By Bill Adams
Over morning coffee, the Raisin Squad was addressing the day’s major problems – inflation, threat of war, rising school taxes, re-paving the streets in town and what’s for lunch at the senior center. One vertically challenged geezer started moaning and groaning – again – about the chair heights at the kitchen table. We pay him little attention.
Bill Adams
But he was on a roll – not even coming up for air: “I looked in the cab of that new rig but the damn step was too high to get in.” We told him only active members belong in the cabs. He kept complaining “I pulled myself up on the rear step but them folding steps are so far apart I couldn’t get higher.” One white hair told him to sue his parents for giving him short legs. “I can’t – they passed years ago.” We said he shouldn’t be climbing that high or he’d get a nosebleed. “There’s actives in here shorter than me. They gotta have a hard time too.”
Then out-of-the-clear came this: “Yesterday I used the handicap facility at the center. My legs were dangling in the air. It was higher than them damn fold down seats in the that pumper you sold us 30 years ago.” I said I didn’t sell it. “It don’t matter; you were on the committee. Why can’t you people build fire trucks for short people?” I left.
NFPA 1901
Stumpy (his new nickname) made a couple good points. The first is the step heights on fire trucks and the second is the seat height in the crew cabs. The National Fire Protection Association NFPA 1901 for Standard Automotive Fire Apparatus says under 15.7.1.1 “The maximum stepping height shall not exceed 18 in. (460 mm), with the exception of the ground to first step, which shall not exceed 24 in. (610 mm) when the vehicle is loaded to its estimated in-service weight.”
Those are maximum distances. How did the NFPA come up with those figures? What’s the best comfort height for climbing access steps on a fire truck? Can a purchaser specify steps less than 18-inches apart and the first one less than 24-inches from the ground?
Risers
A step riser is the height from one stepping surface to the another. Researching them on the web shows numerous regulatory, or recommended, or industry accepted standards including some from OSHA, the NFPA, and the International Building Code. They address workplace stairs, commercial stairs, steps for the fire service and general public, homes, step ladders, and you name it.
Nothing says if their requirements have to be are in synch. One OSHA requirement says step risers should be no less than 6 inches in height and no more than 7.5 inches; another says 4-inches to 7-inches. The step risers in most houses are around 7½-inches.
NFPA 1931 and Common Sense
NFPA 1931 Standard for Manufacturer’s Design of Fire Department Ground Ladders under 4.1.3.6* states: “Rungs shall be uniformly spaced ±3 mm (±1∕8 in.) on centers that are between 305 mm and 356 mm (12 in. and 14 in.).”
I venture the NFPA assumes firefighters in full protective clothing will be climbing up and down ladders as well as climbing