Overview
ISO 9022-7:2015 - Optics and photonics: Environmental test methods - Part 7: Resistance to drip or rain defines laboratory procedures for assessing how optical instruments and assemblies (including mechanical, chemical and electronic sub‑assemblies) withstand exposure to dripping water, steady rain and driving rain. The standard focuses on the effect of moisture on optical, climatic, mechanical, chemical and electrical performance; contamination of test water from airborne impurities is explicitly ignored.
Key topics and requirements
- Conditioning methods:
- Method 72 - Drip (dispenser plate, minimum 1 m distance from specimen).
- Method 73 - Steady rain (swivelling shower heads positioned ≥2 m above the specimen).
- Method 74 - Driving rain (steady rain with wind generator to simulate wind-driven precipitation).
- Measurements and instrumentation:
- Rain/drip rates measured with a Hellmann rain gauge (Prof. Hellmann type).
- Specimens mounted on a rotary table (1–2 r/min) to expose all upper surfaces evenly.
- Severity levels and parameters:
- Specimen temperature at start: 15 °C to 35 °C.
- Temperature difference (specimen vs water): 2 K to 20 K.
- Water level above dispenser plate examples: 10, 40, 75 mm.
- Example drip rates: 1.5 ± 0.5 mm/min, 3.5 ± 1 mm/min, 5.5 ± 1 mm/min.
- Exposure times and state of operation are defined by degree of severity.
- Procedure notes:
- Preconditioning: clean surfaces with neutral agents; restore service condition if required.
- Recovery: drying (no compressed air unless specified) and return to ambient temperature.
- Final inspection: visual or specified methods to detect internal moisture penetration.
- Identification: Environmental tests are coded per ISO 9022-1 (example: Environmental test ISO 9022-73-01-1 for steady rain, method 73, severity 01, state 1).
Applications and users
ISO 9022-7:2015 is used by:
- Optical and photonics manufacturers validating product resistance to rain/drip.
- Environmental test laboratories and quality assurance teams performing acceptance and qualification testing.
- Designers and reliability engineers of instruments with optical functions (e.g., imaging systems, sensors, inspection equipment) that may be exposed to wet environments.
- Regulatory and procurement specialists who specify environmental durability requirements.
Practical benefits include repeatable evaluation of water ingress risk, comparison between designs, and documented evidence of performance under simulated rain and drip conditions.
Related standards
- ISO 9022-1: Definitions and extent of testing (required reference).
- Other parts of ISO 9022 (e.g., Parts 2, 3, 6, 9) cover complementary environmental tests such as temperature, mechanical stress, dust and solar radiation - useful when combined environmental effects must be assessed.
Keywords: ISO 9022-7:2015, resistance to drip or rain, optics and photonics, environmental test methods, Hellmann rain gauge, steady rain, driving rain, drip test.