The costs of gasket failure are far greater than the price of the gasket itself. A leaking joint means wasted gas or liquid, and that can have safety and environmental implications. Unplanned downtime cuts into production, reducing output and perhaps needing expensive overtime working to make good the shortfall. Then there’s the actual time and effort involved in opening up the joint, cleaning the faces and installing a new gasket.
Bottom line: you only want to do the job once, so do it right. Here’s what and what not to do.
Don’t reuse an old gasket. It’s a false economy. The material has been compressed and creep has taken place. It won’t have the recovery of a new gasket so it won’t seal as well.
Do clean the mating faces thoroughly. Residual gasket material or adhesives will reduce the ability of the new gasket to make a good seal.
Don’t use a gasket that’s thicker than what the flanges need. Remember, the purpose of the gasket is just to take up surface imperfections and misalignment and to handle expansion and contraction. An unnecessarily thick gasket is more likely to fail.
Do choose a gasket that’s appropriate for the joint TEMP – that’s Temperature, Environment, Media and Pressure. Soft gaskets – those made from materials like neoprene, graphite, fiber or cork – should not be used in high-pressure applications. Ask your gasket material supplier if they can provide pressure-versus-temperature (PxT) charts for your preferred material.
Don’t overtighten a soft gasket joint. Once the gasket has been crushed the material loses its ability to recover as the joint opens up. That leads to leaks.
Do follow the correct bolt tightening procedure. See “How To Bolt Flanges” for details.
Don’t glue thin gaskets together to make one thick enough for the joint. It won’t behave like a gasket of the right thickness and will almost certainly fail prematurely.
Do it right
Replacing a gasket outside of scheduled maintenance periods is often awkward and expensive. Achieving a long life is a function of gasket selection and installation, and these dos and don’ts will help.