Academy instructors Manly Molton and Marc Lucero demonstrate the 7-9-8 coffin cut. It is of one methods we teach our FF’s for venting a commercial flat roof with conventional construction. Using this cut allows the vent team to expand the hole quickly with only two additional cuts. Note after making the head cut and knockout cut, the right leg cut (vertical cut) is left twice as long as the head cut. This allows the hole to be expanded after the nine cut (bottom cut) is completed and the hole has been opened and cleared. Once this is done all that is needed is to lengthen the left leg cut and and additonal bottom cut ( the 8 cut ). for those that are unfamilar with the name it comes from the three steps it take to make this hole. Starting with the #7 the #9 expanding it to the # 8. The cut originated in the NYFD.
Text and video from Marc Lucero on YOUTUBE