Separate the causes
The first value was taken straight after unpacking
Keep that value as a receiving observation, including date, packaging condition and known storage history. Ask the laboratory what conditioning and any preconditioning the agreed method requires. Do not prescribe a universal waiting time or use forced drying to make a result match the order.
The numbers use different areas or units
Obtain the specimen mass and area, cutter identification, balance/tare record and unit from both checks. GSM is grams per square metre; grams per linear metre additionally depends on usable width. A full-width result and a small specimen may also represent different sampling scopes.
The difference remains after a matched recheck
Retain individual results and a position map rather than reporting only an average. Check whether pieces came from the same roll, finish stage and width position. If the agreed, representative recheck still misses the contracted requirement, record the deviation and request a documented disposition; do not subtract a guessed moisture percentage.
Steps before deciding
- Identify article, colour, lot, roll, metres from the roll start, width position and face. Keep receiving and laboratory sample references linked.
- Record the agreed test method/version, conditioning route, reported temperature/humidity, start/end status and any deviation. The lab must confirm when its procedure is complete.
- Check verified specimen area, balance suitability, tare, units and whether selvedge is included. Preserve raw mass/area values, not just the calculated GSM.
- Use the agreed representative sampling plan and retain individual readings. Keep extra cloth for an independently agreed repeat; do not average unrelated lots together.
- Compare with the written finished-fabric specification and tolerance only after the bases match. Record release, further test or hold, with an owner and the missing evidence.
Worked example
Illustrative arithmetic, not test data: a verified 100 cm² specimen has an area of 0.01 m². Masses of 4.10 g and 4.00 g calculate to 410 and 400 g/m² respectively. The 10 g/m² difference is not itself a moisture correction or a pass/fail rule. Establish specimen identity, area and comparable testing conditions before interpreting it.
Buyer questions
Can I deduct a standard moisture percentage from the GSM?
Not as a shortcut to acceptance. A commercial moisture allowance, measured moisture content and a conditioned mass result are different bases. Use only the procedure and contractual basis agreed for this fabric.
Does a small swatch prove the whole roll's GSM?
It describes the sampled material under the reported method. Lot acceptance additionally needs an agreed representative sampling plan. A single cut from an unknown position cannot establish the whole shipment's uniformity.
Discuss the evidence with Fred Textile
Send Fred Textile the specification, both reports, raw mass/area calculations, sample and roll IDs, position map, conditioning details and affected quantity. Explain whether you need a repeat test, sampling clarification or a bulk-release decision. Email mrkcal@fredtextile.com; do not send a GSM number without its measurement basis.
Reference and limits
The ASTM link is the public catalogue for textile conditioning, not the complete licensed procedure. This recheck plan and arithmetic are editorial aids, not a Fred Textile test report, universal moisture correction or acceptance tolerance. Agree the applicable mass/area method with the laboratory.
ASTM D1776/D1776M: conditioning and testing textiles ↗