Compressed Gas Cylinder Plan
The Compressed Gas Cylinder Plan is designed to help the St Cloud School District comply with the Occupational Safety and Health Administration's (OSHA) Compressed Gases standard (29 CFR 1910.101). This Plan outlines standard operating procedures for the safe use of compressed gas cylinders. Operations involving compressed gas cylinder usage in the schools typically are confined to welding stations, industrial arts shops, and laboratories. However, the St Cloud School District shall compile a compressed gas cylinder inventory to identify all types and applications of compressed gases. A reference compliance checklist can be found in Appendix A. A copy of OSHA's Compressed Gases standard can be found in Appendix D.
This Plan is intended to be non-site-specific and will need to be modified to adapt to specific conditions at each site or school district. In addition, the St Cloud School District is responsible for the implementation, enforcement and updating of their Compressed Gas Cylinder Plan. It is recommended that the Plan be reviewed and updated annually. Actual use of this Plan is limited to Resource Training & Solution? and the St Cloud School District which it represents.
Plan Review and Updated Report
Compressed Gas Management Plan Update Report
Program review and changes are documented below. Documented reviews indicate that the plan continues to meet the needs of the District, or has been modified to do so more effectively.
Date Updates/Notes Reviewer 3/31/16 Added 2014 district compressed gas inventory Wayne Warzecha
The Department of Transportation (DOT) defines compressed gases as follows:
- any material or mixture with a pressure in a container greater than 40 psia (pounds per square inch absolute) at 70°F
- regardless of pressure, any material with an absolute pressure greater than 104 psi at 130°F
- any liquid materials with a vapor pressure greater than 40 psia at 100°
Compressed gas in solution: means a non-liquefied gas that is dissolved in a solvent. Typically the gas is unstable in pure form (e.g. Acetylene).
Flammable gases: means any compressed gas that will burn (e.g. Hydrogen, Acetylene, Propane, Butane).
Acetylene consists of 92.3 percent by weight of carbon and 7.7 percent by weight of hydrogen in chemical combination. Usually an acetylene cylinder is filled with a porous material impregnated with acetone. The dissolved acetylene is typically under a pressure of 250 psi at 70°F (21°C).
Hydrogen is typically in cylinders under a pressure of2000 psi at 70°F (21°C).
Oxygen is typically in steel cylinders under a pressure of 2,200 psi.
Liquefied gas: means a gas that is partially liquid at a temperature of 21.1 °C and pressures between 25 to 2,500 psig (pounds per square inch gauge). The actual pressure on the gauge is related to the vapor pressure exerted by the liquid (e.g. Propane, Anhydrous Ammonia, Carbon dioxide, Chlorine). Standard compressed gases do not liquify at ordinary temperatures and under pressures of 2,000 to 2,500 psig.
Non-flammable gas: means a gas that will not burn but may support combustion (e.g. Oxygen, Chlorine, Anhydrous Ammonia).
Non-liquefied gas: means a gas that is entirely gaseous at a temperature of 21.1 °C (e.g. Hydrogen, Nitrogen, Oxygen, Argon).
Regulator: means a device used to reduce the pressure to a safe level for gas removal. The pressure on the gauge typically refers to the remaining pressure in the cylinder.
Equipment failure, leaks, and improper or unsafe use of compressed gases can present serious hazards to employees, as well as the occupants in the St Cloud School District. Some of the potential hazards associated with compressed gas use include the following.
Flammable gases can burn or cause fire when ignited. Oxygen can form explosive mixtures in certain proportions with acetylene, hydrogen and other combustible (flammable) gases. For example, oxygen and acetylene can produce a high temperature flame (in excess of 3,300°C). In addition, certain flammable gases such as acetylene and hydrogen air mixtures have wide flammable limit ranges (2.5 - 81% and 4.1 - 74.2% in air, respectively). Several flammable gases also have low flash points which can result in explosions when a spark, flame or ignition source is present. In some cases, a liquid gas can reach temperatures above their boiling point at normal atmospheric pressure resulting in a major cylinder failure characterized by flying pieces, a vapor cloud or a "fireball" if flammable. This is commonly referred to as a BLEVE which stands for Boiling Liquid - Expanding Vapor Explosion.
Relative to ignition sources such as an open flame, one must also consider the respective gas densities if released. Gases which are heavier than air can migrate along the floor to an ignition source nearby.
Oxidizing gases such as oxygen may not be flammable itself but can react violently with flammable or other combustible materials.
