• Visual Inspection: We strip the bottle of all stickers and remove the valve to conduct a deep internal and external inspection for signs of corrosion, dents, or thread wear.
• Hydrostatic Pressure Test: The cylinder is filled with water (an incompressible liquid) and pressurised to approximately 1.5 times its normal working pressure.
• Expansion Measurement: We precisely measure how much the bottle expands under this pressure. To pass, it must return to its original size within a strict 5% tolerance, proving the material hasn't weakened over time.
• Valve Servicing: As part of the service, the valve is typically stripped, cleaned, and fitted with new seals to ensure it operates smoothly and safely. 

• Safety First: Compressed air at 300 bar holds massive energy. Testing identifies invisible "fatigue" or internal rust that could lead to a catastrophic failure.
• Legal & Filling Requirements: Most commercial filling stations will refuse to fill a cylinder that is "out of test".
• Standard Intervals:
  • Surface-use-only bottles (fitted with a gauge and bleed screw) typically require testing every 5 years.
  • Diving-valve bottles (without a dedicated gauge) require a test or visual inspection every 2.5 years.

Bottle Test Cost - £65 if just basic seals etc need replacing. Any more indepth work gauges etc will incur extar charges at price we are charged.