Laboratory is a room or building equipped for scientific experiments, research, or teaching, or for the manufacture of drugs or chemicals. This facility provides controlled conditions in which scientific or technological research, experiments and measurement may be performed. In this place there are also workers who handle toxic and dangerous chemicals, harmful organisms, flammable solvents, combustible substances, obnoxious vapours, etc. Thus, setting a good and suitable ventilation is crucial for the safety and well being of the workers inside and or outside the building as well as the visitors.
Laboratory ventilation is a part of the Heating, Ventilation and Air Conditioning (HVAC) system. It displaces contaminated air and dilute it to safe levels, so fresh/air is supplied inside the building. It comprises two essential factors - air handling and filtration systems. There are two main types of ventilation used in research facilities and commercial labs that are natural ventilation and mechanical ventilation. Several key elements need to be analyzed before deciding which type of ventilation to use.
Natural ventilation relies on wind pressure to pump research labs full of fresh air through purpose-built openings including doors, solar chimneys, windows, wind towers and vents. This type of ventilation is hard to manage and control because when the openings are kept closed, the air becomes stagnant. That means it’s effectiveness can be dependent on things like building design, human behaviour, climate or speed and direction of wind on any given day. Sometimes, cooler air does enter in at lower levels will rise and escape through roof vents or higher-level windows. This process makes natural ventilation more environmentally friendly and inexpensive to run when compared to mechanical ventilation. However, it can leave the workplace vulnerable to certain conditions.
The other type of ventilation used in the laboratory is mechanical ventilation which depends on machine such as air conditioning units. In this type of ventilation, air temperature and quality entering the laboratory can be controlled. Though mechanical ventilation can be controlled more rigorously than natural ventilation, it’s unlikely to remove all contaminants in the air so laboratories may need an additional supply of fresh air, pumped throughout the environment to sustain the safety of the research team. There are two kinds of pressure used which depend on the climate in the laboratories’ surrounding. If the climates are warm and humid, positive pressure mechanical ventilation is used where infiltration may be minimised in order to reduce condensation whereas negative pressure mechanical ventilation is best suited to cold climates where exfiltration must be prevented to minimise condensation.
Despite that, there is a system called hybrid ventilation that involves using mechanical ventilation when the natural ventilation flow rate is too low. It is used in rooms housing patients with airborne infection. In any condition, all of the work which will be carried out in the environment both in short term and in long term should be considered thoroughly when planning a ventilation system for a laboratory.
In conclusion, determining the needs of the laboratory can be ruled out using some or all of these criteria that are the layout and workflow of the facility, temperature and relative humidity, the difference in air pressure between rooms, the number of air changes for each room, air velocity and airflow patterns, the number of particles in the air and cabinetry and other structures which may reduce effectiveness of ventilation. Furthermore, rules and regulations of The Workplace (Health, Safety and Welfare) Regulations 1992 should also be abided to avoid any harm.
Malaysia
