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A step's capacity is sixty times the people on it over the minutes a unit takes, under stated conditions; change the people or the minutes and it changes, and nothing else does.
Paper packet. Every task here also exists on screen, where it is checked automatically; answers written on paper are not assessed by Nydus. When you are back at a device, enter your answers there.
You will compute the most each step can finish in an hour from the minutes a unit takes and the people on it, say which changes move a step's capacity and which do not, and recompute it when a condition changes.
You can map a process as steps and time them. This unit asks how much the process can deliver, starting with each step on its own.
| Term | What it means |
|---|---|
| Capacity | The most a step can finish in a period, under stated conditions. |
| Stated conditions | The people, the minutes a unit, the method and the standard. |
| Minutes a unit | How long one unit takes one person at the standard. |
| Output | What a step actually finished: never more than capacity. |
| Demand | What arrives to be done, which is not capacity. |
| Timing at the standard | Timing ten ordinary units, not the fastest one. |
Capacity is worked out, not remembered from a good day. For one step:
$$\text{capacity per hour} = \frac{60 \times \text{people on the step}}{\text{minutes one unit takes}}$$
At Neighborhood Kitchen, prepping a lunch plate takes 3 minutes and two people do it: 60 × 2 ÷ 3 = 40 plates an hour. Cooking takes 2 minutes a plate with one cook: 30 an hour. Plating takes 1 minute with one person: 60 an hour. Each figure is that step's capacity, with those people, that method, that standard.
Every capacity figure carries its conditions with it, and a change in any of them changes the figure. A second cook doubles the cooking step to 60. A new method that cuts cooking to 90 seconds lifts it to 40. A bigger refrigerator, more orders booked, or a faster register change something else, such as storage, demand or another step, and leave the cooking step's capacity exactly where it was.
Another way: table
Neighborhood Kitchen's lunch steps.
| Step | Minutes a plate | People | Plates an hour |
|---|---|---|---|
| Prepping | 3 | 2 | 40 |
| Cooking | 2 | 1 | 30 |
| Plating | 1 | 1 | 60 |
Another way: steps
Owners often quote a capacity they once achieved: 'we did 200 plates that Friday'. That Friday had four people in, a short menu and nothing going wrong. The worked figure, with today's conditions, is what planning can rest on.
Capacity is also not a target. A step running at its full capacity all day has no room for the unexpected, such as a dropped tray, a phone call or a complicated order, and the next lessons show what happens to the whole process when one step runs out of room. For now, the rule is simply: every capacity figure has its conditions written beside it, so anyone reading it knows what it assumes.
Pick the step. One step from the process map, such as wrapping, servicing or throwing.
Time it properly. Time ten units done at the standard, by the people who usually do it, on an ordinary day. Use the usual time, not the fastest. A cook who once plated in 40 seconds but usually takes 60 has a minutes-a-unit of 1.
Count the people. Only those actually doing this step at the same time. A person who splits their time between two steps counts as a fraction at each, by the share of the hour they spend there.
Divide. Sixty times the people, over the minutes a unit.
Scale to the period. Times the hours for a day, times the days for a week.
Write the conditions. People, method, standard, hours.
Check the figure. Compare it with a real day's output. Output should be at or below capacity; if it is regularly above, the timing was too slow or the standard has slipped. If output is far below, the step is waiting for work, which the next lesson explains.
Dividing sixty by the minutes a unit is allowed because one person working steadily finishes one unit every so many minutes, so in sixty minutes they finish sixty divided by that many. Multiplying by the people is allowed when they work side by side on separate units, each at the same pace.
Timing ten units, not one, is needed because single times vary. The fastest unit is not repeatable; the usual time is what the step delivers hour after hour.
Writing the conditions is needed because capacity is not a property of the step alone. The same oven, with a second cook and a simpler menu, has a different capacity. A figure without its conditions will be used in conditions it does not describe.
The rule assumes each extra person adds as much as the first. Often they do, as with two mechanics on two benches. Sometimes they do not. Two cooks sharing one stove get in each other's way; a third cleaner in a small bathroom adds little. In those cases, time the step with the actual team and use that, rather than multiplying one person's rate.
Equipment can be the limit instead of people. A laundromat's washing step is set by its machines and their cycle time, not by how many attendants are on. A kiln fires a fixed load in a fixed time. Then capacity is the equipment's units over its cycle time, and adding people does not change it.
