Overview
CEN ISO/TR 17801:2017 (ISO/TR 17801:2014) is a technical report that provides a reference global solar spectral irradiance for a horizontal surface at sea level under relative air mass 1 (AM1) conditions. It was prepared to support the field of plastics weathering and degradation by giving a reproducible target spectrum to classify and evaluate solar simulators across the UV, visible and infrared wavelength ranges. The report reproduces ISO/TR 17801:2014 without modification and includes the tabulated reference spectrum recalculated using the SMARTS2 radiative transfer model.
Key topics and technical requirements
- Reference spectrum (Table 1): Tabulated spectral irradiance values (W·m‑2·nm‑1) beginning at 285 nm and continuing through the UV–visible–IR bands to define a global (direct + diffuse) solar spectrum for AM1.
- Modeling method: Data were generated with SMARTS2 (version 2.9.2) using inputs based on CIE No. 85 and an AM0 extraterrestrial spectrum (Gueymard).
- Defined atmospheric conditions used for the reference:
- United States Standard Atmosphere 1976 (USSA76) profile (with prescribed parameters)
- Total column water vapour: 1.42 cm
- Total column ozone: 0.34 cm
- Aerosol optical depth (500 nm): 0.1 (rural aerosol distribution per Shettle & Fenn)
- Ground (surface) reflectance: 0.2
- Carbon dioxide concentration assumed: 370 ppm
- Integrated irradiance target: 1 092 W·m‑2 incident on a sun-facing horizontal plane
- Direct beam includes a circumsolar component equivalent to a 5.6° field-of-view
- Definitions and terms: Clear definitions for global solar irradiance, spectral irradiance, and air mass are provided.
- Supporting material: Annex A supplies SMARTS2 input files to reproduce the reference spectrum.
Practical applications
- Classification and calibration of solar simulators used in accelerated weathering and photochemical ageing tests.
- Material ageing studies for plastics and polymeric materials where a standardized target solar spectrum is required.
- Laboratory test design for UV/visible/IR exposure and time-compression weathering protocols.
- Benchmarking and inter-laboratory comparisons where consistent spectral targets improve repeatability.
Who should use this standard
- Materials testing laboratories and R&D teams focused on polymer durability
- Manufacturers of solar simulators and test chambers
- Standards bodies and conformity assessment organizations working on weathering tests
- Photochemical and environmental testing engineers
Related standards
- Cited: CIE No. 85 (1989) - used as the original basis for global solar irradiance data and referenced throughout ISO/TR 17801.
Keywords: solar spectral irradiance, AM1, air mass 1, reference spectrum, solar simulator classification, plastics weathering, SMARTS2, CIE No.85, spectral irradiance at sea level.
