FRANCIS BRANNIGAN
Firehouse.Com Contributor
Firefighter Dies In Abandoned Mini-Storage Building. This tragedy occurred several years ago but the lessons are still pertinent.
The Fire
On August 3, 1994 a Louisville firefighter plunged through a lightweight truss roof of a one-story concrete block, self-service storage building (mini-warehouse) and died. The Louisville Fire Department prepared a comprehensive investigative report and we are indebted to Fire Chief John B. Corso for providing a copy, and giving permission to use the information for the benefit of the fire service.
The alarm office received several calls about this fire at 0347. This certainly indicates a working fire and at this early morning hour should cause all to think, "This fire has probably been burning for some time, but has just now "shown up". Heavy smoke but not much heat was reported on arrival at an abandoned self-storage warehouse.
The roof was plywood with fiberglass composite shingles supported on typical lightweight triangular trusses 24" on center. The ventilation crew had opened the roof. Ventilation relieves smoke and heat but it accelerates the fire. The roof was not spongy.
This is characteristic of trusses until they collapse without warning. (When the US Forest Products Laboratory studied how to make safe trusses it was suggested that trusses might be designed so that some part would fail causing the truss to sag and thus warn the firefighters!!) The warning is in knowing the construction of the roof.
The roof collapsed at about 0400 on the opposite side of the roof from the vent hole. Heavy fire erupted from the hole. One firefighter fell through the hole.
Unfortunately the layout of the building was not typical. Usually the storage bins are back to back with overhead doors from the outside. However in some cases there is an interior corridor with the only openings to the bins from the interior corridor.
The firefighter fell into the corridor. Two bin doors were open into the corridor blocking the view of the fallen firefighter. It took 19 minutes to remove the firefighter who was transported to the hospital where he died.
When a successful vent is made, the air supply to the fire is increased. (537 BTU are generated for each cubic foot of oxygen consumed by the fire. Not "delivered to, as I have previously written.) The structure can be deteriorating rapidly. It can be very dangerous to remain on the roof to admire your handiwork or to make another cut.
It was not a factor in this case but firefighters working on a roof should have two separated means of egress. No roof was ever designed to be a firefighter's working platform. In my opinion we must abandon the concept that every dump must be saved.
Possibly Misleading Data
The report contains a sections entitled:
- 3D Physical Properties under Fire Load
- 3E Cause of Failure
- 3F Summary
In the summary, the author reaches the conclusion that the critical temperature in the wood trusses was reached 18.75 minutes before the recorded collapse time. Based on numerous questions asked in seminars, there is a widespread belief in the fire service that firefighters can remain safely in or on a structure on fire for 20 minutes.
My concern is that the 18.75 minutes, (which I consider an invalid conclusion, since we cannot know when the clock started) is close enough to 20 minutes to give credence to the false and dangerous mythical "20 minute rule".
The author discusses the "Standard Time Temperature Curve", the curve specified for tests under ASTM E 119, without pointing out that it is the curve specified for comparative tests and has no relationship to any specific fire.
In fact in 1980, the National Bureau of Standards (now NIST) published "Fire Development in Residential Basement Rooms" (NBSIR 80-2120). In those tests the temperature peaked at over 1800 degrees Fahrenheit in ten minutes. The fire report indicates that there was a high fire load in the fire building, probably much higher than in the NBS tests which represented a typical basement recreation room, or a typical living room.
Conclusions of the (NBS) report are noteworthy. "The rate of development and intensity of real fires involving the burning of typical furniture and interior linings in a room during the first 20 minutes, may be significantly greater than those defined by the ASTM E119 standard time-temperature curve"
A possible change in the standard fire threw the industry into a panic. They protested to the President Reagan administration, no friend of any government regulation, and for five years fire research at NBS was zero funded.
Only strong Congressional efforts backed by most of the fire protection community preserved it. All our fire resistance ratings are based on a standard shown to be too weak. It is simply not valid to use the Standard Time Temperature curve as a constant in an analysis of any specific fire.
