NGI-H2S Awareness


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  • Explain the longer one is exposed to H 2 S the more susceptible the individual becomes Explain the more frequent a person is exposed to H 2 S the more susceptible the individual becomes. Explain the higher the intensity of H 2 S the greater the hazard. Remind candidates of the concentrations likely to do damage . Explain that every person has different tolerance levels to H 2 S. This can prove fatal .
  • SUMMARY OF COURSE Ensure candidates have understood to this point before proceeding.
  • NGI-H2S Awareness

    2. 2. INTRODUCTION <ul><li>All hydrocarbon bearing reservoirs encountered in the South Pars field contain H2S </li></ul><ul><li>There is therefore a major safety concern during First gas, production ,and maintenance operations performed in the Assaluyeh Plant </li></ul>
    3. 3. TOPIC COVERED <ul><li>H2S Names </li></ul><ul><li>H2S Sources </li></ul><ul><li>H2S Properties </li></ul><ul><li>H2S Effects </li></ul><ul><li>H2S Presence, identification </li></ul><ul><li>H2S Measurements </li></ul><ul><li>Hazard Control </li></ul><ul><li>First aid and rescue operations </li></ul>
    4. 4. H2S IS ALSO KNOWN AS <ul><li>Sulphurated hydrogen </li></ul><ul><li>Sour gas </li></ul><ul><li>Rotten egg gas </li></ul><ul><li>Swamp gas </li></ul><ul><li>Sour gas </li></ul><ul><li>Sewer gas </li></ul><ul><li>Stink damp </li></ul><ul><li>Hydrosulphuric acid </li></ul>
    5. 5. It can be a friend, as in sulfurous hot springs, IT HEALS BROUNCHI Is the H 2 S gas is friend or foe ?
    6. 6. When H 2 S reach to dangerous concentration LEADS TO FATAL Hydrogen Sulphide , a Chemical Combination of : H H S H 2 S
    7. 7. H 2 S is also found on earth, resulting from the decay organic matter containing sulphur. In Volcanic activities, it often escapes from earth fissures, mixed with other gases
    8. 8. It also found in natural gas, many type of crude and oil fields It also found in Industry as a result of chemical process and by products of crude oil distillation. It always found in refinery.
    10. 10. <ul><li>H2S is colorless (no visible sign of H2S to warn you of its presence) </li></ul>COLOUR and ODOR Smell often described as rotten eggs
    11. 11. <ul><li>Heavier than air: Specific gravity= 1.189 </li></ul><ul><li>Therefore </li></ul><ul><li>H2S will collect in low areas such as, well cellars, open drain ditches and excavations. </li></ul><ul><li>It has been noticed, however, that H2S could also be swept along with the produced gas and be present on high spots </li></ul>WEIGHT
    12. 12. <ul><li>BOILING and MELTING </li></ul><ul><li>Boiling point - 60.3 C (- 76.5 F), </li></ul><ul><li>Melting point - 82.9 C (- 117.2 F) </li></ul><ul><li>So in its natural state we see it as </li></ul><ul><li>GAS </li></ul>
    13. 13. <ul><li>H2S SOLUBILITY </li></ul><ul><li>Soluble in both water, 4 volume gas in 1 volume water at 0 degree Celsius (Produce irritable gas) and liquid hydrocarbons </li></ul>This gas can be released when the liquid is agitated, such as when wading through water in excavations.
    14. 14. Porous matter such as iron sulphides and oxides and muddy residues, absorbs H 2 S in large quantities. When disturbed or when temp. gets higher, H 2 S gas will form. Many incidents and accidents could be avoided if everybody would remember the fact when the equipment is opened.
