BSM Flat-Faced EPDM Union Seal

Stepped Flat-Faced Seal Geometry

Unlike toroidal O-rings used in recessed RJT or standard BSM groove unions, the BSM flat-faced EPDM seal has a stepped annular cross-section defined by outer diameter A, inner bore B, and intermediate step diameter C. It seats flush between a flat-faced BSM liner and male part to present a smooth bore transition.

EPDM Material and Temperature Rating

Molded from black EPDM elastomer, the seal is listed on the source datasheet with a maximum operating temperature rating of 120 °C. The source description also notes that the compound is formulated for food and beverage contact service.

Tabulated Dimensions Across 1" to 4"

The series specification covers six imperial and metric sizes: 1" / 25.4 mm (A = 39.7, B = 22.2, C = 26.9 mm), 1 1/2" / 38.1 mm (A = 52.4, B = 34.9, C = 39.6 mm), 2" / 50.8 mm (A = 65.1, B = 47.6, C = 52.3 mm), 2 1/2" / 63.5 mm (A = 77.8, B = 60.3, C = 65.0 mm), 3" / 76.2 mm (A = 90.5, B = 73.0, C = 77.7 mm), and 4" / 101.6 mm (A = 115.9, B = 98.4, C = 103.1 mm).

Mating Compatibility and Selection Notes

Verify whether your union assembly uses flat-faced BSM/CIP components or an O-ring groove before ordering, as flat-faced seals and O-rings are not interchangeable. Because axial thickness is not printed in the A/B/C table, confirm recess depth against the mating male end.