Conduit Order Under a Per-Run Cutting Rule
Your crew is roughing in 14 identical home-run conduit runs of 3/4 in. EMT in a parking garage. Each run measures 38 ft from box to box, and the foreman requires 10 percent added for bends, offsets, and mis-measures. EMT is ordered in 10 ft sticks at $6.85 each, and every stick-to-stick joint needs one set-screw coupling at $1.40. Each run is supported by 2 strut straps at $3.25 each. The foreman's standing rule is that each run must be cut from its own bundle of sticks - offcuts are not carried from one run to the next, because the crew works from two scissor lifts on opposite sides of the deck and cutoffs get lost or mixed up. The material budget for conduit, couplings, and straps is $800.00. The supplier offers 12 percent off the list price of EMT when a single order is 60 sticks or more; couplings and straps are never discounted. You must submit the order and tell the foreman whether the budget holds.
1. Under the foreman's per-run rule, how many 10 ft sticks must be ordered? How many would be needed if offcuts could be shared between runs, and why do the two answers differ?
Read the worked answer
Per run: 38 ft × 1.10 = 41.8 ft of conduit required. Since sticks are 10 ft and a run cannot borrow from the next bundle, divide and round up: 41.8 ÷ 10 = 4.18, so 5 sticks per run. 5 × 14 = 70 sticks.
Shared-offcut method: 14 × 41.8 = 585.2 ft total; 585.2 ÷ 10 = 58.52, so 59 sticks.
The difference is 11 sticks. Rounding is applied 14 times under the foreman's rule instead of once, so each run's 8.2 ft of leftover is thrown away: 14 × 8.2 = 114.8 ft of waste, about 11.5 sticks. Rounding position, not the math, drives the quantity.
2. Compute the couplings, straps, and total cost, and state whether the $800 budget holds and by how much.
Read the worked answer
Couplings: 5 sticks in a run create 4 joints, so 4 per run × 14 runs = 56 couplings. 56 × $1.40 = $78.40.
Straps: 2 per run × 14 = 28 straps. 28 × $3.25 = $91.00.
Conduit: 70 × $6.85 = $479.50.
Total: 479.50 + 78.40 + 91.00 = $648.90. Budget is $800.00, so it holds with $151.10 remaining. A useful check: the couplings follow from the stick count, so if someone orders 59 sticks by mistake the coupling count drops to 56 − 14 = 42 and the order is internally inconsistent with the cutting plan.
3. The supplier's 12 percent discount needs 60 sticks. Does the order qualify, what is the new total, and does the discount change the argument for the per-run rule?
Read the worked answer
70 sticks ≥ 60, so the discount applies: $479.50 × 0.88 = $421.96. New total: 421.96 + 78.40 + 91.00 = $591.36.
Does it rescue the wasteful method? Compare conduit cost only. Discounted 70 sticks cost $421.96; 59 sticks at list cost $404.15. The per-run order is still $17.81 more expensive, and 59 sticks would also miss the 60-stick threshold by one, so it earns no discount at all. Conclusion: the discount is a real saving against the same 70-stick order, but it does not make the per-run rule cheaper. The rule is justified by the two-lift logistics and lost cutoffs, not by price.