ASTM G197 is a reference standard that provides a table of solar spectral distributions for direct and diffuse radiation on 20° tilted and vertical surfaces. It is designed to help users work with consistent solar spectrum data when comparing performance, evaluating exposure conditions, or supporting engineering calculations. By defining a common reference for these surface orientations, it helps improve consistency in testing, analysis, and technical documentation tied to solar-related applications.

Purpose of ASTM G197

The purpose of ASTM G197 is to supply a standardized reference for solar spectral distributions under specific viewing and surface conditions. Its focus on direct and diffuse radiation for 20° tilted and vertical surfaces gives users a practical basis for comparing solar-related measurements or models. This can be useful when a project needs a consistent spectral input for analysis, specification work, or performance evaluation. As an ASTM standard, it supports clearer communication and more repeatable technical decisions.

Common use cases of ASTM G197

ASTM G197 is commonly used in solar energy and outdoor exposure work where reference spectral data may be needed for tilted or vertical surfaces. It can support studies involving photovoltaic systems, solar thermal components, coatings, glazing, and other materials affected by solar radiation. It is also useful in workflows that require a reliable spectral reference for testing, simulation, or product comparison. In practice, ASTM G197 helps align technical evaluations with a consistent solar radiation basis.

Why ASTM G197 matters

ASTM G197 matters because reference solar spectral data can affect how results are interpreted across testing and design activities. Using a recognized standard helps reduce ambiguity when comparing products, documenting assumptions, or validating models. It also supports procurement and compliance processes by giving teams a shared technical reference for solar exposure conditions. For organizations that depend on consistent performance evaluation, ASTM G197 can help improve repeatability and reduce risk in analysis.

• Reference solar spectral distributions
• Direct and diffuse radiation data
• 20° tilted and vertical surfaces
• Testing and modeling support
• Consistent technical reference