ASTM F36: Standard Test Method for Compressibility and Recovery of Gasket Materials
This test method covers determination of the short-time compressibility and recovery at room temperature of sheet-gasket materials. It is not intended as a test for compressibility under prolonged stress application, generally referred to as "creep."
Source: ASTM International. Standard Test Method for Compressibility and Recovery of Gasket Materials - Designation: F36–99 (Reapproved 2009)
Thickness | Compressibility (average of 3 tests) |
Recovery (average of 3 tests) |
|
---|---|---|---|
ASTM F36 Procedure L
|
1.5 mm (1/16") |
56% | 8% |
ASTM F38: Standard Test Methods for Creep Relaxation of a Gasket Material
ASTM F38 provides a means of measuring the amount of creep relaxation of a gasket material at a predetermined time after a compressive stress has been applied. This test method is designed to compare related materials under controlled conditions and their ability to maintain a given compressive stress as a function of time.
Source: ASTM International. Standard Test Methods for Creep Relaxation of a Gasket Material - Designation: ASTM F38 - 00(2014)
Thickness | Relaxation (average of 3 tests) |
|
---|---|---|
ASTM F38-95 Method B
|
0.8 mm (0.030") | 23% |
ASTM F37: Standard Test Methods for Sealability of Gasket Materials
ASTM F37 provides a means of evaluating the sealing properties of sheet and solid form-in-place gasket materials at room temperature. This test method is designed to compare gasket materials under controlled conditions and to provide a precise measure of leakage rate.
Source: ASTM International. Standard Test Methods for Sealability of Gasket Materials - Designation: ASTM F37 - 06(2013)
Thickness | Leak rate | |
---|---|---|
ASTM F37-00 Method B
|
1.5 mm (1/16") | 0.3 ml/h |
This test method is currently being proposed as a new ASTM test method by the Committee F03 on Gaskets. ARLA determines the long term (aged) relaxation, leakage, weight loss and adhesion performance of gasket materials for pressurised bolted flanged connections. A mechanical integrity check of the material is also done. The method applies mainly to circular gasket products typically used in process or power plant pressure vessels and piping.
Source: ASTM International. New Test Method for AGED RELAXATION LEAKAGE ADHESION PERFORMANCE of Gaskets - Designation: ASTM WK26065
Gasket Thickness | % Relaxation (Average of 3 Tests) | Helium Leak Rate before aging (mg/s) | Helium Leak Rate after aging (mg/s) | |
---|---|---|---|---|
ARLA 5000 psi compressive stress
|
1/16" | 30.77 | 1.04E-04 | 1.42E-05 |
1/8" | 43.19 | 1.04E-03 | <1.0E-7 |
"The aim of the VDI guideline is to analyze and organize the applicable seal connection conditions based on the technical standard. Furthermore to complete the conditions, including latest research results, and advise the user in selection, interpretation, design, and assembling of flange joints in particular consideration of the gaskets."(1) "The here described blowout safety test of seals in sealing systems with even flanges corresponds with the current state of test engineering [...] a seal itself cannot accomplish blowout safety. It always depends on the entire system of the flange joint.
The blowout safety test is performed with nitrogen up to the 1.5-fold of the nominal pressure. Tests with higher pressures are allowed, if required. The internal pressure is to be increased stepwise, in steps of 5 bar to the above mentioned pressure. The holding period per pressure stage amounts to a minimum of 2 min.
As "blowout" is defined, if, within 5 s, a pressure decay of Δp ≥ 1 bar· (V0 = test room volume) is exceeded. The achieved internal pressure is to be indicated in the test record. If blowout did not occur until the maximum test pressure, the test is to be continued according to test step 2.
