ASTM F1276-23

Standard Test Method for Creep Relaxation of Laminated Composite Gasket Materials

SIGNIFICANCE AND USE
4.1 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. A portion of the torque loss on the bolted flange is a result of creep relaxation. Torque loss can also be caused by elongation of the bolts, distortion of the flanges, and vibration; therefore, the results obtained should be correlated with field results. This test method may be used as a routine test when agreed upon between the user and the producer.
SCOPE
1.1 This test method provides a means of measuring the amount of creep relaxation of a laminated composite gasket material at a predetermined time after a compressive stress has been applied.  
1.2 Creep relaxation is measured by means of a calibrated bolt with dial indicator.  
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Mar-2023
• ICS: 21.140 - Seals, glands
• Technical Committee: F03 - Gaskets
• Drafting Committee: F03.20 - Mechanical Test Methods

Relations

• Refers: ASTM A193/A193M-24 - Standard Specification for Alloy-Steel and Stainless Steel Bolting for High Temperature or High Pressure Service and Other Special Purpose Applications
• Effective Date: 01-Mar-2024
• Refers: ASTM B637-23 - Standard Specification for Precipitation-Hardening and Cold Worked Nickel Alloy Bars, Forgings, and Forging Stock for Moderate or High Temperature Service
• Effective Date: 01-Dec-2023
• Refers: ASTM F104-11(2020) - Standard Classification System for Nonmetallic Gasket Materials
• Effective Date: 01-Jan-2020
• Refers: ASTM F38-18 - Standard Test Methods for Creep Relaxation of a Gasket Material
• Effective Date: 01-Aug-2018
• Refers: ASTM F868-17 - Standard Classification for Laminated Composite Gasket Materials
• Effective Date: 01-May-2017
• Refers: ASTM B637-16 - Standard Specification for Precipitation-Hardening and Cold Worked Nickel Alloy Bars, Forgings, and Forging Stock for Moderate or High Temperature Service
• Effective Date: 01-Oct-2016
• Refers: ASTM A193/A193M-15a - Standard Specification for Alloy-Steel and Stainless Steel Bolting for High Temperature or High Pressure Service and Other Special Purpose Applications
• Effective Date: 01-Nov-2015
• Refers: ASTM A193/A193M-15 - Standard Specification for Alloy-Steel and Stainless Steel Bolting for High Temperature or High Pressure Service and Other Special Purpose Applications
• Effective Date: 01-Jun-2015
• Refers: ASTM A193/A193M-14a - Standard Specification for Alloy-Steel and Stainless Steel Bolting for High Temperature or High Pressure Service and Other Special Purpose Applications
• Effective Date: 15-Nov-2014
• Refers: ASTM A193/A193M-14 - Standard Specification for Alloy-Steel and Stainless Steel Bolting for High Temperature or High Pressure Service and Other Special Purpose Applications
• Effective Date: 01-Jun-2014
• Refers: ASTM F38-00(2014) - Standard Test Methods for Creep Relaxation of a Gasket Material
• Effective Date: 01-Mar-2014
• Refers: ASTM E691-13 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-May-2013
• Refers: ASTM A193/A193M-12b - Standard Specification for Alloy-Steel and Stainless Steel Bolting for High Temperature or High Pressure Service and Other Special Purpose Applications
• Effective Date: 08-Aug-2012
• Refers: ASTM B637-12e1 - Standard Specification for Precipitation-Hardening and Cold Worked Nickel Alloy Bars, Forgings, and Forging Stock for Moderate or High Temperature Service
• Effective Date: 01-May-2012
• Refers: ASTM B637-12 - Standard Specification for Precipitation-Hardening and Cold Worked Nickel Alloy Bars, Forgings, and Forging Stock for Moderate or High Temperature Service
• Effective Date: 01-May-2012

Overview

ASTM F1276-23: Standard Test Method for Creep Relaxation of Laminated Composite Gasket Materials establishes procedures for measuring the creep relaxation properties of laminated composite gasket materials under compressive stress. Creep relaxation refers to the gradual loss of compressive stress in gasket materials over time, which can significantly impact the effectiveness of bolted flange joints in various industrial applications. This standard provides a reliable test method to compare different composite gasket materials under controlled conditions, ensuring consistency and accuracy in material performance evaluation.

