Confined Space Training Certificate Atmospheric Hazards and Gas Testing 2

Question 1

A multi-gas detector used for confined space entry should, as a minimum, monitor for which four gases?

Accepted Answer

Oxygen, combustible gases (LEL), carbon monoxide, and hydrogen sulphide

Answer

Nitrogen, argon, helium, and neon

Answer

Carbon dioxide, ozone, radon, and methane

Answer

Propane, butane, acetylene, and ethylene

Question 2

What is the Workplace Exposure Limit (WEL) for carbon monoxide as an 8-hour time-weighted average in the UK?

Accepted Answer

20 ppm

Answer

50 ppm

Answer

100 ppm

Answer

10 ppm

Question 3

An oxygen-enriched atmosphere in a confined space (above 23.5%) is dangerous primarily because:

Accepted Answer

It greatly increases the risk of fire and causes materials to ignite more easily

Answer

It causes workers to become drowsy

Answer

It reduces the effectiveness of gas detectors

Answer

It causes nitrogen narcosis

Question 4

Continuous atmospheric monitoring during confined space work is important because:

Accepted Answer

Conditions can change rapidly due to work activities, chemical reactions, or ingress of contaminants

Answer

Gas detectors need constant power to remain accurate

Answer

It is only required by the Regulations for spaces deeper than 3 metres

Answer

Pre-entry testing is always sufficient on its own

Question 5

Before relying on a gas detector for confined space entry, the instrument must be:

Accepted Answer

Bump tested or calibrated in accordance with the manufacturer's instructions

Answer

Charged to at least 50% battery

Answer

Visually inspected only

Answer

Tested by holding it near a vehicle exhaust

Question 6

Which of the following is a common cause of oxygen depletion in confined spaces?

Accepted Answer

Rusting of steel surfaces, which consumes oxygen through oxidation

Answer

Using LED lighting inside the space

Answer

Opening the access hatch fully

Answer

Using battery-powered tools