ISO 12917-1:2017

Overview

ISO 12917-1:2017 - "Petroleum and liquid petroleum products - Calibration of horizontal cylindrical tanks - Part 1: Manual methods" specifies manual procedures for the calibration of nominally horizontal cylindrical tanks installed at fixed locations. The standard covers insulated and non‑insulated tanks, above‑ground or underground, pressurized tanks, and tanks with knuckle‑dish‑end, flat ends, elliptical or spherical heads. Tanks inclined from horizontal are covered provided a tilt correction is applied; practical application limits noted are about 4 m diameter and 10° tilt.

Key topics and requirements

• Scope and applicability: Manual calibration methods for horizontal cylindrical tanks used for petroleum and liquid petroleum products.
• Precautions: Safety and entry procedures follow the general rules in ISO 7507-1; safe‑entry certificates and disconnection/blanking of lines are required for internal work.
• Equipment requirements: Equipment must be traceable to a reference standard (per ISO 7507-1). Specific instruments discussed include:
  • Telescopic rod (readable to 1 mm; calibrated with uncertainty < 1 mm)
  • Laser distance meter (alternative to telescopic rod; also for tilt measurement; 1 mm resolution, calibrated < 1 mm)
  • Leveller (mechanical or optical/laser rotating instruments establishing a horizontal reference plane)
• Measurement procedures: Manual methods cover:
  • External and internal circumference measurements
  • Length measurements (total cylinder length, segment lengths, head lengths)
  • Gauge length and reference height determination
  • Tank tilt measurement and correction
  • Plate thickness, temperature, pressure, and deadwood assessment
• Computation and accuracy: Procedures for computing tank capacity tables, volume calculations, corrections for pressure and temperature, and guidance on calibration uncertainties (informative annex).

Practical applications and who uses it

ISO 12917-1:2017 is used to produce accurate calibration tables and capacity data needed for custody transfer, inventory control, regulatory compliance, and quality control. Typical users:

• Calibration laboratories and metrology services
• Refinery and terminal operations (fuel storage and distribution)
• Petroleum transport companies and tank farm operators
• Inspectors, surveyors and regulatory bodies involved in custody transfer of liquid fuels
• Service providers performing tank gauging and calibration

Related standards

• ISO 7507-1:2001 - referenced for strapping and measurement equipment requirements and general precautions.
• Other parts of the ISO 12917 series (listed on the ISO website) provide complementary methods and guidance.

Keywords: ISO 12917-1:2017, tank calibration, horizontal cylindrical tanks, manual methods, petroleum, calibration of tanks, tank capacity, tank tilt, telescopic rod, distance meter.