{{unreferenced, date=August 2009
Pneumatic non-return valves are used where a normal
non-return valve would be ineffective. This is for example where there is a risk of
flood water
A flood is an overflow of water ( or rarely other fluids) that submerges land that is usually dry. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Floods are an area of study of the discipline hydrolog ...
entering a site but an equal risk of pollution or a
chemical spills A chemical accident is the unintentional release of one or more chemical hazard substances which could harm human health and the environment. Such events include fires, explosions, leakages or release of toxic or hazardous materials that can cause ...
leaving a site and polluting the environment.
Pneumatic non-return valves are installed below ground and can be used to pneumatically lock the non-return valve closed thus containing a site in the event of a spill.
It is common practice to lock sites using pneumatic non-return valves during the loading or transferring of chemicals or hazardous waste. Pneumatic non-return valves have a longer service life when compared to
pneumatic bladder systems.
Valves
Environmental protection