Exploding leisure boules: do NOT heat your boules

A few petanque players in the USA brave the rigors of winter and continue to play with snow on the ground. Some of those players put their boules on some kind of device to warm them up. The moral of this post is that boules and heat do not mix.

2009

In 2009, a new, unsold set of leisure boules sitting on a shelf in a storeroom in a store in Switzerland spontaneouly exploded. Response to the incident was swift. The Swiss department store chain Coop, which sold the sets, immediately launched an aggressive recall campaign. A fews days later 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.

The Swiss Federal Laboratory for Materials Science and Technology (EMPA) analyzed the remaining boules in the set. They were cheap leisure boules manufactured by the Dutch company Nebus BV. Like all such boules, they had thin metal walls with poorly welded seams and were filled with a sand-like mixture (French news reports referred to it as “mortar”). EMPA found that the sand was damp and contaminated with iron filings. The moisture in the sand corroded the iron filings. That chemical reaction produced hydrogen gas, which caused high pressure inside the boule. The seam of the boule failed and the boule exploded. It literally blew its top.

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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. 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.

2016

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.

2017

The first player to be seriously injured (killed, in fact) by an exploding leisure boule was a player in Thailand. 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 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. A photo of the boule shows what appears to be a cheap leisure boule. CLICK for a larger image

2018

The second death due to an exploding boule occurred on April 19, 2018. A family was having an afternoon cookout in Boulou, a small village near Perpignan. The barbecue grill had been set up in the garden and a unnamed 31-year-old man was doing the cooking. Unknown to the man, 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. Again, a photograph of the boule seems to show a cheap leisure boule.

At the same time, there was a report that a teenager was injured in 2017 by the explosion of a petanque ball left in a fire pit on an beach. The story was probably a confused version of the death of the Thai player.


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