Risk Assessment - Exterior insulation and finishing
Article originally published in the July-August 2009 issue of Industrial Fire World. Reposted in the wake of the Grenfell Towers disaster in London. To read part one of the series, CLICK HERE. The first part of my article I went over some of the fires the systems were involved in, how the systems are fabricated, and the fire tests conducted on the systems. As discussed in previous articles, these systems may be used when industrial buildings need to blend in to the local community or when an attractive exterior is desired for freestanding office buildings at large industrial plants.
I would like to make an update in that article. I spoke with an investigator who visited the casino fire, who said that while the exact cause has not been determined, workers were welding a cat walk on the roof side of a parapet when the fire broke out in what appears to be a non EIFS decoration. The fire did spread a bit in what appears to be an EIFS system and stopped at a stucco-covered component. The type of system and whether it was listed or tested has not been determined. Built between 1994 and 1995, the building used the 1991 edition of the Uniform Building Code.
In this part of my article, I will go over some of the pit-falls, such as what precautions should be taken and how to plan for response. The International Building Code (IBC) has requirements that either the assembly is tested using a large-scale test based on the actual end-use configuration or that each component of the system has prescribed requirements. The tests used are National Fire Protection Association’s NFPA 285 (the same as UBC Standard 26-9) intermediate scale multi-story test, NFPA 268 (the same as Building Officials and Code Administrators Standard 905) radiant panel test; and UBC 26-4 (the predecessor to UBC 26-4 was UBC 17-6, developed in mid 1980’s) full scale multi-story test.
Unfortunately, these tests do not represent some of the “end-use” configurations of the EIFS systems. These tests allow the heat from the fire to dissipate because there are no overhangs where the heat can collect and build-up. In addition, the panels are typically tested with 4 inches (100 mm) of EPS insulation. A pit-fall is that designers will specify the installation of EIFS on walls under overhangs, a condition that will allow the heat from a fire to collect and cause the system to flash. They also design ornamentation that can be a lot thicker than 4 inches (100 mm).
Tests that would simulate the overhang condition are the ones conducted on interior wall assemblies, UL 1040, Standard for Fire Test of Insulated Wall Construction, FM 4880, Approval Standard for Class 1 Insulated Wall or Wall and Roof/Ceiling Panels; Plastic Interior Finish Materials; Plastic Exterior Building Panels; Wall/Ceiling Coating Systems; Interior or Exterior Finish Systems, and NFPA 286, Standard Methods of Fire Tests for Evaluating Contribution of Wall and Ceiling Interior Finish to Room Fire Growth.
These tests would allow the heat from the fire to build-up as if it were an overhang. The NFPA 286 test set-up is a room that measures 8 ft 2 in. (2.44 m) wide by 12 ft 2 in. (3.66 m) wide by 8 ft 2 in. (2.44 m) high with the material being tested on the two walls next to the ignition source and the ceiling. The ignition source is a gas burner that produces a net heat output of 40 kW ± 1 kW for the first 5 minutes, followed by a net heat output of 160 kW ± 5 kW for the next 10 minutes. In my research I found one product that was tested to FM 4880. The system was tested by FM for unlimited height but a few years ago FM stopped listing all EIFS. The manufacturers specifications state the FM approved products and configurations must be specified.
Another pit-fall is the requirements in the International Code Council’s (ICC) Evaluation Services’ Acceptance Criteria For Rigid Cellular Polyurethane Panels used As Exterior And Interior Wall Cladding AC181. Part 3 of the acceptance criteria requires durability tests including accelerated weathering, freeze-thaw, salt spray resistance, water resistance; fire, ignition, structural performance, tensile bond strength, flexural strength, and water penetration. However, the parts containing the fire testing for use on non-combustible and fire resistive construction are optional for the listing. They are:
1 – Part 3.2.2 (1) the potential heat of the panel not exceed 6,000 Btu/ft² (68.2MJ/m²) from NFPA 285,
2 – Part 3.2.2 (2) the requirement the panel, coating, and weather resistant barrier be tested separately, each to have a smoke development of 25 or less per ASTM E 84 (the panel still must have a flame spread of 75 or less per 3.1.2),
3 – Part 3.2.2 (3) the wall assembly is tested and complies with the conditions of acceptance of UBC Standard 26-4 or 26-9, or NFPA 285.
4 – Part 3.2.3 panels for use in fire-resistive construction require testing in accordance with ASTM E 119.
Part 3.2.4 is also confusing. It states, “For recognition under the International Building Code, on other than exterior walls of Type V construction, the panels must be tested in accordance with NFPA 268.” Does this mean only interior wall of Type V construction need to be tested? Or exterior walls of all other construction types? The correct answer is the exterior walls of Type I, II, III, and IV construction.The reviewer might not notice the fact the system was not tested for these conditions. When reviewing the specifications and it states it was tested per AC 181, check the report to see if these optional tests were conducted.
Additional pit-falls include not having the firebreaks between floors properly installed and using non-labeled insulation boards. Although the systems are tested and the panel should have firebreaks, if they are misaligned, or with any curtain wall, the joint between floor and wall not properly made, the fire could spread vertically. The IBC requires the insulation on all systems be labeled on either the face or edge of each board. The label must contain the manufacturer’s or distributor’s identification, model number, serial number or definitive information describing the product or materials’ performance characteristics and approved agency’s identification.
The hardest part is knowing who’s system has been installed since there is no way of labeling the finished system. Ask the building owner which manufacturer made the components, who installed the system, and who signed off on it.
What precautions must be taken? Inspect the system periodically for cracks, chips, or wear. If the finish coat is worn away, cracked, or chipped, the heat from a small fire could get the insulation involved. If the system has not been fire tested, keep equipment such as transformers, trash compactors, trash bins, idle pallet storage or anything that can produce heat away from the wall. If the system is installed under an overhang, provide exterior sprinklers in the overhang to help protect the system.
If the system was installed over a masonry wall because of cracking of the wall, check to see if the cracks in the interior of the building have been filled in with mortar to prevent a fire from inside the building igniting the insulation material. If there is an EIFS system under an overhang, do not stage anywhere near there. It can become involved. Do not use a straight stream under high pressure on these walls, as it could crack the finish coat and expose the insulation.
The biggest precaution you can take is to recognize that the system is there and pre-plan if there is a chance for it to become involved with a fire. Remember this material is not fire resistive. (To read part one of the series, CLICK HERE.) 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, insurance companies and other enterprises on a worldwide basis. More information about XL Capital Ltd is available at www.xlcapital.com.