Designing Against Terrorism: A Component of All Designs
October 01, 2002
Appeared in New York Construction News
Although it has been a mere 13 months since the attack on the World Trade Center (WTC), designing buildings against terrorist attacks is an increasing component of all design work today.
Richard Tomasetti, co-chairman of the Thornton Tomasetti Group (TTG) of New York said, designing against terrorist attacks must be done cost-effectively and with a vulnerability analysis. A vulnerability analysis must also be conducted when retrofitting existing buildings and structures, he added.
Some of the solutions can be based on previous learning experiences such as seismic design, Tomasetti said, noting that seismic design takes into account major damage to a building without its collapsing and with the emphasis on life safety.
He also said the design community could learn from what standards are being developed by the federal government for their critical facilities as well as other codes throughout the world. ''I think one of our major issues is whether all of the tri-state region should be adopting the international building code and through that the design community can develop more universal approaches to the design of its buildings,'' Tomasetti added.
''Another major issue,'' he continued, ''is how do we develop the criteria for the protective design of buildings without giving valuable information to those who may want to destroy them. In the military, this is done through secret clearances and on a need-to-know basis.
This would be impractical for civilian projects. Therefore, the solutions lie in designing buildings that would have a greater resistance to all forms of hazards -- seismic, wind, fire and explosives.''
Integrated, performance-based design is one solution to having a greater resistance to hazards.
Performance-Based Design Carl Galioto, a technical partner at Skidmore, Owings & Merrill of New York, added that the design community is looking at ''integrated, performance-based design.'' Criteria for this includes considering the threat, fire load and the ability for tenants to evacuate a building.
''We need to look at the interdependency and the independence of systems'' and ''independence must exist so space can be kept tenable to facilitate evacuation,'' Galioto said.
Elaborating, he noted that designers must look at how a building is exited. ''Fire-rated stair enclosures are one measure of safety. Another is total evacuation,'' he pointed out.
He said his firm has used computers to simulate evacuations. ''We compared the length of time to evacuate with the fire safety of the stairs,'' Galioto added.
A building's height is also a factor, he continued, emphasizing that the fire rating of stair enclosures need to be increased. Stairs also need to be made wider. ''This will allow more time to evaluate a taller building in less time,'' he said.
Other safety measures he mentioned include pressurized vestibules and dedicated elevators for firefighters. Another design solution involves bringing service elevators closer to the building core, having direct access to fire stairs and adding doors to elevator stop doors to prevent smoke from going up elevator hoists to other floors.
Terrence Gillick, a partner with The Syska Hennessy Group of New York, said blast, biological and chemical weapons must all be considered threats to today's buildings. These threats, he said, should be addressed with an in-depth plan that protects the building, its interior, its exterior and of course, its tenants.
Gillick said the first thing that must be addressed are security policies and procedures. A comprehensive security plan must be developed and implemented. He recommended that this plan included an integrated electronic security system, an automated building security system, contract security personnel and keeping local law and fire officials informed and integrated into the plan.
Elaborating, he said the first zone is the building interior. This should include a main security console in a building's lobby, employee and visitor badges, interior detectors and alarm systems, locking systems, closed circuit television and guard tours.
Gillick said the second zone involves protecting the perimeter of a building. This means looking at window coatings, hardening the building's exterior and curtain wall, incorporating landscaping and lighting, HVAC filtration and treatments and protecting a building's mail facilities.
The third zone involves using landscaping elements to protect a building's grounds and the fourth zone involves sidewalks and property boundaries, including utilities, roadway barriers and parking.
The fifth zone calls for protecting parking structures and lanes using a vehicle identification system and the sixth zone calls for integrating the public domain such as streets, emergency services, police and firefighters.
Impact of Collateral Damage Ted Rittenhouse, a managing principal of Weidlinger Associates of New York, said the impact of collateral damage that result from a terrorist attack must also be considered in today's designs and retrofits. This includes the need for perimeter protection such as stationary and operable bollards, surveillance cameras, the need for proper lighting and the use of rollup garage doors for off-hour protection.
Rittenhouse also emphasized the need for turnstiles in a lobby along with a magnetometer, an x-ray machine, the need to strengthen columns in prescreened areas and the need to strengthen windows and walls.
He suggested that strengthening a building's facade to hold windows in place and prevent wall failure could enhance wall sections.
In addition, Rittenhouse said bullet-resistant glass could be used and he recommended there be strong attachments of windows to mullions and that insulated glazing with a laminated inner pane be used.
Rittenhouse added that progressive collapse should also be part of a building's design. He recommended that column beams and joists be reinforced and noted that ''optimal blast design protection is keyed to the criticality of a facility.''
He suggested that the level of protection in a building be tailored to each client's own needs and recommended that whatever a client decides to do should be incorporated early into a project's design.
On the topic of existing buildings, Gillick said evacuation is a paramount concern. Galioto said existing buildings could have enhanced security by having an effective communications system that will allow police and firefighters to use their own communications equipment in a building. Rittenhouse said tenant education of exits is key and added that film glass can be used to prevent shards of glass after an explosion from going everywhere. ''Film glass,'' Rittenhouse explained, ''will reduce injury to people and damage to a building.''
''Firms that have changed and adapted as a result of the terrorist attacks have created market opportunities, such as in airport security, environmental security, power distribution and in the reinforcement or redundancy of bridges and roadways,'' according to Jay Simson, executive director of the New York Association of Consulting Engineers in Albany, N.Y.
Other Issues Insurance and recruitment are two other key issues top design firms are concerned about in the coming year.
Simson said the rising cost of insurance is affecting everyone. ''In some areas, insurance isn't available and the potential of litigation in the future could be detrimental to design firms in the future. He said one solution would be insurance reform at the state and federal levels.
Increased claims are already here. According to John Hennessy, chairman of The Syska Hennessy Group of New York, ''design firms are seeing an increase in the number of claims made against them and the cost of their insurance is rising precipitously.''
''The insurance crisis is mostly a result of the events of Sept. 11, 2001 and the stock market decline,'' Hennessy added, noting that ''firms can look to change the coverage and limits to help mitigate these increases. The rise in claims is somewhat a result of the declining economy. People look to get 'whole' at the expense of their designers and contractors when other things are not going as well. An aggressive approach to defending the claims and a greater focus on quality design will mitigate these problems.''
Kevin J. McMahon, chairman and chief executive officer of Edwards & Kelcey of Morristown, N.J., said the higher cost of insurance ''is being passed along'' and ''it will definitely increase the cost of construction.''
Will design firms face a shortage of quality people? Simson believes so, noting that fewer and fewer individuals are graduating from engineering schools. One possible solution is to encourage more young people to get involved in engineering and let them know it is a good, solid profession.
Hennessy said the labor shortage for top design firms has existed for several years. ''While the pace of work has slowed down, the number of qualified people is still short of the need of them. The recession of a decade ago caused us to lose many able people to other industries and other parts of the country. The industry is still suffering from this. The solution is for design firms to be more aggressive in their approach to the education of their team. For example, we have implemented a formal mentoring program to improve the coaching skills of our team and to speed up the education process of our younger team members.''