Overview
EN ISO 11699-2:2018 - Non‑destructive testing - Industrial radiographic films - Part 2 - specifies a user procedure for controlling radiographic film processing by means of pre‑exposed film strips and reference values. The standard defines roles for the film‑strip manufacturer (production, certification and storage of pre‑exposed strips) and for the user (processing strips, measuring optical densities and verifying compliance with a chosen film‑system classification).
Key topics and requirements
- Scope: Procedure for controlling film processing systems used in industrial radiography.
- Pre‑exposed film strips:
- Minimum exposed area 15 mm × 100 mm.
- Must contain at least ten optical density steps and a blank area for base + fog.
- Recommended to use film types representative of classified film systems (film system class C3 or C4 recommended).
- Manufacturer provides a certificate with reference values for each strip.
- Exposure and manufacture guidance:
- Example exposure arrangement uses a step wedge and precautions against scatter.
- Typical radiation source: constant‑potential X‑ray tube at approximately 150 kV with a 3 mm Cu pre‑filter; exposures chosen so one of the first six steps yields a net density ≈ 2 after processing.
- Density increments on steps are about 0.3 optical density.
- User responsibilities:
- Process the pre‑exposed strips in the facility’s processing system (automatic or manual) under normal operating conditions.
- Measure net optical densities using a calibrated densitometer.
- Evaluate processing parameters: limits for base density (D), speed index (Sx), contrast index (Cx), and checks for fixing and washing effectiveness.
- Record results, interpret against the manufacturer’s reference values and the film‑system classification.
- Additional elements:
- Guidance on mixed film systems (different film and chemistry manufacturers).
- Requirements for checking intervals and preparation of a test report to document compliance.
Practical applications and users
- Who uses it: NDT radiography technicians, QA/QC managers, film processing laboratories, radiographic film manufacturers, and inspection bodies.
- Why it’s useful:
- Ensures consistent film quality and reproducible radiographic image characteristics.
- Provides an auditable control method to verify processing chemistry, fixer/wash performance and processing equipment.
- Assists compliance with film‑system classification (ISO 11699‑1) and helps maintain traceable records for quality systems.
Related standards
- ISO 11699‑1 - Classification of film systems for industrial radiography (normative reference).
- ISO 18901 - Stability specifications for processed silver‑gelatin black‑and‑white films (normative reference).
Keywords: EN ISO 11699-2:2018, industrial radiographic films, film processing control, non‑destructive testing, pre‑exposed film strips, reference values, densitometer calibration, film system classification.
