Piedmont Ergo

ergonomicsWe provide workplace solutions for your companies troubled areas to help reduce worker injuries and insurance cost. Whether you are bringing parts to or from an assembly line or moving rolls or boxes, we can provide a solution for you.

An ergonomic Injury and Illness Prevention Program to address MSD hazards should be incorporated into the daily company operations. OSHA recommends that operators lift no more than 50 pounds repetitively but a lot of companies set their limit at 35 pounds repetitive for an 8 hour shift.

Prevention of Musculoskeletal Disorders in the Workplace

Musculoskeletal disorders (MSDs) affect the muscles, nerves and tendons. Work related MSDs (including those of the neck, upper extremities and low back) are one of the leading causes of lost workday injury and illness. Workers in many different industries and occupations can be exposed to risk factors at work, such as lifting heavy items, bending, reaching overhead, pushing and pulling heavy loads, working in awkward body postures and performing the same or similar tasks repetitively. Exposure to these known risk factors for MSDs increases a worker’s risk of injury.

Ergonomic Workstation Equipment increases productivity and reduces the number and severity of work-related MSDs.

Impact of MSDs in the Workplace

Work related MSDs are among the most frequently reported causes of lost or restricted work time.

  • In 2011, the Bureau of Labor Statistics (BLS) reported that industries with the highest MSD* rates include health care, transportation and warehousing, retail and wholesale trade and construction.
  • According to BLS, the 387,820 MSD cases accounted for 33% of all worker injury and illness cases in 2011.

A Process for Protecting Workers

Employers are responsible for providing a safe and healthful workplace for their workers. In the workplace, the number and severity of MSDs resulting from physical overexertion, as well as their associated costs, can be substantially reduced by applying ergonomic principals and workstation equipment.

Implementing an ergonomic process has been shown to be effective in reducing the risk of developing MSDs in industries as diverse as construction, food processing, office jobs, healthcare, beverage delivery and warehousing. The following are important elements of an ergonomic process:

  • Provide Management Support – A strong commitment by management is critical to the overall success of an ergonomic process. Management should define clear goals and objectives for the ergonomic process, discuss them with their workers, assign responsibilities to designated staff members, and communicate clearly with the workforce.
  • Involve Workers – A participatory ergonomic approach, where workers are directly involved in worksite assessments, solution development and implementation is the essence of a successful ergonomic process. Workers can:
    • Identify and provide important information about hazards in their workplaces.
    • Assist in the ergonomic process by voicing their concerns and suggestions for reducing exposure to risk factors and by evaluating the changes made as a result of an ergonomic assessment.
  • Provide Training – Training is an important element in the ergonomic process. It ensures that workers are aware of ergonomics and its benefits, become informed about ergonomics related concerns in the workplace, and understand the importance of reporting early symptoms of MSDs.
  • Identify Problems – An important step in the ergonomic process is to identify and assess ergonomic problems in the workplace before they result in MSDs.
  • Encourage Early Reporting of MSD Symptoms – Early reporting can accelerate the job assessment and improvement process, helping to prevent or reduce the progression of symptoms, the development of serious injuries, and subsequent lost-time claims.
  • Implement Solutions to Control Hazards – There are many possible solutions that can be implemented to reduce, control or eliminate workplace MSDs.
  • Evaluate Progress – Established evaluation and corrective action procedures need to be in place to periodically assess the effectiveness of the ergonomic process and to ensure its continuous improvement and long-term success. As an ergonomic process is first developing, assessments should include determining whether goals set for the ergonomic process have been met and determining the success of the implemented ergonomic solutions.

NIOSH Work Practice Guide for Manual Lifting

In 1981, NIOSH developed an equation to assess lifting conditions. In 1991, NIOSH issued a revised equation for the design and evaluation of manual lifting tasks. The 1991 equation uses six factors that have been determined to influence lifting difficulty the most, combining the factors into one equation. Two of the factors which are new to the revised equation include twisting (asymmetry) and the quality of the worker’s grip on the load (coupling). Using the equation involves calculating values for the six factors in the equation for a particular lifting and lowering task, thereby generating a Recommended Weight Limit (RWL) for the task. The RWL is the load that nearly all healthy employees (90% of the adult population, 99% of the male and 75% of the female workforce) can lift over a substantial period of time (i.e., up to 8 hours) without placing an excessive load on the back.

