Design of warnings for physical tasks: Slips, trips, falls, and manual materials handling (Chap. 53)

11li.s chapter describes the design of warning signs in the do- main of physical ergonomics. The design of effective warnings for hazards regarding musculoskeletal injury requires knowl- edge about potential risk factors and injury mechanisms and should consider the anthropometric , biomechanical , and motor skill abilities of the target population. This information should be integrated with the warning design process as a means of re- ducing costly work.place injuries. Particular emphasis is given to hazards related to slips, trips, falls, and manual material handling tasks . Example prototype w~ are presented . Recommen- dations for future research and application arc offered. WARNINGDESIGN PRINCIPLES AND PHYSICALERGONOMICS Increased attention bas been given to the use of warnings in ad- dressing hazard control in various domains, including consumer products and work environments (Laughe ry & Hammond, 1999). According to Sanders and McCormick (1993), warnings are the last line of defense of a three-pan hierarchy of hazard control. Accoroing to this hierarchy, the first and best method is to design out the hazard. The second-best method is to guard against the hazatd. The third and last method is to use warn- ings . The first two methods are considered the most effective for safety, because if one can design out or effectively control the hazard then individuals are relatively safe without having to do anything themselves to prevent the hazard from causing in- jury (or property damage). However, in many instances , it is not possible to completely eliminate or to adequately guard against all hazards or risks in prod uct usage or task performance. ht those situations , warnings can play an important role as a third line of defense against recognized hazards. Most standards and guidelines for the warning design (e.g., American National Standards htstirote (ANSI), 2002; Wogalter, Conzola , & Smith-Jackson, 2002) generally identify four main textual components : (a) a colo red panel with a signal word and an alert symbol (triangl e surrounding an exclamation point) to attract attention and convey a level of hazard , (b) information Handbook of Warntngs, Edited by Michael S. Wogaltcr, © 2006 , Lawrence Erlbaum Associates (Mahwah, NJ). 655 656 • SHEREHIYET AL. identifying the hazard, (c) an explanation of the potential conse- quences if exposed to the hazard , and ( d) directives for avoiding the hazard. A fifth component is a graphic, such as a pictorial symbol that may assist in conveying one or more of the other four components. Therefore, a warning should convey the level and nature of the hazard present in the situation, how to avoid it, and what could happen if the hazard is not avoided. Research (e.g., Frantz, Miller, & Lehto 1991; Laughery, Vaubel, Young. Brelsford, & Rowe, 1993) recommends that the message text pertaining to the hazard , consequences , and directives should be specific and complete, but also reasonably brief. If needed, the mechanisms of injury involved should be presented to ex- plain the nature of the hazard, including reasons why it is im- portant to comply with the directives (Wogalter et al., 2002). It should also provide directives that can be accomplished ex- peditiously. Not only should the actions named be specific but also they should be relatively easy to perform.