Cantankerous Wisdom: Plates, Sheets, and Specs

By Bill Adams

The more I age, the more frustrated I get reading fire truck specifications. Years ago, specs were short and sweet, right to the point, and easy to read. There was no second guessing what was being said. You didn’t have to call the fire chief to ask what he really wanted. You knew. Back then, no one minced words. It’s a different ballgame today. Spec writers should be penalized for each meaningless word they slide into a set of specs. The same goes for every word they use that has multiple meanings. A bid estimator shouldn’t have to waste time calling up a prospective customer to find out what is meant by heavy duty or top-of-the-line, or industry standard. Yep, fine them 10 bucks for each unnecessary word.

Consider the words plate and sheet. A plate is a dish you eat off of. That’s simple enough. Now a sheet can be a piece of paper or a piece of linen. Sentence content and common sense gives you an idea of if you’re going to read something or take a nap. When plate and sheet are used in a set of purchasing specifications to describe the metal in body construction, all bets are off. Some fire department spec writers may not realize what they’re describing. Sadly, some vendors might not either. 

Found in a set of specs: “The understructure floor shall be of minimum 12 gauge welded stainless steel plate. All compartment panels and body side sheets shall be entirely premium grade stainless steel (Type 304L).” Being from the old school, I interpret that the spec writer wants any alloy of 12-gauge stainless steel plate for the floor and any gauge of 304L (low carbon content) sheet stainless steel for the rest of the body. It seems logical. Heavy plate steel is appropriate for flooring, and, because a metal gauge wasn’t specified for the body and compartments, thinner sheet steel appears acceptable to bend, form, and shape the body. If I were a bid estimator, I would have priced it as such.

Then, I started reading between the lines. What the heck does “understructure floor” mean? Is there a separate floor beneath the compartment floor? Or, is the understructure floor actually the compartment floor? It says the underfloor structure is welded but it doesn’t say the compartments and body are. Maybe they can be bolted. Do they expect both the compartments and the body to be 12-gauge? Damn, I gotta spend a dime to call and find out.

Actual verbiage from various OEM and purchaser generated specifications: 

  • All compartment panels and body side sheets shall be fabricated entirely from 12 gauge stainless steel (Type 304L).
  • Body and compartments shall be fabricated of 304L stainless steel.
  • All compartment panels and body side sheets shall be entirely premium grade stainless steel (Type 304L).
  • The apparatus body shall be fabricated of 304-2B marine grade brushed stainless steel.
  • The entire apparatus body shall be constructed of 304 marine grade stainless steel with a #4 annealed and polished finish on both the interior and exterior surfaces. 
  • Body and compartments shall be fabricated of corrosion resistant, low carbon austenitic, brushed and painted 304L stainless steel. 
  • The apparatus hose body and compartments are to be fabricated entirely of 12-gauge thickness, “flat-leveled” type 304 sheet stainless steel, with a #4-polished (brushed) 2-side finish.

Are these people specifying and bidding the “same stuff”? I doubt it. They’re not literally describing the same thing. When researching plate and sheet steel, one source said stainless steel sheet is cold rolled in thicknesses between 1 mm and 4 mm. Stainless steel plate is hot rolled in thicknesses greater than 3 mm. Why can’t people standardize how they specify thickness? Besides specifying thickness in gauge, decimals, fractions, and millimeters, some specs call stainless hot rolled, cold rolled, finish rolled, stretcher leveled, and flat leveled. 

Zac Zitelman, lead product designer at CustomFIRE Apparatus was kind enough to explain metals so a novice like myself can understand them. Zitelman says, “All 304/304L sheet stock starts as hot rolled. Thicknesses from 3/16 inch (4.76 mm) to 4 inches (101.6mm) are available as hot rolled and are referred to as plate.” According to another source, “Cold rolling takes hot rolled steel and rolls it again for tighter thickness tolerances and improved surface finishes.” Zitelman adds, “Cold rolled is available in thicknesses from 26-gauge (0.48mm) to 7-gauge (4.76mm). Cold rolled is referred to as sheet.”

Zitelman also alludes to the fact that sometimes spec writers use the wrong terminology. He says, “I think the spec that you are reading is misusing the term plate. And, they may be referring to a body part as a ‘side sheet’ just like CustomFIRE used to and not necessarily that the material is sheet metal itself.” Who would have thought sheet describes both a body part as well as how raw metal is delivered? Is it possible a spec writer could misuse a simple word like plate? Some may think this tirade is splitting hairs. Misinterpretation and misuse of verbiage may cost a dealer a sale and may result in a fire department getting a rig built out of something it didn’t really want. This is too much for me to comprehend. The topic is being turned over to the Raisin Squad for their comments. You’ll get the white hairs’ report the next time.

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.

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