Fabric Selection for a 40-Shirt School Contract
A tailoring unit has won a contract for 40 white school shirts in a hot, humid district. The school requires daily wear, washing in hard water, and ironing by untrained staff. The unit's pattern uses 1.55 m of 112 cm fabric per shirt before any shrinkage allowance. Two suppliers are available: A, 100% cotton poplin at ₹95/m, one dye lot, minimum cut 5 m; B, 67/33 poly-cotton at ₹70/m, minimum cut 5 m. In the unit's own test (one 40 °C machine wash, line dry), A shrank 4.5% along the warp and 2% along the weft, with wet-rub colourfastness of 3-4; B shrank 1% along the warp and 0.5% along the weft, with wet-rub 4. The fabric budget is ₹6,000, and thread, buttons and interfacing must also come from it. The unit has no steam pre-shrinking facility, only bucket soak and line dry. The school has specified only 'white, comfortable, easy care'.
1. Calculate the fabric requirement and fabric cost for each supplier, and recommend one option with conditions. Show every allowance.
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Consumption. Shrinkage along the warp runs down the length of the shirt, so the warp figure raises length per garment. Supplier A: 1.55 m × 1.045 = 1.62 m per shirt; 40 × 1.62 = 64.8 m, rounded up to the 5 m minimum cut = 65 m. Cost 65 × ₹95 = ₹6,175. Supplier B: 1.55 × 1.01 = 1.5655, round to 1.57 m; 40 × 1.57 = 62.8 m; with a 5 m minimum cut, order 65 m. Cost 65 × ₹70 = ₹4,550.
Recommendation. B leaves ₹1,450 for thread, buttons and interfacing; A is already ₹175 over the fabric budget before trims. Recommend B, but not unconditionally: 67/33 poly-cotton is less breathable and can shine or stick if ironed hot. Specify 40 °C wash, no chlorine bleach, warm iron, and a test shirt worn for two weeks. If the school insists on cotton, A requires either a price increase of about ₹40 per shirt (₹1,600/40) to cover the cost gap and trims, or a negotiated ₹90/m; pre-shrink before cutting by soaking 30 minutes, drying flat, then cutting, and buy 68 m, not 65 m.
2. The school rejects polyester because 'it makes children sweaty'. Present the technical evidence and a workable compromise.
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Polyester is hydrophobic: moisture regain is about 0.4%, against 8.5% for cotton, so sweat stays on the skin and the fabric feels clammy. A 67/33 blend still has only one-third cotton, so it is cooler than 100% polyester but less absorbent than cotton. However, the test results matter: B shrank 1% and had wet-rub 4, while A shrank 4.5% and had wet-rub 3-4; the cotton option will shrink and may transfer colour in hard-water washing. Compromise: offer a 60/40 cotton-rich poplin, if available, at a price between the two; or keep B for daily shirts. Propose 100% cotton only if the school accepts pre-shrinking, a ₹40 per shirt increase, and a care label. Run a two-week wear trial with three shirts of each fibre in the same class, washed together, and let the school judge comfort, shrinkage and colour. State the fibre content and care instructions; do not claim 'breathable' without a test.
3. State the pre-treatment and care label you would use for the recommended fabric, and explain why each instruction is there.
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For B, no pre-shrink is needed for 1% warp, but relax the fabric overnight and cut after checking for skew. Care label: '40 °C gentle wash; do not bleach; line dry in shade; warm iron (max 150 °C); wash dark colours separately.' Reasons: 40 °C limits shrinkage and heat-set creases; chlorine bleach yellows poly-cotton and weakens it; shade drying prevents fading; a hot iron can glaze or melt the polyester; separate washing protects against dye transfer because wet-rub is only 4. For A, if chosen: pre-shrink by soaking in lukewarm water for 30 minutes, spin lightly, dry flat, then cut with the 4.5% length allowance already added; care label '40 °C wash; do not bleach; warm iron; wash before first wear' because of residual shrinkage and size. Stitch a small fibre-content label inside the side seam; in a school contract, the label also protects the unit if a parent washes at 60 °C.