Heat & Ventilation

Heat 

     Heat is a form of energy which produces a change in the temperature of any substance. In simple language ‘Heat is defined as the flow of energy from a warm to a cooler object’. The direction of flow of the heat energy takes from the substance of higher temperature to the substance of lower temperature.

    Also, the temperature is the average kinetic energy per molecule of that substance. Temperature is measured in different scales as Celsius (C), Fahrenheit (F) and Kelvins (K).

Ventilation

      ‘Ventilation refers to the process of removal of stale air/gas from a building, room or a confined space and replacing it with natural fresh air.’ 

• Systemic disorders:       Also can be called as physical hazards (i.e. heat exhaustion, heat/ water and salt deficiency).
• Skin disorder:      heat prickle, sweating deficiency, cancers of skin.
• Psychoneurotic disorder:  chronic heat, fatigue, loss of emotional control.

Factories Act 1948 requires affective and suitable provision in every factory for securing and maintaining proper temperature and ventilation.

The Factory Act 1948 requires the following:

• In any factory the maximum temperature of air at workplace should be around 30^oC and a work room at a height of 1.5 mtr above floor level and adequate air movement of at least 30 mtr per min (MPM) shall be provided.
• Fresh air should be supplied by mechanical ventilation in an hour shall be 6 times the cubic capacity of the work room.
• Ventilation is an engineering control to improving the quality of air and safety of employees.
• Ventilation can the work and increase productivity.
• Ventilation can improve the work environment by protecting workers from asthma and emphysema.

Industrial Ventilation 

Industrial ventilation is the mechanical system of building that brings in fresh outdoor air which removes “contaminants” indoor air. In a workplace ventilation is used to control exposure to air borne contaminates. If it commonly used to remove contaminates such as fumes, dust and vapor in order to provide a healthy and safe working environment. Ventilation can be obtained by “natural” means window or “mechanical” means blowers, fans.

Purpose of Ventilation System

1. Provide a continuous supply of fresh outside air.
2. Maintained temperature and humidity at comfortable level.
3. Reduce potential fire or explosion hazards Remove or dilute airborne contaminants.

Importance of Ventilation System

Ventilation is considered in engineering control to remove or control contaminants released in indoor work environment.

Other ways to Control Contaminants (Hierarchy of Control)

1. Eliminate the use of hazardous chemical.
2. Substitute with less toxic materials.
3. Process change.
4. Work practice change.

Types of Ventilation System

1.    General ventilation system (Dilution):        General exhaust ventilation also called dilution ventilation is different from local exhaust ventilation because instead of removing air contaminants from the air. General ventilation allows the contaminating to be emitted into the workplace and the acceptable level.

2.    Local exhaust ventilation (LEV):       LEV captures contaminants at or very near the source and exhausts then outside. LEV has 6 basic elements:

• A “hood” on opening that contains captures the contaminants at the source.
• “Ducts” that transplant the airborne chemical through the system.
• An “air cleaning device” that remove the contaminant from the moving air in the system.
• “Fans” that move the air though the system and discharge the exhausts air outdoors.
• An “exhaust stack” through which the contaminant air is discharged.
• “Make up air” that replaces the exhaust air.

HVAC (Heating Ventilating and Air Conditioning)

    Heating, ventilation, and air conditioning is the use of various technologies (i.e., mechanical, electrical and I & C components) to control the temperature, humidity and purity of the air in an enclosed space. 

    HVAC system is basically an assembly of various types of equipment installed together to provide heating and cooling along with indoor climate control. HVAC system provide thermal comfort and acceptable air quality to the occupants of building/space or to preserve goods, products or items placed in space.

    HVAC system design is a subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics, and heat transfer. HVAC is also used for order control and maintenance of acceptable concentration of carbon dioxide.