Auto Parts Store Roof Collapse Double LODD 1996

Roof Collapse Chesapeake VA 1996 Double LODD

OVERVIEW

On March 18, 1996, two firefighters were killed in Chesapeake, Virginia when they became trapped by a rapidly spreading fire in an auto parts store and a pre-engineered wood truss roof assembly collapsed on them. The cause of the fire was an electrical short created when a power company truck working in the rear of the building drove away with its boom in an elevated position, accidentally pulling an electrical feed line from the main breaker panel at the rear of the store.

Post-incident investigations indicate that the electrical fault may have sparked multiple points of fire origin throughout the roof structure of the building, due to improperly grounded wiring. At the time of the report issuance, this was exemplified as another incident illustrating the rapid failure of lightweight construction systems when key support components are involved in a fire. The report pointed out the importance of prefire planning and accurate size up by fire companies to determine the risk factors associated with a fire in this type of construction.

Lessons regarding importance of initial company actions, constant re-evaluation of action plans, strong command and coordination of units on the fireground, and recognition of signs of impending structural failure were also reinforced.

Reading through any number of NIOSH, USFA or NFPA reports, similar issues, challenges and operational factors resonate and continue to shape and challenge today’s fire ground operations.

It is without exception that the knowledge and insights being gained by the continuing efforts from the UL and NIST Research Studies coupled with the recommendations, from the NIOSH Fire Fighter Fatality Investigation and Prevention Program (HERE) will provide increased awareness and understanding of buildings, fire dynamics and the effectives of fire within the compartment, building and the manner in which fire departments engage in fire suppression operations.

Today’s fire ground is changing at a very rapid pace as it relates to the continued evolution, transition of engineered structural components and systems (ESS).

Are you prepared, knowledgeable and understand that new strategic and tactical approaches are required?

One of the most significant actions initiated by the Chesapeake Fire Department was the implementation of a Truss Identification Program (TIP).

Take a look at a past posting on CommandSafety.com where we published on an overview a few years ago of truss and engineering component systems across the United States HERE.

City of Chesapeake (VA) Truss ID Program, HERE

The following are excerpts and narrative from the USFA Technical Report Series TR-087 and NIOSH Report 96-17

Aerail Overview on Complex today

 

SUMMARY OF KEY ISSUES

Staffing : The first alarm response provided a small attack force with limited capabilities. The full response brought only 10 personnel.

Size-up : The first arriving company officer was not able to determine the location and extent of the hidden fire.

Pre-fire plan information: This complex required a pre-fire plan due to the complex arrangement, multiple occupancies, mixed construction, lack of fixed protection, limited access and difficult water supply problems. The first-due company did carry a pre-fire plan that showed the layout of the shopping center and the floor plan for the auto parts store, but the prefire plan was not referenced by the crew during the fire.

Delayed response: The first arriving company was on the scene alone for several minutes with only 3 personnel. The back-up companies had long response times. The lack of evidence of a working fire prompted the initial incident commander to return some of the responding units, resulting in even longer response times.

Water supply: The first-in company did not establish a water supply. This required the second engine company to be committed to this task.

Incident command: The battalion chief was faced with a complicated and rapidly changing situation. He was not able to effectively transfer command from the initial officer and direct the operations of widely separated units.

Operational risk management:The officers involved in the initial part of the operation had to make critical risk management decisions with limited information.

Accountability: Accountability for the personnel operating in the hazardous area was not established prior to the structural collapse. As the situation became critical, no one realized that a crew was still inside the building.

Rapid intervention crew: Additional crews did not arrive in time to assist the crew that was in trouble inside the building.

Radio communications: The lack of a clear radio channel for fire ground communications caused serious problems with command and control of the incident, including the failure to maintain communications with the crew inside and the failure to hear their request for assistance.

Lightweight construction: The roof collapsed quickly and with very little warning. This should be anticipated with a lightweight wood truss roof assembly. This hazard was not recognized by the crews on the scene.