Inert gases such as nitrogen, argon and helium can displace the oxygen in normal breathing air causing simple asphyxiation.
Exposure to gases may be toxic depending on the type of gas, the dose or exposure level and the route of entry into the body. Many gases have no odor or color. Examples of toxic gases include carbon monoxide and phosgene.
Some gases, such as chlorine, are corrosive in nature acting as an irritant to the skin. Gases with low boiling points such as nitrogen can cause frostbite upon direct skin contact.
A. General Requirements
The following are general handling procedures to be implemented by all St Cloud School District personnel whose job classifications/duties include the use of compressed gas cylinders.
- Order and accept only Department of Transportation (DOT) approved cylinders. DOT specifies testing, filling, safety devices and shipping protocol for compressed gas cylinders. When receiving a cylinder, confirm that the following are present on the cylinder:
- Protective cap
- DOT label
- Gas identification label
- Use cylinders in rotation as received from the supplier.
- When moving cylinders, never drag or drop them. Rolling the cylinder along its bottom edge is possible but not a preferred method. Where possible,- use a hand truck or motorized truck with a strap or chain to secure the cylinder. Do not lift cylinders with slings — carry using a cradle or other suitable platform.
- Never tamper with the safety devices installed on the cylinder.
- Never subject a cylinder to a temperature over 125°F or below -20°F (unless special stainless steel cylinders are present).
- Never permit a flame to come in contact with the cylinder or its parts.
- Always stand off to the side of the cylinder valve when opening.
- Bond and ground all cylinders containing compressed gases.
- Wear safety glasses, goggles or face shield when working with compressed gases. Use of respirators depends on the toxicity of the gas (refer to the St Cloud School District's Respiratory Protection Plan).
- Use connections for the appropriate type of gas, usually identified by a Compressed Gas Association (CGA) number.
- Never use pure oxygen in place of compressed air for dusting purposes or to power pneumatic tools.
- Never use oil or grease as a lubricant on oxygen-containing cylinders. All refilling will be done by a gas supplier or other outside vendor.
- Conduct routine leak tests as specified by the manufacturer or in the Material Safety Data Sheet. Remove all continuously leaking gas cylinders, especially flammable gases, to the outside or to another safe location for venting. The area immediately around a venting cylinder shall be secured.
- Confirm any special handling requirements for any new types of gases used from the manufacturer or supplier.
All cylinders must be code stamped with the date made, date of each hydrostatic test (most cylinders for many gases are required to be tested every five years), a label identifying the gas type or common name, a DOT label if the cylinder is shipped by interstate carrier and a hazard/warning label. All cylinder labels shall be left intact and unable to be readily removed. Although there is no industry standard for color coding currently, some gas cylinders are color-coded.
All empty cylinders shall be clearly labeled as empty. Ideally, a cylinder should not be completely drained to prevent potential backflow of air and moisture into the cylinder.
C. Hoses and Piping System
Oxygen hoses are commonly green in color, acetylene (fuel) red in color and inert gases and air hoses are black in color. Connections for oxygen and acetylene are typically marked as STD-OXY and STD-ACET, respectively. The following are standard precautions with hose systems.
- Avoid long lengths of hose which tend to create problems when purging and can become easily tangled or kinked.
- Route or suspend hose overhead to avoid running over by forklifts or pedestrians.
- Periodically test hose and connections for leaks as per the manufacturer's recommendations.
- Immediately repair all leaks.
- Avoid direct hose contact with flying sparks or hot slag.
- Check-valves should be present at the torch end to prevent the backflow of gases.
If piping distribution systems are used, they should be color coded or clearly labeled as to their type of gas carried. A backflow check-valve or seal should exist at every point where gas is withdrawn.
Regulators should always be used if available to control the gas discharge rate. Standard procedures associated with compressed gas cylinder regulators include:
- Always crack the cylinder valve open momentarily before attaching the regulator to remove any debris or dust.
- Only use approved or listed (Underwriters Laboratories, Inc. or Factory Mutual) regulators designed or intended for the gas in use.
- Each regulator should be equipped with a high pressure (contents) gauge and a low pressure (working) gauge.
- High pressure oxygen gauges should have safety vent covers to protect the operator from broken glass in case of an internal explosion.
- Each oxygen gauge should be marked: "OXYGEN - Use No Oil."
- Never open the cylinder valve until the regulator is drained of any residual gas.
- Never attach an oxygen regulator to another gas or vice-versa (the cylinder valve outlet threads should match up with the regulator).