We should be aware of deficiencies, misunderstandings and possible deliberate deceit in the whole matter of fire resistance ratings, and dangers of the "defend in place" concept in combustible buildings
The ASTM test is conducted usually with an evenly distributed static load of 30/40 pounds per square foot. Three firefighters on the roof represent a dynamic load of several hundred pounds over a small area. In addition, the impact load of moving around, cutting the roof, even with a chain saw, and removing the covering, is severe though never determined.
I have observed many cases where trusses do not have the required depth of penetration. Mishandling of trusses on the construction site loosens gusset plates. They are also loosened by hammering by trades persons installing equipment. Such trusses would fail even earlier than perfectly built trusses in mint condition.
Firefighters would be well advised to place more credence in the tests conducted by B.C. John Mittendorf (Ret) of the Los Angeles City Fire Dept. which showed collapse in 3-4 minutes. The fires were not standard, but typical. There was no superimposed load on the structure, a bias in favor of the structure. See BCFS3 p.526-548
Recommended SOP
Firefighters should not be under or on any truss involved in fire. The thermal imager, the firefighter's radar, should be used by a trained operator to determine the heat situation (For further information see Building Construction for the Fire Service, 3ED Chapter 12, Trusses)
Note that some years ago, the Fort Worth, Texas Fire Department had a multiple alarm fire in an all-steel storage building with an interior corridor to serve the rear storage units rather than the typical back to back storage. They were unaware of the interior corridor arrangement since the building had not been preplanned and 126 units were destroyed.
Due to the tremendous heat and the danger of flashover from unknown contents, it is my opinion that it is an unjustifiable risk to deploy units down the corridor to reach an advanced interior fire. There is a severe potential for entrapment.
The better method might be to estimate how far away on each side of the fire the building should be literally cut off to stop the spread. In the Ft. Worth fire, they were literally playing catch-up. It will be necessary to sacrifice some of such an unmanageable building to save the rest. Keep in touch with the building department to determine if such a design is planned for your area. Your preplanning should stress firefighter safety first last and foremost.
A Personal Note
Maurine, my beloved wife of 58 years, (who had picked me out when she was 17) has been stricken with an incurable malady. She has been my fire service associate in uncounted ways since our days as WWII Naval Officers. If you feel that our efforts have been worth while you might want to let her know at Fbrannigan@aol.com.
Sixty Years, A Unique Career
On October 13, 1942, my 24th birthday, your columnist then a second class petty officer in the Navy Supply Corps with additional duty with the base fire department, was commissioned an Ensign USNR in the Panama Canal Zone and was assigned to a number of serious fire protection duties including fire ground command.
How did a department store finance executive, a red hot FDNY buff and student of fire protection come to be named many years later as one of the 20 persons who most influenced the Fire Service in the 20th Century, by Fire Chief Magazine?
Email. Ask for "Sixty Years". No cost, but you must include a name and fire protection affiliation. "Imaginative" Email addresses will get a reply of "who are you". I am not assembling a mailing list but just as at a face to face meeting or phone call it is customary to identify yourself.
THE BUILDING IS YOUR ENEMY. KNOW YOUR ENEMY
Related:
About the Author - Frank Brannigan
In his 60 year career, which began as a Navy Firefighting Officer in WWII, Frank has "been there, done that" Since 1966,
he has concentrated on firefighter safety in the deadly environment of a building fire.
His general theme will be, as always, "THE BUILDING IS YOUR ENEMY KNOW YOUR ENEMY. KNOW YOUR ENEMY!"
Frank Brannigan has received many honors for his efforts to save firefighters lives. His 667 page book
"Building
Construction For The Fire Service", Third Edition is available. Or you can contact Frank directly
as he offers our readers an autographed copy.
Frank says it makes an excellent present for a firefighting friend, loved one, or newly promoted officer.
Send requests to:
Frank Brannigan
2041 Daylily Rd.
Port Republic, MD, 20676-2646
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