Breather Valves are one type of safety valves. This type of valve is intended
for fuel oil storage installations.
As the name suggests, the valve is expected to breathe so that the pressure inside the storage tank can be maintained so as not too vacuum or pressured due to pumping fluid in and out and evaporation due to ambient temperature.
There are many Breather Valve Manufacturers available in the market. however, you must check whether the company and the manufacturing process are in accordance with applicable standards.
Some of these manufacturers are Shand & Jurs, Protectoseal and KSPC.