The airtightness of a
high-quality brass copper gas valve can be very good if it is designed and manufactured properly. Brass and copper are both materials that are known for their corrosion resistance and durability, which makes them a popular choice for gas valves.
In order to ensure airtightness, the valve must be designed with tight tolerances and high-quality sealing components such as o-rings or gaskets. The valve should also be tested for leaks and airtightness during the manufacturing process.
It's important to note that proper installation and maintenance of the gas valve can also impact its airtightness. For example, if the valve is installed incorrectly or the seal is damaged during installation, it could result in leaks.
Overall, a high-quality brass copper gas valve can provide excellent airtightness when designed, manufactured, installed, and maintained properly. However, it's always important to follow proper safety protocols and regulations when working with gas appliances to ensure the safety of yourself and others.