Hail Impact Testing for Solar Panels

As hail is a destructive natural force, hail impact testing is essential for solar panels to determine their mechanical strength against the impact of hailstones. High-velocity hail strike testing, as well as hail and stone hit testing, are services offered by Infinitalab.

Hail Impact Testing Methods for Solar Panels

Projectiles made of metal, stone, or transparent ice can be used in hail impact tests. To achieve high accuracy, laser-equipped systems are used that can provide repetitive impacts within a quarter inch of the desired target.

For QA and regulatory purposes, hail testing is a crucial component of an overall environmental testing program. The guidelines for hail impact testing for solar panels in specific are provided by the below ASTM standards:

1. ASTM E822 – Resistance of Solar Collector Covers to Hail by Impact with Propelled Ice Balls

ASTM E822 describes a method for assessing how well flat-plate solar collector cover plates can survive the impact forces of falling hail. To replicate hailstones, propelled ice balls are employed. Photovoltaic cells or arrays are not intended to be covered by this standard.

The ASTM E822 test method incorporates the following:

• Parameters that must be recorded and reported.
• Defines two types of test specimens.
• Discusses mounting techniques for specimens. 
• Details impact locations on each test specimen. 
• Offers an equation for calculating the velocity of ice balls of any size. 
• Demonstrates how to impact the test specimens with ice balls.

Pass or fail standards are not established by this procedure. It is outside the purview of this standard to determine what ice ball impact resistance levels are acceptable or undesirable. The ASTM E822 standard does not specify the size of the ice ball to be used in completing this test. 

The types of solar collector cover plate materials that can be affected by this approach include a wide variety of:

• Sheets that break easily, like glass.
• Plastic and other semi-rigid sheets.
• An elastic membrane, such as a plastic film.

2. ASTM E1038 – Resistance of Photovoltaic Modules to Hail by Impact with Propelled Ice Balls

The ASTM E1038 test standard determines if the photovoltaic modules can endure the impact forces of falling hail. To replicate hailstones, propelled ice balls are employed.

This ASTM E1038 test method includes the following: 

• An equation for calculating the velocity of ice balls of any size. 
• A method for impacting the test specimens with ice balls.
• A method for determining changes in electrical performance. 
• Specifications for parameters that should be recorded and reported.
• Defines test specimens and methods for mounting the specimens.
• Specifies impact locations on each test specimen.
• Both concentrator and non-concentrator modules can be tested.

There are no pass or fail levels in this test technique. The scope of this test procedure does not include determining what ice ball impact resistance levels are acceptable or unsatisfactory. There is no information regarding the size of the ice ball to be utilized in this test. Ice balls of different sizes can be utilized with this test procedure.

Video 01: Hail impact test on solar panels

Industrial Application of Hail Impact Test for Solar Panels

• Solar Energy
• Aerospace