PRODUCT DESIGN: Specific design example

For a specific design example, we have extracted the design of the general size and shape of the standup panels for the control room. This design problem involved many designers, and several design changes occurred during the period over which we observed the project. For this reason, this example is rich enough to allow us to discuss the "ne details of design process. Fig. 1 shows the development of this design along a four-month timeline.

Standup panels are the large panels typically located along the walls of a control room on which meters and controls and alarms are placed. When the "eld study began, an initial design of the panel pro"le already existed.

For ergonomists, one of the main concerns is that controls and meters are readable and reachable. Therefore,

this "rst design was based on anthropometric data provided in the standard IEC-964. Further work with this data set re"ned the design of the panel. The analysis was then documented.

The data used from the international standard, however, was drawn from an American population. Two

months later, speci"c anthropometric data for the customer 's population were received from the customer.

This population's dimensions were somewhat smaller than the IEC-964 data. Accommodating this new data set would have required redesigning the control panels to be shorter by about 1 in (2.54 cm). The changes were considered to be insigni"cant and were noted but not made.

Two weeks later, it was discovered that the current panels would not "t through the hallways of the building,

as designed. For shipping purposes, the panels had to be resegmented. The panels were redesigned so that they could be segmented and shipped through the hallways of the building.

Near the end of August, a design document was issued to the customer illustrating the panel designs. The customer felt that the panels `looked too smalla and, upon learning that the panels were designed to meet anthropometric criteria, established a minimum height requirement for their operators, thereby cutting o! the lower end of the anthropometric data set. The panels were then redesigned to be taller.

The "nal change observed during the "eld study occurred due to a manufacturing consideration. It was decided that the panels would be constructed from mosaic material a modular construction of small blocks covered with plastic that would give #exibility in layout as it would permit modi"cations to be made. The material, although it could be cut, came in "xed sizes, one of which was just slightly larger than the size of the board. To make the manufacture of the panels easier and cheaper, the board was extended once again (Fig. 1).

As illustrated in the example, many practical changes happen during the course of a design. Although ergonomists may strive for the optimal ergonomic design, there are constraints that prevent the locally optimal

ergonomic design from being a globally optimal solution for the design problem.