Saulius Trakumas, Eddie SalterSKC Inc., Eighty Four, United States

SKC Ltd., Blandford Forum, United Kingdom

HIGH-FLOW PERSONAL SAMPLER TO MONITOR EXPOSURE TO

RESPIRABLE CRYSTALLINE SILICA AT NEW LOWER TLV

Crystalline Silica

Crystalline silica is a basic component of soil, sand, granite,

and many other minerals.

Hazards of Crystalline Silica

Exposure to silica is a serious threat to million of workers, including workers in high risk jobs such as abrasive blasting,

foundry work, stonecutting, rock drilling, quarry work, and tunneling.

Hazards of Crystalline Silica

Occupational exposure to respirable crystalline silica is associated with the development of silicosis, lung cancer,

and other pulmonary diseases.

Hazards of Crystalline Silica

Exposures to silica may also be related to the development of

autoimmune disorders and other adverse health effects.

Recent studies have demonstrated that lifetime exposure to respirable

crystalline silica at 0.05 mg/m3 is not low enough to eliminate the risk of developing chronic lung diseases.

Permissible Exposure Limits

Permissible Exposure Limits

The American Conference of Governmental Industrial Hygienists

has lowered the 8-hour time-weighted average threshold limit

value to 0.025 mg/m3 for quartz and cristobalite.

Sampling and Analytical Methods

Current sampling and analytical methods used to evaluate occupational exposure to respirable crystalline silica

do not meet the accuracy criterion needed to quantify exposures at

concentrations below 0.05 mg/m3.

There is need for new, more sensitive, and more accurate

methods to monitor occupational exposure to crystalline silica.

Cyclone is used to remove larger particles.

Respirable fraction is collected on PVC filter.

Sampling Crystalline Silica

www.osha.gov

Operates at a flow rate 2 to 3 times higher than currently available

respirable samplers

The objective of this study was to develop and test a personal respirable sampler that:

Follows respirable convention accurately

Performance of Six Respirable Cyclones

Aluminum

Dorr-Oliver GS-1 GS-3

BGI-4CP SIMPED

Aerodynamic Particle Diameter, da, m

0 2 4 6 8 10S

am

plin

g E

ffic

ien

cy

, E,

%

0

25

50

75

100

Respirable Convention

GS-3 Cyclone, QS=2.75 L/min

Test Aerosol:

DOP Glass Spheres Coal Mine Dust

Aerodynamic Particle Diameter, da, m

0 2 4 6 8 10

Sam

plin

g E

ffic

ien

cy, E

, %

0

25

50

75

100

Respirable Convention

Aluminum Cyclone, QS=2.5 L/min

Test Aerosol:

DOP Glass Spheres Coal Mine Dust

Aerodynamic Particle Diameter, da, m

0 2 4 6 8 10

Pen

etra

tio

n, P

, %

0

25

50

75

100

Respirable Convention

Single Impactor: d50=4.0 m

Two impactors: d50=5.6, and 2.9 m

Four impactors: d50=6.6, 4.6, 3.5, and 2.2 m

Six impactors: d50=7.1, 5.4, 4.4, 3.7, 3.0, and 1.8 m

Simulation of Respirable Curve Using Impactors

Aerodynamic Particle Diameter, da, m

0 2 4 6 8 10 12

Pen

etr

ati

on

, P, %

0

25

50

75

100

HD Cyclone, QS=2.2 L/min

Respirable Convention

PPI, QS=2.0 L/min

Performance of SKC Parallel Particle Impactor

Performance of Individual Impactors of High Flow PPI

Performance of High Flow Parallel Particle Impactor

Experimental Setup

%100)(

)()(

dC

dCdE

Up

Down

Clean Air(50 Lpm )

VirtualIm pactor

ChargeNeutralizer

TurbulenceGenerators

Honeycom bFlow Straightener

Clear PlexiglassCylinder

(D=12 , H=48 )” ”

AccessPort

Foam

Sam plingLines

BallValve

TestDevice

To Filter

M akeup Flow

AerosolGenerator

Aerodynam icParticle Sizer

(APS 3320)

Inlet

Exhaust

ImpactionPlate

SKC Parallel Particle Impactor

SKC High Flow PPI

Conclusions

o High flow personal respirable sampler was developed and shown to match the entire ACGIH/CEN/ISO respirable curve closely.

o The newly developed respirable sampler in conjunction with a high flow personal sample pump can be used to accurately measure occupational exposure to respirable crystalline silica when new lower exposure limits need to be met.

Thank You!