Safety Glass and Security Glass

 

Safety and security glass serve related but different purposes.

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Safety glass is intended to reduce the likelihood of serious injury if someone falls against it or the glass breaks. Security glass is intended to make penetration or forced entry more difficult.

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The two principal types used in domestic windows and doors are:

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Toughened glass

Toughened glass is heat-treated to increase its strength. If it breaks, it fragments into many relatively small, blunt-edged pieces rather than large, sharp shards.

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It is widely used as safety door glass and in low-level glazing where there is a risk of accidental human impact. However, once toughened glass breaks, it generally falls away and leaves the opening exposed.

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Laminated glass

Laminated glass consists of two or more sheets bonded together with a plastic interlayer. If the glass cracks, the fragments are held by the interlayer rather than immediately falling out.

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This makes laminated glass suitable for both safety and security applications. Different glass and interlayer thicknesses can provide increasing resistance to impact and penetration.

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Where protection against forced entry is the priority, laminated glass will often be more appropriate than toughened glass alone.

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Window Security Glass

 

A security glass window should combine suitable glazing with a secure frame and locking system.

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Laminated glazing may be particularly worth considering for:

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• Ground-floor windows

• Basement and lower-ground-floor windows

• Rear and side windows concealed from view

• Windows accessible from a flat roof

• Glazing beside an entrance door

• Garage and utility-room windows

• Properties containing high-value items

• Windows in isolated locations

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The appropriate specification will depend on the size and position of the pane, the likely risk and the level of resistance required.

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Security glazing designed to resist manual attack is classified under BS EN 356. Where tested security performance is important, ask the supplier for the classification of the exact proposed glass rather than accepting a general claim that it is “strong” or “secure.”

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Safety Glass Windows

 

Building Regulations require suitable glazing in areas where accidental collision presents a greater risk.

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Approved Document K identifies critical locations including glazing:

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• In doors below 1,500mm from floor level

• Within 300mm of a door and below 1,500mm

• In windows and walls below 800mm from floor level

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Glazing in these locations should break safely, be sufficiently robust or be divided into suitably small panes.

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Safety glazing requirements do not automatically provide enhanced burglary resistance. Toughened glass may meet the safety requirement but laminated glass could provide greater post-breakage security.

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An installer should therefore consider both accidental impact and home security when specifying safety glass windows.

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Security Glass for Entrance Doors

 

Glazed entrance doors and their surrounding panels can be vulnerable because they are positioned close to handles, locks and cylinders.

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Security considerations include:

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• Laminated glazing

• Internally positioned glazing beads

• Strong door frames

• Multi-point locks

• Secure handles and cylinders

• Reinforced door panels

• Properly fixed side panels

• Suitable hinges and hinge protection

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Glazing immediately beside a door should not allow easy access to the internal handle or locking system if the outer pane is broken.

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Where a doorset is being supplied as a tested security product, the frame, glass, locks, hinges and hardware should match the tested specification. Changing one component can affect the performance of the complete doorset.

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Patio Door Security

 

Large glazed patio doors require particular attention because they combine broad areas of glass with movable panels and accessible locking mechanisms.

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Good patio door security depends on:

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• Suitable laminated or security glazing

• Multi-point locking

• Strong interlocking frame sections

• Anti-lift protection

• Secure handles and cylinders

• Internally retained glazing

• Reinforced frames

• Correct frame alignment

• Strong mechanical fixing to the building

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A high-security lock cannot work correctly if the door has dropped, the frame is distorted or the locking points no longer align with their keeps.

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Patio doors should open and close smoothly without the handle or locking mechanism needing to be forced.

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Sliding Patio Door Security

 

Older sliding doors can become vulnerable through worn rollers, basic locks or panels that can be lifted from their tracks.

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Possible sliding patio door security improvements include:

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• Laminated replacement glass

• Multi-point locking systems

• Anti-lift devices

• Reinforced interlocks

• Secure track construction

• Additional locks

• Replacement rollers and guides

• Correct adjustment of the sliding panel

• Internally fitted glazing beads

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Sliding doors should be inspected where the panel moves excessively within the frame, does not close squarely or can be lifted when shut.

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Additional locks may improve an existing door, but they will not overcome serious weaknesses in the frame or glazing system.

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Sliding Glass Door Security

 

Modern sliding glass doors can use very large panes and slim frame profiles. This makes the overall design of the system especially important.

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When comparing products, ask:

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• Is laminated glass included?

• Has the complete doorset been security tested?

• How many locking points are provided?

• Does the system include anti-lift protection?

• How are the glass units retained?

• Is the moving panel reinforced?

• What cylinder and handle protection is included?

• Does the test evidence apply to the proposed door size?

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Security performance should relate to the complete sliding glass door, not only its lock or glass.

