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Presented by: Wajeeha Kiran 2008-chem-51 Ambreen Akram 2008-chem-17 Sana Arif 2008-chem-47 Aiman Fatima 2008-chem43 Safe Use of Cylinder Gases

Synopsis  Introduction to Gas Cylinder Safety  Main causes of Accidents  Main Hazards  Rules for Safe Working with Gas Cylinders  Gas Regulators  Flashback Arrestors  Hoses, Piping, Blow Pipes and Torches  Acetylene –unique properties  Handling Gas Cylinders

Cont’d…….  Transporting Gas Cylinders  Safe Storage  Cylinder Incident Response  Gas Cylinders Hazards in Your Workplace  Conclusions

Introduction  Compressed gases used in a variety of industrial and laboratory situations  Compressed gases present a unique hazard. Depending on the particular gas, there is a potential for simultaneous exposure to both mechanical and chemical hazards  Gases can be: o Flammable or combustible o Explosive o Corrosive o Poisonous o Inert

Common Industrial Gases  Oxidants support combustion e.g. air & oxygen  Inerts do not generally react with other materials e.g. nitrogen, argon, helium  Flammables when mixed with oxidant and ignition source will burn e.g. acetylene, hydrogen, propane  Toxics that is toxic in small concentrations e.g. ammonia, chlorine, carbon dioxide  Corrosives react with materials causing reactions e.g. chlorine, sulphur dioxide

Main Causes of Accidents  Inadequate training and supervision  Poor installation  Poor maintenance  Faulty equipment or design  Poor handling  Poor storage

Main Hazards  Impact from the blast of a gas cylinder explosion or rapid release of compressed gas  Contact with the released gas or fluid(such as chlorine)  Fire resulting from the escape of flammable gas or fluids such as LPG  Impact from falling cylinder

Safe Working with Cylinders Identification and Properties  Read the label to see what gas you are dealing with and double check that the cylinder/gas is right for the intended use  If the labeling on a cylinder becomes unclear or an attached tag is defaced to the point the contents cannot be identified, the cylinder should be marked "contents unknown" and returned directly to the manufacturer

Cont’d……  Never rely on the color of the cylinder for identification. Color coding is not reliable because cylinder colors may vary with the supplier. Additionally, labels on caps have little value because caps are interchangeable  If there is a mismatch between the colour of a cylinder and the label. Do not use, contact the supplier immediately  Know the properties of the gas (read Material Safety Data Sheets available from your Supervisor)  The cylinder’s contents should be identified at all times as well as the cylinder status (full, empty or in service)

Cont’d…… Daily Inspection  Cylinders should be inspected daily and prior to each use for corrosion, leaks, cracks, etc.  Inspection should include the cylinder, piping, safety relief devices, valves, protection caps and stems.  Leaking regulators, cylinder valves or other equipment should be taken out of service.

Cont’d…….  Maintenance of cylinders and their valves or relief devices shall be performed only by trained personnel.  An emergency response plan shall be developed and implemented wherever compressed gas cylinders are used, handled or stored.  Never smoke around compressed gas cylinders.

Gas Cylinder 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 connections checked with a soap solution for leaks.

Cont’d……  Before a regulator is removed from a cylinder, the cylinder valve shall be closed and the regulator relieved of gas pressure. The valve cap shall be replaced, the cylinder clearly marked as "empty," and returned to a storage area for pickup by the supplier  Regulators, gauges, hoses and other apparatus shall not be used on gas cylinders having different chemical properties  Valve outlet thread size is different for different products but the same products from different gas suppliers will have the same thread

Gas Cylinder Regulators A regulator is a device that receives gas at a high pressure and reduces it to a much lower working pressure  Precision instruments must be handled with care to avoid damage  Equipment should display the relevant European/British Standard no.and the pressures up to which it can operate  Leave the pressure adjustment knob fully out when the regulator is not in use

Flashback Arrestors  Flashback is the result of mixture of fuel gas and oxygen burning within the hose, flame travels and burns its way towards the gas source at great speed, can result in force of explosion in either cylinder  Flashback arrestors must be fitted on both oxygen and fuel gas regulators  If flashback arrestor is dropped/damaged replace immediately  Flashback arrestors should only be used with the gas they are labelled for and the pressure they are designed for

Common reasons for flashback  incorrect purging of hose  incorrect gas pressure  incorrect nozzle  damaged torch valves  gas passages blocked within the torch

Hoses  Correct hose bore size, pressure rating, length and colour coding are essential for safety BS EN 559 Colours  Blue – oxygen, Red - acetylene and other fuel gases(except LPG)  Black – inert and non combustible gases  Orange – Liquified Petroleum Gas  Never use equipment while hoses are wrapped around the cylinders or trolley  Length of hose should be suitable for the task  Keep hoses in good condition

Cont’d…….  Examine the hose for cracks, deterioration, damage and test the hose for leaks before use  Do not repair hoses unless you have the skill  Purge hose thoroughly before lighting torch  Do not use copper piping with acetylene hoses as it is potentially explosive  Protect hosing from heat, oil, grease or mechanical damage