Key Topics

• Creep Relaxation Measurement: Evaluates how much compressive stress a laminated composite gasket material loses after a set period under load.
• Controlled Stress Testing: Utilizes a calibrated bolt and dial indicator assembly to measure changes in bolt length and, by extension, stress loss.
• Standardized Specimen Preparation: Specifies specimen size, thickness, and conditioning requirements for reproducible results across different laboratories.
• Test Conditions:
  • Tests may be conducted at room or elevated temperatures, such as 100°C (212°F), relevant to industry service conditions.
  • Procedures for cleaning, assembling, and lubricating the test apparatus are detailed for consistency.
• Precision and Reproducibility: Includes guidelines for repeatability and reproducibility, ensuring that results are reliable both within a single lab and across different testing environments.
• Data Reporting: Requires detailed documentation, including material designation, test temperature, duration, initial stress, specimen thickness, and percentage of stress relaxation.

Applications

• Material Selection for Gasket Manufacturing: Assists manufacturers and users in evaluating and comparing the long-term sealing performance of various laminated composite gasket materials.
• Quality Assurance and Specification Compliance: Used routinely between producers and users to confirm that materials conform to desired performance specifications regarding creep relaxation.
• Flange Connection Integrity in Industry: Supports industries such as oil and gas, chemical processing, and power generation, where bolted flange connections must maintain seal integrity under static or cyclic loading conditions.
• Correlation with Field Performance: Provides data that can be correlated with field experience to predict and mitigate torque loss due to creep relaxation in real-world installations.
• Research and Development: Supports R&D efforts focused on improving composite gasket material formulations for enhanced reliability and durability.

Related Standards

When using ASTM F1276-23, related ASTM standards may be relevant:

• ASTM F38 - Test Methods for Creep Relaxation of a Gasket Material
• ASTM F104 - Classification System for Nonmetallic Gasket Materials
• ASTM F868 - Classification for Laminated Composite Gasket Materials
• ASTM A193/A193M - Specification for Alloy-Steel and Stainless Steel Bolting
• ASTM B637 - Specification for Precipitation-Hardening Nickel Alloy Bars
• ASTM F436 - Specification for Hardened Steel Washers
• ASTM E691 - Practice for Interlaboratory Precision Studies

