What pipe schedule is acceptable for installation under roads or driveways?

The correct answer, Schedule 40, is deemed acceptable for installation under roads or driveways due to its strength and durability characteristics. Schedule 40 pipe is made from stronger materials that can withstand the increased loads and potential stress encountered in these environments.

In typical applications, including septic systems, the pipe must be capable of bearing the weight of vehicles and resist damage from soil movement or settling over time. Schedule 40 provides a robust option for such installations as it has the right balance of thickness and pressure rating necessary for underground applications.

Other options, while usable in less demanding scenarios, do not offer the same level of structural integrity as Schedule 40. For example, Schedule 20 is too thin for applications where load-bearing capability is crucial, making it unsuitable for placement beneath heavy traffic areas. Schedule 30, while better than Schedule 20, still lacks the necessary robustness required for areas subject to substantial weight. Schedule 60, although it has a thicker wall than Schedule 40, may be over-engineered for most road and driveway applications, potentially leading to unnecessary cost without additional benefit for typical usage scenarios.