The Labour Line Missing From Pad Cost Models: Changes Per Shift

Two quotations land on the buyer’s desk. Option A is 0.28 per pad with three changes per tray per shift. Option B is 0.52 per pad with two changes. The buyer compares 0.28 with 0.52 and orders A, saving 46 percent per unit. On 40 trays a shift, three shifts a day, 300 days a year, option A costs 30,240 in pads against 24,960 for option B. The cheaper pad is 5,280 more expensive before anyone touches a tray.

This is the most common arithmetic error in pad purchasing, and it survives because labour is booked to the room rather than to the pad. Here is how to put the missing line into the model, and when the calculation flips back.

What a Pad Change Actually Costs in Seconds

Time a change properly and it is not the twenty seconds of lifting product. It is: locate the tray, lift or slide product aside, peel the spent pad, dispose of it, fit and smooth the new pad, reposition product, and record the change. In a well-organised room that is 40 to 55 seconds. In a room where pads are stored at the other end of the chiller, it is 90 seconds.

At a loaded labour rate of 22 per hour, 45 seconds is 0.275. That is roughly the price of a mid-grade pad, which is exactly why pad count dominates the total.

Running the Numbers on a Real Room

Take 40 trays, three shifts, 300 days. Option A at three changes, 45 seconds each: 120 changes a day, 54 minutes, 19.80 a day, 5,940 a year in labour, plus 30,240 in pads. Total 36,180. Option B at two changes: 80 changes, 36 minutes, 13.20 a day, 3,960 a year, plus 24,960 in pads. Total 28,920.

Option B is 20 percent cheaper overall despite costing 86 percent more per unit. The flip point, where the two become equal, is when the heavier pad costs more than about 1.9 times the light one.

When More Changes Are Actually Cheaper

The model reverses in three situations. Where products have very different drip loads on the same line, a light pad changed twice beats a heavy pad changed once, because the heavy pad is wasted on the beef tray. Where trays are changed at fixed points that already exist in the shift, such as before a break, the marginal labour cost approaches zero. And where the pad is very cheap relative to labour, as in low-wage operations with high tray counts, three changes can win.

What never wins is three changes where two would do because the pad grade was chosen by price. That is not a labour decision, it is an unmanaged one.

The Other Half of the Labour Line

Changing pads is not the only task the grade affects. Spent pad disposal, tray washing and floor mopping all scale with the number of saturated pads and with how often trays run wet. A room running dry trays typically spends 8 to 12 minutes a shift on mopping. A room running wet trays spends 20 to 30, plus a weekly deep clean.

Add 15 minutes a shift at 22 per hour across 300 days and that is 1,650 a year, which is another 6 percent on the pad budget and enough to change the ranking of two quotations.

The right comparison is never price per pad. It is cost per tray per shift, including every touch. Our high-capacity SAP pads that hold a full shift without a change are specified so the labour line stays at one.