A supplier sends a result headed “Pilling: Grade 4.” Before adding it to the approval sheet, ask what was tested, which method was used, whether the sample was washed first and when it was assessed. The number becomes useful when it stays with the material identity, test conditions and agreed requirement.
The review fields below are buying-team recommendations. They help connect evidence to a decision; they are not additional mandatory clauses of a test standard.
Start with the surface change you want to understand
Pills are small clusters of entangled fibres attached to a fabric surface. CottonWorks’ garment-durability guidance explains that fibre, yarn, construction, finishing and end use influence pilling. Other changes, including fuzzing or loss of surface cover, may accompany it.
A brushed cardigan and a smooth cotton crewneck begin with different appearances. Keep an untested reference and describe the change that concerns you. “Premium” or “fluffy” does not tell a laboratory what the buyer needs to assess.
The public summary of ASTM D4970/D4970M-22(2026) describes ratings from 5, for no pilling, to 1, for very severe pilling. Read a reported rating within its method and assessment conditions. It does not translate into a stated number of months of wear.
Identify the method before comparing grades
The ISO 12945-1:2020 abstract identifies a rotating pilling-box method. ISO 12945-2:2020 identifies the modified Martindale method. ASTM D4970 also uses a Martindale tester, but a shared apparatus name is not enough to establish equivalent test conditions.
Retain the complete method designation and edition. Ask the testing provider whether two reports provide a valid comparison before ranking their results.
Also check that the result is for the property you requested. ASTM D4966-22(2026) concerns abrasion resistance. An abrasion cycle count should not be substituted for a pilling assessment simply because both tests mention Martindale equipment.
Connect the result to the proposed garment
Record the style or sample reference, yarn and composition, colour or lot where known, knit structure, sampled area and finish version. Keep received and test dates, and ask about any reported deviations. These suggested fields help the team trace the evidence; check the actual reporting requirements with the laboratory.
An earlier plain-knit swatch does not automatically represent a newly brushed finish or a different sleeve structure. Show the proposed changes to the technical team or laboratory and ask which materials or garment areas require further evidence. Keep the answer with the sample approval record.
Keep preparation beside the result
ASTM D4970’s public summary allows testing in the received state, after laundering or dry cleaning, or in both states, as agreed between the parties. It also requires the tested state to be reported.
If a report says “after washing,” ask for the care procedure, number of treatments and drying conditions needed to interpret that description. Keep results from differently prepared samples separate. Combining them under one headline can hide the difference that matters to the order.
Read exposure and assessment together
Keep each reported exposure point with its result, using the time or cycles stated within that method. Do not convert one method’s exposure into another’s without a technical basis. If several points were assessed, retain each rather than selecting an unexplained favourable result.
ISO 12945-4:2020 addresses visual assessment of pilling, fuzzing and matting. Ask which assessment was made and whether it answers the buyer’s concern. A compressed phone photograph can help identify the specimen or show a concern; use the actual specimens and prescribed assessment conditions to resolve grading questions with the laboratory.
Separate the laboratory result from the release decision
ASTM D4970’s public guidance does not recommend the method for acceptance testing because interlaboratory data are unavailable; where it is used for acceptance, caution is advised. Discuss its suitability with the testing provider before treating a grade as a shipment rule.
Keep three items distinct in the order record: what the laboratory reported, what requirement the parties agreed, and who may approve production or shipment. Record the applicable specification, approval authority and how a disputed result will be reviewed. A report does not settle an acceptance requirement that was never agreed.
Example: two grade-4 reports that are not yet aligned
Illustrative comparison only: these are fictional reports, not Huayang measurements or customer results.
Report A gives grade 4 from a pilling-box test on material as received. Report B gives grade 4 from a modified Martindale test on a prewashed sample. The matching numbers do not establish equivalent performance.
Mark the comparison “not yet aligned.” Ask for the method editions, preparation, exposure points and assessment basis, then agree a comparable review with the testing provider. Check that the material represents the proposed bulk knit structure and finish. Until those questions are resolved, there is no supported basis for choosing a winner.
Use a controlled trial when changing the material
Woolmark’s wool-care guidance identifies fibre length, yarn twist, fabric cover and friction during wear as relevant factors. These offer questions for development, not a guaranteed recipe.
CottonWorks’ Textile Yarns booklet, dated January 2010, also explains that added twist affects stiffness, hand and torque. “More twist” is therefore not a complete buying specification.
For a proposed trial, record the variable changed, retain the original reference and compare both the intended appearance and the target performance. If several variables change together, note that limitation before attributing an improvement to one of them.
Keep a short report-review record
- Material
- Style, sample, yarn, colour or lot, knit area and finish version.
- Test
- Report ID, provider, method edition, preparation and reported exposure points.
- Assessment
- Grades and observations as reported, with supporting evidence references.
- Decision
- Agreed requirement, unresolved differences, responsible reviewer and next action.
Before approval, check five things: is the sample identified correctly; are method, preparation and exposure clear; does the assessment address the concern; is the acceptance basis recorded; and can the person releasing production see the limitations?
Use the test-planning page to discuss required evidence and the sample guide to keep approvals together. Neither a single report nor this checklist promises performance for every wearer or every production batch.
Sources and scope
Public material checked on 13 October 2026. Only the public summaries of the standards were reviewed; their full paid procedures were not obtained or reproduced. This guide supplies no universal passing grade or testing instructions and makes no claim that Huayang performs these methods. Sources provide technical context, not endorsement.
- CottonWorks — Garment Durability: surface changes and material influences.
- ASTM D4970/D4970M-22(2026) — public summary: Martindale pilling, preparation, grading and acceptance cautions.
- ISO 12945-1:2020 and ISO 12945-2:2020: public abstracts for pilling-box and modified Martindale methods.
- ASTM D4966-22(2026) — public summary: abrasion scope.
- ISO 12945-4:2020 — public abstract: visual assessment.
- Woolmark — Pilling: wool development and wear factors.
- CottonWorks — Textile Yarns (January 2010): twist trade-offs. The URL’s 2017 folder is not its publication date.