How often should vertical support be provided for 1-1/4" or larger gas pipe?

Vertical support for 1-1/4" or larger gas pipe should indeed be provided at every floor level. This requirement is based on the need to ensure the structural integrity and stability of the gas piping system. By providing support at every floor level, you minimize the risk of sagging and potential damage to the pipes, which could lead to dangerous leaks or structural failures.

Moreover, supporting the pipes at every floor level allows for better alignment and easier access for maintenance or repairs. Adhering to this guideline is crucial in maintaining safety standards in plumbing installations, particularly with systems that transport gas.