Masonite Board Rating

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Author Message Ruppert Rangel, AIA CCS Senior Member Username: rangel Post Number: 19 Registered: 08-2006 Posted on Monday, October 13, 2008 - 06:28 pm:    We are trying to use masonite board in a children's area of a hospital. The idea is to use 1/4 inch thick masonite on tight radius, curved ceiling furring edges, probably too tight for thin gypsum board. I have tried to determine what flame spread rating masonite has without success. It needs to be Class B. Has anyone come across any pertinent rating information? Richard Baxter, AIA, CSI Senior Member Username: rbaxter Post Number: 81 Registered: 12-2004 Posted on Monday, October 13, 2008 - 06:45 pm:    I recently discovered that the product that most of us know as ‘masonite’ is actually “Duron”, which is the current name that Masonite gives to its hardboard product. The generic industry name for it is “hardboard”. I found the following website which classifies it as class III or C: http://www.dps.state.la.us/sfm/doc_flamespread.html. Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP Senior Member Username: specman Post Number: 694 Registered: 03-2003 Posted on Monday, October 13, 2008 - 07:22 pm:    According to the link below, which is a document from the AFPA, hardboard has a flame spread index between 148 and 166 depending on the type of facing. This places it in Class C. In order to be Class B, the flame spread index needs to be 25 to 75. According to the document, all the products listed have a smoke developed index of 450 or less, which is also required in order to achieve any of the three classification categories. Flame Spread Performance of Wood Products Wayne Yancey Senior Member Username: wayne_yancey Post Number: 119 Registered: 01-2008 Posted on Monday, October 13, 2008 - 07:46 pm:    Ronald, Can an opaque intumescent finish be applied similar to intumescent transparent finishes for wood standing and running trims and panelling to bring the flame spread to Class B? Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP Senior Member Username: specman Post Number: 695 Registered: 03-2003 Posted on Monday, October 13, 2008 - 08:01 pm:    I believe it is possible depending on the attachment of the board and the willingness of the building official to accept an alternative method and material. The attachment would likely need to comply with Section 803.4. The application of an intumescent paint would then have to be approved by the building official, since there is no prescriptive provision in the IBC. Jerome J. Lazar, RA, CCS, CSI, SCIP Senior Member Username: lazarcitec Post Number: 595 Registered: 05-2003 Posted on Tuesday, October 14, 2008 - 12:29 am:    We have had success using a product manuf by Flame Control Coatings, LLC over wood doors to a/c closets, the following product is Class A, however Class B may be available on web site: Flame Control No. 20-20A is a latex water based intumescent fire retardant paint, manufactured in accordance with Federal Specification TT-P-001932. This product is designed for use on interior surfaces where it is either necessary or desirous to reduce the surface burning characteristics of the substrate. ULC /ULI Listed. http://www.flamecontrol.com/d_paints_n.html Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP Senior Member Username: specman Post Number: 696 Registered: 03-2003 Posted on Tuesday, October 14, 2008 - 01:05 am:    Jerome, it appears that the Flame Control Coatings paint is used as the final coat, which means the entire surface (compliant and noncompliant surfaces) will likely need to be painted to ensure consistent color and sheen. On the ICC-ES website, they have an evaluation service report (ESR-1838) for No Burn fire-retardant coatings with a Class A rating. According to the ESR, the coating can then be painted over with up to 7 coats of latex paint. Therefore, you only need to treat the area of concern with the special coating. There's another ESR for another fire-retardant coating, but it is a final coat and cannot be painted over. Although not a guarantee, having an ESR will will help with product approval by the building official.