Diesel Fuel Day Tanks

[joan271273]

I have a four (4) 2MW diesel gen-sets that have a small 50 gallon day tank that is connected to a 4,000 gallon main tank. The question has come up by the Caterpillar on site technician that the overflow port of the day tank should be connected to the main tank as a return line. This connection is what makes the system safe in the event of failure of any sensor within the day tank.

Is the on board day tank a Code Requirement

 

[pmover]

while i'm not at my office and relying on my memory, i recommend investigating the NFPA Stds for your application. i believe the nfpa std is 30(?).

i do not remember any piping system you described as being a requirement. this does not mean that the responsible engineer should not consider installing such a system. the responsible engr should investigate all scenarios (normal operating and otherwise) and design accordingly.

good luck!
-pmover

 

[DavidCR]

I think NFPA 37 would be useful.

 

[joan271273]

I do not have available either NFPA standard, can someone advise if this overflow piping back to the main tank ,is a Code requirement

 

[alehman]

NFPA 37 requires an overflow line for tanks where fuel is pumped into the tank. If the day tank is higher in elevation than the main tank, this may be a gravity line. If it is the same or lower elevation, it must be pumped.

 

[WoodrowJWeen]

Having a return line is a standard practice. The return line allows excess fuel to be returned from the day tank to the main tank in the event that the supply transfer pump does not shut off.