Confined Space Training Certificate Atmospheric Hazards & Entry Procedures 3

Question 1

What does 'entry procedure' cover in confined space management beyond the permit to work?

Accepted Answer

Briefing of all personnel on hazards and roles, signing of the permit, pre-entry equipment checks, communication establishment, and standby procedures

Answer

The entry procedure includes: team briefing, permit review and signing, pre-entry atmospheric testing, equipment checks (rescue equipment positioned, gas detectors functional, communication tested), isolation verification, ventilation confirmed operating, and emergency services number available. All steps must be completed before the first person enters.

Question 2

Why should clothing and footwear for confined space entry be selected to avoid static electricity generation?

Accepted Answer

Static sparks can ignite flammable or explosive atmospheres in the confined space

Answer

Synthetic clothing and rubber-soled footwear can generate static electrical charges that discharge as sparks. In atmospheres with flammable or explosive gases between the LEL and UEL, a static spark is sufficient to cause ignition. Anti-static clothing and footwear reduce this ignition risk. In oxygen-enriched atmospheres, even natural fibres burn vigorously.

Question 3

What is the maximum safe level of carbon monoxide for confined space occupation without breathing apparatus?

Accepted Answer

20 ppm (8-hour TWA WEL) — above this, supplied-air BA or evacuation is required

Answer

The UK WEL for CO is 20 ppm (8-hour TWA) and 100 ppm (15-minute STEL). Work without supplied-air BA should not continue above the WEL. The IDLH for CO is 1,200 ppm, above which BA is absolutely essential. CO alarm setpoints in confined space detectors are typically set at 35–50 ppm as a warning threshold.

Question 4

What effect does high humidity in a confined space have on atmospheric monitoring?

Accepted Answer

High humidity can interfere with electrochemical sensors, affect catalytic bead sensors, and cause condensation on sample lines, potentially affecting reading accuracy

Answer

High humidity can interfere with electrochemical sensors (causing drift or incorrect readings for H2S, O2, CO), condense in sample tubes (blocking or diluting the gas sample), and affect pellistor sensors. Detectors should be humidity-rated for the expected conditions, and sample lines checked for condensation before use.

Question 5

What is the correct procedure when a confined space entrant first notices they feel dizzy or unwell?

Accepted Answer

Immediately signal the attendant and exit the space without delay — do not wait to see if symptoms worsen

Answer

Dizziness or feeling unwell in a confined space may be the first sign of toxic gas exposure or oxygen deficiency — conditions that can progress to unconsciousness within seconds. The entrant must signal the attendant and exit immediately. Waiting to see if symptoms worsen may result in incapacitation before exit is possible.

Confined Space Practice Test

Confined Space Practice Test

Confined Space Training Certificate Atmospheric Hazards & Entry Procedures 3