When and Why are Window Restrictors Needed?

Window restrictors are a useful additional safety feature that can be added to your window, preventing the window from opening past a certain point.

What are window restrictors?

Window restrictors are a useful additional safety feature that can be added to your window. Restrictors prevent the window from opening past a certain point, meaning you can achieve adequate ventilation, with less risk than a fully open window.

When are they needed?

There are many types of buildings that may require window restrictors by law. Under health and safety legislation, window restrictors are required where occupants are vulnerable to the risk of falling, have access to windows, and the windows are at a height that falling out of them risks injury.

All public organisations have a legal obligation to provide a safe environment. Workplaces must have a risk assessment conducted by a ‘competent’ person to determine if window restrictors are required.

During the planning of new build projects, architects must abide by building regulations for windows which include, amongst others, emergency escape, security and safety. The purpose of the building and the occupants must be considered to ensure that the most appropriate solution is fitted. At Carl F Groupco, we always advise our customers to be well versed on relevant building regulations when working on such projects.


There are three key areas where window restrictors are required by law: schools, healthcare facilities, and care homes. A window restrictor is critical in all these areas for windows above the ground floor. Hospitals and care homes must place the safety of their patients at the forefront, and for these institutions, it is not uncommon to see patients disorientated or mentally unstable and therefore at risk of behaving erratically and dangerously near open windows.

Schools are required by law to restrict windows to an opening of no more than 100mm. In addition to pupil safety, this helps to prevent unwanted behaviour that could become a danger to others, such as throwing items at pedestrians below the window.


There are some instances in which a window restrictor is not required by law, but many still opt for this add on for personal reasons.

Many families in residential homes choose to have this safety addition installed. Children under five have been found to be most at risk of falling out of open windows, and so parents of small children often install these to give themselves peace of mind.

The workplace is also an area where restrictors are not required by law, but strongly recommended. Many employers opt to purchase restrictors to prevent accidents ahead of time. A health and safety assessment will be able to alert employers to the risk of not having a restrictor in place.

What options are available?

Whether required by law or wanted through personal choice, window restrictors come in a range of shapes and styles.


Many window hardware manufacturers produce concealed window restrictors, such as the Res-Lok Concealed Locking Restrictor. The benefits concealed window restrictors provide is that they offer automatic engagement and are more difficult to tamper with. They can also offer the opportunity for windows to be secured open at a specific distance.

Face Fix

Window restrictors that are added to the window frame, such as the CFGLock+ Cable Restrictor or the Res-Lok Surface Fix Restrictor. These additional surface window restrictors are equally as secure as the more concealed or built-in systems. A steel cable encased in rubber provides incredibly strong restriction that cannot be easily broken or worked around. It allows increased airflow whilst ensuring protection at all times.

At Carl F Groupco, as leading distributors of window hardware, including handles, friction stays, remote control systems, and additional safety and security add-ons, we are well placed to advise you on the right window restrictor for you. Get in touch on 01733 393330 or email us at sales@carlfgroupco.co.uk. Alternatively, you can fill out our online enquiry form.

Back to News

More News

Keep In Touch

Contact us for more information on our products, services, and support. Stay up to date with our latest hardware news and connect with our team on Twitter and LinkedIn.