The RPCPA Fire Test Task Group Report

Transcription

1 3300 HIGHLANDS PARKWAY, STE 135 SMYRNA, GA TEL FAX The RPCPA Fire Test Task Group Report Background Reasons for Study 1- Many Authorities Having Jurisdiction were targeting plastic pallets as a potential fire hazard. 2- The National Association of State Fire Marshals had begun to conduct a campaign regarding their concerns of the possible fire hazard associated with the use of plastic pallets. 3- A proposal to NFPA 13 sought to increase protection for in-use plastic pallets. Research Objectives 1- To show that the most prevalent pallets used in today s marketplace need either a no-classification upgrade or no more than one classification upgrade. 2- To show that the most prevalent pallets used in today s marketplace can be protected the same as wood pallets using K-11.2 sprinklers. Committee Structure Two distinct committees were created. The Administrative Committee consisted of the manufacturers and others who contributed financially. This committee was responsible for administering the program and managing funding for tests and engineering support. The Technical Advisory Committee (TAC) was responsible for technical aspects of the program, such as test protocol and evaluation of test results. Members consisted of FM Global, the American Fire Sprinkler Association, the National Fire Sprinkler Association, Zurich America, Tyco Flow Control, Anheuser Busch, Fire Officials, TVA and interested members of the Administrative Committee. Technical Advisory Committee Fire Marshals from the following jurisdictions: Anne Arundel County, Maryland Newport Beach, California Morton Grove, Illinois American Fire Sprinkler Association American Plastics Council Anheuser Busch Buckhorn (A Myers Industries Co.) Cookson Plastic Molding Factory Mutual Global Linpac Materials Handling National Fire Sprinkler Association Nucon Corporation Orbis Corporation Rehrig Pacific Company Tyco Corporation Zurich America TVA Fire & Life Safety Administrative Committee Buckhorn (A Myers Industries Co.) Cookson Plastic Molding Linpac Materials Handling Nucon Corporation Orbis Corporation Rehrig Pacific Company TVA Fire and Life Safety (Non-voting) Additional Financial Contributors American Plastics Anheuser Busch Chevron Dow Chemical Imperial Oil Equistar Macro Solvay

2 Test Methodology Objective one was to be accomplished through commodity classification testing utilizing Underwriter s Laboratories small-scale calorimeter testing to establish a baseline for comparing plastic pallets to wood pallets. This methodology was developed by Factory Mutual Research Corporation and passed through the Swedish National Testing and Research Institute Fire Technology SP Report 1933:70 to UL. Objective two was to be investigated by conducting full-scale fire tests with K11.2 sprinklers and comparing the results to identical tests using wood pallets and K5.6 and K17 sprinklers. All testing needed to be completed during July and August 2001 so that a report could be created and sent with comments to the NFPA 13 committee by the October 5, 2001 deadline for comments. The Report on Comments meeting was conducted on October 24-26, Another method used to satisfy the objectives was a study to determine the most prevalent pallets in use today. Each plastic pallet manufacturer in the coalition was asked to report their top three selling pallets during the previous year and to estimate the total in use in the United States. TVA picked the most prevalent to use in conducting the calorimeter tests. After determining the more severe hazard pallets, these were chosen to be used in the full-scale tests. By choosing the more severe hazard pallets, most other plastic pallets would be acceptable if the test was successful. A review of previous plastic pallet fire tests was also conducted. Nine of the tests were calorimeter tests and were used to help determine our final conclusions, and also to help pick the pallets to be tested initially.

3 Calorimeter Tests The UL calorimeter consists of a 25 ft. diameter cone connected to an exhaust system capable of 60,000 cfm. It is fitted with instrumentation that measures convective and total heat release rates. Four measurements are taken: 1- Maximum one-minute average convective heat-release rate. This is helpful in determining how quickly a fire can be controlled. 2- Maximum one-minute average total heat-release rate. Maximum heat release rate is the combination of radiation and convective heat. This helps determine the potential for fire spread. 3- Effective convective heat-release rate the average maximum over five minutes. This helps determine fire severity. 4- Convective energy the total measured over ten minutes of the most severe burning. This helps determine the potential damage to the structure. Each of these measurements is compared to other known classified commodities and a classification ranking can be determined. The four rankings are averaged with a given density. This preliminary ranking and another with a different density are then averaged for the final ranking of the commodity. The densities are applied with a water applicator installed nominally 12 inches above the top of storage. It is activated manually when convective and total heat release rates indicate a certain sprinkler would operate with 10 feet of clearance.

