Methods of Control

CONTROLTopic covered under various titles CONTROL of airborne hazards CONTROL of workplace contaminants/pollutants CONTROL of emissions and hazardous conditions CONTROL of emissions/hazards and worker conditions Prevention/Control of workplace hazards5 Fundamental control ASSUMPTIONS All hazards can be controlled Alternative approaches More than one control Some control are cost effective May not completely control the hazard Factors to consider in SELECTION of controls Effectiveness of controls Ease of use by worker Cost of controls Adequacy of warning properties of the material Acceptable level of exposure - TLV Frequency of exposure Route(s) of exposure Regulatory requirements for specific controls 3 CATEGORIES OF CONTROL METHODS Engineering - physical changes in machine, materials, process or operation Administrative - focus on the workers and policies Personal Protective Equipment - devices that protect certain parts of body from the hazard VENTILATIONadd or remove air from work areas; utilization of controlled flows flows of air Importance of ventilation in the workplace Control of health hazards (e.g. chemicals) Control of safety hazards (fire & explosion) Comfort Types of Ventilation as to SOURCE Natural Artificial Types of Ventilation SYSTEMS Supply Exhaust (Suction) Dilution Ventilation Application- General ventilationPrinciples Determine amount of air required for satisfactory dilution of air contaminant Locate the exhaust opening of the system near the source of contamination Locate the air supply and exhaust outlets such that air passes through zone of contamination Replace exhausted air by use of a replacement air system Avoid re-entry of the exhausted air by discharging it high above the roof line Exhaust Ventilation SystemMany hazards to be driven awayTypes and shapes of hoodsSelection of hood type Type of contaminant, mechanism for its generation Physical characteristics Interface: operator (worker) and equipment Hood design principlesCaptures hazard that needs to be eliminated Enclose operations Locate hood such as that the contaminant is moved away from the breathing zone of operator Shape hood such so the initial velocity directs or facilitates contaminant entry into hood (opening) Capture contaminant with the hood positioned as close as possible to the source Hood should be designed NOT to interfere with movements of the operator Hood Type Slot Flanged slot Plain opening Planged opening Booth Canopy