Problems With Plan Review? 

Informal Interpretations Assist Contractors, AHJs

The informal interpretations featured in this issue of Sprinkler Age address plan review concerns. AFSA’s informal interpretations are provided to AFSA members by AFSA Vice President of Engineering & Technical Services Roland Huggins, a P.E. registered in fire protection engineering; Phill Brown, a NICET IV certified automatic sprinkler technician and NFPA Certified Fire Protection Specialist (C.F.P.S.); and Tom Wellen, P.E., senior fire protection engineer. These opinions are provided for the benefit of the requesting party, and are provided with the understanding that AFSA assumes no liability for the opinions or actions taken on them.

SUBJECT: Tire Recycling Occupancy Classification

QUESTION: “We have a customer who will be recycling tires by a crushing and shredding machine. The tires go through the grinding process on conveyors. When the process is complete, the tires are pebble-sized pieces and then loaded in totes and loaded on trucks or stored outdoors for shipment. The customer will also be storing some tires per Chapter 13, Miscellaneous Storage. The Authority Having Jurisdiction (AHJ) has concerns regarding the amount of dust that is created by this process. While we know there will be some dust created in this process, we contend that the tire grinding or shredding process and the dust created requires protection per A.5.4.1, which would be extra hazard (Group 1). We believe that the grinding/shredding of tires is considered rubber reclamation, or milling process. Are we correct in the assumption that the above-mentioned processing with dust created would fall under the requirements of A.5.4.1(7)? Is there a threshold for the amount of dust created by this process? Can Table 13.2.1 be applied for miscellaneous tire storage, stored portable, on side or tread, stacked up to 12 ft when an extra hazard (Group

1) system is installed in the building as long as the building owner complies with the definition of Miscellaneous Storage (1,000 ft2 maximum pile size, etc.)?"

ANSWER: In response to your question we have reviewed NFPA 13, Standard for the Installation of Sprinkler Systems, 2013 edition as the applicable standard. Our informal interpretation is that the occupancy class selected seems appropriate for the dust hazard and the storage criteria should be applied for the tire storage and the finished product. The processing of the tires into a smaller component does create dust and needs to be managed. The AHJ has a legitimate concern regarding the explosion hazard. You’ve done your part regarding the sprinkler protection but other protection features such as explosion venting should be addressed (see NFPA 652, Standard on Combustible Dusts and NFPA 654, Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing, and Handling of Combustible Particulate Solids). This is likely outside your scope of work. NFPA 13 Section 5.4.1 indicates that extra hazard (Group 1) occupancies shall be defined as occupancies or portions of other occupancies where the quantity and combustibility of contents are very high and dust, lint, or other materials are present, introducing the probability of rapidly developing fires with high rates of heat release but with little or no combustible or flammable liquids. Regarding the processing of the tires, the grinding or shredding of tires is not technically considered rubber reclamation or milling process. Reclaimed rubber is cured rubber that has passed through a thermo-chemical process that softens and swells the rubber. The process reduces the rubber’s viscosity by shortening the polymer chain by mechanical shear and chemical actions. This application is reducing or processing the size of the synthetic rubber into crumb or granulate particles. The chemical make-up of the rubber or synthetic rubber

is not being changed. This would be more aligned to ordinary hazard (Group 2) occupancy but the dust and lint suspension hazard would kick it back to the extra hazard (Group 1) occupancy. The tires prior to grinding could be considered miscellaneous storage. Note that there is a difference in the definition of Miscellaneous Storage in Section 3.9.1.18 and Section 3.9.4.4 for Miscellaneous Tire Storage. This is defined as storage of rubber tires that is incidental to the main use of the building; storage areas do not exceed 2,000 ft2 , and on-tread storage piles, regardless of storage method, do not exceed 25 ft in the direction of the wheel holes. The definition provides five different acceptable storage arrangements. The criteria of Table 13.2.1 can be applied if the storage arrangement meets the definition. Chapter 18 criteria would apply when the storage exceeds the definition of miscellaneous tire storage. Lastly, after the tire is crumbled or granulated, the product is no longer considered a tire. The criteria of Chapter 18 or Table 13.2.1 for tires would no longer apply since the configuration or the surface area has changed although the material remained the same. A tire is made of some natural rubber but is mostly synthetic rubbers. Annex A.5.6.3 and Table A.5.6.4.1, Examples of Group A Plastic Commodities shows that synthetic rubber is a Group A plastic. Protect the final product and its packaging according to the applicable storage chapter. This could be Chapter 13, 15, or 17 depending on the quantity and arrangement of the final product.

SUBJECT: Museum Displays Creating Obstructions Greater Than 4-ft Wide

QUESTION: "We have an educational facility with an existing fire sprinkler system. The owner would like to mount a flying Pteranodon statue (dinosaur) from the ceiling in their mineral museum and