as shown by the upper horizontal arrow. The complicated and labor-intensive pipe run is because of the front bumper discharge with the flexible hose indicated by the lower vertical arrow. The upward facing arrows show where piping for the side steamer inlets is welded to a ram’s horn fitting on an end-suction pump.|
Grooves for victaulic connections on Schedule 10 pipe must be rolled or pressed into the piping. The process causes the displaced metal to protrude into the pipe’s internal diameter, which in turn creates friction loss at each groove. The obstruction is similar to the internal “lip” created when cutting pipe with a cutter wheel. In the piping trades, reaming pipes to eliminate lips and burrs is a standard practice when doing professional installations. It can’t be done to rolled grooves.
Apparatus vendors seldom discuss friction loss in piping installations. Some fire departments are unaware it even exists in a rig’s piping. They ought to if they expect the best flow when drafting. Ditto for supplying an appliance that’s performance level is contingent on a certain inlet pressure such as a portable foam eductor. When pumping a single across-the-board discharge pressure, the actual flows from like-sized discharges at the front bumper, in crosslays and speedlays, or piped to the rear of the apparatus may differ, but that might not matter to some people.
The wall thickness of two-inch Schedule 10 stainless pipe is 30 percent thinner than Schedule 40. A benefit is it weighs almost 30 percent less. A four-inch Schedule 10 stainless pipe wall thickness is 50 percent less than Schedule 40 and correspondingly weighs almost 50 percent less. Both can be welded. Although the thinner pipe is easier to handle in the field, OEMs can claim Schedule 10 piping installations are heavy-duty, providing Schedule 10 meets the verbiage in a purchaser’s specification. Ask what the difference in cost between the two is. Then ask if one is warrantied for a longer period than the other.
Be Fair to OEMs
Traditionally large midship pump houses have been purposely shrunk in size or eliminated to provide more compartmentation and shorter wheelbases. The cost savings of an OEM’s standard preengineered piping system can be negated by purchasers requesting off-the-wall customization-regardless of it being reasonable or not. As an example, specifying a valve control or piping connection at an OEM’s nonstandard location can create havoc inside a pump house (photos 2, 3, and 6).
|4 The upper arrows show what appears to be hard piping being sleeved through a booster tank. It is misleading. They are actually flexible hoses similar to one indicated by the horizontal arrow. I wonder if the blue colored and black colored flex hoses meet the same specifications.|
Additionally, individual chassis attributes such as four-wheel drive may require modifications to preengineered piping configurations to meet NFPA 1901 height criteria (photos 3 and 8). In-the-field engineering to fit 10 pounds of piping into a five-pound envelope may be inevitable. Flanged fittings, thin-walled pipe, welded filler pieces (spacers), bolt-on valves, and flexible connections facilitate new piping installations. They also make repairs quicker and easier. The days of mechanics leaning into a pump house to make repairs with a pair of two-foot pipe wrenches are over.
The quotes below were copied from publicly available OEM proposals and purchasers’ requests for bids. They are shown to illustrate the specificity, or lack thereof, of piping installations offered by various manufacturers that are acceptable to and specified by some purchasers. Italicized questions and comments in parentheses are mine. This article only addresses the piping supplied by the OEM-not the pump manufacturers.
- “All inlet and outlet plumbing, 3.00 inches and smaller, shall be plumbed with either stainless steel pipe or synthetic rubber hose reinforced with high-tensile polyester braid.” (Who decides which one to use?)
- “All suction and discharge lines of two inches or larger shall be constructed of a minimum of Schedule 40 galvanized steel pipe.” (Ask if there’s a difference in cost between galvanized and stainless piping installations. Any difference in warranties?)
- “All piping for discharges shall be stainless steel using stainless steel fittings.” (A four-inch stainless steel Victaulic coupling can cost 225 percent more than a cast Victaulic coupling. Are they sure they want stainless Victaulic couplings?)
- “All suction and discharge lines (except pump manifolds) one inch and larger shall be heavy-duty stainless steel pipe.” (Schedule 40, Schedule 10, or does it really matter?)
- “All auxiliary suction and discharge plumbing, related fittings, and manifolds shall be fabricated with Schedule 10 stainless steel pipe, brass, or high-pressure flexible piping with stainless steel couplings. Galvanized components and/or iron pipe shall NOT be accepted to ensure long life of the plumbing system without corrosion or deterioration of the waterway system. Where waterway transitions are critical (elbows, tees, etc.), no threaded fittings shall be allowed to promote the smooth transition of water flow to minimize friction loss and turbulence. All piping components and valves shall be nonpainted unless otherwise specified. All piping welds shall be wire brushed and cleaned for inspection and appearance.” (When is a waterway transition “critical enough” that threaded fittings can’t be used?)
