LOCAL EXHAUST

Nickel carbonyl should be used in totally enclosed systems or under good local exhaust. Plants and laboratories where nickel carbonyl is used should make use of air-monitoring devices, alarms should be present in case of accidental leakage, and appropriate personal respiratory protective devices should be readily available for emergency uses. Monitoring of urinary nickel levels is useful to help determine the severity of exposure and identify appropriate treatment measures. Some large-scale users of nickel carbonyl maintain a supply of sodium diethyldithiocarbamate, or Antabuse, a therapeutic agent, on hand for use in case of overexposure. 

It is good practice to keep concentrations of airborne nickel in any chemical form as low as possible and certainly below the relevant standard. Local exhaust ventilation is the preferred method, particularly for powders, but personal respirator protection may be employed where necessary. In the United States, the Occupational Safety and Health Administration (OSHA) personal exposure limit (PEL) for all forms of nickel except nickel carbonyl is 1 mg/m. The ACGIH TLVs are respectively 1 mg/m for Ni metal, insoluble compounds, and fume and dust from nickel sulfide roasting, and 0.1 mg/m for soluble nickel compounds. The ACGIH is considering whether to lower the TLVs for all forms of nickel to 0.05 mg/m, based on nonmalignant respiratory effects in experimental animals. 

Operations capable of generating airborne beryUium particulate, such as melting, machining, welding, grinding, etc, are effectively controUed by local exhaust ventilation or other control measures. To assure a safe environment and measure compliance with the OSHA standards, employee exposures should be periodicaUy measured by prescribed air sampling and analytical methods. 

Drying rotary oil- or gas-fired Particulates, SO2, NO, VOC, CO, and smoke Proper combustion controls, fuel-oil preheating where required local exhaust system, cyclone and a scrubber or baghouse... 

Dry processes materials handling, air separator (hot-air furnace) Particulates (dust) Local exhaust system with mechanical collectors and baghouse... 

Grinding Particulates (dust) Local exhaust system with cyclones... 

Pouring Zinc oxide fume, lead oxide fume cover high-zinc-content brass use of good combustion controls, local exhaust system, and baghouse or... 

Cadmium Roasters, slag, fuming furnaces, deleading Idlns Particulates Local exhaust system, baghouse or precipitator... 

RooBng plants (asphalt saturators) Felt or paper saturators spray section, asphalt tank, wet looper Crushed rock or other minerals handling Asphalt vapors and particulates (liquid) Particulates (dust) Exhaust system with high inlet velocity at hoods (3658 m/s [>200 ft/min]) with either scrubbers, baghouses, or two-stage low-voltage electrostatic precipitators Local exhaust system, cyclone or multiple cyclones... 

Provide local exhaust ventilation connected to a disposal system (vent condenser, adsorber, scrubber or incinerator)... 

As a standby for emergency use in case of accidental release of toxic materials, e.g. during tanker unloading, or disconnection of temporary pipelines or when dealing with spillages generally, or if other protective measures, e.g. local exhaust ventilation, fail in service. 

Dust from bulk fillers and whitings Local exhaust ventilation Care in handling... 

Dust from carbon black Master batches Local exhaust ventilation Totally enclosed systems Not by careful handling alone... 

Fume Local exhaust ventilation Removal of hot product from workroom -cool before handling... 

Calendering and extruding Fume Local exhaust ventilation Water cooling of extrudate... 

Curing Fume Local exhaust ventilation at autoclave door and storage racks Allow autoclave to cool before opening... 

Partial enclosure with local exhaust ventilation. 

Table 5.23 Frequency of thorough examination and test of local exhaust ventilation plant used in certain processes (Schedule 4, Reg. 9(2)(a)) ...

Provision and use of appropriate health surveillance, e.g. for signs of dermatitis, asthma, effects of specific solvent exposures. Full use of any spray booth, enclosure, exhaust ventilation or dilution systems, and automatic handling equipment. (The efficiency of all local exhaust ventilation and other control systems should be maintained, and checked by testing.) Where appropriate, atmospheric monitoring of airborne pollution levels. 

Provide and maintain efficient local exhaust ventilation, if enclosed plant cannot be used. 

The Occupational Exposure Standards imposed for trichloroethylene are Maximum Exposure Limits of 100 ppm (8 hr TWA) and 150 ppm (15 minute reference period). A skin notation Sk is applicable because of the potential for skin absorption. Because of its volatility, trichloroethylene is not recommended for cold cleaning it is normally used in partially enclosed vapour degreasing equipment provided with local exhaust ventilation. 

Partial enclosure with local exhaust ventilation, or local exhaust ventilation, of working position separate hazardous processes from other work, e.g. spray-painting with epoxy-containing sensitizing and carcinogenic compounds. 

Local exhaust vendladon serves to remove a contaminant near its source of emission into die atmosphere of a workplace. A system normally comprises a hood, ducting which conveys exhausted air and contaminants, a fan, equipment for contaminants collecdon/removal and a stack for dispersion of decontaminated air. Hoods normally comprise an enclosure, a boodi, a captor hood or a receptor hood. Those relying on odier dian complete enclosure should be as close as practicable to die source of polludon to achieve maximum efficiency. 

General conditions of work, e.g. maintenance of adequate general ventilation, local exhaust ventilation, access, lighting, fire precautions, occupational health measures, housekeeping. 

Local exhaust ventilation provisions (test and report at regular intervals)... 

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