Today, there are various gasket materials used where there was one. Flexible Graphite, filled PTFE and some of the Compressed Non-Asbestos sheets cannot take the stress loads that made CA work, without being damaged . In addition, each of these different materials require different stress loads to affect a seal. As a result, the proven installation practices that worked so well have been either altered or abandoned.
 

In hot or cold water and processing applications where the temperatures and pressures only require rubber gaskets, B7 Bolts are not necessary. In man processing plants there are applications for Grade 2, 5 and B7 Bolts. Remember, anything that can happen will happen. A Grade 2 Bolt in the wrong application can be easily over torqued. This bolt will stretch, lose its tensile strength and cause leaks.
 

Our extensive successful field experience has proven that standardizing on B7 bolts and this installation procedure provides long-life and leak free performance. You will get maximum performance from our gasket materials when you use our Gasket Installation Procedure.

2. Clean or replace your bolts with B7 bolts, nuts and washers. B7 bolts are highly recommended because they will pull straight or misaligned flanges tight enough together to properly compress the gaskets and effect a seal. Grade 2 bolts don't have the strength to withstand the torque required to achieve proper installation. A grade 2 head is bare and a B7 is black and has B7 on it as illustrated below.
 

3. Lubricate the B7 bolt's thread, nuts, washers and the underside of the head with Graphite based compound. This lubricant offers the best torque co-efficient and gasket stress distribution. This is based on Ecole Polytechnique of Montreal's test results. 
 

4. Flat washers are recommended to assure even distribution of the bolting force.
 

5. Use a torque wrench. The use of a torque wrench is highly recommended. This assures a longer life and leak free performance. Just as a good auto mechanic uses a torque wrench to install an automotive head gasket, a flange gasket should be torqued.

7. Torque the B7 bolts to the recommended value for your application. Make four even increment passes in a 12-6-3-9 o'clock pattern sequence as shown.

8. The appropriate stress on the gasket material you use is key to its success. The material used and the applications perimeters determines the required stress to seal any application. If you do not know how much torque should be applied to your bolts call us for the appropriate stress load for your application. Below you will find a torque guide specific to the Frenzelit gasket material listed. 

4" ring gasket for 150 lb. ANSI pipe flange with (8) 5/8" diameter bolts
Grade B7: National Course - Torque to 80% of yield = 198 ft./lb.
Grade 2: National Course - Torque to 80% of yield = 98 ft./lb.

Resulting Gasket Stress
Using Grade B7 bolts = 7170 stress
Using Grade 2 bolts = 3550 stress

Results: 100% higher gasket stress using grade B7 bolts

4" ring gasket for 150 lb. ANSI pipe flange
with (8) 5/8" diameter Grade B7 bolts lubricated with a graphite based compound.
One pass torquing: Bolting efficiency = 50%
Four pass torquing: Bolting efficiency = 75%

Resulting Gasket Stress
One pass = 4782 stress
Four pass = 7173 stress

Result: 50% higher gasket stress with four pass torquing

with a graphite based compound?

Grade B7: National Course - Torqued to 80% of yield
= 198 ft./lb.
4" ring gasket for 150 lb. ANSI pipe flange
with (8) 5/8" diameter Grade B7 bolts
Existing bolts, unlubricated
Friction factor = 0.25
New bolts lubricated
Friction factor = 0.15

Resulting Gasket Stress at 198 ft./lb.
Dry B7 bolts = 5738 stress
Lubricated B7 bolts = 9564 stress

Results: 67% higher gasket stress with lubricated bolts

Frenzelit NOVATEC 825F, 925F, Premium, novapress multi II and novapress multi EG

Compressed Non-Asbestos gasket sheets are specifically designed with a high performance anti-stick coating compound. No need to use a scrapper or hammer and chisel; your used gaskets will be hard and they will fall off the flange. Do not paint the gasket surface or the flange with a sealant, anti-stick or anything else; this will cause gaskets to leak. Install your gaskets dry! Used gaskets coming out broken or in pieces indicates an insufficient stress load on the gasket.
ANSI Standard Flanges with ASTM A-193 Grade B7 Bolts

Please call our technicians with your non-standard gasket application data to ensure there is sufficient gasket stress to affect a seal. Torque formulas are available if you choose to do the necessary calculations yourself.