What joint type is prohibited in gas/vacuum systems?

In gas/vacuum systems, the use of certain joint types is restricted to ensure safety and reliability. Among these, it is particularly important to avoid joints that could potentially lead to leaks or failures.

Welded joints can be problematic because, while they provide a strong, permanent connection, any flaws in the weld can become a point of failure. Additionally, if repairs are needed, welded joints can complicate the maintenance process.

Capped joints can also pose issues, as they may not provide a completely secure seal, leading to possible leaks, especially under varying pressure conditions. In systems where the integrity of the gas or vacuum is critical, any point of vulnerability can be problematic.

Flanged joints, while commonly used in various piping systems for their ease of maintenance and reliability, can also be inadequate for gas/vacuum applications if not properly sealed or if the flanges are subject to movement.

The restriction on all these types of joints in gas/vacuum systems is rooted in the need for utmost safety, efficiency, and minimal maintenance complications, reinforcing the decision to prohibit them altogether. Thus, the answer indicating that all of these joint types are prohibited reflects an understanding of these safety principles.