ASTM D 461 : 1993

1.1 These test methods are applicable to all types of felt covered by Specification D2475 and as defined in Section 3 herein.

1.2 The procedures appear in the following sections:

Section Acid Content 27 Air Permeability 18 Referenced Documents 2 Ash 26 Bursting Strength 13 Conditioning 7 Terminology 3 Dimensional Changes (Relaxation Shrinkage) in Boiling Water-Length and Width 15 Fiber Identification 24 Flame Resistance 20 Length of Roll 8 Matter Extracted by 1,1,1-Trichloroethane 22 Matter Extracted by Water 23 Oil Retention 21 Oil Wicking 29 pH 28 Sampling Lots and Test Specimens 6 Splitting Resistance 14 Stiffness 19 Summary of Test Methods 4 Tensile Strength, "Breaking Load," and "Specific Strength" 12 Thickness of Conditioned Specimens 10 Thickness Change After Exposure to Boiling Water and Subsequent Drying 16 Significance and Use 5 Water Retained 17 Weight per Unit Area 11 Width of Roll or Sheet 9 Wool Content (Matter Soluble in a Solution of Sodium Hydroxide) 25

1.3 The values stated in SI units are to be regarded as the standard.

1.4 This standard should be used to measure and describe the properties of materials, products, or assemblies in response to heat and flame under controlled laboratory conditions and should not be used to describe or appraise the fire hazard or fire risk of materials, products, or assemblies under actual fire conditions. However, results of this test may be used as elements of a fire risk assessment which takes into account all of the factors which are pertinent to an assessment of the fire hazard of a particular end use.

1.5 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific warning statements are given in Note 9 and 25.4.

Note 1-The word "weight" is used in these test methods because of common trade practice, in place of the technically correct word "mass."