Car parks are known to be high-risk areas for CO (carbon monoxide) accumulation due to the exhaust emissions of vehicles. In order to ensure the safety of occupants and comply with building codes and standards, it is necessary to implement effective ventilation systems that remove CO from the air. Computational Fluid Dynamics (CFD) analysis is a powerful tool that can be used to optimise the design of such ventilation systems.
In Australia, the National Construction Code (NCC) mandates that car park ventilation systems be designed to maintain a CO concentration of less than 50 ppm (parts per million) during normal operating conditions, and less than 100 ppm during a fire emergency. AS1668.2 provides guidelines for the design and installation of mechanical ventilation systems for car parks.
To conduct a CFD analysis of a car park ventilation system, a 3D model of the car park must first be created in CAD software. This model should include all relevant features such as ramps, columns, and ventilation openings. The CO generation rate should be calculated based on the P factor specified in AS1668.2, which represents the expected percentage of maximum parking capacity occupied by motor vehicles generating exhaust emissions.
The ventilation system, typically consisting of jet fans, should also be modelled in the 3D environment. The size, number, and placement of the jet fans will depend on the specific requirements of the car park and must be designed to achieve the required CO concentration levels.
The CFD analysis should simulate various scenarios such as different levels of CO generation, varying ventilation rates, and emergency situations such as a fire. The analysis results can then be used to optimise the ventilation system design, including the number and placement of jet fans, and to ensure compliance with building codes and standards.
In conclusion, CFD analysis is an important tool for designing effective car park ventilation systems for CO removal. This analysis allows designers and engineers to optimise the system's design and ensure compliance with the relevant codes and standards. This ultimately leads to safer and healthier environments for car park occupants.