FED. TEST METHOD STD. NO. 191A July 20, 1978 SUPERSEDING Fed
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Downloaded from http://www.everyspec.com FED. TEST METHOD STD. NO. 191A July 20, 1978 SUPERSEDING Fed. Test Method. No. 191 December 31, 1968 FEDERAL STANDARD FOR TEXTILE TEST METHODS This standard was approved by the Commissioner, Federal Supply Service, General Services Administration, for the use of all Federal agencies. U.S. GOVERNMENT PRINTING OFFICE : 1978 - 261-423/1108 Orders for this publication are to be placed with General Services Ministration, acting as an agent for the Superintendent of Documents. Single copies of this standard are available, without charge at the GSA Business Service Centers in Boston, New York, Philadelphia, Atlanta, Chicago, Kansas City, MO, Fort Worth, Houston, Denver, San Francisco, Los Angeles, and Seattle, WA. Additional copies may be purchased for 11.25 from the General Services Administration, Specifica- tions Activity, printed Materials Supply Division, Building 197, Naval Weapons Plant, Washington, DC 20407. FSC 83GP Downloaded from http://www.everyspec.com INFORMATION SHEET ON FEDERAL TEST METHOD STANDARDS This Federal Test Method Standard is issued in looseleaf form to permit the insertion or removal of new or revised sections and test methods. All users of Federal Test Method Standards should keep them up to date by inserting revised or new test methods as issued, and removing superseded and cancelled pages. New and revised material and cancellations will be issued under Change Notices which will be numbered consecutively and will bear the date of issuance. Change Notices should be retained and filed in front of the Alphabetical Index of the Standard until such time as they are superseded by a reissue of the entire Standard. Downloaded from http://www.everyspec.com FED. TEST METHOD STD. NO. 191A July 20, 1978 FEDERAL TEST METHOD STANDARD TEXTILE TEST METHODS AUTHORITY . This standard is issued pursuant to the Federal Property and Administrative Service Act of 1949, as ammended, and its application to the purchase of commodities referred to herein is mandatory on all Federal agencies. SECTION 1 - SCOPE AND CONTENTS 1.1 Scope. This standard describes the general physical, chemical and biological methods for testing textile fibers, yarn, thread, rope, other cordage, cloth and fabricated textile products for conformance with the require- ments of Federal and Military Specifications. It does not include certain methods which are described in the specifications for the materials to which they apply. This standard was prepared in order to eliminate unnecessary or undesirable variations in the general procedures. In the event that conflict should occur between the requirements of this standard and those contained in a specification or other type of procurement document on date of invitation for bid, the procurement document or specification shall govern. 1.2 Contents. The contents of this standard are as follows: Section 1. Scope and Contents Section 2. Definitions Section 3. Sampling and Number of Specimens Section 4. Atmospheric Conditions for Testing Section 5. General Notes Section 6. Numerical Index of Test Methods Section 7. Alphabetical Index of Test Methods Section 8. Conversion Equivalents Section 9. Test Methods Section 10. Supersession Data, Source Information, and Interested Agencies. Downloaded from http://www.everyspec.com FED. TEST METHOD STD. NO. 191A July 20, 1978 SECTION 2 - DEFINITIONS 2.1 Scope. For the purpose of this Standard and all procurement documents referring hereto, the following definitions shall apply: 2.2 General Definitions. 2.2.1 Acceptance of a lot. The approval of a lot conforming to contract or specification requirements. 2.2.2 Rejection of a lot. The disapproval of a lot as not conforming to the contract or specification requirements. 2.2.3 Standard sample. A standard sample is a sample of material selected or designated by the Government to meet material requirements and furnished by the Government for testing purposes. The standard sample is used in evaluating the quality of the test specimen for specific characteristics or properties by direct comparison of the test specimen and standard sample under identical conditions. Its purpose is to render a definite description of one or more properties being evaluated. 2.2.4 Test method. A test method is a detailed description of the required way for conducting a test; it is the act of evaluating or determining a required property or characteristic of a single sample unit by taking one or more measurement according to prescribed procedure. 2.2.5 Test result. A test result is the recorded measurement of a required property or characteristic for a single sample unit when such measurement is carried out in conformance with prescribed procedure. 2.3 Definitions applicable to sampling. 