Underground piping, when installed through the outer foundation wall of a building, should be __________.

When underground piping is installed through the outer foundation wall of a building, it is crucial for the piping to be encased in a protective pipe. This practice is essential for several reasons.

First, encasing the piping protects it from physical damage that can occur due to ground movement, settling, or interactions with moisture. These factors can compromise the integrity of the piping and potentially lead to leaks or failures, which can be hazardous, especially when dealing with gas lines.

Second, the encasement helps to prevent corrosion, particularly if the piping is made of metal. A protective barrier can mitigate the effects of soil and moisture that may lead to degradation over time, extending the lifespan of the piping system.

Furthermore, encasing the pipe ensures compliance with the National Fuel Gas Code, which sets forth guidelines for the safe installation and maintenance of gas piping systems. This is critical for ensuring the safety and reliability of gas service to buildings.

While options such as making the pipe of a specific material (like plastic) might be suitable in certain scenarios, building code guidelines emphasize the need for a protective layer when passing through walls. Additionally, leaving the pipe exposed to air or unsupported poses significant risks, as both scenarios can lead to potential damage or safety concerns.