Two workers were killed when a gas-fired, walk-in powder coating oven exploded in California. The building and its contents were destroyed.(Photo: AP/Wide World Photos)
NFPA Journal®, July/August 2011
Natural gas explosion kills two
CALIFORNIA — Two men, ages 38 and 35, were killed in an explosion in a gas-fired, walk-in powder coating oven. One died of blunt force trauma, and the other was electrocuted.
The walls of the single-story, wood-frame building in which the oven was located were made of insulated sheet metal. The roof was also metal. The building measured 125 feet (38 meters) by 125 feet (38 meters), and the oven measured 20 feet (6 meters) by 11 feet (3 meters). There were no fire detection or suppression systems.
Investigators found that the pressure regulator of the natural gas line had been bypassed, allowing approximately 53 psi of natural gas to feed into the operating oven, where it was ignited by the auto igniter.
The explosion destroyed nearly one-third of the building. The building, valued at $500,000, and its contents, valued at $200,000, were considered total losses.
Smoking materials, alcohol lead to fire death
OHIO — A 53-year-old man was found unconscious by a relative in a two-car garage, in which he repaired cars, after a fire started by smoking materials ignited an upholstered sofa.
The single-story garage, which measured 24 feet (7 meters) by 24 feet (7 meters), had concrete block walls over a concrete slab and a wood truss roof covered by asphalt shingles. It was detached from a single-family residence in which the victim did not live, but where he occasionally stayed overnight. The garage did not have any automatic fire detection or sprinklers.
The victim was last seen shortly after midnight and appeared to be intoxicated. When a family member checked on him the next day, he discovered the remains of the fire, which had extinguished itself after consuming the sofa, and called 911 around 3 p.m. The victim’s body was 8 feet (2 meters) from the sofa and had not been burned or suffered any trauma. There were no lights on in the garage and no sign of work activity. All the garage doors were closed.
Investigators suspect that the victim was near the area of origin, became disorientated, and was overcome by smoke. In addition to alcohol intoxication, the victim had a history of asthma, which may have been a factor in his death. The coroner determined that he died of smoke inhalation.
The building, valued at $15,000, and its contents, valued at $5,000, sustained only $50 in damage.
Occupant dies in smoking fire
OHIO — A 37-year-old man died in his first-floor apartment when he was unable to escape from a fire started by smoking materials.
The three-story, 51-unit apartment building was 145 feet (44 meters) long and 40 feet (12 meters) wide. It had concrete block walls and floors, as well as a wood-deck roof. Smoke alarms had been installed, but there were no sprinklers. The apartments, which measured 15 feet (5 meters) by 12 feet (4 meters), had their own bathrooms but no kitchens.
A third-floor resident called 911 at 4:27 a.m. to report smoke coming from his light fixture. When firefighters arrived, they did not see any flame or smoke outside the building. As they spoke with the third-floor occupant, however, they noted light smoke on the first floor and began checking the apartments on that floor. Finding heavy black smoke in one unit, they began suppression operations and quickly knocked the fire down using a short burst of water.
During a secondary search, they found the victim partially under a dresser, a cardboard box, and some window treatments. Investigators said it appeared that the smoke alarm alerted the occupant, who tried to escape through window above the dresser. During the attempt, the dresser tipped over onto the victim.
The building, valued at $500,000, had $1,000 worth of damage. The apartment’s contents, valued at $1,500, were destroyed. An autopsy revealed that the victim, who was under the influence of prescribed medication and marijuana, died of smoke inhalation.
Unattended cooking ignites deadly fire
VIRGINIA — A 50-year-old women and a 7-year-old girl died of smoke inhalation and burns when food left cooking unattended on the stove started a fire in the kitchen of their single-family house.
The one-story, wood-frame house, which was 42 feet (13 meters) long and 25 feet (11 meters) wide, had wood-paneled interior walls and a wooden truss roof covered by asphalt shingles. There were no smoke alarms or sprinklers.
