Enhancing security

Windows can be vulnerable to intruders, to a blast attack when flying shards of glass create extreme hazard, to spread of flame and even a firearms attack. Specialist window security is also required in settings such as laboratories and mental health facilities. A fully independent secondary window frame creates a second discrete protective barrier that can include a range of security features to meet different risks.

Key Benefits

  • Peace of mind
    Burglary can be a very disturbing and disruptive experience

  • Duty of Care
    Those responsible for buildings have a duty of care for employees and visitors

  • Insurance
    Cover and premiums can be dependent on security measures.
    Museums with high value exhibits must meet strict security guidelines to benefit from the Government Indemnity Scheme.

Intruder protection

Frames, locks and fixings must resist driving force and levering; if the glass is vulnerable it must be difficult to break. Specifications will depend on the level of risk.
Risk Level Risk description Treatment Standard
Low Guarding against an opportunistic attack by a thief who wants to work quickly and with the minimum chance of detection Standard frames with simple locks and toughened or laminated glass None
Medium A more determined attack using stealth to avoid breaking glass, thus creating noise and drawing attention Robust frames with multi-point locking to opening panels and a choice of anti-bandit laminated glass PAS24:2016 
Secured by Design
High A planned, determined and sustained attack on both the glass and frame Enhanced frames with multipoint locking to opening panels and glazed with a specialist secure glass LPS 1175
Intruder resistance of Selectaglaze secondary glazing Selectaglaze products are tested at the BRE (Building Research Establishment)  Standards and accreditations
  • Building Regulation Approved Document Q: security, dwellings.
    This covers both new build and change of use and requires windows and doors to meet the security requirements of PAS 24
  • PAS 24:2016 – Enhanced security performance requirements for doors and windows.
    This standard simulates forced entry using static loading as well as manipulation with simple tools. The test does not involve glass breakage and so replicates a stealth attack 
  • LPS1175 – A loss prevention standard from the Loss Prevention Certification Board focussed on resistance to forced entry by a range of building components including doors, windows, grilles and shutters. There are eight security rating (SR) categories to cover different threat levels and attack tools 
  • Secured by Design – The official police security initiative to improve the security of buildings and their surrounds. Products that meet the security requirements of PAS 24 are awarded a 'Police Preferred Specification'

Blast mitigation 

A vehicle bomb will shatter standard glass at a distance of more than 100m and glass shards will cause injury to people and damage to sensitive equipment. To resist the pressure from a blast wave frames, locks and fixings must be designed to absorb and spread the load and glass must be laminated with a polyvinyl butyral (pvb) interlayer. Under load this stretches and holds the glass intact to prevent formation of damaging shards. The selection of frame and glass will be dependent on the risk. 
Risk Level Risk Description Treatment Standard
Low The building is not a direct target, but its commercial or public use may impose a ‘duty of care’   Standard frames with simple locks and 6.8mm laminated glass   ISO 16933 
Level EXV45 
Medium The building is in close proximity to more sensitive buildings and hence could be more vulnerable   Robust frames, multipoint locking to opening panels, 6.8mm laminated glass with deeper edge cover and stronger structure fixings   ISO 16933 
Level EXV33 
High The building is a potential direct target on account of its use or ownership and is likely to have a number of protective strategies   Enhanced frames designed to absorb higher levels of blast load, secure multi-point locking to opening panels, laminated glass with minimum 1.5mm pvb interlayer (7.5mm, 9.5m, 11.5mm) and secure structure fixings   ISO 16933 
Level EXV25 
Blast resistance of Selectaglaze secondary glazing Selectaglaze products are tested at arena trials conducted by Comblast using DNV GL’s Spadeadam test centre. Classification codes are EXV(X) with EXV referring to a vehicle bomb and X being the stand-off in metres.

  • ISO 16933:2007 Glass in building — Explosion-resistant security glazing
    A test to determine the air blast resistance of security glazing using a range of charges at different distances. 100kg TNT equivalent is generally used to simulate a small vehicle bomb. The target can be positioned at a number of distances, or stand-offs, between 45M and 10M.

Ballistic protection

Protection from firearm attack requires steel reinforced frames and traditionally very thick laminated glass. Thinner and lighter compositions are made by laminating glass with polycarbonate and this material is therefore more suited to secondary glazing.

Ballistic protection of Selectaglaze secondary glazing   Tested by Wiltshire Ballistic Service 

Standard EN 1522/1523 : ‘Windows doors shutters and blinds – Bullet resistance – requirements and classification and test method’ -  The standard has eight classification levels covering resistance to penetration of glass and framing by handguns, rifles and shotguns.

Fire protection

Fire resistant secondary glazing can help protect windows in proximity to a fire escape or an adjacent building. Fire resistance of Selectaglaze secondary glazing Selectaglaze product is tested by Chiltern international Fire and is rated for integrity alone.  Standard
  • BSEN 1363-1: 1999, BSEN 1364-1 :1997 ‘Fire resistance tests. General requirements/Fire resistant tests for non-loading bearing elements. Walls’ 
Security rating table
Test Type Physical Attack Ballistic Attack Blast Mitigation   Fire Resistance
Test Standard PAS 24: 2021 SBD LPS 1175 EN 1522 ISO 16933  BS EN 1363-1/ 1364-1
Rating Level Single Level SR1  SR2 SR3  FB4 (Magnum Handgun) EXV 45 EXV 33 EXV 25 EXV 15  30 minute integrity 
S10 HS - - - - - X - - -
S15 HS - - - - - - X -
S80 HS X - - - - - X -  
S85 HS - X - - - - - X
S20 VS - - - - - X - -
S25 VS X - - - - - X -
S90 VS X X
S95 VS - X
S41 HC X X
S45 HC X X
S50 HC - X
S40 FL X
S42 FL - X
S46 FL X X -
S43 DFL - - -
S55 DFL -  X
Other secondary glazing benefits

Security secondary glazing testing footage

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