API 2551 : 1965

Scope
Outline of procedures
Tank-measuring equipment and its calibration
Measuring tapes
Accessory equipment
General practices
Part I. Measurement procedures
Conditions of measurements
Classification of tank services
Tolerance in measuring
Recalibration
Shell plate thickness
Horizontal tank measurement
Circumferential measurements
Expansion and contraction of steel shells due to liquid
pressure and/or working pressure
Expansion and contraction of steel shells due to
temperature changes
Head measurements
Expansion of heads due to liquid pressure or working
pressure
Effects of tank off-level
Deadwood
Interruption of measurements
Descriptive data
Part II. Tank capacity calculation procedure
General
  Engineering and mathematical principles
  Capacity units on gage tables
  Conversion of outside to inside circumference
  Significant figures
  Interpolations
  Extrapolations
  Weighted averages
  Tolerances
  Adjustments for variables
  Deadwood deductions
  Incremental height capacity basis
Deductions for circumference tape rises
  Deductions for projections
  Computed tape-rise deductions
Expansion and contraction of steel shells
  Expansion and contraction due to liquid pressure and/
  or working pressure
  Expansion of flat heads due to liquid pressure
  Effects of internal temperature on tank volume
Effects of tank off-level
  For operating control gage tables
  For critical measurements
Calculations
  Examples
  Distribution of elliptical heads
  Derivation of formula for volume of knuckle section
  Formula for volume of spherical segment
Appendix I - Areas of circular segments
Appendix II - Coefficients for partial volumes of
               spheres and hemispherical or semi-
               ellipsoidal heads
Appendix III - Volumes of bumped heads
Appendix IV - Procedure for computing the volume
               correction for thermal expansion or
               contraction of cylindrical horizontal
               tanks