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Safeguard OSH Solutions - Thomson Reuters

Safeguard OSH Solutions - Thomson Reuters

Safeguard Magazine

Last line of defence

The appropriate and efficient use of PPE is not always a straightforward matter, says IAN LAIRD.

The use of personal protective equipment (PPE) is an integral part of occupational health and safety strategies for reduction and control of hazardous exposures in the workplace.

The preference is to control hazards at the source and make the workplace safe, so PPE should only be necessary when it is proven impractical to control the hazards by other means. Personal protection is therefore usually regarded as the last line of defence.

The use of PPE usually implies that the worker is expected to operate in a potentially hazardous environment with the protective device as one of the key means of reducing exposure. It is, therefore, vital that the effectiveness and reliability of the device is ensured.

Unfortunately, personal protection is often seen as an inexpensive solution for controlling occupational hazards. Little consideration is given to the selection of suitable and effective devices, the maintenance of these devices, and the training of people using such equipment.

The most common strategy

There is extensive evidence that PPE is the most commonly utilised control strategy for occupational hazards, and recent evidence finds its use is increasing. Respiratory protective equipment (RPE) and hearing protection devices are two of the most frequently used types of PPE.

Research over a 30-year period indicates that air purifying respirators are one of the most extensively used devices in industry. These devices have the capacity to attenuate or reduce exposure to hazardous airborne contaminants by a factor of 10. This “protection factor” is the ratio of concentrations of contaminant inside and outside the face piece of the respirator.

More sophisticated respirators have protection factors in the hundreds or thousands. In a similar way, the noise reduction rating (NRR) is a simple guide for consumers and professionals to indicate the amount of noise reduction, in decibels, that users might obtain when wearing a particular hearing protector.

Higher numbers were intended to denote greater effectiveness, with values ranging from 0 to 33 dB. Many different studies over the last 25 years have shown that the NRR overestimates the amount of protection that most wearers obtain under normal wearing conditions.

In response to these studies, OSHA, NIOSH, and even the hearing protector manufacturers themselves have recommended that the NRR be routinely reduced by a factor of 50% or more in order to better predict the effective protection provided by the device.

Given these characteristics, the current technology behind PPE provides the potential for the devices to significantly reduce hazardous workplace exposures. In addition, PPE is a relatively inexpensive means of providing immediate and effective protection at the point of exposure.

So why then has the incidence and prevalence of occupational disease in the New Zealand workplace increased, rather than decreased, dramatically over the last 10-20 years?

PPE use and misuse

Although PPE is used extensively, research suggests that much of that use is poorly implemented. As a consequence the outcome is inappropriate or ineffective protection of the user which leads to subsequent continued – or even enhanced – exposure to the hazard.

Estimates range from RPE and hearing protection being worn for only 30 to 60 percent of the time that they should be (required to be) worn. Also, estimates have indicated that if PPE is worn, then only a small proportion of the devices are worn “effectively”, that is with individual protection factors approaching the designed specifications of the equipment.

What, then, are some of the factors behind the non-use and misuse of PPE? The appropriate and efficient use of PPE is a complex phenomenon. It is simply not a matter of casually donning a device.

The major determinants for the use of PPE reported in the literature include risk of exposure and the employees’ knowledge of the consequence of such exposure. The major barriers to employees using PPE include: physical discomfort, lack of time, perception of low risk, and disbelief in its efficacy.

The relative importance of these factors varies with the work environment and sometimes with the specific PPE. In the case of respiratory protective equipment, usage factors are also possibly influenced by the type of equipment.

A number of key themes have been identified. Some of these relate directly to the effectiveness of RPE programmes in persuading employees to wear RPE, others can be related more to its effectiveness once worn. Nevertheless, all seem to be of potential importance in achieving the overall aim of improved workplace protection.

Factors relate to the willingness of the employees to wear RPE in the first place. These include: hazard awareness; risk perception; perceived effectiveness of protection; management attitudes and leadership; and the time and/or hassle involved with donning the device.

