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TECHNIQUES IN TECHNOLOGY
IN TANDEM WITH
TECHNIQUES IN OPERATION
courtesy Vigan Engineering-Unloading Tapioca
DUST DEFINITIONS
Small solid particles, conventionally taken as those particles below 75 μm in diameter, which settle out under their own weight but which may remain suspended for some time.
Dust particles are usually in the size range from about 1 to 100 μm in diameter, and they settle slowlyunder the influence of gravity.
Particle Sizes
• Cement dust 3-100 microns (1/1000mm)• Coal dust 5-1000• Iron dust 4-50• Atmospheric dust 0.001 -40• Grain dust 5-1000• Human hair 70• Flour 1-100Human eye can see 40 micron and higher dust
Operation Dust levels(mg.m-3)
Unloading ship 1-14using bucket elevators Elevator operating 1.5-7(in cabin) On quay adjacent to 69-267 barge being loaded Driving vehicle 13-32in hold of Ship Cleaning holds and 14-23quays Loading lorries Discharging 1-30lorries People in vicinity 1 -6of operations
A dust is considered to be hazardous to health if:
- it has an occupational exposure limit, ie it has been given - an occupational exposure standard or a maximum exposure limit
- it is present at a substantial concentration in air, ie more than 10 mg.m-3 (total inhalable) or 4 mg.m-3 (respirable)
- it is classified as dangerous to health (ie as very toxic,toxic, harmful, corrosive or irritant)
- it is a biological agent, ie it contains bacteria or othermicrobiological organisms
Allowable dust concentrations for humans PM10 (average 10 micron particles)50 μg/m3 allowable exposure per day over the course of 1 year150 μg/m3 allowable exposure over 24 hours
PORT HANDLING ACTIVITY REVOLVES AROUND DUST PARTICLES OF ABOUT 1-1000 MICRONS SIZE.
MEASUREMENT
• Opacity is primary measurement technique for dust emission
• EPA (Environmental Protection Agency USA) 9 is the opacity standard
• Measurement is by trained investigator who compares opacity with standard charts
• Readings are averaged out as per procedure
OPERATIONAL CHAIN• Local Government• Port Authority• Port Managers• Unloading contractor• Crane hire agency• Crane operator• Despatch agency• Equipment owners
• Compliances– Dust levels– Unloading schedules– Operator health and
safety– Operator training– Port regulations– Local Govt regulations– Product integrity
SUMMARY OF RECOMMENDATIONS• Each case is unique-
needs discussion with port authorities and technology/equipment suppliers
• Dust control must be treated on par with loading and unloading operations-as revenue earners
• All concerned-port, union, vendor, operators have to discuss and prepare operation manual
• Ship crane operators should be given pre-unloading briefing
• Equipment suppliers must build in feedback loops for operators
SUMMARY OF RECOMMENDATIONS• Measuring
instrumentation is essential with reports
• Operators must have periodic medical examination
• Separate department must be formed with managerial responsbility
• Clear policy and management
• Standard operating procedures
• Top management commitment
• Quick decision making• Training and awareness• Involve operating
personnel 100%
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