First identify the physical or mechanical property to be tested and its method. Then agree with the laboratory on specimen condition, whether preconditioning and conditioning are required, the conditioning atmosphere, the atmosphere during testing, the end condition, treatment of deviations and report contents. On receipt, check those conditions and sample identity before comparing results; keep missing information or unresolved deviations pending. Here conditioning means preparing specimens in a specified atmosphere under the applicable method. Ordinary flat resting indoors is not automatically laboratory conditioning.
This guide helps purchasing, product development and quality teams discuss physical and mechanical testing of knit yarn, fabric or garments with a laboratory. Individual test methods may require different preparation or environments. Do not automatically apply this guide's approach to chemical tests, care or other projects. A report saying “standard conditions” alone does not establish that order requirements were met, and one universal conditioning time should not be assigned to all materials.
Separate the test method from atmosphere requirements
The official ISO 139:2005 page describes a standard atmosphere for conditioning when determining physical and mechanical properties of textiles and an alternative standard atmosphere that parties may agree to use. The page lists a 2011 amendment and says the edition was reviewed and confirmed in 2025. Confirm with the laboratory the version, applicable amendment and particular test method required for the order. The name of an atmosphere does not prove that a sample has passed or that other tests have been conditioned.
For example, when discussing a physical result such as fabric strength or dimensions, first check whether and how the relevant method requires conditioning, then ask the laboratory to describe specimen preparation and test conditions. Different methods or customer specifications may have different requirements. If they conflict, the parties responsible for quality decisions and the laboratory should determine the applicable basis before testing; do not choose conditions simply because they favour a result. Whether preconditioning is needed, the end condition and the atmosphere during testing must be confirmed against the applicable method and laboratory procedures.
Describe the submitted sample and its history
Identify style, order, colour, size, yarn or fabric lot, garment or specimen part, treatment and finishing condition, and sample version on the request. Record whether it has been washed, pressed, exposed to moisture or otherwise treated in ways that may affect comparison, and whether samples before and after treatment need separate testing. Sample origin, sampling location, quantity and handover should be traceable. If the supplier submits the sample, establish the scope it represents too.
Ask the laboratory about required quantity, packaging, transport and handling on arrival, and explain the purchasing decision the result will support. If condition is unknown, packaging is wet or there are too few specimens, ask the laboratory and both parties to decide whether testing can proceed as agreed and how to record it; do not guess that a sample has returned to a particular condition. Whether colours, lots, processes or specimen parts require separate submissions depends on order requirements, actual differences and laboratory assessment. One result does not automatically represent untested scope.
| Agreement before submission | What to record | If information is missing |
|---|---|---|
| Test object | Sample identity, part, colour, lot and treatment condition | Check with laboratory and retain unconfirmed scope |
| Method and version | Physical or mechanical test method, conditioning basis and applicable amendment | Confirm applicable documents first |
| Atmosphere and end condition | Whether preconditioning is needed, conditioning and testing atmospheres, method's end condition | Ask laboratory for a written explanation |
| Report and decision | Result, atmosphere records, deviations, applicable limits and decision rule | Identify open items and owners |
This table supports discussion; it is not a substitute test procedure. Temperature, relative humidity, permitted ranges and end conditions must be confirmed with the laboratory under the applicable method. Do not copy values from a report for another test or treat a fixed number of hours as a rule for all knitwear.
Distinguish conditioning, flat rest and test conditions
Flat rest can be a preparation agreed by the parties for comparing dimensions or appearance. Without controlling and verifying the atmosphere under the applicable method, however, it cannot be called completed standard conditioning. Conditioning and testing may also be separate stages requiring separate records: ask when specimens enter and leave the specified atmosphere and whether testing occurs under the required conditions. Follow the method if it specifies otherwise; completing the first stage does not automatically establish compliance at the second.
Ask how the laboratory records its atmosphere and confirms the end condition, and what appears in the formal report or traceable records. If the atmosphere is outside requirements, preparation or testing deviates, or the sample's history is unknown, retain the details and laboratory opinion. The relevant parties must decide whether to accept the deviation, prepare again or retest and confirm the effect on cost and timing. Do not attribute a difference directly to conditioning without knowing its cause; yarn, construction, lot, treatment and measurement method also warrant investigation.
Check the report and compare cautiously
Check laboratory name, report number, sample identity and condition, test and method version, conditioning and testing conditions, relevant deviations, result and unit, limits and conclusion. If the report does not provide enough information to establish whether the agreement was followed, ask the laboratory for clarification or relevant records. Not every report must present every detail in the same format. The conclusion applies only to the specimens and agreed scope covered by the report; it does not automatically guarantee the entire order.
Suppose samples A and B are from different lots. A's report states the agreed conditioning and test conditions, while B's report does not state the atmosphere. Do not rank the materials from the two numbers alone or attribute the difference to conditioning. First ask the laboratory to verify B's conditions, method version, sample state and any deviations, then decide whether the results are suitable for comparison. Even if conditions match, retain the fact that the lots differ when interpreting them. This example illustrates an information check, not an actual test result.
If the report states conformity, check the applicable limit and decision rule. NIST's definition of a decision rule concerns how measurement uncertainty is considered in stating conformity. Agree the rule and relevant reporting requirements at commissioning; one value cannot automatically establish a passing conclusion in every case. Other measured properties cannot substitute for the physical test itself. The bulk knitwear receiving and quality claims guide can help plan subsequent discussions.
Prepare the inquiry
Use the WTBF inquiry page to provide a style drawing, material and construction, use, colours and sizes, quantities per style and colour, planned tests and requirements, sample lot and treatment history, existing reports, destination and target timing. Ask the supplier what samples and traceability records it can provide, and confirm method, conditions, cost, sample quantity and report contents with the laboratory. WTBF knit pullovers can be used as style references. Actual testing and purchasing arrangements depend on the parties' agreement.