4 Full-Scale Fire Tests Two full-scale fire tests were conducted using the K11.2 sprinkler to determine if a no-class upgrade was possible using a plastic pallet in combination with this design. The two tests conducted compared results with previously conducted tests using K5.6 sprinklers and K11.2 sprinklers with wood pallets. The advantages of the K11.2 sprinkler has been shown in the past and again showed some promising results. However, as a result of these tests, it was decided that further testing would be warranted to attempt to attain a noclass upgrade using the K11.2 sprinkler for protecting plastic pallets. The K17 sprinkler has been accepted by the NFPA 13 Technical Committee as capable of protecting plastic pallets the same as wood pallets based on previously conducted, similar tests.

5 Comments and Substantiations on NFPA Proposals The RPCPA test group submitted three sets of changes (called comments) to the proposals to change the NFPA 13 Standard concerning in-use plastic pallets. Included in the substantiations are all the tests conducted, the variables tested and their importance, and a list of previously conducted tests. Please see attached comments. NFPA 13 Changes Concerning Plastic Pallets The committee voted affirmatively on the following changes: Section Pallet Types When loads are palletized, the use of wooden or metal pallets shall be assumed in the classification of commodities For Class I through Class IV, when non-reinforced HDPE or PP plastic pallets are used, the classification of the commodity unit shall be increased one class (i.e. Class III will become Class IV and Class IV will become cartoned unexpanded Group A plastic) For Class I through Class IV, when reinforced HDPE or PP plastic pallets are used, the classification of the commodity unit shall be increased two classes (i.e. Class II will become Class IV and Class III will become cartoned unexpanded Group A plastic). Reinforced HDPE or PP plastic pallets shall be marked with a molded symbol to indicate that the pallet is reinforced For Class I through Class IV, when other than HDPE or PP plastic pallets are used, the classification of the commodity unit shall be determined by specific testing conducted by a nationally recognized testing laboratory, or shall be increased two classes No increase in the commodity classification shall be required for Group A plastic commodities stored on plastic pallets The requirements of Section and Section shall not apply where HDPE or PP plastic pallets are used and where the sprinkler system uses spray sprinklers with a K factor of 16.8 for ceiling only sprinkler protection The requirements of Section through Section shall not apply to non-wood pallets which have demonstrated a fire hazard that is equal to or less than wood pallets, and are listed* as such. Added to Section 3.3.X Reinforced Plastic Pallet. A plastic pallet incorporating a secondary reinforcing material (such as steel or fiberglass) within the pallet. A.3.3.x See Figures A.3.3.X (a) and (b) for illustration of a reinforced pallet g) When specific test data is available, the data shall take precedence in determining the required protection of idle plastic pallets. *Term listed means FM Approval OR UL Listing Recycling symbols will be included in the NFPA 13 supplements to further explain how the PE-HD pallets and the PP pallets can be identified in the field application (See Appendix B, Figure 1). Also a standard symbol will be added to the PE-HD and the PP symbols to indicate those that are reinforced (Appendix B, Figure 2). Also included in the NFPA 13 supplements will be diagrams of reinforced pallets (Appendix B, Figures 3, 4).

6 What Did We Learn? About the Test Methodology 1- The standard commodity (Class II) used in the tests was a 42 in. x 42 in. x 42 in. double tri-walled box with a sheet metal liner that fit exactly the footprint of the wood pallet. Plastic pallets rarely if ever have a footprint of 42 in. x 42 in. and consequently the standard commodity extended beyond the pallet or vice versa. This is definitely a variable for plastic pallets that was not tested with wood pallets that the classification rankings are based on. 2- The predominant plastic pallet size found in today s marketplace is 40-inch by 48-inch (GMA). As mentioned earlier, the RPCPA program tested the most prevalent pallets in the marketplace, and these tended to be 40-inch by 48-inch or larger. A 40-inch by 48-inch pallet creates a larger surface area than a 42-inch by 42-inch pallet, and therefore provides more material for fuel contribution during an actual fire test. It should, therefore, be recognized that even when not taking into account material types or pallet configuration, a 40-inch by 48-inch or larger pallet would be a more severe test than a 42-inch by 42-inch pallet. 3- A number of the plastic pallets were considered non-rackable. These are normally used for palletized storage situations. The test methodology used to compare these pallets to wood pallets was from rack tests. This meant that we were testing some plastic pallets in a scenario they would not be subjected to in the field. This also meant that the plastic pallet rested on the horizontal rack beans at various points on the pallet that may not have been the support point for that particular pallet, depending on size, configuration and reinforcements. This was another plastic pallet variable that was not tested with the wood pallets on which the classification rankings are based. 4- The method for deciding the time the nozzles would activate and water be discharged on the fire was based on 286ºF rated, 500 RTI (Response Time Index) sprinklers. In today s world almost all the sprinklers installed have a temperature rating of 165ºF, and well over 90 percent of the sprinklers have an RTI of less than 500. This means that the real world would put water on a similar fire much sooner than in the tests. Of course, this is true of wood pallets test comparisons as well. However, by introducing water earlier, less plastic would be involved in the fire, and any potential differences between wood and plastic would be reduced. 5- Three densities were selected (0.11 gpm/ft2, 0.21 and 0.31) in this test methodology so that at least two of the tests would be in the controlled region, indicating a fire reduced by nozzle operation, redeveloping and then eventually controlled. Any fires that are suppressed (no redevelopment of the fire) or free burning (not effected significantly by nozzle activation) are not valid for ranking the commodity. The controlled region for these tests is very narrow and it is easy to have plastic pallets with a Class II commodity on them to be outside the controlled region with the densities used. Thus, it would have been impossible to achieve the two density rankings and therefore a final ranking for some of the plastic pallets. This is important for developing future test programs. 6- The commodity classification methodology is the only accepted method for determining the effect of using plastic pallets instead of wood pallets. However, it is better suited for showing proper differences between commodities on wood pallets. The collapse variable is virtually eliminated when using wood pallets, and the commodity fits the pallet. About how Plastic Pallets Burn 1- In general, the quicker the loads collapsed, the lower the classification ranking. 2- Some correlation was noted indicating that the heavier the pallet (more plastic involved), the higher the classification ranking. 3- Injection molded polypropylene and structural foam high density polyethylene plastic pallets were no worse than a one-classification upgrade, with many (if tested further) that could qualify as no-classification upgrade pallets. 4- Polypropylene tends to melt, pool and burn slightly faster than high density polyethylene, but in the tests proved no worse than a one-classification upgrade, like many of the HDPE pallets.

