Hydraulic Office Chair Explosion

The explosion of hydraulic office chairs is a sudden phenomenon caused by component defects, often occurring in low-quality pneumatic rod products, and can result in serious injuries or fatalities in severe cases.

Causes of Explosion

The explosion risk of hydraulic office chairs (pneumatic lift swivel chairs) primarily stems from design or manufacturing defects in the pneumatic rods. These rods achieve lift functionality by filling with inert gases (such as nitrogen) and utilizing pressure differentials. However, the following issues can trigger explosions:

1. Thin Walls of Pneumatic Rods: To reduce costs, low-quality pneumatic rods may use metal tubes with insufficient wall thickness, which cannot withstand high internal pressure and are prone to rupture during frequent lifting or temperature changes.
2. Insufficient Purity of Inert Gas or Replacement with Compressed Air: Legitimate pneumatic rods should be filled with high-purity nitrogen, but inferior products may mix in air or directly use compressed air. The oxygen in the air can support combustion at high temperatures, exacerbating the explosion risk.
3. Rapid Temperature Increase Due to Frequent Lifting: When the gas inside the pneumatic rod is compressed, the temperature rises. If the tube material is not heat-resistant, it may rupture due to thermal expansion. For example, rapidly and continuously adjusting the seat height accelerates the temperature increase.

Incident Cases and Hazards

According to a spot check by the State Administration for Market Regulation, the failure rate of office chairs reached 23.3% in 2020, with 17 batches being swivel chairs. The main issues were the pneumatic rods' failure to meet high- and low-temperature resistance standards and the lack of explosion-proof steel plates. Since 2007, multiple explosion incidents involving pneumatic lift swivel chairs have occurred across China, resulting in injuries and fatalities:

• In 2007, Ms. Lou's chair exploded in Zhoushan, Zhejiang, puncturing the seat and embedding fragments up to ten centimeters into her body.
• In 2009, a teenager in Jiaozhou, Shandong, was impaled in the buttocks by a lifting rod while adjusting a pneumatic chair, leading to death from blood loss.
• In 2013, Ms. Liu's chair exploded in Fujian, propelling a steel tube about two centimeters in diameter through her lower body, with multiple fragments retrieved from her abdomen.

Preventive Measures

1. Choose Legitimate Products: Prioritize brands priced above 200 yuan that have passed national safety certifications, and avoid purchasing unbranded products.
2. Inspect Pneumatic Rod Quality: Observe whether the seat lifts smoothly without jamming or unusual noises when adjusting. If the pneumatic rod is difficult to lift or emits abnormal sounds, it may have internal defects.
3. Confirm Installation of Explosion-Proof Steel Plate: Legitimate products install an explosion-proof steel plate with a thickness of at least 2 millimeters between the seat cushion and the pneumatic rod to block explosion fragments. When purchasing, you can request the merchant to provide a product cross-section diagram or disassemble it for verification.