- “All fabricated piping shall be a minimum of Schedule 10 stainless steel for superior corrosion resistance and decreased friction loss.” (Are types 316, 304, and 303 stainless piping all acceptable? Corrosion resistance to certain environments or resistance to seawater may require a specific product. Ask vendors to substantiate “decreased friction loss in stainless piping.” I’ve never heard of it.)
- “The fire pump plumbing system shall be of rigid stainless steel pipe or flexible piping with stainless steel fittings.” (What does the purchaser expect or will it accept? Does “rigid stainless steel pipe” mean only threaded pipe, or does it include grooved pipe?)
|5 The arrows show two discharges hard piped beneath the booster tank to the rear of the apparatus.|
Piping Flex Joints
- “A minimum of one (1) grooved pipe coupling shall be furnished in this assembly to allow for flex and serviceability.” (See photo 2.)
- “Where vibration or chassis flexing may damage or loosen piping, or where a coupling is required for servicing, the piping shall be equipped with victaulic or rubber couplings.” (Rubber?)
- “Where vibration or chassis flexing may damage or loosen threaded pipes, Victaulic or Roustabout couplings shall be used.” (Is one less expensive to purchase and install?)
- “All piping shall be properly supported and braced to prevent movement of piping other than what is allowed by the Victaulic couplings to compensate for apparatus flexing (photo 3).” (Who or what defines properly supported? Victaulic couplings on Schedule 40 machine-grooved piping allow a slight deflection in a pipe’s direction. Schedule 10 rolled grooved piping allows a deviation only half as much. It is not unheard of, or illegal, to use multiple short pieces of grooved pipe rather than an engineered welded offset to achieve a dimensional change in direction or elevation. Does it matter?)
|6 The inside of a pump house with six inline push-pull control levers with a seventh in the foreground. Observe the control rods’ orientation (how level) beyond the universal joints. It’s no wonder some are harder to pull than others. Simple control linkage, uncomplicated piping, less expensive installation, and easier repairs down the road could be possible by letting an OEM design its own pump panels.|
- “All flexible discharge lines and bleeder lines, downstream of respective valves, shall be reinforced high-pressure hose assemblies with stainless steel or brass end fittings (photo 2).” (What defines a flexible discharge line-one that’s sleeved through a tank or goes to a crosslay or is piped to the front bumper?)
- “Synthetic rubber hose reinforced with high-tensile polyester braid.” (Is the flexible helix-wire-reinforced piping mentioned below more expensive than the polyester braid? Is the hose tested with the couplings attached?)
- “High-pressure flexible helix-wire-reinforced piping with a minimum burst pressure of 1,200 pounds per square inch (psi) may be used in some areas to minimize friction losses. All flexible piping couplings shall be high-tensile-strength stainless steel.” (Why is it used in some areas and not in all areas to reduce friction loss? Or, is it used because it is an easier or only way to make the installation? Ask.)
- “The high-pressure flexible piping shall be black SBR synthetic rubber hose with 300-psi working pressure and 1,200-psi burst pressure for flexible piping sizes 1.5 inches through four inches. Sizes ¾ inch, one inch, and five inch are rated at 250-psi working pressure and 1,000-psi burst pressure. All sizes are rated at 30 inches HG vacuum. Reinforcement consists of two plies of high-tensile-strength tire cord for all sizes and helix wire installed in sizes one inch through five inch for maximum performance in tight bend applications. The material has a temperature rating of -40°F to +210°F. The stainless steel full flow couplings are precision machined from high-tensile-strength stainless steel. All female couplings are brass. Mechanical grooved and male ¾-inch and one-inch couplings are brass. A high-tensile-strength stainless steel ferrule with serrations on the I.D. is utilized to assure maximum holding power when fastening couplings to hose.” (Ask for a spec sheet for the hose being supplied.)
|7 This photo shows what appears to be an engineering error requiring a double-width weld between two fittings. Double welds may not be ethical but they are not “illegal” per NFPA 1901.|
I have no preference for if stainless steel, plain steel, galvanized, brass, or flexible hose is used for piping. Nor do I have a preference for one type of flexible connection. It is the APC’s responsibility to determine what is best for its application. Purchasers have to rely on the experience, expertise, and honesty of vendors in recommending purchasing specifications. Specification verbiage should accurately reflect the installation and products acceptable while taking care to not specify unnecessary components. You might only receive what you actually asked for and not necessarily what you thought you specified or expected. A prebid conference might help ensure purchasing specifications are fair and equitable for all parties. Although there is no written standard or guideline for plumbing the pump on a fire truck, there should be more to a piping installation than just passing a third-party certification per NFPA 1901.
BILL ADAMS is a member of the Fire Apparatus & Emergency Equipment editorial advisory board, a former fire apparatus salesman, and a past chief of the East Rochester (NY) Fire Department. He has 50 years of experience in the volunteer fire service.
|8 Another ram’s horn suction fitting on an end-suction pump where the OEM used several angled filler pieces welded in place to achieve an orientation compatible with the chassis components.|