California Code of Regulations › Title 8 - Industrial Relations › Division 1 - Department of Industrial Relations › Chapter 4 - Division of Industrial Safety › Subchapter 7 - General Industry Safety Orders › Group 20 - Flammable Liquids, Gases and Vapors › Article 145 - Tank Storage › Section 5592 - Normal Venting for Aboveground Tanks

Current through Register 2024 Notice Reg. No. 28, July 12, 2024
(a) Atmospheric storage tanks shall be
						adequately vented to prevent the development of vacuum or pressure sufficient
						to distort the roof of a cone roof tank or exceeding the design pressure in the
						case of other atmospheric tanks, as a result of filling or emptying, and
						atmospheric temperature changes.
(b) Normal vents shall be sized either in
						accordance with the American Petroleum Institute Standard No. 2000, Venting
						Atmospheric and Low-Pressure Storage Tanks, 1968, or other accepted standard,
						or shall be at least as large as the filling or withdrawal connection,
						whichever is larger but in no case less than 1 ¼ -inch nominal inside
						diameter.
(c) Low-pressure tanks
						and pressure vessels shall be adequately vented to prevent development of
						pressure or vacuum, as a result of filling or emptying and atmospheric
						temperature changes, from exceeding the design pressure of the tank or vessel.
						Protection shall also be provided to prevent overpressure from any pump
						discharging into the tank or vessel when the pump discharge pressure can exceed
						the design pressure of the tank or vessel.
(d) If any tank or pressure vessel has more
						than one fill or withdrawal connection and simultaneous filling or withdrawal
						can be made, the vent size shall be based on the maximum anticipated
						simultaneous flow.
(e) The outlet
						of all vents and vent drains on tanks equipped with venting to permit pressures
						exceeding 2.5 psig shall be arranged to discharge in such a way as to prevent
						localized overheating of or flame impingement on any part of the tank, in the
						event vapors from such vents are ignited.
(f) Tanks and pressure vessels storing
						Category 1 flammable liquids shall be equipped with venting devices which shall
						be normally closed except when venting to pressure or vacuum conditions. Tanks
						and pressure vessels storing Category 2 flammable liquids and Category 3
						flammable liquids with a flashpoint below 100 °F (37.8 °C) shall be
						equipped with venting devices which shall be normally closed except when
						venting under pressure or vacuum conditions, or with approved flame arresters.
EXCEPTION: Tanks of 3,000 bbls. capacity or less
						  containing crude petroleum in crude-producing areas; and, outside aboveground
						  atmospheric tanks under 1,000 gallons capacity containing other than Category 1
						  flammable liquids may have open vents. (See Section
						  5594(b).)
(g) Flame arresters or venting devices
						required in (f) may be omitted for Category 2 flammable liquids and Category 3
						flammable liquids with a flashpoint below 100 °F (37.8 °C) where
						conditions are such that their use may, in case of obstruction, result in tank
						damage. Liquid properties justifying the omission of such devices include, but
						are not limited to, condensation, corrosiveness, crystallization,
						polymerization, freezing or plugging. When any of these conditions exist,
						consideration may be given to heating, use of devices employing special
						materials of construction, the use of liquid seals, or inserting.
1.
						  Amendment of subsections (f)-(g) and new NOTE filed 5-5-2014; operative
						  5-6-2014 pursuant to Government Code section
						  11343.4(b)(3)
						  (Register 2014, No. 19).
Note: Authority cited: Section
							 142.3, Labor
							 Code. Reference: Section
							 142.3, Labor
							 Code.