Office Chair Hydraulic Explosion

Office chair hydraulic explosion usually refers to the sudden explosive phenomenon of pneumatic lifting swivel chairs caused by component defects, which mostly occurs in low-quality pneumatic rod products.

Explosion Causes

1. Quality Defects of Pneumatic Rods: The pneumatic rod (gas spring) is the core component for the lifting of swivel chairs. Insufficient wall thickness, substandard steel strength, or defects in the welding process can cause the high-pressure gas inside (usually nitrogen) to break through the wall due to friction heating or pressure fluctuations during frequent lifting and lowering, triggering an explosion.
2. Impure Gas Composition: Legitimate pneumatic rods should be filled with high-purity nitrogen and other inert gases. However, some low-quality products use compressed air instead to reduce costs. The oxygen in the air accelerates metal oxidation at high temperatures, reducing the wall strength. At the same time, the gas has a larger coefficient of thermal expansion, significantly increasing the risk of explosion.
3. Lack of Explosion-Proof Measures: According to national standards, a explosion-proof steel plate with a thickness of ≥2 millimeters should be installed between the pneumatic rod and the seat cushion to block flying debris in the event of an explosion. However, spot checks show that some products are not equipped with such plates or have plates with insufficient thickness, failing to provide effective protection.

Typical Cases

• In 2007, Zhoushan, Zhejiang: An office chair suddenly exploded while adjusting its height, with debris piercing through the ceiling.
• In 2009, Jiaozhou, Shandong: A 14-year-old boy died after a pneumatic chair exploded, with the top rod piercing into his body.
• In 2017, Anhui: Debris from an exploding office chair pierced through a computer case, causing property damage.
• In 2020, a spot check by the State Administration for Market Regulation: 23.3% of office chairs were unqualified, with 17 batches being swivel chairs. The main issues were substandard high- and low-temperature resistance of the pneumatic rods and the lack of explosion-proof steel plates.

Prevention Measures

1. Choose Legitimate Products: Prioritize purchasing brands that have passed national safety certifications (such as GB/T 10357.4-2013). It is recommended to choose products priced above 200 yuan and avoid buying "three-no" products (products without a proper brand name, factory address, or production license).
2. Check Pneumatic Rod Performance: Observe whether the lifting and lowering are smooth during adjustment, without stuttering or abnormal noises. Press the seat cushion with your hand to feel whether the explosion-proof steel plate is present (there may be no support if the thickness is insufficient).
3. Avoid Frequent Lifting and Lowering: Reduce continuous height adjustment operations in a short period to prevent a sudden increase in the internal temperature of the pneumatic rod.
4. Regular Inspection and Maintenance: For swivel chairs that have been in use for more than 5 years, it is recommended to replace the pneumatic rod or contact the manufacturer for a safety inspection.