Apparatus Rollover: Handle with Air
Marriage Peril

It’s one of firefighting’s worst nightmares. An apparatus takes a corner too fast responding to a fire and rolls over, resulting in firefighter entrapment.

by Douglas Page 2003

Woolwich, Maine, volunteer firefighter Brad Gallagher was pinned in an upside down cab June 1 when an apparatus responding to a brush fire swerved to avoid a road hazard and rolled over on its roof when the edge of the roadway collapsed. Gallagher, who suffered only minor injuries, was trapped in the cab of the rolled-over tanker for over 15 minutes before colleagues freed him.

Not all firefighters are so fortunate. Truck rollovers claimed the lives of 26 firefighter in 2002, second to heart attack as the leading cause of firefighter death. More firefighters die in apparatus rollovers responding to fires than die from trauma induced by smoke and flames once on the scene, according to U.S. Fire Administration statistics.

That could begin to change, now that the first side roll protection system for fire apparatus has been introduced.

In April, Pierce announced the first side roll protection system for fire chassis. Using a microprocessor-controlled, solid-state sensing device, the system senses the exact moment of a side roll, and then provides instantaneous driver and first officer protection.

During a rollover accident, the driver’s head and body are often slammed upwards and sideways. Even seat-belted pasengers can be injured if their heads strike the side of the truck.

The Pierce system, called the Side Roll Protection System, automatically initiates a sequence of maneuvers to protect driver and passengers. First, the system tightens the seat belts. Then it lowers the front seats to their lowest position, locking them in place to eliminate movement. Lastly, the system deploys an inflatable tubular, side-curtain airbag across the driver and first officer's side windows to protects their head and neck.

Unlike automobile side airbags, which are meant to protect the driver or passengers during side impact, the Pierce system is designed specifically for truck rollover accidents where the danger is from the forces and motion inside the rolling truck.

The side-curtain airbag activates in a fraction of a second, then remains inflated for 10 seconds – judged to be enough time to protect occupants for the duration of a rollover.

The system was evaluated at the Center for Advanced Product Evaluation in Indiana, where engineers dressed crash dummies like firefighters then subjected them to repeated rolls in Pierce cabs. Head and neck injuries were reduced 97 percent for dummies weighing 170-215 pounds.

"We’re very impressed with this new safety technology," said Chief Ron Graham, Johnson County Fire Department, Prairie Village, KS. "Of the firefighter fatalities last year from vehicle crashes, I don't know if rollover protection would have reduced those numbers, but I would think it could have."

Graham said the Pierce rollover protection influenced their purchasing decision.

"Our truck bids were very close in price," he said. "One of the major factors that led us to purchase a Pierce fire truck was the rollover protection."

According to Pierce, this is the first side-roll protection system to be installed in Class 8 or above trucks. The company said the system will now be standard equipment on the Dash, Lance, and Enforcer chassis; Quantum models will be similarly equipped next year.

Pierce jointly engineered the system with Indiana Mills and Manufacturing, Inc., (IMMI), maker of vehicle safety restraints.

Hardware for the system was developed earlier. In 2001, an IMMI-designed Tubular Side Airbag System was introduced in Freightliner Century Class S/T and Argosy models, the first roll over application designed specifically for the commercial trucking market.

Truck rollovers are a matter of simple physics. When a fire apparatus travels in a curved path, centrifugal force acting through the truck’s center of gravity causes the vehicle to lean to the outside of the curve. The apparatus will roll over away from the center of the curve if the centrifugal force, which increases with speed and curvature of the road, is sufficiently large.

The measure of a truck’s ability to resist rollover is determined by its rollover threshold - the lowest value of centrifugal acceleration which causes the truck to tip over when driven steadily in a curved path. Rollover thresholds are frequently exceeded in the fire service, as apparatus’ routinely rush to incident scenes, often with tragic consequences.

A 10-year study of firefighter deaths showed that motor vehicle accidents account for nearly a quarter of all firefighters killed in the line of duty, according to the U.S. Fire Administration.

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Page writes a Technology Update column for Fire Chief Magazine. This article appeared in the August 2003 issue. 

Comments? Questions? Purchase Orders? douglaspage@earthlink.net
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