Introduction
Ventilation systems in construction are essential to ensure safety and thermal comfort of workers during construction works. Poor ventilation in construction sites can cause a number of health problems as well as reducing productivity. Ventilation during construction works is required to prevent pollutants, fumes, and hazardous gases from accumulating inside the confined spaces.
Regulations and Standards
In the United States, local legislation, such as the United States Occupational Safety and Health Administration (OSHA) and other national regulations, set standards for air quality and ventilation. Additionally, the World Health Organization (WHO) provides guidance for indoor air quality standards. The maximum levels of ambient air concentrations for most pollutants must not exceed the recommended exposure levels set by the WHO.
Methods
Ventilation systems vary from one site to another. Factors that affect the design of the ventilation system include the type of construction, size of area and the type of materials used.
General ventilation works to reduce the concentration of hazardous pollutants. This is usually achieved by either natural ventilation or mechanical ventilation. Natural ventilation is a passive approach that uses the pressure difference of everyday wind patterns to cause an airflow to move through an area. A mechanical ventilation system uses powered fans, air conditioning, and air scrubbers to circulate air and keep concentrations of hazardous gases low.
Local Exhaust Ventilation (LEV) is another form of ventilation which works to reduce exposure to dust and other pollutants at the source. This is usually achieved by capturing hazardous pollutants at their release point with an extraction hood. Mechanical LEV systems often use a combination of supply and exhaust fans, vents and ducts, to capture hazardous pollutant and draw them away from the environment and towards the extraction hood.
In addition to ventilation systems, personal protective equipment (PPE) such as face masks and breathing apparatus can also be used to protect workers from airborne pollutants.
Conclusion
Ventilation in construction sites is essential for the health and safety of workers, as well as for thermal comfort. Regulations, standards, and guidance set by OSHA, WHO, and other regulating bodies exist to ensure air is safe and comfortable. Methods such as general ventilation, local exhaust ventilation and personal protective equipment should all be implemented to ensure air quality standards are met.
