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5be840 R. Bishop 2025-09-19 20:09:01 1 
# BS 7273-4: Actuation of Release Mechanisms for Doors
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## Overview
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**BS 7273-4:2015 + A2:2023** is the British Standard that governs how **electrically locked or held-open doors on escape routes** must be released in the event of fire or system fault.
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The standard ensures that escape doors controlled by electricity always release **reliably, quickly, and fail-safe**, maintaining the principle of free egress under the **Regulatory Reform (Fire Safety) Order 2005** and related legislation.
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## Scope
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BS 7273-4 applies to:
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* **Electrically locked doors** (maglocks, solenoid bolts, shear locks, etc.)
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* **Electrically held-open doors** (e.g. electromagnetic door retainers)
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* **Doors on escape routes or final exits** where release must be guaranteed
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It does **not** apply to purely mechanical hardware (e.g. un-locked panic bars).
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---
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## Categories of Actuation
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BS 7273-4 defines **three categories of system integrity**, depending on the criticality of the door:
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| Category | Release Conditions | Typical Applications |
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| -------------------- | ------------------------------------------------------------------------------------------------------------------------ | ----------------------------------------- |
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| **A (Highest)** | Must release on fire alarm **and** on virtually any fault (open circuit, short, loss of power, isolation of fire panel). | Final exits, stair cores, high-risk areas |
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| **B (Intermediate)** | Must release on fire alarm plus certain critical faults. | Escape doors on main circulation routes |
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| **C (Basic)** | Must release only on fire alarm. | Lower-risk areas with alternative exits |
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---
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## Manual Release Devices
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Every electrically locked escape door must also have a **local manual means of release**, even if the fire alarm system is interfaced.
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### Acceptable Devices
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* **BS EN 54-11 Type B manual call point (MCP)**
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* Resettable or frangible “break glass” type
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* Provides direct contacts to drop lock power
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* **Emergency Door Release (EDR) unit to BS 7273-4 requirements**
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* Clearly marked green unit labelled *Emergency Door Release*
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* Provides sustained fail-safe release
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### Placement
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* Adjacent to the door on the escape side
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* Height approx. 1.4 m, visible and unobstructed
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* Illuminated where lighting is poor
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### Non-Compliant Devices
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* **Timed auto-reset units** (that re-lock after a delay)
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* **Push-and-hold-only buttons** (release only while held in)
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Both fail because the standard requires **sustained release until reset**.
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---
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## Performance & Timings
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* Door must release within **3 seconds** of actuation (fire, fault, or manual).
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* Release devices must be robust and suitable for repeated operation.
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* Locks must **fail safe** (loss of power releases the door).
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## Integration with Fire Alarm Systems
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* Release mechanisms must be controlled by the **fire detection and alarm system (FDAS)**.
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* Fire alarm interface alone is **not sufficient** — local MCP/EDR still required.
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* Categories A and B require **fault monitoring** of circuits.
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---
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## Panic Bars and Exit Hardware
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**BS EN 1125** (panic bars) and **BS EN 179** (emergency push pads/levers) require that doors open by a **single mechanical action**, regardless of electrical systems.
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### Non-Compliant
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* Maglocks fitted to doors with panic bars or pads:
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* The panic hardware cannot mechanically override the lock.
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* Escape depends on electrical release, breaching EN 1125/179.
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### Compliant
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* **Electrified panic hardware** tested and CE-marked to EN 1125/179:
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* Push bar always mechanically releases the door.
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* Electronic control is supplementary (e.g. latch retraction for access).
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* **Mechanical escape doors kept separate from access-controlled doors**.
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---
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## Maintenance
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* All doors, release devices, and interfaces must be tested during **routine FDAS maintenance** (BS 5839-1).
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* MCP/EDR units should be checked regularly for correct operation.
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* Documentation must record:
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* Category of actuation per door
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* Wiring and interfaces
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* Commissioning/test results
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## Key Points
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* BS 7273-4 ensures electrically controlled escape doors always release fail-safe.
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* Manual local release (green MCP/EDR) is always required.
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* Auto-reset or push-and-hold devices are non-compliant.
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* Panic bars must provide a **mechanical override** — maglocks across them are not acceptable.
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* Compliance requires correct design, installation, testing, and maintenance.
f8e48f R. Bishop 2025-09-19 20:10:12 120
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## Compliance Quick Reference – Escape Door Locking & Release
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| Door Setup | Compliant? | Notes |
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| ------------------------------------------------------------------------------ | --------------- | ----------------------------------------------------------------------------------------- |
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| **Electrically locked door with fire alarm interface only (no local MCP/EDR)** | ❌ Non-compliant | Fire alarm must not be the *only* release method. Local MCP/EDR always required. |
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| **Electrically locked door with fire alarm interface + local MCP/EDR** | ✅ Compliant | Meets BS 7273-4 when designed to correct Category (A/B/C). |
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| **Door with green “push-to-exit” button only (hold-to-run)** | ❌ Non-compliant | Release must be sustained until reset, not dependent on user holding button. |
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| **Door with timed auto-reset EDR** | ❌ Non-compliant | Locks must stay released until deliberate reset; auto re-locking is unsafe. |
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| **Maglock on door with panic bar/push pad** | ❌ Non-compliant | Panic hardware must always mechanically override; maglock prevents single-action escape. |
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| **Electrified panic hardware (EN 1125/179 tested & CE-marked)** | ✅ Compliant | Panic bar always opens door mechanically; electrification is for access control only. |
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| **Purely mechanical panic bar/push pad (no maglock, no electronics)** | ✅ Compliant | Meets EN 1125/179; always provides free mechanical escape. |
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| **Electrically held-open fire door with automatic release on alarm** | ✅ Compliant | Provided it releases within 3 seconds and has MCP nearby if also used as an escape route. |
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**Reminder:** Under BS 7273-4, the golden rule is **fail-safe, sustained release with local manual override**. Anything that re-locks automatically or prevents mechanical escape is non-compliant.