Gas cylinders are a convenient way to store and transport gases under pressure. These gases can be used for different purpose including industrial use, extinguishing fires, cooking and heating. The main hazards associated with the use, storage and handling of compressed gas cylinders are: the chemical hazard associated with the cylinder contents (corrosive, toxic, flammable, etc.) and the physical hazards represented by the presence of a high-pressure vessel in a room.
With the phasing out of firewood (coal) and cooking stove, most homes in the urban areas of Nigeria now use gas cylinders as a source of fuel for cooking due to technological advancement and adoption of cleaner technologies, better lifestyle and convenience of cooking.
Cylinders that contain compressed gases or any type of gas have to meet various construction and installation standards and they must come equipped with a variety of safety features. Incidents involving compressed gases can be very fatal due to the highly flammable nature of their contents. Sometimes workers don't recognize the hazards associated with the gases and so they don't take protective measures or they may not appreciate that while the cylinders are heavy, they are also very delicate and hazardous and require very careful handling and storage. Each gas has its own specific hazards, and you have to check your MSDS (Material Safety Data Sheets) to make sure you are following the precautions required to use a particular gas safely.
The hazards of compressed gases vary, but most fall into these general categories:
· Fire (resulting from escape of flammable gasses or fluids)
· Explosion (from the blast or rapid release of compressed gas)
· Release of toxic substances (released gas or fluids)
· Manual handling injuries
· Impact from falling cylinders or valves
Most compressed gases will burn or explode under the right circumstances and, without adequate care and planning could lead to accidents.
Protection against Hazards
The United States OSHA (Occupational Safety and Health Administration) regulations highlight a number of tips to prevent accidents with compressed gas cylinders.
· Identification: Each cylinder should be marked with its identity, so you know which MSDS to check to find out about hazards associated with its use.
· Storage: Compressed gases have to be stored in a dry well-ventilated area at least 20 feet from combustible materials, away from any heat source or electrical wiring, stored on a level fireproof floor where they won't be banged or knocked over, and secured upright by chain, cable, or something similar.
· When cylinders are in storage, valves have to be closed and valve protection caps should be screwed down to the last thread.
· Organize the storage area so that you always go for the cylinders that have been in there longest. Put the newest ones received in the back. Apply the FIFO rule = First IN, First OUT
· Transporting: There's a lot of potential for accidents when you're moving gas cylinders, the safest way to move them is to secure them in an upright position
· Mishandled cylinders may rupture violently, release their hazardous contents or become dangerous projectiles. If a neck of a pressurized cylinder should be accidentally broken off, the energy released would be sufficient to propel the cylinder to over three-quarters of a mile in height like a missile.
Safe Handling and Use Guidelines:
One has to be extremely careful when handling compressed gas cylinders, so they don't come in contact with anything that could create fire or explosion.
· Don't purchase a larger cylinder size than necessary, excess reactant can be a problem for disposal, increases the risk to a larger area if accidentally released and is more difficult to store in a ventilated area if required.
· Before connecting a gas cylinder to equipment make sure that the regulator and equipment are suitable for the type of gas and pressure being used.
· When required, wear suitable safety shoes and other personal protective equipment when handling gas cylinders.
· Fire extinguishing equipment should be readily available when combustible materials can be exposed to welding or cutting operations using compressed cylinder gases
· Do not use gas cylinders for any other purpose than the transport and storage of gas.
· When the cylinder is not in use the valve protection cap must be in place to protect the valve; never transport without the regulator in place
· Never drag, slide or roll the cylinder - get a cylinder cart or truck and use it
· Cylinders should not be hoisted by wrapping slings around them but should be secured in an approved rack or cylinder truck during transportation.
Special precautions are also required when storing cylinders:
· They must be secured at a point approximately 2/3 of its height, using appropriate material.
· As with any hazardous material, you may not store gas cylinders in public hallways or other unprotected areas.
· Cylinders must be secured individually, i.e., one restraint per cylinder.
· Cylinders should be segregated in hazard classes while in storage, at the minimum, oxidizers (such as oxygen) must be separated from flammable gases, and empty cylinders should be isolated from filled cylinders.
· Cylinders shall not be placed where they may be exposed to an electrical arc or sparks, slag, flame, or other heat sources.
· Keep cylinders on the outside of buildings in closed structures where possible.
Before the cylinder is first used the following precautions should be taken:
· Make sure the cylinder is equipped with the correct regulator. Always use the regulator designed for the material in use, and be especially careful that under no circumstances is grease or oil used on regulator or cylinder valves because these substances may cause an adverse, dangerous reaction within the cylinder
· The cylinder should be placed so that the valve handle at the top is easily accessible at all times
· Open the valve slowly and only with the proper regulator in place - the valve should be opened all the way. Never leave a valve half way open - either open it all the way or close it all the way
· The valve should never be left open when equipment is not in use, even when empty; air and moisture may diffuse through an open valve, causing contamination and corrosion within the cylinder
This covers general safety procedures that all employees should be aware; keep your eye out for improperly stored gas cylinders, or gas cylinders that are being used without the proper safety precautions.
A quick note for those people that use gas for cooking:
· Ensure that your gas stove gets serviced once a year
· Every time you change the gas cylinder, look at the regulator and the regulator tubing to ensure that it is still in good condition
· Ensure that the gas stove is switched off properly.
· Teach your children and domestic staff on the dangers of gas cylinders
· If you ever smell gas, DO NOT TRY TO SWITCH A LIGHT OR A TORCH OR A MATCH OR YOUR CELL PHONE. All these things have the potential to cause a spark that will ignite the leaking gas and explode. Instead, leave the house immediately and call for help. If possible, open all windows and doors, switch off the gas cylinder and wait for the technician to come and do it for you.
Remember - the greatest physical hazard represented by the compressed gas cylinder is the tremendous force that may be released if it is knocked over!
Written by O'Reese of En-pact Solutions Limited, 2013