“During a bomb blast much of the brickwork will crumble, fire will erupt and smoke will rise. Security managers presiding over new build projects should take time out with the building design team to look at minimising these effects as best as they can.”
Chris Bowes, defence sector director at consultancy TPS Consult, is an expert in this particular arena. “First you need to define the threat,” Bowes told SMT. “Then you need to look at client requirements and the importance of shelter areas.”
Bombs will typically be hand delivered (ie letters containing a few ounces of explosives, packages or suitcases with a maximum explosive charge weight of 15 kg) or vehicular-based devices (typically ranging from car bombs containing 70-100 kg of explosives to lorries – such as those used at Bishopsgate and at South Quay in London’s Docklands – where explosive weights of 1,000 kg may need to be considered).
“Once the nature of the threat has been defined,” continued Bowes, “the protection level required to limit its effect should be determined, both in terms of building damage and personal injury.”
In truth, this protection will be a mixture of architecture (which can affect the site layout orientation and building planning, etc), security (where physical and/or electronic measures are deployed to deter the threat) or building hardening (whereby the structure is enhanced to provide better performance in blast situations).
According to Bowes, there are two Golden Rules for blast protection. “First, keep bombs out of buildings,” he stressed. “Internal explosions are considerably worse than those that take place outside.
“Second,” he added, “maximise the distance between the site of possible explosions and the building to be protected. Blast energy is inversely proportional to distance.”
In addition, security and safety professionals should note that there are a number of structural and architectural features which should be encouraged in building design to provide better degrees of protection.
