Gas Percentages and PPM

Question 1

What percent of oxygen

Flammable liquid ceases
All flammable combustion ceases
All combustion ceases

Answer 1

17%
10%~12%
2%

Question 2

For nitrogen dioxide what is the:
TWA
STEL
IDHL

Answer 2

3ppm
5ppm
20ppm

Question 3

Carbon Dioxide. A person must not be exposed to an atmospheric concentration at a coal mine exceeding a general body concentration of carbon dioxide exceeding and convert % to ppm of above: TWA-%~ppm
STEL-%~ppm

Answer 3

TWA-1.25%~12500 ppm

STEL-3%~30000ppm

Question 4

Explain the effect of the following CO2 concentrations on a person:
2%
4.5%~5%
10%

Answer 4

a) 2%- 50% increase in lung ventilation
b) 4.5-5%- Anxiety, panic, irritability
c) 10%- Toxic, depresses CNS, violent panting, exhaustion, headache

Question 5

State the long-term exposure limit concentrations for:

a) Carbon Monoxide:
b) Hydrogen Sulphide:
c) Sulphur dioxide:
d) Nitrogen Dioxide:

Answer 5

a) Carbon Monoxide: 30 ppm
b) Hydrogen Sulphide: 10 ppm
c) Sulphur dioxide: 2 ppm
d) Nitrogen Dioxide: 3 ppm

Question 6

Is CO an explosive gas and and at what concentration

Answer 6

Yes 12.5%~74.2% explosive range

Question 7

What is the ignition temperature of Methane

Answer 7

537c

Question 8

What is the minimum concentration of oxygen at normal temperature for methane explosion to occur

Answer 8

12.2%

Question 9

What is the explosive range of methane in normal air and temperature

Answer 9

5%~15%

Question 10

What is the most easily ignited % of methane from a heated surface in a mixture of CH4 and air

Answer 10

5%~6%

Question 11

What is the lag ignition for methane at 5%~6%

Answer 11

2 seconds

Question 12

What effect can the presence of coal dust suspended in the atmosphere have on the LEL of methane

Answer 12

It can lower the LEL from 5% to 0%

Question 13

What % of methane is recognised as the most explosive in air

Answer 13

9.5%of mixture

Question 14

What concentration of H2s causes dizziness,excitement,nausea,dryness and pain in the nose/ throat/chest and irritation of the mucous membranes ?

Answer 14

250 ppm to 600 ppm

Question 15

Is H2s flammable and at what percentage in air

Answer 15

Flammable gas at 4.3%~45%

Question 16

State the maximum exposure limit of NO2

STEL

Answer 16

STEL 5ppm

Question 17

What should the oxygen sensor of a hand held gas detector read

Answer 17

20.9%

Question 18

What is the minimum oxygen level required for correct operation of a catalytic combustion sensor

Answer 18

10%

Question 19

What is the normal measuring range for a Wheatstone bridge or pallistor ( catalytic oxidation principle ) type of methanometer

Answer 19

0%~5% LEL

Question 20

What does T90 refer to when using a personal gas detector

Answer 20

The time taken to reach 90% of the test gas concentration of no more than 30 seconds

Question 21

Oxygen % explain the effects
16%~14%
14%~10%
10%~6%

Answer 21

16%~14% - Slight increase in pulse and breathing/ night and colour vision affected
14%~10% - Poor judgment/abnormal fatigue
10%~6% - Nausea/vomiting

Question 22

Minimum concentration of oxygen which coal mine workers can be exposed

Answer 22

19.5%

Question 23

Gases that constitute normal air and percentages

Answer 23

Oxygen 20.9%
Nitrogen 78.08%
Carbon Dioxide.04%
Argon/Inert gases .93%
Water vapour 0-3%