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LIMITING WORKER STYRENE EXPOSURE. Combustible Dust. Composites Manufacturing Issues. Bob Lacovara, CCM, CCT-I Convergent Composites. Styrene Exposure Reduction. Elements of. Exposure Control. Molding Process. PPE. Engineering Controls. Materials Selection.
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LIMITING WORKER STYRENE EXPOSURE Combustible Dust Composites Manufacturing Issues Bob Lacovara, CCM, CCT-I Convergent Composites
Styrene Exposure Reduction Elements of Exposure Control Molding Process PPE Engineering Controls Materials Selection
Styrene Exposure Reduction Materials Technology Polyester Resin EPOXY RESIN
Styrene Exposure Reduction Materials Technology • Styrene Suppressants
Styrene Exposure Reduction Materials Technology • Styrene Suppressants • Low Styrene Resins LS Polyester Resin
Styrene Exposure Reduction Materials Technology • Styrene Suppressants • Low Styrene Resins • Alternative Monomers
Styrene Exposure Reduction Materials Technology • Styrene Suppressants • Low Styrene Resins • Alternative Monomers • Epoxy Resins EPOXY RESIN
Styrene Exposure Reduction Materials Technology • Styrene Suppressants • Low Styrene Resins • Alternative Monomers • Epoxy Resins • Thermoplastics
Styrene Exposure Reduction Emissions Limiting Processes
Styrene Exposure Reduction Process Technology • Non-Spray Application
Styrene Exposure Reduction Process Technology • Non-Spray Application • Vacuum Infusion
Styrene Exposure Reduction Process Technology • Non-Spray Application • Vacuum Infusion • RTM Processing
Styrene Exposure Reduction Process Technology • Non-Spray Application • Vacuum Infusion • RTM Processing • Pre-Preg Processing
Styrene Exposure Reduction Process Technology • Non-Spray Application • Vacuum Infusion • RTM Processing • Pre-Preg Processing • Polyester Pre-Preg
Styrene Exposure Reduction Process Technology • Non-Spray Application • Vacuum Infusion • RTM Processing • Pre-Preg Processing • Polyester Pre-Preg • Robotic Application
Styrene Exposure Reduction Control Technology
Styrene Exposure Reduction Control Technology • Best Practice Ventilation
Styrene Exposure Reduction Control Technology • With general ventilation (aka, dilution ventilation) • it will be difficult to produce a 20 ppm environment • Enhanced ventilation will be required in most cases • to technically and cost effectively address 20 ppm
Styrene Exposure Reduction General Ventilation Dilution ventilation moves the entire volume of air within a work space
Styrene Exposure Reduction Enhanced Ventilation Designed to move air specifically from breathing and emissions producing zones
Styrene Exposure Reduction Control Technology • Enhanced Ventilation Example Filament Winding Application
Styrene Exposure Reduction Control Technology • Enhanced Ventilation Example Open Molding Application
Styrene Exposure Reduction Control Technology • Enhanced Ventilation Example Hull Molding Application
Styrene Exposure Reduction Work Practice Control C1T1 + C2T2 + C3T3 Exposure = 8 Hrs
Styrene Exposure Reduction Work Practice Control • Clean Operations Training
Styrene Exposure Reduction Work Practice Control • Clean Operations Training • Operator Positioning
Styrene Exposure Reduction Operator Positioning Air Flow Operator Positioned Upwind Spray Booth
Styrene Exposure Reduction Administrative Control • Work Habit Training • Operator Positioning • Time Limited Exposure
Styrene Exposure Reduction Administrative Control TWA Calculation C1T1 + C2T2 + C3T3 Exposure = 8 Hrs Exposure = Time Weighted Avg (TWA) C = Concentration (ppm) T = Time (hours)
Styrene Exposure Reduction • Measured Exposure: • 2-hours @ 70 ppm • 2-hours @ 50 ppm • 4-hours @ 40 ppm TWA Calculation (50 ppm TWA) (70 x 2) + (50 x 2) + (40 x 4) 400 = = 50 ppm TWA 8 8 Hrs
Styrene Exposure Reduction • Measured Exposure: • 2-hours @ 50 ppm • 2-hours @ 30 ppm • 4-hours @ 0 ppm TWA Calculation (20 ppm TWA) (50 x 2) + (30 x 2) + (0 x 4) 160 = = 20 ppm TWA 8 8 Hrs
Styrene Exposure Reduction TWA Calculation Proposed 20 ppm TWA looks like this: Current 50 ppm TWA looks like this: • Measured Exposure: • 2-hours @ 70 ppm • 2-hours @ 50 ppm • 4-hours @ 40 ppm • 400 ppm units/day • Measured Exposure: • 2-hours @ 50 ppm • 2-hours @ 30 ppm • 4-hours @ 0 ppm • 160 ppm units/day
Styrene Exposure Reduction Time Limited Exposure Scenario: Four Workers - Three Different Jobs
Styrene Exposure Reduction The Reality of Crew Rotation 4-Workers / 3-Jobs - Spraying - Laminating - Finishing 50 ppm - 2 hrs / 30 ppm - 2 hrs / 0 ppm - 4 hrs 2Hr. Cycle 1 2Hr. Cycle 2 2Hr. Cycle 3 2 Hr. Cycle 4 • Worker A - Spray • Worker B - Roll Out • Worker C - Finish • Worker D - Finish • Worker B - Spray • Worker A - Roll Out • Worker C - Finish • Worker D - Finish • Worker C - Spray • Worker D - Roll Out • Worker A - Finish • Worker B - Finish • Worker D - Spray • Worker C - Roll Out • Worker A - Finish • Worker B - Finish
Styrene Exposure Reduction SUMMARY: An exposure limit of 20 ppm TWA will require a combination of technologies & work practices • Low emissions materials • Emissions limiting processes • Enhanced ventilation • Enhanced work practices
LIMITING WORKER STYRENE EXPOSURE Combustible Dust Composites Manufacturing Issues Contact: Bob Lacovara, CCM, CCT-I Convergent Composites blacovara@aol.com www.convergentcomposites.com