Small Shop Layout That Moves Parts One Direction

Why this matters

In most small shops the floor plan was never designed. The parts room went wherever the shelving fit, receiving happens at whichever door the delivery driver chose, and the trucks load at the same door the boxes came in. Every morning, inbound material and outbound material cross paths in one aisle while six techs wait their turn at a counter, and every evening returns get dropped wherever there is floor. The cost does not show up as one line on the P&L. It shows up as trucks leaving late, mis-picks, parts that were received but cannot be found, and the occasional pallet jack meeting an ankle.

The fix is one principle: material should travel one way, from the dock where it arrives to the truck that takes it out, without doubling back or crossing its own path. This card is the floor plan that follows from it. Growing the plan for more people is covered in The Shop Layout That Supports a Growing Headcount, and the morning routine itself in Organizing the Shop for a Faster Morning Load-Out.

The one-way rule, and why it works

A part has a life in the shop: it arrives, gets checked, gets put away, gets picked, gets staged, and leaves on a truck. If each of those happens one step further along the building than the last, three things follow:

• No crossing traffic. People carrying inbound cartons and people carrying outbound picks never share an aisle at the same time, so nobody waits and nobody collides.
• Every zone has one job. A box on the receiving table has not been checked. A box in the parts room has. A box in a staging lane belongs to a route. Location tells you status, which is the simplest inventory control there is.
• Problems surface in one place. A short shipment is found at the inspection table, not on a customer's driveway.

When material has to go backward (returns, cores, warranty parts, a part pulled off a truck), it goes backward on purpose, to a designated returns area at the start of the flow, and usually at a different time of day than the forward flow.

The zones, in order

1. Receiving door. An overhead door or dock where freight arrives, at one end of the building. Ideally not the door the trucks load from.
2. Inspection table. Right inside the receiving door: a table where every shipment is opened, counted against the packing slip and the purchase order, and checked for damage before anything is put away. A part that skips this step becomes an inventory error the first time it is wrong. See related: The Receiving and Putaway SOP.
3. Parts room. The stock, organized by location code. Putaway enters from the receiving side, picking exits toward the staging side. See related: Organizing a Parts Room So Anyone Can Find Anything.
4. Route staging lanes. Marked floor areas, one per truck or route, next to the load-out door, where the next day's parts for each route are set out. A lane is a rectangle of floor tape with a route name, big enough for the largest normal load.
5. Tool crib. Shared and specialty tools signed out and returned. It sits next to the staging lanes because tools are the last thing a tech grabs. See related: How to Set Up a Tool Crib in a Small Shop.
6. Load-out door. Where trucks back up or pull in to load. At the far end of the flow from receiving.

Three areas sit outside the line on purpose:

• Returns and cores. A shelf or cage near receiving, because a returned part must be checked like a new one before it goes back into stock or out for credit.
• Wash bay. Where equipment, hoses, carpet tools, sprayers or pool gear are cleaned. It needs its own door and floor drainage, and that drainage goes where the local sewer authority allows (often through a sediment trap or an oil-water separator), never to a storm drain or onto the lot, because storm drains discharge untreated to surface water and an illicit discharge is a violation under local storm-water rules.
• Office. At the front, beside the visitor door, so customers, applicants and vendors reach it without walking through the shop.

The plan

A small shop of about 60 by 100 feet, drawn with the flow running left to right across the top row:

 rear lot: CYLINDER CAGE, away from doors and drains
+-------------+---------------+------------------+
| RECEIVING   | PARTS ROOM    | STAGING LANES    |
| door D1     | putaway ->    | lane 1 .. lane 6 |
| inspection  | -> pick       | -> load-out D2   |
| table       |               |                  |
+-------------+---------------+---------+--------+
| RETURNS and | WASH BAY      | TOOL    | OFFICE |
| cores shelf | own door D3   | CRIB    |        |
+-------------+---------------+---------+--------+
 street side: visitor parking -> front door -> OFFICE

Material enters at D1, moves right through the parts room, and leaves at D2. Nothing in the top row moves left. Returns come back in at the end of the day and go to the returns shelf at the start of the line, not into the parts room.

The cylinder cage is outside. Compressed gas cylinders and refrigerant are stored away from exits, drains, heat and vehicle traffic, under the fire code as adopted and the rules the cylinder cards cover. See related: Storing Compressed Gas Cylinders at the Shop.

