Conducting an ergonomic risk assessment is a foundational element of the ergonomic process. Your ergonomic improvement efforts will never get off the ground without being able to effectively assess jobs and tasks in your workplace for musculoskeletal disorder (MSD) risk factors.

What are the primary ergonomic risk factors? Watch the video below for an overview:

Systematically conducting ergonomic risk assessments gives you a clear view of the risk present in your workplace. This clear view of MSD risk factors will allow you to effectively communicate, prioritize, and implement workplace improvements.

Because ergonomic assessments are the backbone of your ergonomics process, it’s important to be effective and efficient with your assessments, and that all starts with strategically planning your risk assessment efforts.

Planning Ergonomic Risk Assessments

If your ergonomic process is new, you’re likely wondering where you should get started with risk assessments.

We recommend prioritizing departments and jobs to evaluate based on:

• an initial worksite tour
• a review of injury and MSD history
• data and information collected from employee surveys

Levels of Ergonomic Risk Assessment

There are three basic levels of ergonomic risk assessment:

1. Hazard Recognition: A quick screen for MSD hazards at the job level
2. Simple Risk Assessment: A more in-depth screen identifying specific ergonomic risk factors for each body segment at the job level
3. Objective Assessment: A detailed, objective assessment of a job task using a fully quantitative tool

Time and effort required to complete these assessments increases as you progress from hazard recognition to simple risk assessment to objective assessment.

When planning your ergonomic risk assessments, keep in mind that in order to be as efficient as possible you want to minimize the resources required to make a decision on an MSD hazard.

The goal, after all, is to control hazards by making improvements to the workplace, not necessarily to get the most accurate assessment score as humanly possible. Your approach and the tools you use for assessments should reflect this goal.

Hazard Recognition

The goal of the hazard recognition assessment is simply to identify and document the known presence of observed MSD hazards.

The basic MSD hazards are:

• High forces exerted by workers
• Awkward postures
• High repetition
• Vibration
• Contact stress
• Cold temperatures

A hazard recognition tool can be used during your initial worksite tour and also on an ongoing basis as MSD hazards are observed by supervisors, employees, engineers, and the safety/ergonomics team.

Simple Risk Assessment

The goal of the simple risk assessment is to identify and document levels of MSD risk exposure for each segment of the body, resulting in an overall MSD risk score at the job level as well as a list of tasks for further evaluation using an objective tool.

Objective Assessment

The goal of an objective assessment is to quantify exactly the MSD risk exposure present in a job task.

Valid objective assessment tools include:

• NIOSH Lifting Equation
• WISHA Lifting Calculator
• Rapid Entire Body Assessment
• Rapid Upper Limb Assessment
• Snook Tables

NIOSH Lifting Equation

The NIOSH Lifting Equation is a tool used by occupational health and safety professionals to assess the manual material handling risks associated with lifting and lowering tasks in the workplace. This equation considers job task variables to determine safe lifting practices and guidelines.

The primary product of the NIOSH lifting equation is the Recommended Weight Limit (RWL), which defines the maximum acceptable weight (load) that nearly all healthy employees could lift over the course of an 8 hour shift without increasing the risk of musculoskeletal disorders (MSD) to the lower back. In addition, a Lifting Index (LI) is calculated to provide a relative estimate of the level of physical stress and MSD risk associated with the manual lifting tasks evaluated.

WISHA Lifting Calculator

Developed by the Washington State Department of Labor and Industries and based on NIOSH research related to the primary causes of back injuries, this lifting calculator can be used to perform ergonomic risk assessments on a wide variety of manual lifting and lowering tasks, and can be also used as a screening tool to identify lifting tasks which should be analyzed further using the more comprehensive NIOSH Lifting Equation.

Rapid Entire Body Assessment

This tool uses a systematic process to evaluate whole body postural MSD and ergonomic design risks associated with job tasks. A single page form is used to evaluate required body posture, forceful exertions, type of movement or action, repetition, and coupling. A score is assigned for each of the following body regions: wrists, forearms, elbows, shoulders, neck, trunk, back, legs and knees. After the data for each region is collected and scored, tables on the form are then used to compile the risk factor variables, generating a single score that represents the level of MSD risk.

Rapid Upper Limb Assessment

This diagnostic tool assesses biomechanical and postural load requirements of  job tasks/demands on the neck, trunk and upper extremities. A single page form is used to evaluate required body posture, force, and repetition. Based on the evaluations, scores are entered for each body region in section A for the arm and wrist, and section B for the neck and trunk. After the data for each region is collected and scored, tables on the form are then used to compile the risk factor variables, generating a single score that represents the level of MSD risk.

Snook Tables

The Liberty Mutual MMH Tables (commonly known as Snook Tables) outline design goals for various lifting, lowering, pushing, pulling, and carrying tasks based on research by Dr. Stover Snook and Dr. Vincent Ciriello at the Liberty Mutual Research Institute for Safety. The tables provide weight/force values, for specific types of tasks that are deemed to be acceptable to a defined percentage of the population. This is done by comparing data for each of the specific manual handling tasks against the appropriate table.

Don’t Forget the Ultimate Goal of Your Ergonomic Process!

Identifying risk factors at your worksite is just the beginning. Systematic workplace improvements that impact the key safety, productivity, and quality metrics you track is the goal. Make sure you build these efforts on a solid foundation with effective and efficient ergonomic risk assessments.