    15. 15. <ul><li>EXPLOSIVE </li></ul><ul><li>Forms an explosive mixture with a concentration between 4.3% and 46% by volume </li></ul><ul><li>Auto ignition occurs at 500 F (260 C) which is a very low ignition temperature </li></ul>
    16. 16. LEL and UEL 5 Too much Upper Explosive Limit Explosive Lower Explosive Limit Too little % Explosive Limit EXPLOSIVE 0% 4.3% 46%
    17. 17. <ul><li>BURNING </li></ul><ul><li>Burns with a blue flame and produces Sulphur Dioxide (SO2), less toxic than H2S but very irritating to eyes and lungs and may cause serious injury </li></ul>
    18. 18. Effect of H2S on Equipment <ul><li>H2S combines with moisture in the air to form corrosive acid which eats away at pipes and valves. It cause a form of hydrogen embrittlement known as sulfide stress cracking </li></ul>
    19. 19. IMPORTANT <ul><li>H2S is extremely toxic </li></ul><ul><li>and will be present in high levels in our site. </li></ul><ul><li>UP TO 8000 ppm </li></ul>
    20. 20. H2S EFFECTS ON HUMAN BEINGS <ul><li>Extremely toxic (almost as toxic as Hydrogen Cyanide) and 5 to 6 times as toxic as Carbon Monoxide. </li></ul><ul><li>H2S can only be smelt at low concentrations (1-50 ppm). Beyond 50ppm, the nerve endings are destroyed, you are no longer able to smell anything after about 15 minutes exposure. </li></ul><ul><li>Therefore, </li></ul><ul><li>DO NOT DEPEND ON SMELL TO DETECT H2S </li></ul>
    21. 21. H 2 S is worst when it reaches certain concentrations, as its paralyses the olfactory nerves H 2 S is dangerous in its action on the human body than in causing accidents by ignition and explosion.
    22. 22. H2S Measuring units In dealing with H2S several units may be used for measuring its concentration The most common unit used in the oil and gas industry is the ppm (part per million) 0.0001 volume % = 1ppm OR 10,000 ppm = 1%
    23. 23. TLV-TWA The threshold limit value-time weighted average, TLV-TWA Is the average airborne concentration to which a worker may be exposed for 8 hours per day without any adverse health effects. For Hydrogen Sulphide this value is 5 ppm. The short term exposure limit or STEL is the maximum concentration to which a worker may be exposed for a maximum period of 15 minutes, for hydrogen Sulphide this value is 10 ppm
    24. 24. Duration The way in which H 2 S affects you depends on the following: Frequency intensity Susceptibility The length of time the individual is exposed How often the individual has been exposed The concentration of exposure The individual’s physiological make-up
    25. 25. CONCENTRATION Strong unpleasant odor 27 ppm Immediate respiratory arrest, loss of consciousness, followed by death 1000 ppm Loss of consciousness(approx.20 min), Make conjunctivitis and respiratory tract irritation 300 ppm Lose sense of smell Coughing, Eye pain and Drowsiness 100 ppm 15 min STEL 10 ppm 8 hr.T W A Beginning eye Irritation 5 ppm Smell of rotten egg 1 ppm EFFECTS H2S ppm
    26. 26. Symptoms of Exposure <ul><li>Eye Irritation </li></ul><ul><li>Sickness </li></ul><ul><li>Dizziness </li></ul><ul><li>Choking </li></ul><ul><li>Lack of Muscle control </li></ul>
    28. 28. TECHNICAL PREVENTION AND CONTROL <ul><li>Permit to Work (Risk Assessment) </li></ul><ul><li>(Safe systems of work) </li></ul><ul><li>Identification of Hazardous Areas </li></ul><ul><li>Measurement of Contaminates </li></ul><ul><li>Personnel Training </li></ul>
    29. 30. SAFE WORKING PRACTICES <ul><li>Check the wind direction </li></ul><ul><li>Monitor your working area by gas detectors </li></ul><ul><li>Know at least two escape routes from your workplace </li></ul><ul><li>Know the location of all emergency equipment </li></ul><ul><li>Ensure your emergency training is up to date </li></ul><ul><li>Carry a personal H2S monitor at every opportunity </li></ul>
    30. 31. <ul><li>No smoking </li></ul><ul><li>No naked flames </li></ul><ul><li>No mobile phones </li></ul><ul><li>Never work alone, ensure that at least one other person knows your location </li></ul><ul><li>Know the companies emergency procedures </li></ul><ul><li>Remain vigilant and observe all audio or visual alarms </li></ul><ul><li>All electrical equipment must be approved and intrinsically safe </li></ul><ul><li>You should be aware of safety equipment locations </li></ul><ul><li>You should be aware of escape set locations </li></ul>
    31. 32. Types of Measurement Equipment <ul><li>Fixed Equipment </li></ul><ul><li>Portable Equipment </li></ul>
    32. 33. <ul><li>Fixed Detectors Are Installed Around The Site And Emit an Audible Alarm And sometimes flashing Lights When Gas Levels Are Exceeded. </li></ul>Fixed Equipment This type of equipment gives a continuous measurement in hazardous areas
    33. 34. Portable/Personal Equipment Portable Alarms Are Carried to Any Area in Which Gas Levels Are Required to be measured For Reasons of Personal or Plant Safety .
