How to Set Fabric Tolerances in an RFQ: Width, GSM, Shrinkage, Shade & Decision Rules

A workable fabric tolerance is not a number on its own. It is a complete acceptance rule that states the target, permitted variation, test method, conditioning, sample plan, rounding convention and what happens when a result sits near the limit. B2B buyers should write those elements into the RFQ before comparing offers. Otherwise, two suppliers can quote the same “width,” “GSM” or “shrinkage” while measuring different things.

This guide shows how procurement teams can build an auditable tolerance schedule for bedding and home-textile fabrics. The values themselves must be project-specific: there is no universal commercial tolerance that is correct for every construction, finish, end use or contract.

What is the difference between a target, tolerance and test method?

A target is the intended value, such as finished mass per unit area or usable width. A tolerance defines the permitted departure from that target. A test method defines how the result is produced. All three are needed.

For example, “finished width: ___ cm” is incomplete unless the buyer also defines whether the value means overall width or usable width, the agreed measuring method, the conditioned state, the number and location of measurements, the reporting precision and the acceptance rule. The same logic applies to fabric mass, dimensional change, thread density, shade and performance tests.

Which fields belong in a fabric tolerance schedule?

Specification field	What the RFQ should define	Common ambiguity to remove
Composition	Declared fibre names, percentages where applicable, and the agreed analysis method	A blend name without a disclosed ratio
Construction	Woven/knitted structure, yarn system, face/back, nap or brushed direction	Marketing names used as if they were technical constructions
Usable width	Target, permitted range, whether selvedges are excluded, conditioning and measurement plan	Overall width being substituted for cuttable width
Mass per unit area	Finished-state target, tolerance, conditioning and test method	Greige mass, nominal mass and finished GSM being compared as equivalents
Dimensional change	Preparation, marking, wash/dry procedure, number of cycles, warp/weft reporting and limits	A single “shrinkage” value with no laundering procedure
Colour and shade	Approved standard, viewing conditions, lot/roll rules, instrument settings if used and escalation path	“Match approved colour” without defining the standard or decision process
Surface appearance	Approved physical sample, viewing direction, wash state and named defects or rating method	Subjective words such as soft, smooth or premium
Performance	Named method, specimen direction, conditioning, result unit, limit and decision rule	A test name without an acceptance limit—or a limit without a method

How should buyers set width, GSM and shrinkage requirements?

Usable width

State the minimum cuttable width and whether selvedges, pin marks or distorted edges are excluded. If production yield depends on panel placement, link the width requirement to the cutting marker rather than relying on a nominal loom or overall width. This complements—not replaces—the yield calculation explained in our bedding fabric order-quantity guide.

Mass per unit area

Specify the finished state and conditioning because moisture regain and finishing can affect measured mass. ISO 139 defines standard atmospheres for textile conditioning and testing. The RFQ should also say whether acceptance is based on individual specimens, a roll average, a lot average or another agreed statistic.

Dimensional change

Do not write “shrinkage below ___” without the complete procedure. ISO 3759 covers preparation, marking and measuring; ISO 6330 provides domestic washing and drying procedures for textile testing; ISO 5077 covers calculation of dimensional change. Buyers must still select the relevant procedure, number of cycles, specimen direction and contractual limit for the intended product.

How should shade and visual tolerances be written?

Colour control needs both a reference and a viewing rule. Identify the approved lab dip, strike-off or production standard by revision and date. Define the lighting or instrument conditions, face direction, fold state, backing and whether roll-to-standard and roll-to-roll differences are evaluated separately.

Visual features such as brushed height, jacquard relief, print sharpness and hand feel are better controlled with an identified physical approval sample plus written defect descriptions. A “golden sample” supports communication, but it does not replace measurable requirements. See our golden-sample and change-control guide for revision control.

What is a decision rule, and why does it belong in the RFQ?

A decision rule explains how measurement results—and, where relevant, measurement uncertainty—are considered when declaring conformity. ISO/IEC 17025:2017 is the international standard for testing and calibration laboratories, and ILAC G8:09/2019 provides guidance on decision rules and statements of conformity.

The buyer, supplier and laboratory should agree who makes the pass/fail decision, which rule applies, how borderline results are handled, when retesting is allowed and whether the result applies to a specimen, roll or production lot. A laboratory statement of conformity should not silently become the commercial acceptance decision if the purchase contract uses a different rule.

How can this framework be applied to live Oulai products?

For FAB-0141 Heavyweight Brushed Cotton Jacquard Fabric, the live catalog identifies 100% cotton, jacquard construction and a brushed heavyweight surface for winter bedding. An RFQ should therefore identify the finished mass and usable width, the approved brushed appearance and direction, dimensional-change procedure, and any project-specific thermal or surface test requirements. “Heavyweight” alone is not a thermal-performance result.

For FAB-0701 Polyester–Lyocell Blend Sheet Fabric, the live listing does not publish an exact blend ratio. A buyer should request and approve the fibre percentages before labelling, then define finished width/mass, print or shade approval, dimensional change, surface performance and care validation. Nantong Oulai can discuss custom pattern, colour, width, weight and technical specifications, but every approved value should be recorded in the order specification.

What should a procurement checklist include before quotation approval?

• End use, market and laundering conditions
• Product code, construction and specification revision
• Target value and permitted variation for every critical field
• Finished or greige state, face/back and warp/weft direction
• Conditioning atmosphere and preparation procedure
• Named test method and current agreed edition
• Sampling locations, specimen count and lot definition
• Rounding and calculation convention
• Decision rule, treatment of uncertainty and retest policy
• Approved physical/digital standards and revision control
• Remedy for nonconforming rolls or lots

Only after these fields are aligned should buyers normalize price, usable area and yield across suppliers. Our fabric quotation comparison guide covers that commercial step, while the strength-test selection guide helps match tensile, tear and seam tests to likely failure modes.

Frequently asked questions

Does a test method set the pass limit?

Usually, no. A method explains how to test and report. The buyer and supplier must agree the project-specific requirement unless a governing regulation or product standard supplies one.

Can the supplier choose an equivalent method?

Only if the RFQ permits it and both parties agree how results will be compared. Different methods may use different specimen sizes, procedures and calculations, so their numbers are not automatically interchangeable.

Should tolerance apply to every roll or to the lot average?

The contract must say. An average can hide an unacceptable individual roll, while an every-roll rule may require a different inspection and testing plan.

Does an approved sample replace written tolerances?

No. It is valuable for colour, hand and appearance, but measurable properties and decision rules still need written definitions.

Does a laboratory “PASS” automatically mean the shipment is accepted?

Not necessarily. Confirm the sample identity, method, specification and decision rule, then apply the commercial acceptance terms. Our test-report verification guide explains that evidence check.

Authoritative Sources

• ISO 139:2005 — Textiles — Standard atmospheres for conditioning and testing
• ISO 3759:2011 — Textiles — Preparation, marking and measuring of fabric specimens and garments in tests for determination of dimensional change
• ISO 6330:2021 — Textiles — Domestic washing and drying procedures for textile testing
• ISO 5077:2007 — Textiles — Determination of dimensional change in washing and drying
• ISO/IEC 17025:2017 — General requirements for the competence of testing and calibration laboratories
• ILAC G8:09/2019 — Guidelines on Decision Rules and Statements of Conformity