Basics of Respirators

Definitions

• Canister or Cartridge: a container with a filter, sorbent, or catalyst, or combination of these items, which removes specific contaminants from the air passed through the container.
• Employee exposure: exposure to a concentration of an airborne contaminant that would occur if an employee were not using respiratory protection.
• Fit Factor: a quantitative estimate of the fit of a respirator to a specific individual.
• Fit Test: the use of a protocol to qualitatively or quantitatively evaluate the fit of a respirator on an individual.
• Fogs: are vapors which have condensed into tiny airborne particles or droplets.
• Gases: materials that become airborne at room temperature.
• Mists and Sprays: very small droplets of liquid materials suspended in the air.
• Oxygen Deficient Atmosphere: an atmosphere with an oxygen content below 19.5% by volume.
• Service Life: the period of time that a respirator, filter or sorbent, or other respiratory equipment provides adequate protection to the wearer.
• Vapors: substances created when a solid or liquid material evaporates.

Factors in Choosing a Respirator

• Length of exposure - How long will you be breathing in the dust particles? e.g. 2 or 8 hours
• Type and toxicity of contaminants - What kinds of contaminants or toxins are in the air?
• Concentration level of contaminants - How much of the contaminants or toxins are in the air?
• Size of particles - How deep in your respiratory system can the dust particles go and how long will the dust remain in the air? 
• Activity level and breathing rate - What will your activity level be? It's important to know that breathing through a respirator is harder than breathing in open air and to choose one that is conducive to the job.
• Age and overall health - How old are you and do you have any health conditions?

particulate dust types

Respirable Dust: Particles < than 10 μm (microns) and are small enough to penetrate the nose and upper respiratory system and deep into the lungs or gas exchange region. Generally, beyond the body’s natural clearance mechanisms of cilia and mucous and are more likely to be retained in the lungs. This type of dust is more dangerous to our longtime health because it accumulates in our respiratory system. 

Inhalable Dust: Dust which enters the body, but is trapped in the nose, throat and upper respiratory tract

Types of Respirators

• Air Purifying Respirators (APR): a respirator with an air purifying filter, cartridge, or cannister that removes specific air contaminants by passing ambient air through the air-purifying element. Cannot and must not be used in oxygen deficient atmospheres!

Types of APRs:

• Air Purifying Disposable Particulate Respirator
• i.e. Dust Mask
• Air Purifying Half-Mask Respirator (only covers mouth and nose )
• Air Purifying Full-Face Mask Respirator (encapsulates the entire face )
• Gas Masks
• Powered Air Purifying Respirator (PAPR)
• uses a blower to force the ambient air through air-purifying elements to the inlet covering.
• Atmosphere Supplying Respirator (ASR): supplies the respirator user with breathing air from a source independent of the ambient atmosphere.  

Two types of ASRs:

• Supplied Air Respirator (SAR): an atmosphere supplying respirator for which the source of breathing air is not designed to be carried by the user.
• Supplied Airline Respirator
• Air Cart and Airline
• Self Contained Breathing Apparatus (SCBA): an atmosphere supplying respirator for which the breathing air source is designed to be carried by the user.
• SCBA
• Escape-Only Respirator

NIOSH N95 Respirators :

(N= Not oil Resistant R=Resistant to oil   P=Oil Proof)

N95 respirators are common, the N stands for "not oil resistant" and the 95 means it removes 95% of all particles that are at least 0.3 microns in diameter.

N95 / R95 / P95 masks filter out 95% of dust particles 

N99 / R99 / P99 masks filter out 99% of dust particles

N100 / R100 / P100 masks filter out 99.7% of dust particles