Respirable Dust Sampling Mean?
Respirable dust sampling is the process of measuring the concentration of airborne contaminants in a given space. The aim is to quantify the risk of inhaling air from the atmosphere and determining whether respiratory protection is needed to breathe safely.
Air sampling is very common in industrial settings, where many workers are routinely exposed to a high concentration of harmful particulate matter.
Safeopedia Explains Respirable Dust Sampling
In sufficient concentrations, dust in the air can be a significant health and safety hazard. It can, in particular, affect the sinuses and respiratory system. OSHA standard 1910.134(a) requires employers to provide respirators to workers who may be exposed to high levels of respirable dust while on the job.
Dust Sampling Methods
There are several sampling methods used to find the presence of dust and other particulate matter in the air:
- Direct measuring methods, including hand-pump detector tubes and diffusive detector tubes. These methods provide rapid results, allowing employers to quickly assess risk levels and immediately initiate control measures.
- Instrumental methods used to measure the concentration of chemical impurities in the air and assess the atmosphere of a space before entering it, such as using multi-gas detectors to detect the presence of chemical compounds.
- Air sampling methods, including gas bags, charcoal-absorbent tubes, cyclone samplers, and cowl samplers. Charcoal-absorbent tubes are used for sampling organic vapor, cyclone samplers are used for sampling respirable dust, and cowl samplers are used for fiber sampling.
Filters Used in Dust Sampling
Filter selection is an important factor to consider in dust sampling. There are two types of dust filters to choose from: pre-weighed and matched weight.
Pre-Weighed Filter Analysis
This type of filter is weighed at the beginning of the analysis. It is then placed in cassettes, color-coded, and given a unique identification number. Once the sampling is completed, the entire cassette assembly is weighed. The difference in the weight before and after the sampling indicates the amount of dust trapped by the filter – and, therefore, present in the air.
Matched Weight Filter Analysis
This type of filter does not require initial weighing. Instead, it uses a cassette with two filters of equal weight. Dust is collected on the top filter, while the bottom filter is a blank that essentially acts as a pre-weight. Both filters are then weighed and the difference between them is the reported number.