ASTM E595-07 Testing: Outgassing Evaluation of Materials for Total Mass Loss and Volatile Condensables
In high-vacuum and space environments, the outgassing behaviour of materials is not merely a performance concern — it is a mission-critical factor. Volatile compounds released by polymers, adhesives, coatings, and other organic materials can condense on sensitive optical sensors, solar cells, or precision instruments, causing irreversible degradation. ASTM E595-07 provides the standardised framework for quantifying these outgassing risks through precisely controlled vacuum-exposure testing.
What Is ASTM E595-07?
ASTM E595-07 is the standard test method for determining total mass loss (TML) and collected volatile condensable materials (CVCM) from outgassing in a vacuum environment. The test exposes a weighed material specimen to a high-vacuum environment at 125°C for 24 hours, then measures the mass lost from the specimen and the amount of volatile material that condenses on a cooled collector plate at 25°C.
This method applies to organic, polymeric, and inorganic materials — including epoxies, adhesives, coatings, elastomers, composite matrix resins, and thermal control materials — that are intended for use in spacecraft, satellites, or other high-vacuum environments where contamination must be rigorously controlled.
Primary Measured Properties
Total Mass Loss (TML): Quantifies the total amount of volatile substances (by mass percentage) emitted by the specimen during vacuum exposure at elevated temperature. NASA acceptance criteria typically set a maximum TML of 1.0%.
Collected Volatile Condensable Material (CVCM): The fraction of emitted volatile material that condenses on the collector plate at 25°C. CVCM indicates contamination potential for surrounding surfaces. NASA criteria typically set a maximum CVCM of 0.1%.
Water Vapour Regained (WVR): After vacuum exposure, the specimen is returned to ambient conditions and reweighed to determine how much moisture it reabsorbs, providing insight into its hygroscopic behaviour.
Test Procedure Overview
The test apparatus includes a heater bar assembly with twelve specimen chambers operating at 125°C and a collector plate maintained at 25°C. Specimens — typically 100 to 300 mg — are placed in the specimen compartment and weighed before and after testing. The vacuum system is evacuated to low-pressure conditions. After 24 hours, the heater bars are cooled, and specimens and collector plates are transferred to desiccators, allowed to equilibrate, and reweighed to determine mass changes.
Why Outgassing Testing Matters
Materials that pass visual inspection and standard mechanical qualification may still outgas volatile compounds under vacuum and heat. In space applications, contamination of optical sensors, solar panels, or reflective surfaces by even microscopic films of condensed volatiles can degrade spacecraft performance. In satellite assembly cleanrooms and high-vacuum electronics manufacturing, outgassing control directly protects the integrity of precision instruments.
Industry Applications
Aerospace and Space Systems: Qualification of polymers, adhesives, thermal control coatings, and composite materials for satellite and spacecraft use.
Defence Electronics: Evaluating materials used in vacuum or near-vacuum instruments, radar systems, and optical equipment.
Semiconductor Manufacturing: Assessing polymers and adhesives used in cleanroom environments or vacuum process chambers where contamination is a critical concern.
Research Instrumentation: Testing materials used in electron microscopes, particle accelerators, and other high-vacuum laboratory instruments.
Complementary Standards
ASTM E595 is often used alongside ASTM E1559 (dynamic outgassing rate measurement under vacuum), which provides time-resolved outgassing data rather than total mass loss over a fixed period.
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Infinita Lab is a leading provider of ASTM E595 and streamlined material testing services, addressing the critical challenges faced by emerging businesses and established enterprises. With access to a vast network of over 2,000+ accredited partner labs across the United States, Infinita Lab ensures rapid, accurate, and cost-effective testing solutions. The company’s unique value proposition includes comprehensive project management, confidentiality assurance, and seamless communication through a Single Point of Contact (SPOC) model. By eliminating inefficiencies in traditional material testing workflows, Infinita Lab accelerates research and development (R&D) processes.
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Frequently Asked Questions (FAQs)
What is ASTM E595-07 used for? ASTM E595-07 is used to evaluate materials for their outgassing characteristics in vacuum environments. It measures the Total Mass Loss (TML) and Collected Volatile Condensable Materials (CVCM) released when a material is exposed to elevated temperatures in a vacuum. This helps determine whether a material is suitable for use in sensitive applications, such as spacecraft, optics, or electronics, where outgassing could cause contamination.
Why is outgassing a concern in aerospace and vacuum applications? Outgassing can lead to the release of vapors that condense on nearby surfaces, forming unwanted residues. In spacecraft or satellite systems, this can degrade optical sensors, mirrors, and electronic components, impacting performance and reliability. Therefore, controlling outgassing is critical for mission success and material qualification.
What are acceptable outgassing limits? According to NASA and many aerospace standards: TML ≤ 1.00% CVCM ≤ 0.10% Materials meeting these thresholds are generally considered suitable for use in spacecraft.
Which materials are tested under ASTM E595-07? Typical materials include adhesives, coatings, polymers, elastomers, lubricants, tapes, composites, and insulation materials used in high-vacuum or cleanroom environments.
How is WVR (Water Vapor Regained) determined in ASTM E595-07? After the vacuum test, the specimen is returned to ambient conditions, allowed to equilibrate, and reweighed. The mass increase relative to the post-vacuum weight is the water vapor regained, reflecting the material's hygroscopic behaviour.
