Section Env-Or 305.11 - Overfill Protection(a) Unless excluded under (e), below, each AST system shall be equipped with a gauge or other automated measuring device that accurately shows the level of product in the tank and is accessible to the transfer operator prior to initiating the transfer.(b) Each AST system shall have a high level warning alarm that:(1) Operates independently of the gauge required by (a), above; and(2) Is both audible and visible to the transfer operator.(c) The high level warning alarm required by (b), above shall be activated when: (1) The tank is filled to 90 percent of the total capacity of the tank, for tanks with a storage capacity of 12,000 gallons or less; or(2) The tank is filled to 3 percent less than the calculated maximum safe fill height, for tanks with a storage capacity of greater than 12,000 gallons.(d) In any AST system having an oil storage capacity of 660 gallons or less, a vent alarm may be used in lieu of the high level alarm if:(1) The delivery hose fits tightly to the fill pipe;(2) The opening for the vent pipe is located no more than 10 feet from the fill pipe connection and is visible to the transfer operator; and(3) The vent alarm is audible to the transfer operator.(e) The requirements of this section shall not apply to the following containers when not connected to other containers:(1) Drums less than 60 gallons in size; and(2) Intermediate bulk containers or overpack drums as identified in NFPA 30.N.H. Admin. Code § Env-Or 305.11
(See Revision Note at chapter heading for Env-Or 300) #10487, eff 2-7-14