A worked example: one morning, before and after

A shop with 6 service trucks had one front overhead door used for both freight and loading, a parts room against the back wall about 80 feet from that door, and a single parts counter. Every tech picked their own parts at 7:00 a.m.

Before. The owner timed a typical morning. Each tech spent about 6 minutes at the counter getting parts picked and about 5 minutes carrying them to the truck and loading. With one counter, the techs waited in line. The first tech waited 0 minutes, the second 6, the third 12, and so on to the sixth at 30. Total waiting: 0 + 6 + 12 + 18 + 24 + 30 = 90 tech-minutes. Picking took 6 x 6 = 36 tech-minutes and loading 6 x 5 = 30. The morning cost 90 + 36 + 30 = 156 tech-minutes, and the last truck left about 41 minutes after 7:00 (30 minutes waiting, 6 picking, 5 loading). Meanwhile, the morning's first freight delivery came through the same door into the same aisle.

After. The owner moved receiving to a side door at one end, put the parts room in the middle, and taped six staging lanes beside a second overhead door at the other end, with the tool crib next to the lanes. The parts person now picks the next day's parts into the lanes in the afternoon, which takes about 50 minutes. In the morning each tech walks to their own lane, checks the parts against the job list, and loads, in about 8 minutes, all six at once.

• Morning tech time: 6 x 8 = 48 tech-minutes, against 156 before. Saved: 156 minus 48 = 108 tech-minutes a morning, or 1.8 tech-hours.
• Cost: 50 minutes of parts-person time each afternoon.
• Over 20 working days: 108 x 20 = 2,160 tech-minutes, which is 36 tech-hours saved, against 50 x 20 = 1,000 minutes, about 16.7 hours, of parts-person time added.
• Last truck out: about 8 minutes after 7:00 instead of about 41.

The 36 hours are tech hours, the ones that turn into billable work if the schedule fills them; the 16.7 are parts-person hours, a cheaper labor rate doing work that has to be done by someone anyway. Those are two different kinds of hour, and the trade is good because the first kind is the scarce one, not because 36 is bigger than 16.7.

What the layout contributed: the staging lanes need floor area beside the load-out door, about one truck bed's footprint per route, and that space did not exist in the old plan. Afternoon staging is a process; the lanes are the floor plan that makes it possible.

What would change the answer: a shop whose techs carry most stock on the truck and pick only a few special-order parts each morning gains far less, and might keep one door. A shop that receives only a few parcels a day may not need a separate receiving door; a receiving table at one end of the parts room and a rule that freight arrives after load-out does the same job.

Aisles, exits and moving equipment

• Egress paths stay clear. Exit doors, the aisles leading to them, and the space in front of electrical panels and fire extinguishers are not storage, however tempting. Required widths and exit distances come from the building and fire codes as adopted. Mark them on the floor.
• Pedestrians and powered equipment. If a forklift or powered pallet jack runs between receiving and the parts room, mark a walkway beside its path rather than sharing the aisle, and keep blind corners mirrored. See related: How to Decide Who May Drive the Forklift and Pallet Jack.
• Rack along the flow. Pallet rack and heavy shelving run parallel to the flow, so the aisles carry material in the direction it is already going. See related: Rack Load Ratings and the Label Every Bay Needs.
• Charging and flammables. A battery charging area and flammable liquid cabinets sit off the main flow, where their own ventilation and separation rules can be met. See related: Setting Aside a Battery Charging Area.

How to check a plan before moving anything

Draw the building to scale on paper and trace three routes with different colors: a carton from the truck that delivers it to the shelf, a part from the shelf to a service van, and a returned part from the van to wherever returns go. Then look for:

• any place two colors share an aisle at the same time of day;
• any route that doubles back on itself;
• any zone with two jobs, such as an inspection table that is also the returns pile;
• any route that passes through the office, the wash bay, or an exit path.

Each of those is a place the morning will slow down. Moving a shelf on paper costs nothing; moving loaded rack is a weekend.

References

• See related: The Shop Layout That Supports a Growing Headcount
• See related: Organizing the Shop for a Faster Morning Load-Out
• See related: Organizing a Parts Room So Anyone Can Find Anything
• See related: Storing Compressed Gas Cylinders at the Shop
• Your local sewer authority's pretreatment rules and the municipality's storm-water ordinance, for wash-bay drainage