Article

Revamping Duesseldorf

The following article appeared in NFPA Journal Online.  © 2002 NFPA Journal  Reprinted with permission.

In 1996, a catastrophic fire at Dusseldorf International Airport in Germany killed 17 people and injured 87 others. When the new terminal opened last summer, significant changes, prompted by that fire, had been made?  Ed Comeau traveled back to Germany to find out.

On April 11, 1996, a catastrophic fire broke out at the Duesseldorf, Germany airport terminal.  This fire claimed the lives of 17 people, and is the only fire in an airport terminal that claimed civilian lives, according to research done by the NFPA.

The NFPA sent Chief Fire Investigator Ed Comeau to Düsseldorf to document this tragic fire.  At the same time, the British Airport Authority (BAA) dispatched a team of investigators, which included Divisional Officer David Whittington.  Both the NFPA and BAA published reports based on the information that was available at the time.  This article is going to look at some of the information that has emerged following the publication of these reports, as well as changes that have taken place at Düsseldorf Airport.  Both Comeau and Whittington traveled to Düsseldorf Airport and met with several officials in compiling this article.

The Fire

According to a report published by the Independent Expert Committee for the Investigation of the Düsseldorf Airport Fire on 11 April 1996, the fire was started by welding operations.  A welder was working on a roadway expansion joint that was located over the ground floor void space.  The sparks generated by the welding fell into the open joint and came into contact with rubber-like sheets that had been installed to divert water.  According to tests conducted by the Committee, these sheets were classified as “normally flammable,” and it was theorized that they were the material that was first ignited.

Within the void space below the area where the welding was occurring was combustible thermal insulation that was attached to the underside of the concrete deck.  This insulation, which measured 60 mm (2.4 inches) thick, was composed of polystyrene rigid foam.  The Committee believes that the burning rubber-like sheets caused the polystyrene foam boards to melt and then ignite, providing further fuel for the fire.

Because there was no smoke detection in the void space, nor below it in the occupied space, the fire was not detected until it was well developed.  The first alarm came from a taxi driver at 15:31 hours (3:31 p.m.) who observed sparks falling from the ceiling.  This person notified the airport fire brigade, who dispatched two members to investigate.  When they arrive two minutes later, no smoke was observed on the ground floor.

However, on the first floor, some people had observed smoke on this level.  It was assumed that the smoke had migrated up a stairwell to this floor.

After investigating the incident for approximately 15 minutes, the two fire fighters who had originally been dispatched requested additional resources.  Because of the size of the fire and the large area involved in the fire, fire fighting operations were difficult, and the fire was not brought under control until approximately 19:20 hours (7:20 p.m.).

At the time of the fire there were approximately 2,000 people in the building.  Eighty-seven were injured, two seriously, and seventeen people were killed by smoke inhalation.

Seven people were killed in the Air France lounge that was located two levels above the fire and on the opposite side of the terminal building, and one person was killed on the stairway leading to the lounge.  Another seven people were killed in elevators that opened into the fire area.  One person was found dead in a lavatory.

According to the Committee’s report, there was a total of 24,000 kg (53,000 pounds) of combustible fuel.  Approximately 47%, or 11,400 kg (25,100 pounds) of this was comprised of polystyrene, while 24% (5,900 kg (13,000 pounds)) was PVC cable insulation.

The committee’s report addressed how significant a factor the PVC cable insulation was in the spread of the fire. 

“It is difficult to determine in retrospect how the cables contributed to the spread of the fire – whether is would have spread to a similar extent without the supporting combustion of the PS rigid foam, or whether a local initial fire would have ceased due to the combustion properties of PVC.  However, it can surely be stated that even common cables ‘containing no halogen and with a more favourable reaction to fire’ would have been burnt completely due to the combustion of the PS rigid foam.  The application of fire retardants would not have resulted in an essentially better reaction to the terminal fire on April 11^th, 1996.”

According to Dr. Adrian Beard, who worked on the committee, 11 people were charged following the fire.  They included the welder, airport building officers, and staff from the airport and Düsseldorf fire brigades.

Findings of the government study

There were several significant contributing factors to the fatalities identified in the committee’s and the official NFPA fire investigation report.

• In the Air France lounge, both exits from the lounge discharged into the same air space, which was contaminated by the smoke.  Furthermore, the lounge’s windows were not exterior windows, but were separated from the exterior windows by a space of 70 cm (28 inches).  Because of this, these windows could not have successfully been used to escape from the lounge, where seven people were killed.

• The seven people that were killed in two different elevators died because the elevators opened on the fire floor.  Because of the density of the smoke, the doors would not close, nor were the occupants able to see any of the exits in the area.  Even though they were able to make emergency calls to the technical control center, advising them of their plight, this information was not passed on to the fire department quickly enough for them to be rescued.