Practical Value

ASTM F1276-23 delivers a test protocol that helps users make informed decisions on gasket material selection based on standardized, repeatable creep relaxation data. Its application ensures reliable sealing performance, reduces maintenance due to flange leakage, and enhances operational safety in critical equipment. By adhering to this testing method, industries benefit from improved performance consistency, regulatory compliance, and minimized risk of joint failure due to material relaxation. This makes ASTM F1276-23 a vital resource for engineers, quality assurance professionals, and manufacturers in the gaskets and sealing materials sector.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: F1276 − 23
Standard Test Method for
Creep Relaxation of Laminated Composite Gasket Materials
This standard is issued under the fixed designation F1276; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope F104 Classification System for Nonmetallic Gasket Materi-
als
1.1 This test method provides a means of measuring the
F436 Specification for Hardened Steel Washers (Metric)
amount of creep relaxation of a laminated composite gasket
F0436_F0436M
material at a predetermined time after a compressive stress has
F868 Classification for Laminated Composite Gasket Mate-
been applied.
rials
1.2 Creep relaxation is measured by means of a calibrated
2.2 ASTM Adjuncts:
bolt with dial indicator. 3
Relaxometer, Method B (Adjunct to Test Method F38)
1.3 The values stated in SI units are to be regarded as the
3. Summary of Test Method
standard. The values given in parentheses are for information
only.
3.1 In this test method, the specimen is subjected to a
compressive stress between two platens, with the stress applied
1.4 This standard does not purport to address all of the
by a nut and bolt. Run at room or elevated temperatures, the
safety concerns, if any, associated with its use. It is the
stress is determined by measuring the change in length of the
responsibility of the user of this standard to establish appro-
calibrated bolt with a dial indicator. The bolt length is
priate safety, health, and environmental practices and deter-
measured at the beginning of the test and at the end of the test.
mine the applicability of regulatory limitations prior to use.
The percent relaxation is calculated from this.
1.5 This international standard was developed in accor-
dance with internationally recognized principles on standard-
4. Significance and Use
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom- 4.1 This test method is designed to compare related mate-
mendations issued by the World Trade Organization Technical rials under controlled conditions and their ability to maintain a
Barriers to Trade (TBT) Committee. given compressive stress as a function of time. A portion of the
torque loss on the bolted flange is a result of creep relaxation.
2. Referenced Documents
Torque loss can also be caused by elongation of the bolts,
distortion of the flanges, and vibration; therefore, the results
2.1 ASTM Standards:
obtained should be correlated with field results. This test
A193/A193M Specification for Alloy-Steel and Stainless
method may be used as a routine test when agreed upon
Steel Bolting for High Temperature or High Pressure
between the user and the producer.
Service and Other Special Purpose Applications
B637 Specification for Precipitation-Hardening and Cold
5. Apparatus
Worked Nickel Alloy Bars, Forgings, and Forging Stock
5.1 Relaxometer, composed of two platens, special drilled
for Moderate or High Temperature Service
E691 Practice for Conducting an Interlaboratory Study to and calibrated bolt, washer and nut composed of Specification
A193/A193M Grade B7 or Specification B637 Grade UNS
Determine the Precision of a Test Method
F38 Test Methods for Creep Relaxation of a Gasket Material N07718, or other alloys of construction that would satisfy the
calibration Procedure (see Annex) for the test temperature
specified and a dial indicator assembly as shown in Fig. 1.
This test method is under the jurisdiction of ASTM Committee F03 on Gaskets
5.2 Box End Wrench.
and is the direct responsibility of Subcommittee F03.20 on Mechanical Test
Methods.
Current edition approved April 1, 2023. Published May 2023. Originally
approved in 1990. Last previous edition approved in 2016 as F1276 – 99 (2016). Detailed working drawings of this apparatus are available from ASTM
