Suitable for use with flat face and raised face flanges and specified for high pressure/temperature service or where corrosive or toxic media are present. Note on use of inner rings: ASME B16.20 which covers spiral wound gaskets requires the use of solid metal inner rings in:

• Pressure Class 900, nominal pipe sizes 24” and larger
• Pressure Class 1500, nominal pipe sizes 12” and larger
• Pressure Class 2500, nominal pipe sizes 4” and larger
• All PTFE filled gaskets

ASME B16.20 recommends the use of inner rings if the user’s experience has shown inward buckling of the gasket. Flexitallic recommends the use of inner rings for the following applications:

• Vacuum service or suction side of rotary equipment such as pumps and compressors
• Aggressive media, high pressure or temperature
• Surface finishes smoother than 125 micro-inch
• If over compression of the gasket is a concern

It is customary to select inner ring material to be the same as the metal winding.