API MPMS CH 7.1:2024 details the proper usage of different types of liquid-in-glass thermometers for the precise measurement of temperatures in hydrocarbon liquids. Alternative techniques, equipment, and procedures for temperature measurement are covered in the subsequent subsections of API MPMS Chapter 7.

The current chapter provides guidance on the manual procedures and tools for measuring the temperature of liquid petroleum and its products using liquid-in-glass thermometers. It addresses the general temperature measurement requirements for purposes such as custody transfer, inventory management, and marine measurements. The specific method and equipment chosen for temperature determination are subject to the agreement between the parties concerned.

The manual temperature measurement method encompasses:

Non-pressurized storage tanks and non-pressurized marine vessels;
Tanks and marine vessels lined with inert gas for blanketing.