Safety Meeting Compressed Gases Lessons to live by! Don’t mix gases in a cylinder. Don’t refill a cylinder. Don’t try to fix a cylinder leak or a valve. Don’t smoke around CGCs. Do tag leaking cylinders, identifying them and instructing that they be kept away from heat Do close the valve on a leaking cylinder, take it outside, empty it and mark it “MT.” Take a trained and equipped firefighter with you
Specific Compressed Gas Hazards Acetylene – extremely flammable and explosive; safe maximum pressure is 15 pounds per square inch for small-diameter piping systems. Argon – Colorless, odorless, noncombustible inert gas shield in arc welding. Ammonia – flammable; inhalation of high concentrations can kill; PPE is mandatory. Also can cause freeze burns and eye injury. Carbon dioxide - can asphyxiate; can also be toxic in high concentrations when inhaled. Will smother petroleum, coal, and wood fires, but will burn rapidly with magnesium, sodium, potassium, and metal hydrides. Chlorine – explosive when mixed with acetylene and exposed to light; can be explosive when combined with alcohols, ethers, and petroleum products. Will corrode iron and steel when mixed with water. Fluorine – also explosive when mixed with acetylene and exposed to light. Corrosive and poisonous; attacks most materials. Freon – 1,1,1, chlorodifluorothane (22) & Perfluorodimethycyclobutane (12) Clear, water-white liquids, vapors have a mild somewhat ethereal odor; non-flammable used in refrigeration and air-conditioning. May contain chlorine and fluorine. Helium – Colorless, noncombustible, odorless, tasteless gas; pressurized rocket fuel; inflation of balloons. Hydrogen – extremely flammable and explosive. Requires good ventilation, especially in storage. Oxygen – accelerates burning of flammable materials. Can produce spontaneous ignition in combination with other elements and compounds. Nitrogen – Production of ammonia, acrylonitrile, nitrates, nitrides; manufacture of explosives; inert gas for purging and freeze drying food. Nitrous oxide – Supports combustion, can form explosive mixture with air; TLV 50 PPM; Anesthetic in dentistry and surgery, propellant in food aerosols. Neon – Colorless, odorless, tasteless gas; Luminescent electric tubes and photoelectric bulbs high-voltage indicators, lasers. Sulfuric hexafluoride – Colorless odorless gas; TLV 1000 PPM; Gases insulator for electrical equipment and radar wave guides.
Construction Marking of Cylinders and Connections Compressed gas cylinders shall be legibly marked, for the purpose of identifying gas content, with either the chemical or the trade name of the gas. Markings shall be either stencil, stamping or labeling – Located on the shoulder when practical – Not easily removed Color Coding of cylinders: What colors are cylinders to be painted? Answer: There is no color code system for CGC’s, each distributor paints what ever they want. The international standard for oxygen is however green. Fuel gas hose and oxygen hose must be easily distinguished from each other. Different colors or surface texture. A single hose that has more than 1 gas passage will never be used as a connection between torch and gas outlet. Liquefied petroleum gas, such as butane or propane must meet the meet the chemical resistance standard of LP-Gas and bursting pressure of 1,250 psi, and marked every (5) feet with the letters “LPG”. Connection between fuel source and burner shall be with Schedule 80 steel pipe. When not in use cap the headed hose and manifold. Hose couplings cannot be unlocked or disconnected by a straight pull without a rotary motion. Oil and grease must be keep away from cylinders, caps, valves, couplings, regulators, hoses that are designed for oxygen.
Regulator TWO-STAGE REGULATOR Two-stage pressure regulators reduce the cylinder pressure to a working level in two steps. Regulators that reduce the vapor pressure of fuel gas to not more that 20 psi are required for all installations within structures or confined spaces unless the appliance specifically requires a higher pressure. Regulators are required for/where a fuel gas hose is between fuel source and the burner.
SINGLE-STAGE REGULATOR Single-stage pressure regulators reduce the cylinder pressure to the delivery or outlet pressure in one step. The best recommended action is to determine how you intend to use the pressure regulator. Generally a single-stage regulator is good for short duration applications; a two stage regulator is good for long duration applications.
Storage, Handling and Use of Cylinders CGC’c: Stored in areas where they are protected from external heat Flame, intense radiant heat, electric arc, or high temperature steam lines. Cylinders are stored with the valve end up. Inside buildings; Well- protected, well ventilated, dry locations – at least 20 feet from combustible materials Assigned storage spaces are located where they can not be damaged by falling or passing objects and can not be tampered with. Transportation; So that are prevented from creating a hazard by tipping, falling or rolling. Liquified fuel-gas cylinders are stored and transported in a position so that the safety relief device is in direct contact with the vapor space in the cylinder at all times. for short distances cylinders may be tilted and rolled on the bottom edge. close valves before moving or when work is finished or when empty All cylinders designed to accept valve protection (Cap) device - must be installed when the cylinder is not in use or connected for use. Unless CGC’s are secured on a special truck or rack, regulators must be removed and valve protection (Cap) installed. Valve protection devices may not be used for lifting cylinders
General Precautions Cylinders will not be placed where them may become/form part of any electric circuit. Never transfer acetylene from on cylinder to another. Oxygen cylinders will be separated from fuel-gas cylinders or combustible materials. Minimum distance of 20 feet (especially oil and grease) Cylinders shall be kept far enough away from actual welding or cutting operations so that sparks, hot slag, or flames will not reach them. Before installing a regulator turn the valve on then off to remove any dust or debris (only “cracking” the valve) This must be done out side of the working area. The person cracking the valve must stand to one side of the outlet – Do Not stand in front. Open the valve slowly – don’t damage the regulator. Not more then 1 ½ turns. If the valve leaks turn off the valve and remove the cylinder from the work area. (Outdoors) Tag the cylinder and move it outdoors, to an isolated area.