Bob Lacovara, CCM, CCT-I Convergent Composites 1.

1

Combustible DustComposites Manufacturing Issues

Bob Lacovara, CCM, CCT-I

Convergent Composites

LIMITING WORKERSTYRENE EXPOSURE

http://www.acmashow.org/


© Convergent Composites 2011

PPEMoldingProcess

EngineeringControls

MaterialsSelection

Elements ofExposure Control

Styrene Exposure Reduction



Materials Technology

Polyester Resin

EPOXY RESIN



Materials Technology• Styrene Suppressants




• Low Styrene Resins LS Polyester

Resin




• Low Styrene Resins

• Alternative Monomers






• Epoxy Resins

EPOXY RESIN






• Epoxy Resins

• Thermoplastics



Emissions Limiting Processes



Process Technology• Non-Spray Application




• Vacuum Infusion




• Vacuum Infusion

• RTM Processing




• Vacuum Infusion

• RTM Processing

• Pre-Preg Processing




• Vacuum Infusion

• RTM Processing


• Polyester Pre-Preg




• Vacuum Infusion

• RTM Processing


• Polyester Pre-Preg

• Robotic Application



Control Technology



Control Technology• Best Practice Ventilation



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



General VentilationDilution ventilation moves the entire

volume of air within a work space



Enhanced VentilationDesigned to move air specifically from

breathing and emissions producing zones



Control TechnologyEnhanced Ventilation Example

Filament Winding Application



Open Molding Application




Hull Molding Application




Work Practice Control

C 1T 1

+ C 2T 2

+ C 3T 3

8 Hrs

Exposure =



Work Practice Control• Clean Operations Training



Work Practice Control• Clean Operations Training

• Operator Positioning



Spray Booth

OperatorPositioned

Upwind

Air Flow

Operator Positioning



Administrative Control• Work Habit Training

• Operator Positioning

• Time Limited Exposure



Administrative ControlTWA Calculation

C1T1 + C2T2 + C3T3

8 HrsExposure =

Exposure = Time Weighted Avg (TWA)

C = Concentration (ppm)

T = Time (hours)



TWA Calculation(50 ppm TWA)

Measured Exposure: 2-hours @ 70 ppm

2-hours @ 50 ppm

4-hours @ 40 ppm

(70 x 2) + (50 x 2) + (40 x 4)

8 Hrs=

400

8= 50 ppm TWA



TWA Calculation(20 ppm TWA)


2-hours @ 30 ppm

4-hours @ 0 ppm

(50 x 2) + (30 x 2) + (0 x 4)

8 Hrs=

160

8= 20 ppm TWA



TWA Calculation


2-hours @ 50 ppm

4-hours @ 40 ppm

400 ppm units/day

Current 50 ppm TWAlooks like this:


2-hours @ 30 ppm

4-hours @ 0 ppm

160 ppm units/day

Proposed 20 ppm TWAlooks like this:



Time Limited ExposureScenario: Four Workers - Three Different Jobs

Operator Designations

WorkTasks

TimeBlocks

Exposure Level

Worker “A” Spray Gun Operator 2- Hours 50 - ppm

Worker “B” Laminator - Roll Out 2 - Hours 30 - ppm

Worker “C” Finish Sanding 2 - Hours 0.0 - ppm

Worker “D” Finish Sanding 2 - Hours 0.0 - ppm



The Reality of Crew Rotation4-Workers / 3-Jobs - Spraying - Laminating - Finishing

50 ppm - 2 hrs / 30 ppm - 2 hrs / 0 ppm - 4 hrs

2Hr. Cycle

1

• Worker A - Spray

• Worker B - Roll Out

• Worker C - Finish

• Worker D - Finish

2Hr. Cycle

2

• Worker B - Spray

• Worker A - Roll Out

• Worker C - Finish

• Worker D - Finish

2 Hr. Cycle

4

• Worker D - Spray

• Worker C - Roll Out

• Worker A - Finish

• Worker B - Finish

2Hr. Cycle

3

• Worker C - Spray

• Worker D - Roll Out

• Worker A - Finish

• Worker B - Finish



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

SUMMARY:

36

Combustible DustComposites Manufacturing Issues

LIMITING WORKERSTYRENE EXPOSURE

Contact:Bob Lacovara, CCM, CCT-I

Convergent [email protected]

www.convergentcomposites.com

mailto:[email protected]



Bob Lacovara, CCM, CCT-I Convergent Composites 1.

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