Get insightful content delivered right to your inbox!
Posted by Sadia Waseem
Every manufacturer wants to reduce cost and increase efficiency and the best way to do that is through ensuring worker well-being, which is why it is important for every manufacturer to focus on ergonomics. Fortunately, there are various ergonomic assessment tools today that help manufacturers to improve the safety of their factory floors.
However, the variety of choice makes it difficult to select the right tool.
As Neville Anthony Stanton wrote in his book “Handbook of Human Factors and Ergonomics Methods”:
“There is no one best way or one best tool for conducting ergonomics analyses. Selection of an appropriate technique or tool will depend on the specific application, environment, criticality, required accuracy, learning curve, and cost justification.”
Inappropriate selection of tools can lead to missed risk factors and inefficient modifications, on the contrary the right one will accurately identify ergonomics issues for you along with targeted improvements.
In this article, we will discuss different ergonomics assessment tools along with their application so that you do not have to worry about choosing the right one for your floor. We will also discuss how you can implement these tools easily with an AI powered software.
Before we move on to the specifics, let’s understand the different types of tools and their categories. There are two types of ergonomic assessment tools: qualitative and quantitative. These are further divided by job-level and task-level assessments.
Qualitative ergonomic assessment tools are based on manual observation of a person to identify awkward postures, high loads, and excessive movements of the body. They are quick to use, inexpensive and don’t require extensive equipment but they depend on a person’s observation for results. These types of tools evaluate factors such as the difficulty level of the task, level of exertion, etc. based on perception.
Examples of Qualitative tools:
Some qualitative tools widely used in the industry include:
1. Rapid Entire Body (REBA) Assessment:
REBA assessment evaluates entire body postures to determine the risk areas. It divides the body into segments along with the movement planes to assess the musculoskeletal risks in a variety of tasks. It assigns scores to the trunk, neck, legs, upper and lower arms, trunk, and wrists taking into account load and coupling. High scores means that the job is riskier.
An example application of REBA Assessment:
Scenario: Automotive Assembly – Installing Car Seats
Task: Workers lift the car seats from the cart at the lower height and install them into the vehicles at different heights.
Why REBA: This task involves the motion of the whole body, rapid and dynamic movements along with awkward bending and reaching.
Effectiveness: The study conducted by Ontario University Back Pain Study Group in the automotive industry found high ergonomics risk during seat installation. They conducted a REBA assessment to assess the risk factors. Initially, the score was 11 when placing seats into the cars. After adjusting the height of the car during placement, the score was reduced to 4-6 and there was a significant drop in injury reports.
Kaizen Copilot makes it easier to conduct REBA Assessment. All you need to do is upload the process video in the software and Kaizen Copilot delivers accurate results within a few seconds.
Figure 1: An example of REBA assessment results in Kaizen Copilot
2. Rapid Upper Limbs (RULA) Assessment
RULA assessment is suitable for tasks that involve repetitive motions like data entry, sewing of clothes, etc. RULA is easy and quick to use. It assesses postural loading, particularly on the upper body like arms, wrists, neck, trunk, and shoulders. It also uses a scoring system like REBA for different body parts and scores are directly proportional to the risk factors.
An example application of RULA Assessment:
Scenario: Electronics Manufacturing – Circuit Board Assembly
Task: Use of precision tools to place and solder components into circuits.
Why RULA: The work involves repetitive movements of hand, wrist, shoulders, and neck in a static posture.
Effectiveness: Serratos conducted the research in PCB assembly lines, where initial RULA scores were 6-7 for wrists and 5-6 for neck/shoulders which indicates a high-risk situation. Issues included non-neutral wrist angles during soldering and neck flexion. Adjustable workstations and angled soldering irons reduced scores to 2-3, boosting productivity by 15%.
3. SNOOK Tables
Snook’s psychophysical tables are qualitative assessment tools that have been developed after conducting extensive surveys on workers to find out the amount of load they can handle. The tables provide maximum acceptable weight limits for various percentages of the population (e.g. tasks suitable for 75% of the female population). The tables involve lifting, lowering, pushing, pulling, and carrying activities guidelines for both males and females.
