Firestopping Book Firestopping Book | Page 169

CHAPTER 6 Additional Attributes of Firestop & Miscellaneous Topics Apart from what we have covered in the previous chapters of this book, there are few other important details regarding Firestop systems which can be of great advantage for any architect, designer, building owner & inspectors. Let’s look at these important topics one by one: SMOKE LEAKAGE RATING It has been seen that smoke inhalation is one of the most common causes of fire incident injuries. According to the National Fire Protection Association (NFPA), most fire deaths are the result of smoke inhalation rather than burns. Why is it so difficult for people to escape a fire? One of the many reasons given for this is that smoke may be so thick and dense that occupants get disoriented. For a fire to occur fire needs oxygen and consumes much of the available oxygen individuals need to breathe and remain conscious. This can happen so quickly that occupants are overcome and unable to reach easily accessible exits. NFPA’s chart below illustrates what occurs to a person at various oxygen levels. Notice that once oxygen levels drop to half the normal amount, the movement toward exits becomes difficult or impossible: 169