API MPMS 7.1-2017 pdf download.Manual of Petroleum Measurement Standards , Chapter 7.1 Temperature Determination- Liquid-in-Glass Thermometers.
1 Scope This section describes how to correctly use various types of liquid-in-glass thermometers to accurately determine the temperatures of hydrocarbon liquids. Other methods, equipment, and procedures for temperature determination are described in the other sub-sections of API MPMS Chapter 7. This chapter describes the methods, equipment, and procedures for manually determining the temperature of liquid petroleum and petroleum products with liquid-in-glass thermometers. ” 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: -Non-pressurized tanks and non-pressurized marine vessels Gas-blanketed tanks and gas-blanketed marine vessels It does not cover hydrocarbons under pressures in excess of 21 kPa gauge (3 psi gauge) or cryogenic temperature measurement, unless equipped with a thermowell. The requirements of this chapter are based on practices for crude oils and petroleum products covered by API MPMS Chapter 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. 2 Normative References Manual of Petroleum Measurement Standards (MPMS) Chapter 1, Terms and Definitions -Chapter 2, Calibration of Upright Cylindrical Tanks (AII Sections) Chapter 3, Tank Gauging (AIl Sections) Chapter 8.1, Standard Practice for Manual Sampling of Petroleum and Petroleum Products
6 Equipment and Design Requirements 6.1 Liquid-in-Glass Thermometers 6.1.1 General Information Due to the identified hazards associated with mercury-in-glass thermometers (MIGTs), its use is being phased out. API, in collaboration with the U.S. Environmental Protection Agency, conducted a comparison study of MIGTs to other liquid-in-glass and digital thermometers in order to provide a comparison of the accuracies of each type of device. The testing indicated that alterative liquid-in-glass thermometers meeting the requirements in ASTM E2251 can be substituted for MIGTs. Annex A provides additional details of the testing that was conducted. 18.104.22.168 Thermometer Specifications Glass thermometers include total-immersion thermometers and partial-immersion thermometers (see Figure 1 and refer to ASTM E344). These thermometers should conform to the specifications in ASTM E1 or E2251 for thermometers, or to the National Institute of Standards and Technology (NIST) specifications. Calibration does not have to be done by a national metrology institute (NMI) (e.g. NIST in the United States), but the certifed instruments used for the calibration shall be traceable to a NMI. ASTM thermometers are designed to be either total immersion (thermometer immersed in the medium to be measured to the top of the thermometer liquid column) or partial immersion (thermometer in the medium to be measured to a specific depth marked on the thermometer). Tank thermometers used in conjunction with a cup-case assembly are total-immersion thermometers that are completely immersed into the tank but only a portion of the thermometer is immersed in the cup when read. Testing has shown that the accuracy of the reading is not affected when read quickly after being raised out of the tank. Operating thermometers that are used in static or dynamic measurement shall be compared on a regular basis (see Section 8) to a temperature standard.
22.214.171.124 Permanent Glass Thermometers Securely mount permanently installd glass thermometers in a thermowell and protect from breakage by the use of a housing. They shall have the same high resolution scale graduation interval and tolerance as glass test thermometers. These thermometers shall be calibrated and checked using test thermometers as described in Section 8. 126.96.36.199 Tank Thermometers Tank thermometers shall be of the total immersion type and shall be made in accordance with the specifications in ASTM E1 or E2251. Each thermometer shall be the liquid-in-glass type with nitrogen or another suitable inert gas flling the space above the liquid column, and with graduation marks permanently etched on its glass stem. Angle- stem thermometers may use a separate graduated scale, as discussed in 6.2.3. The thermometers listed in Table 2 shall be used.