Manual of Petroleum Measurement Standards, Chapter 7.1

Temperature Determination— Liquid-in-Glass Thermometers

SECOND EDITION, AUGUST 2017

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Contents

Page

1. Scope 1

2. Normative References 1

3. Terms and Definitions 2

4. General Precautions 3

   1. Safety 3

5. Units of Measure 3

6. Equipment and Design Requirements 4

   1. Liquid-in-Glass Thermometers 4

   2. Liquid-in-Glass Thermometer Assemblies 7

   3. Thermowells 8

7. Procedure for Temperature Determination 10

   1. Static Temperature Determination Using Liquid-in-Glass Thermometers 10

   2. Dynamic Temperature Determination Using Liquid-in-Glass Thermometers 18

8. Inspection, Verification, and Calibration Requirements 19

   1. Inspection 19

   2. Verification 19

   3. Calibration 21

Annex A (informative) Mercury-in-Glass Thermometer Alternative Testing Phase I—Tank Measurement . . 23 Annex B (normative) Emergent-stem Correction for Liquid-in-Glass Thermometers 25

Annex C (normative) Test Procedure for Determining Immersion Times of Liquid-in-Glass Tank Thermometers and Their Assemblies 34

Annex D (informative) Local Direct-reading Thermometers 36

Tables

1. Allowable Tolerances: Operating Thermometer vs Temperature Standard 6

2. Tank Thermometers 6

3. Dynamic Temperature Thermometers 7

4. Minimum Number of Temperature Measurements for Various Depths of Hydrocarbon Liquid

   in Storage, Lease, Ship and Barge Tanks 11

5. Comparison of Recommended Immersion Times for Woodback Cup-case Assemblies 13

6. Thermometer Assemblies and Temperature Levels for Tanks and Cargo Carriers 16

7. Temperature Measurements for Horizontal Cylindrical Tanks 17

1. Suggested Bath Temperatures 34

2. Time Intervals for Reading Thermometers 35

D.1 Tank Appurtenances for Temperature Measurement 36

Figures

1. Types of Glass Thermometers 5

2. Typical Cup-case Assembly 8

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   Contents

   Page

3. Typical Armored-cased Assembly 9

4. Typical Angle-stem Thermometer 9

1. Thermometers Immersed in Bath 26

2. Total-immersion Thermometer Partially Immersed in a Thermowell 27

3. Clip to Suspend Ambient Temperature Thermometer 28

4. Measuring Temperature of the Emergent Liquid Column 29

5. Measuring between Immersion Ring and Start of Temperature Scale (34 mm) 31

6. Determining How Many Degrees on the Thermometer 31

INTRODUCTION

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 Manual of Petroleum Measurement Standards (MPMS) Chapter 7.

vi

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 (All Sections)

  
  

• Chapter 3, Tank Gauging (All Sections)

  
  

• Chapter 8.1, Standard Practice for Manual Sampling of Petroleum and Petroleum Products

  
  

• Chapter 11.1, Physical Properties Data, Temperature and Pressure Volume Correction Factors for Generalized Crude Oils, Refined Products, and Lubricating Oils

  
  

• Chapter 12.1.1, Calculation of Static Petroleum Quantities—Upright Cylindrical Tanks and Marine Vessels

  
  

• Chapter 12.2, Calculation of Petroleum Quantities Using Dynamic Methods and Volumetric Correction Factors

  
  

• Chapter 15, Guidelines for Use of the International System of Units (SI) in the Petroleum and Allied Industries

  
  

• Chapter 18.1, Custody Transfer—Measurement Procedure for Crude Oil Gathered From Lease Tanks by Truck

RP 500, Recommended Practice for Classifications of Locations for Electrical Installations at Petroleum Facilities Classified as Class I, Division 1 and Division 2

RP 2003, Protection Against Ignitions Arising Out of Static, Lightning, and Stray Currents

1

2 API MANUAL OF PETROLEUM MEASUREMENT STANDARDS CHAPTER 7.1

RP 3000, Classifying and Loading of Crude Oil into Rail Tank Cars

ASTM 1

D1250, Standard Guide for Use of the Petroleum Measurement Tables

E1, Standard Specification for ASTM Liquid-in-Glass Thermometers

E77, Standard Test Method for Inspection and Verification of Thermometers

E344, Terminology Relating to Thermometry and Hydrometry

E2251, Standard Specification for Liquid-in-Glass ASTM Thermometers with Low-Hazard Precision Liquids

