Evolving pipe joining methods and their association to musculoskeletal symptoms for residential plumbers.

BACKGROUND: Recently the plumbing trade has transitioned from traditional copper piping to flexible plastic piping (PEX) for residential water distribution systems. However, there has been very limited research into the ergonomic implications of the modernized processes. OBJECTIVE: This research documents the physical workload and risks of musculoskeletal disorders (MSDs) with the use of new tools and processes for joining piping. The research also identifies the factors which can facilitate or limit the use of new ergonomically beneficial tools. METHODS: This mixed methods research included workplace observations, interviews, an experiment, a survey of plumbers in residential construction and focus groups with both plumbers and plumbing contractors. RESULTS: Advantages and disadvantages of the various techniques for joining pipes showed that manual crimping has advantages (i.e., productivity and lower cost) that make it desirable for plumbing contractors. Power devices, which were not widely used, have great potential to reduce MSD risks especially if the size and weight of the tools decreases with newer technologies. A continuing barrier is the cost of power equipment. CONCLUSION: The move to provide ergonomically beneficial tools was not as rapid as the willingness to change piping materials. Productivity and costs of tools are barriers to ergonomic interventions.

Functional relationship between ammonia-oxidizing bacteria and ammonia-oxidizing archaea populations in the secondary treatment system of a full-scale municipal wastewater treatment plant.

The abundance of ammonia-oxidizing bacteria and archaea and their amoA genes from the aerobic activated sludge tanks, recycled sludge and anaerobic digesters of a full-scale wastewater treatment plant (WWTP) was determined. Polymerase chain reaction and denaturing gradient gel electrophoresis were used to generate diversity profiles, which showed that each population had a consistent profile although the abundance of individual members varied. In the aerobic tanks, the ammonia-oxidizing bacterial (AOB) population was more than 350 times more abundant than the ammonia-oxidizing archaeal (AOA) population, however in the digesters, the AOA population was more than 10 times more abundant. Measuring the activity of the amoA gene expression of the two populations using RT-PCR also showed that the AOA amoA gene was more active in the digesters than in the activated sludge tanks. Using batch reactors and ddPCR, amoA activity could be measured and it was found that when the AOB amoA activity was inhibited in the anoxic reactors, the expression of the AOA amoA gene increased fourfold. This suggests that these two populations may have a cooperative relationship for the oxidation of ammonia.

Factors affecting the risk of developing lower back musculoskeletal disorders (MSDs) in experienced and inexperienced rodworkers.

Injury and dropout rates during rodwork training appear to reflect difficulties encountered by apprentices adapting to increased physical demands of tying on slab, one of the rodworking tasks with the highest injury risk. Because experience influences work strategies, and consequently the risk of developing musculoskeletal disorders (MSDs), this study aimed to identify differences in work practices associated with tying rebar on slab, potentially relevant to back MSD development, in experienced and inexperienced rodworkers. Fourteen male rodworkers were recruited from either experienced (>2 years experience post apprenticeship), or inexperienced (<6 months experience) groups. Both tied an area with rebar laid on the ground. Trunk flexion/extension angles were measured. L4/L5 moments were estimated from T9 Erector Spinae EMG. Experienced workers were found to spend longer periods of time in trunk flexed postures, with lower peak L4/L5 moments. Our findings revealed practices associated with each group might have different implications on back health.

A comparison of RULA, REBA and Strain Index to four psychophysical scales in the assessment of non-fixed work.

OBJECTIVES: The objective of this study was to evaluate the efficacy of three ergonomic assessment tools (EATs) (RULA, REBA and Strain Index (SI)) in the assessment of non-fixed work through comparison to four occupationally relevant Borg 10 psychophysical scales: Lifting Effort, Grasping Effort, Wrist Discomfort, and Low Back Discomfort. PARTICIPANTS: Fourteen male rodworkers participated in this study. The participants had at least six months experience and had no musculoskeletal injuries in the six months preceding their participation. METHODS: Psychophysical scale and video data were collected while participants performed non-fixed work on construction sites. Psychophysical and EAT outcome measure scores were calculated for a shortlist of tasks. RESULTS: It was found that the perceived Grasping Effort and Wrist Discomfort scales differentiated between the WMSD risks associated with rodworking tasks and SI was found to be more effective than RULA and REBA in the assessment of non-fixed work WMSD risks. CONCLUSIONS: Based on the findings of this study, it is suggested that SI be further evaluated for its ability to assess WMSD risks associated with non-fixed work tasks. SI presents results that have practical application to non-fixed occupations and differentiate between tasks based on the WMSD risks associated with the tasks.

