spray application with isocyanates. historical review of the water tanks
TRANSCRIPT
Spray Application with Isocyanates
HISTORICAL REVIEW OF THE WATER TANKS
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July 9, 1964• Water
Tanks• 9’ tall• 40’ long• Direct
bury
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Tanks (left)
50 YEARS LATER
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Tank Room
WHAT IS SPRAY MATERIAL?Part A + Part B
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MDI FormsPart A is 4,4’ MDI (100%)
ISSUES AND RESOLUTIONS
What is this material found around tanks?
MDI SAMPLING PROTOCOLS
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4,4'-diphenylmethane diisocyanate (MDI) MDI Sampling Methods
• MDI has a very low vapor pressure (good) and very reactive (good/bad). So, the vapor is not likely present outside the tank being sprayed, having reacted very quickly. Aerosols do exist and cause the same symptoms as vapor.
• MDI aerosol has many test methods. The one we chose was OR-OSHA Method 1010 calling for midget impingers, toluene-DMSO based solution and MAMA impregnated post-filter.
• Impingers are not conducive to tank entry (will spill contents on entrant), and have a high probability of being coated.
• Passive dosimeters and direct-reading instrument capture vapor, not aerosol. • We looked for 4,4’ MDI monomer, not oligomer.
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Monitoring for MDI Vapor
(colorimetric)
WHAT CONTROLS ARE USED?
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REDUCE FOOT TRAFFIC TO THE BASEMENTAccess Control
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SAMPLING METHODS
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Sampling Methods
1. Impinger2. Glass Fiber Filter, open
face3. Direct Reading Instrument4. Passive Dosimeters
RESULTS
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EXPOSURE RESULTS
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QUESTIONS? The work we do is vital
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