Exploding Plastic Kegs!

[IainMcLean]

morning all: just saw this tweet:

@MelissaCole BREWERS! READ THIS ABOUT PLASTIC KEGS PLEASE -be safe xx
http://t.co/2QHFUbXq

 

[crd0902]

Wow that's unreal. Think I'll stick to my 7 psi and steel kegs. Interesting read but cheers.

 

[seravitae]

Hmm. Maybe it's a fabrication issue. If they are failing at seam welds, maybe they should be rotamoulding these so they don't have seam welds at all.. Or thicker plastic.

 

[bigfridge]

If they are failing at seam welds, maybe they should be rotamoulding these so they don't have seam welds at all.. Or thicker plastic.

Very true,

We have just started importing plastic casks and they have a steel band around the middle and are rotomoulded (just like a very large plastic bottle).

Seems the best way to go.

 

[tricache]

Plastic is always a big "funny" under big pressure (they have listed between 30PSI and 100PSI in that article) but I would have thought they would go under the same testing as metal cylinders....I would assume anyway

 

[bigfridge]

... I would have thought they would go under the same testing as metal cylinders....I would assume anyway

Yes they do.

Under AS 4343-2005 they are designated Hazard Level E

View attachment Category_E.pdf

 

[tricache]

Yes they do.

Under AS 4343-2005 they are designated Hazard Level E

View attachment 57960

400 MPa Pressue Test!!!! WHOA!!

 

[komodo]

Whats wrong with stainless...

 

[WeaselEstateBrewery]

Each time I force carb my kegs, I wonder if a corny has ever exploded. Never heard about it happening, and I hope I am not there if it ever happens :lol:

 

[hsb]

Whats wrong with stainless...

Did you actually read the linked article?

 

[///]

The Cypherco casks and the PKA are very different beasts and should not be bought up in the same conversation.

I was with Jeff Gunn a week after the incident as the fatality occurred on an IDD wash/racking line and fingers were being pointed by PKA in all directions. There are more anecdotal reports of issues with the PKA items, unfortunately the brewers shrugged thier shoulders and just kept going on with their day throwing the damaged items out.

There is an alternative to the PKA kegs, have the info at work, and those are one use and look like a large PET bottle. (not tobe confused with an EcoKeg). I'll find it and put it up.

Scotty

 

[IainMcLean]

Each time I force carb my kegs, I wonder if a corny has ever exploded. Never heard about it happening, and I hope I am not there if it ever happens :lol:

I once popped a ding out of one of mine by doing just that!

 

[tricache]

I once popped a ding out of one of mine by doing just that!

F#ck that!! I'm sticking to PET bottles :lol:

 

[ausdb]

Hmm. Maybe it's a fabrication issue. If they are failing at seam welds, maybe they should be rotamoulding these so they don't have seam welds at all.. Or thicker plastic.

Or maybe its a process environment related issue?

Reading the linked article the term "Pressurised Keg washer" came up a lot and I wonder if the interaction of the cleaning chemicals used and the working pressure on the plastic has been investigated thoroughly? I recently worked on a failure of a product made of ABS plastic which for all intents and purposes had started to lose its structural integrity. The plastic softened and would crack at stress points especially where it was loaded, which I came to learn was a phenomenon called Environmental Stress Cracking. In my situation the residue of cooking oils and grease that coated the item was the first clue, it was then a case of understanding what was in the greasy goop covering the item that was causing it to fail.

I have also had some plastic parts out of better bottle fittings (airlock, racking assemblies) fail after they had been left soaking in percarb and star san for a while, maybe there is something going on like that with those kegs?

 

[pk.sax]

I'd pay more attention to the point where the asme had originally agreed to the ss keg design based on a safety factor of 10. That isn't exactly crazy for a pressurised vessel subject to sometimes rough handling and temperature variances in transit. The thermal expansion of the filled fluids is enough to expose any weaknesses. By designing the plastic kegs to barely 3-4 times serving pressure and not that much of a margin over handling points they ask for trouble. Of course, being a plastic it won't ever behave exactly to spec, manufacturing variability takes care of that. Once in a while some poor sod lets his guard down and gets caught out by a really close tolerance keg.

In fact, the euro kegs that come rubber coated are brilliant. They have lot if shock and rough handling tolerance built in. In the end, get what you pay for.

 

[bigfridge]

In fact, the euro kegs that come rubber coated are brilliant. They have lot if shock and rough handling tolerance built in. In the end, get what you pay for.

Actually the opposite is true.

The use of the plastic coated kegs have been discontinued in Europe due to safety concerns. When they are dropped they can ding and crack but as the plastic coating pops out there is no external indication of potential problems. The 'ding' also reduces the effective capacity and causes the keg to be rejected as an underfill on automatic filling lines.

The coating was generally thought to be a good way of reducing the noise made by handling the kegs and they were also offered as having built-in insulation to keep their temperature during serving outside. Unfortunately someone forgot that it takes much, much longer to cool down an insulated keg in the first place.

 

[pk.sax]

Aha. Good ol voice of first hand experience /knowledge great to know, didn't think of that.
Back to the steel hey.

 

[black_labb]

With the right design and equipment you could probably insulate the keg and have a glycol line or similar circulating through the inside eliminating the need for the keg to be in a cool room. This is vastly superior as the keg could be right at the bar and would shower everyone in beer when it explodes!

 

[bigfridge]

Aha. Good ol voice of first hand experience /knowledge great to know, didn't think of that.
Back to the steel hey.

Still fine for home use of course - but don't try to make a boiler out of them. They stink a bit when you light the gas burner