The internal pressure is discharged and the surface pressure is reduced to 5 N/mm2 with regard to lifting force caused by the internal pressure. Variations of the surface pressure are to be stated in the testing report."(2)
(1) Source: Verein Deutscher Ingenieure e. V.: VDI2200: Tight flange connections - Selection, calculation, design and assembly of bolted flange connections, June 2007, page 4
(2) Source: ibidem, page 64
Thickness | Exposure Temperature | Initial Gasket Stress | Test Step 1 | Test Step 2 | |
---|---|---|---|---|---|
VDI 2200 (06-2007) DN40 / PN40 Steel |
3.2 mm (1/8") |
230°C (446°F) |
30MPa (4351psi) |
Yes, 60 bar (870 psi) |
Yes, 60 bar (870 psi) |
This test method is currently being proposed as a new ASTM test method by the Committee F03 on Gaskets. This test method provides a means to determine realistic temperature limits for polytetrafluoroethylene (PTFE) based sheet or sheet-like gaskets to assist in avoiding catastrophic failure or blowout. This test method focuses on flanged joints common in the chemical process industry for moderate temperature ASME B16.5 Class 150 and Class 300 services.
Source: ASTM International. New Test Method for Hot Blowout and Thermal Cycling Performance for Polytetrafluoroethylene (PTFE) Sheet or Sheet-Like Gaskets - Designation: ASTM WK26064
Test 1: HOBT without thermal cycles.
Test 2: HOBT with 3 thermal cycles using temperature estimation from Test 1.
Test 3: HOBT with 3 thermal cycles using temperature estimation from Test 2.
Gasket Thickness | Blowout Temperature | Blowout Stress | Blowout Pressure | Trial Gasket Temperature Tgs | |
---|---|---|---|---|---|
HOBT with Cycling Draft 7
|
3.2mm (1/8") |
392.2°C (738°F) |
8.8MPa (1271 psi) |
30bar (435 psig) |
Actual: 339°C (635°F) Limited to: 315°C (600°F) |
This test method is currently being proposed as a new recommended practice for Gasket Constants for Bolted Joint Design by the Committee F03 on Gaskets. This practice determines room temperature gasket tightness design constants for pressurized bolted flanged connections such as those designed in accordance with The ASME Boiler & Pressure Vessel Code. It applies mainly to all types of circular gasket products and facings typically used in process or power plant pressure vessels, heat exchangers and piping including solid metal, jacketed, spiral wound and sheet type gaskets. As an option, the maximum assembly stress for those gaskets is also determined by this procedure.
Source: ASTM International. New Recommended Practice for GASKET CONSTANTS FOR BOLTED JOINT DESIGN - Designation: ASTM WK10193
Gb | The gasket stress at Tp = 1 when loading the gasket. It indicates the initial gasket stress required to seat the gasket with tightness. |
---|---|
"a" | The slope obtained by linear regression. It indicates the capacity of the gasket to ensure tightness. |
Gs | The gasket stress at Tp = 1 when unloading the gasket. It indicates the capacity of the gasket to maintain tightness when pressure is applied, as well as the gasket's sensitivity to unloading. |
Tp | The Tightness Parameter is dimensionless. A value of 1 corresponds to a Helium leak rate of 1 mg/s under atmospheric pressure for a gasket with an outside diameter of 150 mm. Note: the greater the Tp, the greater the gasket tightness. |
Tpmax | The maximum tightness obtained when loading the gasket. |
Tpmin | The minimum tightness obtained when unloading the gasket. |
ROTT Test Procedure for Soft Gaskets
ROTT Draft 9 SOFT Gasket Test Procedure
Gasket Thickness: 1/16" | Gasket Thickness: 1/8" | |
---|---|---|
Gb (psi) | 685 | 770 |
a | 0.271 | 0.274 |
Gs (psi) | 6.19E-02 | 9.38E-07 |
Tpmin | 1416 | 1962 |
Tpmax | 27706 | 16424 |
S100 (psi) | 2391 | 2716 |
S1000 (psi) | 4466 | 5099 |
S10000 (psi) | 8343 | 9573 |
Maximum Allowable Gasket Stress (psi) | Greater than 40031 (Equipment Max) | Greater than 40031 (Equipment Max) |