NFCA Technical Information
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March 7, 2008
According to the International Building Code (IBC), 2006, “Fire resistance rated assemblies tested in accordance with ASTM E119/UL 263 shall be considered unrestrained unless evidence satisfactory to the authority having jurisdiction is furnished by a registered design professional showing that the construction qualifies for a restrained classification.”
When the design professional has determined that the structure to be fireproofed is in a restrained condition, knowledge of the Building Code and the UL Fire Resistance Directory are vital in selecting the proper SFRM thickness. The information in this Bulletin is provided to guide in the appropriate use of the UL Designs and SFRM thickness determination.
Guidance Information Bulletin No. 1001
March 7, 2008
Painted/primed structural steel and decking often trigger requirements for bond testing and the use of metal lath. There are three critical issues with painted steel substrates:
A. Ambient bond - the ability of fireproofing to remain in place during normal use for the design life of the structure.
B. Performance of the paint or primer during exposure to fire.
C. Sensitivity of the paint to alkali exposure associated with Portland cement based products.
Requirements to ensure compatibility of the paint with the fireproofing are dependent on the substrate in question and are detailed in this Bulletin.
Guidance Information Bulletin No. 1002
March 7, 2008
UL has clarified several allowable options available for treatment of the cavity areas formed above the flanges of beams where they pass under 100% fluted metal decking. The flute fill options depend on whether the beams run perpendicular or parallel to the flutes of the metal decking, and for the former, whether the top flange of the beams is less than or greater than 8 inches wide. The options are identified in this Bulletin.
Guidance Information Bulletin No. 1003
March 7, 2008
The UL Fire Resistance Directory allows for the adjustment of thickness of SFRM for Restrained and Unrestrained beams when alternate sized steel beams are substituted for the given beam size in the A700, A800, A900, D700, D800, D900, G700, J700, J800, J900, N700, N800, P700, P800, P900, S700 and S800 series designs, provided the beams are of the same shape and the thickness of SFRM is adjusted in accordance with the following equation:
T1 = ((W2/D2 + 0.6) x T2) / (W1/D1 + 0.6)
This equation is limited to adjustment where the beam is classified as compact. It is not to be used where the steel section is classified as non compact. See details in this Bulletin.
Guidance Information Bulletin No. 1004
November 21, 2003
UL has established the SFRM fireproofing thickness required to protect hollow steel tubes.
This position covers hollow structural steel tubes used in a vertical or inclined position, tubes used in
non-load bearing and load bearing horizontal positions.
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Fireproofing applied directly to steel in accordance with appropriate X or Y series UL Design.
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Horizontal Tube Configuration - NON-Load Bearing - UL Letter February 28, 2000
Horizontal tubes cannot carry any load besides their own weight.
Mechanically attach metal lath on all exposed sides of the tube spaced 12 inch on center in each direction. Fireproofing applied to lath in accordance with appropriate X or Y series UL Design.
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There is no fire teat data on the structural performance (deflection under load) of load
bearing hollow steel tubing during exposure to fire. Therefore, the use of the column design
thickness cannot be used in this application. This will require large-scale fire testing in order
to generate proper fire ratings. The industry recommends using firesafing thickness applied to
mechanically attached lath on load bearing horizontal tubes. Firesafing thickness is designed to
limit the maximum temperature increase to 250 degree F and the individual temperature increase to 325
degree F above ambient temperature. This is not a rating but limits the temperature of the steel
during exposure conditions. This industry recommendation is intended to provide assistance to the architect, building owner and the
Authority Having Jurisdiction (AHJ).
August 1, 2003
UL has just issued an article tilted “The
Significance of The UL Classification Mark on Intumescent Coatings”. This article describes
the importance of proper testing protocol for intumescent coatings under fire conditions and product
exposure performance testing, classifying coatings as interior grade and exterior grade.
The UL Classification Mark indicates that both types of testing have occurred and that the
material was manufactured under UL’s Follow-UP Services Program.
The article also discusses the importance of Intumescent coating thickness on fire test
performance and how the coating works under fire test conditions. UL also points out that
the general equations relating fire protective thickness to the size and mass of a steel section for
sprayed fire-resistive materials do not apply to intumescent coatings.
August 1, 2003
For many years open web steel joists were manufactured with round bottom chords. During that time many UL
Fire Rated designs were promulgated with fire protection based on test of round chords. The steel industry then
changed their manufacturing by using angled bottom chords as a replacement for round bottom chords. In a letter
dated October 7, 1993, UL concluded through computer simulation analysis that there was not a significant
difference in the performance of steel joists when round bottom chords are used in angled bottom chords in
joists of comparable depth and weight per linear foot. This evaluation allowed the use of spray applied
fireproofing thickness tested on round bottom chords for joist members with angled bottom chords.
The attached UL letter dated July 8, 2003 reverses the conclusion discussed above. UL now determines
that that for designs that specify the use of round bars as bottom chords of joists, the minimum thickness of
fireproofing is applicable only to round bars of equal or greater area of steel. This means that a thickness listed
for round bottom chords is no longer applicable to joists with angles as bottom chords. Designs that may be affected by this ruling either explicitly state round bottom chords in the text of the design listing or show round bottom chords in the design drawing.
UL is updating the front of the UL Fire Resistance Directory Volume I, Section III, item 7 - Steel Joists and a
revision to the UL Online Certification web site under the BXUV Guide Information will be made.
You should check with your fireproofing supplier to determine the status of any UL design that currently states
round bottom chords in the text of the design listing or shows round bottom chords in the design drawing. |
