ASME GMGC gaskets and Kammprofile Gaskets

[DK44]

Are ASME GMGC gaskets and Kammprofile (KAM) gaskets are different.
I observed that ASME GMGC (understood to be Grooved metal Graphite covered) is listed in the code with m=4.25 and y=10100 psi (70 Mpa) where as Kammprofile gaskets are Low Stress(LS)gaskets as propagated by the suppliers with m=2 and y=17.2 Mpa. Accordingly the Seating load of ASME GMGC will be much higher(about 4 times?)than KAM. Hence KAM offers optimum Flange & Bolt design
1.What makes KAM Gaskets to offer low m&y
2.What are the construction differences between the two.
3.When designed with KAM gaskets with less bolting Torque, the supplied gaskets resembling KAM will act like GMGC demanding more Bolting Torque.
4. How to differentiate between the two.

 

[SnTMan]

DK44, in my experience, KAM (Kammprofile) and GMGC (Grooved Metal Graphite Covered) are identical except that Kammprofile is a tradename usually associated with the manufacturer Flexitallic. GMGC is a generic term normally associated with other manufacturers.

Both consist of a metal core with grooves on the faces running in the circumferential direction, each face covered with graphite based gasket material. The graphite facings provide sealing at a relatively low bolt load, the grooves prevent the facing from extruding from the joint.

This type of gasket is said to provide among the lowest leak rates available in ordinary gaskets and to afford good resilience to accomdate variations in seating forces during service.

The various manufacturers normally supply their own m & y values and may also recommend minimum applied gasket stress during seating and operation.

Couple of things to note, according to my Sec VIII, Div 1, 2017 Edition:
1) The Code m & y values you cite are for grooved metal gaskets, not including any non-metallic facings.
2) m & y values in Table 2-5.1 are not mandatory per the general note.

Regards,

Mike



The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[DK44]

Thank you SnTMan for your clarification.
1. Can we infer that for Grooved Metal gasket of ASME Listing with m=4.25 and y=70 Mpa, by providing 0.5 mm thick Graphite layers on both sides, there is a drastic change as m=2 and y=17.2 Mpa and it is qualified as a Low Stress Gasket.
2. Is there not a possibility of Graphite covering be dried / destroyed in service and then it behaving like ASME Grooved Metal Gasket demanding higher m and y per code. There will be troubles with Flange design / Bolting Torque / Joint Leakage in such instance.
3. Hope grooves configuration will be same for both types. Then only difference being Graphite covering.
4. What are the Temp / Pr/ Service limitations of KAM gaskets. Are these recommended by The KAM Gasket suppliers?

 

[SnTMan]

DK44, as best I can:

1) Your m & y for GMGC sound about right, but should be confirmed with supplier. I don't know what is intended by "qualified as Low Stress gasket".
2) Graphite is suitable for many, but not all, services. Often suppliers recommend sufficient bolting to maintain a certain applied gasket stress, for exasmple 12,000 or 15,000 psi - (83 - 103 Mpa). Consult with supplier.
3) Yes, as far as I know.
4) I'd say yes. Most gasket manufacturers have applications engineers on staff who are pleased to discuss such matters.

The problem with sloppy work is that the supply FAR EXCEEDS the demand