BUILDING DESCRIPTIONConstruction and History

The fire occurred in a modern, lightweight construction building that was added to an existing strip mall in 1984. The older mall on exposure side four was separated from the fire building by a masonry fire wall and was constructed with masonry walls and a steel bar-joist roof structure. The exposures on side two consisted of additional stores that were similar in construction to the auto parts store. There were no exposures on sides one and three.

The auto parts store was constructed with two masonry exterior walls and two wood frame exterior walls, with a lightweight wood truss roof assembly. It was approximately 120 feet deep and 50 feet wide, providing about 6,000 square feet of open display and storage space. The roof assembly was a pre-engineered lightweight wood truss assembled from 2 x 6 top and bottom chords, with 2 x 4 web members held together with metal gusset plates.

  • There were no interior bearing walls or supports for the roof structure. At one end, the trusses were supported by a wood plate that was bolted to a metal beam.
  • The other end rested on top of the concrete block wall. Each truss was separated by 24 inches and they were covered with 1/2 inch CDX plywood sheathing under a two-ply rubber membrane.
  • A drywall ceiling was attached to the underside of the trusses, creating a truss void space (truss loft) 24 to 36 inches above the ceiling.
  • A sheet rock divider was located in the middle of the truss void as a draft stop. The roof had a slight pitch.
  • Three air handling units were on the roof of the building, with an estimated combined weight of 3,000 pounds. It is not known when these units were installed and they may have represented an unanticipated dead load on the roof assembly.
  • There was no indication that the trusses had been reinforced to support the extra weight of these units.
  • The original truss roof structure collapsed during the construction of the building, injuring three workers.
  • Most of the trusses were damaged and had to be replaced at the time. The fire building was occupied by Advance Auto Parts, a chain distributor of automobile part and lubricants. The store was designed with an open retail area containing display racks for goods.
  • A long counter ran from front to back behind which was shelving for additional auto parts. Waste oil and batteries were kept in a rear storage area separated from the front of the store by a drywall wall.
  • The southwest corner of the building contained employee restrooms which had a small water heater located in the ceiling space just above them. The main entrance to the store was through two large glass doors at the front of the building. A delivery and service entrance was located in the rear and a 40 foot trailer was parked behind the building and used for additional storage.

THE FIRE

At approximately 11:00 a.m. on March 18, 1996, a power company employee set up a service truck at the rear of the Indian River Shopping Center in Chesapeake, Virginia. The worker was going to disconnect the electrical power to a customer who had not paid an electrical bill. The customer, a cocktail lounge and bar, was located adjacent to Advance Auto Parts. In preparing to disconnect service, the power company worker elevated the articulating boom on his truck to roof level. Faced with the immediate loss of power, an employee of the lounge paid the electrical bill while the power company employee was beginning work, and went to the back of the store to show the receipt.

A stamped receipt indicates the bill was paid at 11:16 a.m. at a supermarket also located in the shopping center. The power company employee, working from the bucket of the articulating boom, lowered the boom and verified the receipt. Although the bucket had been lowered, the hinged elbow of the articulating boom remained elevated. The employee then radioed his supervisor from the cab of his truck, and received instructions not to disconnect power.

The power company employee then attempted to drive the service truck away, forgetting to secure the boom, which snagged on a power line feeding the meter at the rear of the Advance Auto Parts Store. This caused a phase-to-phase and phase-to-ground arcing fault at the store’s electrical meter, starting the fire. The power company employee immediately stopped, exited his truck, and cut the remaining power connections to the meter at the rear of Advance Auto Parts.

Initial Actions Prior to Calling 911

After cutting the power line to the building, the power company employee removed the meter, noticed smoke coming from the meter base, notified his office and requested that another power company crew and a supervisor come and assist him.

