Translation:Reducing the harmful effects of polluted air at workplaces using respiratory PPE

by Chirkin AV

According to the Ministry of Labor (RF) more than 30% of employees are working in hazardous and / or dangerous conditions, and that number continues to grow. Occupational diseases of the respiratory system are among the most common. It makes extensive use of the latter, and sometimes the only means of preserving the health of workers - personal protective equipment. But the use of RPD not always give the desired result. The Reasons:

1. The use of a completely ineffective RPD because of gross errors in the initial choice of the type of respirator;
2. Low quality obsolete respirators;
3. No individual selection masks, fit tests and training of workers;
4. Insufficient timely replacement of gas cartridges and canisters;
5. Incorrect measurement of the concentration of air pollution.

The choice is completely ineffective respirators

Two ways of penetration of harmful substances under the mask: through the gaps and through the filters

There are different designs of respirators. Due to their structural differences, they have different protective efficacy. Therefore, the use of high-quality, serviceability and certified (approved) respirators in such workplace conditions to which it (by its design itself) is not designed, can not reliably protect workers.

Any respirator degree of protection depends on the leakage of unfiltered air through the gaps between the mask and the face, and (in most common filtering respirators) on the efficiency of the filters. Therefore, after selecting the proper filters, respirator protection level is determined by the degree of leakage gaps, which are formed due to careless donning the mask; its slipping during run-time execution of different movements and / or snagging of objects. The shape, size and location of these gaps are not constant. They are different for different employees, and they are different from one (same) person at different times. As a result, during the use of a respirator on real workplace, the protection level of the respirator becomes a random variable depending on various factors.

In RF, the employer is obliged to use only certified (approved) PPE (including respiratory PPE). Those employers who use PPE, mistakenly believe that the certification ensures the effectiveness of respiratory protective equipment used. But respirator certification test participants, in principle, can not simulate all the enormous variety of movements that make millions of workers, and the limited number of such test participants can not accurately simulate all the different worker’s faces (shape and sizes). In addition, in the laboratory, participants wear respirators’ masks more slowly and carefully. Therefore laboratory efficiency RPD (during the certification) is significantly different from the protective properties in actual use in the workplace. This real efficiency was measured in the developed countries tenfold. These measurements have shown that in actual use gaps formed more frequently; they (on average) larger, and the level of respirator’s protection much lower.

Measurement of the protection coefficient over time. Source: The Annual of Occupational Hygiene, vol. 49(3) 245-257 (2005)

For this reason, there are two types of requirements for reliable respiratory protection of workers using respirators in the US and the EU: a) for the manufacturer of respirators (RPD quality requirements are executed on certification, including requirements for protective properties), and b) for the employer (the requirements for proper selection and proper use of respiratory protective equipment, including limitations on the use of respirators all designs). The table shows the protection coefficients (the ratio of the concentration outside the mask to the in-mask - in inhaled air) for respirators most common designs, resulting from the certification in accordance with the requirements of the relevant RF standards - PF(C); and PF used in the workplace to limiting the allowable safe use of the same respirator while working - PF (W). When selecting respirators for use in certain workplace conditions, the numerical value of its PF (W) should not be lower than the rate of air pollution (the sum of ratios of the concentrations of harmful substances to their PEL). In the last column of the table one can see the rate of excess PF (C) with respect to PF (W).

Protection Factors obtained during certification PF (C) and Assigned PF, which limit the scope of permissible use of respirators PF (P) [ 4,5,7,9,10 ]

Country	Respirator type	PF (C)	PF (W)	PF (C) / PF(W)
USA	Full Facepiece mask	> ~250000A	50	> 50000
USA	Elastomeric half-mask respirators with canisters or carttidges	> ~25000A	10	> 2500
USA	Filtering half-mask respirator class “100”	> 100C	10	> 10
UK	Full Facepiece mask	> 2000	40	> 50
UK	Elastomeric half-mask respirators	> 50B	20	> 2,5
UK	Filtering half-mask respirator FFP3	> 50B	20	> 2,5
RF	Full Facepiece mask	> 2000	Н	—
RF	Elastomeric half-mask respirators	> 50B	Н	—
RF	Filtering half-mask respirator FFP3	> 50B	Н	—

A — PF (C) calculated as the ratio of the concentration of isoamyl acetate in the test chamber to the threshold of perception of its odor [8].

B — for 8 out of 10 certification test participants [ 4,5 ].

C — with a probability of 90% [10].

High requirements for PF(С) respirators contained in the certification standards, and performed in their manufacture and certification, warn hit in the sale of products of poor quality. As can be seen from the table, in the US and the EU to consider differences protective properties of RPE in the laboratory and in the workplace, showing for the certification of more stringent requirements (2.5, 10 and 5000 times). Therefore, the values PF (W) set on the basis of the results obtained are not in the laboratory but in actual workplace conditions during dozens studies respirators of different designs.