A passerby on an adjacent street saw the fire and called 911 at 11:48 p.m. Firefighters arrived within six minutes of the alarm and found smoke and flames coming from three sides of the building, threatening homes on either side of the house. They were told that two victims might be in the house, but crews could not get into the building until they knocked the heavy fire down. When they finally entered the house, they found both victims in a middle bedroom, severely burned.
Investigators determined that a pot of vegetables left cooking on the stove overheated and ignited, and that the fire spread from the stovetop to other combustibles in the kitchen. There were no smoke alarms to alert the occupants to the fire, which spread quickly to other areas of the house.
The house, which was valued at $43,400, and contents, valued at $15,000, were destroyed.
Sprinkler controls unattended cooking fire
ARIZONA — A sprinkler controlled a fire that began when a 14-year-old girl left a pan of cooking oil heating unattended on the stove in the kitchen of her family’s apartment.
The wood-frame apartment building, which had an asphalt shingle roof, was equipped with smoke detectors and a wet-pipe NFPA 13R sprinkler system that provided a local alarm.
Firefighters received a 911 call reporting the fire at 8 p.m., and arrived to find that the sprinkler system had operated as designed and extinguished the fire before it could spread. They stopped the water flow and performed salvage operations in the apartment of origin and the unit below.
The building, which was valued at $150,000, sustained an estimated $5,000 in damage. Its contents, valued at $25,000, sustained a $7,500 loss. There were no injuries.
Medical oxygen a factor in fatal smoking fire
OHIO — A 66-year-old woman who used medical oxygen died of injuries she sustained during an early morning fire that began when a cigarette ignited the mattress cover and sheet on the bed on which she slept.
The three-story, six-unit, wood-frame apartment building, which measured 43 feet (13 meters) by 72 feet (22 meters), had a brick veneer and an asphalt-shingled roof. A hardwired smoke alarm with battery backup had been installed in the apartment of origin, but it did not operate. The building had no sprinklers.
The fire was reported around 6 a.m., and arriving firefighters discovered that the fire had already burned itself out after filling the apartment with smoke. They found the victim dead of smoke inhalation, with some burns about her mouth and nose in the outline of an oxygen mask.
On the mattress, they noted a cigarette lighter, an empty pack of cigarettes, and two ashtrays with cigarette butts in them. Only two-thirds of the mattress and box spring was burned, but that portion was burned down to the springs.
Investigators determined that a cigarette ignited the woman’s bedding and that the medical oxygen contributed to the fire. The smoke detector in the apartment was connected to the electrical system, but it did not appear to have functioned.
The building, valued at $245,000, and the apartment’s contents, valued $10,000, sustained $5,000 in damage.
Cigarette fire kills one
INDIANA — A 46-year-old man who lived in an eight-unit assisted-living facility died of smoke inhalation during a fire started by improperly disposed of cigarettes.
The one-story, wood-frame apartment building had a wood roof covered by asphalt shingles. A hardwired ionization smoke detector had been installed, but it did not operate.
A passerby noticed the fire and called 911 at 11 a.m. Shortly afterward, firefighters arrived to find that the fire had almost burned itself out. While searching the premises, they discovered the body of the victim, who had succumbed to smoke near the rear doorway of the unit while trying to escape.
Investigators found smoking materials and ashtrays on the victim’s bed and floor, and determined that the fire started 4 to 6 hours before it was detected when a smoldering cigarette ignited a recliner’s arm rest. The fire spread to a closet and a shelf before burning itself out. Alcohol intoxication appears to have been a contributing factor in the victim’s inability to escape.
Leaking propane ignites after piping damaged
NEW HAMPSHIRE — The occupants of a single-family home managed to escape a fire started by a low-order explosion in their basement.
The three-story, wood-frame house was 38 feet (12 meters) long and 26 feet (8 meters) wide. Hardwired smoke alarms were located on each floor, including the basement, and in each bedroom, and they operated as designed. The house had no fire suppression system, although a single sprinkler had been installed above the furnace in the basement.