Piping  Distribution lines and their outlets should be clearly labeled as to the type of gas contained  Piping systems should be inspected for leaks on a regular basis  Special attention should be given to fittings as well as possible cracks that may have developed

Blow Pipes and Torches  Leaks are a serious hazard as they are closest to the operator  Always check condition before use, ensure tip is free of obstruction  Signs of heat damage around the blow pipe or torch may indicate the equipment has suffered internal damage and is leaking and should be replaced immediately  Replace blow pipe or torch if o Broken bent or loose gas control valve o Bent cutter tube o Broken of bent cutting oxygen lever

Acetylene  Acetylene has unique properties  Acetylene gas under excess pressure becomes unstable  Cylinders should never be subject to intense heat or physical impact as the rise in temperature and pressure may cause the acetylene to thermally decompose  The cylinder may appear normal but if it is moved it may detonate with fatal consequences

Handling Gas Cylinders  Wear gloves, protective footwear, eye protection  Correct way to move cylinders is to: keep upright, secure and with valves uppermost  Use mechanical aids such as a trolley where reasonably practicable  All personnel involved should have completed manual handling training  Never transport cylinder with valve and pressure regulator attached or with the valve open  Never attempt to catch a falling cylinder just get out of the way  Never lift a cylinder by its cap, valve or guard

Transporting Cylinders  If possible carry in open vehicles or trailers  If they must be carried in closed vans/cars ensure good ventilation at all times  If the load compartment is not separated from the driver do not carry toxic gas cylinders (those with a toxic gas label and having yellow as a colour on the cylinder)  Ensure gas cylinders are clearly labelled to show contents and associated hazards  Fit suitable protective valve caps and covers to cylinders

Cont’d…….  Disconnect hoses and regulators from cylinders  Carry propane cylinders upright and do not carry flammable gas cylinders in the same compartment as toxic gas cylinders  Do not smoke while carrying cylinders inside vans/cars  Unload the cylinders as soon as possible and move to a well ventilated storage area  If you are involved in an accident advise, any emergency services involved what gas cylinders are being carried

Safe Storage  I t is best to store gas cylinders in the open and on concrete in a fenced compound with some weather protection  In storage areas oxygen cylinders must be stored at least 3 metres away from a fire wall from fuel gases  Protect gas cylinders from external heat sources which may adversely affect their mechanical integrity

Cont’d…….  Acetylene and propane must never be stacked horizontally either in storage or in use  Storage areas with gas cylinders must have more than one exit  Cylinders should be located away from any heat/source of ignition and if possible away from the fire exits, elevators, walkways, building egresses, unprotected platform edges, or in locations where heavy moving objects may strike or fall on them

Cont’d……  Storage arrangements should be clearly described in the emergency plan  Storage area must have good housekeeping and adequate warning signs with fire fighting equipment as necessary

Cylinder Incident Response If a cylinder is leaking but the leak has not ignited and it is safe to do so having considered the gases specific properties:  Eliminate all sources of ignition  Ensure the valve is closed but do not over-tighten it  Put the cylinder in a safe place that is well ventilated keep it upright  Mark the cylinder as faulty and not to be used

Cont’d…….  Warn everyone in the area of the gas leak  Inform the supplier  Ensure the work area is thoroughly ventilated before continuing with any work  If a hydrogen cylinder is involved be aware that hydrogen burns with an invisible flame so seek expert assistance

Cont’d……. If a flashback has occurred:  Close both blowpipe valves oxygen first  Close both cylinder valves  Check the temperature of the acetylene cylinder for thermal decomposition  Check the blowpipe has not overheated  Check the nozzle is not damaged  Open both blowpipe valves oxygen first to vent the system  Unwind the pressure adjustment screw on each pressure regulator  Before starting up again, check the integrity of the whole system

Cont’d……  Nature of hazard will determine procedure to be applied  Call fire brigade  Use large quantities of water to cool the cylinders if safe to do so (do not aim high pressure water direct at the cylinders) from a safe location and await the arrival of trained emergency personnel (Emergency plan training should address)

Cont’d…….  Remove any cylinders not involved in fire to safe place, ensure valves are closed if safe to do so  Inform gas supplier,  If cylinder contents are unknown, treat as acetylene

Conclusions  Compressed gases present a unique hazard. Depending on the particular gas, there is a potential for simultaneous exposure to both mechanical and chemical hazards  Inadequate training and supervision o poor installation o poor maintenance o faulty equipment or design o poor handling o poor storage o inadequately ventilated working conditions

Cont’d…….  When working with compressed gases you need to know the properties of the gas, safe use procedures and what to do when things go wrong  For detailed use of individual gases you should now review the relevant Material Safety data Sheet (MSDS) for each gas used on your site Always Treat Gas Cylinders with Respect!!! & they will respect u in return!!!!!

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