FILTERING THE ENVIRONMENT Contaminants are encountered in different forms, presenting either a particulate or gaseous/vapour hazard or both. Depending on the combination of cartridge/filter and respirator, different levels of protection may be achieved. The higher the protection factor, the greater the reduction in exposure to airborne contaminants for the wearer. Different filters are required to protect against particulates, specific gases or a combination of both.
FIT TESTING The biggest contributor to reduced respiratory protection is poor fit. Checking that a respirator, with a tight fitting facepiece provides an adequate seal to the wearer’s face has long been considered best practice as part of a general Respiratory Protection Program covered under AS/NZS 1715:2009 section 2.6. Respirators with tight fitting facepieces include disposable respirators, half and full-face respirators, including those that form part of a powered or air-fed respirator. Fit testing should be carried out before the respirator is issued, and on all wearers of respirators with tight fitting facepieces where fit testing has previously not been performed. FIT TESTING SHOULD BE REPEATED AT APPROPRIATE TIMES SUCH AS: • If the wearer significantly loses or gains weight, has major dental work or sustain a major facial injury • If a different size or model of Respiratory Protective Equipment (RPE) is specified • At least annually or when specified by the company policy e.g. during a health surveillance check • Fit testing is in addition to performing a self-fit check prior to each use as a determination of suitable fit FIT TESTING METHODS: QUALITATIVE FIT TESTING – Pass or fail assessment conducted to ensure that a respirator with a tight fitting facepiece provides an adequate seal to the Wearer’s face. QUANTITATIVE FIT TESTING – An assessment of adequacy of respirator fit that uses numerical measurements of the amount of leakage into the respirator.
TYPES OF PARTICULATE FILTERS
CLASS COLOUR APPLICATION
P1
White Particulates generated by mechanical processes e.g. grinding, sanding
P2
White Particulates generated by mechanical and thermal processes e.g. welding
All particulates including highly toxic materials. Used when a higher protection factor is required, however only used in combination with a full-face respirator
P3
White
Particulate filters should not be worn when oxygen levels are not guaranteed to be > 19.5%; for capture of gases and vapours; when the airborne particulate contaminant concentrations are very high, and when Government regulations require use of airline or other specific type of respirator for specific applications.
GAS & VAPOUR FILTERS
FILTER COLOUR MAIN FIELD OF APPLICATION AX
Organic Vapours (boiling point < 65°C) Organic Vapours (boiling point > 65°C)
A B E K
Acid Gases
Inorganic Gases
Ammonia Mercury
Hg
G
Organic Compounds with low vapour pressure
Gas and vapour filters must not be used when oxygen level are not guaranteed to be > 19.5%, for capture of particulate e.g. dusts, mists fumes or fibres, when airborne gas and vapour contaminant concentrations are very high, when spraying materials contains isocyanates, where the contaminants present cannot be captured by the gas and vapour filter, when regulations require use of airline or specific type of respirator for certain applications.
Bunzl Safety can provide advice and support on the use of 3M Respirator Fit Check Test Kits.
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