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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.
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.
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.
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.
October 27, 2008
Effective January 1, 2009, SFRM applied to primed steel surfaces will be required to meet the same criteria required by UL in the United States. The detailed wording contained in the UL Canada Guide Information for Fire Resistance Ratings is reproduced below and may be found in the BXUVC Guide Information section of the Canadian Fire Resistance Directory.
July 9, 2010
In 1991, a study was funded at Underwriters Laboratories to determine if a "Volume Displacement" method of measuring sample volume would lead to more accurate measurement results. UL concluded that the displacement method did result in a more reliable and accurate determination of the density of irregularly shaped objects such as samples of sprayed fireproofing. This document describes how to conduct the "Volumetric Displacement Method" of density measurement.
August 18, 2010
This bulletin provides the reasons why Fire Retardant coatings do not provide hourly fire ratings for steel members. This confusion in the market leads to instances where the wrong Intumescent coating is used to protect steel structural members. It also strongly suggests to the specification writer where in the AIA MASTERSPEC document Fire Resistive and Fire Retardant products should be placed.
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.
Vertical or Inclined Tube Configuration - UL Letter July 24, 2003
Fireproofing applied directly to steel in accordance with appropriate X or Y series UL Design.
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.
Horizontal Tube Configuration - Load Bearing - UL Letter September 25, 2003
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.