For gas piping with fuel gas heavier than air, what is the venting requirement when installed in vertical chases?

When dealing with gas piping that carries fuels heavier than air, it is critical to ensure proper venting to avoid the accumulation of gas in enclosed spaces. Gas that is denser than air will settle in lower areas, making proper venting essential for safety.

Venting to the outdoors is the correct approach because it ensures that any gas that might leak from the piping is safely dispersed outside, away from inhabited or enclosed spaces. This prevents the risk of an explosion or harmful exposure to gas, which could occur if the gas were allowed to accumulate within the structure.

Venting only to the chase would not adequately protect against potential gas build-up since the chase could create a confined space where gas could accumulate. Similarly, venting to the indoors would pose a serious safety hazard by allowing heavier-than-air gas to collect inside a building. Venting to both the chase and outdoors could lead to confusion about the need for gas to escape properly.

Therefore, venting to the outdoors is the safest and most effective method to mitigate the risks associated with gas piping that carries heavier-than-air fuels.