HANDLING HIGH PRESSURE CYLINDERS

1. HANDLING HIGH PRESSURE CYLINDERS

2. Sources • T. Joiner (ed.). 2001. NOAA Diving Manual - Diving for Science and Technology, Fourth Edition. Best Publishing Company, Flagstaff, Arizona. • Bill High, notes from PSI Cylinder Inspection Course • US Code of Federal Regulations Title 49: 172.700

3. Goal of This Training • To increase your safety and the safety of those around you by familiarizing you with the policies and proper procedures for handling and filling cylinders containing high pressure gas

4. Objectives • After completing this training module you will be able to: • Identify the regulating bodies regulating hazardous materials training for handling high pressure cylinders and explain the regulations as they pertain to scientific diving • Define a high pressure cylinder as it relates to diving

5. Objectives • After completing this training module you will be able to: • Identify and explain cylinder markings for steel and aluminum scuba cylinders • List 25 safe handling procedures for high pressure cylinders • Define the parts of a fill station and list procedures for filling high pressure cylinders common to all fill stations

6. Regulation • In the US: • The Department of Transportation (DOT) regulates transport of high pressure cylinders • The Department of Labor, Occupational Safety and Health Administration (OSHA) regulates safety in the workplace

7. Regulation • The Code of Federal Regulations (CFR Title 49: 172.700) mandates employees of companies involved in commerce who handle compressed gas cylinders to receive appropriate safety training. • A new hire should receive this training within 90 days of hiring • Training should be repeated every three years

8. Regulation • Discussions with US DOT have determined that most organizations involved in scientific diving are not involved in commerce and are exempt from the three year retraining updates • Local regulations or standards may re-impose this requirement

9. Regulation • AAUS and NOAA scientific diving standards require all scientific divers to receive hazardous materials training for handling high pressure cylinders

10. High Pressure Cylinders • The capacity of a cylinder is the amount of gas at surface pressure that can be compressed into the cylinder at its rated pressure • This capacity is usually expressed in standard cubic feet or standard liters of gas • Cylinders with capacities from 26 standard cubic feet to over 100 standard cubic feet are used in scuba diving

11. High Pressure Cylinders • Scuba cylinders are generally made of steel or aluminum • Cylinders used in diving fill to working pressures ranging from 1,800 to 3,500 psi (124 to 241 bar) or greater

12. Cylinder Markings • Data describing the cylinder must be clearly stamped on the shoulder of the cylinder Image courtesy Best Publishing

13. Cylinder Markings • The precise manufacturing specifications of cylinders have been dictated by: • The Interstate Commerce Commission (ICC) until 1970 • The Department of Transportation (DOT) after 1970 • The TC/DOT (Transport Canada and DOT) most recently dictates specifications for aluminum cylinders

14. Steel Cylinder Markings Image courtesy Best Publishing

15. Steel Cylinder Markings • DOT (Department of Transportation – may also read ICC if cylinder predates 1970) • 3AA (indicates steel construction) • Service pressure • Serial number • Cylinder manufacturer’s symbol • Hydrostatic test date

16. Steel Cylinder Markings • A plus sign (+) stamped after the hydrostatic test date indicates a steel cylinder can be filled 10% beyond its designated long-term service pressure • This (+) is valid only for the initial five year hydrostatic test period, unless the hydrostatic test facility retests the cylinder to meet the 110% fill requirements

17. Aluminum Cylinder Markings Image courtesy Best Publishing

18. Aluminum Cylinder Markings • DOT (or ICC) • 3AL (indicates aluminum construction) • Service pressure • Serial number • Service volume • Manufacturer • Hydrostatic test date

19. Safe Handling Procedures • Treat all cylinders designed to hold high pressure gas with respect • Do not drop cylinders

20. Safe Handling Procedures • Wear shoes when working around cylinders • Have a clear path to avoid tripping or knocking over cylinders or other equipment

21. Safe Handling Procedures • Cylinders are heavy and awkward; use proper lifting techniques and dollies to minimize the risk of personal injury

22. Safe Handling Procedures • Handle charged cylinders carefully – handling by the valve or body is preferred • handling by straps or backpack may allow the cylinder to slip or drop • Cylinders should be stored at temperatures not to exceed 130o F (54 C)

23. Safe Handling Procedures • Store charged cylinders in an upright position in a cool shady place and away from flammable materials • Secure cylinders properly to prevent falling or rolling Photo courtesy Steve Sellers

24. Safe Handling Procedures • While in transit, cylinders should be secured from rolling • Preferably in a rack in the upright position Photo courtesy Steve Sellers

25. Safe Handling Procedures • Open cylinder valves slowly • Do not put your body in the gas stream • High pressure can force gas through the skin and into the body; bubbles in the circulatory system could result in an embolism • Injuries of this nature are not uncommon, so please keep out of harms way

26. Safe Handling Procedures • Cylinders that appear to be damaged by fire or physical abuse should be removed from service

27. Safe Handling Procedures • Scuba cylinders should receive a visual inspection by a qualified inspector annually • A cylinder with signs of damage or that has been totally emptied, should receive a visual inspection before being put back in service

