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Today’s article is about “What is HVAC System and How does it Function?” This is a very basic article about the functioning of an HVAC system. It will help you understand HVAC; especially those who are seeking a career in this particular field.
What is HVAC?
HVAC stands for heating, ventilation, and air conditioning. This system provides heating and cooling to residential as well as commercial buildings. Earlier it was considered a luxury but now it has become a necessity. From your air conditioner at home to the large systems used in industrial complexes and apartment blocks, HVAC is everywhere.
Functions of HVAC System:-
HVAC aims to make personnel comfortable and to maintain conditions required by a product or process within a space. It protects workers inside a facility and products that might be sensitive to temperature, humidity, and airborne contamination from outside sources or cross-contamination between products. It provides protection of the environment outside a facility from airborne materials that could be hazardous.
Understanding the product and process is the key to good HVAC design. HVAC system performs four basic functions:
1. Maintain Temperature – HVAC maintains the temperature to provide human comfort. Also, in industries, the temperature can affect production directly or indirectly by fostering the growth of microbial contaminants on workers.
2. Maintain Moisture (Relative Humidity) – Humidity is controlled by cooling air to dew point temperatures or by using desiccant dehumidifiers. For hygroscopic materials, like powder or tablets, humidity can affect the efficacy and stability of drugs and is sometimes important to effectively mold the tablets.
Note: Comfortable personnel produces fewer environmental contaminants: a typical worker will discharge 100,000 particles (sized 0.3 μm and larger) a minute doing relatively sedentary work. A worker who is hot and uncomfortable may shed several million particles per minute in the size range, including a greater number of bacteria.
(Source: ISPE Good Practice Guide: HVAC)
3. Control Airborne Particles, Dust, and Micro-organisms – The concentration of total airborne particles and microbial contamination within the space is a key measurement of room environmental conditions. Process operators also need protection from exposure to airborne hazardous materials. HVAC system helps in controlling airborne particles thru air filtration using high-efficiency particulate air (HEPA) filters.
4. Maintain Room Pressure – A continuous flow of air in the desired direction through the cracks in building construction (door gaps, wall penetrations, conduits, etc.) reduces the unwanted passage of airborne particulates. Direction of airflow is usually controlled by the relative pressurization of adjacent spaces.
e.g. In a sterile facility, we have to maintain process areas “cleaner” than surrounding areas. That means these areas must be kept under “positive” pressurization, meaning that airflow must be from the “cleaner” area towards the adjoining space (through doors or other openings) to reduce the chance of airborne contamination.
On the other hand, in powder processing areas or areas handling potent products, surrounding areas must be kept under “positive” pressurization, so that product traces doesn’t come out of the processing room. In these types of facilities, the focus shifts from product safety to personnel safety. This is achieved by the HVAC system providing more air into the “cleaner” space than is mechanically removed from that space.
Note: If space is already contaminated, HVAC can not clean up the contaminated surfaces, contaminated room, or equipment.
So, friends, this was all about “What is HVAC System and How does it Function?”
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