Designing buildings to resist the worst effects of a terrorist bomb blast is becoming a key part of the specification process. Arup Security Consulting specialises in this type of work and has just won Security Consultant of the Year at the Security Excellence Awards 2004. It was also one of the few consultants praised by Lord Fraser in the report on the Scottish parliament building.
Here, David Hadden, associate director at Arup Security Consulting, gives five tips on specifying a blast resistant building – all practices that were implemented at Holyrood.
Laminated glass windows
If there is only one thing you do to reduce blast hazard in your building, make sure it is to insist on laminated glass for the windows. With plain glass, the occupants could be at serious risk from a vehicle bomb hundreds of metres away, not just from a direct attack on your premises. If the windows are double-glazed then at least the inner leaf should be laminated.
Before you put anti-shatter film on existing windows find out what sort of glass you already have. If it’s laminated then anti-shatter film will at best provide a marginal improvement in blast protection and in some cases might make the windows more likely to blow in.
Design cladding, glazed or otherwise, to span vertically from floor to floor, not horizontally between the perimeter columns. This means any blast load from the cladding can be resisted by the inertia of the whole building and the floor slabs without causing bending in the columns.
Places to shelter
Get an engineer with experience of blast effects to identify the best places in your building to take shelter in the event of a bomb alert outside but make sure there is adequate room, ventilation, water and access to toilets for all the occupants and that you have reliable communication links to the outside world; mobile phones may not work inside a basement or core. Be prepared to hold practice drills for your staff so that they know what to do in an emergency.
A vehicle bomb detonated inside a building is more likely to cause major structural collapse than one detonated outside. When planning the access to internal loading bays and car parks (if you really must have them) try to locate vehicle barriers outside the building footprint and provide a route for rejected vehicles that avoids them having to enter your building to turn around. Suspect vehicles should not be allowed inside the building.