Hi

Do small boiler rooms and server rooms have to have automatic fire detection? Is there anything written down saying it’s a must or it’s strongly advised, if so where? 

Thanks

Not automatically no. Most premises have detection over and above what is legally needed for life safety with most buildings actually only requiring manual call points.

Where detection is required for life safety it normally has to be tiered with each tier including the cover of a previous tier. You start at L4 covering escape routes only, then go to L3 which is L4 (escape routes) with the addition of cover to rooms opening onto them . The next tier is L2 which is L3 cover (escape rooms plus rooms adjoining) plus defined high risk areas. These areas are specific to a particular building & risks, so in some premises an L2 system would include the boiler room and in others it wouldn't. The top tier is L1 which is coverage to virtually everywhere in a building.

A lot of detection is for property protection (known as P systems) and this is often why areas such as server rooms are covered - their location is such that a fire here wouldn't be a life safety risk without the earlier detection (as a person or an escape route detector would catch the fire before it was such a risk) but any delay would be damaging to business continuity. You could say the same for a boiler room, which being an area of special fire risk would often have enhanced structural fire protection such that a fire would be contained such as not to threaten life, but totally destroyed boilers are expensive to replace and may affect the ability to comfortably use the premises.

The various sector specific fire safety guides on the gov.uk website, plus the fire alarm standard BS5839-1 give pointers for existing buildings. BS5839-1, along with Approved Document B to the Building Regulations and BS9999 give guidance for the design of new builds.

So in summary it's not always a must (especially for servers). A lot depends on the layout and usage of the premises - a traditionally built office would usually need neither covered, a care home would need both, an office using a fire engineered solution to deviate from traditional building regulations guidance would also usually need both - it's all down to risk assessment.

(There is an L5 type of coverage which is for a specific risk or fire safety purpose and can involve anything from a single detector to hundreds, but  I didn't weant to complicate things for you!)