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Is it obstruction or not (NFPA 13-2016, paragraph;

Question asked by lucky on Apr 27, 2017
Latest reply on May 4, 2017 by ihumberson

Hello everyone! 


First of all - sorry for my english, i am from Russia and writing with dictionary.


I am an engineer of technical supervision, and participate in the construction of a hypermarket where

fire protection system shall be in accordance with NFPA13.


of course, this technical document is quite new to me and i ask for a help.




There is an area of the hypermarket  with girder covering, distance between beams is 4,0 meters;

Also between beams there are two branches of fire protection system (distance between branches is ~2,0 meters)

Distance from the roof deck to sprinkler head is about 400mm...


paragraph says that under obstructed constraction, the sprinkler deflector shall be located in accordance with ONE of the following arrangements:


2. installed with the deflectors at or above the bottom of the structural member to a maximum of 550mm below the ceiling\roof deck where the sprinkler is installed in conformance with sprinklers shall be arranged to comlpy with ONE of the following arrangements:

(1) subsection , table and fig. shall be followed Continuous or noncontinuous obstructions less than or equal to 18 in. (457 mm) below the sprinkler deflector that prevent the pattern from fully developing shall comply with



But inspector of the insurance company says that these beams are not the obstruction for sprinklers: because there is another sprinkler in other side of each beam and distance between them less than 1/2 of the maximum distance (3,1 meters)


But we purposely mount them at distance 400mm to respect declared pattern for that sprinkler (TY7151)..


Is inpector right?