The table has no values PF (W) for the RF. The reason is that at the first attempt to entry into the WTO, when RF switched to a system of certification of respirators, similar to the European, requirements for the employer (regulating the right choice and organization of the use of RPE) is not developed, and they do not exist today. But that does not stop their production, certification, marketing and use.

The decrease of the assigned protection factors (APF) after the measurements of the respirators' effectiveness in the workplace

Under the new state standards governing the certification of respirators, and in accordance with the Technical Regulations of the Customs Union "On the safety of PPE", the manufacturer must indicate the application limits of their products - but they have not been established in the RF. This insoluble problem has not stopped resourceful manufacturers RPD: Earlier, in the USSR standards (ГОСТ) contain requirements to respirators, and (simultaneously) in every one of them indicates the limits of permissible applications [1-3]. Following a long tradition, manufacturers moved laboratory values of protection factor ( certification – PF(C) ) in passports, manuals, packaging and product catalog, although these values are not intended for such use. As a result, the efficiency of RPD (in RF) has increased dramatically - up to 50 PELs for half-masks and up to 2000 PELs for full face masks.

But in the new RF standards had no clear and unambiguous instructions limiting the scope (they are not exist at all) – and some of the manufacturers have gone much further. Kimrsky factory “improve” its half-masks protection level to 200 PEL, and (ОАО АРТИ) increased the efficiency of its elastomeric half-mask to > 5000 PEL. The respirator manufacturers from the US and the EU (that started work on the market in RF), began to point to the instruction manuals of respirators excessive rates of protection too. In some cases, the same page indicated different protection factors in different languages. The same path chosen by many authors of books and publications on RPE, a review of which is made in [6]. Authors usually recommend limiting the scope of respirators different designs, based on current standards of developed countries in the laboratory certification.

Maximum Use Concentration of Soviet and RF negative pressure particulate half-mask respirators (published expert's recommendations)

In the US and the EU respirator selection for the known conditions of work should be conducted by trained specialists on the basis of legal requirements and recommendations of the textbooks, which comply with the legislation. And in RF, employers are guided "Standard rules of free issue of special clothing, special shoes and other personal protective equipment ...". But such documents do not distinguish between gas masks and anti-aerosol RPD, considering them along with boots and a quilted jacket. This leads to errors as to evaluate the protective properties of respirators employer must use the values provided by the manufacturer - and they are usually overpriced. More effective respirators often (but not always) are more expensive. So, there are a good opportunity for cost savings (and reduces the level of protection). If we consider that in the RF the majority of occupational diseases are not detected and recorded, it is clear that the choice is quite inefficient respirator does not bear any risk, not only for the manufacturer and seller overestimates efficiency, but also for the employer.

As mentioned, the efficiency of the respirator is a random variable. Measurements in the workplace showed that the average rates of protection of one employee (using the same respirator) may differ a hundred times on different days; and the average rates of protection of different employees (using exactly the same respirators) are very different. So, it is difficult to identify the causes of breathing polluted air workers, and prevents reasonable to require the issuance of more reliable respirators. The reason is that in some cases the proportion of workers using respirators insufficiently effective, such respirators provide protection yet. But such cases do not reduce the risk of occupational diseases in the bulk of the workers. The choice is certainly not enough effective respirators (half-mask) for use in environments in which they can not provide adequate protection because of its design, is the cause of damage to the health of workers for decades in RF.

The use of outdated respirators

In the RF continues the production and use of outdated respirators, some of which developed more than half a century ago, that provides a low level of protection. For example, after installing an impermeable plastic film instead of a filter in an elastomeric half-mask (respirator Ф-62Ш), this half-mask (with knitted fabric on the skirt) can be put on and breathe - the air passes through the gaps between the mask and face. But this "remedy" is used to protect miners from dust at concentrations hundreds of PEL! The same half-mask (ПР7) used in other RF, Ukrainian and Kazakh half-mask respirators (РПГ-67 et al.).

Respirator Fit Test

The use of masks that do not meet people in shape and size

When the face mask and the mismatch (shape and / or size), the probability of occurrence of gaps and reduce the effectiveness of the respirator increases. Therefore, in developed countries, legislation [7] requires the employer to pick up the mask to face individually and validate the choice by using the instrument (because a convenient mask may in some areas adjacent to the face with gaps). To check it, the employer may, for example, spraying a solution of sweet / bitter substances near the face of the worker, who has put on a respirator. If an employee does not feel the taste (when breathing through the mouth) - it means the mask sits tightly enough on the face. The equipment - inexpensive sprayer with a rubber bulb, compressible manually.