Other factors identified in the NFPA Fire Investigations report that contributed to the severity of the incident included:

• Improper voice evacuation instructions were given during the initial stages of evacuation, delaying movement of people out of the building.

• Delayed fire department response to the fire

• Use of significant amounts of combustible material in an unprotected void space

• Lack of coordination between the airport fire brigade and the municipal fire brigade

• Communications difficulties among fire fighting units

Changes that have occurred

Given the magnitude of the tragedy in terms of life loss and property damage, the airport authority undertook efforts to ensure that such an incident would not occur again.  A number of changes were made in the design of the building, its systems, staffing, operating procedures and training operations.  These include:

• Installation of sprinkler systems throughout the terminal building.

• Dramatic upgrade of the fire alarm system.

• Staffing of the airport and municipal fire brigades

• The creation of a fire prevention division within the airport

• Development of a comprehensive emergency response plan.

In 1997, a fire prevention division comprised of four fire protection engineers was established, including Stefan Bunthoff, head of Fire Prevention. 

According to Bunthoff, the are four principles that are part of the fire safety strategy employed at the Düsseldorf Airport.  They include:

• Avoiding the occurrence of fire

• Preventing the spread of fire and smoke

• Rescuing people and animals

• The performance of effective fire fighting.

Building Design

Because the fire originated in a combustible void space that was hidden from view, the designers wanted to allay any fears that the traveling public may have about this type of construction.  For that reason, according to Bunthoff, the new design incorporates a completely open ceiling plan, with all of the structural elements and utilities exposed to view.

The use of the materials used in the construction of the building and its fixtures is closely regulated, according to Bunthoff.  They attempt to minimize the fire load of fixtures such as counters, which are often made of metal instead of combustible materials.  Upholstered furniture located in the concourse, must been the requirements of DIN-EN standard 1021.  Insulation material must also meet a DIN standard for combustibility.

Compartmentalization is used throughout the terminal to limit the spread of any toxic smoke or fire.  In the 1996 incident, both were able to spread far beyond the original area of origin, killing people that were located several floors above the fire.  To avoid this happening again, the current terminal is divided into fire and smoke sectors.  This is accomplished by mechanisms such as doors that will automatically close, subdividing areas into these compartments.

Within the concourse are a number of shops that could have a large combustible fuel load because of their inventory.  Some of these shops are located in the middle of the concourse, away from the perimeter walls and are essentially “stand-alone” units.  A concept called a “box cap” system is employed in an effort to provide a level of protection within these units.

Each unit is equipped with a fire sprinkler system at the roof level.  In addition, each unit also has a smoke extraction system that will discharge any smoke logged air to the exterior of the building.  The upper 60 to 70 cm (24 to 28 inches) of the store is equipped with a “cap” that will serve to contain the smoke-filled air and also help to concentrate the heat, allowing for an earlier activation of the sprinkler system than may otherwise be possible.  The doors to the units are security grills, which allow for air to enter into the unit even if it is closed.

Fire Alarm System

The current fire alarm system is comprised of the following elements:

• 3,300 smoke detectors

• 180 manual pull stations

• 50 air aspirating smoke detectors

• 20 linear infrared (IR) smoke detectors

• 2,800 loudspeakers

There are eight graphic annunciator panels located throughout the terminal complex.  Each one is identical in design and provides the fire brigade with the ability to control a number of functions, as well as identify where the alarm signals are originating.

The fire alarm system interfaces with the following systems:

• 47 smoke extraction ventilators

• 35 elevators

• Air supply windows and doors

• Smoke exhaust vents

In the event of fire alarm system activation, a specific sequence of events occurs.

If a single smoke detector is activated in any area, or if a sprinkler system or smoke detector in a box cap store is activated, a signal is sent to the airport terminal control center and to the airport fire brigade watch center.  A terminal staff member is dispatched to investigate the cause of the activation.

However, if two smoke detectors or a manual pull station are activated, then the airport fire brigade is dispatched immediately.  The pre-recorded evacuation announcement begins.  This announcement is repeated in four languages (German, English, French and Turkish).  An alert signal is given first, then the voice recording, and then another alert signal is sounded before the recording is repeated in the next language.  Each message is about 30 seconds long, according to Bunthoff.

However, there are some exceptions throughout the terminal, said David Harriman, Head of Aviation Security and Emergency Planning.  In some areas, such as the office mezzanine, the building fire alarm system is activated if a single smoke detector is placed into alarm.  This decision was made after evaluating the risk in that particular area and determining the safest course of action.

Furthermore, some of the larger terminal areas are not automatically placed into full alarm.  In the departure area, for example, if two smoke detectors are activated, the fire brigade will respond and evaluate the conditions.  They will then make the decision as to whether to manually activated the evacuation signal or not.

