ISO 4512:2000

Overview

ISO 4512:2000 - Petroleum and liquid petroleum products: Equipment for measurement of liquid levels in storage tanks - Manual methods defines requirements for equipment used to measure, by manual methods, the liquid level or corresponding volume of petroleum and petroleum products in storage tanks and containers. The standard covers the instruments, markings and accuracy practices needed for reliable tank gauging, and complements other standards that address temperature and density measurement for quantity calculation.

Key topics and technical requirements

ISO 4512:2000 addresses the design, construction, graduation, marking and accuracy of manual gauging equipment. Major topics include:

• Dip-tapes: construction, material, coating, attachment, dimensions, graduation, zero datum and maximum permissible error.
• Dip-weights and winding frames: material, construction, mass and marking requirements to ensure reliable dipping.
• Dip-rods / Ullage-rods: rigid gauges for small tanks, including graduation and zero-datum marking.
• Ullage rules and water-finding rules: specifications for devices and scales used to measure ullage (air space) and detect free water layers.
• Interface-detecting pastes: guidance for pastes used to find oil/water interfaces.
• Portable electronic gauging devices (PEGDs): sensor probe and tape construction, safety, zero datum and accuracy of measurement for portable electronic instruments.
• Vapour-lock valves and gauging access points: equipment details for gauging under closed or restricted conditions.
• Terms and definitions: standardizes vocabulary (e.g., dip, gauging reference point, master dip-tape, free water).
• Traceability and calibration: use of master dip-tapes calibrated by accredited labs and traceable to national standards.

Applications and who uses it

ISO 4512:2000 is intended for practitioners involved in manual tank gauging and inventory control, including:

• Terminal and storage-facility operators
• Refineries and bulk fuel distributors
• Marine and shore-based bunker surveyors
• Inspection and calibration laboratories
• Procurement/specification teams selecting gauging equipment Using ISO 4512 helps ensure consistent, accurate manual level measurements for inventory reconciliation, custody transfer verification, leak detection, and routine inspections.

Related standards

• ISO 1998 (Petroleum industry - Terminology) - referenced for consistent terminology.
• IEC 60079-11 - for intrinsic safety requirements applicable to equipment used in explosive atmospheres.
• Other ISO standards cover temperature and density measurement needed to convert level to mass/volume.

ISO 4512:2000 is a practical, equipment-focused standard that supports reliable manual gauging of petroleum products in storage tanks and helps harmonize measuring practices across the petroleum industry.