DuraVent 9244 8DP-FRS 8" Triple Wall Firestop. DuraVent is a leader in the venting industry. DuraVent has a large line up of venting products and continues to design safe and efficient venting part and products. This DuraVent 9244 8DP-FRS 8" Triple Wall Firestop is designed for wood burning fireplaces and stoves. This chimney component was designed specifically for increased protection within the ventilation system.