I have a diesel generator on the ground floor, with a fuel tank one floor below in the basement. The only mitigation of suppression is via a fixed foam inlet from outside which would direct the firefighters foam branch above the diesel fuel tank to the floor below the engine. 

 The building is full of offices. Should a fixed integrated system be installed or is this a generic system??

 

Does the building have oil fired central heating and is the fuel tank located in the basement? Are you sure the generator deisel tank is located in the basement and what does your fire risk assessment say about this situation?

No oil, heating powered by gas boilers. 

Generator located on ground floor. There is a day fuel tank in the same room. If there is a fire alarm the valve drops and sends the fuel to the diesel tank in the basement. 

 The basement has a foam riser from outside and the outlet is positioned above the fuel tank. So firefighters can plug into it if needed. 

However, I consider the generator a medium fire risk as it is well maintained and if a fire existed it would dump the fuel away from the engine. I believe that if a supression system was installed as well, this would mitigate any damage from an early stage.

That's unusual, you normally get valve shutoff, but not fuel diversion. How old is the original building as basement fuel oil tanks with foam inlets are shouting pre-1960's office block.

You've got more precautions than most generator set ups in buildings so I wouldn't be too concerned.

 

Anthony Buck
Alcumus HSE
BAFE SP205 Third Party Accredited Fire Risk Assessors

50's-60's

Would you recommend a suppression system in the diesel room??

All that diesel fuel being in the building.

Not for life safety. It could be a business continuity issue warranting such provision.

I can't comment definitively without seeing the site, the tanks and building  structure.