Chlorine Resistance Solutions for Yoga Sets: Specification Checklist
Use this checklist to write chlorine resistance requirements for coordinated yoga sets into a tech pack that a mill can quote against.
Targets to fix before sampling
Write less than 15% modulus loss after 100 hours at 1 ppm chlorine into the pack. Mills quote against the number on the page, so vague language leads to variable results. Because long holds put sustained rather than shock load on the fabric, target checks are made on a worn sample rather than flat fabric alone.
Fabric construction
State structure, composition and finish together. Typical options for this build are soft brushed jersey with 4-way stretch, adjusted to the performance level required. Keep ISO 105-E03 chlorine water named in the tech pack so every lot is measured the same way.

Seam and trim requirements
The problem shows as elastic loss and colour change after pool exposure. Construction choices either remove the cause or hide it for a few washes, so specify the method instead of the outcome. Where coordinated yoga sets is worn for studio practice and everyday wear, set tolerances around that range of movement.
Laboratory to request
Ask for ISO 105-E03 chlorine water on every shade and every size run, not only the approval sample. Any change to soft brushed jersey with 4-way stretch requires re-testing against less than 15% modulus loss after 100 hours at 1 ppm chlorine before bulk is released.
Acceptance criteria
Agree the limit before sampling starts. Re-testing after disagreement costs more than setting the target clearly at the beginning. Past reports from ISO 105-E03 chlorine water help the mill reproduce the same recipe on the next order.