Does an unvented cylinder for hot water need to be behind a fire door with a smoke sensor?

[Guest JamesJames]

I am developing an HMO with a Grade A LD2 fire alarm system, and I am installing an unvented cylinder for the hot water system in a non-ensuite bathroom. 

Does that mean I need to put a fire door on that bathroom and also have a smoke sensor in that bathroom?

[AnthonyB]

I've only usually seen this required where a heating boiler is in the bathroom, not a simple hot water cylinder.