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Chemwatch:4650-8 Page 6 of 14 Issue Date:11/12/2018 Version No:6.1.1.1 API Pond Ammonia Test Solution#2 Print Date:06/21/2019 Engineering controls are used to remove a hazard or place a barrier between the worker and the hazard.Well-designed engineering controls can be highly effective in protecting workers and will typically be independent of worker interactions to provide this high level of protection. The basic types of engineering controls are: Process controls which involve changing the way a job activity or process is done to reduce the risk. Enclosure and/or isolation of emission source which keeps a selected hazard"physically"away from the worker and ventilation that strategically"adds"and'removes"air in the work environment.Ventilation can remove or dilute an air contaminant if designed properly.The design of a ventilation system must match the particular process and chemical or contaminant in use. Employers may need to use multiple types of controls to prevent employee overexposure. Local exhaust ventilation usually required.If risk of overexposure exists,wear approved respirator.Correct fit is essential to obtain adequate protection.Supplied-air type respirator may be required in special circumstances.Correct fit is essential to ensure adequate protection. An approved self contained breathing apparatus(SCBA)may be required in some situations. Provide adequate ventilation in warehouse or closed storage area.Air contaminants generated in the workplace possess varying"escape"velocities which,in turn,determine the"capture velocities"of fresh circulating air required to effectively remove the contaminant. Type of Contaminant: Air Speed: solvent,vapours,degreasing etc.,evaporating from tank(in still air). 0.25-0.5 m/s (50-100 f/min.) Appropriate engineering aerosols,fumes from pouring operations,intermittent container filling,low speed conveyer 0.5-1 m/s controls transfers,welding,spray drift,plating acid fumes,pickling(released at low velocity into zone of active generation) (100-200 f/min.) direct spray,spray painting in shallow booths,drum filling,conveyer loading,crusher dusts,gas 1-2.5 m/s discharge(active generation into zone of rapid air motion) (200-500 f/min.) grinding,abrasive blasting,tumbling,high speed wheel generated dusts(released at high initial 2.5-10 m/s velocity into zone of very high rapid air motion). (500-2000 f/min.) Within each range the appropriate value depends on: i Lower end of the range Upper end of the range 1:Room air currents minimal or favourable to capture 1:Disturbing room air currents 2:Contaminants of low toxicity or of nuisance value only. 2:Contaminants of high toxicity r3:Intermittent,low production. 3:High production,heavy use 4:Large hood or large air mass in motion 4:Small hood-local control only Simple theory shows that air velocity falls rapidly with distance away from the opening of a simple extraction pipe. Velocity generally decreases with the square of distance from the extraction point(in simple cases).Therefore the air speed at the extraction point should be adjusted,accordingly,after reference to distance from the contaminating source. The air velocity at the extraction fan,for example,should be a minimum of 1-2 m/s(200-400 f/min)for extraction of solvents generated in a tank 2 meters distant from the extraction point.Other mechanical considerations,producing performance deficits within the extraction apparatus,make it essential that theoretical air velocities are multiplied by factors of 10 or more when extraction systems are installed or used. 000 Personal protection [�(� Safety glasses with unperforated side shields may be used where continuous eye protection is desirable,as in laboratories;spectacles are not sufficient where complete eye protection is needed such as when handling bulk-quantities,where there is a danger of splashing,or if the material may be under pressure. Chemical goggles.whenever there is a danger of the material coming in contact with the eyes;goggles must be properly fitted. Full face shield(20 cm,8 in minimum)may be required for supplementary but never for primary protection of eyes; these afford face protection. Alternatively a gas mask may replace splash goggles and face shields. Eye and face protection Contact lenses may pose a special hazard;soft contact lenses may absorb and concentrate irritants.A written policy document,describing the wearing of lenses or restrictions on use,should be created for each workplace or task.This should include a review of lens absorption and adsorption for the class of chemicals in use and an account of injury experience.Medical and first-aid personnel should be trained in their removal and suitable equipment should be readily available.In the event of chemical exposure,begin eye irrigation immediately and remove contact lens as soon as practicable.Lens should be removed at the first signs of eye redness or irritation-lens should be removed in a clean environment only after workers have washed hands thoroughly.[CDC NIOSH Current Intelligence Bulletin 59],[AS/NZS 1336 or national equivalent] Skin protection See Hand protection below Continued...