Procedures for selecting respirators

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Step1: Identify the hazards and its extent

  • Assess the work environment by determining the nature and extent of the hazard, work rate, area to be covered, existing space and ventilation, mobility, work requirements and conditions.
  • Identify the limitations and characteristics of the available respirators.
  • Follow the guidelines or requirements if a specific standard exists for the hazard (e.g. lead, asbestos).

Step 2: Choose respirators

There are many kinds of respirators available. Choose the respirator that is certified/ approved for the function. Respirator should only be used as last resort!

Basically, respirators can be categorized into two types: Air-Purifying Respirators and Atmosphere-Supplying Respirators.

​Air-PurifyingRespirators

​Atmosphere-SupplyingRespirators

  • These respirators remove air contaminants through the respirator canister or cartridge. They range from simple disposable masks to quarter-, half- and full-face respirators to sophisticated positive-pressure, blower-operated units.
  • Air-purifying respirators must not be used in an oxygen-deficient atmosphere or under conditions that are immediately dangerous to life or health.
    • Particulate removing respirators, which filter out dusts, fibres, fumes and mists. These respirators may be single-use disposable respirators or respirators with replaceable filters.
    • Gas and vapour-removing respirators, which remove specific individual contaminants or a combination of contaminants.
    • Combination particulate/gas- and vapour-removing respirators, which combine the respirator characteristics of both kinds of air-purifying respirators.

 

The following provides information of filters that meet reputable standards. It only applies to non-powered, air-purifying particulate-filter respirators.

 

NIOSH Certificate (42CRF84)

Class of filters Efficiency  Types of contaminant

N-Series: N100/N99/N95 99.7/99/95 Solid and water based particulates (Not resistant to oil)

R-Series: R100/R99/R95 99.7/99/95 Any particulates (Resistant to oil)

P- Series: P100/P99/P95 99.7/99/95 Any particulates (Oil proof)

 

Powered Air-Purifying Respirators

A blower is used to force the ambient atmosphere through the air purifying elements to the inlet covering.

  • Provide breathable air independent of the environment.
  • To be used when the contaminant has insufficient odour, taste or irritating warning properties, or when the contaminant is of such a high concentration or toxicity that an air-purifying respirator is inadequate.
  • They include supplied-air respirators (SAR) and self-contained breathing apparatus (SCBA).
  • SCBA provides respiratory protection for relatively short periods.
  • Positive pressure supplied air respirators can be used in highly contaminated areas for a longer period. It also causes less discomfort than air-purifying respirators because the user needs not overcome filter resistance in order to inhale.

 

Other respirators

  • Negative Pressure Respirators: the air pressure inside the respiratory inlet covering is negative with respect to ambient air during inhalation.
  • Demand Type: this type of respirator supplies air to the user on demand (inhalation) which creates a negative pressure within the facepiece.
  • Positive Pressure Respirators: the air pressure inside the respiratory inlet covering normally is positive with respect to ambient air pressure. This continuous positive pressure within the facepiece prevents leakage into the facepiece.
  • Continuous Flow: this type of respirator maintains a continuous flow of air through the facepiece and prevents leakage into the facepiece.

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Air-Purifying Respirators

  • These respirators remove air contaminants through the respirator canister or cartridge. They range from simple disposable masks to quarter-, half- and full-face respirators to sophisticated positive-pressure, blower-operated units.
  • Air-purifying respirators must not be used in an oxygen-deficient atmosphere or under conditions that are immediately dangerous to life or health.
    • Particulate removing respirators, which filter out dusts, fibres, fumes and mists. These respirators may be single-use disposable respirators or respirators with replaceable filters.
    • Gas and vapour-removing respirators, which remove specific individual contaminants or a combination of contaminants.
    • Combination particulate/gas- and vapour-removing respirators, which combine the respirator characteristics of both kinds of air-purifying respirators.

 

The following provides information of filters that meet reputable standards. It only applies to non-powered, air-purifying particulate-filter respirators.

 

NIOSH Certificate (42CRF84)

Class of filters Efficiency  Types of contaminant

N-Series: N100/N99/N95 99.7/99/95 Solid and water based particulates (Not resistant to oil)

R-Series: R100/R99/R95 99.7/99/95 Any particulates (Resistant to oil)

P- Series: P100/P99/P95 99.7/99/95 Any particulates (Oil proof)

 

Powered Air-Purifying Respirators

A blower is used to force the ambient atmosphere through the air purifying elements to the inlet covering.

Atmosphere-Supplying Respirators

  • Provide breathable air independent of the environment.
  • To be used when the contaminant has insufficient odour, taste or irritating warning properties, or when the contaminant is of such a high concentration or toxicity that an air-purifying respirator is inadequate.
  • They include supplied-air respirators (SAR) and self-contained breathing apparatus (SCBA).
  • SCBA provides respiratory protection for relatively short periods.
  • Positive pressure supplied air respirators can be used in highly contaminated areas for a longer period. It also causes less discomfort than air-purifying respirators because the user needs not overcome filter resistance in order to inhale.

 

Other respirators

  • Negative Pressure Respirators: the air pressure inside the respiratory inlet covering is negative with respect to ambient air during inhalation.
  • Demand Type: this type of respirator supplies air to the user on demand (inhalation) which creates a negative pressure within the facepiece.
  • Positive Pressure Respirators: the air pressure inside the respiratory inlet covering normally is positive with respect to ambient air pressure. This continuous positive pressure within the facepiece prevents leakage into the facepiece.
  • Continuous Flow: this type of respirator maintains a continuous flow of air through the facepiece and prevents leakage into the facepiece.