28. Safe Handling Procedures • Internal inspections, hydrostatic tests, and repair work should be performed only by trained technicians Image courtesy PSI

29. Safe Handling Procedures • Remove cylinder boot frequently to inspect for corrosion • Boots that inhibit rapid draining and drying should not be used because they allow water to remain in contact with the cylinder, forming corrosion

30. Safe Handling Procedures • A cylinder that has been condemned during the visual inspection or hydrostatic testing process may never be returned to service • Condemned cylinders should be made unserviceable (i.e. cut in two, hole drilled in the wall, threads destroyed, etc…)

31. Safe Handling Procedures • Do not use any cylinder that: • Is aluminum and has a rounded bottom • Have the manufacturing codes SP6576, SP6688, or SP890 stamped into the cylinder • Have large dents, bulges, or lines of corrosion • Do not have a proper pressure relief device (burst disc)

32. Safe Handling Procedures • Do not use any cylinder that: • Have manufacturing codes SP6498, E6498, SP7042, or E7042 stamped into the cylinder unless the cylinder is also stamped with the code 3AL • These were special aluminum alloys that were given the 3AL rating at a later date

33. Safe Handling Procedures • Do not totally empty a cylinder without cause • Always try to leave 300 to 500 psi in the cylinder • Empty cylinders should be internally visually inspected by a trained technician prior to re-filling

34. Safe Handling Procedures • Regulators or gauges may fail when a cylinder valve is opened – it is important to stand to the side rather than in the line of discharge to avoid the blast effect in case of failure Photos courtesy Dave Pence

35. Safe Handling Procedures • Do not look directly at the face of any pressure gauge when turning on the cylinder because of the possibility of a blowout Photo courtesy Steve Sellers

36. Fill Stations and Filling Cylinders • Diving cylinders and associated high pressure equipment are manufactured and tested to standards in order to ensure a high degree of safety when they are properly used and maintained

37. Fill Stations and Filling Cylinders • Manufacturing standards and maintenance requirements do not eliminate the possibility of a catastrophic failure that could result in serious injury or death Photo courtesy www.sealancers.org

38. Fill Stations and Filling Cylinders • An 80 cubic foot cylinder filled to 3000 psi (207 bar) has in excess of one million pounds of kinetic energy; sufficient power to blow apart brick walls or destroy vehicles Photo courtesy connected.bc.ca/~baquatics/index.htm

39. Fill Stations and Filling Cylinders • 90% of all cylinder explosions occur during the filling process • Operator error has been linked to many of these incidents Photo courtesy www.sealancers.org

40. Fill Stations and Filling Cylinders • Properly trained and attentive operators reduce their risk of being involved in a catastrophic incident • Be familiar with the equipment you are working with and follow inspection requirements and safe operating procedures

41. Fill Stations and Filling Cylinders • A fill station consists of a source of high pressure gas, high pressure lines called whips that connect the gas source to the cylinders being filled, and valves and gauges to control and monitor the filling process

42. Fill Stations and Filling Cylinders • Fill stations come in a wide variety of configurations, the specifics of operating a given system are beyond the scope of this presentation and require additional training

43. Fill Stations and Filling Cylinders • Compressor basics: • High pressure compressors capable of producing breathing grade gas intake air, compress the air through a series of stages to increase the pressure, and filter the gas to remove impurities and excess moisture Photos courtesy Bauerair.com

44. Fill Stations and Filling Cylinders • Compressor basics: • Each compressor has its own operational and maintenance requirements, but items common to all units include: • Checking oil levels prior to startup • Monitoring compressor hours and filter life • Monitoring the compressor intake to assure a proper air source, and monitoring stage pressures • Keeping a log of regular maintenance and adhering to a maintenance schedule

45. Fill Stations and Filling Cylinders • Storage banks take two forms: • A series of cylinders connected by manifold to produce a desired storage capacity • Or a single large storage cylinder such as a recycled submarine ballast tank • Cylinders connected by manifold have the advantage of allowing cascade filling • A single large storage cylinder can offer the advantage of not requiring periodic hydrostatic testing

46. Fill Stations and Filling Cylinders • Storage banks have specific pressure limitations and are secured to prevent them from falling • Banked pressures of 4,500 psi (310 bar) are common Photo courtesy Steve Sellers

47. Fill Stations and Filling Cylinders • Cascade filling involves equalizing the pressure in the cylinder being filled with the pressure in a single cylinder in a series of storage cylinders, moving to the next cylinder in the series and repeating the process until the desired pressure is reached • Cascade filling is the most economical use of banked gas

48. Fill Stations and Filling Cylinders • Fill station valves can be of a metering or ball valve design • A metering valve provides for slow and controlled pressure adjustments • A ball valve is either open or closed Photos courtesy Global Mfg. Corp. Metering Valve Ball Valve

49. Fill Stations and Filling Cylinders • Caution should be taken when using fill panels employing ball valves, a rapid pressure spike can increase the risk of a fire in the presence of gases with high oxygen content Photo courtesy Steve Sellers

50. Fill Stations and Filling Cylinders • High pressure lines: • Pipes and hoses that carry high pressure gas should be secured approximately every two feet and regularly inspected Photo courtesy Steve Sellers