HSE DOCUMENTS-HYDROGEN SULPHIDE (H2S) AWARENESS TRAINING

HYDROGEN SULPHIDE (H2S) AWARENESS TRAINING

TABLE OF CONTENTS 

1.0. Course Objective

2.0. Class Topics

3.0. Production & Occurrence

4.0. H2S Occurrence

5.0. Names

6.0. Properties and Characteristics of H2S

7.0. H2S is an Irritant

8.0. H2S affects our body

9.0. Exposure Limits

10.0. TEL, Ceiling, and TWA

11.0. Different concentrations of H2S

12.0. Flammability

13.0. SO2

14.0. SO2 – Sulfur Dioxide

15.0. Corrosiveness

16.0. Detection & Monitoring

17.0. Personal Monitor & Gas Detector

18.0. Fixed Monitor

19.0. Alarm System

20.0. Stay wind smart

21.0. PROTECTION AGAINST H2S

22.0. SCBA

23.0. Using SCBA

24.0. Rescue Procedures

25.0. First Aid Procedures

1.0. Course Objective

1.1. To prepare the Employees to know what are the potential hazards when working around the environment of Hydrogen Sulphide.

1.2. How to protect themselves from H2S, and other employees. 

2.0. Class Topics

2.1. Production

2.2. Properties and Characteristics

2.3. Effect on our Body

2.4. Exposure Limits

2.5. Monitoring

2.6. Emergency Procedures

2.7. Rescue

2.8. First Aid Procedures 

3.0. Production & Occurrence

3.1. H2S is a deadly gas comprising one atom of sulfur and two atoms of hydrogen.

3.2. H2S formed when bacteria break the sulfur-rich proteins found in dead plants and animals where oxygen is not present

3.3. H2S is created by chemicals or bacteria introduced into the formation during production operations. Such as acidizing or water 

4.0. H2S Occurrence

4.1. The largest industrial producer of H2S is the Petroleum Industry.

4.2. Other sources include coke ovens, paper mills, and tanneries.

4.3. H2S gas can also be present naturally in well water, is used widely in refining processes, and sometimes in sewerage lines and manholes. 

5.0. Names

5.1. There are many names for H2S

5.2. Sour Gas

5.3. Rotten Egg gas

5.4. Sulphureted Hydrogen

6.0. Properties and Characteristics of H2S

6.1. There are many other names for Hydrogen Sulphide but the most common name is‘H2S’ 

6.2. Colorless

6.3. Offensive odor (rotten eggs)

6.4. Concentrations >100ppm (Parts per Million) paralyze the sense of smell

6.5. Extremely toxic

6.6. Easily dispersed by wind or fans

6.7. Flammable

6.8. Flammable Range from 4.3% LEL – 46% UEL

6.9. Corrosive

6.10. Heavier than air (specific gravity 1.189)

6.11. Soluble in oil and water. 

7.0. H2S is an Irritant

7.1. H2S is an irritant gas when reacts to water it forms a weak acid.

7.2. There is water in our eyes, nose, throat, and respiratory system which leads to irritation

7.3. Examples: burning eyes, sore/scratchy throat, and coughing, respiratory irritation. 

7.4. Normal Breathing System

7.5. When we breathe we breathe in oxygen and gas exchange takes place through air sacks (alveoli) in our lungs.

7.6. We then breathe out oxygen and carbon dioxide

7.7. Oxygen Reaction with blood

7.8. This oxygen is mixed with our red blood cells and when this blood moves in our body and brain our whole body gets oxygen as a result we can breathe.

7.9. H2S reacts to our brain:

• Once H2S is in your brain it attacks the respiratory control center. H2S tries to shut it down, and as a result, we cannot breathe.
• H2S also deadens the sense of smell.
• At a concentration of greater than 100 ppm, your sense of smell is finished.
• So never trust your nose to detect H2S.

8.0. H2S affects our body

H2S affects our body depends on three ways:

8.1. Duration:

• How long have you been exposed to H2S

8.2. Intensity:

• What is the concentration of H2S?

