Can Australia's building codes prevent a WTC-style disaster?

Planning a response to a terrorist attack or other emergency or crisis event requires an understanding of the dynamics and rapid developments that result from these disastrous unwanted actions. A poor response to any crisis or emergency situation, including an attack by a deranged person or persons who are politically or ideologically motivated towards undertaking terrorist actions, may well affect an organisation's ability to survive.

In today's environment, such events include fires, explosions, floods, earthquakes and the many emergencies that result from social disorders, such as civil unrest, hostile actions by deranged persons and acts of terrorism.

A crisis management plan, however, is of little value if the planning team has not understood the basic provisions of the Building Code of Australia and the protection available from establishing and maintaining facilities such as fire isolated stairways and passageways, safe refuge areas and life supports.

Having a crisis management plan and trained personnel, and being able to respond to the crisis event is a basic necessity for any organisation if it is to survive in today's destabilised environment.

All resultant administrative, procedural and crisis response actions should be in compliance with legislative and other mandatory requirements, Australian and International Standards, and community expectations. These may include:

• Federal, State and Local Government Acts and Regulations.
• Police and Emergency Services Acts and Regulations.
• Australian Standards, and in particular those referenced in legislation such as the Building Code of Australia, that may be applicable to a particular crisis event.
• International Standards and working groups covering building fire safety design, quality and the environment.

Of particular importance is the need to certify the competency level of those persons responsible for implementing and managing the response and recovery actions that follow a crisis event.

An act of terrorism

On September 11, 2001, nineteen terrorists hijacked four commercial airliners, crashing them into the World Trade Centre buildings.

Two aircraft impacted the twin towers of the World Trade Centre at an estimated 350 knots. This fact, combined with the large amount of fuel on the aircraft, led to severe structural damage within the buildings. This structural damage, combined with the effect that the resultant inferno had on the support columns within the buildings, caused their eventual collapse. The collapse of the buildings took some 104 minutes after the initial impact for the 110 floors of the North Tower and 47 minutes after initial impact for the 110 floors of the South Tower.

The buildings were designed to resist an accidental collision with a small plane - not a direct hit from an aircraft laden with nearly 90,000 litres of aviation fuel. The twin towers were essentially hollow steel tubes with holes punched in the sides. The steel core, which supported service risers, lift shafts and fire escapes, was linked to the outer steel support floors.

It has been estimated that the initial impact of the aircraft would have knocked off the fireproof cladding on supporting structural steel members. The resultant fires would have reached 1000°C very quickly. Without cladding, the raw steel columns would have rapidly heated up, softened and begun to deform.

The facade was, in effect, a prefabricated steel lattice with columns having approximately one metre centres, acting as wind bracing to resist all overturning forces; the centre core taking the gravity loads of the building. For practical purposes, the office space had no interior columns.

It has been argued, however, that these external supports withstood the intensity of the fire better than more conventional internal steel column supports would have. The argument given claims that this allowed a greater number of persons to evacuate than would have been possible if conventional support columns had been used.

In Australia, such a 'high-rise' building would have been of Type A construction ie, most fire resistant, with the structural sufficiency, integrity and insulation of the supporting conventional steel columns required to meet the highest fire resistance levels. Automatic fire sprinklers would also be required.

Automatic fire sprinklers were not installed on the floors struck by the aircraft.

The question remains, would a fire sprinkler system, conforming to National Fire Protection Association of America (NFPA) specifications, have protected the vital structural elements from failure and thus the buildings from collapse?

The Australian building code

The Building Code of Australia (BCA) is a manual for technical people involved in the construction and maintenance of buildings: the building designer, the building architect, the builder and the building controller.

It is also of importance to other parties involved in a building refurbishment and those regulatory officials, fire service personnel and building surveyors and occupiers who are involved in assessment and checking of fire safety designs and fire safety standards within a building.

The objectives of the BCA are:

• To provide for the life safety of the buildings occupants.
• To provide for the safety of fire fighters.
• To provide protection for adjacent buildings.

In applying the BCA the regulator seeks to provide a comprehensive collection of technical requirements to be imposed by local government in the interests of safety, health and the amenity of the Australian community. The 'loss control' objectives of the BCA include the following factors:

• Limiting structural and fabric damage from an emergency situation.
• Limiting building content and equipment damage.
• Maintaining business operations and financial viability.
• Protecting corporate and public image.
• Protecting Australia's heritage in older or historically significant buildings.

The BCA groups buildings into thirteen classes in order to facilitate reference to different sorts of buildings. To complement this, the BCA specifies how to deal with buildings that incorporate parts for different purposes or those formed by joining two or more buildings together.

The BCA lists all Australian and other design standards that must be met if the building is to conform to proper design and safety principles.

When deciding the building classification under the BCA, the designer has to consider the purpose of the building. The purpose governs the 'Risk' of fire and other damaging events, and the effects those damaging events may have on the structure.

For example, the purpose will govern the following design features:

• Fire resistance and stability.
• Compartmentation and separation.
• Protection of openings.
• Structural adequacy, integrity and insulations.

Other considerations include waterproofing, sanitary facilities, room sizes, light, ventilation and noise control.

If we applied the Australian BCA to the twin towers that made up the New York World Trade Centre, we would say that the buildings consisted of multi or mixed classifications, including hotel residential (Class 3), office use for professional or commercial purposes (Class 5), shops and other facilities for the sale of goods by retail and the supply of services direct to the public (Class 6), a public car park (Class 7) and areas of a public nature (Class 9).