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Security Glass for French and Bifold Doors

 

French doors have a central meeting point that must remain secure when both door leaves are closed.

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Look for:

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• Multi-point locks

• Strong shoot bolts

• Reinforced meeting stiles

• Laminated glazing

• Secure hinges

• Internally retained glazing

• Suitable threshold fixings

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Bifold doors contain several connected panels, hinges and locking points. Security depends on the integrity of every panel rather than the main access door alone.

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A bifold system should include secure panel-to-panel hinges, locking points at the head and threshold, anti-lift protection and correctly aligned frames.

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Internally Glazed Windows and Doors

 

Glazing beads hold the glass unit within its frame.

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With an internally glazed system, the beads are positioned on the room side. This prevents them from being easily removed from outside while the property remains secured.

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Older externally glazed systems may have additional clips, tapes or other measures to prevent removal of the glass. If you have concerns about existing windows, a repair specialist can inspect how the glazing is retained.

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Can Existing Glass Be Upgraded?

 

It may be possible to install laminated glass into an existing window or door frame, provided the frame can safely accommodate its thickness and weight.

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Before replacing the glass, the installer should check:

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• Frame condition

• Glazing-unit thickness

• Rebate depth

• Bead compatibility

• Hinge and hardware capacity

• Maximum permitted sash weight

• Existing locks and reinforcement

• Frame-to-wall fixings

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Simply fitting heavier glass without checking these elements could affect how the window or door operates.

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Where the complete frame is weak or several components have failed, full replacement may provide a more secure long-term solution.

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Security Film

 

Security film can be applied to some existing glass to help retain broken fragments and delay the creation of an opening.

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Its effectiveness depends on:

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• Film thickness

• Glass type

• Quality of application

• How the film is anchored at the frame edges

• Pane size

• Existing frame strength

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Film applied only across the visible area of a pane may not perform in the same way as purpose-manufactured laminated security glass.

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It can be useful in suitable situations, but homeowners should ask for clear information about its tested performance and installation method.

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What Is a Bulletproof Glass Window?

 

The term bulletproof glass window is commonly used, but the more accurate description is bullet-resistant glazing.

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No glazing should be assumed to resist every type of firearm or repeated attack. Specialist systems are designed and tested for defined threat levels using particular combinations of glass, polycarbonate or other interlayers.

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Bullet-resistant protection requires more than the pane itself. The frame, glass retention, joints, surrounding structure and installation must all provide a corresponding level of resistance.

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This type of glazing is unusual in ordinary domestic work and is more commonly associated with buildings exposed to a specifically assessed security risk. Laminated glass products can be engineered for bullet and blast resistance, but these are specialist specifications rather than normal residential double glazing.

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Homeowners should not describe ordinary laminated or toughened glass as bulletproof.

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Security Standards

 

When purchasing new windows or doors, ask whether the complete product has been tested to a recognised security standard.

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PAS 24 is used to assess the enhanced security performance of doorsets and windows. Secured by Design provides guidance on tested windows and glazing that satisfy relevant security requirements.

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Depending on the window or door design, security specifications may require laminated glass in accessible glazed areas, particularly where breaking the pane could provide access to non-key locking hardware.

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The supplier should confirm:

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• Which standard has been achieved

• The exact product covered

• The tested sizes and configurations

• The glass specification

• The locks and hardware included

• Whether the proposed installation matches the test evidence

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Repair or Replace?

 

An existing window or door may be improved through:

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• Laminated replacement glazing

• New locks or gearboxes

• Replacement handles

• Hinge adjustment

• New rollers

• Anti-lift devices

• Improved glazing retention

• Frame realignment

• Stronger keeps

• Repair of damaged timber

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Complete replacement may be more suitable where the frame is warped, cracked or inadequately fixed, or where several security components have failed.

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A specialist should inspect the full installation rather than recommending glass replacement without checking the frame and locks.

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Planning and Building Regulations

 

Replacing glass within an existing frame will not normally require planning permission. Complete window or door replacement may be possible without planning permission where the new installation has a similar appearance, although additional controls apply to flats, listed buildings, conservation areas and properties affected by an Article 4 Direction.

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Building Regulations may apply when complete windows or doors are replaced and when new openings are created. Requirements can cover safety glazing, energy efficiency, ventilation, structural support and means of escape.

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Security improvements must not prevent a required escape window or door from operating correctly.

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Find Trusted Security Glass Installers

 

Security glass should be selected as part of a complete window or door system. The frame, glazing, locks, hinges and installation must work together to provide effective protection.

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APN Double Glazing can connect homeowners with experienced local installers for laminated security glass, safety glazing, secure windows, entrance doors, French doors, sliding patio doors and bifold doors.

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Get in touch for expert advice and a free, no-obligation quote for improving the safety and security of your windows and doors.