2.3.1 Random sampling. Random sampling is the procedure used to select items from the inspection lot so that each item in the lot has an equal chance of being included in the sample. There are many ways of drawing a random sample, perhaps the best one is the use of a table of random numbers. Such a table facilitates the selection of a valid random sample representative of the lot. 2.3.2 Sample. A sample consists of one or more units of a product drawn from a lot, the units being selected at random without regard for quality. 2.3.3 Sample size. The sample size is the number of units of a product in the sample selected for inspection. 2.3.4 Sample for test. A specified number of sample units (units of a product) taken from a lot for the purpose of testing for all physical and chemical properties for which requirements are specified. Downloaded from http://www.everyspec.com FED. TEST METHOD STD. NO. 191A 2.3.5 Sample unit (for test purposes). The sample unit is the total quantity of material necessary to obtain one test result for each of the properties and characteristics specified in the procurement document. In testing of small package units, the sample unit may be a package unit randomly selected from the material representing the lot. In testing commodities in which the units are individually too small to provide sufficient material for evaluating all the properties specified in the procurement document, the sample unit may be a sufficient number of units of the material, taken as an aggregate, to provide the quantity of material required. Downloaded from http://www.everyspec.com FED. TEST METHOD STD. NO. 191A July 20, 1978 SECTION 3 - SAMPLING AND NUMBER OF SPECIMENS 3.1 Sampling. The material to be tested shall be sampled as required in the applicable procurement document. 3.2 Number of specimens. The number of specimens to be tested for each property and each sample unit shall be as required by the test method unless specifically excepted in the procurement document. Downloaded from http://www.everyspec.com FED. TEST METHOD STD. NO. 191A July 20, 1978 SECTION 4 - ATMOSPHERIC CONDITIONS FOR TESTING 4.1 Humidity and temperature conditions for testing. Unless otherwise specified in the applicable test method or procurement document, physical tests of textiles and textile products shall be performed under standard atmospheric conditions and performed on specimens in moisture equilibrium under standard atmospheric conditions. 4.1.1 Standard atmospheric conditions. Standard atmospheric conditions for textiles and textile products testing are 65 percent ± 2 percent relative humidity at a temperature of 70°F ±2°F (21°C ± 1°C). 4.1.2 Moisture equilibrium. Moisture equilibrium is considered to have been reached when, after free exposure of the material to air in motion, controlled at standard atmospheric conditions as defined above, and change in weight in successive weighings made at intervals of one hour is no greater than 0.25 percent. 4.2 Preconditioning. In the event of dispute concerning the results of tests that may be affected by the moisture content, the material shall be preconditioned by being brought to moisture equilibrium with an atmosphere having a relative humidity of not over 10 percent and a temperature not over .25°F (52°C). The material shall then be brought to moisture equilibrium under standard atmospheric conditions as defined above and then tested. Downloaded from http://www.everyspec.com FED. TEST METHOD STD. NO. 191A July 20, 1978 SECTION 5 - GENERAL NOTES 5.1 Content of Methods. 5.1.1 Principal subdivisions. The methods are organized under the following headings: 1. Scope, 2. Test Specimen, 3. Number of Determinations, 4. Apparatus, Reagents and Method Cited, 5. Procedure, 6. Report and 7. Notes. 5.1.1.1 Scope. A statement of what the test method is intended to do, the property to be measured or evaluated, the material to which the method is applicable, and the limitations of the method. 5.1.1.2 Test specimen. This specifies that portion of a sample unit, its dimensions, and the way in which it is to be taken for a single measurement of a given property or characteristic, and any special preparation the specimen may require. 5.1.1.3 Number of determinations. A statement of the number of test specimens required from each sample unit to be tested. 5.1.1.4 Apparatus, reagents and method(s) cited. A description of the apparatus and reagents required to carry out the test and any other test method(s) forming an integral part of the overall procedure. 5.1.1.5 Procedure. Description of the step-by-step directions for carrying out the test. 5.1.1.5.1 Calculation of results. Description of the techniques required to insure that the required end result of the characteristic being tested is reached. 5.1.1.6 Report. Specific instructions for expressing the results to insure uniformity of expression and recording of the results. 5.1.1.7 Notes. Additional, but not mandatory information (eg.