Inner Ring On Spiral wound Gasket

[jafary64]

Hi my friends
we Have a Spiral wound Gasket Without inner ring then I want to know
1- is this material manufactured by standard and what is the standard
2- when can use this material according to standard
thanks a lot

 

[GBTorpenhow]

Is there an outer ring? Any markings?

 

[david339933]

ASME B16.20. You know you could find that in 5 seconds on google.