Compressed Gas Safety

1. Compressed Gas Safety University of Nebraska EHS Lab Safety Colloquium Series Initiative

2. The information and recommendations contained herein have been compiled from sources believed to be reliable and represent the current opinion on the subject. No warranty guarantee or representation is made by Linweld Inc. as to the correctness or sufficiency of any information contained herein and Linweld Inc. assumes no responsibility therewith. The content in this document is not to be construed as legal advice or the final authority regarding OSHA, EPA, DOT or any other government agencies.

3. When it comes to handling compressed gas cylinders and cryogenics; there are only three potential problems. The Containers, The Contents And The Pressure. Other Than That - There Is No Problem!

4. The Containers

5. Gas Packs

6. Gas Packs

7. Let’s Talk About The Container Handling Compressed Gas Cylinders • Never use cylinders as rollers. • Never lift a cylinder by the cap. • Never move or transfer cylinders without their caps. • Never allow cylinders to be exposed to flame or extreme temperatures. • Never tamper with valves.

8. Cylinder Securement • All compressed gas cylinders MUST be secured from falling at ALL times. • Use a chain or other substantial restraint devices whether or not the cylinders are in storage or in use. 29CFR 1910.101(b) & CGA 3.7.4

9. Visually Inspect All Cylinders • Watch for asymmetrical ice patches on the side of the cylinder. • Watch for excessive ice build up on the pressure relief valves. • Arc burns, excessive heat, corrosion and gouges are a few things that can weaken the walls of a cylinder.

10. Protect Valves • Use caps on all cylinders that are able to receive a cap except when connected for use. • Any cracked or dented caps should be brought to the attention of your Linweld Representative. 29CFR 1910.101(a) & CGA 3.4.1

11. Gas Regulators • Regulators are designed to reduce compressed gas pressures to usable pressures. • Regulators come in high & low pressure designs. • Incorrectly exchanging or interchanging regulators can have catastrophic consequences.

12. Gas Regulators • Compressed Gas Regulators are sophisticated and exact metering devices that are required to be used and maintained according to manufacturer recommendations.

13. Gas Regulators The internal working parts of the regulator are precision units. Only qualified technicians should clean or repair a regulator The low pressure gauge indicates the delivery pressure to the hoses & torch The High pressure gauge Indicates the pressure from tank The inlet connections - More just right & left hand thread regulators and connectors are specific to their application. Keep free of oil, grease, & dirt The Pressure adjusting screw turning clockwise allows the gas to flow turning counter clockwise reduces or stops the gas flow

14. Gas Regulators Potential Hazards Interchanging gas regulators has several potentially hazardous outcomes. • The density and the viscosity of various gases change their flows through flow meters. Thus interchanging flow meters between different gases may result in inaccurate readings. The 02 flow meter is not accurate with Helium, or with air.

15. Gas Regulators Potential Hazards Interchanging gas regulators has several potentially hazardous outcomes. • Different gases have different effects with the internal components of the various regulators. Some gases can deteriorate the diaphragms and other working parts.

16. Gas RegulatorsHandling & Use • Regulators are gas specific and not • necessarily interchangeable! • Always make sure that • the regulator and valve • fittings are compatible. • Never use adapters beyond • manufacturers recommen- • dation.

17. Gas RegulatorsHandling & Use • After the regulator is attached, the • cylinder valve should be • opened just enough to • indicate pressure on • the regulator gauge • (no more than one full • turn) and all the con- • nections checked with • a soap solution for leaks.

18. Gas Regulators Potential Hazards Interchanging gas regulators has several potentially hazardous outcomes. • Oxidizing, Flammable, Toxic, Corrosive and Strong Oxidizing gasses are incompatible and auto-reactive. Even trace amounts in the regulators or gas lines could have potentially catastrophic results.

19. Gas Regulators Potential Hazards • Further information can be found in ANSI/CGA V-1-1994 ‘Standard for Compressed Gas Cylinder Valve Outlet and Inlet Connections”. • UNL SOP http://ehs.unl.edu

20. The Contents Hazardous Material is any material known to create a danger to any person’s health, life, or property through contact, exposure, inhalation, fire, explosion or environmental pollution. All compressed & cryogenic gases are considered Hazardous Materials.

21. The Contents Content Identification All compressed gas cylinders are required to be identified as to their contents. OSHA Required Components Product name Precautionary statement Responsible company Always check the cylinder label; NEVER rely on the colorofacylinderastoitscontents.