Searching for needles in a haystack: identifying innovations to prevent MSDs in the construction sector.

This study identified innovations that could potentially reduce the risk of MSDs in the construction sector. The action research approach was based on a collaborative model of researchers working with workplace representatives. We searched for innovations being used by construction companies. From a potential database of 125 innovations, the study focused on 20 innovations that varied in their penetration into worksites in the geographical area, represented a variety of trades, and were a cross-section of tools and work organizational processes. It examined the attributes of the innovations, and the barriers to their adoption. The analysis was based on observations of workers, surveys of workers and construction-safety consultants, and company interviews. The study found that innovations were adopted by companies for multiple advantages including productivity and quality, but not necessarily ability to reduce MSD risks, their non-complexity, and cost. The major barriers for adoption were the traditional culture of the construction sector rather than financial ones.

Spreading good ideas: a case study of the adoption of an innovation in the construction sector.

A health and safety association collaborated with two research centres to examine the dissemination of knowledge of an ergonomic intervention by opinion leaders in the construction sector. The intervention was a hydraulic ladder lift that aided with loading and unloading of ladders off van roofs. Thirteen companies, with five to 900 employees, were involved. The van operators informed workmates not employed by their companies but who worked on the same site as them about the intervention. The opinion leaders informed decision makers within their companies which led to commitments to purchase similar units. They also gave presentations at prearranged health and safety meetings, where attendees indicated that they thought the intervention sounded like a good idea. In this way, knowledge of the innovation reached at least 32 more companies and potentially several thousand other employees. The study showed the potential for workplace change to be exponential.

A field study investigating the effects of a rebar-tying machine on trunk flexion, tool usability and productivity.

A field study with a before-and-after experimental design was conducted to evaluate the potential reduction in the risk of musculoskeletal injuries to rodworkers when using an automatic rebar-tying machine. Eleven rodworkers participated in this experiment. All dependent variables (trunk posture, rebar-tying time and responses to a usability questionnaire) were first measured before introducing the rebar-tying machine and then after 3 months of usage all dependent variables were measured again. The results of the study indicated that working with a rebar-tying machine significantly reduced the magnitude, frequency and duration of exposure to awkward trunk posture. Tying time was reduced when participants used the machine. The usability questionnaire indicated that most participants preferred to use the rebar-tying machine for ground-level rebar construction. The field study also revealed that the rebar-tying machine is not limited to the reinforcing trade. The machine can be used for other purposes, such as tying electrical conduit and attaching radiant heat tube to steel mesh. Based on trunk posture exposure, rebar-tying time, usability and transferability, it is concluded that the rebar-tying machine can be an effective tool to reduce the frequency and duration of severe trunk flexion, improve usability and increase productivity among concrete reinforcement workers.

An exploratory study of whole-body vibration exposure and dose while operating heavy equipment in the construction industry.

Whole-body vibration measurements were recorded for various types of heavy equipment used within the construction industry. The purpose of these measurements was to provide more information about the potential levels of whole-body vibration experienced by equipment operators in the construction industry, as well as to identify types of equipment warranting further research. In total, 67 pieces of equipment were tested from 14 different equipment types. Testing took place at various construction sites including corporate, public, and residential work projects. Measurements were made (following the 1997 International Standards Organization's 2631-1 whole-body vibration standards) for 20-minute testing periods using a Larson Davis HVM100 vibration monitor and a triaxial accelerometer. The mobile equipment tested was associated with greater levels of whole-body vibration than the stationary equipment. When whole-body vibration levels were compared to the International Standards Organization's 2631-1 standards, wheel loaders, off-road dump trucks, scrapers, skid steer vehicles, backhoes, bulldozers, crawler loaders, and concrete trowel vehicles exceeded the recommendations based on measured vibration dose values. Further research incorporating larger sample sizes and controlled testing conditions is required to better understand the levels of exposure experienced by operators as well as the amount to which seating, terrain, mobility, and vehicle structure might affect whole-body vibration.