On July 17th, an explosion occurred during the inflation of a new tire in Leshan, Sichuan, resulting in a tragic accident with fatalities.
Similar incidents have been happening occasionally within the industry. Experts have typically focused on factors such as tire quality, wheel maintenance, and operational standards to explain these explosion accidents.
Recently, an expert at a major domestic tire company has proposed a completely different theory.
Explosions on the Assembly Line
This expert, who is currently retired but has returned to a technical position at a tire company, has dealt with many challenging tire-related issues throughout his career.
According to him, tire explosions occasionally occur on wheel assembly lines in automotive factories, which is not new. He explained that the conditions on the assembly line are very similar to those at tire repair shops where tires are dismounted and mounted.
The expert noted that around 2014, a leading domestic commercial vehicle manufacturer began switching from steel-belted radial tires with inner tubes (commonly known as tubed tires) to tubeless steel-belted radial tires (commonly known as radial tires). During this period, tire explosions were happening frequently, with 3-4 incidents occurring each month, often causing injuries.
The car manufacturer conducted various investigations, consulting multiple tire companies for on-site discussions, but no conclusions were reached. They even sought assistance from domestic fire safety experts, but no further progress was made.
Identifying the Culprit
Through interviews with multiple individuals involved in the incidents, the expert discovered several common factors in the explosions:
The tires involved were all tubeless steel-belted radial tires.
The explosions occurred after the tires were inflated and temporarily placed in storage.
A burnt rubber smell was present at the site.
The exploded tires showed signs of burnt powdery residue inside.
Based on these observations, the expert concluded that the true cause of the tire explosions was dust explosions.
Dust Explosion Explained
A dust explosion occurs when combustible dust, within its explosive limit range, encounters a heat source (such as an open flame or high temperature), resulting in an instant explosion with powerful destructive force.
After confirming that dust explosions were the primary cause, the car manufacturer took action. They implemented measures that required all tire suppliers to refrain from providing repaired tires. Workers on the wheel assembly line were also instructed to ensure that no powdery residue or debris remained inside the tire before installation.
As a result, the incidence of tire explosions significantly decreased.
Relevance to Recent Tire Inflation Explosions
In recent years, tire inflation explosions have been happening more frequently in China, and this issue may be linked to the previous findings. Since the national standard for freight trucks was changed two years ago, the load-bearing standards were adjusted, and almost all commercial truck tires have been replaced with tubeless steel-belted radial tires.
It is worth noting that tires with inner tubes are less likely to experience a dust explosion because the inner tube isolates the air pressure, preventing the conditions necessary for a dust explosion even if dust is present.
Of course, the causes of tire explosions can be varied, and product quality issues cannot be ruled out. Each incident requires a detailed on-site investigation to make a final determination.
