Simrit's E454 Compound Achieves NAS Specification

EPDM material certified for sealing all commercially available phosphate ester hydraulic fluids

PLYMOUTH, Mich. - Due to its continuous superior performance in real world applications, Simrit's E454 EPDM (ethylene-propylene rubber) compound was recently certified to NAS (National Aerospace Standard) 1613 Revision 5 Specification. The certification, which establishes the requirements for elastomer seal elements used in hydraulic systems using phosphate ester fluids, applies to all commercially available phosphate ester hydraulic fluids.

Simrit's E454 black compound is intended for NAS-1611-XXXA and NAS-1612-YYA (A-code) series O-rings. Developed by Simrit in 2005, the E454 compound is applicable for the following applications: commercial aircraft hydraulic flight control units (primary and secondary); power units and pumps; and aircraft braking systems.

Certification was achieved after a major manufacturer of flight control power units requested the material be tested to the NAS 1613 Specification. As a result, the material was tested on all type 5 fluids, making Simrit the only material supplier with this type of testing knowledge.

"Our latest certification highlights Simrit's dedication to developing and manufacturing sealing materials that meet our customers', as well as the aerospace industries', demanding needs," said Dr. Robert Keller, materials development manager, Simrit. "In the case of our E454 compound, the material's test results were one of the key reasons a leading aerospace manufacturer chose to work with us. This is just another example of how Simrit products consistently meet the needs of the evolving aerospace industry."

The NAS 1613 specification covers elastomeric seals used in phosphate ester hydraulic fluids, which are widely used in aircraft for hydraulically boosted primary and secondary flight controls and hydraulic brake systems. The seals involved are especially critical, since leakage of the phosphate ester hydraulic fluid is flight safety critical for hydraulic controls in all stages of the aircraft operation (taxi, take-off, climb, cruise, descent, landing and braking).

Because of the highly critical nature of these seals, the NAS-1613 specification is one of the most rigorous and extensive in the sealing industry. The specification was written to assure long-term seal performance through a wide temperature range from the frigid air of high altitude cruise flight to the extreme high temperature of anti-lock braking during landing. While there are many firms that manufacture O-rings, very few opt to participate in this specification because of the rigorous requirements for the material.

Simrit is part of the Freudenberg and NOK Group Companies, which have total annual sales of more than $7 billion. The global Freudenberg and NOK Group offers an extensive portfolio of precision-manufactured products for the aerospace, appliance, automotive, marine, medical, off-highway equipment, recreational vehicle and renewable energy markets. For more information, visit the Simrit website at

Adriana Ferrari / Jim Bianchi
Bianchi Public Relations
248-269-1122 /

Lisa Gentile

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