Shortly before the explosion occurred, an employee of a lawn-care company mowing the lawn hit piping leading from a propane tank to the gas-fired water heater in the basement with a thud, causing the pipe to leak. One of the occupants of the house looked out the window and saw the employee looking at the gas regulator. The crew left within minutes, and the explosion occurred shortly afterward, as one of the occupants was taking a shower in an upstairs bathroom.
Firefighters called to the scene at 10:15 a.m. arrived to find that the occupants had safely evacuated the house and had shut off the propane line. They also found the sprinkler operating above the furnace. Water from the sprinkler and from plastic pipes that had burned through extinguished the fire.
Investigators discovered a break in the gas line near the elbow where it entered the basement and determined that the demand for hot water caused the water heater to start and ignite the leaking propane
The house, which was valued at $171,400, and its contents, which were valued at $100,000, sustained damage estimated at $15,000 and $10,000, respectively. There were no injuries.
Restaurant fire causes million-dollar loss
MISSOURI — A Mexican restaurant on the upper level of a two-story, L-shaped building and a game store below it were damaged by an early morning fire that burned undetected until a passerby saw smoke coming from the back door and called 911 at 6:34 a.m.
Firefighters arrived two minutes after the call to find smoke coming from the roof vent. The incident commander ordered several units to set up for a coordinated interior attack, and after stepping inside, firefighters heard the fire traveling through the walls and ceiling. The engine crew waited by the front door with a hose line while another company ventilated the rear of the restaurant.
Additional companies provided back up, removing walls and ceilings between the restaurant’s seating area and the kitchen, where the fire was concentrated.
Investigators determined that the fire started in the kitchen in a machine used to warm tortilla chips, but they could not discover why.
Heavy black smoke filled both levels of the building and destroyed both the structure, which was valued at $650,000, and its contents, valued at $350,000. There were no injuries.
Sprinklers control fire in stadium
MINNESOTA — Two sprinklers controlled a fire in a large stadium that started when maintenance personnel spilled gasoline while refueling a pressure washer.
The stadium, which was six stories high, was designed so that portions of it were open to the elements. The property was protected by a monitored wet-pipe sprinkler system.
Maintenance staff was washing down seating on the fifth level near a concession stand with a gasoline-fired, portable pressure washer. When the workers tried to refuel it, they spilled some gasoline, and the hot motor ignited the vapors. Heat from the fire activated two overhead sprinklers.
The fire department was notified at 10:52 p.m., and firefighters arrived within two minutes to find that the sprinklers had already extinguished the blaze. Fire damage was limited to the immediate area, but water flowing down a freight elevator shaft damaged suites several floors below.
Loss estimates were not reported. There were no injuries.
Sprinkler extinguishes incendiary school fire
ARIZONA—A single sprinkler extinguished an incendiary fire at an occupied school, limiting property damage in the $4.3 million structure to roughly $43,000.
The single-story school, built in 2008, was constructed of masonry walls on a concrete slab with a prefabricated wooden truss roof covered by wood decking and a built-up roof surface. The interior partitions of the building were wood-framed. The school’s fire alarm system, which included smoke detectors, and its wet-pipe sprinkler system were monitored by an alarm company.
Someone started the fire in the men’s bathroom by setting paper towels alight in a large plastic waste barrel. Smoke from the fire tripped the smoke detector and the sprinkler, which extinguished the fire before firefighters responded to the 8 a.m. alarm.
There were no injuries.
Sprinklers control fire in stable
MASSACHUSETTS — A sprinkler operated and spared a horse stable significant fire damage when it extinguished a fire in the tack room.
The single-story, wood-frame stable, which measured 125 feet (38 meters) by 75 feet (23 meters), had a dry-pipe sprinkler system with a water flow alarm that was monitored by a municipal fire alarm system.
A fire alarm sounded at 3:06 a.m., alerting the fire department, which dispatched apparatus, as well as the night watchman, who called 911 at 3:11 a.m. The police routed the watchman’s call to the responding firefighters. On arrival, fire crews found that the sprinkler had already suppressed the fire in the tack room, although heavy smoke was still present throughout the structure.
