1. Scope

Keywords

Rationale

5. Significance and Use 5.1 Construction workers often face substantial and repetitive physical stresses that lead to musculoskeletal disorders (MSDs), such as lower-back pain, herniated discs, shoulder impingement, rotator cuff injuries, knee pain, and wrist pain [1, 2]. Reinforcing ironworkers (rebar workers) are especially prone to lower-back disorders [3] and other MSDs because of the nature of their work. 5.2 The effects of an exoskeleton as an ergonomic intervention can be evaluated through efficacy studies in controlled laboratory environments, and through effectiveness studies in real-world field conditions [4, 5]. Longitudinal field studies are necessary to measure changes in MSD rates, but they are resource-intensive [4]. Efficacy evaluations can be used to predict the potential success of exoskeletons in the field, provided they simulate field conditions realistically [6–8]. Previous research has shown stronger exoskeleton effects in the lab than in the field due to inadequate simulation of real-world conditions [7, 8]. 5.3 This test method focuses on evaluating the efficacy of back-support exoskeletons (BSEs) for rebar workers assembling slab reinforcement, a critical area for two main reasons. First, reinforced concrete is one of the most frequently used construction materials [9] and many buildings, bridges, and infrastructure with a concrete construction require slab reinforcement. As an example, approximately 39% of bridges in the U.S. are made of traditional reinforced concrete, all of which required the assembly of slab reinforcement [10]. The international construction of new reinforced concrete buildings, bridges, and other infrastructure in the coming decades makes rebar workers an essential part of the global work force, and the construction of slab reinforcement an essential project type of the trade. Second, the majority of ergonomic risk in the rebar trade regarding lower-back disorders (LBDs) comes from manual material handling of rebars and from tying rebar intersections in slab construction [3, 11, 12]. Compared to other tasks in other construction trades, the project type of assembling slab reinforcement entails a set of tasks with a unique combination of postural, repetitive, and force related ergonomic risk factors: repeated cycles of a prolonged forward bending posture directly followed by heavy MMH [13]. Biomechanical studies on rebar workers suggest that the combination of tying slab reinforcement with heavy MMH may contribute to the high incidence rates of lower-back MSDs faced by the rebar worker trade [13]. 5.4 Compared to other test methods for evaluating exoskeletons, for example, F3523 Test Method for Exoskeleton Use: Confined Space: Horizontal Movement, the current test method is trade-specific, and therefore provides realistic conditions in which to evaluate an exoskeleton’s efficacy. As described in Section 1, this realism increases the correlation between efficacy and potential effectiveness. More general practices and test methods can be used in tandem with trade-specific test methods, for example Practice 3443 to consider load handling when using an exoskeleton and Test Method F3523 to evaluate an exoskeleton’s performance in confined spaces, which can be applicable to the rebar trade. In this way, an exoskeleton’s efficacy can be comprehensively evaluated for the rebar trade. 5.5 Additionally, the test method is in a simulated environment which reduces concerns of safety and hazards compared to a construction site environment.