What type of repair is not intended for use on pressure vessels?

What type of repair is not intended for use on pressure vessels?

• A. Fillet weld patch
• B. Full encirclement lap band
• C. Non-metallic patch
• D. Cement patch

Answer: (D)

The correct choice is the cement patch. In the context of pressure vessel repairs, a cement patch is not considered an acceptable method due to its inherently weak bonding and limited structural integrity. Cement is not typically capable of withstanding the pressure, temperature, and environmental conditions that a pressure vessel may encounter during operation. In contrast, methods such as fillet weld patches, full encirclement lap bands, and non-metallic patches are recognized in various codes and standards for pressure vessel repair. Fillet weld patches involve welding and provide strong, metallic bonding suitable for load-bearing applications. Full encirclement lap bands involve encircling and securing a section of the vessel with a continuous band, effectively lowering stress concentrations, thus ensuring safety and integrity. Non-metallic patches may also be suitable in certain applications where they are designed specifically for pressure vessels and made from materials that can withstand operational conditions, albeit they must be used with caution. Thus, cement patches lack the necessary attributes to ensure the reliability and safety of a pressure vessel under operational stress, making them unsuitable for such repairs.

The correct choice is the cement patch. In the context of pressure vessel repairs, a cement patch is not considered an acceptable method due to its inherently weak bonding and limited structural integrity. Cement is not typically capable of withstanding the pressure, temperature, and environmental conditions that a pressure vessel may encounter during operation.

In contrast, methods such as fillet weld patches, full encirclement lap bands, and non-metallic patches are recognized in various codes and standards for pressure vessel repair. Fillet weld patches involve welding and provide strong, metallic bonding suitable for load-bearing applications. Full encirclement lap bands involve encircling and securing a section of the vessel with a continuous band, effectively lowering stress concentrations, thus ensuring safety and integrity. Non-metallic patches may also be suitable in certain applications where they are designed specifically for pressure vessels and made from materials that can withstand operational conditions, albeit they must be used with caution.

Thus, cement patches lack the necessary attributes to ensure the reliability and safety of a pressure vessel under operational stress, making them unsuitable for such repairs.