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WELCOME TO

Gas Tester TrainingO2, LEL Monitoring

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OUR GOAL ?

• ZERO LOST TIME INCIDENTS

• ZERO MEDICAL INCIDENTS

• ZERO ENVIRONMENTAL INCIDENTS

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O2, LEL Monitoring•Purpose of monitoring:

To identify and control atmospheric hazards.

To assure the following atmospheric conditions

are met.

Oxygen must not be below 19.5% or above

23.5% by volume.

Flammable gas vapour, must be 0% of the lower

explosive limit.

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Definitions:Gas Tester :

Personnel who have received Competence Gas Testing Training and are authorized by Site HSE Manager in the use of Gas Testing Equipment.

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Definitions:Combustible % LEL: minimum concentration at which a gas will explode. A common unit of measurement is a percent of the LEL.Calibrated: a meter that has had its zero span & adjusted to within the manufacturer’s recommendation against a known calibration standard at least monthly.Oxygen Deficient Atmosphere: An atmosphere containing less than 19.5% oxygen by volume.

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Definitions:Oxygen Enriched Atmosphere: An atmosphere

containing more than 23.5% oxygen by volume.TLV: Threshold Limit Value refers to airborne

concentration of substances & represent condition under which it believed that nearly all workers may be repeatedly exposed day after day, 8 hours a day, 5 days a week over a prolong period of time without any adverse effect on their health.

PPM: Parts Per Million Parts: 1ppm = 1 gram.

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Definitions:TLV-TWA: Time Weighted Average: The average amount of gas (in ppm) a worker can be

exposed to over a certain time period. This time is defined as 8 hours to represent a normal working day.

TLV-STEL: Short Term Exposure limit:The average amount of gas (in ppm) a worker can be exposed to in a 15 minute period with no long term health effects. This may occur 4 times a shift with one hour between 15 minutes exposure.

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Definitions:PEL: Permissible Exposure Limit: Level of gas (in ppm) a worker can be exposed to 8

hours a day/40 hours a week for the rest of their life with no long term health effects.

IDLH: Immediately Dangerous to Life and Health:The maximum concentration of gas (in ppm) from which a worker could escape within 30 minutes without experiencing any escape-impairing or irreversible health effects.

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Definitions:• Class I Div. 1: A location in which ignitable

concentrations of flammable gases or vapors can exist under normal operating condition.

• Class I Div. 2: A location in which ignitable concentrations of flammable gases or vapors can exist only through accidental rupture, breakage or unusual faulty operation.

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Definitions:• Class II Div.1: A location in which combustible dust

in the air under normal operating conditions in quantities sufficient to produce explosive or ignitable mixtures.

• Class II Div. 2: A location in which combustible dust is not normally air in quantities sufficient to produce explosive or ignitable mixtures, & dust accumulation is normally insufficient to interfere with the normal operation of electrical equipment or other apparatus.

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COMBUSTIBLE GASES:The following are the lower explosive limits of selected gases which should be useful:

• Methane 5.0% of volume• Methyl Alcohol (Methanol) 6.0% of volume• Methyl Ethyl 1.4% of volume• N-Pentane 1.4% of volume• Propane 2.1% of volume• Propylene 2.0% of volume• Styrene 0.9% of volume• Acetylene 2.5% of volume• Benzene 1.2% of volume

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• Butane 1.9% of volume• Butyl Alcohol 1.4% of volume• Ethane 3.0% of volume• Ethyl Alcohol (Ethanol) 3.3% of volume• Ethylene 2.7% of volume• Ethylene Oxide 2.7% of volume• Hydrogen 4.0% of volume • Isopropyl Alcohol (Isopropanol) 2.0% of volume

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The following gases are heavier than air:• Argon toxic• Carbon Dioxide toxic• Ethane explosive• Hydrogen Chloride toxic/flammable• Nitrogen Dioxide toxic• Oxygen• Sulfur Dioxide toxic gas• Butane explosive• Chlorine toxic gas• Hexane explosive• Hydrogen Sulfide toxic gas/flammable• Methyl Mercaptan explosive• Nitrous Oxide toxic• Phosphine toxic/flammable• Propane explosive

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The following gases are lighter than air:• Acetylene

• Carbon Monoxide

• Hydrogen

• Methane

• Ammonia

• Ethylene

• Hydrogen Cyanide

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Sample Draw Time:Sample draw time depends upon the length of sampling hose.• For 2 feet (0.6 meter) long hose sample draw time is 1 second.• For 1 meter long sampling hose sample draw time is 1.5 second

• To monitor the atmosphere for: Oxygen O2 in % by volume Flammable – LEL- in % by volume Carbon mono oxide- CO – in PPM Hydrogen Sulfide - H2S- in PPM

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Operating Instructions:• Check the validity of calibration.• Check the inlet gas filter for cleanliness• Check cracks holes & loose joints.• Before each days use, the meters accuracy will be

compared against a known calibration standard.• Meters that fails this test will not be used.• Switch on the meter.• Check the sample line & fitting for the leak by plugging

the open end of the probe.

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Operating Instructions:• Meter will stop the suction pump & give

alarm. When the open end is unplugged it will start the pump & meter will start working.

• Blow the air in the sampling line gently. The oxygen percent will start falling down and gives low alarm at 19.5%.

• Now allow it to ventilates so that meter indicate 20.8% O2 normally. If reading differs from this cause should be determined.

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Operating Instructions:• Take meter to check near known combustible

gases for checking.• While sampling stand upwind to the source to

avoid inhalation & keep the sample probe to down wind side.

• Now LEL will start indicating the value & gives alarm at 10% LEL.

• Take meter away & check LEL will come down to 0% gradually.

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Operating Instructions:• Now meter is ready for use.• Meter must be used to detect those specified gases only.• Meter is not intended to detect other toxic gases.• Sampling line must not touch the liquid surface to avoid

damage to instrument.• Do not continue to use with its batteries in a depleted

condition.• Do not change setting of alarm.