SIDEBAR: The message that is played is: “Ladies and Gentlemen, your attention please.  Due to an unexpected incident we must evacuate this terminal building.  Please leave the building now following the emergency exit signs, remain calm and help anyone in difficulty.  Do not use elevators or escalators.  Please follow the instructions of the security staff.”

Some other actions that automatically occur when the building fire alarm system is activated include:

• Fire and smoke control doors are automatically closed

• Any emergency evacuation doors that are locked are automatically unlocked.

• Smoke extraction systems are activated

• Doors and windows are automatically opened to provide fresh makeup air for the smoke extraction system

• The air conditioning systems are automatically shut down

• Baggage belts and escalators are shut down.

In the 1996 fire, seven people were killed when the elevators they were using opened on the fire floor.  They were not able to escape, and the doors would not close because the smoke obscured the door’s photoelectric eye.

To avoid a similar tragedy, the elevators now interface with the fire alarm system.  If the building’s fire alarm system should be activated, the elevators automatically travel to the ground floor, where the doors open.  A recording advises the passengers that the elevator is out of service, and the doors remain open.

If a smoke detector on the ground floor should be activated by smoke in the area of the elevators, then the elevator car stops at the first floor, where the passengers can safely escape.

Evacuation

A review was undertaken of the different evacuation routes throughout the terminal.  To help facilitate moving people there are a number of doors, which are normally closed and locked, that will automatically swing open, creating escape routes.  Some of these routes discharge passengers onto the exterior of the building on the airside, but this is not a significant concern to the aviation authorities, said Harriman.  For the drills, those that evacuate to the airside do not have to pass back through security.  However, if it were a real incident, they probably would have to, according to Harriman.

There are 37 assembly points located throughout the airport grounds.  Uniformed supervisors that are on site 24 hours a day have been identified and assigned to particular assembly points.  Harriman said that it is important that they are uniformed because the public is more willing to take direction from someone in uniform versus civilian clothing.

Complete evacuation drills are conducted once a year in the terminals during normal operating hours.  This is coordinated with the airport tower to occur during a time when there are not planes arriving or departing, which generally means there is a 30 minute window of opportunity in which to carry out these drills.

In 1997, the first full evacuation drill involving the public was undertaken.  According to Harriman, there was a lot of resistance from within the organization to doing such an exercise.  The only other airport that he was aware of that had done a drill involving the public was Dublin airport.  Management eventually agreed to conduct the drill once they realized its importance.

A fire was simulated in the British Airways lounge by using a smoke generator.  It was estimated that there were about 1,700 people in the building, and it was evacuated within 9 minutes.  Passengers were directed to the assembly points located throughout the airport.  Those that had already passed through security were taken outside on the airside of the building. 

Harriman observed that business travelers, who were familiar with the building, had a tendency to evacuate via the same route that they entered.  Holiday travelers, however, who were not as familiar with the building, did tend to use the nearest exit.

When the videotape of the drill was later analyzed, it was noticed that many people did not evacuate until prompted by airport staff.  For this reason, management felt that they needed to train more airport staff in evacuation procedures.  Fire safety training is going to become a part of the training program when employees get badges to work on the airside of the terminal operations.  In addition, when the new Terminal B opens, the concessionaires’ employees will all be required to attend the fire safety training as part of their contracts.

There was also a problem with the voice annunciation system.  All of the different zones in the terminal work off of the same voice annunciation system.  Therefore, if a particular zone should go into alarm later in the incident, the voice annunciation for that zone is going to pick up mid-stream of the original message.  According to Harriman, by the time the later zones were going into alarm, the voice annunciation system was playing the English message.  Because of this, employees are trained to focus on the fact that the alarm has been activated and that the siren is sounding and to not focus on the particular words of the message.

In 2000, another drill was planned.  The planners attempted to conduct this drill without letting the airport staff know when they are going to occur in order to maximize its effectiveness in evaluating people’s behavior.  Employees and concessionaires were advised that it would occur sometime between November 1 and December 15, but were not provided with any more details.  However, word of the drill’s specific date and time started to spread, and companies were adjusting their rosters to ensure that their best people were on duty, according to Harriman.  When it became apparent that people knew when the drill was going to be held, the decision was immediately made to move it up a day earlier.

One of the adjustments they made in this drill, based on prior experience, was allowing the shops to keep one person in the store.  When they had completely evacuated the terminal during a previous drill, one of the concessionaires had to undertake a complete inventory, which was a time-consuming and arduous task.

There was some concern as to whether passengers would leave their luggage behind when they evacuated, creating a potential security risk.  However, that was not the case.  Also, restaurants were very cooperative and said they would provide replacement food or drinks to any customer that requested it.  Overall, the response to the drill was positive and there were significant lessons that were learned from this exercise.

