With the presence of airborne hazards in the work environment, it is important to choose a respirator that is comfortable and convenient to wear but also approved/certified for protection against the majority of airborne workplace hazards.
So what are these airborne hazards?
Airborne hazards include dust, fogs, fumes, mists, gases, smoke, sprays or common vapours.
The best form of protection is to eliminate or prevent the hazard by altering workplace practices or accepted engineering control measures. When controls are not feasible, appropriate respirators must be used.
Is a disposable mask all that is needed to protect against harmful airborne material?
No. There are six types of airborne hazards - Dust, mist, fume, vapour, gas and oxygen deficiency/enrichment.
Respiratory gear is designed, manufactured, tested and Certified for use against a number of different hazards and should be selected for a specific purpose. Charts are available to choose the appropriate protection. Check the charts and the label/type of each respirator.
P1 rated respirators protect against mechanically generated particles.
P2 rated respirators protect against mechanically and some thermally generated particles. Respirators fitted with an Active Carbon Filter protect against nuisance-level organic vapours.
P3 rated respirators protect against highly toxic or irritant particles.
How do I recognise the six forms of airborne hazards?
• Dust: Formed by the breaking down of solid materials, normally when materials are altered. For example, sanding, cutting, grinding and brushing. In general, the smaller the dust particle, the greater the hazard that it presents. Fibres from materials should also be treated as dusts.
• Mist: Formed by the processes that involve atomisation (such as spraying, cleaning and cutting/grinding using coolants) and consists of tiny liquid droplets rather like steam in a bathroom.
• Fumes: Formed by the vapourisation of a solid material by the application of intense heat. Extremely fine particulates are formed as the fumes cool and condenses. Many processes form fumes, such as smelting, pouring metals and many welding applications.
• Vapour: A gaseous state formed by evaporation from substances that are normally solid or liquid at room temperature. Generally released at room temperature (petrol, methylated spirits), many industrial processes used in degreasing vapourise particularly quickly once heated.
• Gas: An air like substance at room temperature. Gases can travel far, very quickly.
• Oxygen Deficiency/Enrichment: When an atmosphere is likely to contain less than 18% oxygen (or where conditions may exist in the future for this to happen); and in certain circumstances where the risk may be oxygen enrichment, which can lead to explosion and severe impairment of operatives.
Note: Monitoring devices should always be used to check oxygen levels of an unknown environment. Conventional dust masks are not suitable for oxygen deficient situations.
What is the Standard for respirators and how are they tested?
AS/NZS1716:2003 is the Standard that dust masks must comply with in Australia and New Zealand. Each device must be tested to show that it provides effective respiratory protection against certain hazards. The respiratory device should be issued as part of a full respiratory protection program that covers: Hazard Control, Selection of PPE, Fit Testing, Maintenance and Storage Procedures.
Resistance to Flame Testing
This is where the respirator is assessed for its resistance to heat, for use in hot work environments.
Inward Leakage of Assembled Respirators
Quantitative sodium chloride test - A panel of people assess the performance of the respirator against sodium chloride (a gas which has much smaller particles than those found in the workplace). The test is for fit and does not indicate the performance of the respirator.
Breathing Simulator Test
This is where the respirator is tested on a breathing machine which simulates natural breathing in one of a number of environmental and test conditions such as carbon monoxide, temperature rises, carbon dioxide accumulation, resistance to breathing, positive pressure and exhaled air humidity.
Exhalation Valve Leakage Test
This is where the respirator is checked for potential leakages with a leakage meter apparatus.
Breathing Resistance Test
Breathing resistance is measured under continuous flow conditions at specified flow rates at a temperature of 23 +/- 3°C.
Simulated Rough Usage Test
This tests the respirators under conditions for rough usage and handling such as vibration and impact from falls.
Particulate Filters -Test for Filtering Efficiency
A test for initial filter penetration using an aerosol of sodium chloride.
Simulated Works Test
This test is designed to assess the suitability of self rescue and supply air respirators for a variety of work situations.
Cylinder Valve Requirements
Valves are assessed for construction, materials, pressure rating, valve stem thread, valve outlet connection and manufacturer markings.
Source: ProChoice Safety Gear found on Page 117 of the Pro-Pac Packaging Product Catalogue 2018/19.