    34. 35. Portable Detectors usage
    35. 37. You must leave the area and report your findings to your Supervisor & the HSE OFFICE AFTER USING GAS DETECTION EQUIPMENT If gas levels are too high
    36. 38. Emergency and First Aid <ul><li>If we see any person we think may have been affected by H2S, we must help him, </li></ul><ul><li>BUT </li></ul>
    37. 39. Before attempting to rescue a person, You must consider your own safety Avoid delays in the rescue. Response must be immediate if a worker is overcome Remember that time is the most important factor for First Aid you can save a life within a few minutes REMEMBER RESCUE SHALL NOT BE ATTEMPTED UNLESS GAS LEVELS ARE ACCEPTABLE
    38. 40. Emergency Operations <ul><li>In the event of a release of gas from other areas, personnel will take the following actions: </li></ul><ul><li>Shut off all machinery and tools </li></ul><ul><li>Quickly move upwind or crosswind, away from the leakage of gas </li></ul><ul><li>Avoid inhaling, while seeking an area for fresh air. </li></ul><ul><li>Get out of the contaminated area. </li></ul><ul><li>Do not attempt to rescue a worker . </li></ul><ul><li>Never enter a suspected, contaminated area without Breathing apparatus to rescue a co-worker, or for any other reason. </li></ul><ul><li>Evacuate the area in an upwind direction, using the windsocks, flag or existing flare stacks to indicate the wind direction. </li></ul><ul><li>Remember H2S is heavier than air and will gather in low level areas. </li></ul>
    39. 41. <ul><li>10- Sound the Alarm. </li></ul><ul><li>11- Report to your Supervisor and the HSE Office If using a radio repeat THIS IS AN EMERGENCY two or three times to clear the airways and to gain attention. </li></ul><ul><li>12- Calmly state what has happened, the location of the leak and any visible danger to people in the immediate area. </li></ul><ul><li>Have the receiver of your message alert the Project Superintendent and field safety office. </li></ul><ul><li>13- Alert the local Fire Department, Police and other Emergency Response Teams . </li></ul>
    40. 42. <ul><li>14- Get medical aid for workers exposed to H2S. Immediately wash off skin, hands and affected areas with plenty of water and wash out eyes for at least 15 minutes. </li></ul><ul><li>15- If other crews are nearby alert them by radio or by signaling them, keeping a clear distance up wind from the hazard area. </li></ul><ul><li>NOTE: It may be necessary for the company to assist in alerting the general area for evacuation. </li></ul><ul><li>16- Stay in a safe area (Muster Point) and act as a guide for company personnel responding to the situation and await further instructions from your supervisor. </li></ul>
    41. 43. <ul><li>Evacuation </li></ul><ul><li>Evacuation routes </li></ul><ul><li>Evacuation routes will be provided from every working area to muster points. These routes shall be kept free from obstruction and properly marked </li></ul><ul><li>Wind </li></ul><ul><li>An accurate wind forecast must be available and posted at all times. The wind direction must be shown by TWO VISIBLE WIND INDICATORS such as wind socks, illuminated at night </li></ul><ul><li>Alarm System </li></ul><ul><li>A dedicated alarm will be set at 5 ppm. Explosion proof horns and flashing lights will be provided which will be distinct from normal Fire and Evacuation alarms </li></ul><ul><li>Muster Points </li></ul><ul><li>Will be set up for all locations </li></ul>
    42. 44. ESCAPE FILTER
    43. 45. Emergency Telephone Numbers
    44. 46. Main Characteristics of H2S-Summary: Potentially lethal Heavier than air Colorless Readily dispersed by wind or air currents Flammable - burns with a blue flame Odor of rotten eggs ( below concentration of 100 ppm ) Highly Corrosive to certain materials (eg steel)