Using volume: height is floor space too

A lease states square metres, but what you really pay for is volume: all the air up to the roof comes with the building. If a building is 9 metres high and goods are stacked only to 4 metres, more than half of the paid-for volume stands empty. That is why height should be counted like floor area: it is a second, and often the cheapest, place to store things.

What limits height

The height of a building's wall and its usable height are not the same. The height that is fit for goods is limited by the following:

• the lowest point of roof beams, trusses and light fittings;
• the fire suppression system: there must be clear space below the sprinklers above the racking and goods, and the exact value should be checked against fire safety rules;
• the load capacity of the floor: tall racking puts a heavy load on the uprights;
• the lifting height of the equipment and the aisle width;
• the strength and anchoring of the racking. In an area with a risk of earthquakes this is designed separately and handled with a certified installer;
• the goods themselves: whether the bottom box or pallet can bear the load above.

When viewing a building, look not at the wall height but at the lowest point of the structure. Sometimes trusses, ducts and pipes take a great deal of space from above, while the advertised height is true only at the edge of the wall.

An example: from three levels to five

An example, with illustrative figures. Suppose one pallet level, that is, 1.5 m of goods plus 0.2 m for beam and clearance, needs about 1.7 m. In a building with 6 m of usable height, leaving 0.5 m for sprinklers gives 5.5 m / 1.7 m, roughly three levels. With 9 m of usable height it is 8.5 m / 1.7 m, five levels.

Say the racking occupies 1,400 m² and each pallet takes 1.4 m², so the plan holds 1,000 pallet footprints. At three levels that is 3,000 pallet positions, at five it is 5,000. From the same floor you get 2,000 more pallet positions, a rise of 67 percent. To gain as many extra positions through floor area you would need about 667 more footprints, that is, 933 m² of racking area. Adding aisles, the receiving zone and other support space, at a utilisation ratio of 47 percent, that means about 2,000 m² of new building. Height gives you that area without any new rent.

The cost of height and its drawbacks

Nothing is free. Tall racking needs stronger structures, a reach truck or narrow-aisle equipment, good lighting and often a review of the fire suppression system. Installing tall racking in a leased building requires the owner's written consent: floor loading, the fire suppression system and removal at the end of the lease should be agreed in advance. Picking at the upper levels is slower: equipment must rise and descend, and safety requirements are stricter. The safety of tall racking needs separate attention: guards against equipment impact, plates stating the permitted load, staff training and regular inspection of the racking. A knocked or bent upright is not a minor defect, it affects the strength of the whole row. So distribution matters: place fast-moving goods on the lower levels and slow-moving or bulk-lot goods on the upper ones.

For warehouses with small items there is another way to use volume: a mezzanine (a second-floor platform). It suits piece picking but requires attention to fire safety, escape routes and floor loading.

Practical steps

1. Measure the usable height of the building: at the lowest beam and at the sprinklers.
2. Check the lifting height and aisle width of current or planned equipment.
3. Work out load, anchoring and floor pressure with the racking designer.
4. Agree the design with a fire safety specialist.
5. Distribute goods by level: fast-moving at the bottom, slow-moving at the top.

Conclusion

If you do not use the full height of a building you leave part of the volume you already pay for empty. The OmborExpert specialists help calculate capacity from the usable height of the building and the equipment, and choose an option that is safe and makes economic sense.