This document describes a Human Factors Tool that may be used by operating plants as an aid to incorporate human factors principles in the design of equipment that will be operated and maintained by people. The human factors principles described in this document are intended for new equipment designs; however, many ideas provided in this Tool may be used to improve the operation of existing plants, where feasible. This document focuses only on equipment design. Items such as human error, behavior-based safety, and operating procedure issues are not in the scope. The Tool covers equipment that is common to both upstream producing and downstream manufacturing operations. Equipment associated with specific activities, such as drilling rigs is not specifically addressed.