Sewage Treatment Valve

Task
Operating valves located 7 - 8 feet from floor level in a sewage treatment plant

Problem
Workers need to "exercise" valves once a week, even when located in difficult to reach locations. To make it easier to reach, workers replaced the hand wheel of one valve with a long wrench, since it needs to be moved only one-quarter turn. However, risk factors of awkward postures of the shoulder, neck, and trunk remain. Low force is required for this valve.

Intervention
Install a rocker arm on the valve with a length of chain hanging in a loop. One side of the loop can be pulled to operate the valve one-quarter turn. The chain is much easier to reach than either the hand wheel or the wrench.

Cost
$50 in parts

Evaluation of Intervention

  • Pros
  • Improved trunk and shoulder posture
  • Low cost, easy installation
  • Cons
  • Neck posture still extended (for brief period of time).

Semi-Quantitative Evaluation of Intervention

  • Reduction of Identified Risk Factor
  • No New Risk Factors Introduced
  • Productivity not Reduced
  • Low Cost
  • Total
  • 4/5
  • 5/5
  • 5/5
  • 5/5
  • 19/20

Other Possible Interventions

  • Install pneumatic or electrically powered valve operator with remote actuator (cost > $1000).
  • Reroute pipes and/or relocate valves to allow better access to valves.

Acknowledgements
Union Sanitary District, Union City, CA; and Ira Janowitz, PT, CPE - UC Ergonomics Program