Section 658-109-10 - Oil Supply Tanks1.Inside Tank FabricationA. Rectangular built-in place tanks shall be fabricated using one-quarter (1/14) inch minimum thick steel sheets reinforced on maximum twenty-four (24) inch centers. Tank bottoms shall be supported on twelve (12) inch wide non-combustible piers, to a height of eight (8) inches above the floor. All welding shall be performed by a welder. Tanks shall be designed by a registered engineer who shall observe the tank under 5 PSI test and certify to it being tight under this test. 2.ManholesA. Manholes, sixteen (16) inches in diameter or larger, shall be installed in the top of all tanks of 5,000 gallons or more.B. Manholes provided in 5,000 gallons supply tanks shall be liquid tight when installed inside of a structure.C. Manholes, when required for outside use, may take the form of a floating lifter roof or weak roof-to-shell seam or other approved pressure relieving construction.3.Clearances. All fuel oil supply tanks must be a minimum of five (5) feet from any gas and/or solid fuel burning appliance.02-658 C.M.R. ch. 109, § 10