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Hydrogen Sulphide (H2S)




HYDROGEN SULPHIDE (H2S) 

Characteristics 

1. Flammable  

2. Soluble in water and oil and make H2SO4 with water 

3. Colorless  

4. Poisonous  

5. Explosive 

6. Corrosive  

7. Pyrophoric 

8. Heavier than Air (1.189 times)  

9. Invisible 

10. Toxic 

Safety Precautions 

  • Carry a H2S personal monitor & escape mask at every opportunity. Know at least 2 Escape routes from your work place.

  • Always check wind direction. 
  • Be aware of updated emergency action dril.
  • Notify and prominently display information relating to safety measures and emergency procedures in the site.Never go to a low-lying area during H2S  leak. 

  • Display H2S warning sign in H2S prone areas. H2S Safety induction training should be given to all employees H2S Safety induction training should be given to all employees.

TLV (THRESHOLD LIMIT VALUE)/ TIME WEIGHTED AVERAGE (TWA): 

The concentration to which it is believed that a person can be exposed continuously for 8 hours/ day (or 40 hours/week) of time without suffering from irritation, chronic of irreversible tissue damage and reduce work efficiency.

STEL (SHORT TIME EXPOSURE LIMIT): 

The maximum concentration chemical to which workers may be exposed continuously for up to 15 minutes without

danger to health or work efficiency and safety. 

  • Short Term Exposure Limit (STEL) when exposed only for a short period of 15 minutes. This maximum concentration can

be allowed to breathe 4 times during 8 hours with minimum 1-hour interval between exposures. 

Health effects of H2S: 
  • Low concentration - irritation of eyes, nose, throat, or respiratory system. 
  • Moderate concentration - more severe eye and respiratory effects, headache, dizziness, nausea, coughing, vomiting and difficulty breathing.
  • High concentration - shock, convulsions, unable to breathe, coma, death; effects can be extremely rapid (within a few breaths).

LEL (Lower Explosive Limit)  
It is the lowest concentration of fuel in air that will just support a self-propagating flame. 
UEL (Upper Explosive Limit) 
It is the highest concentration of fuel in air that will just support a self-propagating flame  
  • Note: Concentrations lower than the Lower Explosive Limit are 'too lean' to burn; those above the Upper Explosive Limit (UEL) are too rich to burn. Fuels will burn, only if their concentration in air is within the range of their LEL and UEL

Immediate Danger To Life And Health (IDLH):(100 PPM)  An atmosphere that poses an immediate threat to life, would cause irreversible adverse health effects, or would impair an individual’s ability to escape from a dangerous atmosphere. 

  • Threshold Limit Value (TLV) is 10 PPM for 8 hours. 
  • Short Term Exposure Limit (STEL) is 15PPM.  
  • Lower Exposure Limit (LEL) is 4.3 %( 43000PPM). 
  • Upper Exposure Limit (UEL) is 46 %( 460000PPM).  
  • Auto ignition temperature is 500 F (260 c). 
  • 1% H2S is10000 PPM 

Devices to Identify H2s At Site: 

1. Fixed Detector 

2. Personal monitor 

3. Multi gas detector 

4. Wireless detectors 

Emergency Response While Your Personnel Monitor Giving Alarm: 

  • Stop the activity what you are doing;  
  • Shut off the equipment ;( to avoid any other emergency because of running equipment). 
  • Hold the breath; 
  • Don the EEBA(Emergency Escape Breathing Apparatus); 
  • Watch wind direction;  

  • Proceed to safe location by cross wind direction; 
  • Then upwind direction and go to nearest assembly point ,  
  • Check the roll call/ head count and Inform as per incident protocol. 
  • Monitoring for sign or symptoms of exposure; 
  • Providing or requesting assistance if needed; and  
  • Being prepared to direct employees as to instructions given by senior management 

Self-contained Breathing Apparatus (SCBA), its types and components? 

A self-contained breathing apparatus (SCBA) is a type of respiratory protection equipment or device worn by rescuers, fire-fighters and others to provide breathable air in an Immediate Dangerous to Life of Health (IDLH) atmosphere. SCBA supply fresh air or oxygen to the wearier for 30-60 minutes.

SCBA are found in two types: 

1. Closed-circuit type (or Rebreather) – This type of SCBA filters, supplements and recirculates exhaled gas. CO2 from exhaled gas absorbed and fresh O2 recirculated. Closed-circuit SCBA contains pure oxygen in their cylinder.

2. Open-circuit type – This type of SCBA are filled with filtered, compressed air rather than pure oxygen. 

Components of SCBA: 

SCBA typically has three main components 

1. High pressure tank (e.g., 153 to 310 bars) - air cylinders are made of aluminum, steel or of a composite construction (usually carbon-fiber). Carbon fiber cylinders are the lightest in weight, therefore preferred, 

2. A pressure regulator, 

3. Inhalation connection (e.g., mouth-piece, mouth mask or face mask). 

Breathing Apparatus: 

EEBA (Emergency escape breathing  Apparatus)

For evacuation purpose.-15 Minutes of duration. 

SCBA (Self Contained breathing apparatus) :

For Rescue operation and confined space work purpose.-30/45 Minutes of duration. 

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