GORE® Joint Sealant

Versatile and easy-to-install, this 100% ePTFE sealing cord is a cost-effective solution for large steel flanges in general-use applications.

Contact Us

United States

+1 800 654 4229


+61 2 9473 6800


+55 11 5502 7800


+8621 5172 8299


+33 1 56 95 65 65


+49 89 4612 2215

Hong Kong

+852 2622 9622


+91 22 67687000


+39 045 6 20 92 50


+81 3 6746 2600


+82 2 393 3411


+31 13 507 47 00


+48 22 6 45 15 37


+46 31 706 78 00


+65 6733 2882

South Africa

+27 71 467 7710


+34 93 4 80 69 00

United Arab Emirates

+971 2 5089444

United Kingdom

+44 1506 46 01 23

Resource Library

Gasket Product Selection Guide

Gaskets for Industrial Applications

Gasket Product Selection Guide

Product Selection Guides, 216.22 KB

Guide to verify that the application meets GORE® Gasketing qualifications, and to narrow the selection of products.

English (U.S.)


Joint Sealant, the first form-in-place gasket, was invented by Gore more than 40 years ago. It is a time-tested sealing solution for steel flanges with large diameters, rectangular or irregular shapes, and rough or pitted surfaces. When compressed, this soft, conformable cord forms a thin yet strong seal. It can also seal applications where available bolt loads are low.

Versatile GORE Joint Sealant is standard sealing material for many MRO (Maintenance, Repair and Operations) teams because it seals reliably – and because it’s easy and cost-effective to install. For most applications, just peel off the adhesive backing, apply to the surface, and overlap the ends. (For more complex applications, see our installation instructions.)

(1) Typically processes with limited thermal cycling, temperatures <150°C and pressures <10 bar.

What makes GORE Joint Sealant so versatile?

Gore expanded polytetrafluoroethylene technology

GORE Joint Sealant is made of 100% monoaxially expanded PTFE (ePTFE), using Gore’s expansion technology to create a high degree of fibrillation.

High fibrillation is what improves strength and seal performance, and creates the soft, conformable surface that readily fills minor flange irregularities.

GORE Joint Sealant is chemically-resistant to all media (pH 0-14) except molten/dissolved alkali metals and elemental fluorine, so it is versatile enough for use in strong alkali-, acid- and solvent-based chemical process systems.

GORE Joint Sealant - 100% monoaxially expanded PTFE

Simplicity and cost reductions

GORE Joint Sealant can instantly be formed in place to fit any shape, regardless of flange size or complexity. It adheres readily, and forms a gasket when the ends are overlapped – so even sealing vertical flanges is a one-person job.

With GORE Joint Sealant, creating custom large gaskets on the spot is swift and simple. No need to wait for one to be fabricated off-site. No need to receive pallets, or requisition trucks or crane-lifts. No special handling or maintenance required, either.

Gasket creation and gasket installation are faster and easier with GORE Joint Sealant. Its tight, durable seal means maintenance is minimal, too. With fewer interruptions and less downtime, productivity is higher all around – and so are the related cost savings.

Technical Specifications

Technical Information

Material 100% expanded PTFE (polytetrafluoroethylene), with monodirectional strength
This product is supplied with an adhesive backer only to aide in the product installation
Temperature Range -269°C to +315°C (-452°F to +600°F)
Chemical Resistance Chemical resistance to all media pH 0-14, except molten alkali metals and elemental fluorine.
Operating Range The maximum applicable pressure and temperature depend mainly on the equipment and installation.
  • Typical use: -60°C to 150°C (-76°F to 300°F); industrial full vacuum(1) to 10 bar (145 psi)
  • For higher pressures, please contact Gore.
Shelf Life ePTFE is not subject to aging and can be stored indefinitely. To ensure optimal adhesive function, we recommend use within two years of date of purchase when stored under normal(2) conditions.

(1) absolute pressure of 1 mmHg(Torr) = 133 Pa = 1.33 mbar = 0.019 psi
(2) 21°C (70°F) 50% Relative Humidity

Available Sizes

Width(3) 3 mm (1/8") 5 mm (3/16") 7 mm (1/4") 10 mm (3/8") 14 mm (1/2") 17 mm (5/8") 20 mm (3/4") 25 mm (1")

(3) GORE Joint Sealant is very conformable. Therefore prior to compression its dimensions are easily changed during storage and handling. Minor variation of dimensions in the uncompressed state have no influence on product performance.

Gasket Design Factors

EN 13555

EN 13555 provides the test method for generating the gasket parameters used in EN 1591-1 calculations. With the approval of EN 13555:2014, the informative Annex G now provides some guidance for generating gasket design parameters for form-in-place products. Test results per the 2014 revision will be available soon.

Due to the material properties of monoaxially expanded PTFE, the increase in the gasket width of GORE® Joint Sealant DF depends on the pressure exerted on it. For the configuration and calculation of flange connections it is therefore easier to use line forces instead of gasket stress. The line force, Q*, is the ratio of the force per unit length.

