API MPMS Chapter 17.11 / EI HM 52 PDF

API MPMS Chapter 17.11 / EI HM 52 PDF

This document provides guidance on the use, maintenance, and calibration of restricted and closed measurement and sampling equipment. It also provides guidance on preferred size and positioning for gauging and sampling fittings.

Measurement accuracy and representative sampling are essential to the sale, purchase, and handling of bulk liquids. Accurate measurements and representative sampling require the use of standardized equipment and procedures.

Government and regulatory agencies worldwide are imposing safety and environmental regulations that prohibit tank vessel operations from releasing hydrocarbons into the atmosphere. This has resulted in the restriction and, in some cases, the prohibition of traditional methods of obtaining cargo measurements and samples.

Consequently, methods and technologies are now available and used that allow cargo measurements and samples to be taken with no vapor release (closed) or with very limited vapor release (restricted).

There are a number of potential issues that can affect the reliability of samples obtained using restricted and closed sampling equipment, including equipment (both sampling devices and tank fittings) cleanliness and the requirement to transfer the sample into a secondary container. Furthermore, it should be noted that it may not be possible to obtain representative samples of nonhomogeneous cargoes due to the inherent nature of the cargo and the sampling restrictions.