8.3. Susceptibility:

• The Health of Individuals 

9.0. Exposure Limits

9.1. PEL (Permissible Exposure Limit):

• Defined as a maximum air concentration you can be exposed for 8 hours a shift or 40 hours a week without respiratory protection.
• Established by OSHA, making it law.
• PEL for H2S = 10 PPM (Parts per Million)
• In PEL you cannot exceed 10 PPM (Parts per Million) at any time.

9.2. STEL (Short-Term Exposure Limits):

• Some gases and vapors have an allowable maximum Short Term Exposure Limit
• Based on 15-minute time exposure STEL for H2S= 15 PPM (Parts per Million)

9.3. IDLH (Immediately dangerous to life and Health):

• At once affects your body, irritation in your eyes, nose, and throat and you lose your sense at this concentration.
• IDLH for H2S = 100PPM (Parts per Million)

9.4. TWA (Time Weighted Average):

• Defined as the maximum concentration of any toxic gas to which a worker can be exposed for an average of 8 hours a shift or 40 hours a week.
• TWA for H2S = 10 PPM (Parts per Million)
• You can cross this range or less than this range, but your average should be
• 10 PPM (Parts per Million) for 8 hours. Also, do not cross the ceiling value at any time or 15 PPM (Parts per Million) for 15 min only.

9.5. Ceiling:

• Ceiling is the maximum concentration to which an unprotected worker may be exposed.
• Ceiling concentration should never be exceeded even for an instant
• The ceiling for H2S = 25 PPM (Parts per Million)

10.0. TEL, Ceiling, and TWA

11.0. Different concentrations of H2S

11.1. With different concentrations of H2S different effects on our health

11.2. 1 PPM              Smell (rotten egg)

11.3. 10 PPM            8 hr. TWA

11.4. 15 PPM            15 min

11.5. 100 PPM          Lose sense of smell, coughing, burning in eyes, headache and dizziness, and respiratory Irritation.

11.6. 300 PPM         Loss of consciousness with a time less than 30 min.

11.7. 1000PPM        Immediate respiratory arrest, loss of consciousness, followed by death. 

12.0. Flammability

12.1. H2S is a highly flammable and explosive gas

12.2. The flammability range

12.3. LEL = 4.3% or 43,000PPM: 1% = 10,000 PPM

12.4. UEL = 46% or 460,000 PPM

12.5. When H2S gets fire there is another toxic gas SO2 (Sulfur dioxide)

12.6. PEL for S02 = 2 PPM

12.7. IDLH for SO2 = 20 PPM 

13.0. SO2

13.1. SO2 is a colorless and highly toxic gas.

13.2. When it reacts with water it forms a weak sulfuric acid.

13.3. It burns with a blue flame.

13.4. It can suffocate the victims.

13.5. It will also burn your lungs from the inside by forming acid and destroying the alveoli.

13.6. Specific gravity of SO2 is 2.264 (where air = 1).

13.7. So it is heavier than air.

14.0. SO2 – Sulfur Dioxide

2 PPM: Safe 8-hour Exposure- TLV

5 PPM: Pungent detectable odor- STEL

12 PPM:     Severe chest constriction, throat &eye irritation – TLV- C

100 PPM:  Immediately Dangerous to Life & Health- IDLH

500 PPM:  Causes nausea, and suffocation even at first breath

15.0. Corrosiveness

15.1. H2S corrodes the carbon steel readily.

15.2. The oxidization (rusting) on the surface of the metal from iron sulfide scale, or black scale.

15.3. The iron sulfide scale is pyrophoric.

15.4. Iron sulfide will flash as it dries and is exposed to air.

15.5. H2S also produces corrosiveness in pipelines and drilling equipment causing them to break down. 

16.0. Detection & Monitoring

16.1. An essential part of an effective safety procedure

• Human senses cannot be relied upon
• At very low concentrations, H2S paralyzes the sense of smell.
• Always trust on gas monitor.
• When they give the alarm evacuate immediately. 

