Costly mistakes in warehouse design

Mistakes in warehouse design differ from other mistakes in one respect: they cannot be corrected, or correcting them is very expensive. Racking can be moved and software replaced, but column spacing, the floor, the number of doors and the footprint of the building cannot be changed once it is built. And the price of such a mistake is paid not in one year but over the 15 to 20 years the building works. That is why it must be found at the drawing stage, not on site.

Mistakes that cannot be fixed after construction

The first group concerns the building structure:

• if column spacing does not match the racking module, space is lost in every row;
• if the floor is not flat enough or strong enough, tall racking and narrow-aisle equipment cannot operate;
• if the fire protection system (sprinklers, compartments) does not suit the stored goods and rack height, the building cannot be used fully; have a specialist check this against the standards;
• ventilation and thermal insulation: in summer in Uzbekistan the inside of a metal-panel building gets hot, which is dangerous for food, medicines, electronics and cosmetics.

An example, with illustrative figures. Column spacing is 12 m and a racking bay is 2.8 m. Four bays fit into 12 metres, that is 11.2 m, and the remaining 0.8 m is useless. That is about 7 percent of the row. If the spacing is chosen to suit the racking module, say 11.4 m, there is almost no loss. On the drawing this is a one-minute calculation; after construction it is a loss lasting years. Compare: changing column spacing on a drawing is a few hours' work, whereas moving a column in a finished building means a new structural calculation, reinforcement and a stoppage of the warehouse.

Doors and the yard

The second group concerns receiving and shipping. The commonest mistake is to decide the number of doors by eye.

An example, with illustrative figures. On the busiest day 40 trucks arrive, and unloading or loading each takes 1.5 hours on average. That is 40 × 1.5 = 60 door-hours. For an 8-hour shift you need 60 / 8 = 7.5 doors. Trucks do not arrive evenly, and if doors cannot be more than 75 percent occupied, you need 10 doors. If the design has 5, trucks will queue in the street, drivers will lose time and deliveries will be late. Adding doors later is not easy either: the wall, the dock and the yard were not planned for it.

Check other points too: does the dock height match the truck body, is there room for a long trailer to turn in front of the warehouse, does the queue of trucks spill onto the road, do the receiving and shipping flows cross at the same door.

The future and infrastructure

The third group of mistakes is things that are cheap today and expensive tomorrow. Electrical capacity must be enough to charge the batteries of handling equipment. Metal racking dampens wireless signals, so plan network coverage for scanners in advance. Leave one wall of the building "open" for future expansion and work out the load for a mezzanine and an office in advance. Spare ducts for cables and pipes cost little during construction but later mean breaking walls and floors. A reserve of 20 to 30 percent in power and space is often justified.

Places that are rarely considered: a returns and defective goods zone, space for packing materials, a battery room, a rest and changing room for staff.

How to check at the drawing stage

1. "Run" three scenarios over the drawing: the busiest day, the largest delivery, a large picking wave.
2. Draw the routes of handling equipment, pedestrians and trucks in different colours and find the crossings.
3. Check the turning radii of equipment and trucks.
4. Involve warehouse staff in the design review, especially equipment drivers and pickers: they know what the drawing does not show.
5. Show the drawing to an independent warehouse specialist before construction starts.

Conclusion

The price of a design mistake is paid for years along with the building, so a check at the drawing stage is the cheapest insurance. The OmborExpert specialists review a warehouse design before construction from the viewpoint of flows of people, volume and future growth, and give the manager a clear conclusion.