Q-Lab Leads Major Revision to ASTM G155, Standard Practice for Operating Xenon Arc Light Apparatus for Exposure of Materials, including Type I and Type II Daylight Optical Filters
ASTM G155 is ASTM’s Standard Practice for Operating Xenon Arc Light Apparatus for Exposure of Materials. This document is a performance-based standard that establishes principles and procedures for operating a xenon-arc accelerated laboratory weathering apparatus. It is widely-used and referenced, along with related test standards like ISO 4892-2 and SAE J2527.
However, ASTM G155 had not been updated since 2013, so ASTM‘s Weathering Committee G03 undertook a major revision, resulting in the recent publication of ASTM G155-21. Brad Reis, Q-Lab’s President and COO, served as project leader for this revision, which included contributions from other test instrument manufacturers as well as members of the scientific community.
The major change is the inclusion and clarification of so-called Type I and Type II Daylight optical filters. Modifying the spectrum of light generated by xenon arc lamps is critical for realistic materials testing. The “Daylight” classification has historically been intended to include filters that reproduce natural sunlight, for testing of materials exposed outdoors. However, the allowable spectral limits of the Daylight classification include filters that match historical borosilicate glass (like Daylight-B/B) as well as modern optical filters that match better the sun’s spectrum (Daylight-Q and Daylight-F). These filters differ in the shortwave ultraviolet (UV) light that they transmit, and thus can give different results for some products. The new revision of ASTM G155 continues to permit the use of both types, but explains clearly their differences so that users can understand them and make an informed choice. These same updates are being implemented in ISO’s committees for testing plastics and paints as well.
Other changes were also implemented in this revision of ASTM G155:
- Change in title and scope to reflect the intent of ASTM G155
- Inclusion of suggested chamber air temperature (CAT) values for each suggested test cycle
- Explanation that transitions between steps are not well controlled and may differ among test apparatuses
- Recommendation for specimen repositioning as a good laboratory practice
These revisions to ASTM G155 make this popular standard more accessible and understandable for experienced and novice users alike. For more information, check out Q–Lab’s recent free Webinar, ASTM G155 – What’s New and What You Need to Know.
