By Bill Adams
Raisin Squad kibitzing in the firehouse kitchen was the original theme for this column. However, it morphed into another of my favorite topics: non-compliance to, and not understanding, the National Fire Protection Association NFPA 1901 Standard for Automotive Fire Apparatus. One geezer accused me of being anti-NFPA. Another said whenever I query the NFPA it’s like I’m abusing a rented mule. It’s not intentional.
A friend asked me to evaluate his purchasing specifications for a new rig. We both know he writes specs around one manufacturer. We’ve played this game before. It’s our way to keep in touch, talk fire trucks, and swap firehouse gossip. Well, what do you think about them? he asked. That was a mistake. (All underlining mine for emphasis.)
One specification requirement was: “The apparatus shall be designed with due consideration to distribution of load between the front and rear axles. Weight balance and distribution shall be in accordance with the recommendations of the National Fire Protection Association.” There’s no problem with that requisite although it was like ripping a scab off a healing wound. However, it gave me an opportunity to bloviate. Bloviate means “to discourse at length in a pompous or boastful manner.” Old people do it quite often.
Another requirement was: “The bidder shall make accurate statements as to the apparatus weight and dimensions.” It was like the 1993 movie Groundhog Day—I addressed front-to-rear weight distribution ratios 10 years ago in a Fire Engineering article.
I already knew the answer but still inquired if this was the same specification used for his last purchase. It was. When asked if that previous manufacturer provided a front-to-rear weight ratio, he couldn’t remember but acknowledged the bidder said the rig was NFPA compliant. I was off and running! What the hell kind of answer is that? You’re buying a rig that’ll cost almost a million bucks and you don’t know what’s in the specs? How can you evaluate a bidder’s compliance to the chassis manufacturer’s front-to-rear weight ratio if he doesn’t tell you what it is? If you get more than one bid, how do you compare something you can’t define–or find? I think he knew I was just teasing. We kibitzed some, told a few more tall tales, and parted friends.
NFPA 1901
I believe most specification writers and fire apparatus and chassis manufacturers will not or can not accurately describe front-to-rear weight ratios. What are they? Are they in writing? Where can I find them? That isn’t asking too much.
Actual NFPA 1901 requirements should be acknowledged. Again, underlining is mine for emphasis. NFPA 1901 4.13.2 Weight Distribution, sentence 4.13.2.1*: “When the fire apparatus is loaded to its estimated in-service weight, the front-to-rear weight distribution shall be within the limits set by the chassis manufacturer.” It is important to note the weight distribution ratio is set by the chassis manufacturer—not the apparatus manufacturer. And, it isn’t a recommendation as my friend’s specification said.
NFPA 1901 Appendix, sentence A.4.13.2.1 explains why maintaining a safe front-to-rear weight ratio is important: “The distribution of the weight between the front wheels and the rear wheels should be a major consideration, because improper design will seriously affect the handling characteristics of the fire apparatus. Too little weight on the front wheels can cause a front-end skid and, on bumpy roads, can cause the front of the fire apparatus to veer from side-to-side. At the very least, it would be difficult to keep the fire apparatus under control. Too much weight on the front wheels reduces the traction of the rear wheels and can result in a rear-end skid or difficulty in traveling over unpaved roads or in mud.” Sounds like common sense.
NFPA 1901 4.20 Data Required of the Contractor, sentence 4.20.1 Fire Apparatus Documentation lists documents manufacturers have to supply when delivering new apparatus. Under item (g): “Chassis weight distribution in pounds (kilograms) with water and manufacturer-mounted equipment (front and rear).” This is an ambiguous statement. My interpretation is manufacturers only have to provide actual weights on each axle “as delivered.” It says nothing about documenting the front-to-rear weight ratio that must be maintained when the rig is loaded to its in-service weight as mandated in 4.13.2.1*.
Caution
NFPA 1901 Appendix, sentence A.4.13.3.1 states: “It is the responsibility of the purchaser to properly load the fire apparatus and place equipment to comply with the GVWR, the front-to-rear weight distribution, and the right-to-left load balance requirements of this standard.” What does that mean? I think it means the fire department is obligated to comply with that unknown front-to-rear weight distribution ratio that no one can seem to define or find!
What does it really mean? If Engine 2 is responding to an alarm and skids out of control slamming into a car full of personal injury lawyers you might want to have your ducks in order in case you’re questioned under oath.
*Who wrote the purchasing specifications for Engine 2?
*Do you know the NFPA 1901 required front-to-rear weight ratio for Engine 2?
*Did you put that in your specifications?
*Did you verify the manufacturer met that requirement when you accepted his bid?
*Did you verify the actual front-to-rear weight ratio after loading Engine 2 before you placed it in service?
Dump Truck or Fire Truck?
Some manufacturers and their vendors can be vague and even evasive when answering questions about front-to-rear weight ratios. Some will state their “ratios” comply with Federal Department of Transportation (DOT) “guidelines”—which are really laws. Is it too obtuse to ask the vendor to provide a copy or a link to them?
From the 2012 Fire Engineering article: “Several decades ago, apparatus manufacturers and dealers referenced a publication called the National Truck Equipment Association’s (NTEA) Handbook, which had “recommended” or “allowable” weight distribution by percentage of gross vehicle weight (GVW) per axle for various types of commercial chassis such as conventional, tilt-cab, tandem, and so forth. It is unknown if any custom fire chassis manufacturers use or refer to the NTEA Handbook today. The NTEA did not respond to a request for information. Another unknown issue is whether or not the front-to-rear weight distribution varies with the application of the apparatus—i.e., pumper, tanker, aerial, and so forth. Ask your sales representative what the front-to-rear weight ratio is for your new apparatus. Demand it in writing. Require it in your specifications.”
Also from the article: “Specifying and operating safe fire apparatus is important. If the fire service can be held accountable for ‘maintaining a front-to-rear weight distribution ratio,’ whatever entity mandated that requirement should be equally accountable in clearly explaining what it means and how to find it. No fire department should be subjected to intense public scrutiny because of unavoidable circumstances.”
Although they should, not every apparatus manufacturer and vendor is up to speed on each NFPA 1901 requirement. However, if they sit on the NFPA’s Technical Committee on Fire Department Apparatus, they and every member on it are fair game. If they voted to adopt the requirement, they should be able to explain it. Ask. Good luck.