DOI: 10.1520/F1276-23. Headquarters, 100 Barr Harbor Drive, West Conshohocken, PA 19428–2959 USA.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Order Adjunct No. 12-600-381-00.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Dario P. Bernasconi, 40 Farrington St., Stoughton, MA 02072, and Donald G.
Standards volume information, refer to the standard’s Document Summary page on Johnson, Metal Samples, P.O. Box 8, Munford, AL 36268, are suppliers of the
the ASTM website. relaxometer.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1276 − 23
TABLE 1 Test Method for Creep Relaxation of Laminated
Composite Materials Conditioning for Laminated Composite
Gasket Materials
Classification
F104
Type of Gasket Identification
Conditioning
Material in the First Two
Procedure
Nonmetallic Layers Numerals
of Six-Digit
Number
Compressed asbestos sheet; F11, F12, 1 h at 100 ± 2°C (212 ± 3.6°F)
asbestos beater sheet; F51, F52 Cool in desiccator over
flexible graphite anhydrous calcium chloride
21 to 30°C (70 to 85°F)
Asbestos paper and millboard F13 4 h at 100 ± 2°C (212 ± 3.6°F)
Cool as in Procedure A of
Classification F104
Cork composition F21, F23 At least 46 h at 21 to 30°C
Cork and cellular rubber (70 to 85°F) and 50 to 55 %
relative humidity
Cork and rubber F22 At least 46 h at 21 to 30°C
(70 to 85°F) and 50 to 55 %
relative humidity
Treated and untreated papers F31, F32, 4 h at 21 to 30°C (70 to 85°F)
from cellulose or other F33, F34 over anhydrous calcium
organic fibers chloride followed immediately
by at least 20 h at 21 to 30°C
(70 to 85°F) and 50 to 55 %
relative humidity
Compressed nonasbestos F71, F72 1 h at 100 ± 2°C (212 ± 3.6°F)
sheet; nonasbestos beater Cool in desiccator over
sheet anhydrous calcium chloride
21 to 30°C (70 to 85°F)
Nonasbestos paper and F73 4 h at 100 ± 2°C (212 ± 3.6°F)
millboard Cool as in Procedure A of
Classification F104
7.2 When the nonmetallic layers of the laminated composite
are of different types, the specimen shall be conditioned for 22
h in a controlled-humidity room or in a closed chamber of air
at 21 to 30°C (70 to 85°F) and 50 to 55 % relative humidity. In
all cases where testing is conducted outside the area of
specified humidity, specimens shall be removed from the
chamber one at a time as needed.
7.3 Other conditioning may be as agreed upon between the
producer and the user.
FIG. 1 Relaxometer and Dial Indicator Assembly
8. Procedure
8.1 Clean all surfaces and lightly lubricate the washer and
5.3 Steel Blanking Die. bolt threads; graphite and molybdenum disulfide have been
found to be acceptable lubricants.
6. Test Specimens
8.2 Place the specimens between the platens in accordance
6.1 Specimen size shall be 10.16 6 0.381 mm (0.400 6
with Fig. 1 making sure they are no closer than 2 mm (0.078
0.015 in.) wide by 31.75 6 0.381 mm (1.250 6 0.015 in.) long.
in) to the other pieces and the edge of the platens.
6.2 Four specimens are required per test.
8.3 Place the washer in position and screw on the nut, finger
tight.
6.3 A minimum of three tests shall be conducted.
8.4 Screw on the dial indicator assembly, finger tight, and
6.4 Nominal thickness of specimens shall be that of the
set the dial indicator at the zero reading.
laminated composite gasket.
8.5 Apply stress to the specimens by tightening the nut with
7. Conditioning
a wrench until the desired dial indicator reading is reached;
7.1 When all nonmetallic layers of the laminated composite record the reading (D ). Apply the stress in one continuous
o
are the same type, condition in accordance with that type as motion with a maximum loading time of 3 s. A bolt elongation
shown in Table 1. of 0.1222 to 0.1270 mm (0.00481 to 0.00500 in.) is typical for
F1276 − 23
TABLE 2 Precision and Bias Data
FORMAT A Precision of Creep Relaxation Test of Laminated Composite Gasket Materials Using Coefficient of Variation
Method of Presenting Results on a Percentage Basis
NOTE 1—S = standard deviation, CV = % coefficient of variation = (S × 100) ⁄(average), LSD = % least significant difference between two individual
test results, and based on a 95 % confidence level 52 2 CV .
s d
œ
Repeatability Reproducibility
Relaxation
(Within Laboratories) (Between Laboratories)
Material Values,
% Average
S CV, % LSD, % S CV, % LSD, %
A 25.4 2.01 7.92 22.4 2.49 12.6 35.6
B 8.05 0.90 11.2 31.6 1.70 23.9 67.6
C 23.9 1.85 7.73 21.9 1.08 8.95 25.3
D 20.5 1.11 5.44 15.4 1.15 7.84 22.2
E 30.5 1.52 4.98 14.1 2.93 10.8 30.6