An example application of SNOOK Tables
Scenario: Beverage Factory – Keg (small barrels) Handling
Task: Workers pushed Keg dollies across different floor surfaces.
Why SNOOK Table: This task involves pushing activity, which is only addressed in SNOOK tables.
Effectiveness: Vincent M. Ciriello wrote in International Journal of Industrial Ergonomics that Snook’s psychophysical tables in a brewery highlighted that pushing a 4-keg dolly (225 lbs.) 50 ft on smooth concrete was acceptable to only 25% of male workers. The acceptance rose to 75% on textured rubber matting, The data guided dolly redesign and flooring changes, reducing push forces by 40%.
The ergonomics suite in Kaizen Copilot also supports different activities in SNOOK tables. There are different assessment types available like Snook Pushing, Snook Pulling, Snook Lifting and Snook Carrying. Using Kaizen Copilot can save you from the hassle of finding values from the tables for every task as it is done automatically by the software.
Figure 2: An example of SNOOK Table Result in Kaizen Copilot
Quantitative tools evaluate the factors based on measurements such as distance, weight, count, etc. These tools are for more precise measurements of angles, forces, and other aspects. Quantitative tools often include equipment for precise measurements and thus are more costly.
Quantitative Ergonomic Assessment Tools
An example of quantitative tool is:
NIOSH lifting equation is usually used for manual lifting tasks. The NIOSH Lifting Equation calculates the Recommended Weight Limit (RWL) based on factors such as horizontal distance, vertical distance, lifting frequency, coupling and postures. It incorporates biomechanical, psychophysical, and physiological criteria to determine a weight that nearly all healthy workers can lift over a substantial period without increasing the risk of lower back pain.
An example application of NIOSH Lifting Equation:
Scenario: Distribution Center – Box Handling
Task: Workers lift boxes from pallets at floor level and place them into conveyor at waist level.
Why NIOSH: As the task involves two-handed manual lifting that’s why NIOSH Lifting Equation is recommended.
Effectiveness: Waters applies the NIOSH Lifting Equation in a distribution center. According to his study, the NIOSH Lifting Equation was applied to 78 lifting tasks. For a 40 lbs. box lifted from the floor to 30 inches, the RWL was only 14.7 lbs. due to poor horizontal distance (20″) and high asymmetry (45°). Redesigning pallet placement improved RWL to 25 lbs. making 62% of lifts safe without rotation.
Manual calculation of the NIOSH lifting equation is a time-consuming and complex process as it involves many variables and measurements. Kaizen Copilot takes away all the manual tasks involved in this process and calculates the results within minutes.
Figure 3: An example of NIOSH Lifting Equation result in Kaizen Copilot
2. Hand Grip and Insertion Force:
Hand Grip and insertion force evaluate hand-intensive tasks. The tool combines the activity level of the hand like speed and repetition of task with the peak force exerted by the hand and compares this to recommended threshold values to determine the risk levels.
An example application of Hand Grip and Insertion Force:
Scenario: Appliance Manufacturing – Handle Installation
Task: Workers install handles to refrigerator doors using the power gripping tools.
Why Hand Grip: Hind Grip and insertion forces handle forces in power grips with various tool designs.
Effectiveness: One of the studies by Isa Halim suggested that the power grip tools with longer handles allow the worker to generate more moments by applying a small amount of force. The result was concluded using the hand grip assessment tool. Halim found that the tool handle with a 125 mm length could clamp an object more tightly and had better efficiency with less forearm fatigue compared to an 80 mm length.
Kaizen Copilot also conducts Hand Grip and Insertion Force evaluation and its working is quite similar to REBA and RULA assessment. It evaluates within minutes and provides insightful results.
Figure 4: An example of Hand Grip and Insertion Force result in Kaizen Copilot
Different ergonomic assessment tools are suitable for different tasks, which is why it is important to choose the right one. The best strategy, however, is to use a combination of tools to evaluate all the ergonomics risks present in a workplace and for a better understanding of the situation.