  • An employee of the Advance Auto Parts Store came to the rear of the building and met the power company employee, telling him that the store had lost electrical power and that a fire was being extinguished inside the building.
  • Another Advance Auto Parts employee discharged a dry chemical fire extinguisher on the spot fire that had started near the hot water heater above the employee restrooms.
  • All believed the fire had been extinguished at this time.
  • At 11:29 a.m., the Chesapeake Fire and Police Emergency Operations Center received a 911 call from Advance Auto Parts reporting a problem with the fuse box in the store.
  • The Chesapeake Fire Department was dispatched to a report of a fuse box sparking at 4345 Indian River Road at the Advance Auto Parts store.

Emergency Response

  • Initial response consisted of two engines, a ladder company, and a battalion chief, for a total of 10 personnel.
  • Engine 3 was the first due arriving company, responding from quarters. Engine 1 and Ladder 2 also responded.
  • Battalion 1 was dispatched as the command officer, but requested that Battalion 2 cover the assignment, since he was out of position.
  • Battalion 2 acknowledged the request, and he responded with the first alarm companies.
  • Engine 3’s crew consisted of three personnel: a driver/pump operator; Firefighter- Specialist John Hudgins, serving as Acting Lieutenant for the shift; and Firefighter- Specialist Frank Young, detailed to the station for the day, was riding in the jump seat. Engine 3 was responding in a reserve engine that had a 500 gallon water tank.

 

Initial Size-Up and Company Actions

At approximately 11:35 a.m., about five and a half minutes after dispatch, Engine 3 arrived on the scene at the front of the strip mall.

  • Hudgins reported “a single-story commercial structure, nothing showing from the front. Engine 3 is in command.”
  • Engine 3 took a position in front of the Advance Auto Parts Store. Hudgins and Young entered the structure from the front of the building to investigate.
  • Conditions were clear in the store, and there was no visible smoke or flames showing. They discovered light smoke near the electrical panel in the rear of the building, and radioed to Battalion 2 that they had a fire and were checking for extension.
  • Acting Lieutenant Hudgins then radioed for Engine 3’s driver to reposition the apparatus to the rear of the building.
  • Hudgins then radioed to Battalion 2, who had not yet arrived on the scene, that Engine 3 and Ladder 2 could handle the incident. Battalion 2 and Engine 1, the second due engine company, both went in service.

Engine 3 Reports They Are Trapped, Roof Collapses

At approximately 11:49 a.m., almost 20 minutes after the initial dispatch time, Hudgins radioed that he and Young could not get out of the building. Battalion 2 radioed back that he could not understand their transmission. Hudgins then radioed that they needed someone to come to the front of the building and get them out. Again unable to understand their transmission, Battalion 2 radioed for any unit on the fireground to advise him if they heard the message that was transmitted.

  • Engine 4 responded that they were unable to copy the transmission.
  • Engine 14 then marked on the scene and was instructed by Battalion 2 to lay a supply line to the front of the building. Battalion 1, enroute to the fire on the second alarm, radioed to Battalion 2 that it sounded like someone was trapped inside.
  • Battalion 3, also enroute, radioed that he would be on the scene momentarily and would assist.

At this time, Ladder 2’s crew was setting the outriggers and preparing to elevate their aerial ladder for defensive operations.

  • In the short time it took to accomplish the stabilization of the ladder truck, the front of the store became fully involved, the building contents ignited, and the roof collapsed.
  • Due to the radiant heat, Ladder 2 was forced to retract their outriggers and reposition to a safer defensive position on side one of the structure, and set up the aerial again.
  • Ladder 2’s crew did not hear Engine 3’s transmission that they were trapped.
  • Simultaneously, Engine 1 ran out of supply line about 200 feet short of the hydrant. Engine 2, responding on the second alarm, picked up the hydrant that Engine 1 was attempting to reach and laid a supply line to side one.
  • The driver of Engine 1 attempted to contact his officer by radio to advise that he could not reach the hydrant, but could not get through due to heavy radio traffic.
  • He parked the engine in the roadway, donned his SCBA, and went to the rear of the building to report to his Captain and rejoin his crew.
  • Battalion 3 arrived on side one about this time and radioed for all companies to switch to channel two, an alternate fireground tactical frequency.