16.2. There are two types of monitoring

Many years ago some kind of animal detected H2S

• Personal Monitor
• Fixed monitors

17.0. Personal Monitor & Gas Detector

17.1. Small and convenient

17.2. Can be taken everywhere with you and is easy to use.

17.3. Monthly Pump check

17.4. Three months calibration.

17.5. Give alarm at 10 PPM

17.6. There is vibration, light, and alarm 

18.0. Fixed Monitor

18.1. On the rig floor at the Driller’s position and about 18 inches above the floor.

18.2. At the top of the bell nipple.

18.3. At the flow line opening to the shale shaker.

18.4. Cellar or underneath the choke manifold, above the choke manifold skid floor

19.0. Alarm System

19.1. Amber strobe lights and horn

19.2. First alarm at 10 ppm (visual)

19.3. High alarm at 20 ppm (visual & audible).

19.4. The alarm system shall be located in a clearly visible 

locations so that personnel in any work area can 

see and/or hear at least one set.

19.5. Audible alarms be inside the rig site living quarters.

19.6. The H2S alarm system shall be positioned at the rig camp 

so that all personnel can see and hear the alarm. 

20.0. Stay wind smart

20.1. Always pay attention to flags or wind socks

20.2. When the alarm sounds retreat crosswind to a safe breathing area.

21.0. PROTECTION AGAINST H2S

These are the types of respirators for the H2S environment

21.1. Air Line Unit

21.2. Escape unit

21.3. Self-contained breathing apparatus (SCBA)

• H2S Environments require Positive Pressure in the face mask
• Pushes the air out of the leaks instead of letting you pull toxic gases in 
• The cylinder contained grade D or grade E air, not pure oxygen.
• Air contains many gases

21.4. Escape Unit:

• This contains only 5 min of air
• Not used for rescue or work

21.5. Air Line unit:

• This contains only 15 min air and this 15 min air is used for escape.
• Use for work after taking the line from the cascade system. 

22.0. SCBA

SCBA (Self-Contained Breathing Apparatus). This contained only 30 of air. When we use SCBA

22.1. Gas testing

22.2. Rescue of casualty in enclosed or confined space

22.3. Firefighting

22.4. Containing or cleaning toxic spills

22.5. Where the use of cascade system air supply dangerous

22.6. Recovering control of adverse operational situation

22.7. In case of an emergency 

22.8. SCBA key features:

• Positive pressure system
• Open circuit
• Demand valve
• Pressure reducer 

22.9. SCBA face mask difficulties:

• Facial hair
• Spectacles
• Using a mask in an enclosed space
• Small or irregularly shaped faces 

23.0. Using SCBA

23.1. Prepare Equipment – check cylinder pressure, face piece, and harness.

23.2. Put on Cylinder – adjust and tighten straps.

23.3. Put on Face piece – Tighten straps starting at the chin first.

23.4. Negative Pressure Test – Block the face piece opening and breathe in to check for seal and breathe out to check the exhalation valve.

23.5.Connect Air – Open the cylinder, connect the regulator, and breathe. 

24.0. Rescue Procedures

• 24.1. H2S kills many of us when we are not trained, and we attempt rescue.
• 24.2. Remember always to protect yourself first than others.
• 24.3. Always work in pairs or use the buddy system
• 24.4. You should know how to use SCBA.
• 24.5. If you are not trained do not do rescue 

A. Step 1 – Evacuate immediately – if there is a release of H2S you must evacuate the areas immediately, moving upwind or crosswind and to a higher location.

B. Step 2 – Sound the Alarm – notify the control room that there is an H2S release and where. Ask for help.

C. Step 3 – Assess the Situation – quickly assess if other hazards could put you at risk. (Explosive mixture)

D. Step 4 – Protect yourself by putting on SCBA. Always don breathing air before attempting a rescue. Use SCBA packs and never escape packs for performing a rescue. 

E. Step 5 – Rescue the victim – You may rescue yourself if you know help is coming. Move the victim upwind to fresh air.

F. Step 6 – Revive the Victim – assess the victim for vital signs. If not breathing artificial respiration must be started.

G. Step 7 – Get Medical Aid – All H2S victims require medical attention. Never leave the victim alone. 

25.0. First Aid Procedures

25.1. Determine unresponsiveness

25.2. Open the airway.

25.3. Give 2 slow breaths

25.4. Check for a pulse

25.5. If no pulse, begin chest compressions. 

25.6. 30 compressions and 2 slow breaths.

25.7. After 4 cycles or 1 minute, check pulse again.

Note: you should be trained in CPR before administering it.

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