Selecting Respiratory Protection in the Chemical Sector

Respiratory Protection Dust control regulations and the regulations issued regarding health and safety measures in work with chemical substances always prioritize how dangerous substances can be eliminated or replaced with less hazardous materials. However, when it is impossible to adequately protect human health under any circumstances, personal protective equipment is used as a last resort. Although personal protective equipment is used as a last resort, incorrect selections can actually become situations equivalent to not using any personal protective equipment at all. In a work environment, particularly if we are talking about a work environment where dangerous chemicals are used intensively, such as the chemical sector, we must first ensure that risk analyses have been conducted very thoroughly by the occupational safety department. It is necessary to complete material safety data sheets (MSDS) for the chemicals used in the work environment. Subsequently, environmental and personal exposure measurements must be conducted based on the hazards present in the environment. It is important to emphasize here that these MSDSs should be shared with the firm conducting the measurements and that measurements must be performed based on chemicals that could be generated in the environment. Following dust measurements and chemical gas/vapor measurements, the occupational safety team should determine which personal protective equipment needs to be used. In this article, I will specifically discuss respiratory protective equipment, which is one of the primary risks in the chemical sector.

As respiratory protective equipment, we can generally classify personal protective equipment into 3 categories:

1- Dust/Particle Masks 2- Reusable Masks 3- Powered Air-Purifying Respirators

Dust/particle masks, as their name suggests, are a type of mask used to prevent particles suspended in the air from entering the body through the respiratory tract.

The standard for dust masks is EN 149+A1, and its general name is "Respiratory protective devices - Filtering half masks to protect against particles - Requirements, testing and marking". Within this standard, it is stated that there are 3 different classifications for dust/particle masks and their designation is referred to as FFP1, FFP2, and FFP3. Looking at these classifications, the standard specifies that different sized particle mixtures are sprayed onto a mannequin in the specified apparatus and the nominal protection factors (NPF) for FFP1, FFP2, and FFP3 should be 22%, 8%, and 2% respectively. If we want to simplify this for everyday use, based on the maximum permitted concentration (MAK) values mentioned in dust control regulations, we can say that FFP1 has an NPF value of 4xMAK, FFP2 has 12xMAK, and FFP3 has 50xMAK. Dust/particle masks are generally single-use. However, in some cases, multiple use may also be possible. The most correct way to understand this is through the "NR" and "R" markings on the mask, as specified in the EN 149+A1 standard. The NR marking indicates non-reusable, i.e., single use, while the R marking indicates reusable, i.e., multiple use. Dust pads typically used on half-face and/or full-face masks are also suitable for multiple use.

Whether single-use or multiple-use, the end of life of dust/particle masks is understood when there is an increase in breathing resistance.

However, in this case, if there is no increase in breathing resistance at the end of single use for single-use dust/particle masks, it does not mean they are suitable for multiple use; this point requires particular attention. Reusable masks are generally referred to as gas masks in Turkey. However, they actually refer to half-face masks and full-face masks. The reason for this is that, whether half-face or full-face masks, as long as the filters are replaced and there is no damage on the mask that could prevent its use, they can be washed/disinfected and reused. With half-face and/or full-face masks, not only gas/vapor filters are used. In some cases (such as when a single-use mask does not fit the employee's face, or when the employee prefers to use a half-face mask, etc.) or when a higher level of protection is required, reusable masks can be used with dust/particle pads or filters. Compliance with standards in reusable masks is another important matter. Half-face masks should have EN 140 standard, full-face masks EN 136 standard, activated carbon filters EN 14387+A1 standard, and dust pads EN 143 standard. The correct selection of activated carbon filters is important here. The table below specifies which symbol should be used for which chemical type. The table should be considered when making a selection.

For reusable masks, it is understood that the service life of dust/particle pads has expired when breathing resistance increases, while the service life of activated carbon filters expires when the smell of the chemical reaches the worker. As can be concluded from this, activated carbon filters are suitable for odorous chemicals.

Whether dust/particle filters or reusable masks, the employee must wear the mask correctly on their face and/or the masks must be compatible with the employee's face. To understand these, fit tests, which are mandatory in countries such as the United States and the United Kingdom, must be conducted to verify that the mask is compatible with the employee and worn correctly. Another type of respiratory protective equipment is powered air-purifying respirators or supplied air respirators. Powered air-purifying respirators actually have filters with a much larger surface area, similar to reusable mask derivatives, and draw air not through the human lungs but with the assistance of a motor, as in reusable masks. Air drawn by the motor passes through a large filter and is transferred to the head area via a hose. The general term for these systems is powered respirator system and must comply with EN 12941 standard.

Supplied air systems draw clean air from a compressor with EN 12021 standard, supply it to the head via a small regulator, and must comply with EN 14594 standard. If powered and supplied air respirators are compared with dust/particle and reusable masks;

• Powered and supplied air respirators operate with positive pressure. • While facial hair negatively affects the protection factor with dust/particle masks and reusable masks, facial hair has no effect on the protection factor in powered/supplied air systems. • Since user facial expressions are more clearly visible in powered/supplied air systems, they will be able to communicate more easily. • Generally, the head, eye, and face protection personal protective equipment required when dust/particle or reusable masks are used can be solved with a single integrated system in powered/supplied air systems. • In terms of protection level, depending on the combination, powered and supplied air systems can provide protection at a level higher than dust/particle or reusable masks can achieve. • Particularly in case of clogging of dust/particle filters or battery depletion, they can provide audible, visual, and vibration warnings. Even if powered/supplied air systems with the advantages listed above are used, the priority is still correct risk analysis conducted by the occupational safety team at the workplace, training on using appropriate personal protective equipment for appropriate locations provided to employees, and supervision by the occupational safety team. Mirey Bonfil / 3M Personal Protective Equipment Technical Coordinator