6", 6RV-SC, Storm Collar, Round, Type B Gas Vent. he storm collar provides a seal to prevent water from leaking between flashing and pipe. It is used above the roofline and requires hi-temp silicone sealant on the inner edge. RV series offers round gas vent pipe and fittings for residential, commercial and industrial applications. It features a snap together, non-positional lock system, die formed ends and eliminates the need for all cutting, fitting and special engineering.