Sprinklers

At the time of the fire the buildings were not equipped with fire sprinkler systems.  The fire broke out in a void space that contained combustible insulation, which served as a fuel and spread the fire throughout the void space.  Obviously, sprinklers in this area would have made a difference in terms of controlling or suppressing the fire.

Sprinklers have now been installed throughout the airport terminal buildings.  With the open ceiling plan, these systems are very prominently seen throughout the terminal building.

According to Bunthoff, to provide sprinkler protection in the new main terminal and in Pier B, they utilize 6 electrically powered fire pumps.  Each pump can discharge 3,000 lpm (793 gpm) at 9 bar (131 psi).

There is a total of 70,000 meters (230,000 feet) of sprinkler piping in the terminal, supplying 17,500 sprinkler heads.  Bunthoff reports that the discharge out of the sprinklers is 5 lpm over 1 m2 (0.123 gpm/ft2). 

Airport Fire Brigade Operations

At the time of the fire, the authorized staffing level of the airport fire brigade was 77 people.  As a result of the fire, according to Head of Firefighting Thomas Jeziorek, staffing levels have been increased to 136 fire fighters, with 22 fire fighters on each shift.

A new watch room, staffed 24 hours a day by two fire fighters, monitors all of the airports fire alarm and suppression systems.  They are able to remotely place smoke detectors out of service from the watch room, as well as communicate with the fire apparatus.

Since the cause of the 1996 fire was related to welding, a new hotworks permit program has been instituted.  Before undertaking any work, the worker or contractor has to fill out paperwork and conduct a risk assessment.  The plan of work is then taken to the fire department, which then checks to ensure they have fire extinguishers and other safety equipment in place.  The contractor is then responsible for providing proper protection at the site and when finished, must take the paperwork back to airport control to indicate they are done.  If a contractor should cause an unwanted alarm because of hotworks, they are fined 2,500 German marks (approximately $1,000 U.S. dollars).

In addition to its complement of ARFF apparatus, the airport brigade is now equipped with two structural fire fighting apparatus, one staffed with five fire fighters and the other with three.  Because of the on-duty staffing (22 fire fighters), they are able to respond to structural fires using these two pieces of apparatus without reducing the level of ARFF response below that required by the aviation authorities.

Düsseldorf municipal fire brigade

Changes have occurred with the Düsseldorf municipal fire brigade as well following the fire.  According to Peter Albers, a chief officer with the Düsseldorf municipal fire brigade, staffing has increased from 500 to 580 fire fighters.  In addition, three of the stations in the vicinity of the airport have added an additional fire engine.

Albers also reported that prior to the fire there were no standard operating plans for a response.  As a result of the fire, they have established protocols that range from F1 (low) to F4 (highest level of response).

There were problems with coordinating the operations of the municipal fire brigade and the airport fire brigade.  Prior to the fire, and currently, the two brigades do not regularly train together except for one major exercise a year.  To help in coordinating their operations, a single Incident Coordination Center has been established.  The purpose of the ICC is to bring together the multitude of different agencies and departments that need to be working together during an emergency.

Radio communications was a problem for the municipal fire brigade during the fire, and still is today.  In large buildings, such as the airport terminal, they may have to set up relays to transmit messages between various units.  However, there is now a common radio frequency that is shared by the municipal and airport fire brigades.

Emergency Operations Plan

According to Albers, the Düsseldorf Fire Brigade is responsible for reviewing and approving building construction plans for the airport.  One requirement that they instituted was that the airport have an emergency response plan before they would agree to approve any building construction.  They knew that if the plans were approved before this plan was developed that it would probably never happen.

In 1997, Harriman, was tasked with developing the emergency response plan.  The one that the airport had in place only addressed aircraft emergencies and did not include building incidents.  He started reviewing plans from other airports in Germany, and only one other airport had one that he considered credible.

A working group was formed to develop a plan specifically for Düsseldorf.  Part of the objective by forming this group was to get the plan accepted at all levels within the organization.  Because of the variety of operations and buildings at the airport, it was necessary to develop a separate evacuation plan for each building rather than a general one that could be applied airport-wide.

Düsseldorf Today

The Düsseldorf airport now has a comprehensive system of suppression, detection and evacuation in place to avoid a repetition of the tragedy that struck in 1996.  As the only airport that has ever suffered a tragedy of this magnitude, they want to ensure that it does not happen again.  According to officials, the changes that have been made in the fire protection systems and operating plans are steps in that direction.

Ed Comeau is the principal writer for writer-tech.com.  He is the former chief fire investigator for the NFPA and investigated the 1996 Düsseldorf airport terminal fire.

David Whittington is a divisional officer and senior airport fire officer for the British Airport Authority.  He also investigated the 1996 fire and worked with NFPA in compiling information for both the NFPA report and for this article.