Heating, sterilization, humidification and power generation are a few of the ways steam is used in industry and commerce. Steam systems combine heat with pressure so any leak in pipework is potentially dangerous. This is especially true when using steam that’s superheated, and therefore not visible to the naked eye. To reduce the risk of leaks, material for steam system gaskets should always be selected with regard to the specific requirements of the equipment being worked on.
Steam Gasket Requirements
Steam is water vapor at or above 212°F (100°C). In steam systems, it’s under pressure and usually at higher temperatures. The temperatures and pressures used vary by system and these need determining before selecting a steam gasket.
Superheated steam is steam at temperatures above the saturated steam curve for that particular pressure. Temperatures of 500°F (260°C) or more are possible, creating special requirements for gasket materials. Here we’ll address materials suitable for gaskets in conventional saturated steam systems.
Steam Gasket Material
Many common gasket materials don’t handle steam well. Neoprene and silicone are two examples. Nitrile rubber or NBR is another material seldom recommended, mainly because depending on formulation its upper temperature limit is around 300°F (150°C)
One good steam gasket material choice is Ethylene Propylene Rubber (EPDM.) EPDM gaskets will handle steam at temperatures up to 395°F (200°C) and also provide good resistance to dilute acids and alkalies, alcohol, ketones and automotive brake fluids.
Styrene-butadiene rubber (SBR) gaskets are another good choice. While lacking the upper temperature limit of EPDM – 340°F (170°C) is about their limit – they do hold up well to steam. Particularly in cloth-inserted grades SBR gaskets resist both pressure and high compression loads.
Select for the Specific Application
Steam systems can be difficult to gasket because temperatures and pressures vary between systems. When seeking material for steam system gaskets always determine the properties of the system to be sealed. Don’t use a gasket purchased for one system in another that may have different characteristics. As always, material specialists at Hennig are available to answer any questions. Contact us today.
