Last Man Standing: Bellofram® Silicones Only Manufacturer to Meet AA59588 CL3B GR30

April 16 2019

The most demanding measure of material tear and flex resistance

Silicone rubber is used in the manufacture of critical seals that can make or break product performance. Diverse industries rely on silicone to increase performance by regulating temperatures or creating a barrier to dust and contaminants, moisture, wind, and more. 

To easily determine the type of silicone product to specify for a given application, engineers rely on standards — a consistent set of product characteristics and manufacturing protocols that ensure uniformity, quality, and reliability. For product design engineers in military, aerospace, aeronautics, medical, and other critical markets, Bellofram® Silicones is now their single source for silicone rubber meeting the rigorous standard known as Commercial Item Description (CID) AA59588 CL3B GR30. 

CID AA59588 is a broad document updated in 2018 and covering six classes of silicone rubber, in various grades. The General Services Administration (GSA) has authorized its use by all federal agencies.
Within the broader AA59588 standard, the specific 3B class issues criteria for silicone rubber’s tear and flex resistance, setting performance metrics in various grades, including grades 30, 50, 60, 70, and 80. 

These grades measure performance over repeated use. Grade 30 is the rarest of all, ensuring performance at 500,000 cycles (for comparison, the next, Grade 50, indicates 140,000 cycles). It is here, AA59588 CL3B GR30, the absolute peak of expected performance over prolonged use, for which Bellofram Silicone has emerged as the only manufacturer whose product meets standard. 

“There are a number of standards to which manufacturers of silicone adhere — ASTM, BMS, ANSI, MIL. But for military, aerospace, and more, AA59588 is an essential compliance document,” said Matthew Wingertsahn, General Manager of Marsh Bellofram’s Elastomer Division. “Our proven performance up to and exceeding 500,000 cycles resets the bar for our design partners. When you consider how our silicone rubber seals influence safety, product quality, and the ability to deliver consistent results, we’re proud to be the only game in town.”

About The Marsh Bellofram Group of Companies
Headquartered in Newell, W. Va., USA, The Marsh Bellofram Group of Companies is an AS9100D and ISO9001:2015 certified global manufacturing collective. Its portfolio comprises high-performance OEM, industrial, and process control instrumentation, including timers and counters, digital controllers, RTDs and thermocouples, pressure instruments and gauges, FRLs, cylinders, natural gas and propane pressure regulators, valves, air pressure regulators and transducers, tank and liquid level measurement systems, pump and motor protection switches and alternating relays, as well as sensors, DC tachometers, encoders, industrial diaphragms, and specialty silicones. For more information, visit

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