Dust (Not Otherwise Classified) Management Guideline
GAVIN MOREIRA, Member Services Manager of the CMPA provides an extract on the new Dust (Not Otherwise Classified) Management Guideline.
This Dust (Not Otherwise Classified) Management Guideline together with the CMPA’s Work Safely Reference Manual aims to support members in meeting the requirements of the Victorian Occupational Health and Safety Act 2004 and the Victorian Occupational Health and Safety Regulations 2017.
In doing so, the CMPA endeavours to:
Provide members with appropriate management practices required to minimise potential health and safety risks associated with dust arising from construction materials industry operations;
Scope of Guideline
This Dust (Not Otherwise Classified) Management Guideline is specific to dust arising from the workplace and its potential impact to workplace health and safety within the workplace boundaries.
The guideline does not include guidance in controlling the risks associated with respirable dusts inclusive of Respirable Crystalline Silica Dust (RCSD) nor Environmental Dust (dust that is carried across the site boundaries) and its potential impact on human health and the environment.
For information on these dust types, please refer to:
• CMPA RCSD Management Guideline, Issue 2 March 2022; or
• CMPA Environmental Dust Management Guideline (to be developed 2023)
• CMPA Environmental RCSD Management Guideline (to be developed 2023)
The scope of this Dust Management Guideline is inclusive of the following matters:
• Legislation;
• Dust Definition, Measurement, Weight and Classification;
• Dust Generation and Carriage
• Dust Impacts
• Mineral Assemblage of Rock;
• Workplace Exposure Standards;
• Hazardous Substances and Safety Data Sheets (SDS);
• Workplace Exposure Standards;
• Dust Monitoring and Measurement; and
• Dust Control.
Workplace Exposure Standards
SWA set exposure standards for hazardous substances which are then adopted by the state or territory Work, Health and Safety regulatory authorities such as WorkSafe Victoria.
Exposure standards are based on the airborne concentrations of individual substances that, according to current knowledge, should neither impair the health of, nor cause undue discomfort to, nearly all workers. They do not represent a fine dividing line between a healthy and unhealthy work environment.
The following dusts used in the construction materials industry have an exposure standard assigned to them by SWA based upon the Respirable Dust Fraction:
• Quartz
• Fumed Silica
• Asbestos (imported material)
These respirable dust particles are known as classified dusts
by SWA as they have an exposure standard assigned to them.
Exposure Standards for Dusts not otherwise Classified
Not all dusts have an exposure standard assigned by SWA.
However, it should not be assumed these dusts do not present a hazard to health (refer to Health Surveillance p.12).
Where no specific exposure standard has been assigned and the substance is both of inherently low toxicity and free from toxic impurities, exposure to dust should be maintained below 10 mg/m3 over an 8-hour Time Weighted Average.
Action Levels/ Trigger Values:
The objective on an Action Level/Trigger Value is to trigger actions to control exposure ensuring all worker exposures stay well below an exposure standard.
The Australian Institute of Occupational Hygienists (AIOH) recommends trigger values for these other dusts as 5 mg/m3.
Time Weighted Average (TWA):
TWA is the average airborne concentration of a particular substance when calculated over a normal eight-hour workday, for a five-day working week, i.e., 40 hour week.
To ensure the exposure standards and action levels are representative of the time worked e.g., many formulas can be used to establish the TWA.
In simple terms to adjust the exposure standard to a 50-hour week the following calculation is used.
10 mg/m3 X (40 hours divided by 50 hours) = 8 mg/m3.
Exposure standards are measured at the persons breathing zone.
Breathing zone means a hemisphere of 300 mm radius extending in front of a person’s face and measured from the midpoint of an imaginary line joining the ears.
You must be logged in to post a comment Login