"Auxiliary tank" means a day tank installed in the supply piping between a heating oil burning device and the UST that supplies it, is an integral component of the piping system, and is a UL 443 tank not exceeding 60 gallons in capacity.
N.H. Admin. Code § Env-Or 402.04
(See Revision Note at chapter heading for Env-Or 400) #10393, eff 9-1-13