The revised equation also incorporated a term called the Lifting Index, which is defined as a relative estimate of the level of physical stress associated with a particular manual lifting task. The estimate of the level of physical stress is defined by the relationship of the weight of the load lifted divided by the recommended weight limit. A level greater than one indicates that the lifted weight exceeded the RWL and should be addressed using either administrative or engineering controls. A level greater than three indicates that the lifted weight exceeds the capacity to safely lift for most of the population, is likely to cause injury, and should be modified by implementation of engineering controls.

The 1991 equation still maintains the 1981 biomechanical criteria for establishing the maximum lower back compression force of 770 lbs. For the revised equation, the load constant was reduced from 90 pounds to 51 pounds. This reduction was driven by the need to increase the minimum horizontal distance from 6 inches to 10 inches (which is believed to be the minimum attainable horizontal distance as measured from the spine during lifting) in the 1991 equation. Aside from this reduction the 1991 revised equation represents only a two-pound reduction from the 1981 version when adjusted for revised horizontal distance.

Application of the NIOSH lifting tasks assumes the following

  • Lifting task is two-handed, smooth, in front of the body, hands are at the same height or level, moderate-width loads (i.e., they do not substantially exceed the body width of the lifter), and the load is evenly distributed between both hands.
  • Manual handling activities other than lifting are minimal and do not require significant energy expenditure, especially when repetitive lifting tasks are performed (i.e., holding, pushing, pulling, carrying, walking or climbing).
  • Temperatures (66-79°F) or humidity (35-50%) outside of the ranges may increase the risk of injury.
  • One-handed lifts, lifting while seated or kneeling, lifting in a constrained or restricted work space, lifting unstable loads, wheelbarrows and shovels are not tasks designed to be covered by the lifting equation.
  • The shoe sole to floor surface coupling should provide for firm footing.
  • Lifting and lowering assumes the same level of risk for low back injuries.
  • Using the Guidelines in situations that do not conform to these ideal assumptions will typically underestimate the hazard of the lifting task under investigation.
The computed values of the Recommended Weight Limit are used by the CSHO as a guide to estimate risk. The numbers by themselves do not identify a hazardous activity. The employer’s incidence of injuries and lack of programs for training, work practice controls, and engineering controls related to lifting are elements used to determine the seriousness of the hazard.

Calculations

Figure VII:1-1. Horizontal Measurement

horizontal measurement

The revised lifting equation for calculating the Recommended Weight Limit (RWL) is based on a multiplicative model that provides a weighting for each of six variables:

RWL = LC x HM x VM x DM x AM x FM x CM

where:

LC = Load Constant (51 pounds)
HM = Horizontal Multiplier (10/H)

Horizontal location of the hands (H): The horizontal location of the hands at both the start (origin) and end (destination) of the lift must be measured. The horizontal location is measured as the distance from the mid-point between the employee’s ankles to a point projected on the floor directly below the mid-point of the hands grasping the object (the middle knuckle can be used to define the mid-point). The horizontal distance should be measured when the object is lifted (when the object leaves the surface).

VM = Vertical Multiplier (1 – (0.0075|V-30|))

Vertical location of the hands (V):The vertical location is measured from the floor to the vertical mid-point between the two hands (the middle knuckle can be used to define the mid-point).

DM = Distance Multiplier (0.82 + (1.8 / D)

Travel Distance of the load (D): The total vertical travel distance of the load during the lift is determined by subtracting the vertical location of the hands (V) at the start of the lift from the vertical location of the hands (V) at the end of the lift. For lowering, the total vertical travel distance of the load is determined by subtracting the vertical location of the hands (V) at the end of the lower from the vertical location of the hands (V) at the start of the lower.

AM = Asymmetric Multiplier (1 – (0.0032A))

Figure VII:1-2. Measure of Asymmetry Angle A

Asymmetry Angle

Asymmetry Angle(A): The angular measure of the perpendicular line that intersects the horizontal line connecting the mid-point of the shoulders and the perpendicular line that intersects the horizontal line connecting the outer mid-point of the hips.

FM = Frequency Multiplier (See Frequency Table Below (Table VII:1-1))

Lifting Frequency (F): The average lifting frequency rate, expressed in terms of lifts per minute, must be determined. The frequency rate can be determined by observing a typical 15 minute work period, and documenting the number of lifts performed during this time frame. The number of lifts observed is divided by 15 to determine the average lifts per minute. Duration is measured using the following categories: Short (Less than one hour); Moderate (1 to 2 hours); Long (2 to 8 hours).