Overview
EN ISO 13916:2025 - “Welding - Measurement of preheating temperature, interpass temperature and preheat maintenance temperature” (ISO 13916:2025) is a CEN-adopted international standard that defines how to measure and record temperatures critical to fusion welding. It applies primarily to fusion welding (and can be used for other welding processes as appropriate) and excludes post‑weld heat treatment temperature measurement. The document replaces the 2017 edition and provides practical rules for point of measurement, timing, equipment and recordkeeping to ensure repeatable, auditable temperature control during welding.
Key topics and requirements
- Point of measurement
- For weld thickness t ≤ 50 mm: measure on the surface facing the welder at a distance A = 4 × t (maximum 50 mm) from the groove edge.
- If heat source is outside the groove, measure on the weld metal or parent metal immediately adjacent to the weld preparation.
- For t > 50 mm: required temperature must exist at minimum 75 mm (or agreed distance) from the joint prep; measure on the opposite face where practicable or confirm after temperature equalization.
- Allow temperature equalization of about 2 minutes per 25 mm of parent metal thickness when confirming on the heated face.
- Time of measurement
- Interpass temperature: measure immediately prior to the next weld run.
- Preheat maintenance temperature: monitor during welding interruptions.
- Equipment
- Acceptable devices include temperature-sensitive materials (crayons/paints), contact thermometers (CT), thermocouples (TE), and contactless optical/electrical devices (TB).
- Calibration/validation guidance referenced to ISO 17662.
- Records and designation
- Measurement records should reference EN ISO 13916:2025 and include measured preheating, interpass and preheat maintenance temperatures (°C) and any deviations.
- Standardized designation examples are provided (e.g., "Temperature ISO 13916:2025 T 155 - CT").
Applications and users
- Who uses it:
- Welding engineers, welding procedure specification (WPS) authors, quality managers, inspectors, fabricators and contractors working in structural, pressure vessel, pipeline, offshore, and heavy fabrication industries.
- Practical uses:
- Defining and verifying preheat and interpass controls in WPS/PQR documentation.
- Supporting quality assurance, inspection, and regulatory compliance where controlled preheat is required to avoid cracking or metallurgical issues.
- Standardizing temperature measurement and records for audits and contractor handovers.
Related standards
- ISO 17662 - Calibration, verification and validation of equipment used for welding (referenced for equipment calibration).
- EN ISO 13916:2017 - previous edition superseded by EN ISO 13916:2025.
Keywords: EN ISO 13916:2025, preheating temperature, interpass temperature, preheat maintenance temperature, welding temperature measurement, welding procedure specification, thermocouple, contact thermometer, ISO 17662.