L. P. Gas Pipe Rupture Creates Disaster Peril in Los Angeles
Swift Precautionary Moves By Fire Department Prevents Ignition of Gas
¢LAFD Photos by Cecil Lynch
A VIOLENT RUPTURE in a squatty pit holding controls of an underground tank loaded with LPG (liquefied petroleum gas) recently created a disaster potential in the heart of Los Angeles’ crowded downtown industrial district.
The break in the LPG system spewed a geyser of raw liquefied petroleum gas into the air over the Carnation Creamery at 1634 North Main Street. The gas almost immediately vaporized into a gigantic cloud which, if ignited, could have touched off an explosion rivaling in proportions the famous Texas City disaster.
Courageous action displayed
The story of how the Los Angeles Fire Department met this emergency and through sheer courage averted a catastrophe is of significant interest to the fire service and moreover provides a basis for a review of the entire problem of LPG fire safety.
The once-in-a-million-years chain of circumstances leading up to this problem, perhaps unparalleled in the entire history of this nation’s fire service, started at 6 o’clock in the morning.
A truck and trailer loaded with a 60-40 blend of propane and butane pulled into the yard of the creamery. The driver unloaded the contents of his trailer into the 5400 gallon tank and then towed the trailer out to the street where he uncoupled it. Either through carelessness, haste or oversight, he neglected to chock the truck’s wheels when he began unloading the truck compartment.
At 9:15 a.m., when the unloading was completed, the driver climbed into the cab and reached for the rod to take the pump mechanism out of gear. Instead, he accidentally hit the road gear lever and the truck, still connected to the fill pipe, bolted forward five feet and stalled.
Although the rubber hose stretched, it did not break. But the fill pipe did and the liquid LPG under pressure spurted from the 2-inch break. An automatic internal valve in the pit should have closed, but the break in the fill pipe jammed the valve open.
The driver spread the alarm and the dairy supervisor pulled the master switch. Ironically, an ice cream truck freezer motor was operating just a few feet from the pit’s mouth, but fortunately the supervisor’s quick work shut off this potential ignition point.
While the supervisor notified the Westlake Signal Office of the Los Angeles Fire Department, another dairy worker saw the the liquid LPG streaming across the yard and out into the street. The inflammable river headed for the open furnaces and drop forges of a foundry directly across the street. The dairy worker ran to the foundry and told workers there to shut down the plant. Luckily, the liquefied gas ran off into a storm sewer drain before it reached the foundry.
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When Chief Homer Hall of Battalion 2 arrived, he radioed for a second alarm assignment as he saw a sizable vapor cloud boiling up from the spouting gas. First alarm apparatus immediately laid lines to protect exposures when the gas blew. There seemed little doubt at that time that the vapor cloud would find a source of ignition.
Other firemen raced through nearby buildings, including a boiler factory, a winery and homes, helping workers shut off all potential sources of ignition. Police and firemen evacuated 300 people from the area and plant workers were sent home. Countless gas pilot lights were turned off, fork lift truck motors in a warehouse were stopped and every possible precaution was taken. Yet a mere spark, perhaps from an arcing trolley wire or the careless scuff of a nail sticking out of the heel of a shoe, could have touched off a disaster.
So cautious were firemen that fire apparatus was pushed by hand to locations on the leeward side of the enormous cloud bulging ever larger over the area.
Captains Leo Najarian and Don Wilson of the Fire Prevention Bureau estimated the vapor cloud as equal in explosive power to 105 tons of dynamite. The large loss which could have occurred is indicated by figures prepared by them:
“At normal atmospheric pressure, the volume of gas released would occupy roughly 180,000 cubic feet, enough to cover a 300′ by 600′ city block to a depth of one foot.
“Mixed with the proper proportions of air, 8,250,000 cubic feet of flammable and explosive vapor would be formed, enough to cover the city block to a depth of some 40 feet.”
While fog streams were used to create a turbulence in the air, which aided in dissipating the vapors, the L.A.F.D.’s liquefied petroleum expert, Inspector John W. Willis, volunteered to enter the vapor cloud and attempt to shut off the jammed valve.