22. The Contents - Types of Hazards Toxic Irritation Flammable Sensitization Carcinogenic Explosive Reactive Biological Radioactive Corrosive Teratogenic Mutigenetic

23. The Contents Cryogenic Liquids Gases stored as liquids at temperatures below -130o F. Helium / -452o F Nitrogen /-320o F Argon /-302o F Oxygen /-297o F

24. The Contents Non-Cryogenic Liquids Gases stored as liquids at temperatures above -130o F. Nitrous Oxide / -127o F Carbon Dioxide / -109o F Propane / -44o F Anhydrous Ammonia / -28o F

25. Lack of correct PPE and exposure to Liquid Propane

26. The Contents Low Temperature Hazards • Never allow liquids to contact skin or eyes. • If exposed, warm area with warm water. • Make a medical referral. • Oxygen Displacement • Can cause asphyxiation

27. The Contents Health Hazards Central nervous system • Anoxia • Direct action on neurons Target organ effects • Liver • Kidneys • Blood • Reproductive system

28. The Contents Explosive Hazards Flammable Limits (in Air) 0% 100% LEL UEL TOO LEAN TOO RICH FIRE OR EXPLOSION Acetylene /LEL 2.2% - UEL 82.5% Hydrogen /LEL 4.0% - UEL 74.5% Propane / LEL 2.2% - UEL 9.5%

29. The Contents Oxidizers • Supports combustion. • Do not use near oil or grease. • Never refer to oxygen as “air”. • Liquid oxygen can saturate clothing, making them flammable. • Keep 20ft away or separated by a ½ hour rated fire resistant wall from flammable materials.

30. The Contents Explosive Hazards Fire Triangle & Fire Tetrahedron OXYGEN UNINHIBITED CHEMICAL REACTION HEAT FUEL

31. The Contents Handling & Storage Personal Protective Equipment Gloves Eye Protection Face Protection Clothing and Coverings Atmospheric Monitoring

32. The Contents Hazards Temperature Weight Rapid Vaporization Pressure Oxygen Displacement or Enrichment (CO2 is a vasodilator)

33. The PressureExpansion Rates Besides the contact of cryogenic liquid with human tissue there is the rapid vaporization that must be taken into account.

34. Coffee Cup Illustration • One cup of Liquid Oxygen at an expansion rate of 860:1 will produce 649 cubic feet of gas. • One cup of Liquid Nitrogen at an expansion rate of 696:1 will produce 600 cubic feet of gas. • One cup of Liquid Argon at an expansion rate of 841:1 will produce 512 cubic feet of gas.

35. The PressureAsphyxiation

36. Let’s Talk About The Pressure What does 1/2 pound of Dynamite look like?

37. Cylinder Force - Don’t Make A Rocket, Man. The compression of gases is similar to the compression of a spring, the greater compression the greater the release of the stored energy there is. However, unlike a spring in which the energy is released in the opposite direction that it is compressed. Gases do not have a shape, and when accidentally released; releases its stored energy in all directions. A “K” size nitrogen compressed to 2200 pounds per square inch, has the stored energy equivalent to a half pound of TNT! If there was an uncontrolled release of energy such as a valve being sheared off, or the cylinder failed in some way, you would have a rocket or a bomb. Both are undesirable options. Thanks to Don L Wenzl, LINWELD Specialty Gas Technician

38. Other Safety Concerns

39. Compressed gas streams should never be directed toward any person. CGA 3.3.10 • Federal Standard: compressed air shall not be used for cleaning purposes except where reduced to less than 30 p.s.i. and then only with effective chip guarding and personal protective equipment. 1910.242(b)

40. Always keep the regulator free of oil, grease and other flammable substances • Use the correct regulators for the specific gas service. • Never hammer or use ‘cheater bars’ when connecting or disconnecting regulators or manifold connections. • Never ‘tape’ or attempt to ‘wrap’ any leaking connections.

41. DO NOT change the inlet connection on a regulator in an attempt to use the regulator for a different gas service. • Never stand in front or behind a regulator when opening the cylinder valve. • Identify ‘full’ & ‘empty’ cylinders and maintain proper seperations.

42. The scrapper’s pickup truck on which the Oxygen GP was being transported.

43. The pressure relief devices had been removed and plugged using a threaded cap

44. Cylinder exploded at 12:40 PM while transport vehicle was parked on busy Interstate highway Vehicle Location Cylinder Trajectory

45. The blast blew one individual across 5 lanes of traffic. The other was blown approximately 40 feet. Both men survived

46. Cylinder flew approximately ¼ mile before plunging through the roof of an apartment, severing a main natural gas line and coming to rest in the living space Plywood applied over hole in roof

47. Despite heavy damage, no injuries to apartment tenants were reported

48. Apartment interior

49. Note that the media reported the event as a Butane cylinder explosion

50. Monday the 29th of September, 2003, a fitter with a work van left an E size Oxygen and Acetylene cylinder on the back seat of a Toyota dual cab over the weekend.