The use of glass within a building may increase the risk to occupants if the building is subjected to blast pressures from a device, whether deployed internally or externally.
It is therefore important to understand how you can mitigate some of the risk by specifying:
- the most appropriate glass types to be used
- fixing systems and methods that will in turn improve the performance of the glazing
The measures detailed below and in the linked guidance note are suitable if you are considering general mitigation measures as part of your overall security strategy and they may be achieved through minor variations to your overall glazing specification.
Additional advice should be sought from a blast engineer from the Register of Security Engineers and Specialists (RSES) if a higher level of risk from improvised explosive devices has been identified in relation to the building you are concerned with. In this case a more detailed blast protection strategy will need to be developed to bring down the higher levels of risk.
Further detailed guidance can be found in the related pages below.
The elements impacting on the security resistance of internal glazing are:
- the type and thickness of the glass
- how the glazing is fixed to the adjoining surfaces - this will include the type of frame/connections, how the frame/connections are fixed to the adjoining surfaces and how the glass is fixed into the frame/connection
- if the balustrade or glass partition is designed as a protective barrier to prevent falling or just to be used as demarcation to guide people
Blast resistance in internal glazing systems is achieved through the specification of the glazing type and then improving the performance of the glazing system by ensuring it is fixed with the most effective method. The main points are summarised below with important detail provided in the guidance note.
When selecting the glass type, consideration should be given to the following:
- it is recommended that laminated glass is used in all internal glazing systems to minimise the hazard from a blast load (some laminates perform better than others)
- thermally toughened or heat strengthened glass may be used to improve the performance of the laminated glass
Fixing systems and methods
The blast resistance of glazing can be improved through the correct specification of the overall glazing system. In addition to the glass type this includes the following elements:
- the use of the appropriate channels to hold the glass to a combination of the floor, wall or ceiling
- how the glass is bonded into the fixing channel - the use of gaskets or structural silicone can be used, with the latter providing a stronger connection
- the type, size and number of fixings that are then used to hold the channel to the floor, wall or ceiling
- in all cases structural silicone must be applied by a competent person using the correct products and methods