- Do not use regulators which leak or whose hand(s) do not register properly.
- Follow the manufacturer's recommendations if a manifold system is used to connect more than one cylinder together.
Note: Most liquified gas cylinders pressure (vapor pressure) will remain constant with use as long as some liquid is present and the temperatures do not vary much. To evaluate the remaining amount of gas, the cylinder must be weighed. The tare weight is usually tagged or stamped on the cylinder.
E. Safety Devices
All DOT approved cylinders must have safety devices except:
- Those 12 inches or less in length (exclusive of neck) and with an outside diameter of 4 1/2 inches or less unless they are charged to 1,800 psi or more at 70°F.
- Those charged with non-liquefied gas of 300 psi or less at 70°C.
- Highly toxic or poisonous gases. This is based on the release of the gas itself being more harmful then the potential failure of the cylinder.
Safety or pressure relief devices consist of the following types:
- Safety pressure-relief valve — a spring loaded valve which shuts when the internal pressure returns to a safe value. Used primarily for low-pressure, liquified and flammable gases.
- Rupture disks (also referred to as frangible disks) — used primarily to relieve overpressure in high-pressure cylinders. They are set to burst open at pressures for above those of the gases inside but below the hydrostatic pressure at which cylinders must be tested periodically.
- Fusible metal plugs — a plug which melts at a certain temperature, usually between 157 to 170°F.
- Combination frangible disk/metal plug — the disk will function only after a specific temperature has been reached at which the fusible metal plug melts.
Never tamper with any safety device(s) present.
Always check for leaks — depending on the type of gas, evacuation of an area or facility may be necessary if a leak is present.
The St Cloud School District shall store all compressed gas cylinders in a secure, dry and well ventilated room. Where practical, the room shall be designated for compressed gas cylinders only. The following are standard procedures for storing compressed gas cylinders.
- Never store cylinders near boilers, steam/hot water pipes, flammable materials, or other sources of ignition.
- Always store with the protection cap on if the frequency of use is sporadic.
- Always close the valve when not in use regardless of whether a regulator is present.
- Always secure cylinder to a stable object using a chain, strap or other fastener to prevent knocking the cylinder over.
- Always group similar cylinders together and avoid storing incompatible gases together (e.g. hydrogen and oxygen).
- Always store empty cylinders separate with their valves shut and protective cap on. The purpose of this is to avoid air/moisture being drawn in during ongoing temperature changes.
- Always store cylinders valve side up, especially the flammable gases.
- Oxygen cylinders indoors should not be within 20 feet of cylinders containing flammable gases or other highly combustible materials unless they are separated by a fire restrictive partition/wall at last 5 feet high with a fire rating of at least 30 minutes.
- Corrosive gases should not be stored for more than three months. In addition, all attachments should be removed from the valve outlet when stored if frequency of use is minimal.
All St Cloud School District personnel whose job functions include working with compressed gas cylinders shall receive training prior to any initial use or work assignments and an annual refresher thereafter. This training may be combined with the St Cloud School District's Employee Right-to- Know training program.
Specific topics to be covered during training for employees include:
- Classifications of compressed gases
- Hazards associated with compressed gases
- Standard Operating Procedures
- Regulators and safety devices
- Proper storage procedures
A Compressed Gas Cylinder Training Log can be found in Appendix B.
Appendix A: Compliance Checklist
Appendix B: Training Log
Appendix C: Compressed Gas Inventory
Welding Shop 912 & 914
1 – Argon Compressed
8 – Compressed Gas N.O.S.
3 – Oxygen
1 – Acetylene Dissolved
1 – Acetylene
1 – Oxygen
Grounds-Keeper Garage (small tanks)
1 – Acetylene
1 – Oxygen
Outside Storage Rooms for Welding
4 – Acetylene Dissolved
6 – Oxygen
Welding Classroom Booths (Room 10)
11 – Compressed Gas N.O.S.
Auto Shop (Room 9)
1 – Oxygen Compressed
1 – Argon Compressed
1 – Compressed Gas N.O.S.
Grounds-Keeping – Room 179
1 – Oxygen Compressed
1 – Acetylene Dissolved
Appendix D: OSHA Standard
CFR 1910.101 - Compressed Gases (general requirements)
CFR 1910.102 - Acetylene
CFR 1910.103 - Hydrogen
CFR 1910.104 - Oxygen
CFR 1910.105 - Nitrous Oxide