To preserve the health of employees need to respirators used in a timely and correct. However, in RF there are no specific requirements for the employer - how to train workers, to teach them what they need to know and do.

Belated replacement canisters and cartridges

Timely replasement of respirators' gas cartridges

For the timely replacement of gas canisters and cartridges, manufacturers and authors of relevant literature (in Russia and in the USSR) recommend the use of harmful gas odor in the mask. But there is a harmful substance, odorless with dangerous concentrations; different people have different sensitivity to odors; in individual sensitivity can be reduced due to the disease, due to the fact that the employee is still attention to work and so on. If the filter is saturated and begins to pass harmful gases, their concentration in the inhaled air increases gradually. In some cases, this leads to "addiction", and the employee does not respond to high levels of concentration that are dangerous to health.

So now the US is completely banned the use of odor under the mask as a criterion for canister or cartridges replacement. The employer is obliged to schedule takes into account the life and conditions of use of a respirator), or they should use the indicators of end of life (End of Service LifeIndicator — ESLI).

Insufficiently accurate measurement of air pollution

Modern personal sampler

For right choice of respirator you need to know the degree of contamination of air. Usually it is not constant, but depends on the time and place. The use of personal sampling pumps and passive diffusion samplers showed that the concentration of pollutants in the air around the face (in the breathing zone), from which should protect the respirator, generally higher than the concentration of indoor air pollution - often dozens of times. Therefore, in the United States to determine air pollution tend to use personal samplers [11]. And in RF officially approved methods require measuring polluted air of the working area. But if one used the results of these measurements in evaluating workplaces (that can give low results), it leads to non-use of respiratory protective equipment (at a concentration of less than PEL) and the use of respirators that is not enough reliable

Conclusions - Inadmissibility reduce hazard class (workplace), while ensuring workers approved RPD

Summarizing, we can say that since the effectiveness of respirator depends on the timeliness of its use, and other factors - is obviously unreliable means of protection, as evidenced by the results of numerous objective measurements carried out in developed countries. Therefore it is necessary - on the one hand - to focus more on automation and mechanization of work in hazardous conditions, ventilation and other means of reducing the pollution of air - as in the US (in underground coal mines in the RF concentration of pollutants in the air reaches tens and hundreds of PEL, and the use of effective ventilation in the United States allows the concentration of dust in the breathing zone below the PEL in most cases [12]), as well as to develop appropriate regulations governing the selection and organization of the use of respirators. On the other hand, you can not use the issue of RPD as a basis for reducing the hazard class working conditions of people working in the polluted atmosphere, since there is no reason to believe that the supply of workers RPD - as it happens in RF now - allows you to securely save their health. Following the development of relevant regulations will need to be differentiated employer contributions to the Social Insurance Fund, depending on how well it fulfills the requirements for the selection and organization of the use of RPE.

The use of respirators

Country	Respirators are used	Respirators provide	The use of respirators permitted
USA	In accordance with the requirements (to the employer) of national law. This ensures the correct choice and use of RPE	They provide reliable protection of the vast majority of workers in most cases	Only in cases where the employer seems that the reduction of pollution in the air to less than 1 PEL - it is impossible or difficult to implement
RF	The state does not regulate the selection and organization of the use of RPE by employer	Because of these reasons - reliable protection of workers does not provide	When the concentration of air pollution (airborne) exceeding the 1 PEL

References

1. ГОСТ 17269-71 Респираторы фильтрующие газопылезащитные РУ-60 м и РУ-60му.
2. ГОСТ 12.4.004-74 Респираторы фильтрующие противогазовые РПГ-67. Технические условия
3. ГОСТ 12.4.028-76 ССБТ. Респираторы ШБ-1 Лепесток. Технические условия
4. ГОСТ Р 12.4.190-99 Полумаски и четвертьмаски из изолирующих материалов. Общие технические условия
5. ГОСТ Р 12.4.191-99 Средства индивидуальной защиты органов дыхания. Полумаски фильтрующие для защиты от аэрозолей.
6. Кириллов В. Ф. О средствах индивидуальной защиты от пыли. Медицина труда и промышленная экология № 8 2011.
7. 29 CFR 1910.134 Respiratory Protection
8. 3M Respirator Selection Guide 2008.
9. US Standard 42 Code of Federal Register Part 84 Respiratory Protective Devices Есть перевод
10. Health and Safety Executive. Respiratory protective equipment at work. A practical guide
11. Lavoue J., M.S. Friesen and I. Burstin. Workplace Measurements by the Occupational Safety and Health Administration since 1979: Descriptive Analysis and Potential Uses for Exposure Assessment The Annual of Occupational Hygiene (2013) Vol. 57, No. 1, pp. 77-97.
12. Jay Colinet, James Rider et all. Best Practices for Dust Control in Coal Mining NIOSH 2010.