Picture the following: an 18" beam 3' off of a wall. On one side of the beam the ceiling is 4" above the bottom of the beam. On the other side nearest the wall, the ceiling is 18" above the beam. The sprinkler heads are located on the ceiling 4" above the beam. No obstructions exist between the beam and the sprinkler head. Are additional sprinkler heads required within the beam pocket on the 18" side? Please provide me your thoughts and NFPA 13 reference sections.
Gary, Are additional heads required to cover the 3 foot area from the wall. I think the answer to your question is a definite PROBABLY.
BUT, If the beam does not create an obstruction to the spray that should cover the 3 foot distance from the wall and under the 18 inch deep beam pocket created by the beam. And if your jurisdiction is willing to grant a modification to the code based on the fact that a condition is allowed in a new edition of the code. Then MAYBE NOT.
A new section has been added to NFPA 13 that allows for the sprinkler to be omitted for a beam pocket if specific requirements are met. The new section is copied below.
nfpa 13 2006 EDITION - 8.8.7 Ceiling Pockets. 8.8.7.1 Sprinklers shall be required in all ceiling pockets. 8.8.7.2 The requirements of 8.8.7.1 shall not apply where all of the following are met: (1) The total volume of the unprotected ceiling pocket does not exceed 1000 ft3 (28.3 m3). (2) The depth of the unprotected pocket does not exceed 36 in. (914 mm). (3) The entire floor under the unprotected ceiling pocket is protected by the sprinklers at the lower ceiling elevation. (4) Each unprotected ceiling pocket is separated from any adjacent unprotected ceiling pocket by a minimum 10 ft (3.05 m) horizontal distance. (5) The unprotected ceiling pocket is constructed of noncombustible or limited combustible construction. (6) Skylights not exceeding 32 ft2 (3 m2) shall be permitted to have a plastic cover. (7) Quick-response sprinklers are utilized throughout the compartment.
Thanks again for your reply. We did not require additional heads in the beam pocket simply because I felt the pocket was adequately covered and of such a limited area that the delayed response from a nearby sprinkler head would not be significant enough to warrant a number of additional heads. Thank you for reminding me of the new beam pocket rules.
