Plastic Container as Expanded vs. Non-Expanded?

3/8/2021

Can you help explain two entries in NFPA 13-2019 Table A.20.4(b) for "Empty Containers" on page 418?

Rigid plastic (not including PET) up to 32-oz. (1L) is non-expanded.
Rigid plastic (not including PET) greater than 32-oz. (1L) is expanded.

What are they referring to? Is this a one-gallon PE bucket? A 64-oz. detergent bottle? Milk crates?

I guess my question is - what is a rigid plastic container?

There's a huge difference if it needs to be treated as an Exposed Expanded Group A plastic versus Non-Expanded.

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8 Comments

Franck

3/8/2021 09:42:03 am

It could be any plastic container that is stored empty, including plastic boxes (as Tupperware).
The difference between expanded and non expanded is related to the volume of air around the plastic because of the content inside the container itself.
If you have more air, you have less plastic by volume, but the fire will have a much higher heat release rate, thus requiring a higher sprinkler density.

Franck

3/8/2021 09:44:12 am

By the way, you have the same type of differenciation with corrugated cardboard.
Flat corrugated cardboard storage is a class III while empty corrugated cardoxes (already folded in a box shape and stored empty) is to be considered as a class IV commodity.

CJ Bonczyk

3/8/2021 10:16:15 am

PET's are just Class IV. Polyethylene terephthalate (PET) is a versatile plastic from the polyesters. PET's are items such as water bottles, liquid medicine containers, soft drinks, sport drinks, single-serve water, ketchup, salad dressing, vitamins, vegetable oil bottles and peanut butter containers, take out food storage.

Rigid Plastic containers are exactly what they are...just any form of rigid plastic container/item based on volume of plastic makeup. It could be jugs, crates, toys, car parts etc. The key is whether it is Expanded or Nonexpanded. Nonexpanded are high density plastics (usually blown into shapes, or formed into shapes). Expanded are made from various resins creating bubbles trapping air thus creating a much less dense plastic. Those are items like polystyrene's, coffee cups, insulation boards etc. Expanded is obviously the more dangerous of the two.

Franck

3/9/2021 03:53:20 am

You are fully right, with one exception.
You are considering the definition of the material as a commodity, not its beahvior when exposed to a fire.

Non expanded rigid plastic empty containers are considered (for fire protection design) as expanded plastic when it is an empty container of 1 l (32 oz) or greater.
The classification is not based on the nature of plastic (expanded vs non expanded) in that case, but on its behavior, as a material shape, during a fire event.

The same container with water (or any non combustible liquid) inside becomes a class I for volumes up to 30 l (5 gal) or a class II for volume greater than 30 l (5 gal).
The reason is the same.
The volume of plastic is the same, but when exposed to a fire, the non combustibe liquid will absorb heat and help to extinguish the fire if the container melts.

Because of different behaviors when exposed to fire of a same packaging material depending on its content (empty, non combustible liquid, flammable liquids, non combustible powder...), the final commodity classification can be different than the pure classification of the material itself.

3/9/2021 02:57:25 pm

Franck,

It's just hard to accept/understand how pallet loads of empty 5 gallon buckets (upside down so it's not an open top container) will burn significantly worse than idle plastic pallets.

I can protect idle plastic pallets on the floor/racks to 35 feet in a 40 foot building using K17 at 52 psi ESFR heads.

Calling the 5 gallon buckets an exposed (since they are not in a carton), expanded, Group A plastic makes it very very difficult to protect. The only option is per 23.7 with a 25 foot max, vertical barriers, K25 @60 psi, etc.

Do you know of any testing that has been done or why this was added in 2016?

Dan

3/8/2021 10:24:26 am

This has been something we have been kicking the tires about for a while now. More so the politics of it for existing installations. Essentially there is rigid plastic containers and then non-rigid (flexible) containers where it is expected that the container lose shape very quickly (like thinner PE materials for example). Franck has it from there. If I can get air all around the formed container that retains it shape longer, then my heat release will prove substantially greater than an otherwise glob of solid plastic. Is the heat like EPS or other well-noted expanded plastics? Not quite....but definitely more than a typical solid plastic form - and more so approaching expanded plastics. Reinforced plastic pallets aren't treated as nonexpanded plastics for similar reason. Obviously this has implications for new installations (especially if not bid as such) as well as existing ones. Lots of systems installed for such assuming nonexpanded plastic.

haziq link

9/25/2022 10:11:12 pm

Have you noticed how plastic containers are often used in the cosmetic field for packaging? Be it a foundation, eyeshadow, lipstick or blusher, most of them come with the plastic container.

Some of you might wonder why they use a plastic container as packaging instead of any other materials such as glasses or aluminium as it will look more pretty and elegant.

Therefore, in today’s write up, we will discuss why the plastic container is the best option for cosmetics’ packaging and how you can find the best packaging for your products.

Christopher Jones

2/10/2023 11:53:41 am

I have (2) different scenarios with the same product (empty 5L HDPE containers) from 2 different manufactures and package slightly different both having cardboard dividers and on wood pallets. I am leaning towards exposed expanded encapsulated Group "A" on the pallet load without cardboard sides due to the row of containers enclosed in plastic bags. The pallet load with the cardboard partial sides and full cardboard top would be the same due to having only partial sides. Any help would be greatly appreciated. Included is a link to some photos. Thanks.

https://metcon-my.sharepoint.com/:f:/g/personal/cjones_bgcompanies_com/EhHRLMbMjxdKgBAatEslOO0Bq-AT_faZOtAT3r0bcv2qDQ?e=F7bKIa

Plastic Container as Expanded vs. Non-Expanded?

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