| NFPA 13 TIA Limits ESFR Installation Under Obstructed Construction |
| A Tentative Interim Amendment
has been issued to the 1999 edition of NFPA 13 to clarify the use of ESFR
sprinklers under ceilings with beams and joists. The TIA revises
Section 5-4.6.3 in its entirety, deleting the current three subsections
that respectively address smooth ceilings and open trusses, beamed ceilings,
and paneled ceilings. The new wording of Section 5-4.6.3 is as follows:
"5-4.6.3 ESFR sprinklers shall be permitted for use in buildings with unobstructed or obstructed construction. Where depths of the solid structural members (beams, stems, etc.) exceed 12 in., ESFR sprinklers shall be installed in each channel formed by the solid structural members. Minimum sprinkler spacing and area of coverage shall comply with sections 5-11.3.4 and 5-11.2.3." To explain the requirement, a second paragraph has been added to appendix section A-5-4.6.3 as follows: "A-5-4.6.3 ESFR sprinklers are not suitable for all types of building construction. Various ceiling construction features such as those with deep narrow ceiling channels can cause unacceptable delays with sprinkler activation and obstruct the sprinkler's discharge pattern. Where sprinklers are installed in each channel of obstructed construction there needs to be adequate separation between sprinklers as identified in Section 5-11. The limitations of sections 5-11.3.4 and 5-11.2.3 will preclude the use of ESFR sprinklers under narrow deep channels." Also per the TIA, a new definition of concrete tee construction has been added to Section A-1-4.6 of the appendix, which provides examples of obstructed construction. This takes the form of a new subsection: "(c )Concrete Tee Construction. The term "concrete tee construction" as it is used in this standard refers to solid concrete members with stems (legs) having a nominal thickness less than the nominal height. See Figure A-1.4.6(b) for examples of concrete tee construction." The TIA was sponsored by the Minnesota Office of the State Fire Marshal and was issued by the NFPA Standards Council with an effective date of August 9, 2000. The TIA is intended to clarify that ESFR sprinklers are not permitted under deep beams, since there is no test data that supports their use under such conditions. The reference to Section 5-11.2.3 (minimum area of coverage) and Section 5-11.3.4 (minimum distance between sprinklers) clarify that it is not acceptable to violate these minimums when placing ESFR sprinklers in every beam pocket.
|