Understanding Industrial Dust Types and Sampling Equipment

Industrial Dust Definitions and Sampling Methods

Dust Characteristics

Dust: Solid particles generated by mechanical action such as crushing, handling, grinding, rapid impact, or detonation of organic materials like rock, ore, coal, wood, or plastic. These particles do not agglutinate spontaneously, do not spread easily, and remain suspended in the air for periods dependent on air speed.

Dust Classifications

• Nuisance Dust: Generally considered safe and not recognized as a direct cause of serious pathology, though general non-permissible limits apply.
• Toxic Dust: Dust that can be dangerous to the respiratory system, either by passing from the respiratory tract into the bloodstream or by directly acting on mucous membranes.
• Total Dust: Particles with sizes less than 100 microns.
• Respirable Dust: Includes particles passing through a separation system that corresponds to a theoretical separation by sedimentation, separating 50% of particles with an aerodynamic diameter of 5 microns.
• Unclassified Dust: Dust free of asbestos and containing less than 1% free crystalline silica. The allowable limit value is established at 8 mg, as defined in DS 594.

Air Sampling Equipment Components

Sampling Devices

Personal Sampling Pump: A device designed to drive airflow with controlled ability and maintain less than 5% variability.

Filter Sampling: Typically involves a polyvinyl chloride membrane, 37 mm in diameter, with a 5-micron pore size.

Porta Filter (Filter Holder): A set of three pieces made of polyethylene or other material compatible with the filter and sampling equipment, contained within a cellulose support. The air inlet is on the smooth side, and the outlet is on the lattice face.

Air Line: A plastic or rubber hose connecting the personal sampling pump with the filter holder. It is also referred to as the air line carrier generated between the hoses and the filter.

Flowmeter: Used for calibrating the sampling pump, capable of measuring flow with an accuracy of 5% and a confidence level equal to or greater than 95%.

Filter Holder Plugs: Used to seal the filter cartridge holder and prevent contamination of the filter.

Separation Technology

Cyclone Separator

A device used to separate the respirable fraction from total dust. An example is the 10mm nylon cyclone, which has a 50% cut diameter for particles of 4 microns at a flow rate of 1.7 liters per minute.