OSHA Respirable Crystalline Silica Standard Update
OSHA Respirable Crystalline Silica Standard Update Source and Control: 3A Identify Sources 3B Investigate and Evaluate Control Options and Develop Engineering Plans 3C Implement the Control Plan www.afsinc.org │ CastingConnection.afsinc.org │ @AmerFoundrySoc
Exposure Control Error #1 “Out of sight out of mind” • Visible dust is an imperfect surrogate for respirable dust. • For reference Respirable particles • Visible >80 microns (PM4) are not visible • Human hair (>50) • Fine sand grain (~100)
PM4= sample device collects 50% of 4 micron diameter particles
www.afsinc.org │ CastingConnection.afsinc.org │ @AmerFoundrySoc
Out of sight, out of mind… • Just because you don’t see dust doesn’t mean it’s not there! • Respirable particles are not visible • “Floaters” are a clue!
www.afsinc.org │ CastingConnection.afsinc.org │ @AmerFoundrySoc
3A- Identify Sources • Finding dust sources takes time • • • •
Process knowledge Look Instrumentation Engineering
www.afsinc.org │ CastingConnection.afsinc.org │ @AmerFoundrySoc
Process Knowledge • Common Sources of Respirable Dust • • • • • • • • • • • • • •
Shakeout (vibration and turbulence) Knockoff/sorting Vibrating conveyors Conveyor transitions Grinding Leaks in sand systems / abrasive blast systems Leaks in dust collection systems Compressed air Sand spillage Crane bays handling sprue returns Foot and vehicle traffic Refractory repair Floor sweepers Housekeeping activities www.afsinc.org │ CastingConnection.afsinc.org │ @AmerFoundrySoc
Process Knowledge
Shakeout Knock-off/sorting Grinding Based on industry experience, these are all known sources of respirable silica Refractory Repair www.afsinc.org │ CastingConnection.afsinc.org │ @AmerFoundrySoc
Look • Where is visible dust generated? • A fraction may be respirable • Strong light can help to see floaters
• Where is fine dust accumulating? • Do existing systems need maintenance? • Curtains, duct leaks, plugged ducts, ventilation balance
• Where are housekeeping activities stirring dust?
www.afsinc.org │ CastingConnection.afsinc.org │ @AmerFoundrySoc
Look For Potential Sources Basements
www.afsinc.org │ CastingConnection.afsinc.org │ @AmerFoundrySoc
Look For Potential Sources Sand spillage and build-up
www.afsinc.org │ CastingConnection.afsinc.org │ @AmerFoundrySoc
Look For Potential Sources Leaks in ventilation systems
www.afsinc.org │ CastingConnection.afsinc.org │ @AmerFoundrySoc
Look For Potential Sources Leaks in ventilation systems
www.afsinc.org │ CastingConnection.afsinc.org │ @AmerFoundrySoc
Look For Potential Sources Leaks in ventilation systems Maintain your existing systems Torn/missing curtains
Damaged enclosures
Fans disrupting airflow www.afsinc.org │ CastingConnection.afsinc.org │ @AmerFoundrySoc
Instrumentation • Real time respirable silica measurement is NOT currently available • Real time respirable particulate monitors are available that measure total respirable particulate, but only part of that may be silica • Respirable dust monitoring can, however, help provide clues as to sources • More respirable dust may mean more silica
www.afsinc.org │ CastingConnection.afsinc.org │ @AmerFoundrySoc
Engineering • Engineering firms are beginning to offer analysis and control help • Dust mapping • Maps produced from real time measurements of respirable particulate matter (RPM) with concurrent background samples for respirable silica to correlate RPM concentrations with silica content of the dust.
• Root cause analysis involving personal real time sampling to identify task-related components of the silica exposure. • This RPM sampling is correlated with the silica content estimated using the foundry’s TWA compliance sampling results.
• Ventilation analysis • Ventilation upgrades
www.afsinc.org │ CastingConnection.afsinc.org │ @AmerFoundrySoc
Exposure Control Error #1 “Out of sight out of mind” • Visible dust is an imperfect surrogate for respirable dust. • For reference Respirable particles • Visible >80 microns (PM4) are not visible • Human hair (>50) • Fine sand grain (~100)
PM4= sample device collects 50% of 4 micron diameter particles
www.afsinc.org │ CastingConnection.afsinc.org │ @AmerFoundrySoc
Out of sight, out of mind… • Just because you don’t see dust doesn’t mean it’s not there! • Respirable particles are not visible • “Floaters” are a clue!
www.afsinc.org │ CastingConnection.afsinc.org │ @AmerFoundrySoc
3A- Identify Sources • Finding dust sources takes time • • • •
Process knowledge Look Instrumentation Engineering
www.afsinc.org │ CastingConnection.afsinc.org │ @AmerFoundrySoc
Process Knowledge • Common Sources of Respirable Dust • • • • • • • • • • • • • •
Shakeout (vibration and turbulence) Knockoff/sorting Vibrating conveyors Conveyor transitions Grinding Leaks in sand systems / abrasive blast systems Leaks in dust collection systems Compressed air Sand spillage Crane bays handling sprue returns Foot and vehicle traffic Refractory repair Floor sweepers Housekeeping activities www.afsinc.org │ CastingConnection.afsinc.org │ @AmerFoundrySoc
Process Knowledge
Shakeout Knock-off/sorting Grinding Based on industry experience, these are all known sources of respirable silica Refractory Repair www.afsinc.org │ CastingConnection.afsinc.org │ @AmerFoundrySoc
Look • Where is visible dust generated? • A fraction may be respirable • Strong light can help to see floaters
• Where is fine dust accumulating? • Do existing systems need maintenance? • Curtains, duct leaks, plugged ducts, ventilation balance
• Where are housekeeping activities stirring dust?
www.afsinc.org │ CastingConnection.afsinc.org │ @AmerFoundrySoc
Look For Potential Sources Basements
www.afsinc.org │ CastingConnection.afsinc.org │ @AmerFoundrySoc
Look For Potential Sources Sand spillage and build-up
www.afsinc.org │ CastingConnection.afsinc.org │ @AmerFoundrySoc
Look For Potential Sources Leaks in ventilation systems
www.afsinc.org │ CastingConnection.afsinc.org │ @AmerFoundrySoc
Look For Potential Sources Leaks in ventilation systems
www.afsinc.org │ CastingConnection.afsinc.org │ @AmerFoundrySoc
Look For Potential Sources Leaks in ventilation systems Maintain your existing systems Torn/missing curtains
Damaged enclosures
Fans disrupting airflow www.afsinc.org │ CastingConnection.afsinc.org │ @AmerFoundrySoc
Instrumentation • Real time respirable silica measurement is NOT currently available • Real time respirable particulate monitors are available that measure total respirable particulate, but only part of that may be silica • Respirable dust monitoring can, however, help provide clues as to sources • More respirable dust may mean more silica
www.afsinc.org │ CastingConnection.afsinc.org │ @AmerFoundrySoc
Engineering • Engineering firms are beginning to offer analysis and control help • Dust mapping • Maps produced from real time measurements of respirable particulate matter (RPM) with concurrent background samples for respirable silica to correlate RPM concentrations with silica content of the dust.
• Root cause analysis involving personal real time sampling to identify task-related components of the silica exposure. • This RPM sampling is correlated with the silica content estimated using the foundry’s TWA compliance sampling results.
• Ventilation analysis • Ventilation upgrades
www.afsinc.org │ CastingConnection.afsinc.org │ @AmerFoundrySoc
