Beware of the Unintended Consequence
- By Jerry Laws
- May 01, 2003
AT first, it's hard to believe a simple red marker light presents a
significant fire risk. More than 80 fires documented since July 2001 prove it,
however. What is harder to believe is why these loading dock fires are a recent
phenomenon: because enforcement of a U.S./Canadian safety regulation enacted in
1968 finally began four years ago.
The National Highway Traffic Safety Administration requires three red
identification lights to be placed, centered, at the top of the rear end of a
trailer that is 80 inches wide or wider. Lights available in 1968 weren't easily
mounted in this location, so NHTSA didn't force trailer manufacturers to install
them. In April 1999 the agency made them mandatory. Burn damage to dock seals
and actual fires then increased dramatically, said officials at Frommelt
Products Corporation, a Milwaukee manufacturer of loading dock seals. One fire
of this type destroyed a food warehouse in Hillside, Illinois. "We're seeing it
grow, not going away," Frommelt President Paul Rowlett told me recently.
Frommelt's engineers saw evidence pointing to the ID lights, but how a
14-volt lamp could be responsible for the damage mystified them. Engineering
Director Chuck Ashelin and his team investigated the problem as they began
developing a fire-resistant dock seal. One factor is dual alternator systems
installed on many modern tractor-trailer rigs to power microwaves and other
in-cab devices for the drivers. Another is drivers' tendency to leave their
lights on while parked, he said.
In their tests, some standard ID lights reached more than 800 degrees
Fahrenheit within 30 minutes when compressed into a dock seal's foam pad.
Ashelin said the foam begins breaking down because of this heat, releasing
flammable gases and more heat; even if the trailer has left the dock, the foam
will "auto-ignite" above 800 degrees. "Conditions have to be just right," he
said, "but (auto-ignition temperatures) can definitely be exceeded with these
low-wattage lamps."
At least 200,000 seals, possibly 250,000, are in use today in the United
States with foam head pads vulnerable to this hazard, Rowlett said. Many
terminal managers are unaware of it. When they look for heat damage in their
facilities' pads, however, they invariably find it. The overall lack of
awareness in the industry is the real problem, he said, because dock fires
endanger personnel, product, facilities, and productivity.
He said professional firefighters don't believe this hazard is real when they
first hear of it. Neither did I. Raising awareness of the threat and of
fire-resistant alternative materials may be difficult, but Rowlett and his
colleagues are doing their best.
This article originally appeared in the May 2003 issue of Occupational Health & Safety.
About the Author
Jerry Laws is Editor of Occupational Health & Safety magazine, which is owned by 1105 Media Inc.