DuPont presented results of an extensive study on clean agent fire suppression of energized electrical equipment (Class C) fires at the Suppression and Detection Research and Applications Conference (SUPDET 2007) in Orlando, Fla., last week. The goal of the study was to review both past and recent testing related to Class C fires and to examine the implications of these studies with respect to the minimum design concentration of clean agent necessary to extinguish Class C fires. The entire presentation is available for download (43-pg .pdf).
The Current Issue: Comment ROC 2001-61a proposes changes to the minimum Class C design concentration requirements of clean agents as specified in NFPA Standard 2001. ROC 2001-61a recommends increasing the minimum design concentration for all clean agents by 33 percent (1.6 times the Class A minimum extinguishing concentration) for Class C fires. This action is expected to increase system costs by at least 33 percent.
If ROC 2001-61a is accepted, it will become the industry standard. A Notice of Intent to Make a Motion (NITMAM) has been filed to reject ROC 2001-61a, which will result in a floor vote on the comment at the National Fire Protection Association (NFPA) meeting held during the NFPA World Safety Congress in Boston, Mass., June 3 - 7, 2007.
The DuPont Perspective: DuPont believes that comment ROC 2001-61a should not be adopted. The redundancy that it would require would result in unnecessary cost to industry and consumers while providing no meaningful improvement to safety. The current minimum Class C design concentration levels defined in NFPA Standard 2001 are sufficient and the revisions outlined in ROC 2001-61a are not justified by field experience or by the cited studies on which ROC 2001-61a was based. Mark L. Robin, Ph.D., DuPont Fluoroproducts, and Bon Shaw and Brad Stilwell of Fike Corporation reviewed in detail the fire testing on which ROC 2001-61a was based, and described the results of additional fire testing that challenges the proposed mandate to increase the minimum design concentrations for Class C Fires. Details were outlined in their presentation, “Development of a Standard Procedure for the Evaluation of the Performance of Clean Agents in the Suppression of Class C Fires.”
The DuPont study yielded three key conclusions:
- Field results do not justify ROC 2001-61a. There is not a single documented example of a clean agent system failing to extinguish a Class C fire over the 15 year period during which clean agent systems have been installed;
- The cited studies do not justify ROC 2001-61a. With one exception, the cited studies are flawed in both their use of materials and in the test conditions employed, and several of the cited studies are characterized by poor reproducibility. With one exception, the cited studies did not employ materials or conditions representative of those expected to be found in real world Class C hazards. For example, several of the cited studies investigated configurations involving nichrome wire employed to initiate fires in polymethylmethacrylate (PMMA). In real world installations, nichrome wire is never employed for the conduction of power and PMMA is never employed as insulation for power cables. One of the cited studies did employ materials and conditions representative of those expected to be found in real world Class C hazards and the results of that study support DuPont findings;
- The results of recent testing performed by DuPont and Fike Corporation do not justify ROC 2001-61a. The results of recent testing by DuPont and Fike Corporation, employing materials and conditions representative of real world Class C hazards, indicate that the current Class A minimum design concentrations are sufficient for the protection of Class C hazards.
The Fire Suppression Systems Association (FSSA) has reviewed the cited work and the recent findings from DuPont and Fike Corporation, and is also in agreement with the DuPont findings.
To download the full presentation or for information on DuPont FE clean agent fire extinguishants, please visit www.cleanagents.dupont.com.
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