sprinklernotes
Furniture as Partition Obstruction
You have asked the following question: “The owner has installed a desk in many of the units in a hotel. Top of the desk frame is 18.5 in. (or more) down from the ceiling and 8 ft-9 in. from sprinkler. We're protecting these units using extended-coverage sidewall sprinklers (14 ft x 26 ft coverage) in a 24 ft 6 in. room. Are furniture obstructions permitted?” In response to your question, we have reviewed NFPA 13, 2016 edition as the applicable standard. Our informal interpretation is that furniture is not typically viewed as obstructions to discharge. Furniture is temporary and can be moved around. The furniture or desk does appear as a floor-mounted partition but would not create extensive shadowing. Table 8.9.5.2.2 indicates that when a floor-mounted obstruction is located more than 30 in. away, the minimum allowable distance below the deflector is 18-inches, whereas 14.5-in. is provided above the desk. The desk unit would also be limited in width (approx. 5-ft to 6-ft wide) and would not span the entire width of the room. NFPA 13 does recognize that obstructions to sprinkler discharge are difficult to avoid and usually have very little impact on the sprinkler's ability to control a fire. A common example is the fact that sprinklers are not required under obstructions less than 4-ft wide illustrating that the entire floor is not always directly wetted. The primary question is will a fire in the room be controlled? Considering that the sprinkler discharge will not be cleanly cut-off at the corner (like a ray of light) due to the turbulent flow of the water droplets and that the floor area is small, this situation should not have a discernible impact upon activation of the sprinkler or its ability to quickly control a fire. This is of particular value since one of the main objectives of the sprinkler system is to keep the upper layer cool, thus preventing flashover and controlling the fire. In your scenario, the intent of NFPA 13 for providing protection throughout the area is satisfied without covering every square inch of floor area.
