hydrogen sulfide safety etech environmental & safety solutions, inc
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ObjectivesObjectives At the completion of this class, students will be
able to:Recognize the potential for exposure and the characteristics of H2S
Understand and describe the effects of H2S on humans and metals
Identify the presence of H2S and understand the use of appropriate protective measures
Objectives…ContinuedObjectives…Continued
Understand basic notification procedures
Understand the basic use of detection equipment
Understand basic rescue and safety measures
Demonstrate the correct use of protective equipment
Meet the certification requirements for H2S training
Physical PropertiesPhysical Properties
Odor:Similar to rotten eggsCan be detected by smell at less than ¼ of 1 part per millionNo smell at high concentrations
NeverNever trust your sense of smell as the detection method for H2S
SourceSource
H2S is caused by the decomposition of organic material (animal and/or vegetable)
Is found in:Natural GasProduced OilSewers & swampsOther industrial processes
Chemical FormulaChemical Formula
Is comprised of 2 parts hydrogen and 1 part sulfur
Simple compound
Hydrogen and sulfur will readily combine
Hydrogen Atoms
Sulfur Atom
Vapor DensityVapor Density
Colorless, heavier than air (VP = 17.6 atm)Will settle into low spotsEasily dispersed by wind or air currents
AvoidAvoid low-lying areas where H2S is present
Boiling PointBoiling Point
Will boil at –76o f
Has to be below -76o f to become a solid
Will likely be encountered as a gas
Explosive LimitsExplosive Limits
Has an explosive range of 4.0 - 44%
Explosive range for gasoline is 1.5 – 7.6%
Can dramatically increase the volatility of natural gas
Park your vehicle well awaywell away from any exhaust sources of H2S
PPM vs PercentPPM vs Percent To convert parts per million (ppm) to percent, move the
decimal 4 places to the left:
• 1 ppm = .0001% or 1/10,000 of 1%
• 10 ppm = .001% or 1/1,000 of 1%
• 100 ppm = .01% or 1/100 of 1%
• 500 ppm = .05% or 5/100 of 1%
• 1000 ppm = .10% or 1/10 of 1%
• 10,000 ppm = 1%
SolubilitySolubility
Is readily soluble in water
Can be found in water handling systems of separation processes
Will stay in solution if not treatedIs mechanically treated via heat or agitation
Auto-IgnitionAuto-Ignition
Will spontaneously ignite and burn at 500o fNatural gas has a higher auto-ignition temperature
Do not smoke or use an open flame in the presence of H2S
MetalsMetals
Highly corrosive to certain metals
Causes hydrogen embrittlement (sulfide stress cracking)
Failure is often abrupt
When BurnedWhen Burned
Produces a blue flameGives off sulphur dioxide (SO2)– Is very toxic
Methane based natural gas produces a yellow to orange flame
Neither methane gas or H2S will create smoke
Physiological HazardsPhysiological Hazards
ToxicityIs more toxic than Carbon MonoxideNearly as toxic has Hydrogen Cyanide
Physiological Hazards…ContinuedPhysiological Hazards…Continued
Typical Body Responses
0.13 ppm Minimal perceptible odor
4.60 ppm Easily detectable, moderate odor
10 ppm Beginning of eye irritation
27 ppm Strong, unpleasant odor
100 ppm Coughing, eye irritation, loss or sense of smell
Source: ANSI
Physiological Hazards…ContinuedPhysiological Hazards…Continued
Typical Body Responses(Continued)
200 - 300 ppm Marked conjunctivitis and respiratory tract irritation
500 - 700 ppm Loss of consciousness & possible death
700 - 1000 ppm Rapid unconsciousness, cessation of respiration, death
1000 – 2000 ppm Unconscious at once, death may occur even if the victim is removed to fresh air at once
Source: ANSI
Sulphur Dioxide (SO2)Sulphur Dioxide (SO2)
By product when H2S is burned
Heavier than air Colorless Lethal at high concentrations In the presence of moisture forms a mild sulphuric acid Readily dispersed by wind & air currents
SO2 ToxicitySO2 Toxicity
3-30 ppm Slight respiratory irritation
30-50 ppm Altered sense of smell & taste, increased fatigue
50-100 ppm Maximum permissible exposure for ½ hour
200-400 ppm Intolerable by humans, could lead to serious illness or death
400-500 ppm Immediately dangerous to life and healthSource: NIOSH
How H2S Affects IndividualsHow H2S Affects Individuals
Routes of Exposure:LungsEyes (Irritant)
Target Organs:BrainEyesLungs
How H2S Affects IndividualsHow H2S Affects Individuals
Other Factors:Duration (Length of exposure time)Intensity (Level of concentration)Individual Susceptibility (Each individual reacts differently to H2S exposure)
Symptoms of ExposureSymptoms of Exposure Skin Irritation Eye Irritation Fatigue Nausea Headache Loss of appetite
Dizziness Irrational behavior Dryness in nose, throat Coughing Loss of consciousness Cessation of all life processes
Symptoms may occur individually or in combination
Effects On MetalEffects On Metal Higher hardness steel is more prone to
embrittlement
Causes stress fractures
Causes Crystallization
Is prone to acid gas corrosion
May form iron sulfide
DetectionDetection
Colormetric TubesReact with H2S to change color in the tube media
Direct Reading InstrumentsPersonalAreaRemote
NeverNever trust your sense of smell for the detection of H2S!!!
ReportingReporting
Report any known presence or suspicions of H2S presence to your supervisor immediately
RescueRescue
Never effect a rescue before first donning proper respiratory protection and calling for assistance
Move the victim to a side wind area safely away from the source
Administer first aid as neededBeware that higher concentrations may be in the victim lungs
Basic H2S Safety RulesBasic H2S Safety Rules
Evacuate if levels of 10 ppm or greater are detected
Use respiratory protection in areas greater than 10 ppm
This level may be greater if dictated by local authority or your
Company’s policy
If you work in an H2S area, make sure respiratory protection is available, check it dailydaily
Do not depend upon your sense of smell to detect H2S
Basic H2S Safety Rules…
Continued
Basic H2S Safety Rules…
Continued
Always use the “Buddy” system when working in H2S environments
Do not attempt rescue unless you have been properly trained, have first called for assistance and have donned proper respiratory protection
Move cross-windcross-wind when exiting an H2S release
Get victim to medical attention immediately
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