Designing Wheeled Equipment: Purchasing Considerations to Achieve Long-Term Ergonomic and Economic Success

Balancing Caster Cost – Up-front Costs, Maintenance and Replacement, and Ergonomic Human Impact Ramifications

balancing ergonomic caster costsFor organizations that rely heavily on wheeled equipment in their day-to-day operations (automotive, medical, material handling, etc.), the purchasing department is tasked with making purchasing decisions that impact the design and handling of equipment. The purchasing department’s main goal is to minimize purchasing costs.

This goal can be in direct opposition of other departmental goals. The maintenance department is focused on reducing maintenance and replacement costs. Alternately, there may be someone in human resources whose focus is on reducing injuries and related costs. As a result, organizations’ department heads can often be at odds in determining the best up-front purchasing decision which can lead to a common scenario being played out…

Unable to agree upon which product to purchase, a meeting is called to review each department’s recommendation:

  • The Purchasing Manager advises that the choice is easy because Product A was the lowest cost and was from a vendor that had a proven track record with the company.
  • The Maintenance Department Lead responds that he understands why Product A has a lower cost; his team has replaced this product every 9-12 months when it broke down. The Maintenance Manager recommends Product B because “its rugged design would mean it would maintenance-free for many years which would mean long-term cost savings for the organization.
  • The concern is raised that Product B is more difficult to use and could lead to increased costs from worker fatigue, injuries and insurance surcharges.
  • The Ergonomist, taking into consideration up-front costs, maintenance and replacement costs, and ergonomic impact, recommends Product C as the superior choice, as it provides the balance of these 3 critical areas for the best long-term solution.

Darcor has built its casters around this balanced solution and we call it Ergo-longevity™. We believe that organizations should not focus just on initial cost of the product or purely on maintenance. Organizational leaders who care about the bottom line for the business need to consider both short and long-term costs of casters and consider the ergonomic impact on their valued workers and the oft-overlooked costs of workplace injury.

In their 2007 publication, Ergonomic Guidelines for Manual Material Handling, California OSHA outlined comprehensive approaches to minimize workers’ exposure to physical conditions (e.g., force, awkward postures, and repetitive motions) that can lead to injuries and wastes. The guidelines discuss the key ergonomic considerations for wheeled equipment being minimizing start forces (inertia) and reducing rolling resistance. To move loads with wheeled equipment, the required force is influenced by several factors including:

  • Weight of the load
  • Floor surface condition (i.e., smoothness, cleanliness, and other factors)
  • Slopes and obstacles
  • Wheel materials
  • Size of wheels as larger wheels a minimum of 6 inches in diameter move more easily over holes, bumps, and floor irregularities
  • Maintenance of wheels

These factors address the ergonomic considerations for wheeled equipment with the last point beginning to explore the cost implications. Within “maintenance of wheels”, the California OSHA Guide highlights that inspecting, cleaning, lubricating and/or replacing the wheels on a regular basis are recommended practices. As illustrated in the scenario above, the maintenance department expressed concerns regarding the costs of replacing prematurely worn out, low-cost casters. Wheeled solutions that address the Guide’s ergonomic considerations and provide long-term performance would meet the Ergonomist’s Product C objective.

It’s important to remember that a solution that has a low up-front cost is not going to give the long-term, maintenance-free performance and ergonomic benefits of a higher quality, better engineered and therefore more expensive product.

Case-in-point, a leading automobile manufacturer recently completed a study of casters on production carts to understand the relationship between ergonomics and long-term performance. The study started by identifying several different caster sets that had initial push forces less than 50 lbs as mandated by OSHA. The casters on the carts were regularly inspected and changed and the push-forces were documented.

After 5 years of study, several casters had been eliminated from the test program because of frequent repair requirements. Others remained in-service but had experienced significant increases in their push-forces. Only one set of casters, Darcor’s KP series, maintained the low-effort, push-forces (showing less than 2% change) as determined 5-years earlier. Thus, this Ergo Longevity™ caster has become standard throughout the automobile industry leader’s global facilities.

If you are an organizational leader who would like to learn more about the balance of costs and impact when purchasing casters for your wheeled equipment, check out our caster solutions by industry or contact us to start the process.