ASTM B117 – The Salt Spray Test
DECRA uses ASTM B117 salt spray testing to verify the corrosion resistance of the aluminum-zinc coated steel used in its stone-coated metal roofing panels, roofing accessories, and roofing fasteners.
Download the ASTM B117 – The Salt Spray Test document here.
ASTM B117-19, Standard Practice for Operating Salt Spray (Fog) Apparatus, is one of the roofing industry’s most widely recognized accelerated corrosion tests for evaluating the long-term performance of protective metal coatings.
Metal roofing systems are continuously exposed to rain, humidity, airborne contaminants, UV exposure, and changing temperatures. In coastal environments, salt-laden air can accelerate corrosion on roof panels, exposed fasteners, flashing, and roof penetrations.
Because of that, strong corrosion resistance is essential for maintaining the long-term durability, structural integrity, and appearance of a metal roof system.
What Does the ASTM B117 Salt Spray Test Evaluate?
The ASTM B117 salt spray test simulates harsh corrosive conditions by exposing metal roofing materials to a continuous salt fog environment inside a controlled chamber. The test is designed to evaluate how well protective metal coatings resist rust, coating breakdown, and corrosive undercutting over time.
For DECRA testing, roof panel specimens were intentionally scored to expose the base metal and test the effectiveness of the aluminum-zinc alloy protective coating under accelerated corrosion conditions.
DECRA roof panel specimens were subjected to 1,000 hours of salt spray exposure at chamber temperatures between 92°F and 97°F using a neutral 5% sodium chloride solution with a pH range between 6.5 and 7.2. After testing, the panels were cleaned, dried, and inspected for red rust formation, coating failure, and corrosive undercutting along the scored test areas.
ASTM B117 Salt Spray Test Results
DECRA roof panel specimens achieved the maximum ASTM B117 performance rating of 10, significantly exceeding the minimum passing requirement of 7. After 1,000 hours of salt spray exposure, the roof panels showed no destructive red rust corrosion. They maintained coating integrity throughout the testing process.
DECRA metal roofing fasteners are also subjected to ASTM B117 corrosion resistance testing. After 1,000 hours of salt-spray exposure, the fastener heads showed no signs of red rust.
Testing continued for an additional 500 hours, and the fasteners still showed no red rust after a total of 1,500 hours in the salt spray chamber.
Summary
DECRA Metal Roofs claim long life performance in all climate zones – verified by successful lab test procedures that support long life exterior exposure, backed by DECRA’s substantial warranty protection. DECRA delivers ‘peace-of-mind’ for all home and building owners who want to protect their investment with a long-life, attractive stone-coated metal roof system.
