Confined Space Training Certificate Gas Testing & Monitoring

Question 1

In what order should a multi-gas detector test for atmospheric hazards in a confined space?

Accepted Answer

Oxygen, flammable gas (LEL), carbon monoxide, hydrogen sulphide

Answer

Carbon monoxide first as it is most toxic, then oxygen

Answer

Hydrogen sulphide first as it is the most lethal gas

Answer

Order does not matter as all readings are simultaneous

Question 2

What is the standard alarm setpoint for oxygen deficiency on a confined space multi-gas detector?

Accepted Answer

19.5% O2

Answer

18% O2

Answer

20% O2

Answer

17% O2

Question 3

How should gas testing be carried out before a confined space entry into a deep chamber?

Accepted Answer

By lowering the detector on a rope to test at multiple levels — top, middle, and bottom

Answer

By holding the detector at arm's length above the entry point

Answer

A single test at the entry point is sufficient for any depth

Answer

By inserting a sample tube and testing only at the breathing zone level

Question 4

What is the correct action if a gas detector alarms during a confined space entry?

Accepted Answer

All entrants must immediately evacuate via the shortest safe route without delay

Answer

Continue working while investigating the cause of the alarm

Answer

Contact the permit issuer by phone before taking any action

Answer

Only evacuate if a second alarm sounds within two minutes

Question 5

What is the difference between a catalytic bead (pellistor) sensor and an electrochemical sensor in a gas detector?

Accepted Answer

Pellistors detect flammable gas concentration (%LEL); electrochemical sensors detect toxic gases and oxygen

Answer

Pellistors are more accurate than electrochemical sensors in all conditions

Answer

Electrochemical sensors only work in warm temperatures

Answer

Pellistors detect oxygen; electrochemical sensors detect flammable gases

Question 6

Why must gas detectors be zeroed in fresh air before use in a confined space?

Accepted Answer

To establish a clean baseline so that any deviation from normal atmospheric composition is detected accurately

Answer

To warm up the sensors — zeroing has no calibration function

Answer

To comply with permit to work paperwork requirements

Answer

To check battery level before entering the space