Special design would be required to ensure that the structure, fire resistance ratings, access and egress and services and equipment were adequate for the classifications incorporated within the buildings.

Access and egress from the buildings would have to meet defined provisions for escape such as the construction of exits and access for special populations including people with disabilities.

Services and equipment requirements would specify automatic fire sprinklers, fire-fighting equipment, automatic smoke detection, smoke hazard management, lift installations, emergency lighting, exit and directional lighting and signage, emergency warning and evacuation systems and their maintenance.

If built in Australia, the twin towers would have had to have been of a Type A fire resisting construction, ie, the most fire resisting construction available. This would be based on horizontal and vertical compartmentation construction in which the structural elements (such as the support columns between floors) are able to withstand burnout of the contents.

The buildings would have automatic fire sprinklers installed to Australian Standards. Whether or not these automatic fire sprinklers would have protected the structural members enough to eliminate their deformation and thus collapse requires some further research.

It is clear, however, that the required fire resistance rating of the structural members of a high-rise building in Australia, would have withstood the inferno better than the floor membrane used in the twin towers.

In Australia, internal support columns would, in all probability, have been clad with concrete to provide the necessary structural adequacy, integrity and insulation fire resistance levels (FRL).

The success record of automatic fire sprinklers in controlling fires and thus offering further protection to structural members of a building is remarkable. Previous research has shown that automatic fire sprinklers have a 99 per cent success rate in this country.

Planning for emergencies

Building designers, when considering high-rise buildings and industrial complexes, base their fire safety recommendations on the provision of passive fire protection, fire detection, warning systems and fire suppression installations on the Building Code of Australia.

The missing element being, the provision of a trained and competent emergency control organisation.

The number of high-rise and other public assembly buildings that do not have an established emergency control organisation can be best described as a scandal. It has been estimated that less than one quarter of the buildings requiring emergency evacuation procedures actually have them.

Few emergency control organisations existing in Australian, covering high rise, public assembly and other large population buildings and structures, train their wardens in major emergency or crisis events, such as planning what to do in the event of a terrorist attack. Indeed, they satisfy themselves that the annual or six monthly 'fire evacuation' meets their needs.

In other cases, emergency control organisations fail to include special considerations to both the primary and secondary means of escape, in times of an emergency or other crisis event.

The remedies are in training and educating the occupants of high-rise buildings and public assembly and other large population structures in their responsibilities when under threat from an emergency or crisis event, such as fire, bomb threats, sabotage or deliberate attack from protest or terrorist groups. Wardens who are required to take control in an emergency situation or crisis event must be independently assessed as competent to undertake such duties.

Planning for safety

Firstly, during an emergency, for whatever reason, fire, bomb threat, gas explosion, threat to the physical safety of the occupants from uncontrolled protest groups or terrorist attack, few occupants will be asked to travel by the 'normal' means of egress when evacuating their building or other structure.

Yet, it is highly probable that these persons will have little knowledge of the safe means of egress required by the Building Code of Australia and what safety measures have been designed into the building.

Additionally, most industrial and commercial complexes require their employees to enter and leave the premises via a security checkpoint. This checkpoint often serves as the main entry and exit area which employees pass through, at times under the scrutiny of electronic surveillance systems. Yet, during an emergency those same people may be expected to leave the complex by quite different routes.

Many have grown up with these arrangements and therefore never question them. What occupational health and safety professionals and persons interested in the safety the community need to question is how well the occupants of these complexes have been educated or trained in the special arrangements to be followed whenever an emergency or crisis event occurs.

Current Australian standards, the Building Code of Australia and relevant legislation, have all addressed the general requirements for the provision of minimum fire safety. These may not, however, achieve a safe and orderly response to an emergency or crisis event.

It should be remembered that the Building Code of Australia includes such items as the design of fire door furniture and the necessary hardware to be installed to ensure that people can evacuate even under panic conditions.

What is missing in most cases, are suitable emergency response procedures, tailored to the needs of the building or structure involved. Procedures which detail the provisions of the building code so that wardens and others can have confidence in the facilities provided.

Professional liaison

The professional interaction between fire safety and security personnel has, in many cases, ensured that standards remain evolutionary and the design criterion for all fire safety features, such as the fire door furniture, is in line with the latest technology.

Both the building designer and the building owner have an adequate range of suitable fire safety products and electronic surveillance systems to choose from, so as to ensure that the necessary escape route is available during an emergency or crisis event.

The problem remains, however, that many employers and building owners fail to educate the building occupants and/or their employees in their individual and group responsibilities, when placed under emergency conditions.

Solving the dilemma

If a major fire was to occur or a bomb was to be detonated within or adjacent to the building, how would the occupants evacuate? Via the fire isolated stairways under controlled conditions, supervised by Floor and Building Fire Wardens? Or would chaos result?

Occupational Health and Safety personnel must also play their part. While diligence is required to overcome the 'locked fire door mentality' of some employers, an emphasis is required to move these same employers towards planning for integration of their emergency and crisis response procedures with their security provisions, so as to mitigate the damage and disruptions that their business could suffer, if an emergency or crisis event was to arise.

Priority consideration must by given to these issues, as the populations which occupy our cities' high-rise buildings today often exceed 6000 persons with sporting stadiums being designed for populations of 90,000 or more.

The answers here are know your building and know the provisions made for the safety of the occupants and design your emergency and crisis response team around the proper use of the facilities provided.