Investigators determined that the fire was started by a submersible electric heater used to keep water in a plastic pail from freezing. The heat from the appliance ignited the pail, and the fire spread to other combustibles before the sprinkler activated.
Property damage to the stable was estimated at $5,000.
Sprinklers spare municipal garage significant loss
WISCONSIN — Two sprinklers controlled a fire in a diesel-powered, wide-area rotary lawn mower that was parked in a municipal parks department garage, limiting property loss to the mower.
The single-story, drive-through garage, which was constructed of masonry and metal, had interior stall parking. A monitored wet-pipe sprinkler system protected the property.
The fire was first detected by a garage employee, who tried unsuccessfully to extinguish it with a portable fire extinguisher. When the fire grew too large to handle, he left the building and called 911 from his cell phone at 3:35 p.m. Right after he finished the call, he heard the water flow alarm sound, indicating that two sprinklers had activated.
Firefighters arrived within seven minutes to find moderate smoke coming from open bay doors on two sides of the building. The first-in engine company established a water supply and learned from an employee that “something blew up in the back.” He also told firefighters that the structure contained flammable liquids.
Advancing a large-diameter hose into the building, fire crews saw flames 8 to 10 feet (2 to 3 meters) high about 30 feet (9 meters) inside the building being held in check by the sprinklers. Because fire debris accumulated at the floor drain, hydraulic fluid that had leaked out was floating above the water. They used a dry chemical extinguisher to complete extinguishment, then ventilated the building and shut down the sprinkler system.
Investigators determined that the 11-year-old commercial riding mower had been parked in the garage after being used during the day and that the fire started in or near the mower’s engine compartment. However, they were unable to determine the exact cause of ignition.
The fire spread to the mower’s plastic engine shroud and to a 35-gallon (132-liter) plastic hydraulic reservoir and a 40-gallon (151-liter) diesel fuel tank, both of which melted, further fueling the fire. Although the fire burned portions of the lawn mower, the sprinklers spared the vehicles parked on either side of it.
The lawn mower had a replacement value of $73,000. Portions of the building’s steel roof located above the fire, as well as interior ceiling heaters and lights, were damaged, but loss estimates were not reported. There were no injuries.
Sprinkler extinguishes fire from natural gas leak
OHIO — A single sprinkler extinguished a fire that began when natural gas piping feeding a commercial, rotary-style bread oven in a grocery store bakery dislodged, allowing natural gas to build up and ignite.
The grocery store was located in a single-story building that measured 175 feet (53 meters) by 248 feet (76 meters). The building was constructed of concrete block walls over poured concrete floors. Unprotected steel trusses formed the roof structure, which was covered with a metal deck roof and built-up roof surface. The property was protected by a monitored wet-pipe sprinkler system.
When investigators found that the gas piping’s drip leg had fallen off, without damaging the threads, just beyond the regulator but before the igniter, they determined that the piping had not been properly tightened. Gas leaking from the joint was ignited by an open flame in the oven’s burner chamber. As the temperature rose, it destroyed the oven’s wiring and other controls, causing a sprinkler above the oven to open.
The store, valued at $2.4 million, and its contents, valued at more than $1 million, sustained an estimated loss of $7,500.
Firefighters treated one of the store’s employees on scene for minor smoke inhalation.
Sprinkler controls fire started by oily rags
ILLINOIS — The contents of a garage and storage area in a mixed-use strip mall ignited and burned until a sprinkler operated and controlled the fire before firefighters arrived.
The single-story building, which measured 200 feet (61 meters) by 75 feet (23 meters), was constructed of concrete block walls over a concrete slab with a metal truss roof and a built-up roof deck covered by a rubber membrane. The mall had a wet-pipe sprinkler system connected directly to fire dispatch.
The sprinkler flow activation alerted firefighters to the blaze, and they immediately responded to complete extinguishment and to ventilate the strip mall.
