ventilation.pptx

Industrial safety for ventilation

1. PURPOSE & EFFECTS OF VENTILATION AND HEAT CONTROL Clean, fresh and uncontaminated air is a basic need of life. Industry has many pollutants which contaminate air and heat stress is generated due to hot processes. Well designed and effective ventilation provides solution to these problems .

2. Purpose of Ventilation and Heat Control: Air is life and fresh air is the first need for survival of living creatures. Absence of air brings death within a few minutes. Life without breathing is not possible and the clean air is needed for the whole life- for breathing and functioning of human body. Therefore good ventilation giving sufficient fresh air is the permanent requirement . 2. Human body cannot tolerate excessive temperature. Heat stresses produced by very hot or cold exposures cause adverse effects on health and safety of work people. Therefore environmental temperature control is also permanently needed for well functioning of human body . Ventilation helps in removing excessive temperature 3. Heavy physical work or heavy work load causes heat stress and strain and increase metabolic heat, body temperature, sweating, heart rate etc. To maintain (control) body temperature, ventilation is necessary.

3. Purpose of Ventilation and Heat Control(Cont) 4. Carbon dioxide is continuously exhausted by all human beings. Much more contaminants are added by manufacturing processes to pollute air. Therefore cleaning of air and supply of fresh air with sufficient oxygen are also necessary. This is possible by good ventilation and pollution control techniques only . 5. Where due to weather or atmospheric conditions or process parameters, excessive temperature is unbearable or uncomfortable, air conditioning or HVAC systems are also necessary. Conversely where air heating is necessary as in case of excessive cold climate, it must be provided. 6. Basic functions of ventilation are to (a) maintain the oxygen content of the air and to prevent CO, concentrations from rising (b) prevent or removal of body odours (c) prevent harmful concentration of aerosols and air-borne contaminants and (d) maintain reasonable conditions of thermal limits for comfort and efficiency which result in decreased heat stress, increased productivity, reduced accident rates (hot conditions induce unsafe acts) and adverse health effects (interaction with other hazards), higher level of job satisfaction, reduced absenteeism, improved attitudes, reduced downtime for hot vessels and compliance of required standards.

4. Cont… 7. While designing industrial buildings care must be taken to- 1.provide good ventilation for dilution of inside air to prevent vitiation by causes, such as body odours , 2. remove process released contaminants and heat exposures 3.maintain satisfactory thermal environments , 4. maintain heat balance of body and 5. prevent acute discomfort and injury to the health of the workers . If natural ventilation is not sufficient for these purposes, mechanical ventilation, cooling system or other techniques must be employed to achieve satisfactory results . Thus main purpose of ventilation is to remove heat 'and contaminants from air in residential or industrial building and to supply or regulate fresh and cool (or hot) air for the comfort of the occupants or workers.

5. The quantity and quality of air required for ventilation depend upon 1.Rates of heat generation in the room. 2. Rates of contaminants (gas, vapour, dust) generation in the room. 3. Rates of dispersion of heat & contaminant. 4. Rates of dilution and removal that may be achieved by ventilation. 5. Electric fittings for ventilation system in flammable/explosive area should be flameproof and of the approved type.

6. Effects of Good and Bad Ventilation: Effects of good ventilation are: 1. Availability of sufficient fresh air for breathing or life. 2. Removing oxygen deficiency from a confined space. 3. Removal or dilution of carbon dioxide and other air pollutions. 4. Decrease in environmental heat or temperature. 5. Increase in air changes per hour as per statutory requirement. 6. Maintaining metabolic body temperature or heat balance . 7. Removal of air contaminants (dust, gas, fumes, mist etc) from work room. 8. Maintaining room temperature for comfort.

7. Cont… 9. Providing desired air conditioning (cooling or heating). 10. Removal of body odour and bad smell from the room. 11. After heavy physical work, evaporating body sweating and making the body cool. 12. Decreasing discomfort and distress.13 . Maintaining efficiency of work. 14. Decreasing chances of accidents and maintaining safety and productivity. 15. Providing better job satisfaction and good attitudes. 16. Increasing cooling rate of hot vessels or hot substances. 17. To maintain overall comfortable working conditions and 18. To help compliance of statutory provisions and standards.

8. Effects of bad ventilation Effects of bad ventilation are opposite to above non availability of fresh air for life, insufficient air changes no cooling effect discomfort, body stress and strain no removal of air contaminants, body odour, bad smell etc , increasing chances of accidents, lowering efficiency and productivity no job satisfaction more time for cooling of hot vessel and substances and violation of statutory provisions etc.