PVC Scrap Fire Tough to Fight
Photo by Rocky Santoro
A fire in nearly 1 million pounds of polyvinyl chloride scrap stored in a noncombustible building in San Jose, Calif., created a difficult extinguishing problem as the application of water resulted in the formation of a crust over molten PVC.
Hydrochloric acid gas that was a product of the fire made the use of self-contained breathing apparatus mandatory. It also caused damage not only to breathing apparatus metal surfaces and gaskets, but also to metal equipment being manufactured in a nearby building.
At 4:16 p.m. last October 9, the San Jose Fire Department received a telephone report of a fire at 1080 North 11th Street. Communications dispatched Engine 2 (a 1500-gpm pumper), Hose 2 (a 1000-gpm pumper), Hose 5 (a standard hose wagon), Truck 5 and Light Unit 5. The battalion chief of District 1 was also dispatched.
The prevailing wind was from the north at 10 to 15 mph and as fire equipment approached the scene, a large amount of thick, black smoke was coming from the south side of the building.
PVC scrap burning
The structure was a one-story, 50 X 150-foot, galvanized sheet metal building. All support members were steel as was the roof structure. The roof covering was also sheet steel.
An employee informed the captain of Engine 5 that the burning contents were PVC scrap. This scrap had been ground or shredded into pellet size pieces and placed in 4 X 4 X 4-foot bins. These bins would normally be shipped to a plastics manufacturer and the contents recycled. Each bin weighed approximately 1500 pounds. There were nearly 1 million pounds in storage.
The battalion chief, on being informed of this, instructed all fire fighters to don self-contained breathing apparatus and to stay upwind of the smoke as much as possible. During fire operations more than 100 air tanks were used.
The initial attack was made from the north side of the building. Engine 5 connected to a hydrant 75 feet north of the structure and the hose wagon laid three 2 1/2-inch lines to the building. These lines were hand-held and . directed through windows.
These same lines, plus two more later supplied a deluge set and elevating platform. Two preconnected 1 1/2-inch lines were used as a heat shield while the deluge set was positioned. Penetration was made through a garage door type opening after the door had been removed by the truck crew. Penetration of master streams was hampered by a sheet steel interior partition and by part of the roof which had weakened and sagged into a V. The bottom of the V was about 4 feet from the floor. The containers of PVC scrap were made of heavy cardboard, which quickly burned away and allowed the PVC to spill over a wide area. These containers were palletized and stacked two high.
At 4:30 p.m., a call was made for an additional engine and truck. Engine 7 and Truck 1 were dispatched. Engine 7 was used primarily to check for spot fires that may have been started by burning debris carried downwind of the fire. Truck 1 and its light unit were used to assist Truck 5 in opening up the building. Power saws and air chisels were used to cut away sections of the sheet metal siding. This gave hose streams access they could not otherwise gain.
Crust formed on PVC
It was decided to use the elevating platform of Truck 1 with its 1000-gpm nozzle. By positioning the truck so the nozzle could be aimed through the garage door opening, we hoped to flood the fire area. This attempt was fairly successful. Engine 2, which had laid two lines from North 11th and Horning Streets, continued to use hand lines on the fire. Engine 7 at this point dropped a 2 1/2-inch line from Engine 2 to the southeast corner of the building and began an attack from that position. This area was relatively smoke-free by this time.
As some of the heat and smoke dissipated, we found why we were having such difficulty in gaining control of the fire. As the plastic burned, it melted. When this molten mass was hit with water, the surface solidified into a crust 2 or 3 inches thick which protected the burning material below. By forming three-man crews, one hose man with a 1 1/2-inch line and two men to break and remove the crust, we finally were able to extinguish the burning material.
An employee had discovered the fire in its early stage of burning in two of the storage bins. Before he could get a fire extinguisher, the building became charged with smoke.
“The smoke was so dense,” said the employee, “that I couldn’t see my hand in front of my face.”
Smoke rapidly fills building
This meant that a building with a volume of more than 100,000 cubic feet was completely charged in less than two minutes!
Our total time on the scene was over 10 hours. It took nearly three hours to gain control of the blaze and the remainder of the time was used for hard, manual overhaul and extinguishment. At one point, a front-loader tractor was used to remove material from the building. Due to its size and the fact that the roof was down, the loader could reach only a small portion of the building. Other actions taken during the course of operations were as follows:
Businesses downwind were evacuated. Police personnel supervised this and then secured a large area to the south, allowing no nonemergency personnel back in.
A shuttle was set up from Station 20 (our air-oxygen refill base) which assured a constant supply of air tanks. Without this supply of air, fire fighting efforts would have been impossible.
Fire fighters affected
One fire fighter was overcome by the smoke while briefly exposed without an air mask. He was treated at Valley Medical Center and released. Twenty other fire department members complained later of sore throats, headaches, and congestion.
Much of our equipment was damaged by the hydrochloric acid formed during the fire. This damage was in the form of rust on most exposed metal surfaces and deterioration of gaskets and other components of the self-contained masks.
The D. G. Mountz Precision Engineering Company, located in the nearby Hellyer Building, received damage from acid-laden smoke that permeated the building. Mountz manufactures test equipment used in the electronics industry. Nearly all of this equipment sustained rust damage that made it unsuitable for “clean room” use. The company estimated its loss at nearly $200,000.
The cause of this fire has not been determined and is under investigation.