Choosing Shirting for a 1,200-Shirt School Uniform Tender
A Rajasthan school-uniform tender for 1,200 summer shirts specifies light-coloured, durable, easy-care shirting of at least 100 gsm with shrinkage no more than 2%. The supplier offers three qualities at a similar price: (A) 40s plain weave, 110 gsm, mercerised and sanforised; (B) 30s 2/1 twill, 150 gsm, piece-dyed; (C) 40s polyester-cotton 65/35 plain weave, 120 gsm, with an easy-care finish. A trial shirt made from a satin-striped version of quality A developed frayed collar edges, seam slippage at the yoke and a shiny, worn appearance at the cuffs after 12 industrial washes at 60 degrees Celsius. The school wants the shirt to look crisp at the annual day function, and the tailor warns that the twill is too warm for May. The tender committee asks the supplier to justify one choice and to explain why the striped version failed.
1. Rank the three qualities against the tender's criteria and recommend one, stating the evidence you would demand before signing.
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Criteria that actually decide this tender: shrinkage of no more than 2%, abrasion life at collar and cuff under 60 degrees Celsius industrial washing, easy-care/crisp appearance, thermal comfort in May, and colour fastness - not just the 100 gsm floor, which is a minimum and not a target.
Ranking:
- C - 65/35 PC plain weave, 120 gsm, easy-care. Best match: polyester carries the easy-care and crisp look, cotton gives comfort, plain weave gives interlacement and abrasion resistance at a moderate weight, and PC holds shrinkage under 2% without depending on a single finishing step. The real risk is heat retention in May, so insist on 120 gsm rather than heavier, and check pilling (polyester pills), colour fastness to washing and rubbing, and the actual blend percentage.
- A - 40s plain weave, mercerised and sanforised. Correct weave and finish, but 110 gsm pure cotton will abrade and wrinkle first at collar and cuff, and the crisp look at the annual day depends on starch, not on the fabric. Acceptable only at 125-135 gsm poplin with written shrinkage data.
- B - 30s twill, 150 gsm. Most abrasion-resistant, but too warm for May, slower drying and higher cost per shirt.
Evidence before signing: mill test reports for shrinkage after three washes, colour fastness, pilling, and a GSM tolerance of plus or minus 5%.
2. Using weave geometry, explain the satin-stripe failure and state how to build a striped shirt that survives industrial washing.
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Why satin failed. Satin is built on long floats of four or more yarns passing over one. Interlacing points are few and far apart, so:
- Yarns can migrate. Under seam stress at the yoke, warp and weft slide over each other instead of locking - that is seam slippage.
- Floats sit proud of the surface. Abrasion in a 60 degrees Celsius drum wash attacks the raised floats first, fuzzing and then breaking them, which shows as shine and wear at the cuff.
- Cut edges lose yarns easily. At a collar point the short floats pull out of the seam, which is the fraying observed.
Satin is a decorative weave for low-abrasion, dry-clean or gentle-wash garments, not for a school shirt.
How to keep the stripe:
- Use a yarn-dyed stripe in plain weave or a 2/2 matt rib, so the stripe is created by colour, not by float length.
- If a satin band is non-negotiable, confine it to a yoke panel or placket, never to collar, cuff or a stress seam.
- Fuse collar and cuff with a compatible interlining, use 1.5 cm seam allowances, a fine needle (70/10) and a 5-thread safety stitch so the raw edge is enclosed.
- Verify with a seam-slippage test and a 12-wash abrasion trial on a trial shirt before the tender is signed.