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JUL 28 2014 <br />ENVIRONMENTAL HEALTH <br />11.5.1 Siphon tubes maybe added to the fittings specified in sections 11.2 and 11-P)EPARTMENT <br />siphon tube will allow these fittings, when used as drainage fittings, to provide better tank <br />drainage. <br />11.7 Vents <br />11.7.1 Each tank must be properly vented for the type of material and flow rates <br />expected. Vents must comply with OSHA 1910.106 (f) (2) (iii) or other accepted standard. <br />All tanks must be vented for atmospheric pressure as well as any pressure created by filling <br />and emptying the tank. Some applications may require a sealed tank with a vent line going <br />to a scrubber system for proper chemical safety. Venting equipment should be sized to <br />limit pressure or vacuum in the tank to a maximum of 1/2" of water column (0.02 psi). U - <br />Vents are offered in sizes from 1 in. to 6 in. with or without mesh insect screening. U -Vents <br />with mesh screening may require additional sizing due to reduced air -flow rates. Consult <br />the manufacturer for necessary venting and placement information. <br />11.7.2 All u -vents shall be constructed of PVC or other specified materials. <br />11.7.3. When a tank is being filled from a pressurized tanker truck or railcar steps need to <br />be taken to avoid pressurizing the tank. The tank may require a secondary surge protection <br />lid to avoid any pressure build up. The surge protection lid is to be a 14" or 18" hinged and <br />be design that it is self-closing. <br />11.8 Flange Adapters <br />11.8.1 Flange adapters maybe purchased as optional equipment to adapt threaded or <br />socket fitting outlets to 150 Ib. flange connections for connection to piping system <br />components. Flange adapters are available in PVC. Flange adapter construction shall <br />utilize schedule 80 components in sizes ranging from %" to 8" depending on material <br />required. <br />11.9 Fittings - Self -Aligning Threaded Bulkhead <br />11.9.1 Self -Aligning fittings are available for installation in vapor phase applications on <br />curved surfaces depending on the spherical dome radius and the placement of the fitting on <br />the tank dome. Fittings must be placed away from tank radius'. Consult SII for placement <br />questions. The maximum allowable size for self -aligning fittings placed on a spherical <br />section of the tank is shown below. <br />Tank Diameter Maximum Fitting Size <br />Allowable <br />45 in. — 48 in. 2 in. <br />64 in. —142 in. 3 in. <br />Tank thickness and fitting angle may need to be considered for self -aligning fitting <br />placement. The maximum thickness and installation angles for each fitting size are shown <br />below. <br />Fitting Size <br />Maximum Angle <br />Maximum Thickness <br />1 in. <br />27 degrees <br />1.000 in. <br />2 in. <br />25 degrees <br />0.750 in. <br />3 in. <br />20 degrees <br />1.000 in. <br />11.9.2 The self -aligning fittings shall be constructed of PVC or CPVC. Gaskets shall be a <br />minimum of 1/4" thickness and constructed of 40-50 durometer EPDM, 60-70 durometer <br />Viton•, or other specified material. <br />11.10 Flexible Connections <br />11.10.1 All tank fitting attachments shall be equipped with flexible couplers or other <br />movement provisions provided by the tank customer. The tank will deflect based upon tank <br />