- Practice · 6 marks
From-to chart load-distance layout comparison
Short answer
Load-distance score = sum (loads × distance). Present layout P-R-S-Q yields 2,650 load-m/day; proposed P-Q-R-S yields 1,850 load-m/day. The proposed layout reduces material handling by about 30%.
A plant has four departments P, Q, R and S placed in a straight row in four equal slots with centre-to-centre spacing of 10 m. The daily material flow (loads per day, either direction) is: P-Q 40, P-R 10, P-S 5, Q-R 30, Q-S 15, R-S 50. The present order is P, R, S, Q and the proposed order is P, Q, R, S. Using the load-distance score (loads x distance), compare the two layouts.
Method
The load-distance score is , where is the distance between departments along the row. The layout with the smaller score has less material handling. In a row, distance (difference in slot numbers).
Present layout P-R-S-Q (slots 1, 2, 3, 4)
Slots: P = 1, R = 2, S = 3, Q = 4.
| Pair | Loads | Slot gap | Distance (m) | Load x distance |
|---|---|---|---|---|
| P-Q | 40 | 3 | 30 | 1,200 |
| P-R | 10 | 1 | 10 | 100 |
| P-S | 5 | 2 | 20 | 100 |
| Q-R | 30 | 2 | 20 | 600 |
| Q-S | 15 | 1 | 10 | 150 |
| R-S | 50 | 1 | 10 | 500 |
| Total | 2,650 |
Proposed layout P-Q-R-S (slots 1, 2, 3, 4)
Slots: P = 1, Q = 2, R = 3, S = 4.
| Pair | Loads | Slot gap | Distance (m) | Load x distance |
|---|---|---|---|---|
| P-Q | 40 | 1 | 10 | 400 |
| P-R | 10 | 2 | 20 | 200 |
| P-S | 5 | 3 | 30 | 150 |
| Q-R | 30 | 1 | 10 | 300 |
| Q-S | 15 | 2 | 20 | 300 |
| R-S | 50 | 1 | 10 | 500 |
| Total | 1,850 |
Comparison
Saving load-m per day, i.e. reduction. The proposed layout puts the high-flow pairs P-Q, Q-R and R-S next to each other. It is therefore better, though rearranging costs must be compared with the saving.
Answer: Present = 2,650 load-m/day; proposed = 1,850 load-m/day; proposed layout reduces handling by about 30%.
✓ Answer checked by Claude Opus 5.5 (high effort)
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