Hazard Class of Recycling Plastic Solid Storage?

7/29/2020

We're designing a fire sprinkler system for plastic (Group A material, unexpanded polyethylene) recycling site. We are designing only for the depot area. There are raw materials stored as solid blocks up to ...We've raw material stored as solid blocks up to 12 feet (3.6 meters).

I am thinking this should be considered rack storage under NFPA 13 Section 16.2.1.2 (2016 Edition) for Protection Criteria for Rack Storage of Class I Through Class IV Commodities Stored Up to 12-ft (3.7m) in Height.

Am I wrong considering this? Note that compacted material will have a lower combustion propagation velocity than generic goods. Any ideas? Thanks in advance.

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3 Comments

Franck

7/29/2020 12:24:11 pm

Is it really stored in rack or more like a compact pile storage ?
Maybe it is more to be considered as pile storage (unexpanded gr. A exposed plastic).
I don’t see any reason to consider it as a class I to IV commodity unless it is free flowing plastic (equivalent to class IV)
The only question would then be is it stable during a fire (table 15.2.2.5(a) column E), i.e EH gr 2 or 0.7 gpm/sq ft over 2500 sq ft depending on your ceiling height, or unstable (column A of the same table), i.e. 0.2 to 0.4 gpm / sq ft over 2500 sq ft depending on the ceiling height.

Pete D.

7/29/2020 04:22:08 pm

Franck has identified the appropriate area of the standard correctly. Something important to consider and frequently missed that will apply if pick up other areas of the contract such as the sort- Empty plastic containers are considered expanded plastic despite being made from unexpanded plastic Due to them being empty (full of air) the burn properties are nearly the same as foam. If you compress and bind them into blocks or process (melt) them into blocks they become unexpanded again. You described solid piled unexpanded plastic.

PETER

7/30/2020 01:49:10 am

It's a compact pile storage, 3 solid blocks putted one on the top of each other to a maximum height of 3,6m (12ft).
I'll consider it as unstable because no enclosures or containers or something that keeps them alligned or locked.
I'll go for section 15
Thank you for your time!

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