OCIMF 2

International Safety Guide for Oil Tankers and Terminals (ISGOTT)

NIST 3

NIST Special Publication 1088, Maintenance, Validation, and Recalibration of Liquid-in-Glass Thermometers

NFPA 4

NFPA 70, National Electrical Code

3 Terms and Definitions

For the purpose of this document, the following definitions apply. Refer to API Manual of Petroleum Measurement Standards (MPMS) Chapter 1 and ASTM E344 for the definition of additional terms used in this standard.

3.1

degree

3.1.1

degree Celsius (°C)

A derived unit of temperature in the International System of Units (SI).

3.1.2

degree Fahrenheit (°F)

A non-SI unit of temperature used in the U.S. Customary (USC) system of units. At any temperature, an interval of one degree Fahrenheit is the same as an interval of 5/9 degree Celsius.

°F = (°C * 9/5) + 32

3.2

temperature discrimination

The ability to sense and record the actual temperature of a liquid to the specified temperature increments.

1. American Society for Testing and Materials, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

2. Oil Companies International Marine Forum, 6th Floor, Portland House, Stag Place, London SW1E 5BH.

3. National Institute of Standards and Technology, 100 Bureau Drive, Stop 1070, Gaithersburg, MD 20899.

4. National Fire Prevention Association, 1 Batterymarch Park, Quincy, MA 02169.

TEMPERATURE DETERMINATION—LIQUID-IN-GLASS THERMOMETERS 3

3.3

thermometer

A device that measures temperature using any of a variety of different principles. A thermometer has two important components: a temperature sensor in which some physical change occurs that is dependent on temperature, and some means of indicating and/or transmitting this physical change as a value.

3.3.1

liquid-in-glass thermometer (LIGT)

A glass thermometer containing mercury or a low-hazard liquid that indicates the temperature being measured.

3.3.2

low-hazard liquid

A liquid that is biodegradable, non-hazardous and considered non-toxic in quantities specified for the thermometer specification.

3.3.3

mercury-in-glass thermometer (MIGT)

A glass thermometer containing mercury that indicates the temperature being measured.

3.3.4

partial-immersion thermometer

A liquid-in-glass thermometer designed to indicate temperatures correctly when the bulb and a specified part of the stem are exposed to the medium being measured.

3.3.5

total-immersion thermometer

A liquid-in-glass thermometer designed to indicate temperatures correctly when just that portion of the thermometer containing the liquid is exposed to the medium being measured.

1. General Precautions

   4.1 Safety

   
   

   Safety shall be considered for the specification, installation and operation of all equipment. Refer to API RP 500 and NFPA 70 for guidance. When loading liquids that can accumulate static charges, refer to the precautions described in the International Safety Guide for Oil Tankers and Terminals, Safety of Life at Sea, API MPMS Chapter 3, and API RP 2003. Care must be taken with all liquid-in-glass thermometers to prevent breakage, which will result in a safety hazard. If the liquid in the thermometer is mercury, additional care must be taken.

   
   

   4.1.1 Mercury Warning

   
   

   WARNING: Mercury has been designated by the Environmental Protection Agency (EPA) and many state agencies as a hazardous material that can cause central nervous system, kidney and liver damage. Mercury or its vapor, may be hazardous to health and corrosive to materials. Caution should be taken when handling mercury and mercury containing products. See the applicable product Safety Data Sheet (SDS) or Material Safety Data Sheet (MSDS) for details, and the EPA website https://www.epa.gov/mercury/faq.htm for additional information. Users should be aware that selling mercury or products containing mercury, or both, in your state may be prohibited by state law.

   
   

2. Units of Measure

For custody transfer, the means of temperature determination should be agreed to among the parties involved. Temperatures referenced in this document are those defined by the International Temperature scale of 1990 (ITS-90). Temperatures may be measured and expressed in degrees Celsius or in degrees Fahrenheit. This standard presents