F 29.0 0.87 3.01 8.5 1.32 5.46 15.4
FORMAT B Precision and Bias Table for Creep Relaxation of Laminated Composite Gasket Materials Based on Actual Units of Measure
Note—S = standard deviation, CV = coefficient of variation = (S)/(average), LSD = least significant difference between two individual test results, and based on a
95 % co
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: F1276 − 99 (Reapproved 2016) F1276 − 23
Standard Test Method for
Creep Relaxation of Laminated Composite Gasket Materials
This standard is issued under the fixed designation F1276; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method provides a means of measuring the amount of creep relaxation of a laminated composite gasket material at
a predetermined time after a compressive stress has been applied.
1.2 Creep relaxation is measured by means of a calibrated bolt with dial indicator.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and healthsafety, health, and environmental practices and determine
the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
A193/A193M Specification for Alloy-Steel and Stainless Steel Bolting for High Temperature or High Pressure Service and Other
Special Purpose Applications
B637 Specification for Precipitation-Hardening and Cold Worked Nickel Alloy Bars, Forgings, and Forging Stock for Moderate
or High Temperature Service
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
F38 Test Methods for Creep Relaxation of a Gasket Material
F104 Classification System for Nonmetallic Gasket Materials
F436 Specification for Hardened Steel Washers (Metric) F0436_F0436M
F868 Classification for Laminated Composite Gasket Materials
2.2 ASTM Adjuncts:
Relaxometer, Method B (Adjunct to Test Method F38)
3. Summary of Test Method
3.1 In this test method, the specimen is subjected to a compressive stress between two platens, with the stress applied by a nut
This test method is under the jurisdiction of ASTM Committee F03 on Gaskets and is the direct responsibility of Subcommittee F03.20 on Mechanical Test Methods.
Current edition approved Oct. 1, 2016April 1, 2023. Published October 2016May 2023. Originally approved in 1990. Last previous edition approved in 20092016 as
F1276 – 99 (2009).(2016). DOI: 10.1520/F1276-99R16.10.1520/F1276-23.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Detailed working drawings of this apparatus are available from ASTM Headquarters, 100 Barr Harbor Drive, West Conshohocken, PA 19428–2959 USA. Order Adjunct
No. 12-600-381-00.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1276 − 23
and bolt. Run at room or elevated temperatures, the stress is determined by measuring the change in length of the calibrated bolt
with a dial indicator. The bolt length is measured at the beginning of the test and at the end of the test. The percent relaxation is
calculated from this.
4. Significance and Use
4.1 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. A portion of the torque loss on the bolted flange is a result of creep relaxation. Torque
loss can also be caused by elongation of the bolts, distortion of the flanges, and vibration; therefore, the results obtained should
be correlated with field results. This test method may be used as a routine test when agreed upon between the user and the producer.
5. Apparatus
5.1 Relaxometer, composed of two platens, special drilled and calibrated bolt, washer and nut composed of Specification
A193/A193M Grade B7 or Specification B637 Grade UNS N07718, or other alloys of construction that would satisfy the
calibration Procedure (see Annex) for the test temperature specified and a dial indicator assembly as shown in Fig. 1.
5.2 Box End Wrench.
5.3 Steel Blanking Die.
6. Test Specimens
6.1 Specimen size shall be 10.16 6 0.381 mm (0.400 6 0.015 in.) wide by 31.75 6 0.381 mm (1.250 6 0.015 in.) long.
6.2 Four specimens are required per test.
6.3 A minimum of three tests shall be conducted.
6.4 Nominal thickness of specimens shall be that of the laminated composite gasket.
7. Conditioning
7.1 When all nonmetallic layers of the laminated composite are the same type, condition in accordance with that type as shown
in Table 1.
7.2 When the nonmetallic layers of the laminated composite are of different types, the specimen shall be conditioned for 22 h in
a controlled-humidity room or in a closed chamber of air at 21 to 30°C (70 to 85°F) and 50 to 55 % relative humidity. In all cases