Fellow firemen covered Inspector Willis with a protective umbrella of fog as he approached the 42-inch wide pit. A refrigerating action accompanying the vaporization had formed a mound of slush and ice over it. Inspector Willis, who was familiar with the 4-foot-deep pit’s layout, inasmuch as he supervised its construction two years before, unsuccessfully probed in the bubbling mass with a pike pole for the jammed valve.
When Inspector Willis groped in the pit for the valve, his arm was instantly seared by the frigid cold. The temperature of the water, LPG, slush and ice was estimated at 46 degrees below zero in the pit. Yet, one spark could have transformed that frosty mess into 3600 degrees of white hot fury!
Only after considerable difficulty, and with extreme peril to himself, was Inspector Willis able to effect a shutoff. By the time he got the valve shut, the 5400 gallons of LPG were virtually dissipated. He finally reached the valve by crawling on his stomach to the lip of the pit and with his face a scant few inches from the bubbling mass reached down inside and felt for the valve.
Inspector Willis had decided against using a mask while working inside the zone of penetrating gas, and just as he turned off the valve, he lost consciousness. He was quickly revived in the dairy yard.
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A special training bulletin prepared bv the Fire Prevention Bureau of the Los Angeles Fire Department was made available to readers of Fire Engineering. The concise report admirably sums up the qualities of LPG and emergency procedures to be followed:
“LPG normally is stored in a vessel or tank under sufficient pressure to remain a liquid. The gas is heavier than air and if not dissipated may flow like water to lower levels such as basements, pits and storm drains. This condition could create a hazard which might continue to exist after the apparent emergency is past.
“LPG has an ignition temperature above 800 degrees Fahrenheit and a flash point of approximately —75 degrees Fahrenheit. The flammable or explosive range of the vapor is approximately 2 to 9 per cent by volume with air.
“The gas is transported through cities in large tank trucks and is stored in large and small tanks, both above and below ground for standby and reserve fuel and heating systems. It is also used in torches for cutting metals, as a substitute for natural gas in heating devices and appliances and as a motor fuel instead of gasoline.”
The LAFD Fire Prevention Bureau also discussed emergency procedures to be followed:
“Because of the inherent hazard …and the increased use of liquefied petroleum gas, re-emphasis of precautions and proper procedures to be taken at the scene af leaks and spills should be made. These recommendations apply to conditions where ignition has not taken place and where substantial quantities are involved.
“There is no sure method of determining the safe limits of the vapor area without proper testing equipment; however, all areas where its distinctive odor is present should be considered unsafe.
“Lines should immediately be laid and numerous fog or spray streams provided.
“Prevent all vehicles from moving through the vapor area under their own power. This includes apparatus and police cars.
“Report to the signal (or alarm) office giving all particulars of the incident and request testing equipment, explosimeters, the fire prevention engineer or deputy on call, adequate police aid to control vehicular traffic and response from utilities affected.
“Eliminate all dangerous sources of ignition nearby as soon as possible and keep a check of adjoining areas, as the explosive mixture may travel a considerable distance.
“Evacuate all persons to safe location.
“Enter the vapor area only if a shutoff can be effected and then only under the protection of fog or spray streams. Remember these vapors are not soluble in water, but fog and spray streams create air currents which help dissipate the vapor.
“Self-contained breathing apparatus or hose masks must be used when rescuing persons from basements, manholes or pits.”
Chief officers of the Los Angeles Fire Department took notice of the courage of the men whose teamwork averted disaster, and especially that of Inspector Willis.
An official commendation of Inspector Willis said in part: “He certainly made a valiant effort and in the face of imminent danger of ignition of the gas. … The emergency lasted about three hours and Inspector Willis worked, thoroughly soaked and constantly exposed to great personal jeopardy during the entire period.
“Surely his actions were in accord with the highest traditions of the fire service—protection of life and property with utter disregard for personal safety and exceeded, I believe, the call of duty under the circumstances.”