Gasket Constant Definitions

PQR A measure of creep relaxation at a predefined temperature. It is the ratio between the gasket stress after relaxation and the initial gasket stress. The ideal PQR value is 1. The closer the test value is to the ideal value, the lower the loss of gasket stress of the seal.
Q*min(L) The minimum required line force at ambient temperature for a certain leakage class L when the seal is first installed.
Q*Smin(L) The minimum required line force for a certain leakage class L in service.
Q*Smax The maximum line force that may be applied on the gasket, without damage or intrusion into the bore, at the indicated temperatures. It depends on the temperature and the seal thickness.
E*G This describes the recovery (elastic behavior) of a seal at load reduction. It is related to the modulus of elasticity. It depends on the applied line force, the seal thickness and the temperature.

General Test Method Description

PQR Creep Relaxation is measured at different temperatures, initial gasket stress, seal thickness values and flange stiffness values. The seal initially is exposed to the predefined gasket stress, then the temperature is increased and maintained for four hours. The residual gasket stress is then measured.
A load is applied to and removed from the seal in predefined increments, with the leakage being measured constantly. The internal pressure is usually 40 bar (test gas: helium).
The gasket stress is increased cyclically and then reduced to 1/3 of the previous gasket stress. The seal thickness is then measured. The test is repeated at various temperatures.

The E*G value is calculated from the load reductions and thickness changes. For Q*Smax, a sudden drop in seal thickness indicates failure. If a sudden drop occurs, the value of the loading step before failure is taken. In case no failure occurs, the maximum possible gasket stress of the test equipment is taken. The identified value is then used as the initial stress in a PQR test to verify the final Q*Smax under constant loading.

Test Results

EN 13555 specifies a test flange that is DN40/PN40 in size; therefore, GORE® Joint Sealant DF05 was tested using a stiffness of 500 kN/mm. Results for all other sizes were extrapolated from DF05 results using the following compression curve.

Compression Curves at Room Temperature


  Initial Line Force
5mm (3/16") 144(1) 2 20 0.73
144(1) 2 150 0.22

(1) corresponds to 30MPa initial surface pressure (initial width = 5mm)

Q*min (N/mm)

  L1.0 L0.1 L0.01 L0.001
3mm (1/8") 32 89 145 201
5mm (3/16") 50 141 228 317
7mm (1/4") 67 184 292 397
10mm (3/8") 95 258 408 556
14mm (1/2") 128 348 552 754
17mm (5/8") 160 446 721 1007
20mm (3/4") 165 460 747 1053

Q*Smin (N/mm)

  Q*A (N/mm) QA (MPa) L1.0 L0.1 L0.01 L0.001
3mm (1/8") 96 32 32 32 x x
192 64 32 32 x x
288 96 32 32 49 x
384 128 32 32 40 202
5mm (3/16") 96 20 48 48 x x
192 40 48 48 x x
288 60 48 48 73 x
384 80 48 48 61 110
7mm (1/4") 96 14 67 67 x x
192 27 67 67 x x
288 41 67 67 102 x
384 55 67 67 84 146
10mm (3/8") 96 10 95 95 x x
192 19 95 95 x x
288 29 95 95 144 x
384 38 95 95 119 207
14mm (1/2") 96 7 127 127 x x
192 14 127 127 x x
288 21 127 127 193 x
384 27 127 127 160 279
17mm (5/8") 96 6 160 160 x x
192 11 160 160 x x
288 17 160 160 245 x
384 23 160 160 202 354
20mm (3/4") 96 5 165 165 x x
192 10 165 165 x x
288 14 165 165 252 x
384 19 165 165 208 366

Q*smax (N/mm)

5mm (3/16") 2 20 2000 100
2 150 2000 100


  Thickness (mm) Temperature (°C) EG96N/mm (MPa) EG144N/mm (MPa) EG192N/mm (MPa) EG240N/mm (MPa) EG288N/mm (MPa)
5mm (3/16") 2 20 302 417 690 1059 880
2 150 254 543 554 989 872


m & y are gasket constants used for flange design as specified in the ASME Boiler and Pressure Vessel Research Code Division 1 Section VIII Appendix 2. Leak Rates versus Y stresses and m factor for Gaskets is currently being proposed as a new test method in the ASTM F03 Working Group.

Gasket Constant Definitions

m, maintenance factor, is a factor that describes the amount of additional preload required to maintain the compressive load on a gasket after internal pressure is applied to a joint.

y, seating stress, is the minimum compressive stress (psi) required to achieve an initial seal.

m 1.5
y 2500

AD 2000 B 7

There are no specific test standards for AD 2000 B 7 Gasket Parameters. However, an estimation is provided below. The 2015 edition of "AD 2000-Merkblatt B 7" refers to EN 13555 as a test standard(1) and uses table 9 from VDI 2200(2) for the conversion method. Please note that VDI 2200 states that such a conversion is invalid due to the different measurement methods. "Only the method according to DIN EN 1591-1 and AD 2000 in conjunction with DIN EN 1591-1 and FE analysis can be used for providing stability, leak tightness and TA Luft proof." (3)

Gore supports the use of the AD 2000-Merkblatt B 7 and provides the necessary gasket parameters below.

