Material Selection

Its very difficult to choose the right gasket for the job these days, there are just so many styles. There are many different packings with similar properties and prices. And with the ban on asbestos-based materials, there are many more styles being made to replace them. The four basic things you have to keep in mind when selecting a material are as follows: • Operating Pressure

• Bolt Load

• Resistance to chemical attack (Corrosion)

• Operating temperature

The corrosion resistance can vary based on a couple different factors: • The concentration of the corrosive agent: Higher concentrations dont always mean the fluid will be more corrosive.

• The temperature of the corrosive agent: Higher temperatures tend to speed the effects of corrosion.

• Dew Point: When the fluid moves through the dew point when in the presence of sulfer and water can result in the formation of highly corrosive condensates. The formation of sulfer and water are commonly found in gases resulting from combustion. In critical applications it is common practice to test materials in a lab to determine their chemical resistance to corrosive media under service conditions. In order to design a gasket, an evaluation is required, starting with the type of flange, bolt load, setting stress, etc. Attention to detail is key in this process and every step must be followed in order to get maximum use out of your material. Gasket selection can be simplified by using the Pressure x Temperature Factor.