Investigators determined that oily rags, left in a pile in the storage area by a business owner who had been refinishing a deck, spontaneously ignited and that the fire grew until it produced enough heat to activate the sprinkler.
The building’s contents were damaged, for an estimated loss of approximately $2,000. The building itself was undamaged. There were no injuries.
Single sprinkler controls fire in nursing home
ILLINOIS — Firefighters responding to an automatic alarm at a nursing home found a sprinkler controlling a fire that started in a commercial dryer and spread through ductwork to a rooftop ventilation unit.
The single-story, 80-bed nursing home was protected by a monitored wet-pipe sprinkler system and a fire alarm system that automatically transmitted an alarm directly to the local fire department.
The department received the alarm at 6:15 p.m. and responded with two engines, a ladder truck, and a district fire chief. While en route, the department received a follow-up phone call reporting that the fire was a dryer fire, and the incident commander upgraded the response to include an additional engine, ladder, and district fire chief.
Arriving fire crews found smoke showing outside the building. By the time the second group arrived, black smoke was coming from the roof. A fourth engine was dispatched as first-in companies supplied the sprinkler system, advanced a hose line into the building, and began to assess conditions inside the structure.
One group of firefighters located the fire in the basement laundry room, where the sprinkler was holding it in check. Another crew on the roof used a hose line to extinguish the flames that had spread through the dryer’s ventilation duct.
Damage to the property and its contents was estimated at $50,000. No one was injured.
Sprinklers limit roof fire at assisted living facility
OREGON — A dry-pipe sprinkler system limited property loss and prevented injuries during a rooftop fire at an assisted-living center. The staff initially thought the alarm was false and cancelled the first fire department response. However, subsequent alarms and water flowing from the sprinklers led staffers to call 911 at 10:02 p.m.
The two-story, Type-V building, which covered approximately 70,000 square feet (6,503 square meters), had a pitched wood truss roof covered with composite asphalt shingles. The facility had four individual wings, each separated by two-hour fire barrier walls with protected openings. The exit corridors, which also had protected openings, had a one-hour fire rating, and all the building’s stairs were enclosed. The property was protected by a monitored dry-pipe sprinkler system, as well as a manual fire alarm and monitored smoke detection system.
The facility was holding a Fourth of July celebration outside on a patio, igniting legally bought consumer fireworks from a table that staff members had covered with aluminum foil. Fireworks were also being used elsewhere in the neighborhood.
When the smoke detection system first sounded at roughly 9:44 p.m., facility administration assumed that the haze in the building was a normal byproduct of the fireworks that had entered through open doors and windows. The monitoring service was called and the fire department response canceled.
When the detection system sounded again a short time later, however, the smoke was heavier. A broken water pipe was reported on the second floor, but the leaking water was actually coming from operating sprinklers.
The fire department response was resumed at 10:02 p.m., and first-arriving firefighters noted light smoke coming from the roof. They helped evacuate the residents and began to attack the fire in the attic.
After the fire was extinguished, investigators determined that the fireworks had ignited a large amount of lint that had been blown from the dryer exhaust and built up on the roof. The fire spread from the lint to the roof covering and underlayment before moving into the attic.
The blaze also spread into the dryer’s exhaust system, which accommodated smaller exhaust ducts from four gas-fired dryers, each of which connected to the larger, single duct that rose from the lower floors of the facility to the mechanical exhaust motor and housing on the roof.
When the investigators removed and examined the ductwork, they found that nearly 50 percent of it was occluded by an accumulation of lint. They also found partially burned lint in the exhaust duct assembly and in the bell housing. Although the roof exhaust fan and the electric motor showed no signs of direct flame involvement, smoke damage was clearly visible. The investigators’ report cited the management’s failure to clean the lint out of the dryer’s exhaust system as a contributing factor to the blaze.
The building and its contents, which together were valued at more than $6.9 million, sustained a combined property loss of $1.5 million. There were no injuries reported.