Wool fabric shrinkage: confirm dimensional stability before cutting

Start with the intended care and garment process

Tell the supplier whether the garment is intended for a particular washing procedure or professional cleaning, and describe any steaming, pressing or preparation before cutting. These are different exposures. A result from one procedure does not establish performance under another. The eventual care instruction must be supported for the selected fabric and finished garment, including linings, interlinings and trims; a fibre name is not a care label.

Read dimensional change in both directions

Ask for the initial and final marked distances in the warp and weft directions, following the agreed method's preparation, conditioning and measurement requirements. Dimensional change (%) = (final distance − initial distance) ÷ initial distance × 100. Under this sign convention, a negative result indicates shrinkage and a positive result indicates growth. Confirm the report's sign convention and units rather than comparing an unsigned “shrinkage” number. This calculation does not replace the complete test procedure.

Define the test rather than asking only for a shrinkage percentage

• For an appropriate washing and drying assessment, ISO 5077 defines dimensional-change determination; the specified washing and drying procedures must also be identified. AATCC TM135 addresses fabric dimensional changes after home laundering.
• Agree the relevant method and edition, cleaning or washing procedure, drying route, number of cycles and conditioning. Do not select home laundering merely because a fabric contains wool.
• Set acceptance limits separately for each direction where needed, and identify the final finish, specimen and production lot.
• If pressing or steaming is part of garment manufacture, evaluate that process separately using an agreed procedure and garment trial. A laundering result alone does not answer a pressing question.

Resolve a failed result before bulk cutting

Check whether the tested specimen received the same finish as the approved bulk fabric. Discuss any proposed stabilising finish, preparation or alternative fabric with the supplier and garment maker, then test the revised version before approval. Recheck handle, appearance and relevant performance after a change. Do not add an arbitrary cutting allowance to hide an unresolved result: fabric, lining and garment construction may respond differently. Fred Textile order requirements and any preparation advice must be confirmed for the specific fabric and end use.