TECHNICAL STANDARD
ASTM E337
Standard Test Method for Measuring Humidity with a Psychrometer (the Measurement of Wet- and Dry-Bulb Temperatures)
ASTM International
15(2023)
Current
WHAT DOES THIS STANDARD COVER?
Covers determination of atmospheric humidity using wet- and dry-bulb temperature measurements with a psychrometer.
WHY IS IT RELEVANT?
Relevant to environmental monitoring associated with coating application and surface preparation. Do not introduce a universal coating-application humidity, substrate-temperature or dew-point acceptance criterion. Project specifications and coating-manufacturer requirements govern acceptance.
KEY INSPECTION CONSIDERATIONS
The test method addresses measurement of humidity using wet- and dry-bulb temperatures with a psychrometer. Environmental assessment for coating work should consider relevant conditions together, including air temperature, surface temperature, relative humidity and dew point. Manufacturer and project application limits remain controlling.
WHAT THE STANDARD SHOULD NOT BE USED TO ASSUME
Relative humidity alone does not establish whether condensation will occur on a substrate. There is no single universal relative-humidity limit applicable to every coating product and application. Different products and specifications can establish different environmental restrictions.
PRACTICAL INSPECTION APPLICATION
Inspectors can take environmental measurements at representative locations and appropriate times during surface preparation and coating work. Results should be recorded and compared with the applicable product and project requirements. Changing environmental conditions may require additional monitoring.
RELATED TECHNICAL STANDARDS
RELATED TECHNICAL TOPICS
Environmental conditions; Relative humidity; Coating application
RELATED EXPERTISE
Coating Inspection; Technical Consultancy
ABOUT THIS TECHNICAL SUMMARY
Paint Inspection Ltd provides this information to help inspectors, engineers, asset owners and contractors understand the practical relevance of commonly referenced protective coatings standards. This page is PIL technical guidance and does not reproduce or replace the published standard. Users should refer to the current published standard, project specification, coating manufacturer requirements and other applicable contract documents when establishing project requirements or acceptance criteria.
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OFFICIAL STANDARD
PIL technical summaries are intended to explain the inspection relevance of industry standards and do not replace the published document.
STATUS AND SOURCE VERIFICATION
Official ASTM catalogue checked 2026-09-23. ASTM E337-15(2023) is listed by ASTM as Active. CMS designation, title and edition checked against the official ASTM catalogue record.