Which emergency sound standard applies to my building?
Which standard applies depends on what the system is for, not what it is called. A spoken fire evacuation message triggered by the fire alarm is a voice alarm (BS 5839-8). Two-way speech from refuges or for firefighters is an emergency voice communication system (BS 5839-9). Sounders that firefighters use to evacuate floors of a block of flats are an evacuation alert system (BS 8629). Large venues add BS 7827, and non-fire emergencies such as lockdown fall under BS EN 50849.
People search for “PAVA regulations” or “voice alarm requirements” and find five different British Standards, each with its own scope. They overlap less than they appear to. The quickest way to find the right one is to ask what the system is for.
The short answer
| What the system does | What it is called | Standard |
|---|---|---|
| Plays a spoken evacuation (and often alert) message automatically when the fire alarm operates | Voice Alarm System (VAS), often a Public Address Voice Alarm (PAVA) system | BS 5839-8:2023 |
| Lets people in disabled refuges, or firefighters and stewards, talk two ways with a control point | Emergency Voice Communication System (EVCS): refuge intercoms and fire telephones | BS 5839-9:2021 |
| Lets the fire and rescue service sound alarms in chosen floors of a block of flats to change from “stay put” to evacuation | Evacuation Alert System (EAS) | BS 8629:2019+A1:2023 |
| Covers emergency broadcast across a stadium, arena, large transport hub or shopping centre | Emergency Sound System (ESS) for a large venue | BS 7827:2019, which allocates each zone to BS 5839-8 or BS EN 50849 |
| Broadcasts instructions for emergencies other than fire: lockdown, invacuation, crowd management, process or gas alarms | Emergency sound system for non-fire purposes | BS EN 50849:2017 |
Most buildings need only one of these. Many larger buildings have two or three: an office tower with a voice alarm and refuge intercoms, for example, or a stadium with all of them.
Five questions that settle it
1. Is the message triggered by the fire alarm?
If the system broadcasts a recorded evacuation message when the fire detection and fire alarm system operates, it is a voice alarm system and BS 5839-8 is the code of practice for its design, installation, commissioning and maintenance. Its scope is voice alarm systems connected to a fire detection and fire alarm system; a system operated only by hand, or one used for non-fire emergencies, falls outside it (BS 5839-8:2023, Clause 1).
Whether a building needs a voice alarm at all is a fire strategy decision, not something BS 5839-8 decides. Voice alarm is typically called for where people are unfamiliar with the building, where evacuation is phased or staged, or where a bell or sounder alone would not get people moving. BS 9999 is the usual reference for that decision.
2. Do people need to talk, not just listen?
A voice alarm talks to people. An emergency voice communication system lets them talk back. BS 5839-9 covers fire telephones used by firefighters and stewards, and the two-way intercoms in disabled refuges where someone waits for assisted evacuation. Fire safety guidance for buildings other than dwellings, including Approved Document B Volume 2 in England and BS 9999, expects a refuge to have a way for the person waiting there to call for help, which in practice is an EVCS. Approved Document B Volume 1, which covers flats and houses, does not make the same recommendation.
3. Is it a block of flats, and is the system for the fire and rescue service?
An evacuation alert system is not a fire alarm. It has no detectors and no call points. It gives the fire and rescue service a secure control panel at the entrance, with one switch per floor, so they can sound alert devices in the flats on chosen floors if a “stay put” strategy has to change during a fire. BS 8629 is the code of practice. In England, Approved Document B was amended in December 2022 to recommend an evacuation alert system in new blocks of flats with a top storey more than 18 m above ground level (Approved Document B Volume 1, paragraph 15.17); Scotland introduced a similar recommendation in 2019. See our guide to evacuation alert systems.
4. Is it a large or complex venue?
Stadia, arenas, large transport hubs and shopping centres are the territory of BS 7827. It sits above the other two broadcast standards rather than competing with them: it recommends a risk assessment that divides the venue into voice alarm zones and emergency sound system zones, then applies BS 5839-8 or BS EN 50849 to each (BS 7827:2019, Clauses 4.1 and 4.2). Sports grounds also have the Guide to Safety at Sports Grounds (the Green Guide), which a local authority safety certificate may call up.
5. Is the emergency something other than fire?
Lockdown, invacuation (moving people inside, away from a threat outside), crowd management, and industrial process or gas alarms are covered by BS EN 50849. Its scope excludes systems used for fire evacuation, whether or not they are connected to fire detection (BS EN 50849:2017, Clause 1). The Terrorism (Protection of Premises) Act 2025, known as Martyn’s Law, is making procedures for this kind of event a duty for many public venues, which is bringing BS EN 50849 into more conversations.
The supporting standards
The five codes above refer to others for specific jobs. You will see these in specifications and submittals:
- BS EN 54-16 covers the control and indicating equipment of a voice alarm (the VACIE). BS EN 54-24 covers voice alarm loudspeakers. These are product standards: they apply to the equipment you buy, not to the system design.
- BS EN IEC 60268-16 is the method for measuring speech intelligibility as a Speech Transmission Index (STI). BS 5839-8 uses it when intelligibility is measured rather than judged by listening (BS 5839-8:2023, Clause 20.3).
- BS 5839-1 covers the fire detection and fire alarm system that triggers a voice alarm.
- BS 7671 (the IET Wiring Regulations) covers the electrical installation the systems connect to.
Codes of practice, not laws
All five main standards are codes of practice. They recommend (“should”); they do not require. A recommendation becomes an obligation when something else calls it up: the fire strategy, a specification or contract, building regulations guidance, or a safety certificate. Each standard also allows departures that are agreed and recorded as variations, as long as they can be justified.
What is a legal duty is keeping fire safety systems working. In England and Wales, the Regulatory Reform (Fire Safety) Order 2005 requires the responsible person to make sure fire safety equipment is subject to a suitable system of maintenance and kept in efficient working order and good repair (Article 17). For a voice alarm, the maintenance clauses of BS 5839-8 are the normal way to show that. See what a voice alarm service visit should cover.
More than one system in the same building
Where a building has several systems, each standard covers its own system and they meet at defined interfaces. Two examples of where the boundaries matter:
- Refuges. BS 5839-8 recommends that voice alarm loudspeakers are not sited close to refuges, so that a person using the refuge intercom can hear and be heard (BS 5839-8:2023, Clause 11.6).
- Mixed-use buildings. A residential tower above a shopping centre might have an evacuation alert system in the flats and a voice alarm in the retail floors. They are separate systems with separate standards, separate certificates and often separate maintainers.
If you are not sure which systems you have, the system logbook and the handover certificates should say. Our glossary explains the terms you will find in them.
This guide is general guidance written in our own words, not a design or a compliance assessment for any particular building. Clause numbers are given so you can check the standard itself, which is available from BSI. Spotted something wrong or out of date? Email contactus@proaudium.com.