The layout of two unit sizes in particular has a strong bearing on the efficiency of the unit mix―namely 5-by-10 units and 7.5-by-10 units. The tendency by many is to situate the unit with the 10-foot dimension along the corridor. This contributes to an inefficient mix. A 5-by-10 unit with the 10-foot dimension along the corridor has a corridor width to unit depth ratio of 5:5, or 1.00, compared to a ratio of 5:10, or 0.50, if the 5- foot dimension is placed along the corridor. This is illustrated in the diagram below.
The difference for the 7.5-by-10 units is not as profound, but when multiplied by 60 or 80 units, it has an impact. The rule that should be applied is the side with the narrower dimension should almost always be the side open to the corridor. The only exception would be when such a layout would result in support columns falling in the middle of a unit door.
Most storage developers and operators strive to maximize convenience for the customer. This strategy includes minimizing the number of turns required from the elevator to any particular unit. An ideal layout requires only two turns from the elevator to access the majority of the units; however, three turns is not an unreasonable number, particularly if the first turn is the one from the elevator.
Some operators prefer a pass-through elevator design. While this is slightly more expensive, it allows a customer to push the cart through the elevators doors on the bottom floor and then, without changing directions, push the cart off the elevator through the opposite doors on the floors above. Most operators that have installed this type of elevator have received favorable comments from customers.
Efficient unit layout requires “banks” of units be no narrower than 20 feet. This allows for back-to-back rows of 10-foot-deep units. At times, the width of a building may challenge this requirement. In such cases, unit sizes can be shifted between floors to arrive at the most efficient overall mix. Also the depth of units against exterior walls can be varied to allow the interior banks to be no narrower than 20 feet. If the spacing still doesn’t work, one trick that may help is turning corridors in the opposite direction.