where testing is conducted outside the area of specified humidity, specimens shall be removed from the chamber one at a time as
needed.
7.3 Other conditioning may be as agreed upon between the producer and the user.
8. Procedure
8.1 Clean all surfaces and lightly lubricate the washer and bolt threads; graphite and molybdenum disulfide have been found to
be acceptable lubricants.
8.2 Place the specimens between the platens in accordance with Fig. 1 making sure they are no closer than 2 mm (0.078 in) to
the other pieces and the edge of the platens.
8.3 Place the washer in position and screw on the nut, finger tight.
Dario P. Bernasconi, 40 Farrington St., Stoughton, MA 02072, and Donald G. Johnson, Metal Samples, P.O. Box 8, Munford, AL 36268, are suppliers of the relaxometer.
F1276 − 23
FIG. 1 Relaxometer and Dial Indicator Assembly
8.4 Screw on the dial indicator assembly, finger tight, and set the dial indicator at the zero reading.
8.5 Apply stress to the specimens by tightening the nut with a wrench until the desired dial indicator reading is reached; record
the reading (D ). Apply the stress in one continuous motion with a maximum loading time of 3 s. A bolt elongation of 0.1222 to
o
0.1270 mm (0.00481 to 0.00500 in.) is typical for a compressive force of 26.7 kN (6000 lbf). Remove the dial indicator assembly.
(The calibration procedure is outlined in Annex A1.)
NOTE 1—When testing materials thicker than 0.8 mm (0.03 in.), the time to tighten the nut may be extended to 5 s maximum to allow for the longer arc
required to apply the test load.
8.6 Place the specimen unit in a hot air-circulating oven for 22 h at 100 6 2°C (212 6 3.6°F), unless otherwise specified. The
maximum test temperature for Specification A193/A193M Grade B7 shall not exceed 204°C (400°F). The maximum test
temperature for Grade UNS N07718 shall not exceed 482°C (900°F).
F1276 − 23
TABLE 1 Test Method for Creep Relaxation of Laminated
Composite Materials Conditioning for Laminated Composite
Gasket Materials
Classification
F104
Type of Gasket Identification
Conditioning
Material in the First Two
Procedure
Nonmetallic Layers Numerals
of Six-Digit
Number
Compressed asbestos sheet; F11, F12, 1 h at 100 ± 2°C (212 ± 3.6°F)
asbestos beater sheet; F51, F52 Cool in desiccator over
flexible graphite anhydrous calcium chloride
21 to 30°C (70 to 85°F)
Asbestos paper and millboard F13 4 h at 100 ± 2°C (212 ± 3.6°F)
Cool as in Procedure A of
Classification F104
Cork composition F21, F23 At least 46 h at 21 to 30°C
Cork and cellular rubber (70 to 85°F) and 50 to 55 %
relative humidity
Cork and rubber F22 At least 46 h at 21 to 30°C
(70 to 85°F) and 50 to 55 %
relative humidity
Treated and untreated papers F31, F32, 4 h at 21 to 30°C (70 to 85°F)
from cellulose or other F33, F34 over anhydrous calcium
organic fibers chloride followed immediately
by at least 20 h at 21 to 30°C
(70 to 85°F) and 50 to 55 %
relative humidity
Compressed nonasbestos F71, F72 1 h at 100 ± 2°C (212 ± 3.6°F)
sheet; nonasbestos beater Cool in desiccator over
sheet anhydrous calcium chloride
21 to 30°C (70 to 85°F)
Nonasbestos paper and F73 4 h at 100 ± 2°C (212 ± 3.6°F)
millboard Cool as in Procedure A of
Classification F104
TABLE 2 Precision and Bias Data
FORMAT A Precision of Creep Relaxation Test of Laminated Composite Gasket Materials Using Coefficient of Variation
Method of Presenting Results on a Percentage Basis
NOTE 1—S = standard deviation, CV = % coefficient of variation = (S × 100) ⁄(average), LSD = % least significant difference between two individual
test results, and based on a 95 % confidence level 52 2 CV .
s d
œ
Repeatability Reproducibility
Relaxation
(Within Laboratories) (Between Laboratories)
Material Values,
% Average
S CV, % LSD, % S CV, % LSD, %
A 25.4 2.01 7.92 22.4 2.49 12.6 35.6
B 8.05 0.90 11.2 31.6 1.70 23.9 67.6
C 23.9 1.85 7.73 21.9 1.08 8.95 25.3
D 20.5 1.11 5.44 15.4 1.15 7.84 22.2
E 30.5 1.52 4.98 14.1 2.93 10.8 30.6
F 29.0 0.87 3.01 8.5 1.32 5.46 15.4
FORMAT B Precision and Bias Table for Creep Relaxation of Laminated Composite Gasket Materials Based on Actual Units of Measure
Note—S = standard deviation, CV = coefficient of variation = (S)/(average), LSD = least significant difference between two individual test results, and based on a
95 % confidence level = 2.8 (S).
Repeatability Reproducibility
Table Mat Range Average
S CV LSD S CV LSD
A 19.57–31.85 25.44 2.01 0.079 5.63 2.49 0.098 6.97
B 4.78–11.02 8.05 0.90 0.112 2.
...