Where are unprotected gas lines not allowed?

Unprotected gas lines are not allowed above the ceiling because this space can pose significant safety risks. In the event of a gas leak, which can occur due to various reasons such as corrosion or physical damage to the pipes, the gas would accumulate in an enclosed area, making it extremely hazardous. Above ceilings, where ventilation may be limited, gas can build up without proper detection or escape routes, potentially leading to dangerous situations such as explosions or health hazards from inhalation.

In contrast, gas lines are often run in basements and crawl spaces where there is typically better access for inspections and maintenance. Even if unprotected gas lines are allowed in these areas, they must be installed with consideration for potential hazards and in accordance with local building codes and regulations.