Is BS 5839 a legal requirement?
A clear explanation of the legal status of BS 5839, how it relates to fire safety legislation, and what the practical consequences are of departing from it — by a fire engineer with 30 years of experience.
BS 5839 is not law. It is a British Standard — a document published by the BSI that defines accepted best practice. You cannot be prosecuted for failing to follow BS 5839 in the same way you can be prosecuted for breaching the Fire Safety Order. But the distinction matters far less than people assume, and treating BS 5839 as optional is a serious mistake.
The Status of BS 5839
BS 5839 — in both its Part 1 (non-domestic) and Part 6 (domestic) editions — is a British Standard, not legislation. It is published by the British Standards Institution and developed by committees of industry experts. It represents the consensus view of what constitutes a properly designed, installed, and maintained fire alarm system.
The law governing fire safety in non-domestic premises is the Regulatory Reform (Fire Safety) Order 2005. The Order requires the responsible person to provide appropriate fire detection and warning systems, but it does not name BS 5839 or require compliance with it specifically.
Why it matters anyway
The Practical Reality
The fact that BS 5839 is not law does not mean it can safely be ignored. The consequences of departing from it are real and significant:
| Area | Consequence of departing from BS 5839 |
|---|---|
| Legal compliance | BS 5839 is the primary benchmark used by fire inspectors to assess whether the Fire Safety Order’s requirements have been met. A system that departs from it must demonstrate an equivalent level of protection — which is difficult to argue without the standard as a baseline |
| Insurance | Insurers frequently require fire alarm systems to be installed and maintained to BS 5839 as a condition of cover. A system that falls short may invalidate a claim following a fire |
| Enforcement action | Where a fire inspector identifies deficiencies, enforcement notices will typically reference BS 5839 as the standard to be met. Non-compliance with BS 5839 is effectively non-compliance with the enforcing authority’s expectations |
| Civil liability | In the event of a fire where persons are injured or killed, departure from BS 5839 would be relevant evidence in civil and criminal proceedings. Courts regard the standard as the measure of what a competent person would have done |
| Certification | Third-party certification schemes for fire alarm contractors (such as BAFE SP203-1) are based on compliance with BS 5839. A system installed by a certified contractor carries the implicit assurance of meeting the standard |
The deemed to satisfy principle
Compliance with BS 5839 and the Law
While BS 5839 is not itself law, compliance with it creates what is sometimes called a “deemed to satisfy” position. A responsible person who installs and maintains a fire alarm system in accordance with BS 5839-1 can be confident that they have met the fire detection and warning requirements of the Fire Safety Order. They do not need to separately justify every design decision — compliance with the standard is the justification.
A responsible person who chooses not to follow BS 5839 does not automatically breach the law — but they take on the burden of demonstrating that their alternative approach provides an equivalent level of protection. In practice, this is very difficult to establish and is rarely a position any competent professional would recommend.
The Practical Advice
For any commercial premises, specifying a fire alarm system to BS 5839-1 and having it installed by a BAFE-certified contractor is the clearest, most defensible way to meet the legal obligation under the Fire Safety Order. Any departure from the standard should be documented, justified, and agreed with the fire risk assessor. “We didn’t know about BS 5839” is not a defence that will carry weight with an enforcing authority or a court.
Where BS 5839 is referenced in law
When BS 5839 Becomes Directly Referenced
Although BS 5839 is not directly cited in the Fire Safety Order, it is referenced in several other legal and quasi-legal contexts:
Building Regulations (Approved Document B) — the fire safety guidance for new construction references BS 5839 in the context of fire alarm and detection requirements for new buildings. For new construction, following Approved Document B’s references to BS 5839 is effectively mandatory for building control approval.
HMO licensing conditions — local authorities licensing houses in multiple occupation will typically specify BS 5839-6 grades and categories as licence conditions, making compliance directly enforceable via the licensing regime.
Contractual requirements — public sector contracts, PFI agreements, and many commercial leases specify BS 5839 compliance directly, making it a contractual as well as a regulatory obligation.
Common questions
Frequently Asked Questions
Not directly — there is no offence of “failing to comply with BS 5839”. However, you can be prosecuted for failing to meet the requirements of the Fire Safety Order, and a system that falls significantly short of BS 5839 will almost certainly be found to fail the Order’s requirements too. The standard and the law are closely aligned in practice even if they are legally distinct.
There is no general legal requirement to upgrade an existing system when a new edition of BS 5839 is published. However, fire inspectors and insurers will assess your system against the current version of the standard. If a periodic review identifies that your system falls significantly short of current requirements — particularly on safety-critical issues — upgrading will likely be recommended. Significant changes of use or occupancy are also triggers to bring the system up to the current standard.