A day's capacity is rarely the hourly figure times the hours open. People take breaks; equipment is cleaned between batches; a kiln must be loaded and cooled. Subtract these from the hours before multiplying. A kitchen open five hours with a half-hour cleanup between breakfast and lunch has four and a half productive hours, not five.
Changeovers matter most when a step switches between products. A print shop that spends twenty minutes setting up each job loses a third of an hour every time, and a day of many small jobs has far less capacity than a day of a few large ones. Count the changeovers in a typical day and take their time out.
For a service like cleaning or repair, capacity is often counted in jobs or hours rather than units an hour. Bright Home Cleaning has three cleaners working 30 hours a week; a standard clean takes 2 hours; capacity is 3 × 30 ÷ 2 = 45 cleans a week. The constraints lesson in the previous course used exactly this to work out how many new clients fit.
Travel is part of it. A cleaner whose jobs are 30 minutes apart spends half an hour between each two-hour clean, so a 30-hour week holds 12 cleans, not 15. Time the whole cycle, job plus travel, and divide the hours by that.
Capacity turns guesses into plans. If Neighborhood Kitchen's cooking step finishes 30 plates an hour and the lunch rush lasts two hours, the kitchen can promise about 60 plates, not the 80 a busy Friday once managed. If orders for Friday already stand at 70, the owner knows today, not at noon on Friday, that a second cook is needed or that some orders must be declined.
Revisit the figures whenever a condition changes: a new menu item that takes longer, a new hire, a piece of equipment replaced. A capacity sheet that is a year out of date is as misleading as no sheet at all.
Put the figures in one short table: each step, its minutes a unit, its people, its capacity an hour and a day, and the conditions beside them. Add the date the timings were taken. A sheet like this fits on one page and answers most planning questions at a glance: can we take this order, do we need someone extra on Friday, what happens if a mechanic is off?
Keep the original timings too, not only the results. When someone suggests a change, such as a faster wheel or a simpler dish, the timing can be redone for that step alone and the sheet updated, without timing the whole business again. Over a year the sheet becomes a record of how each change moved the business's capacity.
A capacity figure is only honest if the units it counts meet the standard. A cleaner who finishes a bathroom in 20 minutes instead of 30 has not raised capacity if the mirror has streaks and the grout is missed; she has produced a failure faster. Time the step done to the standard, and if a change speeds it up, check the quality before counting the gain.
This is why standard work comes before capacity in this course. Once each step has a written method and a visible standard, its minutes a unit mean something, and a capacity built on them can be planned with.
A food truck in Columbus, Ohio, served lunch from 11:30 to 1:30 at an office park and kept running out of time, not food: a line of 30 people at one o'clock, half of whom gave up. The owner assumed she needed a bigger truck. Instead she timed each step for a week.
Taking an order and payment took about 1 minute with one person: 60 an hour. Cooking took about 3 minutes a meal on two burners, each run by one cook: 40 an hour. Bagging took half a minute: 120 an hour. Over two hours, the truck could serve about 80 people, limited by cooking, while about 110 were turning up.
She did not need a bigger truck. She simplified two menu items so they took 2 minutes to cook, which lifted cooking to 60 an hour and the two-hour lunch to about 120. The line at one o'clock shrank to a few people, and daily sales rose by about a third with the same staff and the same truck.
Manufacturers publish rated capacities for commercial equipment, such as the loads a dishwasher handles an hour or the pizzas an oven bakes. Those figures assume ideal conditions. A business planning from them should time its own equipment in normal use, with loading, unloading and cleaning included, and plan on that figure instead.
Capacity is the best day we ever had. It is worked out from today's minutes and people.
More demand means more capacity. Demand is what arrives; capacity is what can be finished.
Space to wait is capacity. A bigger waiting area holds more work; it finishes none of it.
A capacity figure is true without conditions. Change the people or the minutes and it changes.
Hours open times the hourly rate is a day's capacity. Breaks and changeovers come out first.
Time the step at the standard.
$2 \text{ minutes a customer}$
Ten customers timed.
Count the people.
$2 \text{ people weighing}$
Side by side.
Work out the capacity.
$60 \times 2 \div 2 = 60$
Customers an hour.
