Machine safeguarding: Theory, practice, and case studies

Abstract

A machine is a device that uses energy to perform some type of useful mechanical work. Therefore, it must have at least one (and more often many) moving parts. A safeguard is a measure taken to protect someone from physical harm. The sources of harm from a machine typically stem from moving parts and/or electric current. Effective machine safeguards substantially reduce personnel exposure to these hazards and/or the resulting harm, and, as a result, optimize machine productivity. A common image that comes to mind in regard to a machine safeguard is a physical barrier that prevents a worker from inadvertently placing a body part into a hazardous space of a large industrial machine. While this is one important aspect of machine safeguarding, it is a much broader topic that requires a more in-depth analysis to achieve the goal of ensuring personnel safety without unduly compromising machine productivity. Different types of machine safeguards will be discussed in this paper. The safeguarding hierarchy will be presented, which is a guide to determine what safeguarding method(s) should be employed. Case studies of injuries that were caused, at least in part, by various machine safeguarding deficiencies will be presented. Relevant matters that arose during an OSHA National Emphasis Program on Amputations audit at a manufacturing facility will also be discussed. These topics will provide insight on how to better develop and employ more effective machine safeguards.