API RP 2210:2000(R2015) pdf download.Flame Arresters for Vents of Tanks Storing Petroleum Products
1 Introduction
1.1 In addition to connections for liquid entry and with- drawal, every atmospheric Þxed-roof tank requires a vent that allows escape or entry of air and/or vapors to avoid develop- ment of pressure or vacuum conditions sufÞcient to damage the tank during liquid transfer or changes in ambient condi- tions. This publication discusses the beneÞts and detriments associated with the use of ßame arresters on these vents. 1.1.1 The provisions of this publication are intended for use when designing new facilities or when considering major expansions. It is not intended that the recommendations in this publication be applied retroactively to existing facilities. This publication also can be used as guidance when there is a need or desire to review existing facilities.
1.2 NFPA 30, Flammable and Combustible Liquids Code, lists requirements for tank vents in which ßammable and combustible liquids are stored. API Standard 2000, Venting Atmospheric and Low-Pressure Storage Tanks, and NFPA 30 cover the size and venting capacity to accommodate normal and emergency conditions of the tanks. Devices that are nor- mally closed, except when operating under pressure or vac- uum conditions, are often called pressure-vacuum valves. Such valves are normally required for ßammable liquids (see NFPA 30). Additional information on vents and pressure-vac- uum valves can be found in API Standard 620, Design and Construction of Large, Welded Low-Pressure Storage Tanks, and API Standard 650, Welded Steel Tanks for Oil Storage. Under certain circumstances, ßame arresters listed by the UnderwritersÕ Laboratories or approved by the Factory Mutual Engineering and Research Corporation are used in conjunction with, or in lieu of, a pressure-vacuum valve. The publications cited are considered standards for good practice, and may be incorporated in mandatory codes or ordinances in some jurisdictions.
4.2 Arresters have been made incorporating wire screens, small metal tubes, drilled holes, or passages between inter- leaved corrugated and ßat sheets of metal for use on tanks storing gasoline and similar ßammable liquids. Such devices have been tested and listed as acceptable by the Underwriters Laboratories or approved by the Factory Mutual Insurance Company. The listing is based on tests made with mixtures of hydrocarbon vapor and air of maximum explosiveness, with prescribed limitations on the manner of installation. For example, a pipe extension on the atmospheric side of the arrester that is longer than the extension used in the test inval- idates the listing (see UnderwritersÕ Laboratories Gas and Oil Equipment Directory and the Factory Mutual Approval Guide). For other vapors or gases and for installations that do not conform to the arrangement described in the listing, there is no assurance that the arrester will be effective.