The Von Duprin 1609 cannot be used on a pair of fire rated doors. We recommend using the Von Duprin fire rated mortise exit device in lieu of the rim device such as the Von Duprin 5575-F,...
There are two main differences:The bottom latches are differentThe Von Duprin 98/9947 concealed vertical rod device covers up to 1/4" undercutThe Von Duprin 98/9948 concealed vertical rod device co...