It must be recognized by all who perform hydraulic calculations, NFPA 13 does not require a separate or distinct “cushion” to be provided on the sprinkler system’s calculations. (Some people will use the term safety factor, hydraulic buffer or safety margin. Whatever term is used, this refers to a pressure margin below the water supply curve. The remainder of this document will use “cushion” because a safety factor to me implies it should be present.) In fact, NFPA 13 does al