JAFURAH COGENERATION PROJECT
Date: 27th April 2025
AGT - Authorized Gas Tester Test Paper
Time: 30 Min Marks: 45
Q.1. Who is AGT?
Q.2: Write name of three toxic gas.
Q.3: Why gases need to be tested?
Q.4: Write three flammable gas.
Q.5: Write three asphyxiant gas.
Q.6: What are the units for measuring concentration of gases?
Q.7: What are the atmospheric hazards?
Q.8: What is Oxygen deficiency?
Q.9: Which gases must be tested before issuing confined space entry
permit?
Q.10: At what value the low and high alarms of H2S sensor activates in
portable gas detectors?
Q.11: Is H2s gas is heavier than air?
Q.12: Write the sequence of gas testing?
Q.13: Validity of calibration test?
Q.14: Is Methane gas is heavier than air?
Q. 15: What is Short Term Exposure Limit (STEL)?
JAFURAH COGENERATION PROJECT
Date: 27th April 2025
1. AGT - Authorized Gas Tester is a person who appointed by
employer to carry out atmosphere test in critical environment
such as confined space, petrochemical, oil & gas plants to carry
out work safely.
AGT is a competent person who have required knowledge of gases
present in the critical environment and he can identify gases through
gas detector, there is a prime role of AGT before and during work in
critical environment. If you want to be an authorized gas tester you
need to cleat AGT exam test, in this blog post authorized gas tester
interview questions and answers are provided which will help you to
become am authorized gas tester.
2. Toxic Gas
• Carbon Monoxide
• Hydrogen Sulfide
• Chlorine
3.
Gases need to tested: -
a.
For Personal Safety
b.
For Area Monitoring
c.
For Confined Space Entry
d.
For Leak Check (Storage tank, equipment)
e.
For Emergency Response
f.
For Protection of environment
g.
For Process Safety
h.
For identifying flammable atmosphere to issue Hot work
permits
4. Flammable Gas: -
• Carbon Monoxide
• Hydrogen Sulfide
• Chlorine
5. Asphyxiant gas:-
• Nitrogen
• Organ
JAFURAH COGENERATION PROJECT
Date: 27th April 2025
• Helium
• An asphyxiant gas, also known as a simple asphyxiant, is a
nontoxic or minimally toxic gas which reduces or displaces the
normal oxygen concentration in breathing air. Breathing of
oxygen-depleted air can lead to death
by asphyxiation (suffocation). Because asphyxiant gases are
relatively inert and odorless, their presence in high concentration
may not be noticed, except in the case of carbon
dioxide (hypercapnia).
6.
• % (Percent) – Flammable gases
• ppm (parts per million) – Toxic gases
7. Atmospheric hazards
• Oxygen (deficiency and enrichment)
• Flammable gases and vapours
• Toxic contaminants
• Corrosive
8. Oxygen deficiency
The percentage of oxygen below 19.5 % in the environment is
considered as oxygen deficiency or lack of oxygen.
9. CO (Carbon Monoxide), O2 (Oxygen), H2S (Hydrogen
Sulphide), Combustible gas/hydrocarbon
10. Low 10 PPM & High 15 PPM
11. Yes, it is heavier than air.
Note: Yes, hydrogen sulfide (H₂S) is heavier than air. The
molecular weight of hydrogen sulfide is approximately 34.08
g/mol, while the average molecular weight of air is about 29
g/mol. Because of this difference, hydrogen sulfide tends to
accumulate in low-lying areas and can pose a hazard in confined
spaces.
JAFURAH COGENERATION PROJECT
Date: 27th April 2025
12. Gas Testing Sequence:
• Oxygen
• LEL (Flammable gas / Vapour)
• H2S
• CO
13. Validity of calibration test
6 months.
Note: Typical calibration frequencies for most applications are between
3 and 6 months, but can be required more often or less often based on
your usage.
14. No, it is lighter than air.
Note: The Deciding Factor
The density of a substance is its mass per unit volume. Air itself is a
mixture of gases, primarily nitrogen and oxygen, with an average
molar mass around 28.97 g/mol. Methane, with a molar mass of
approximately 16 g/mol, is less dense than air.
This lower density is the crucial point. Because methane is less dense
than the surrounding air, it tends to rise and disperse, rather than
settling to the ground. This is why methane leaks often rise into the
atmosphere, making detection and mitigation strategies more complex.
15. Short Term Exposure Limit
The maximum allowable concentration over 15 minutes