7 5- The pallet production process methods tested (thermoformed, injection molded and structural foam) showed some differences in the burnability of some pallets, but there were no direct comparisons. Therefore, no concrete conclusions could be reached, but in general thermoformed pallets tend to be lightweight and non-rackable. Lighter weight pallets tend to collapse early and have lower ranking than heavier pallets. Injection molded pallets tend to be more dense, stay in place longer, be heavier and in general have higher ranking than structural foam. These are observations rather than conclusions, as the weight of pallets produced in each of production processes can vary substantially. 6- Reinforced pallets, whether containing steel or fiberglass reinforcement rods, tend to stay in place longer, allowing more plastic to burn and create higher rankings than non-reinforced pallets. 7- Only one two-way pallet was tested and it showed classification rankings about in the middle of the four-way pallet. No conclusions could be reached with the one test and no direct comparisons with four-way pallets could be established. 8- In previous idle pallet tests it has been shown that open deck pallets burn faster than solid deck pallets. In the in-use tests, other variables were more prominent, and the differences were not clear. With solid-flat bottom wood pallets, an increase of 20 percent to the density is mandated by the NFPA storage standards. The reason is the ease of spread and increased burning commodity for the sprinklers to control. This data could be used to say that solid-deck plastic pallets burn faster than open deck plastic pallets. However, with the test arrangement used in the calorimeter tests (two pallet loads-by-two pallet loads-by-two pallet loads), there was not enough commodity to fully analyze the effects of the smoothness of the underside of the pallet.

8 Where Do We Go From Here? Education 1- The public and AHJs have to recognize the new standard, be aware that all plastic pallets do not burn extremely fast, and that the test program shows that some in-use plastic pallets are no worse than wood and that almost all pallets create a hazard no worse than a one-classification upgrade. 2- Conduct professional, objective presentations showing fire test conclusions and the amendments to the NFPA standard. This will address the concerns of fire marshals, building officials and industry organizations. 3- Develop a plan to reach model building code and risk management sectors with our message in order for them to make more informed decisions when evaluating the plastic pallet hazard. Testing 1- Other pallets, such as low-density polyethylene pallets, rotational molded pallets and pallets containing other resins should be tested. If this is not done so that the hazard is understood ahead of time, one of these manufactured pallets could be in a fire or tested in an improper manner and all plastic pallets will take the blame. In this era of high insurance costs, being ahead of the game and understanding the greater hazard (if there is one) is vital in keeping these costs to a minimum and in balance with reality. 2- Idle pallet testing is the next big testing hurdle. If an idle plastic pallet test program could show some pallet types not requiring the protection now suggested (The solid deck idle pallet reductions have been taken out of the NFPA 13 standard due to one or two tests with other pallets and lack of sufficient data), more marketing opportunities would open up. Since the idle pallet storage hazard is so different from the in-use hazard, many different variables could be analyzed and a better fire hazard pallet could be produced. Prior testing has shown that idle solid deck nestable pallets not only can have more pallets stored in a certain height, but in many cases do not burn as severely as other pallets. More testing, and possibly a different type of testing criteria, may be needed to satisfy the NFPA committee requirements. 3- From the above discussions of the test methodology used and its inherent problems, a new methodology (or a revised methodology) would be very important for the RPCPA to pursue. A more simplified, less expensive, real world protocol would give all plastic pallet manufacturers a method to experiment economically, and ultimately build a better plastic pallet.