Types of Gaskets for Flanges

Types of Gaskets for Flanges

Table of Content

 

 

What is Flange Gasket?

What is Flange Gasket?

Pipe flange gaskets are sealing elements installed between mating faces of flange. ASME B16.20 gaskets in position between two pipe flanges. Industrial flange gasket are divide into 3 categories (1) Non-metallic (2) Metallic (3) Semi metallic. RTJ flange gasket are generally made from a rubber material or non asbestos sheet. Flange gasket used in anti vibration applications and liquids & gases. When selecting a raised face flange gasket, check this criteria such a fluid type, temperature of process, fugitive emissions legislation. Aaaaa are designed to process fluids or gases like a chemicals, oil, steam or water.

Three Main Categories of Steel Flange Gasket

Non Metallic Gasket Metallic Gasket Semi Metallic Gasket
PTFE Gasket Oval Ring Gasket Spiral Wound Gasket
Rubber Gasket Octagonal Ring Gasket Metal Jacketed Gasket
Ceramic Fibre Gasket – Camprofile Gasket

 

Top 10 Most Common Types of Gaskets for Flanges

Types Of Gaskets For Flanges Made From Gaskets Pictures
PTFE Gasket Made from Polytetrafluoroethylene PTFE Gasket
Graphite Gasket Graphite Foil or Sheet Graphite Gasket
Cork Gasket Compressed Cork Material Cork Gasket
Camprofile Gasket Non Metallic Sealing Material Camprofile Gasket
Elastomeric Gasket Rubber Layer and Metal Layer Elastomeric Gasket
Metal Gasket Stainless Steel, Copper, Aluminium Metal Gasket
Rubber Gasket Silicone, EPDM, Neoprene Rubber Gasket
Ring Joint Gasket Carbon steel, SORF Iron, SS 316, SS 304 Ring Joint Gasket
Spiral Wound Gasket Stainless steel, Flexible Graphite, PTFE Spiral Wound Gasket
Flat Gasket Flat Sheet Flat Gasket

 

Explained Temperature of Flange Gaskets for Oil and Gas Industry

ASME B16.20 Gasket Temperature Range

Types of Gaskets for Flanges PN Range Temperature Range Types Of Gaskets Materials
Metal Gasket PN2.5 to PN320 250°C to 550°C Stainless Steel
Graphite Gasket PN2.5 to PN320 200°C to 500°C Tanged
PTFE Gasket PN2.5 to PN320 200°C to +260°C Virgin
Non-Asbestos Gasket PN2.5 to PN320 100°C to 225°C Novus 30
Rubber Gasket PN2.5 to PN320 40°C to 120 °C EPDM

 

Why RTJ Flange Gasket Are Used?

Why RTJ Flange Gasket Are Used?

Types Of Gaskets Used in Oil And Gas Industry

Applications Recommended Gasket Conditions
Marine Metal jacketed gasket & NBR rubber gasket Saltwater
Power Generation Graphitegasket & serrated metal gasket >400°C
Food and Pharma PTFE gasket & silicone gasket Sterility requirements
Petrochemical Spiral wound gasket & RTJ gasket High Temperature

 

Choose the Right Flange Gasket Types : What You Should Know?

  • Fluid Type
  • Process Pressure and Temperature
  • The Flange Load
  • Flange Gasket Diameter
  • Fugitive Emissions Laws
  • Flange Gasket Thickness
  • Gasket Surface Finish
  • Stress Relaxation

Common Causes of Metal Flange Gasket Failure

Common Causes of Metal Flange Gasket Failure

Beginner’s Guide to Pipe Flange Gasket Standard and Compounds

Flange Gasket Standard

ASME B 16.20 Metallic Gasket
ASME B 16.21 Non Metallic Gasket
BS 3381 Spiral Wound Gaskets
DIN 11851 Clamp Gasket
ASME MSS SP-44, ASME B16.47, API 605
ISO 1127 Tri-Clamp Gasket
JSI 10k Spiral Wound Gasket
BS EN 12560-1:2001 Non metallic flat gaskets
BS EN 12560-2:2013 Spiral wound gaskets

 

Main Problems with PN16 Flange Gaskets

  • Wrong Material Selection
  • Flange Misalignment
  • Under Tightening
  • Over Tightening Bolts

Can A Flange Gasket Be Replaced With Gasket Tape?

Yes, low pressure cases, you can use spiral wound gaskets.

