Article Archive
Risk Assessment
Exterior insulation and finishing system
Volume 24 Number3

As a result of a few recent fires that have started on or involved the exterior of the building, a number of them have been blamed on the use of an exterior insulation and finishing systems (EIFS), a building technique to provide building insulation and architectural ornamentation. While the exact material ignited in the most recent casino fire has not been determined, chances are that a listed EIFS was not the cause of the extensive fire spread. This article will address this issue. EIFS was developed originally to insulate existing buildings without disrupting or losing interior space. The insulating material is installed over the exterior wall of the building, then covered with a finish coat material. EIFS were developed in Europe in the 1940s after World War II, then used in the U.S. and Canada in the 1960s and proliferated in the mid-1970s during the oil embargo.

When EFIS were developed the insulating material was mineral wool; now-a-days expanded polystyrene with a low flame spread is used. Older EIFS used a Portland cement finish coat covering where today's covering can be either polymer based (PB EIFS) or polymer modified (PM EIFS) material. Originally, the system was only installed on masonry units where today it can be installed on drywall, plywood or masonry units. Originally, the assembly was only field installed. Today it can be fabricated and transported to the site in sections. Today, these systems can be used to refurbish existing masonry walls and build exterior walls on low-rise buildings as well as curtain walls on high-rise buildings.

The architects like to use EFIS because architectural features such as columns and decorative attachments can be created rather easily at a low cost. The finish coat can be made to look like poured concrete, concrete blocks, bricks or anything the architect wants. As such, it is difficult to see the difference between concrete blocks, concrete, or EIFS. This is where the problem lies. There are other materials that are fabricated to look like concrete and other non-combustible material when these base materials and coatings are combustible. Polyurethane foam can be shaped and coated to look like these non-combustible materials, but is combustible.

When EIFS were first used here in North America, there was one company making them. Today there are over 25 companies making the components and many other suppliers and certified contractors installing them. Today there are a lot of companies who claim to install an EIFS system, but instead of using fire- tested components, they use polyurethane-coated material or unapproved products. A listed EIFS would be subjected to fire testing in accordance with:

  • National Fire Protection Association (NFPA 285) Standard Fire Test Method for Evaluation of Fire Propagation Characteristics of Exterior Non-Load-Bearing Wall Assemblies Containing Combustible Components (which is the old Uniform Building Code's Standard 26-9; known as the intermediate scale multi-story test).
  • NFPA 268, Standard Test Method for Determining Ignitibility of Exterior Wall Assemblies Using a Radiant Heat Energy Source (which is the old Building Officials and Code Administrators Standard 905).
  • Uniform Building Code Standard 26-4, Method of Test for Evaluation of Flammability Characteristics of Exterior, Nonload-bearing Wall Panel Assemblies Using Foam Plastic Insulation (also know as the full scale multi-story test).

Additionally, the expanded polystyrene insulation must have an ASTM E 84 Standard Test Method for Surface Burning Characteristics of Building Materials flame spread of less than 25.

These requirements come from the ICC Evaluation Services evaluation report number AC 181 acceptance criteria for rigid cellular polyurethane panels used as exterior and interior wall cladding. In a tested and listed system, if the heat were to get to the expanded polystyrene insulation, the polystyrene material would melt (not burn) back to a point where the heat from the fire was below the melting point of polystyrene which is 465?F. Case history has shown that when a fire started in a non-EFIS ornamentation on a building, the fire spread until it reached the listed EIFS and stopped.

The UBC 26-4 fire test is a full-scale test. The set-up consists of a two-story, 24 feet high building with two rooms. Two of the walls are built from concrete block and the floors and ceilings are reinforced concrete. The other two walls have the test sample secured to it. The sample has a four foot by eight foot opening in one wall. A 1,285 pound wood crib is placed three ft from the back wall, centered on the wall. The test is run for 30 minutes. The assembly is considered acceptable if flames do not propagate over the surface of the sample beyond the immediate area of crib flame impingement, flames do not propagate vertically or laterally through the insulation, and flames do not enter the second floor room.

The NFPA 268 test consists of a four foot by eight foot sample mounted on a stand and exposed to a three foot by three foot radiant panel. A heat shield is held between the sample and the radiant panel until the panel is brought up to 12.5 kW/m? (kilowatt of energy per square meter). Once at the testing temperature, the shield is lifted and the test begins. The test lasts for 20 minutes unless there is sustained flaming (ignition) for a period greater than five seconds. If the flaming lasts more than five seconds, the heat shield is brought down and the test is terminated.

So how do you know if you have a concrete, EIFS or some other material for a wall that looks like concrete? It is difficult at best. Ask the building owners. If the facility has the construction drawings and specification, the information would be listed on them. If the building department keeps a record of the construction details, it would be on them.

If the owner does not know and the drawings, specifications and records are unavailable, look for tell-tale signs that it could be an EIFS system. EIFS systems stop short of the ground level to allow the system to drain and prevent deterioration. Look at high trafficked areas such as around doorways to see if there is any damage to the material; if mesh is showing, there is a good chance the system is an EIFS. Once you find out who manufactured the system, check with the company to see if the system is listed or check with Exterior Insulation Manufactures Association (EIMA) to see if they can help. If the material on the wall does not have the finish coat or the mesh, most likely it is a combustible material.

If you have a building under construction and an EIFS is planned, verify the system is tested per the requirements in the ICC Evaluation Services Evaluation Report number AC 181. If the system is field installed, the components and containers should be labeled. If the panels are manufactured in a shop visit the shop to check the material. If work has to be conducted on existing EIFS, the work should be in accordance with the EIMA Guide To Exterior Insulation and Finish System Construction available at http://www.eima.com/technicaltools/eifsconstruction

guidelines. This guide covers plumbing and electrical penetrations and installations.

Part two of this article will address actions to take for non-listed finishing systems as well as tactical considerations during a fire involving non-listed systems.

Peter Willse, P.E., FSFPE is with XL GAPS, a leading loss prevention services provider and a member of the XL Capital group.? "XL Insurance" is the global brand used by member insurers of the XL Capital Ltd (NYSE: XL) group of companies. More information about XL Insurance and its products is available at www.xlinsurance.com. XL Capital Ltd, through its operating subsidiaries, is a leading provider of global insurance and reinsurance coverages to industrial, commercial and professional service firms.

 
 

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