TECHNICAL BULLETIN
RECOMMENDED CHARGING PROCEDURES FOR FIBER REINFORCED HIGH PRESSURE CYLINDERS
1. Visually inspect the cylinder for hydrostatic test date, deep nicks, cuts, high heat exposure, or other potential damage. Refer to Compressed Gas Association pamphlet C-6.2-1988, "Guidelines for Visual Inspection and Requalification of Fiber Reinforced High Pressure Cylinders," for this inspection. If discrepancies are noted, DO NOT REFILL. Do not refill any cylinder which has not been retested for more than three years. Do not refill any cylinder which is more than fifteen years old.
2. It is recommended that the cylinder be placed in a suitable "fragmentation container" prior to filling to prevent personal injury in the event of component failure while recharging. The use of a water bath during filling is not recommended, simply because the composite overwrap is such a good insulator that the water bath has little effect on internal temperature. A water bath by itself is not generally considered to be an effective fragmentation container.
3. Fill the cylinder to the marked service pressure. Pressurization rate has little effect on fiber reinforced cylinders, therefore, no maximum fill rate is specified. Cylinder charging causes a rise in internal cylinder temperature, therefore, the pressure will decrease as the cylinder cools to room temperature. Top off the cylinder to service pressure after cooling.
A. In the case of cylinders to be filled with breathing air: use clean dry air in accordance with CGA Specification G-7.1, Type 1, Grade D or better with a dew point of -65° or lower.
Note: The information contained in this bulletin was obtained from sources believed to be reliable and is based on technical information, experience, and regulations currently available from the Compressed Gas Association, United States Department of Transportation (DOT), and others. It is recommended that readers refer to the United States Code of Federal Regulations Title 49 (49CFR) part 173.302, "Charging of cylinders with non-liquified gases", for detailed charging requirements specified by the DOT.