Office Chair Shaking and Explosion

The shaking of an office chair may be related to issues with the gas spring, posing an explosion risk. However, genuine products usually do not explode, while the risk is higher for inferior products.

The gas spring is the core component that enables the height adjustment function of an office chair. Its principle is similar to that of a bicycle pump, where the piston is pushed by high-pressure gas inside to achieve height adjustment. Genuine products are filled with inert nitrogen, which can withstand thousands of kilograms of pressure, offering high safety. However, inferior gas springs may have the following problems that increase the risk:

• Impure gas: If replaced with compressed air by unscrupulous manufacturers, the oxygen in the air can erode the metal inner wall, making the steel brittle. Coupled with the heat generated by daily lifting and lowering friction, the internal pressure will rise steadily. Explosions may occur during summer exposure to the sun, sudden sitting, or when there are tiny cracks inside.
• Material issues: If the wall of the gas spring cylinder is too thin, it may crack after countless cycles, causing components to pop out. Although it usually does not explode, there will be a noise.

According to a spot check by the State Administration for Market Regulation, the unqualified rate of office chairs reached 23.3% in 2020, with 17 batches being swivel chairs. The main problems were that the gas springs did not meet the high- and low-temperature resistance standards and lacked explosion-proof steel plates. Over the past few decades, more than 40 similar tragedies have occurred in China. For example, in 2013, Ms. Liu in Fujian Province was sitting on a swivel chair to dry her hair when the chair suddenly exploded. A steel tube about two centimeters in diameter shot out, penetrating her lower body. Fragments of various shapes were removed from her abdomen, with several pieces of metal debris remaining in her intestines alone.

Preventive measures:

• Choose products from genuine manufacturers, with a recommended price of over 200 yuan.
• Check the smoothness of the gas spring's height adjustment and ensure that a explosion-proof steel plate with a thickness of ≥2 millimeters is installed between the seat cushion and the gas spring.
• If the chair starts to make a hissing sound or shakes unsteadily, it may be a sign that the gas spring is about to fail, and prompt action is required.