Inspection period and safety regulations for steel cylinders
The inspection cycle (periodic inspection interval) of gas cylinders varies strictly with cylinder types, filled media and service environments. Safety is the top priority. Cylinders overdue for inspection pose severe safety risks and must never be used!
The following are the inspection cycle regulations for common types of gas cylinders (mainly in accordance with Technical Regulations for the Safety of Gas Cylinders TSG 23-2021):
1.Liquefied Petroleum Gas (LPG) Cylinders (YSP-15, YSP-50 series)
Design Service Life: 8 years
Periodic Inspection Interval:
Cylinders of YSP-35.5 type (commonly known as 15kg cylinders) and smaller sizes: Inspect once every 4 years.
Cylinders of YSP-118 type (commonly known as 50kg cylinders) and larger sizes: Inspect once every 4 years.
Special Note: Cylinders that have reached their design service life may be extended for one additional inspection cycle (maximum 4 more years of service) if they pass a safety assessment. However, the maximum total service life of any LPG cylinder shall not exceed 12 years. Cylinders that have expired or failed inspection must be scrapped.
2.Industrial Gas Cylinders (e.g., oxygen cylinders, nitrogen cylinders, argon cylinders, acetylene cylinders)
Periodic Inspection Interval:
Cylinders containing corrosive gases (e.g., sulfur dioxide, hydrogen sulfide), cylinders for diving respirators, and cylinders frequently in contact with seawater: Inspect once every 2 years.
Cylinders containing general-purpose gases (e.g., air, oxygen, nitrogen, argon, helium, carbon dioxide): Inspect once every 3 years.
Cylinders containing inert gases (e.g., helium, neon, argon, krypton, xenon), high-purity gases, and mixed gases: Inspect once every 5 years.
Dissolved acetylene cylinders: Inspect once every 3 years.
Cryogenic insulated cylinders (dewars): Inspect once every 3 years.
Vehicle-mounted liquefied natural gas (LNG) cylinders: Inspect once every 3 years.
Design Service Life: The design service life of industrial gas cylinders varies (commonly 20 or 30 years) and shall be checked against the cylinder's manufacturing markings. Unlike LPG cylinders, industrial gas cylinders must be scrapped once they reach their design service life and cannot be extended via safety assessment.
3.Vehicle-mounted Compressed Natural Gas (CNG) Cylinders
Periodic Inspection Interval:
Cylinders used in taxis and rental vehicles: Inspect once every 2 years.
Cylinders used in other vehicles (e.g., buses, private cars): Inspect once every 3 years.
Design Service Life: Generally 15 years for metal-lined cylinders, or subject to product standards. Cylinders must be scrapped upon reaching the design service life.
4.Vehicle-mounted Liquefied Petroleum Gas (LPG) Cylinders
Periodic Inspection Interval: Inspect once every 5 years.
Design Service Life: Generally 15 years or subject to product standards. Cylinders must be scrapped upon reaching the design service life.
Key Takeaways
| Cylinder Type | Typical filling medium | Regular inspection period | Design service life | Maturity handling |
| Household LPG Cylinder (≤15kg) | Liquefied Petroleum Gas | every 4 years | 8 years | May be evaluated for one extension (up to a maximum of 12 years) |
| Industrial LPG Cylinder (≥50kg) | Liquefied Petroleum Gas | every 4 years | 8 years | May be evaluated for one extension (up to 12 years) |
| Industrial gas cylinder (corrosive) | Sulfur Dioxide, Hydrogen Sulfide, Ammonia, etc. | every 2 years | Typically 20/30 years | Mandatory scrapping |
| Industrial gas cylinder (general) | Oxygen, Nitrogen, Air, Carbon Dioxide, etc. | every 3 years | Typically 20/30 years | Mandatory scrapping |
| Industrial gas cylinder (inert/high purity) | Helium, Neon, High Purity Nitrogen, Mixture Gas, etc. | every 5 years | Typically 20/30 years | Mandatory scrapping |
| Dissolved acetylene cylinder | Acetylene (Dissolved in Acetone) | every 3 years | Typically 30 years | Mandatory scrapping |
| CNG vehicle cylinder (taxi) | Compressed Natural Gas | every 2 years | Typically 15 years | Mandatory scrapping |
| CNG vehicle cylinder (other vehicles) | Compressed Natural Gas | every 3 years | Typically 15 years | Mandatory scrapping |
| LPG vehicle cylinder | Liquefied Petroleum Gas | every 5 years | Typically 15 years | Mandatory scrapping |