Another exploding boule

We have another entry in our continuing annals of exploding boules.

Today Paris Match reported that a family was having a cookout early this afternoon in Boulou, a small village near Perpignan. The barbecue grill had been set up in the garden and a 31-year-old man was doing the cooking. Unknown to him, a petanque boule had been left inside the grill and forgotten. The heat of the fire caused the boule to explode. Fragments of the exploding boule struck the man in the head— he was dead by the time a doctor arrived on the scene.

No information about the boule was reported (although we do have one photograph), but I will nevertheless speculate that it was a cheap leisure boule similar to the boule that killed a Thai player in 2017 when it was heated. In any event, it is becoming increasingly clear that boules and heat do not mix. So, for you folks out there who play during wintry weather and heat your boules, the moral of this story is— Be aware that what you’re doing can be very dangerous, and please be extremely careful.

L’Independent has published a photo of the remaining part of the boule.

UPDATE
An English-language story by “Peter Allen” that appeared on various web sites, including the website of the Daily Star asserted that “There are no other known examples of anyone being killed by an exploding petanque ball.” That is incorrect. In September 2017 a player in Thailand was killed when a boule exploded while he was heating it on a stove. Allen’s story also asserts that in July 2017 a petanque ball left in a fire pit on an unidentified beach exploded, injuring a teenager. I cannot verify that story, and I wonder if it might be a garbled account of the incident in Thailand.


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More exploding boules

We’ve blogged before about exploding leisure boules, but until now no-one has been killed or seriously injured by such an explosion. Today, however, a Thai newspaper reports that a player in Thailand has been killed by an exploding petanque boule. The story is rather bizarre.

Apparently some Thai players believe that soaking boules in water and then heating them can somehow improve a player’s ability to put spin on the boules. In preparation for an after-work game with his buddies, a firefighter named Decho Phetchnin had been heating his set of 3 boules on an “Ang Lo” burner for about two hours when one of the boules exploded, blowing the burner apart and scattering debris in a 10-metre radius. The explosion occurred while Decho was bending over the burner stirring the boules. A metal fragment from the exploded boule struck Decho in the forehead, piercing his skull and killing him instantly.

The photo that accompanies the story looks like the boule might have been a leisure boule (rather than a competition boule), although it’s hard to be sure. The dust visible in the picture suggests that the boule (like many cheap leisure boules) was filled with sand.
CLICK for a larger image


Exploding leisure boules

On Saturday, September 4, 2016, in the German town of Nettetal, near Düsseldorf, during a neighborhood party, in the middle of a tent erected for the event, a petanque boule spontanously exploded. The explosion ripped a hole in the ceiling of the tent and left a small crater in the ground, but nobody was injured. A Düsseldorf bomb squad removed the remaining seven boules in the set and safely detonated them.

The investigation of this incident is still ongoing, but it recalls a similar incident that occurred in Switzerland in 2009.  In that incident, the Swiss Federal Laboratory for Materials Science and Technology (EMPA) analyzed the remaining boules in the set in an effort to determine the cause of the explosion. The boules in question were cheap leisure boules manufactured by Dutch company Nebus BV. They had thin metal walls and were filled with a sand-like mixture (French news reports referred to it as “mortar”) to bring them up to proper weight. The sand was damp and contaminated with iron filings.

The moisture in the sand corroded the iron filings. Inside the sealed boules, in the absence of oxygen, that chemical reaction produced hydrogen gas, which caused high pressure inside the boules. The cheap boules had poorly welded seams. Under the pressure of the hydrogen gas, the seam of one of the boules failed and the boule exploded. It literally blew its top.

In the 2009 incident the set of boules was sitting on a shelf in its original packaging. In that incident, the Swiss department store chain Coop, which sold the sets, immediately stopped selling them and launched an aggressive recall campaign.

On the Wednesday following the explosion in Nettetal, the German federal government issued a press release warning the public of the danger of cheap boules. The German Petanque Federation (DPA) recommended buying certified boules and shopping for boules in specialty stores rather than in supermarkets.

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The boules that exploded in Switzerland in 2009. The boules were stored in the black bag shown on the right. Note the top of the exploded boule on the left side of the shelf, the sand scattered about the shelf, and the dent in the shelf wall at the right. It looks like the black bag must have been standing upright against the wall when the boule exploded.

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Closeup of the bottom half of the exploded leisure boule in its original packaging.

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Cross-section of another boule in the set. In addition to the sand filling, note the thinness of the metal shell.


For an interesting short video showing EMPA testing cheap boules, see THIS.

For EMPA diagrams comparing cheap leisure boules to competition boules, see THIS.

The EMPA engineering failure analysis, “Investigation into the mechanisms leading to explosion of pétanque balls”, is available HERE.