Take a deep breath

Various respiratory protective products are available on the market. Precision Safety Appliances (PSA) shares some insights about respirators and how to choose the right one for the job.

Types of respirators

Air-purifying respirators: These are used in environments where sufficient oxygen is present and the specific gas hazard has been identified and quantified. Portable or fixed instruments are able to provide continuous oxygen readings, and are also available with toxic sensors to detect and quantify specific toxic hazards.

Independent air supply: Self-contained breathing apparatus or airline respirators are suitable for environments where the oxygen content is low, or the toxic gas is beyond the protection ability of air purifying respirators, since they provide an independent source of safe air. Despite the independent air source, there is still the possibility of a flammable atmosphere that needs to be considered, which is why the environment should still be tested.

What equipment limitations need to be considered when selecting respiratory protection?

Self-contained breathing apparatus (SCBA): SCBAs provide a readily available supply of independent air; however, they are restrictive in that they will only provide working time relative to the pressure available in the cylinder (typically about 30 to 40 minutes).

Airline respirators: Using a suitable compressor as the source of air provides the benefit of continuous availability of air, while the compressor is running. The connection points are, however, generally fixed around the factory and may not always be situated close enough to where the compressor is required. Portable compressors providing “breathing quality air” are very useful, but costly, and thus often considered more suitable as a rental option.

Escape respiratory protective devices: These are available in either “air-purifying” or “stored pressure” format. The former is often worn by personnel in factories as personal protective equipment where the general possibility of a specific gas hazard, or potential leak, is present. In such instances, the respirator is quickly put on and the worker evacuates the plant. They are not suitable for oxygen-deficient atmospheres.

“Stored pressure” escape devices have compact air cylinders containing sufficient air for escape purposes and provide an independent supply of air, thus making them suitable for oxygen-deficient atmospheres. While they are more cumbersome than air purifying devices, they provide a suitable backup should the airline supply line be interrupted.

Why do you need both gas detection and respiratory protection?

Respiratory protection does not provide the user with a means to detect the presence of flammable vapours, toxic gases, volatile organic compounds or an oxygen-deficient or oxygen-enriched atmosphere. Gas detectors should be considered, even while donning the respiratory protection, since the results provide an indication of the concentrations in the atmosphere.