In multi-storey and multi-residential buildings, windows can present two competing risks: they are a common cause of falls — especially among children and vulnerable individuals — yet are often relied upon as escape routes during a fire. Specifiers must ensure that windows remain both safe in everyday use and rapidly openable in an emergency.
This is where the correct choice of window restrictor becomes critical. Titon’s new Key-Releasable Restrictor provides a robust solution for environments where safety, security, ventilation, and access must all be carefully balanced.
A window restrictor is a hardware device designed to limit the opening size of a window sash to reduce the risk of falls from height. They are an essential safety measure in:
Several serious incidents in care homes and clinical environments have involved vulnerable residents defeating standard restrictors. NHS England guidance highlights that ordinary domestic restrictors are not sufficient in these higher-risk settings.
Health Building Note 00-10 Part D states:
“The opening should be restricted to 100 mm or less. Window restrictors should only be disengaged using a special tool or key”
Restrictors must therefore be tamper-resistant and unlockable only by authorised personnel.
Approved Document K requires restrictors to be fitted on windows in multi-floored dwellings and institutions, where there is a particular risk of falling from heights.
Where a fall risk exists above ground floor level:
“Provide suitable opening limiters to restrain the window sufficiently to prevent such falls.”
This typically means restricting the opening to approximately 100 mm.
Approved Document B says that where windows form part of escape routes, fixed restrictors cannot be used if they delay or prevent egress.
Escape windows should be openable without undue difficulty so that in the event of a fire, occupants can exit quickly.
This allows suitable override mechanisms when escape is required.
Before comparing restrictor types, establish whether the window is part of a fire escape route.
This single check will remove most specification ambiguity and help avoid solutions that are mechanically robust, but operationally unsafe or non‑compliant once the building is occupied.
Fixed restrictors permanently limit opening and cannot be easily overridden without tools. They are selected where fall prevention is the overriding priority and full sash opening is not required in normal operation.
Best for: Highest-risk fall-prevention environments
✔ Maximum protection
✘ Not suitable for escape windows
✘ Can hinder cleaning access
Automatically engaging restrictors provide restricted opening during everyday use, then allow escape‑appropriate override without a key, while re‑engaging automatically when the window is closed.
Best for: Mixed-use residential — HMOs, student living, hotels
✔ Auto-reengaging safety
✔ Keyless, child-resistant override for escape
✘ Not secure enough in highly vulnerable settings
Key‑releasable restrictors limit opening during everyday use, then allow full opening by authorised users using a dedicated key. This is most useful where the operational reality includes controlled supervision, routine cleaning access, or maintenance access, and where tamper resistance is a priority.
Best for: Care, clinical, SEN, supervised settings where the key is securely managed
✔ Prevents resident tampering
✔ Controlled full-open access for authorised users
✔ Ideal where cleaning access is frequently required
The Titon Key Releasable Restrictor is a purpose-designed safety solution that limits everyday window opening to ≤ 100 mm, helping comply with HBN 00-10 and Approved Document K. It can be temporarily de-restricted using a dedicated key to provide full access for cleaning, maintenance or controlled supervision.
When selecting restrictors, ensure:
✔ A written risk assessment is in place
✔ Escape routes remain rapid and unobstructed
✔ The chosen restrictor has proven mechanical performance
✔ A secure key-management procedure is implemented
✔ Planned inspections are included in maintenance schedules
Where windows form part of an escape route, the suitability of the restrictor must be confirmed
by the duty-holder / fire safety adviser / building control body.
Following this approach helps ensure defensible, auditable compliance.
Every project is unique — and so is its safety risk profile. Where fall-prevention is a critical requirement and controlled access to full window openings is necessary, Titon’s Key-Releasable Restrictor delivers a compliant, practical and secure solution.
Our technical team can help you select the correct restrictor for each window type —including drawings, performance data and installation guidance.
Contact Titon’s specialists today for expert assistance.