Driven by the northerly wind and the draft created by the burning contents of the structure, the fire at the rear had grown in such intensity that personnel were forced to move Engine 3. Assisted by employees of the power company, Engine 3 was moved back away from the rear of the building. At 11:55 a.m., about 26 minutes after dispatch, the Captain of Engine 1, with his crew at the rear of the building, confirmed to Battalion 2 that “I got men on the inside from Engine 3, and the lines have been burned. I do not know their status, and we still have no water to go in after them.”

Battalion 3 met with Battalion 2 and discussed that they may have lost a crew inside. Battalion 3 assumed command and Battalion 2 went to the rear of the building to coordinate rescue efforts. There, Battalion 2 met with the Captain from Engine 1.

By this time, the building was fully involved and no rescue efforts could be mounted until the fire was knocked down. Officers at the front and the rear attempted to conduct a personnel accountability report (PAR) to determine who was missing and where they might be located.

  • An engine company responding on mutual aid from the Virginia Beach Fire Department was flagged down, connected to Engine 1’s supply line, and completed the water supply to a hydrant behind the shopping center within the City of Virginia Beach. Engine 3 was forced to move back once again, and the supply line was disconnected from Engine 3 and used to supply water to Engine 4, a telesquirt that was positioned for defensive operations at the rear.

Extinguishment and Body Recovery

The fire spread to the attic of the exposures on side two and was held in check by the fire wall on side four of the building. The fire was brought under control as the contents of the auto parts store burned off and several aerial streams were put into operation. After the fire was extinguished, a search for the missing firefighters was initiated. After the bodies of the firefighters were located, they were removed from the fire building by members of the Virginia Beach Fire Department, and transferred by members of the Chesapeake Fire Department to medic units.

The body recovery was supervised by the Chesapeake Fire Department Fire Marshal’s Office and documented. An investigation was immediately started by the Chesapeake Fire Department Fire Marshal.

ANALYSIS

Fire Cause and Flame Spread

  • The fire was caused by the electrical short created when the power company truck struck the power line to the building. Investigation by the City of Chesapeake Electrical Inspector after the fire revealed that the meter contained wiring that appeared to have been tampered with and did not comply with the electrical code.
  • Several connections at the meter had been double-lugged, connecting multiple wires to single terminals. Additional investigation by Virginia Power revealed that the building may have been improperly grounded, leading to numerous hot connections when the short circuit occurred. The main fuse did not trip at the breaker panel and the wiring on all three air handling units had been fused. This probably resulted in the ignition of multiple spot fires in the truss loft above the store.
  • It appears that the fires in the truss loft were still relatively minor when Engine 3 arrived, but the fire spread rapidly throughout the space due to the light wood construction.
  • The wind drawn from the open doors at the front of the building also promoted rapid fire growth. This would have created a tremendous hidden fire in the wood truss loft area despite clear conditions inside the structure.
  • Reports of heavy smoke and fire conditions on the roof at the same time Engine 3’s crew was calling for pike poles and personnel to come inside are indications towards this scenario.
  • The interior of the auto parts store contained racks of auto parts and supplies, including oil, lubricants, rubber, and plastic parts. The contents were packed closely together and stored in tall racks near the ceiling.
  • Once the fire had broken through the ceiling in the rear of the building, these contents would have quickly reached their ignition temperatures, creating flashover conditions in the rear of the store as the fire progressed, trapping the firefighters and forcing them to seek an exit at the front of the store.

