The Raised Face is the most common type of Flange Facing used in the Chemical Plant Processing applications and is easily identifiable by the raised gasket seating area. The Raised Face portion runs from the bore of the Flange to the inside edge of the bolt circle. The purpose of the Raised Face design is to concentrate more pressure on a smaller gasket seating area to increase the pressure containing ability of the Flange joint. The Raised Face design allows for a combination of gasket types depending on the pressure and temperature ranges. A soft non asbestos material for standard service or the use of a combination of the soft non asbestos and a metal wound or Spiral wound type gasket for higher pressure/temperature service. The Standard Flange Facing for ASME B16.5 and ASME B16.47 is a 125-250 RMS Finish.
The Flat Faced Flange gasket surface covers the entire face of the Flange from the bore to the outer edge of the Flange, these Flanges utilize a Full Face gasket made of a soft non asbestos material. The finish for the ASME Flat Faced Flanges is the same as the Raised Face with a Finish of 125-250 RMS. The Standard Finish for the AWWA Flanges is 24 to 55 grooves per inch with the cutting tool having a .06” or larger radius which leaves a 250-500 RMS Finish. This will result in a rougher Finish which will give a better seal in Water Works applications. Contact Coastal Flange with any questions you may have or to receive a quote tailored to your requirements.