Analyzing jobs to identify factors associated with risks for MSDs lays the groundwork for developing ways to reduce or eliminate ergonomic risk factors for MSDs.
Controlling exposures to occupational hazards is the fundamental method of protecting workers. Traditionally, a hierarchy of controls has been used as a means of determining how to implement feasible and effective controls. ANSI Z10-2005, Occupational Health and Safety Management Systems, encourages employer employ the following hierarchy of hazard control strategies:
The idea behind this hierarchy is that the control methods at the top of the list are potentially more effective and protective than those at the bottom. Following the hierarchy normally leads to the implementation of inherently safer systems, ones where the risk of illness or injury has been substantially reduced. Let's take a closer look at the hierarchy of control strategies.
Elimination and substitution, while most effective at reducing hazards, also tend to be the most difficult to implement in an existing process. If the process is still at the design or development stage, elimination and substitution of hazards may be inexpensive and simple to implement. For an existing process, major changes in equipment and procedures may be required to eliminate or substitute for an ergonomics hazard. Some obvious examples of elimination include eliminating the need to carry heavy containers by replacing them with smaller containers. You can substitute that old office chair with a new ergonomically designed chair.
These strategies are considered first because they have the potential of completely eliminate the hazard, thus greatly reducing the probability of an accident. Redesigning or replacing equipment or machinery may be expensive, but remember that, according to the National Safety Council, the average direct and indirect cost of a lost work time injury more than $38,000 and most injuries in the workplace are ergonomics-related.
The preferred approach to prevent and control MSDs is to design the job including:
A good match, meaning that the job demands pose no undue stress and strain to the person doing the job, helps ensure a safe work situation.
Engineering controls are preferred because they may completely eliminate the hazard. No hazard: No injury! They also do not rely on human behavior nor do they require continual oversight to work. Finally, engineering controls may save the company far more than the initial investment. Engineering control strategies to reduce ergonomic risk factors include the following:
Work practice and administrative controls are closely related attempts to change behaviors. They are management-dictated work practices and policies to reduce or prevent exposures to ergonomic risk factors. Work practice and administrative control strategies include:
Although engineering controls are preferred, work practice and administrative controls can be helpful when engineering controls are not technically feasible. However, since work practice and administrative controls focus on eliminating or reducing exposure (not the hazard itself), they require diligent management, training, supervision, and enforcement to be effective. They work only as long as people behave!Common examples of administrative control strategies for reducing the risk of MSDs are as follows:
Check out this short audio clip by Dan Clark of the theSafetyBrief.com. Stretch breaks for employees have big benefits. You lose a little production time, but make bigger gains in productivity. In this podcast, Dan mentions many computer and mobile apps to schedule and time a stretch break.
One of the most controversial questions in the prevention of MSDs is whether the use of personal equipment worn or used by the employee (such as wrist supports, back belts, or vibration attenuation gloves)is effective. Some consider these devices to be personal protective equipment (PPE).
In the field of occupational safety and health, PPE generally provides a barrier between the worker and the hazard source. Respirators, ear plugs, safety goggles, chemical aprons, safety shoes, and hard hats are all examples of PPE. Whether braces, wrist splints, back belts, and similar devices can be regarded as offering personal protection against ergonomic hazards remains open to question.
Although these devices may, in some situations, reduce the duration, frequency, or intensity of exposure, evidence of their effectiveness in injury reduction is inconclusive. In some instances they may decrease one exposure but increase another because the worker has to "fight" the device to perform his or her work. An example is the use of wrist splints while engaged in work that requires wrist bending.
On the basis of a review of the scientific literature completed in 1994, NIOSH concluded that insufficient evidence existed to prove the effectiveness of back belts in preventing back injuries related to manual handling job tasks [NIOSH 1994]. A recent epidemiological study credits mandatory use of back belts in a chain of large retail hardware stores in substantially reducing the rate of low back injuries [Kraus 1996]. Although NIOSH believes this study provides evidence that back belts may be effective in some settings for preventing back injuries, NIOSH still believes that evidence for the effectiveness of back belts is inconclusive. More on backbelts.
Less controversial types of personal equipment are vibration attenuation gloves [NIOSH 1989] and knee pads for carpet layers [Bhattacharya et al. 1985]. But even here, there can be concerns. For example, do the design and fit of the gloves make it harder to grip tools?
There you have it! Almost everything you need to know about ergonomic control strategies, right? Well, not quite, but you do have a good introduction to them. Remember, ergonomics control strategies may not be immediately obvious. If you can't figure out an effective solution, don't forget to take advantage of an outside expert. Participating in the consultation process with an ergonomist is a real win-win for your company and an excellent education for you.
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