API MPMS 19.3B:1997(R2012) pdf download.Manual of Petroleum Measurement Standards Chapter 19.3—Evaporative Loss Measurement
1 Scope
This test method may be used to establish evaporative rim- seal loss factors for rim seals used on external and internal ßoating-roof tanks. The test method involves passing a con- trolled ßow rate of air through a test chamber that contains a test liquid and a test rim seal, and measuring the concentra- tion of the test liquid vapor in the air streams entering and leaving the test chamber. This standard speciÞes the test apparatus, the instruments, the test procedure, and the calcu- lation procedures to be used. The variables that are to be measured are deÞned, and quality provisions are stipulated. The format for reporting the values of both the test results and their associated uncertainty are also speciÞed. This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems associated with its use. It is the respon- sibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
3 Terminology
3.1 DEFINITIONS
3.1.1 ACT facility: The entire facility used in the Air Con- centration Test (ACT) method. The ACT facility includes the test chamber, the sensors and data acquisition system, the air blower, the air inlet and outlet ducts, and the test liquid storage. 3.1.2 air concentration test method: The test method used to establish evaporative rim-seal loss factors for rim seals used on external, covered, and internal ßoating-roof tanks that involves passing a controlled ßow rate of air through a test chamber that contains a test liquid and a test rim seal, and measuring the concentration of the test liquid vapor in the air streams entering and leaving the test chamber. 3.1.3 covered floating roof: A ßoating roof that results from covering an external ßoating roof with a Þxed roof at the top of the tank shell. This effectively converts the external ßoating roof to an internal ßoating roof, while retain- ing the external-type of ßoating-roof design. These ßoating roofs are typically designed in accordance with Appendix C of the American Petroleum Institute Standard 650, Welded Steel Tanks for Oil Storage . 3.1.4 data acquisition: The process of receiving signals from the sensors, determining the values corresponding to the signals, and recording the results. 3.1.5 deck: That part of a ßoating roof that provides buoyancy and structure, and which covers the majority of the liquid surface in a bulk liquid storage tank. The deck has an annular space around its perimeter to allow it to rise and descend (as the tank is Þlled and emptied) without binding against the tank shell. This annular space is closed by a ßexi- ble device called a rim seal. The deck may also have penetra- tions, closed by deck Þttings, that accommodate some func- tional or operational feature of the tank. 3.1.6 deck fitting : The device that substantially closes a penetration in the deck of a ßoating roof in a bulk liquid storage tank. Such penetrations are typically for the purpose of accom- modating some functional or operational feature of the tank.