Personal Air Sampling for Crystalline Silica Exposure
This PowerPoint was presented on April 14, 2016 to the NASA industrial hygiene community as part of a video teleconference on the new silica standard. There is another PowerPoint presented by CPWR staff for the NASA video teleconference. This short PPT covers the traditional methods for collecting and analyzing respirable crystalline silica samples. Traditional cyclonic separators, like the Dorr-Oliver are reviewed, but newer units that allow higher flow rates and, therefore, lower detection limits are also highlighted. CPWR does not endorse particular brands of equipment, but appreciates Ron Roberson of Sensidyne allowing us to post this PowerPoint.
Traditional Sampling Methods for Respirable Crystalline Silica
- NIOSH 7500: Crystalline Silica via XRD
- NIOSH 7601: Crystalline Silica via Visible Spec
- NIOSH 7602: Crystalline Silica via IR
- OSHA ID-142: Crystalline Silica via XRD
- Field methods were similar, but lab method varied
Traditional Cyclones for Respirable Silica Sampling
- Dorr-Oliver 10 mm Nylon Cyclone at 1.7 LPM
- Higgins-Dewell Cyclone at 2.2 LPM
- Aluminum Cyclone at 2.5 LPM
Cyclone Calibration Jar For Dorr-Oliver Cyclone
Particle Size Distribution-US ACGIH
High Flow Rate Cyclones
- GK 2.69 at 4.2 LPM (37mm NIOSH Cassette)
- GK 4.162 RASCAL at 9 LPM (47mm)
- FSP-10 at 11.2 LPM (37mm Euro Cassette)
NIOSH Testing of High Flow Cyclones
- Performance of High Flow Rate Samplers for Respirable Particle Collection; NIOSH; Lee, Kim, Chisolm, Slaven & Harper; Amer Occup Hyg; Vol 54, No. 6, 2010.
- Quartz Measurement in Coal Dust with High-Flow Rate Samplers: Laboratory Study; NIOSH; Lee, Lee, Kim, Chisolm, Kashon & Harper; Amer Occup Hyg; Vol 56, No. 4, 2011.
|Cyclone Model||Part Number||Construction Material||Overall Height (mm)||Approx. Weight (Kg)||Flow rate ACGIH Resp (50% @ 4μm) (US)||Flow rate BMRC Respirable (50% @ 5μm) (Europe)||Flow rate Thoracic (50% @ 10μm)|
|10 mm Dorr-Oliver||800061||Nylon||160||0.08||1.7 LPM|
|BGI-4L, HD style (US version)||811-9924-01||Aluminum||105||0.15||2.2LPM||2.0 LPM||1.0 LPM|
|FSP-2HD style-European Version||811-9930-01||Aluminum||130||0.14||2.2 LPM||2.0 LPM|
|Medium flow rate GK 2.69 for 37 mm cassettes||811-9926||Aluminum||125||0.10||4.2 LPM||1.6 LPM|
|High flow rate RASCAL Cyclone with Plastic Filter Holder||811-9925-01||Aluminum||170||0.26||8.5 to 9.5 LPM|
|FSP-10, High flow rate cyclone||811-9931-01||Aluminum||203||0.26||11.2 LPM||10 LPM|
Gilian 10i High Flow Sampling Pump
- 4 – 10 LPM Flow Rates
- Backpressure Capability up to 50” H2O @ 4 LPM
- Intrinsically Safe Certified
- Built on the Proven-reliable Gilian 5000 Platform
Gilian 12 High Flow Sampling Pump
- Flow Rates from 4 – 12 LPM
- Extreme Backpressure Capability to 67” H2O @ 4LPM
- Designed for high Flow Rate Cyclones
- Ideal for Sampling Trains Creating High Backpressure Across the Entire Sampling Period
Appendix A: Methods of Sample Analysis
- “This appendix specifies the procedures for analyzing air samples for respirable crystalline silica, as well as the quality control procedures that employers must ensure that laboratories use when performing an analysis required under 29 CFR 1926.1153 (d)(2)(v)”.
- References the six methods as acceptable for the laboratory analysis methodology & specifies minimum QA.
- Makes the statement: “Optimizes methods and instruments to obtain a quantitative limit of detection that represents a value no higher than 25 percent of the PEL based on sample air volume”.
Methods Listed in Silica StandardFor Lab Reference
|Method No.||Analysis||LDL (1.7LPM)|
|OSHA ID-142||XRD, Redeposition||12.0 μg/m3 (qtz)|
|NIOSH 7500||XRD, Redeposition||6.12 μg/m3 (8 hr)|
|NIOSH 7602||IR, KBr Pellet||6.12 μg/m3 (8 hr)|
|NIOSH 7603||IR, Redeposition||12.24 μg/m3 (8 hr)|
|MSHA P-2||XRD, Redeposition||24.48 μg/m3 (8 hr)|
|MSHA P-7||IR, Reseposition||24.48 μg/m3 (8 hr)|
Air Sampling Review
- Must have a large enough sample to obtain a maximum limit of detection of 12.5 micrograms per cubic meter (i.e., 25% of 50 micrograms per cubic meter).
- Must use the analysis by XRD or IR, as described in the six listed methods.
- The laboratory must meet minimum specified QA requirements.
Air Sampling Equipment Review
- Always observe the cyclone flow rate specification for meeting the ACGIH size selection curve (50% at 4 microns).
- Always use a constant flow control pump that will keep the flow rate at +/- 5% of set flow.
- A medium flow cyclone can meet the detecting limit in an 8 hour sample and still be comfortable to wear.
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