What is Gas Testing?

In this article, we will discuss about the Gas Testing and main points to know:

• The term gas testing explains the procedure for testing of toxic, oxygen deficiency / enrichment and flammable gases /vapors in the work area. 
• Does gas test basically, upwind of the worksite and then around the minimum of 5-meter radius of the worksite. Entire potential sources of release must be tested along with the risk spot
• Conducting through Gas Testing (GT) at above head height and at floor level to ensure that gases of different relative densities have the best possible chance of being detected

Portable Gas Monitors: 

Oxygen Deficient (OD) less than 10% atmospheres may not illustrate the true concentrations of combustible gas. 

POINTS TO KNOW:

• ADCO is producing Methane
• Up to 1.4 safe but when reach to 5% not safe 95% safety margin 
• Butane use in cigarette lighters
• Propane use for cooking and heating pipes before welding commence.
• Kerosene use for jet fuels
• Detector keep 5 meters before the job upwind.
• 3 seconds per foot tube getting time in detect, target result e.g. 50 ft =2.5 minutes
• No advantage uses the tube
• Measure 5 meters’ radius of worksite check. MLH
• Every 6 months’ calibration of gas detectors
• Bump test= o2 and LEL
• Turn off in 3 seconds 
• Too small or too big gas quantity will not ignite, fuel, oxygen and an ignition source
• Any amount of gas between Lower Explosive Limit (LEL) & Upper Explosive Limit (UEL) is two limits is explosive 
• Below Lower Explosive Limit (LEL) gas lean will not burn (too little gas) more air available
• Above Upper Explosive Limit (UEL) gas rich will not burn (too much gas) less air available 

Flammable gas /vapor - (LFL %) LEL % - (UFL %) UEL %   

• Acetylene.                                            2.5    to   81
• Butane.                                                1.9    to 8.5
• Carbon monoxide.                               12.5   to 74.2
• Ethane.                                                 3 to 12.5
• Fuel oil.                                                0.6 – 1.0   to   5-5.6   
• Gas oil.                                                 4.7 to 33
• Hydrogen.                                             4 to 74.2
• H2S.                                                      4.3 to 46
• Kerosene.                                             0.6 to 5.6
• Methane.                                              5 to 15
• Propane.                                               2.2 to 9.6          

When Inhale:

• Nitrogen (n2) 79%
• Oxygen (o2) 20 %
• Other gases – 1 %

When Exhale:

• Carbon dioxide (co2) 4 %
• Nitrogen (n2) 79 %
• Oxygen (o2) 16 %
• Other gases 1 % 

Lighter than Air:

• Acetylene – 0.9%
• Ammonia – 0.59%
• Co –             0.966
• Helium – 0.138%
• H2 – 0.069%
• CH4 -0.553%
• N2 – 0.972%

Heavier than Air

• Argon – 1.38%
• Arsine – 2.69%
• Co2 – 1.518%
• So2 – 2.264%
• Propane – 1.521%
• Butane – 2.1%
• Ozone – 1.660%
• O2 – 1.104%
• H2S – 1.19 %

Knowledge Point:

• H2s Molecular weight: 34.08 gm
• CO. LEL.12.5 %- UEL 74%
• CO. 800 PPM in atmosphere death 1 – 4 minutes
• This protects hemoglobin from releasing oxygen in tissues, effectively minimizing the oxygen-carrying capacity of the blood, leading to hypoxia.
• SO2 It is a respiratory irritant and causes coughing, 
• SO2 Heavier than H2S and air
• SO2 TLV-TWA  2 PPM & 5 PPM
• SO2 Sulfurous acid can damage around the eyes, corneas, lungs and respiratory tract
• Toxic of Ammonia: It is extremely irritating of the eyes, nose, throat and lungs and all moisture of the body
• Ammonia (NH3) Leakage of gases NH3 water is showered
• Leakage of liquid NH3 foam is used for blanketing
• Methane-CH4, Hydrogen-H2, Natural gas-NG
• N2. TLV/TWA  81%
• Nicotine gas used in cigarette
• Flammable: below 100 F’ temperature (ignition 37,77 c’)
• Combustible: above 100 F’ temperature (ignition 37,77 c’)

What is Co?

• Carbon monoxide (Co), a colorless, odorless, highly poisonous and combustible gas formed by the combustion reactors. 
• Slight exposure to headache and dizziness, while nausea & vomiting can follow the inhalation of `higher concentrations, unconsciousness and death can result from exposure to long amounts without any warning symptoms
• TLV-TWA 35 PPM STEL 50 PPM
• LEL.12.5 %- UEL 74%
• 800 PPM in atmosphere death 1 – 4 minutes

What is the effect of carbon monoxide in human body?

Carbon monoxide (CO) mainly causes adverse effects in humans by combining with hemoglobin to form carboxy hemoglobin (HbCO) in the blood. This protects hemoglobin from releasing oxygen in tissues, effectively minimizing the oxygen-carrying capacity of the blood, leading to hypoxia.

Question. What are the engineering controls for carbon monoxide? 

Answer. Engineering Controls: Use local exhaust ventilation, if general ventilation is not adequate to control amount in the air. Exhaust directly to the external side, taking any mandatory precautions for environmental protection & prevention. Install & Use non-sparking ventilation systems, approved explosion-proof equipment and intrinsically safe & secure electrical systems in areas where this product is used and stored

What is So2 (sulfur dioxide)?

• SO2 is one of the products formed when H2S is burned in the atmosphere and also formed when pyrophoric iron Sulphide oxidizes. It is also often present in combination with H2S.
• Sulphur dioxide is a colorless, non-flammable gas with a strong suffocating odor. It is a respiratory irritant and causes coughing, an increase in sputum production and Broncho-constriction (spasm of airways) at low concentrations.
• Highly toxic if inhaled
• Colorless & strong suffocating odor (typical smell of burning match tip)
• Heavier than H2S and air
• Dissolve in water & forms mild sulfurous acid
• Highly corrosive, acidic when wet
• TLV-TWA  2 PPM & 5 PPM STEL The 15-minute Short term
• Flammable range 500’f (c)
• I.D.L.H. SO2 = 20 PPM
• Ammonia-NH3
• Methane-CH4
• Hydrogen-H2
• Natural gas-NG

Physical Effect:

Sulfurous acid can damage around the eyes, corneas, lungs and respiratory tract

Ammonia (NH3):

• Toxic of Ammonia: It is extremely irritating of the eyes, nose, throat and lungs and all moisture of the body
• Not a toxic gas however it is still dangerous in case of NH3 leakage then 2 causes arises

1. Leakage of gases NH3 water is showered
2. Leakage of liquid NH3 foam is used for blanketing

Knowledge Point?

• Fiber glass reinforced plastic (FRP) withstand 328100 V/per meter (100.000 volts per foot) of length for five meters
• Noxious gas is any gas in the air which is harmful to life when in-held
• Oxygen no explosion of a methane air mixture. Can occur at 12%
• Gravity of oxygen 1.105%
• Gravity of hydrogen (H2) 0.0695 %
• Explosive 4.0 % to 74.2% as 5% oxygen present
• Detected by chemical analysis
• Violent explosion 7 to 8%
• One cubic foot of hydrogen at 60’ f and 30 inches of mercury pressure 5310000 (0.0053) of one pound
• SCNR: Selective non-catalytic reduction

Download File

What is Gas Testing?