This reverse air baghouse expansion joint was made of EPDM operating at above 400F, the EPDM got brittle and ended up adhering itself to the duct and cracking across the bottom - filling the penthouse with SO2 gas. Our team retrofitted the expansion joint with one made of PTFE (Teflon) that could handle the temperature. Reverse air ducts can be hard on equipment because they switch from positive to negative pressure, so you want an expansion joint belt with no excess width in it, or it will get sucked into the duct during pressure changes and wear the edges of the belt out.

This reverse air baghouse expansion joint was made of EPDM operating at above 400F, the EPDM got brittle and ended up adhering itself to the duct and cracking across the bottom – filling the penthouse with SO2 gas. Our team retrofitted the expansion joint with one made of PTFE (Teflon) that could handle the temperature. Reverse air ducts can be hard on equipment because they switch from positive to negative pressure, so you want an expansion joint belt with no excess width in it, or it will get sucked into the duct during pressure changes and wear the edges of the belt out.