This chapter describes the methods@ equipment@ and procedures for manually determining the temperature of liquid petroleum and petroleum products by use of a portable electronic thermometer (PET). This chapter discusses temperature measurement requirements in general for custody transfer@ inventory control@ and marine measurements. The actual method and equipment selected for temperature determination are left to the agreement of the parties involved. The manual method covers: ?? nonpressurized tanks and nonpressurized marine vessel; ?? gas-blanketed tanks and gas-blanketed marine vessels. It does not cover hydrocarbons under pressures in excess of 21 kPa (3 psi gauge) or cryogenic temperature measurement@ unless the tank is equipped with a thermowell. The requirements of this chapter are based on practices for crude oils and petroleum products covered by API MPMS Ch. 11.1 (ASTM D1250). Requirements in this chapter may be used for other fluids and other applications. However@ other applications may require different performance and installation specifications.