If you fit in regular office chairs, that puts you within “normal” body dimensions – the range of body types that fall between heights of 5’2″ and 6’2″, and weights of 120 to 300 pounds. Office workers who fall outside these outliers, though, are out of luck.

Designing office chairs for the whole range of body sizes may sound simple, but it’s not.  The variation in sizes and dimensions between the opposite ends of the mean suggests that office chairs designed for the “average” human body type causes discomfort to a large subset of the population. Designing office chairs only to the average means that the long tails of the body-fit bell curve – the tall, wide, or diminutive – have to work in less than optimal conditions.

For shorter folk, their feet may dangle from their office chairs, when the OSHA specifies that feet must be able to lay flat on the floor for optimal comfort. For more generously-sized individuals, regular-issue office chairs may be too cramped or permit too little movement.

Over time, the bad fit can become a quality of life problem that affects productivity and increases operating costs needlessly.

Office Chairs That Solve the Problem

To solve the conundrum, facility managers and employees need to exert a little more ingenuity to get the office chairs and system furniture that fit their unique size needs. (Read more)

In their landmark monograph The Anthropometrics of Fit (PDF), Herman Miller followed an “ends-to-the-middle” approach – manufacturing the Aeron in three different sizes “like a bicycle or a pair of shoes” –

- designing the smallest chair for the smallest user, the largest chair for the largest user, and, finally, a midsized chair to cover the range not accommodated by these two. By designing first for the extremes, we developed a chair that gives virtually every person a reasonably good fit, even if it’s never adjusted. The range of fine-tuning adjustment required for each chair becomes both easily manageable and mechanically feasible.

The Aeron office chairs are also designed to automatically accommodate differences in body shape, thanks to self-adjusting material in the seat and backrest. This way, Herman Miller makes a series of office chairs that accommodates 99% of the population, easy.

Other accessories can be included to improve the fit even more – shorter folk, for instance, may need a backrest on their office chairs so their knees can comfortably hang from the edge of the seat pan while providing perfect support for the lumbar area. They may also find a footrest helpful, allowing feet to rest flat on a surface instead of dangle from the edge of office chairs.

Sourcing the Right Office Chairs

A survey of Global Total Office’s stock turns up several office chairs that, like the Aeron, come in three sizes to accommodate the vast majority of the workforce. The “Scale” (PDF) and the “Tritek Ergo” (PDF). For more generous-sized individuals, Global also offers seats that are rated for 350 and 500 pounds, over standard office chairs’ average weight rating of 275 pounds.

Office Star, on the other hand, offers a “Big and Tall” variant on its Pro-Line II product – a deluxe leather executive office chair with adjustable arms, mid-pivot knee tilt, gunmetal finish, all rated for 400 pounds.

The investment involved in buying office chairs that accommodate more than 99% of workers’ body types actually pays off for facility managers – providing a comfortable working environment for extra-large and extra-diminutive workers increases productivity and provides a return on the investment in the long run.