Here are a few factors that you should keep in mind while choosing ergonomics tools for your factory floor:
The selection of tool should be based on the type of tasks and workstations you are analyzing. For example, REBA assessment is suitable for highly dynamic tasks, while the NIOSH lifting equation targets static lifting tasks is mostly common in warehousing. So, it is crucial to have a deeper understanding of your production lines and the physical demands along with material handling operations.
Some of the tools are quite easy to implement and require little training while others require extensive training. Qualitative tools are relatively simpler and can be used with minimal training while quantitative techniques involve complex technical aspects, which need technical understanding and expertise for interpretation.
Assessment methods like checklists, and observation methods only require initial overviews while tools that involve motion captures or postural analysis require in-depth analysis and continuous monitoring of the activity. It is up to you whether you need a quick, bird-view screening or in-depth biomechanical analysis.
Resources required for each ergonomics tools can vary, which impacts their feasibility. Observational methods like REBA, and RULA require minimal resources while the NIOSH Lifting equation measures task variables like horizontal distances and asymmetry angles which is time-consuming, especially for complex lifting scenarios.
You can use systematic approach that utilizes the capabilities of tools to the fullest and meets your workplace goals. A good strategy includes following the process step by step:
You can use quick screening tools that involve subjective surveys for initial monitoring of symptoms and to highlight the areas that require in-depth analysis. When your initial goal is to conduct a screening to recognize the potential risk areas, simple questionnaires and checklists like Body Mapping are a good starting point.
After the initial screening, job analysis tools such as the NIOSH Lifting Equation, REBA, and RULA can provide more in-depth assessments. You can use NIOSH lifting equation for analysis of lifting tasks and REBA and RULA for assessment of working postures which involves rapid movements of limbs.
Several specialized ergonomics tools are designed for specific industries which have distinct workplace demands. SNOOK tables are widely used in manufacturing and material handling operations involving manual lifting, lowering, pushing, pulling, and carrying activities. The WISHA (Washington Industrial Safety & Health Act) Lifting Calculator is a tool specifically designed for construction work environments in Washington state.
Choosing the right ergonomic assessment tool is essential to implementing effective changes on your factory floor. It’s important to align your selections to your requirements. A tiered strategy is effective; begin with general screening tools and go on to more specialized job analysis techniques like NIOSH, RULA, and REBA. Make use of industry-specific instruments such as WISHA for construction or Snook Tables for manufacturing. You can also use a complete toolkit such as Kaizen Copilot that supports all the Ergonomics assessment tools.
Want to make your factory floors safer? Book a demo today.
Brandin and his team help our customers with setting up the Pathfinder platform and getting up-to-speed on all the features and functionalities, in addition to assisting them with standardizing their processes where needed.
Brandin is a seasoned manufacturing leader, who has spent more than a decade designing and setting up assembly lines in both the US and China, optimizing them, and working with human operators to maximize productivity and quality.
Jesse works closely with our marquis customers to understand their needs, and figures out the best solution that immediately adds dollars to their bottom line.
Jesse has two decades of enterprise sales experience. He has held sales leadership roles at pioneering technology startups.
Andrey takes inventions and converts them into innovations. He leads our product engineering team to turn our scientific prototypes into robust customer-facing products.
Andrey co-founded and successfully exited a startup to immigrate to the US. He spent his next eight years building the core data science infrastructure for Amazon’s supply chain planning team, and the CV/ML infrastructure for Microsoft’s HoloLens organization.
Zeeshan focuses on delighting our customers by understanding their needs and defining product and strategy to meet and exceed these needs. He works closely with our sales leadership to grow our customer base.
Zeeshan was a scientific leader at Microsoft’s HoloLens division, where he invented AI technologies to assist frontline workers across industries. Earlier, he shipped IoT platforms and visual defect detection software for manufacturers at Siemens and MVTec GmbH.
Huy takes our product roadmap and figures out what’s achievable with today’s AI advances, and what we need to invent to solve our customers’ pain points.
Huy led teams of scientists and engineers at NEC and invented technologies for driver assistance systems that are part of 500,000+ Honda cars. He is an inventor on more than 20 US patents, and his research papers are cited by every lab from MIT, Stanford, and CMU to Apple, Google, and Baidu.