Change a condition.
$\text{one helper off sick}$
One person weighing.
Work out the new capacity.
$60 \times 1 \div 2 = 30$
Half, with half the people.
Time ten services.
$40 \text{ minutes a bike, usually}$
At the standard.
Count the mechanics.
$2$
Each on their own bench.
Work out the hourly capacity.
$60 \times 2 \div 40 = 3$
Bikes an hour.
Take out breaks.
$8 - 1 = 7 \text{ productive hours}$
Lunch and a break.
Work out a day's capacity.
$3 \times 7 = 21$
Bikes a day.
Write the conditions.
$\text{two mechanics, standard service, 7 hours}$
So winter is not planned on it.
Note the hours.
$3 \times 30 = 90$
Three cleaners, thirty hours each.
Time a standard clean.
$2 \text{ hours}$
At the standard.
Add the travel between jobs.
$2 + 0.5 = 2.5$
The whole cycle.
Divide the hours by the cycle.
$90 \div 2.5 = 36$
Cleans a week.
Compare without travel.
$90 \div 2 = 45$
Nine cleans overstated.
Write the conditions.
$\text{3 cleaners; 30 minutes between jobs}$
What the figure assumes.
Plan with it.
$\text{36 a week, not 45}$
Before promising new clients.
Time ten mugs at the standard.
$12 \text{ minutes a mug}$
The usual time.
Work out her capacity alone.
$60 \times 1 \div 12 = 5$
Mugs an hour.
Add an apprentice at the same pace.
At Northside Repairs, servicing takes $28$ minutes a bike with one mechanic on it. Which change would double the servicing step's capacity?
Complete the worked solution: at Neighborhood Kitchen, wrapping a lunch takes $5$ minutes, $3$ people wrap, and the wrapping station runs $6$ hours a day. Find how many lunches one person wraps in an hour, the step's capacity an hour, and its capacity a day.
Find one person's lunches an hour.
$\text{sixty} \div (\text{minutes a lunch}) =$ a
Sixty minutes in an hour.
Find the step's capacity an hour.
$(\text{one person's}) \times (\text{people}) =$ c
Everyone wrapping at once.
Find the capacity a day.
$(\text{an hour}) \times (\text{hours}) =$ d
Under the same conditions all day.
Say what the figure assumes.
$\text{these people, this method, no stoppages}$
Conditions written beside it.
Maya is considering changes to her throwing step. Sort each by what it changes.
| Changes the people at the step | Changes the minutes a mug takes | Changes neither | |
|---|---|---|---|
| An apprentice throwing alongside her | |||
| Clay weighed into balls the night before | |||
| A faster wheel | |||
| A new glaze color |
At Monica's Market Stall, customers served go through three steps. picking and weighing takes $2$ minutes a unit with $2$ people on it; taking payment takes $1.5$ minutes with $1$; bagging takes $2$ minutes with $1$. Fill in the most each step can finish in an hour.
| Units an hour | |
|---|---|
| picking and weighing | |
| taking payment | |
| bagging |
At Neighborhood Kitchen, wrapping a lunch takes $6$ minutes and $3$ people do it. Mark how many lunches the wrapping step can finish in an hour.
0 |——————————| 60
Mark the position with a cross, then write the value:
A hand car wash in Seattle has $2$ bays, each with a crew that takes $10$ minutes a car, and is open $10$ hours a day. How many cars can it wash in a day, with every bay working? Fill in each figure on the sheet.
| Amount | |
|---|---|
| Cars an hour in one bay | |
| Cars an hour in all bays | |
| Cars a day |
A laundromat has $10$ washing machines, each taking $30$ minutes a load, and is open $9$ hours a day. Complete the sentence.
The machines can finish c loads an hour, or d loads in a day.
Lesson test: one question per skill, one attempt each, no hints. Your answers are checked when you submit.
Bright Home Cleaning's ironing service has $2$ people, each taking $40$ minutes a basket. One more person joins, working the same way. How many baskets can the step finish in an hour now?
Answer:
You can work out a step's capacity and say what it assumes. Tell someone why 'our best Friday' is not a capacity figure. Next: the one step that limits the whole process.
20. Your turn: Maya's throwing step, step 3
$60 \times 2 \div 12 = 10$
People doubled.