Properties and Compounds for Flange Gaskets

Name & Designation Chemical Resistance Composition Properties
Non-Asbestos Alkalis, oils, Mild acids Synthetic fibers bonded with NBR. Good service water and oil gasket
Teflon (TFE) Chemicals, Easily cleaned Polytetra flouroethylene Excellent solvent and chemical resistance
Red Rubber (SBR) Organic acids, alcohols Styrene butadiene Excellent abrasion resistance
Silicones (Q, Si) Moderate acids and ozone, oils Polysiloxane Good oil resistance
Red Rubber (SBR) Organic acids, alcohols Styrene butadiene Excellent abrasion resistance
Buna-N (NBR) Hydraulic chemicals and fluids Nitrile butadiene Excellent physical properties
EPDM (EPM) Heat, strong oxidizing chemicals Ethylene propylen diene molimers Chemical and aging resistance
Neoprene (CR) Moderate acids, oils, fats Chloroprene Good resistance to fluids petroleum

 

Select the Right RTJ Gasket Materials for Liquids and Gases

Common Gasket Materials

Non Metallic Gasket Metallic Gaskets
PTFE Soft iron
Non Asbestos Fiber Low Carbon Steel
Rubber 4-6% Chrome
Mica Stainless Steel (304, 316, 347, 410)
Ceramic Fiber Monel, Titanium, Duplex, Nickel Alloy

 

Comprehensive Guide to Full Face Gaskets Dimensions and Size Chart

FF Gasket Dimensions

NominalPipe Size Full Face Gasket Dimensions
Outer Diameter (Inch) Inner Diameter (Inch)
48 59 1/2 48
46 57 1/4 46
44 55 1/4 44
42 53 42
40 50 3/4 40
38 48 3/4 38
36 46 36
34 43 3/4 34
32 41 3/4 32
30 38 3/4 30
28 36 1/2 28
26 34 1/4 26
24 32 24
22 29 1/2 22
20 27 1/2 20
18 25 18
16 23 1/2 16
14 21 14
12 19 12 3/4
10 16 10 3/4
8 13 1/2 8 5/8
6 11 6 5/8
5 10 5 9/16
4 9 4 1/2
3 1/2 8 1/2 4
3 7 1/2 3 1/2
2 1/2 7 2 7/8
2 6 2 3/8
1 /2 5 1 7/8
1 1/4 4 5/8 1 5/8
1 4 1/4 1 5/16
3/4 3 7/8 1 1/16
1/2 3 1/2 13/16

 

What is The Best Flange Gasket For High Temperature?

Metallic gaskets and graphite gaskets is best pipe flange for high temperature applications.

How Is A RTJ Gasket Material Sheet Used?

RTJ gasket material sheet use to custom gaskets for unique flange types.

Raised Face Gasket Size Chart

Nominal Pipe Size Gasket Outer Diameter (Inch) Gasket of Inner Diameter (Inch)
24 28 1/4 24
22 26 22
20 23 7/8 20
18 21 5/8 18
16 20 1/4 16
15 19 15
14 17 3/4 14
12 16 1/8 12 3/4
10 13 3/8 10 3/4
8 11 8 5/8
6 8 3/4 6 5/8
4 6 7/8 4 1/2
3 5 3/8 3 1/2
2 4 1/8 2 3/8
1 1/2 3 3/8 1 29/32
1 2 5/8 1 5/16
3/4 2 1/4 1 1/16
1/2 1 7/8 27/32

 

Which Flange Gasket Type Is Most Common?

RTJ gasket and spiral wound gaskets are most common pipe flange gasket used in industrial piping systems.

Sealing Face Of Types of Gaskets for Flanges

Different Types of Flanges Applications Suitable Gasket
Tongue & Groove Flange High purity gas Metal serrated gaskets
RTJ Flange High pressure valves Ring gaskets
Raised Face Flange Oil pipelines Spiral wound gaskets
Flat Face Flange Low pressure water PTFE gaskets

 

Check Spiral Wound Gasket Color Codes and Torque Chart as per ASME B16.20

ASME Spiral Wound Gasket Color Code

Material Picture Max Temperature Color Coding
Nickel 200 Gasket Nickel 200 Gasket 600°C Red
Monel 400 Gasket Monel 400 Gasket 800°C Orange
Inconel 825 Gasket Inconel 825 Gasket 1000°C White
Inconel X-750 Gasket Inconel X-750 Gasket 1000°C Light Grey
Inconel 625 Gasket Inconel 625 Gasket 1000°C Gold
Inconel 600 Gasket Inconel 600 Gasket 1000°C Gold
Hastelloy C276 Gasket Hastelloy C276 Gasket 1000°C Beige
Hastelloy B2 Gasket Hastelloy B2 Gasket 1000°C Brown
Alloy 20 Gasket Alloy 20 Gasket 760°C Silver
Carbon Steel Gasket Carbon Steel Gasket 540°C Black
Stainless Steel 347 Gasket Stainless Steel 347 Gasket 870°C Blue
Stainless Steel 321 Gasket Stainless Steel 321 Gasket 870°C Turquoise
Stainless Steel 316L Gasket Stainless Steel 316L Gasket 800°C Green
Stainless Steel 304 Gasket Stainless Steel 304 Gasket 540°C Yellow

