Choosing uniform fabric for a humid-school order
A women's self-help group in Bankura has won a contract for 300 school uniforms for children aged 11–15. Each uniform needs 2.0 m of 112 cm fabric. Supplier A offers 100% cotton poplin (40s) at ₹120/m with laboratory shrinkage of 3.5% warp and 2% weft, colourfastness to washing of 3–4, and no pre-shrinking. Supplier B offers 67/33 polyester-cotton at ₹95/m with 1% shrinkage and colourfastness of 4–5, but lower air permeability. The group has budgeted ₹230 per uniform for fabric. The school wants an indigo colour, and the monsoon in the district is humid; the children wash uniforms daily. The group can pre-shrink fabric by washing before cutting, but that adds ₹6 per metre and two days. A 2.0 m length is the cut length before any shrinkage allowance. The group must decide which fabric to buy and how to handle shrinkage without exceeding the budget or delivering undersized uniforms.
1. Recommend Supplier A or B for this order. Show cost per uniform, the effect of shrinkage, and at least two non-cost factors in your reasoning.
Read the worked answer
Start with the budget calculation, not with fibre preference. Supplier B: 2.0 m × ₹95 = ₹190 per uniform, which is ₹40 below the ₹230 budget. Supplier A: 2.0 m × ₹120 = ₹240, already ₹10 over budget before shrinkage. If the finished length must remain 2.0 m, the cut length for A is 2.0 ÷ (1 − 0.035) = 2.073 m, costing about ₹249; B needs 2.0 ÷ 0.99 = 2.02 m, about ₹192. So B fits the budget and A does not, unless the price is renegotiated to roughly ₹110/m or below. Non-cost factors still matter. B has better colourfastness (4–5) and lower shrinkage, which suits daily washing and indigo shade retention. A has better air permeability and moisture comfort, which matters in humid Bankura and for children aged 11–15. A is not automatically the better choice because “cotton” sounds cooler; the 67/33 blend may feel warmer and hold odour. A defensible decision is to choose B for cost, shrinkage and colourfastness, subject to a wear trial with two or three children; if the school rejects the blend on comfort grounds, negotiate A to ₹110/m or ask the school to raise the fabric budget to about ₹250.
2. What fabric tests and acceptance limits should the group apply before paying for the bulk roll, and how should a sample garment be used?
Read the worked answer
The group should not rely on the supplier's statement alone. Before bulk payment, ask for a 1 m sample from the actual roll and test: dimensional change after washing at 40°C and line drying (measure warp and weft before and after, calculate percentage); colourfastness to washing and to rubbing using a grey scale; fabric weight (GSM) and thread count to confirm the specified poplin or blend; and shade consistency between the sample and the bulk roll. Practical acceptance limits for this order could be shrinkage no more than 2% for B or 3% for A if pre-shrunk, colourfastness at least 4, no visible shade variation between rolls, and no skew or bowing greater than 2%. Then make one complete sample uniform, wash it three times the way the children will wash it, dry it, press it and check the measurements against the size chart and the fit on a child. The sample garment is the real acceptance test: if the washed sample shrinks beyond limits, twists at the side seams or fades, reject the roll or renegotiate. Record the results so the group has evidence if the supplier disputes the claim.
3. If only Supplier A is available, how should the pattern and cutting plan be adjusted? Give a numerical shrinkage allowance and explain why simply adding 3.5% to the length is not enough.
Read the worked answer
If only A is available, treat shrinkage as a cutting constraint. To finish at 2.0 m after 3.5% warp shrinkage, cut length = 2.0 ÷ (1 − 0.035) = 2.073 m, an addition of about 7.3 cm, not 7.0 cm. Adding 3.5% of 2.0 m gives 2.07 m, which looks close but is based on the finished length rather than the cut length; the error grows on longer garments and ignores width shrinkage. The weft shrinkage of 2% reduces the usable 112 cm width to about 109.8 cm, so the marker must be planned on the shrunken width, not the original. Add a small safety margin, say 1%, giving a cut length of about 2.09 m. Better still, pre-shrink the roll by washing, drying and pressing before cutting; that adds ₹6/m, about ₹12 per uniform, so the fabric cost becomes roughly ₹252, above the ₹230 budget. The group must then renegotiate the price, reduce wastage, or accept a lower margin. Cut a washed test square first and adjust the final allowance from measured results, not from the supplier's average.