WHAT IS H2S?
Hydrogen sulfide is a chemical compound with the formula H2S. It is a colorless gas with the characteristic foul odor of rotten eggs; it is heavier than air, very poisonous, corrosive, flammable, and explosive.
USUALLY FOUND IN
Oil and gas exploration/production/ processing
Water treatment plants
CHARACTERISTICS OF H2S?
At low concentrations, it smells like a “Rotten Egg”
At high concentrations, it “deadens the sense of smell”
Soluble in water and forms an acid, which causes pitting on steel.
Forms Pyrophoric metallic Sulfide Scales that are highly explosive in presence of Oxygen (O2)
Autoignition Temperature is 260°C
EFFECTS OF H2S ON MAN AT VARIOUS CONCENTRATIONS
100 ppm = 0.01 % – Deadens the sense of smell in 3 to 5 minutes . May burn eyes and throat and cause drowsiness.
500 ppm = 0.05% –
1000 ppm – 0.1% – Unconsciousness occurs immediately, followed by death or brain damage if not rescued promptly.
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HAZARDS OF H2S
Toxic- H2S is the second most toxic gas known to man.
Corrosive– H2S dissolves in water to form a weak acid that corrodes and pits metals.
Metallurgy- H2S may react with iron and steel causing hydrogen embrittlement and/or sulfide stress cracking. This lowers safety factors in tubular and pressure vessels.
Fire & Explosion – Hydrogen sulfide is a highly flammable gas and gas/air mixtures can be explosive. It may travel to sources of ignition and flashback. If ignited, the gas burns to produce toxic vapors and gases, such as sulfur dioxide.
Frostbite- Contact with liquid hydrogen sulfide causes frostbite.