BS 2471:2005 pdf download.Textiles —— Woven fabrics—— Determination of massper unit length and mass per unit area.
4.2 Device to enable a specimen of full width to be cut at right angles to the selvedge.
4.3 Balance, capable of determining the mass of pieces or sample lengths (as relevant) to an accuracyof+0.2 % of the determined mass.
4.4 Table, having a smooth flat surface, a width greater than that of the woven fabric to be measured anda length of not less than 4 m.
5 Atmosphere for conditioning and testing
The atmosphere for conditioning and testing textiles shall be in accordance with BS EN ISO 139.
Pre-conditioning shall be carried out as described in BS EN ISO 139,unless it is known that the fabric, asreceived, can be conditioned from the"dry side”.
Equilibrium with the pre-conditioning or conditioning atmosphere shall be deemed to have been reachedwhen the difference between suecessive weighings, made at intervals of not less than 2 h, does not
exceed 0.5 % of the final mass of the fabric when conditioned in this atmosphere.
6 Procedure
6.1 Selvedges
If the mass per unit length (or area) of the selvedge differs appreciably from the mass per unit length (orarea) of the fabric, the mass per unit area shall be determined on a sample from which the selvedges havebeen removed along the outermost warp threads of the body, and calculation(s) shall be based on the massof the trimmed sample and its length and width.
6.2 Method 1: Measurement on short samples or cuttings that can be conditioned in thestandard atmosphere for testing
6.2.1 Ensure that the fabric is cut across the full width of the piece along parallel lines at right angles tothe selvedge and that the length of the sample is not less than 0.5 m and preferably 3 m to 4 m.
6.2.2 Condition the sample or cutting in accordance with Clause 5.
6.2.3 Determine the conditioned length of the sample in accordance with BS EN 1773.
6.2.4 If the mass per unit area is required, determine the conditioned width of the sample in accordancewith BS EN 1773.
6.2.5 Determine the conditioned mass of the sample.
6.2.6 Calculate the mass per unit length in accordance with 7.2, or mass per unit area in accordancewith 7.3,as required.
6.3 Method 2: Measurement on bulk pieces that can be conditioned in the standard atmospherefor testing
6.3.1 Condition the whole piece in accordance with Clause 5.
