Knit Fabric Sample Approval Checklist: Pass, Revise or Reject Before Bulk

Quick Answer: approve a knit fabric sample only after it passes four gates: it is the fabric you ordered (identity), it is free of visible defects, its physical and colour results meet written tolerances after the intended wash, and a garment prototype made from it performs as designed. Record every result in an approval record and keep a controlled reference sample. Anything that misses a tolerance is revised and resubmitted; anything with the wrong construction or a critical failure is rejected.

The Pass / Revise / Reject Workflow

1. Receive and log: give the sample an ID and record the mill reference, lot and submission round.
2. Check identity: construction, fibre content, colour and finish against your brief or spec sheet.
3. Inspect visually: look for holes, barré, snags, stains, slubs and shade variation across the width.
4. Measure as received: GSM, cuttable width, stretch and recovery.
5. Wash as the garment will be washed, then measure shrinkage, spirality, colour change and pilling.
6. Make and review a garment prototype.
7. Decide pass, revise or reject, record it, and seal the controlled reference sample.

Decision	When it applies	What happens next
Pass	Every agreed check meets its written tolerance and the prototype is accepted	Sign the approval record; cut and label the controlled reference sample; release to PP sample or bulk
Revise	Construction and fibre are correct, but one or more checks miss tolerance (for example GSM, shrinkage or shade)	Send the failed results to the mill; agree the correction; test the resubmitted sample against the same checklist
Reject	Wrong construction or fibre content, a critical defect, or a result the mill cannot correct on this fabric	Close the submission; restart development or move to an alternative construction

Knit Fabric Sample Approval Checklist

Use the reference methods your buyer and mill agree on. The methods below are published test standards; the pass limits are set per fabric and end use.

Check	What to confirm	Reference method
Sample identity	Construction, fibre content, colour, finish and mill reference match the brief or spec sheet	Written spec sheet and fibre content confirmation from the mill
Visual defects	Holes, barré, snags, stains, slubs, shade variation edge to centre	ASTM D5430 (4-point defect grading for rolls)
GSM	Mass per unit area against the target GSM and its tolerance	ASTM D3776
Width	Cuttable width against the marker or cut plan	Measured on the full sample width, selvedge excluded
Stretch and recovery	Elongation and recovery measured separately; growth after holding	ASTM D2594 (knitted fabrics with low power)
Shrinkage and spirality	Length and width change, and skew, after the intended wash	AATCC TM135, ISO 6330 washing procedures, AATCC TM179 skew
Colourfastness	Washing, rubbing, perspiration and light; colour difference to the approved standard	ISO 105 / AATCC methods from ISO/TC 38/SC 1 and AATCC; visual assessment per AATCC EP9
Pilling	Surface pilling after abrasion, before and after washing	ASTM D3512 (random tumble) or ASTM D4970 (Martindale)
End-use performance	Properties the garment depends on, such as opacity, hand feel, snag resistance or print behaviour	Agreed per product; see snagging and stability guides linked below

Test After the Intended Wash

A fabric that measures correctly off the roll can still fail once laundered. ISO 6330 sets domestic washing and drying procedures for textile testing and notes that washing parameters affect the results, so state the wash temperature, cycle and drying method on the approval record. If the garment will be enzyme-washed, mineral-washed or garment-dyed, test a sample that has been through that process rather than the fabric as delivered.

Measure before and after the wash on the same marked specimen, and report shrinkage, spirality and colour change as results with the method named. For method detail, see our fabric spirality and shrinkage test methods guide and the colour fastness test guide for knit fabric bulk approval.

Garment Prototype Review

Lab results do not show how a fabric behaves once cut and sewn. Make at least one prototype in the target size and check:

• Fit and drape against the design intent
• Side-seam twist after washing (a visible sign of spirality)
• Edge curl at hems and necklines
• Seam puckering and needle damage
• Opacity in light colours
• Neckband and cuff recovery after wear and washing
• Print or embroidery behaviour on the fabric surface

Approval Record Template

Keep one row per check. Each column below is what the record should contain.

Column	What to record
Sample ID	Your reference plus the mill's sample number and submission round
Check	The item from the checklist, for example GSM or shrinkage after washing
Test method	Standard and procedure used, including wash conditions where relevant
Result	The measured value or grade
Tolerance	The agreed limit for this fabric and end use
Decision	Pass, revise or reject for this check
Reviewer	Name and role of the person who assessed the result
Date	Date the result was reviewed
Controlled reference sample	ID and storage location of the sealed approved sample kept by buyer and mill

Which Criteria Are Agreed per Fabric and End Use

Test standards fix how to measure, not what counts as a pass. Agree these limits in writing for every fabric and product before sampling:

• GSM tolerance around the target weight
• Maximum shrinkage in length and width after the stated wash
• Maximum spirality or skew
• Minimum colourfastness grade for each test, and the colour difference allowed against the standard
• Minimum pilling grade
• Elongation and recovery values for stretch fabrics
• Defect points allowed per roll for bulk acceptance

A base-layer jersey, a stretch legging fabric and a brushed fleece will need different limits. Our guides on stretch fabric spandex ratio and recovery, knit fabric pilling and fibre QC, fabric snagging and dimensional stability tests and fabric stability in ponte, scuba and double knit explain how each property changes with construction.

Sample Approval With Runtang Tex

Runtang Tex develops knit fabrics from brief to approved sample for apparel brands across Europe, North America and Australia; see custom knit fabric development. Our fabric product pages list A4 size samples, a lab dip lead time of 3–7 days and a PP sample lead time of 15 days, for example on the jersey knit fabric page. Fabric inspection reports and lab test documentation are part of our standard pre-shipment procedure, and custom thresholds and colourfastness grades are confirmed at sampling, as described in our knit fabric quality control guide.

Send us your spec sheet with the target construction, GSM, colour standard and end use, and we will confirm which checks and records apply to your sample.

FAQ

What is the difference between pass, revise and reject in knit fabric sample approval?

Pass means every agreed check meets its written tolerance and the sample becomes the controlled reference for bulk. Revise means the fabric is close but one or more checks miss tolerance, so the mill adjusts and resubmits. Reject means the construction, fibre content or a critical result is wrong and the development has to restart or move to another fabric.

Should knit fabric samples be tested before or after washing?

Test after the wash the finished garment will receive. Shrinkage, spirality, colour change and pilling often only appear after laundering or garment washing, so measure the fabric as received and again after the intended wash procedure, for example a domestic laundering method such as AATCC TM135 or ISO 6330.

Who sets the tolerances for knit fabric sample approval?

The buyer and the mill agree them for each fabric and end use. Test standards define how to measure; they do not set one pass limit for every product. ASTM D5430, for example, notes that its defect grading supports acceptance of rolls and shipments when agreed by purchaser and seller.

What is a controlled reference sample?

It is a physical piece of the approved fabric, labelled with the sample ID, approval date and reviewer, and kept by both buyer and mill. Bulk shipments and reorders are compared against it, so it should be cut from the approved sample and stored away from light.