There are the following relations(1):
k0KD ≙ Qmin · bD
k1 ≙ (QSmin / p) · bD since m ≙ QSmin / p (4)
k0K ≙ Qsmax · bD


Qmin minimum required gasket stress at ambient temperature when the seal is first installed (based on EN13555)
QSmin minimum required gasket stress in service (based on EN13555)
QSmax maximum gasket stress that may be applied on the gasket at an indicated temperature ϑ (based on EN 13555)
bD width of the gasket
p internal pressure of the media
k1 AD 2000 B7 gasket parameter for service condition
k0KD AD 2000 B7 gasket parameter for gasket deformation
k0K AD 2000 B7 gasket parameter for gasket deformation in service at temperature ϑ

For GORE® Joint Sealant in 2 mm thickness and with an internal pressure of 10 bar (145 psi), this results in:

  • k1 = 10 • bD
  • k0KD = 18 MPa • bD
  • k0K= 200 MPa • bD temperature ϑ = 150°C (302°F)

If necessary for a specific application, Gore recommends to do individual conversions based on data from EN 13555.

The use of the general values given in table 1 of AD 2000-Merkblatt B 7(5) is not broadly recommended. However they may be applicable depending on the given situation.

Please also note that the quoted standards of DIN 2690 to DIN 2692 were superseded by EN 1514-1 in 1997.

(1) Arbeitsgemeinschaft Druckbehälter: AD 2000-Merkblatt B 7, Berechnung von Druckbehältern, Schrauben, Seite 4,, April 2015

(2) Verein Deutscher Ingenieure e. V.: VDI 2200, Tight flange connections - Selection, calculation, design and assembly of bolted flange connections, page 36, table 9, June 2007

(3) Verein Deutscher Ingenieure e. V.: VDI 2290, Emission Control - Sealing constants for flange connections, page 8, June 2012

(4) Please note that factor m = QSmin / p was defined by DIN V 2505 which was superseded by EN 1591-1 where m is no longer used

(5) Arbeitsgemeinschaft Druckbehälter: AD 2000-Merkblatt B 7, Berechnung von Druckbehältern, Schrauben, Seite 6, Tabelle 1, April 2015

Certificates & Applications

TA Luft test in accordance with VDI 2200

For the TA Luft1 test, the seal is installed in a DN40/PN40 steel flange, usually with a gasket stress of 30 MPa. The flange is then exposed to a defined temperature for minimum 48 hours. After cool down, leakage rate is measured over a period of at least 24 hours. The test pressure is 1 bar helium.

The ultimate final leakage rate after a test duration of 24 hours must remain below 10–4 mbar*l/(s*m) for the seal to qualify according to TA Luft.

1Federal Ministry of Germany for the Environment, Nature Conservation, Building and Nuclear Safety: First General Administrative Regulation Pertaining the Federal Emission Control Act (Technical Instructions on Air Quality Control - TA Luft), Joint Ministerial Gazette, July 30, 2012.

Oxygen Service

The Federal Institute for Materials Research and Testing (BAM) tests the sealing material compatibility for use in flanged connections with liquid and gaseous oxygen. Further information on the test procedure and the result can be found in the following test report. Please note that the test was conducted without adhesive backing.

Natural Gas Service (DVGW Type Examination)

The DVGW (Deutscher Verein des Gas- und Wasserfaches e.V.) is the German Technical and Scientific Association for Gas and Water. It tests sealing materials according to the DVGW VP 403 norm "Expanded polytetrafluoroethylene (PTFE) sealing profiles for flange connections in the gas supply industry." GORE® Joint Sealant (5mm (3/16") width) fulfills all requirements of this norm and is therefore suitable for natural gas applications.

Leachable Fluoride and Chloride

This test analyzes leachable water-soluble fluoride and chloride ions which can induce flange corrosion. The samples are leached for 24 hours at approximately 95°C in demineralized water. Contact Gore for further information if this testing is required for your application.

Safety Data Sheet (SDS)

GORE® Gasketing products meet the definition of an article; therefore, a Material Safety Data Sheet (MSDS) or Safety Data Sheet (SDS) is not required. However, for your convenience, a Product Safety Sheet (PSS), which details the intended use and proper handling of our articles, is provided.

Quality Management System

The Gore Sealant Technologies Quality Management System is certified in accordance with ISO 9001.



Not for use in food, drug, cosmetic or medical device manufacturing, processing, or packaging operations