Air valves are usually installed in underground chambers, with sectioning devices to allow maintenance and venting pipes to ensure the proper air circulation. Unfortunately, if drainage systems are not part of the design, the air valves may be submerged in case of flood. In such cases, the air valve would open because of negative pressure, and all the water inside the installation chamber could enter the main pipeline. This can be a cause of pollution for the entire distribution network.
CSA provides a solution to this problem through a variation in the current combination air valves for water application by using a watertight exhaust system that can be connected to a pipe leading to a part of the installation not exposed to flood. This protects the pipeline against negative pressure and helps meet standards for potable water.