American Petroleum Institute

Manual of Petroleum Measurement Standards Chapter 19.3 - Evaporative Loss Measurement Part F - Evaporative Loss Factor for Storage Tanks Certification Program - First Edition
 N MPMS 19.3 PART F

Annotation

BACKGROUND

The purpose of this standard is to provide a mechanism for users of the API evaporative loss standards, and related documents, to verify the accuracy of device specific loss factors that they are requested to use. The certified loss factors developed under this standard denotes that an API certified facility certifies that the factors published for certain specific devices have been developed in a way that is consistent with that used for the generic or default factors published in the API standards. Use of the certified factors is believed to improve the accuracy of the calculated evaporative loss. The generic factors are not being withdrawn and are still published by API; this is an extension of the standards to incorporate new and more specific information.

API does not make any recommendation, conclusion, or warranty concerning a device having a certified loss factor. Likewise, the user should not draw any inference concerning the differences between devices that have certified factors and those that do not. Participation in the certified loss factor program is strictly voluntary.

API publishes certain standard methods for estimating the evaporative losses from storage tanks. These methods, namely MPMS 19.1 and 19.2, require inputs for various parameters that affect the quantity of material evaporated. Some of these inputs are loss factors that are specific to the type of equipment being considered. API has traditionally supplied default factors for these values that were developed from API's own testing programs. These factors are not meant to represent all equipment types or to specifically represent a particular device. They are referred to as generic loss factors. Specific devices may have loss factors that are different from those listed in 19.1 or 19.2. Users of the API calculation methods may have a need to reflect the capabilities of a specific device in their evaporative loss calculations.