Which components should be replaced before replacing a manway cover?

Replacing a manway cover involves several important steps, and ensuring a proper seal is critical for system integrity. The correct answer relates to the gasket used in the replacement process.

When you replace a manway cover, using a new gasket that is the same thickness as the old one ensures that the fit and seal maintain the equipment's design specifications. This is crucial because a gasket that is too thick or too thin can compromise the seal, potentially leading to leaks or failures under pressure.

Gaskets are designed to fill in imperfections and create a tight seal between the manway cover and the tank or vessel. If a thicker gasket is used, it might not compress adequately when the cover is tightened down, which could prevent a proper seal and lead to issues like leaks. Conversely, if a thinner gasket is chosen, it may not fill the gap effectively and could also lead to failure.

Therefore, utilizing a gasket that matches the original thickness preserves the intended sealing capabilities of the system, ensuring safety and efficiency in operation.