Soluble in both water, 4 volume gas in 1 volume water at 0 degree Celsius (Produce irritable gas) and liquid hydrocarbons
This gas can be released when the liquid is agitated, such as when wading through water in excavations.
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.
Extremely toxic (almost as toxic as Hydrogen Cyanide) and 5 to 6 times as toxic as Carbon Monoxide.
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.
DO NOT DEPEND ON SMELL TO DETECT H2S
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.
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%
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
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
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
If we see any person we think may have been affected by H2S, we must help him,
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
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)
FACING SUCH AN INSIDIOUS AND DANGEROUS ENEMY, THE SAFEST METHOD IS TO APPLY ALL SAFETY RULES WITHOUT ANY HESITATION