Compliance
BS EN 12845, in plain English
BS EN 12845 is the European standard for the design, installation and maintenance of fixed fire sprinkler systems in commercial and industrial buildings. It is the document that sets the weekly, monthly, quarterly, half-yearly and annual routines a UK sprinkler system has to be kept to.
BS EN 12845 is the standard that governs fixed fire sprinkler systems in commercial and industrial buildings in the UK: how they are designed, how they are installed, how the water supply is proved, and how they are maintained for the rest of their working life.
If you own or manage a building with sprinklers, the last of those is the part that reaches you. The standard is where the weekly, monthly, quarterly, half-yearly and annual routines come from, and it is what a fire risk assessor, an insurer or an enforcing officer will measure your records against.
What the standard actually covers
Four things, in the order they happen to a system.
Hazard classification. Before anything is designed, the building is classified by what is in it and how it burns. Light Hazard, Ordinary Hazard groups 1 to 4, and High Hazard for process and storage risks. The class decides the design density, the assumed area of operation, and therefore the size of everything downstream. A warehouse that changes what it stores can quietly move hazard class without anyone redesigning the system, and that is one of the most consequential things that happens to a sprinkler installation.
Design and installation. Head spacing, pipe sizing, the number and arrangement of control valve sets, and the rules for where sprinklers may and may not be omitted.
Water supplies. The standard is unusually strict here, because a sprinkler system is only as good as the water behind it. Town main, tank and pump, or a combination, each with a required duration and pressure for the hazard class.
Maintenance. The routines below, which is where most readers of this page actually are.
The maintenance regime
This is the part worth knowing by heart, because a gap in it is a gap in your records.
| Interval | What happens |
|---|---|
| Weekly | Water and air pressure gauges read and logged, trace heating and tank levels checked, and the alarm test valve operated to prove the gong or the pressure switch |
| Monthly | Water levels and the condition of any suction tank checked, pump fuel and battery condition where applicable |
| Quarterly | Flow switch and alarm testing, and a check of the pump starting arrangements |
| Half-yearly | An interim service, including the alarm and the dry pipe arrangements where fitted |
| Annually | The full service: control valve sets stripped, cleaned and reassembled, pumps proved under flow against their curve, water supply proved, and the whole installation inspected against the design |
The weekly checks stay with the responsible person unless you contract them out. That surprises people, and it is the single most common gap we find: the annual service is in place, the weekly log is empty or stops eighteen months ago. The service is what a contractor does. The log is what the building does, and it is the one an inspector reads first.
The detail of what each visit covers is in our guide to sprinkler servicing intervals.
Hazard classes, and why they matter to you
You do not need to be able to classify a building. You do need to know that the classification exists and that it was made once, on the day the system was designed, against what the building held then.
Three things move a building up a hazard class without anybody noticing:
- Racking gets taller. Storage height is a direct input to the classification.
- What is stored changes. Plastics, aerosols and foam products burn very differently from cardboard boxes.
- The layout changes. Racking added under a section designed for open floor changes the water that reaches the fire.
If any of those has happened since the system went in, the honest answer is that the design should be reviewed, not that the annual service will catch it. It will not: a service proves the system works as designed, not that the design still fits the building.
What an insurer is actually asking for
Insurers rarely ask “is it to BS EN 12845”. They ask for the evidence that follows from it: a current service certificate naming the standard, a complete weekly log, a pump test record showing performance under flow rather than a start, and a defect list with dates against it.
That last one matters more than people expect. A defect list with dates showing things being found and fixed is stronger evidence than a clean sheet, because a clean sheet on a twenty-year-old installation reads as an inspection nobody did. What we look for at renewal is covered in what your insurer wants to see.
Where BS EN 12845 stops
Two boundaries worth knowing.
It does not cover residential and domestic systems, which are BS 9251. Different design philosophy, different water supply expectations, different heads. A mixed building can have both, and they are serviced to different regimes. Our guide on sprinklers in blocks of flats covers where the line falls.
It does not cover dry and wet risers, which are BS 9990 and are not sprinkler systems at all, however similar the red pipe looks. Buildings routinely have both, on separate certificates, and we still meet managers who believe one covers the other.
The practical version
If you take three things from the standard:
- The weekly log is yours, and it is the first thing anyone asks for.
- The annual service must include the pump proved under flow, not started and signed off. A pump that starts and cannot deliver its duty is a pump that passes a bad test.
- The hazard class was set once. If the building has changed, say so, and have the design looked at rather than assuming the service covers it.
If you want that regime run properly against the standard rather than against a template, that is sprinkler servicing.
This work, on our sites
Questions we get asked
Is BS EN 12845 a legal requirement?
Not directly. The law is the Regulatory Reform (Fire Safety) Order 2005, which requires fire safety measures to be maintained in efficient working order. BS EN 12845 is how that duty is discharged for a sprinkler system: it is the recognised standard, insurers write it into policies, and a fire risk assessor will measure your records against it.
What is the difference between BS EN 12845 and the LPC Rules?
The LPC Rules are BS EN 12845 with a set of UK technical bulletins bolted on, published by the Fire Protection Association. Where an insurer specifies the LPC Rules they are asking for the standard plus those bulletins, which tighten several requirements. If your policy names them, the difference is not academic.
Does BS EN 12845 cover flats and houses?
No. Residential and domestic systems fall under BS 9251, which is a different design philosophy: life safety with a smaller water supply, rather than property protection. A block of flats may have both, with BS 9251 in the dwellings and BS EN 12845 in a basement car park.
Where can I get a copy of the standard?
From BSI, and it is a paid document. There is no free legitimate download, and the copies circulating on file-sharing sites are usually superseded editions, which in this trade is worse than having none. If you need to check a clause, ask your contractor to quote it and cite the edition.
Where this comes from
- BS EN 12845Fixed firefighting systems. Automatic sprinkler systems. Design, installation and maintenance
The standard commercial and industrial sprinkler systems are designed, installed and maintained to. It sets the weekly, monthly, quarterly and annual routines.
BSI
- BS 9251Fire sprinkler systems for domestic and residential occupancies. Code of practice
The residential equivalent: blocks of flats, care homes, student accommodation and houses.
BSI
- LPC RulesLPC Rules for Automatic Sprinkler Installations, incorporating BS EN 12845
The insurer-facing ruleset that sits alongside BS EN 12845. Part 1 is the standard itself; the technical bulletins in Part 2 are what an insurer means by property protection.
Fire Protection Association
British Standards are copyright documents and most are bought rather than read free. We hold the ones we work to. If you need to know what one of them says about your building, ask us rather than buying it.