Emergency Power Backup Systems – Overview
Emergency power backup systems are critical components in any life safety or mission-critical infrastructure. They ensure that essential systems, such as fire alarms, emergency lighting, fire-fighting lifts, smoke control systems, and communications remain operational during power outages. These systems form part of the wider strategy for life safety and business continuity, particularly in compliance with UK regulations and standards.
Purpose of Emergency Power Systems
The primary goal of emergency power systems is to provide temporary or uninterrupted power to life safety and essential services during a failure of the normal electrical supply. These systems are designed to operate:
- Instantaneously or within a defined switchover period
- For a duration suited to the building type, risk profile, or regulatory requirement
- Reliably and independently of the main electrical infrastructure
Common Emergency Power Sources
| System Type | Description | Typical Use Cases | Response Time |
|---|---|---|---|
| Diesel Generators | Engine-driven alternators that start automatically during outages. | Hospitals, large commercial buildings, data centers | 10–15 seconds |
| UPS (Uninterruptible Power Supply) | Battery-based systems providing instant power to bridge the gap before generator startup. | IT systems, fire alarms, emergency lighting | 0 milliseconds |
| Battery Backup Systems | Standalone or integrated battery banks dedicated to specific systems. | Fire alarms, emergency lighting, telecoms | Instant or short delay |
| Fire-Fighting Power Supply | Dedicated electrical supply circuits or backup paths for fire-fighting lifts and smoke control systems. | High-rise and commercial premises | As required by design |
Applications in Life Safety
Emergency power systems support a wide range of critical infrastructure, including:
- Fire Detection and Alarm Systems – Continuity of detection, signaling, and alarm during outages.
- Emergency Lighting – Maintains illumination along escape routes for safe evacuation.
- Smoke Control Systems – Ensures smoke extraction or containment operates under emergency conditions.
- Fire-Fighting Lifts and Systems – Allows use by fire services during incidents.
- Communications – Maintains building or site-wide voice and data systems, including public address and emergency phones.
Regulatory Framework and Guidance
In the UK, emergency power systems are influenced by several standards and regulations:
- BS 5839-1 – Requires standby power for fire alarm systems.
- BS EN 1838 / BS 5266-1 – Governs emergency lighting duration and performance.
- BS 8519 – Covers power supplies for life safety and fire-fighting equipment in buildings.
- BS EN 62040 series – Specifies safety and performance of UPS systems.
- Building Regulations (Approved Document B) – Outlines general requirements for fire safety systems, including power continuity.