Sep 25, 2010

CASE STUDY: 1-hour Fire-Rated separation provided by Paint

The ASTM E 119 (Standard Test Method for Fire Tests of Building Construction and Materials) is a test standard that various construction assemblies must meet to be considered fire-resistive. As required by the 2003 International Residential Code, the 1-hour fire-rated wall between dwelling units in a two-family home must meet this ASTM E 119 standard. This is a change from the last building code. Before September 2007, our jurisdiction followed the Uniform Building Code 1997, which as amended by Honolulu County, did not require any fire-rated separation between units in a two-family dwelling.

A wall assembly that has been tested and approved as meeting the ASTM E 119 standard, describes such things as the type of screw used to secure the gypsum board to the wall, spacing of the screws, alignment of the gypsum board (ie. stagger joints). There are different ways of achieving the same fire-resistance rating, using the same or different materials or combination of materials.

The main difference between wall assemblies and coatings (ie. paint) is that in and of itself, paint is typically not tested as an assembly because it really depends on what the paint is applied to. However, its other properties like ability to resist the spread of fire or transfer thermal heat can be measured. Those properties can improve survivability in a fire. It would be possible to apply the Intumescent Coating to a specific type of wall assembly and test it to ASTM E 119 standards, however, the general appeal of an Intumescent Coating is that you can apply it on various types of existing construction and assemblies that do NOT meet the typical standard.
When converting a portion of an existing home into an attached Ohana Dwelling or attached Accessory Dwelling Unit, an ASTM E 119 approved 1-hour fire-rated wall is required between the main house and the 2nd unit. This is a life-safety requirement.

For older single-wall homes in Hawaii (LEFT - image from State of Hawaii DCCA, Loss Mitigation Grant Program 2007), this often requires costly retrofits to construct a new 2x4 stud wall with 5/8" type "X" gyp bd on both sides. All structural members supporting the wall must also be provided 1-hour fire-rated protection.

In Honolulu, per our prelim discussions with the Department of Planning and Permitting, an Intumescent Coating is an accepted substitute in lieu of the stud wall. This can create an enormous amount of savings and time, as the intumescent coating, applied as per manufacturer's recommendations, can substitute for a new stud wall and 5/8: type x gypsum board.

BELOW: Video from FireFree Coatings, Inc., an Intumescent Paint manufacturer.