 

Maximum Hardness Values of RTJ Gasket

Material HRB Brinel
SS 410 RTJ Gasket 96 170
SS 347 RTJ Gasket 83 160
SS 316 Ring Type Joint Gasket 83 160
SS 304 Ring Type Gasket 83 160
4 – 6% Chrome RTJ Gasket 72 130
Low Carbon Steel RTJ Gasket 68 120

 

Gasket Thickness

Gasket Thickness Gasket Material
1/32 to 1/4 Viton
1/16 to 1/4 Vinyl
1/32 to 1/4 Silicone
1/32 to 1/4 SBR (Red Rubber)
1/32 to 2 Nitrile (NBR, Buna-N)
1/32 to 2 Neoprene
1/32 to 1 Natural (Pure Gum)
1/16 to 1/4 EPDM
1/16 to 1/4 Butyl

 

Spiral Wound Gasket Torque Chart

NPS Class 150 Flange Gasket Class 300 Flange Gasket
– Min – Max Torque Min – Max Torque
24 620 – 1000 800 – 1030
20 430 – 710 500 – 740
18 500 – 710 500 – 680
16 310 – 490 500 – 590
14 300 – 490 360 – 420
12 240 – 320 360 – 420
10 170 – 320 250 – 290
8 180 – 200 180 – 260
6 130 – 200 110 – 160
4 70 – 120 100 – 140
3.5 60 – 90 100 – 120
3 90 – 120 100 – 120
2.5 60 – 110 100 – 120
2 60 – 90 60 – 70
1.5 30 – 100 – 120
1.25 30 – 40 60 – 70
1 30 – 40 60 – 70
0.75 30 – 40 60 – 70
0.5 30 – 40 30 – 40

 

Flange Gasket Design

Types Of Shapes Shapes
Flange Gasket Flange Gasket
Rectangular with Circular Centre Rectangular with Circular Centre
Rectangular Gasket With Hole Rectangular Gasket With Holes
Rectangular Gasket Rectangular Gasket
Circular Gasket With Holes Circular Gasket With Holes
Circular Gasket Circular Gasket
Square Circular Centre With Holes Square Circular Centre With Holes
Square Centre With Holes Square Centre With Holes
Solid Square Solid Square
Flange Gasket with Holes Flange Gasket with Holes
Solid Disc Solid Disc

 

Spiral Wound Gasket Dimensions

Spiral Wound Gasket Dimensions

NPS (Inch) Outer Ring Sealing Element Inner Ring
Outside Diameter (d4) Outside Diameter (d3) Inner Diameter (d2) Inner Diameter (d1)
24 717.6 685.8 628.7 603.3
20 606.6 577.9 525.5 500.1
18 549.4 527.1 474.7 449.3
16 514.4 463.6 422.4 400.1
14 450.9 406.4 371.6 349.3
12 409.7 374.7 339.9 317.5
10 339.9 317.5 287.3 268.2
8 279.4 263.7 233.4 215.9
4 174.8 149.4 127 106.4
5 196.9 177.8 155.7 131.8
4 174.8 149.4 127 106.4
3 136.7 120.7 101.6 81
2½ 124 98.6 82.6 66.5
2 104.9 85.9 69.9 55.6
1½ 85.9 69.9 54.1 44.5
1¼ 76.2 60.5 47.8 38.1
1 66.8 47.8 31.8 26.9
3/4 57.2 39.6 25.4 20.6
1/2 47.8 31.8 19.1 14.2

 

RTJ Gasket Size Chart

Nominal Pipe Size ASME B16.5 ASME B16.47 Series A
– Pressure Class 150 Pressure Class 300#
26″ – R-93
24″ R-76 R-77
22″ – R-81
20″ R-72 R-73
18″ R-68 R-69
16″ R-64 R-65
14″ R-59 R-61
12″ R-56 R-57
10″ R-52 –
6″ R-43 –
5″ R-40 –
4″ R-36 –
3-1/2″ R-33 –
3″ R-29 –
2-1/2″ R-25 –
2″ R-22 –
1-1/2″ R-19 –
1-1/4″ R-17 –
1″ R-15 –

 

Raised Face Gasket Dimensions

Raised Face Gasket Dimensions

NPS Inside Diameter Outside Diameter (150)
DN600 610 718
DN500 508 606
DN400 406 514
DN300 324 410
DN200 219 279
DN100 114 175
DN80 89 137
DN65 73 124
DN40 48 86
DN20 27 57

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