Once worn, other factors come into play, mainly relating to comfort and disability issues. These include: resistance to breathing; discomfort (such as pressure or chafing); thermal discomfort; impaired communication; and other interactions or interference with work activities.

Many of the factors likely to adversely affect wearability (eg weight, pressure against face, and size) are to some extent correlated with functional performance.

Although not directly contributing to wearability, inadequate maintenance, cleaning, or replacement programmes can also influence overall effectiveness. Through factors such as increased respiratory resistance or reduced airflow, the acceptability of the PPE can also be indirectly influenced.

The frequency with which it is necessary to wear respirators, the type of respirator, and an individual worker’s experience were also found to influence workers’ behaviour towards the use of respirators (Graveling et al, 2011).

In the case of hearing protection use, studies in the US indicate that there has been an increase in the use of hearing protection. Several factors are reported to influence the wearing of hearing protection, such as health beliefs, perceived risk and probability of risk, along with the comfort of wearing the device. Based on these models, several trials have been conducted to study the effectiveness of interventions to influence the wearing of hearing protection and to decrease exposure.

The evidence found in a recent Cochrane review (El Dib, Mathew & Martins, 2012) shows that tailored interventions improve the mean use of hearing protective devices compared with non-intervention. Individually tailored education was more effective in improving the use of hearing protection devices compared with targeted education programmes which address shared worker characteristics.

Control at source not pursued

A number of studies have indicated that hazardous exposures (to chemicals and noise) in the workplace can usually be readily identified. In addition, some attempts to investigate the potential to control or manage these exposures at source may be undertaken by employers, but usually not pursued, for a variety of reasons.

These include time (to devote to developing and implementing solutions), resources (technical and personnel) and cost (of implementation of effective controls). In addition, studies – primarily in small enterprises – have identified some important features of employer and employee understanding of exposures and controls.

They indicate that knowledge of OHS legislation, standards and hazard management is generally poor; there is a dependency on suppliers for information; inadequate knowledge of health effects; better perception of acute rather than long term health effects; and controls are often decided by custom and practice and not by risk assessment.

What, then, can be done to develop our thinking around control at source?

Control at source strategies

The first “control at source” strategy should be one of elimination. The Prevention through Design (PtD) initiative developed by NIOSH (2010) is a good example of this.

The aim of PtD is to eliminate or reduce the potential exposures created by equipment and machinery used in the community and industry sectors. Through utilising the four functional areas (research, policy, practice, and education) of the PtD process, the approach consists of developing collaborations or partnerships, procedures, resources, implementation plans, design strategies, case studies, and Research to Practice (r2p) initiatives from identification of the problem to implementation.

This would involve developing collaborations with equipment and machinery manufacturers and distributors, government and community agencies, and other groups.

The second “control at source” strategy is one of design and engineering. For the management of hazardous chemicals strategies should include elimination or replacement of hazardous chemicals and processes, more specific engineering modification at source, more specific and direct enclosure of machinery and equipment, extraction and ventilation at source, and regular maintenance of machinery and equipment.

Similarly, for the management of noise sources, strategies should include elimination or replacement of old machinery, more specific engineering modification at source, more specific and direct enclosure of machinery and equipment, use of vibration isolation, regular maintenance of machinery and equipment, implementation of a “buy quiet” purchasing policy, and use of administrative controls.

The Industrial Noise and Vibration Centre in the UK suggest that noise is not a safety issue. Rather, it’s an engineering problem that should be solved by engineering means. In addition, the use of “best or good practice” elements can produce noise control measures that actually improve productivity and reduce costs – in contrast to reliance on conventional enclosures and acoustic guarding.

It seems we need a change in expectations around hazard management. Not only do we need to promote innovative “best” or “good” practice models but we need less reliance on PPE and much more of a risk-based approach. Much better compliance with the duty to reduce exposures by engineering means is expected. This involves less assessment and process and more action. If solutions have been identified – “stop assessing and start controlling”.

Associate Professor IAN LAIRD teaches at the Centre for Ergonomics, Occupational Safety and Health at Massey University’s Palmerston North campus.

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