VN: For Problem 122, I wanted to check if I was breaking down the solution properly. I'm not seeing the end solution of EH1 in NFPA 13 Table 13.2.1.
Could you take a look at the assumptions below and let me know if I'm missing something or assuming the incorrect storage configuration? Below is the information extracted from the problem statement: synthetic fiber (less than 50/50) - Class III (NFPA 13 Table A.5.6.3) natural fiber clothing - Class III (NFPA 13 Table A.5.6.3) rayon - Class IV (NFPA 13 Table A.5.6.3) unexpanded plastics Since movable racks, treat as multiple row rack storage. Storage directly on shelves more than 50% open, so exposed storage. Storage height 10'6". Assuming unexpanded plastics as the worst case, I'm ending up at either OH2 or EH2 depending on max ceiling height which isn't specified in the problem.
3 Comments
Chris Campbell
10/12/2020 12:01:13 pm
The majority of your analysis is correct, with the exception of unexpanded plastics being the worst case. Per NFPA 13 Section 5.6.3.4.1(3), Class IV commodities can contain 5-15% by weight and 5-25% by volume of Group A plastics. Therefore, the worst case classification is Class IV. Per Table 13.2.1, Class IV commodities on racks with a max storage height of 10-12 feet should be designed to the EH1 curve.
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Joe Meyer
10/13/2020 06:01:45 am
Chris - would you recommend a change to the guide at all here?
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Chris Campbell
10/13/2020 06:42:09 am
I think this question is hard but fair. It requires you to recall or lookup the commodity classification definitions as well as the definition of open rack storage. While this is probably on the harder end of NFPA 13 questions that one would see on the exam, I think it is good to leave as is.
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