My previous blog illustrated the improved results achieved by ergonomic processes that focus is on reducing the risk factors which cause musculoskeletal disorders (MSDs) and non-value added motions. In order to identify and measure these risk factors, you need a valid, quantifiable method for detecting and determining exposure to, in the case of MSDs, the causative risk factors of awkward posture, high force,and time (long duration or high frequency).
Wouldn’t it be great to have a simple “Ergo Meter” that would quickly provide direct readout that a job task is within or outside the limits of what a person can perform safely? (Where is Ron Popeil when we need him?)
Well, your wait is over.
Several qualitative and quantitative “ergonomic assessment tools” are available on the market today. The trick is to pick a few, effective, and easy-to-use tools to use as your assessment tool kit.
Qualitative assessment tools use visual indicators to identify and record awkward postures and high forces performed in work tasks. These simple checklists and memory cards are a quick way for supervisors and employee teams to screen the work area, and in many cases, find and fix obvious problems with a workstation setup.
Like many professionals, I suffer from ‘Industrial Hygienists Disease’: That is; if I can’t measure it, I don’t know how bad or good the exposure is. This is where quantitative ergonomic risk assessment tools come into play. Just like a noise dosimeter, these assessment tools combine the exposure to awkward posture and high force, with the duration or frequency of exposure, and compare them to the known limits of what the human body can tolerate without damage.
Unlike noise, which affects only one part of the body (the ears), quantitative ergonomic risk assessment tools have to account for the differences in body joints, i.e. wrist vs. elbow vs. shoulder vs. back, etc. Some of these tools evaluate exposures to all joints of the body (e.g. Rapid Entire Body Assessment and Baseline Risk Identification of Ergonomic Factors). Others are specific for exposures to one part of the body (e.g. Rapid Upper Limb Assessment and the NIOSH Lifting Equation).
When choosing the quantitative tools for your assessment tool kit, consider the following attributes:
- Validity: The assessment tool should include a limit value for force and frequency and excessive ranges for posture. To assure validity, look for limits based on at least two independent research studies reported by two independent refereed journals.
- Differentiation: The tool should be able to differentiate exposures between different job tasks and within a job task.
- Reliability: This is the ability to obtain similar results at different times, all other factors being equal. This is dependent to some degree on the person using the tool for follow the correct rules for use, and within the limitation of use.
- Reproducibility: Refers to the ability of different assessors to obtain similar results independently, all other factors being equal.
Know the scope and limitations of assessment tool. Not all risk assessment tools measure exposures on all parts of the body. There are limitations for the applicability of all tools.
3) Quantitative Results:
The tool should provide a valid numerical score measuring exposure to risk factors relative to a threshold or limits for humans. This provides a reference point to determine if the exposure is above or within the capabilities of the human body.
4) Ease of Use
In the workplace, as opposed to a research application, the ergonomic risk assessment tool should be easy to use, identify risk factors and root causes, and determine the level of exposure quickly. The method should not be invasive, interrupt or negatively affect the person being assessed. So portability and ease of use are critical.
In Humantech’s recent benchmarking study with companies with effective ergonomic processes, we found that:
- 85% of participants used a qualitative tool to screen the workplace for ergonomic issues
- Most used an observation-based tool for office and computer self assessments. This enables individuals to complete self-assessments and make adjustments at their own office workstation, reducing the need for assessments by an “expert”.
- 92% of participants used quantitative tools ( tool set of 2-3) to measure the actual exposure to MSD risk factors.
- 69% specified the tool(s) to ensure consistency in reporting and communication, and to simplify training.
- 77% – used employee teams (e.g., Ergonomics Team, Safety Team, ad hoc team) to conduct assessments at non-office job tasks.
- 77% of participants use the risk assessment score to prioritize jobs/tasks to identify and select jobs for improvement.
So where does your organization stand with management of ergonomics?
- Are you using subjective or objective methods for assessments?
- Do you use an “ergonomic dosimeter” to quantify the exposure to MSD risk factors?
- Are your current risk assessment tools valid? Do you trust the assessment findings?
- Are your tools getting you results, or just keeping assessors busy?