Apparatus, Equipment, Features

Cantankerous Wisdom: A Diatribe on Suction Inlets and Custom Cabs

By Bill Adams

A diatribe can be defined as a tirade, rant, criticism or discourse. Call it what you like. Did you ever wonder what the hell some people were thinking when they designed a fire truck? Regardless of whether they are vendors or purchasers, sometimes you’ve got to ask yourself if decisions are really based on sound judgment and common sense. In reviewing a blueprint for a pumper, there was a scaled figure of a firefighter in the rear view. At head level, there was a five-inch large-diameter hose (LDH) inlet. It is doubtful you’ll find a more difficult, senseless, and unsafe but “legal” location to connect a supply line.

Visualize attempting to disconnect the same line that is not fully drained. A water-filled 100-foot length of five-inch LDH can weigh more than 950 pounds. The 5½ feet of water-filled hose from ground level to the inlet could weigh more than 50 pounds. And you are disconnecting it at or above head level, good luck—don’t get hurt. A consideration seldom addressed is having a “smaller statured” or “close to retirement aged” firefighter attempting those connections. Another consideration is whether a helping hand will be required. Can two firefighters safely access the connection? If your purchasing specifications only stated “One (1) rear five-inch large-diameter suction inlet shall be supplied,” some of your members could end up with a nosebleed, losing a couple teeth, or suffering a concussion. They may not be impressed with your spec writing expertise. Are you more concerned with the least expensive way for the manufacturer to run the piping or with providing a safe and functional “working environment” for your firefighters?

Heights and Sizes
In mentioning a “legal” height to make a connection, the National Fire Protection Association (NFPA) does not address heights for suction inlets. NFPA 1901, Standard for Automotive Fire Apparatus, does address height for discharges but only says that any discharge larger than two inches located more than 42 inches from ground level must have a minimum 30-degree elbow. It has no such requirement for the height of a suction inlet from ground level or that it must have a minimum 30-degree elbow. Be aware that if you don’t spec it, you might not get it. And, you’ll have no recourse. You lose. Read Section 16.6, Pump Intake Connections.

Another bewildering NFPA requirement—or omission—is the lack of addressing suction inlet size at the pump operator’s panel. Sentence 16.7.9.1 specifically says there shall be no discharge larger than 2½ inches at the pump operator’s panel. That makes sense and it’s obviously for safety’s sake, as noted in the appendix, A.16.7.9. The very next statement in the appendix says it would be ideal “having no intake or discharge connection at the operator’s position” but it does not prohibit them. That’s interesting. How smart is it having your reproductive organs inches away from a suction inlet that could be receiving 1,500 gallons per minute (gpm) at a pressure of 100 pounds per square inch (psi)? It’s about as smart as having three crosslays discharging at 200 psi directly next to or above your head. Which body part is more important to you? Good luck. I hope the hose or couplings don’t fail.

More Cabs and Common Sense
A career firefighter commented on December’s Cabs and Common Sense article, saying that the front and rear cabs are too cramped, considering the personal escape ropes, gloves, traffic vests, small hand tools, and the like being carried in both turnout coat pockets and bunker pants saddlebag pockets. NFPA 1901 Chapter 14, Driving and Crew Areas, is worth reading. It states that each seating space must be a minimum of 22 inches wide at shoulder level with a minimum 18-inch-wide seat cushion. That’s not much room. You can move the motor out of the cab, however rear and midengine configurations are not that popular. One manufacturer has moved the motor rearward, giving the officer and driver a little more room—that makes sense.

I wonder if it’s possible to increase the height of the cab and raise the seats to be level with the motor’s dog house. Look at European cabs, which are predominantly commercial chassis. Their raised roofs go over the entire front and rear seating areas. That makes sense. Maybe they are on to something. After all, Europeans are the ones who came up with sexless couplings, large-diameter hose, and rear-mounted aerial ladders.

The raised roofs on American-made custom cabs are a continuing topic for conversation and evaluation. In looking at several manufacturers, three have the raised portion extending partially over the front seating area while four of them have the raised roof portion over the rear crew area only. If the reason for a raised roof is for crew safety, comfort, and ease in accessing and getting out of the cab, how come the officer and driver are not afforded the same level of comfort and safety? Ask your favorite vendor to explain that one. Why spend the extra bucks to raise the roof if it’s not going to benefit your entire crew? One manufacturer offers raised roof height options that range from five to 24 inches. I wonder why.

BILL ADAMS is a former fire apparatus salesman, a past chief, and an active member of the East Rochester (NY) Fire Department. He has more than 45 years of experience in the volunteer fire service.