Roof Collapse

  • The collapse of the pre-engineered truss roof occurred approximately 21 minutes after the time of dispatch, and within 35 minutes of the initial accident, that caused the electrical short.
  • The structure appears to have collapsed within 10 to 12 minutes after the truss space became heavily involved.
  • The collapse of similar truss assemblies under fire conditions within this time period has been well documented.
  • Post-incident investigations indicate that this truss assembly may have been weakened by deficiencies in the connection of the trusses to the beam on the east side of the building.
  • Also, the dead load of the three air conditioning units may have contributed to the rapid failure of the roof.
  • Reports from firefighters on the scene indicate that a partial failure of the truss assembly may have occurred in the rear of the building, followed shortly by the failure of the entire roof assembly.
  • It is possible that the crew of Engine 3 was trapped by the partial collapse of the roof in the rear, or by the collapse of racks containing auto parts in the building, or by the rapid spread of the fire and smoke which had broken through the ceiling.
  • It is also possible that a combination of these events occurred simultaneously. The failure of the entire roof assembly and complete involvement of the interior of the building with fire took place within one minute after the firefighters radioed for help, before any reaction to assist them could take place.

Fire Operations

 

Initial Response - The first alarm assignment was overwhelmed by the situation, the circumstances, and the unusual sequence of events that occurred at this incident. It is evident that a larger force would have been needed to initiate an effective offensive or defensive operation for a working fire in a 6,000 square foot commercial occupancy, with attached exposures on two sides, with or without the unusual complications.

  • The response of two engine companies, one ladder company and a battalion chief, provided a total of 25 only 10 personnel on the initial assignment.
  • The individual companies, which responded with three person crews, had limited capabilities to perform tasks independently.
  • This incident generated only a single call to 9-1-1 reporting an electrical problem.

 

LESSONS LEARNED AND REINFORCED

1. RISK ASSESSMENT is the primary responsibility of the incident commander.

This incident presented a very high risk to the firefighters who were attempting to make an interior attack. However, the risk factors were not recognized and the interior crew was not directed to abandon the building. Risk assessment should be a continual process, particularly when a situation is changing very quickly.

2. ACCOUNTABILITY is an essential function of the Incident Command System.

The location and operation of the initial attack crew was not tracked according to the incident command system that was in effect at the time of the fire. The system must keep track of the location, function, status, and assignment of every individual unit or company operating at the scene of an emergency incident. In order to be effective, the accountability process must be routinely initiated at the beginning of every incident and updated as the incident progresses and units are reassigned to different tasks.

3. TACTICAL RADIO CHANNELS are essential for firefighter safety.

The fireground operations were conducted on the same radio channel as the routine dispatch and transfer of additional units, hampering the fireground communications during the important early stages of the incident. Designated radio channels should be set aside specifically for communications between the incident commander and the units operating at the scene of an incident. The exchange of information, orders, instructions, warnings, and progress reports is essential to support safe and effective operations. Tactical channels should be assigned early and routinely to avoid the confusion that occurs when units that are already working are directed to switch to a different radio channel.

4. FIRE OPERATIONS must be limited to those functions that can be performed safely with the number of personnel that are available at the scene of an incident.

The initial response to this incident did not provide enough resources to safely initiate an effective interior attack for the situation that was encountered. The first arriving company initiated interior operations that could not be adequately performed or supported with the limited number of personnel at the scene or responding. The delayed arrival of back-up companies increased the risk exposure of the first due company. The situation called for a more conservative initial attack plan and/or an early retreat when the magnitude of the fire became evident.

5. WATER SUPPLY is a critical component of a safe and successful operation.

The failed attempt to establish an adequate and reliable water supply for the interior attack was a critical problem at this incident. This task occupied the second due engine company which was needed to provide either a back-up hose line to support the interior attack or a rapid intervention crew.

6. LIGHTWEIGHT WOOD TRUSS CONSTRUCTION is prone to rapid failure under fire conditions.

If the construction of the building had been known or recognized, the early failure of the roof structure should have been anticipated and the interior crew should have been withdrawn. This requires pre-fire planning to identify high risk properties and a reliable system to label the building or to inform the responding units of the risk factors of the building. It is usually difficult or impossible to make this determination when the building is burning.

Aerial View of the Current Auto Parts Store 2010

 

USFA Technical Report Series Incident Report: Tr-087 NFPA 1996 Report Summary Sheet: NFPAChesapeake

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