What is an Angel Ventlock® ?

Angel Ventlock ®, our Patented Window Restrictors, sometimes referred to as Child Safety Restrictors or Window Opening Control Devices (WOCD). They are used to limit the opening of a window to help prevent falls and keep children safe. In addition, Angel Ventlock ® provide an extra level of security as they make it difficult for an intruder to fully open the window.

Angel Ventlock® limits the opening of your sash but do not prevent it from being opened slightly. Thus allowing ventilation. In addition, it makes it difficult for children to open the sash. Adults, however, can easily disarm the Angel ventlock® as no key is required. This also means our non-locking versions won’t impede fire egress. Never fit locking devices to egress (windows you would escape through). The device resets or ‘arms’ itself after each closure of the window to ensure the window will not open beyond the safe limit unless you want it to.

Child safety is at the heart of our Angel Ventlock® design. It’s an unfortunate fact that every year over 4,000 children fall through open windows. Of those, 15-20 are killed and at least 80% are under the age of four. (Source: Home Safety Facts and Figures, RoSPA). Fitting window opening control devices will reduce this statistic.

Angel Ventlock® are used by some of the world’s largest window companies and has been tested to the most stringent International (ASTM F2090-2010) and European (BS EN 14351-1:2006) Standards. Angel Ventlock® surpasses all forced entry tests, allows for egress and automatically resets when the window is closed. The British Standard states ‘Safety restrictors should be fitted to any accessible opening window where children or adults are at risk of falling out.

An accessible window is defined as one where any part of it is 1500mm or less above floor level. Angel Ventlock® are suitable for single and double-hung sash windows and sliding and gliding windows too

The legislation

Where do Safety restrictors need to be fitted?

BS 8213 Part 1 States:

a) Safety restrictors should be fitted to any accessible opening window where children or adults are at risk of falling out. ‘An accessible window is defined as one where any part of it is 1500mm or less above floor level. This means that any accessible window with a cill height of less than 1500mm should be fitted with compliant safety restrictors.’

b) If safety restrictors are to be fitted to fire escape windows, then the positioning of the device should be such that the occupant does not have to spend time searching for the release. The release can be achieved without prior instruction and cannot be confused with other operations.

What type of Safety restrictors should I fit?

BS EN 14351-1:2006 States:

Safety restrictors should operate so that they:

a) Limit the initial window opening to less than 100 mm.

b) Cannot normally be released by a child under 5 years old (ASTM F2090 defines that the release mechanism must be operated by either 2 single actions or 1 dual action).

c) Are readily identifiable and capable of being released by an adult (without prior instruction) on windows suitable as a means of escape in case of fire.

d) Re-engage automatically when an opening sash is returned to the initial restricted opening position, or to a closed position. Using the sash to set the device is not permissible (ASTM F2090).

e) Are not lockable on windows suitable as a means of escape in case of fire. Clear written information on the operation of the fitted safety restrictors, and any potential risks or limitations in use, should be provided to owners and occupiers by window installers. When it is necessary to open the window fully, return the window to a position where the restrictor automatically re-engages as soon as possible.

Safety restrictors should be tested in accordance with DD CEN/TS 13126-5:2004 and should be:

a) Durability tested under DD CEN/TS 13126-5:2004 7.3, grade 5,

b) Strength tested under DD CEN/TS 13126-5:2004 7.4,

c) Corrosion resistance tested under DD CEN/TS 13126-5:2004 7.5, and conform to BS EN 1670 Class 3 (96 hours) or better.

Note: Restrictors can be either an integral part of the window operating gear or a separate item of hardware that can be fitted to a window at the time of manufacture or later.

Restrictors should meet the requirements of BS 6375-2. EN 14351-1 clause 4.8 “load-bearing capacity of safety devices” specifies testing in accordance with EN 14609 or EN 948 at a load of 350 N.

Always reference ASTM F2090-2008, 2010 and 2017 when specifying Window Opening Control Devices.

Our Top 10 Window Safety Tips

We have compiled a list of the top ten window safety tips to guide you and your family – all tips should be observed


1. Install child safety devices that comply with ASTM F2090-2008, 2010 and 2017 standards

2. Teach your children not to play near windows

3. Close and lock your windows when children are around

4. Only open windows that children cannot reach or are secured with compliant locks

5. Keep beds, furniture, and anything a child can climb on away from windows

6. Do not depend on insect screens to prevent falls, they are not designed for this purpose

7. Repair broken windows or non-working parts as soon as possible

8. Open windows from the top, not from the bottom

9. Supervise your children as they play

10. Never leave young children unattended near open windows