CMC CMC Toxic Gas Detection & Monitoring

Question 1

What is the IDLH (Immediately Dangerous to Life or Health) concentration for hydrogen sulfide (H2S)?

Accepted Answer

100 ppm

Answer

50 ppm

Answer

200 ppm

Answer

500 ppm

Question 2

Which instrument is most commonly used to detect oxygen-deficient atmospheres in marine confined spaces?

Accepted Answer

Electrochemical oxygen sensor

Answer

Colorimetric tube detector

Answer

Catalytic bead combustible gas indicator

Answer

Photoionization detector

Question 3

What minimum oxygen concentration must a marine confined space atmosphere maintain for safe entry without SCBA?

Accepted Answer

19.5%

Answer

16.0%

Answer

18.0%

Answer

21.0%

Question 4

A photoionization detector (PID) is best suited for detecting which class of compounds in marine spaces?

Accepted Answer

Volatile organic compounds (VOCs)

Answer

Carbon monoxide

Answer

Methane

Answer

Hydrogen sulfide

Question 5

What does a Lower Explosive Limit (LEL) reading of 10% on a combustible gas indicator actually represent?

Accepted Answer

The gas concentration is 10% of the LEL value

Answer

10% of the atmosphere is flammable gas

Answer

The space is 10% as dangerous as the UEL

Answer

10% of all molecules are combustible

Question 6

Which condition requires immediate evacuation of a marine confined space during monitoring?

Accepted Answer

Combustible gas at 5% LEL

Answer

Oxygen at 20.5%

Answer

Carbon monoxide at 35 ppm

Answer

H2S at 1 ppm