Comment on Day Tank Sizing

Dan: Your posting on day tank capacity sizing was right on target. I have seen one more conservative interpretation that reflects back to NFPA-70, 700-12(b)(2) where an "on premise" fuel storage capacity of 2 hours minimum is called out.

I use this guideline to size day tank capacity to 2 hours beyond the low-level alarm switch level - typically set for 65% of tank level. This will give an operator time to respond to a problem with the fuel system and either correct it or come up with a work-around.

This came about from an inspector insisting that the NFPA-110 class for an EPSS was a requirement additional to the NFPA-70 2 hour minimum. In this case, it made such good sense I adopted the rational.

Regards,
Andy Lehing
Riggs Power Solutions