100+ Free HSE Surface Supplied Diver Practice Questions

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2026 Statistics

Key Facts: HSE Surface Supplied Diver Exam

100 MCQs

Practice Questions

HSE Commercial Diving Syllabus

180 Mins

Time Limit

HSE Assessment Guidelines

75%

Passing Score

HSE Commercial Diving Standards

4 Persons

Min Dive Team (L104)

HSE ACOP L104

BS EN 12021

Breathing Air Standard

UK Breathing Air Quality Spec

Annual

Medical Renewal

HSE AMED Regulations

The HSE Surface Supplied Diver qualification requires passing a rigorous theoretical assessment alongside practical dive evaluations. This question bank covers equipment management, site hazards, decompression physics/tables, and emergency procedures. This is an English-language MCQ study adaptation for the official assessment; it does not replace required practical, oral, written, or hands-on performance.

Sample HSE Surface Supplied Diver Practice Questions

Try these sample questions to test your HSE Surface Supplied Diver exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Which component of a surface-supplied commercial diving umbilical serves as the primary mechanical strain relief member to prevent tension on air hoses and cables?

A.Pneumofathometer hose

B.Strength member / lifeline rope

C.Main air supply hose

D.Communications cable

Explanation: The strength member (or dedicated lifeline rope) incorporated into the umbilical bundle absorbs tensile forces and strain during deployment, working, or diver recovery. This prevents structural stress and mechanical damage to gas supply lines and electrical comms wires. The lifeline must meet minimum breaking strength regulations specified by HSE and industry guidelines.

2What is the standard minimum over-bottom gas pressure recommended at the surface control panel above maximum working depth hydrostatic pressure for a demand helmet?

A.1 to 2 bar (15 to 30 psi)

B.25 to 30 bar (360 to 435 psi)

C.15 to 20 bar (220 to 290 psi)

D.6 to 10 bar (90 to 145 psi)

Explanation: Commercial surface-supplied demand helmets (such as Kirby Morgan models) require a regulated surface supply pressure that maintains 6 to 10 bar (approximately 90 to 145 psi) over the ambient water pressure at the diver's depth. This differential accounts for hose friction losses and provides sufficient flow during peak inspiratory effort.

3Under British Standard BS EN 12021 for breathing air quality, what is the maximum allowable concentration of carbon monoxide (CO) in compressed breathing air supplied to a diver?

A.15 ppm

B.5 ppm

C.50 ppm

D.25 ppm

Explanation: BS EN 12021 limits carbon monoxide content in compressed breathing air to a maximum of 5 ppm (parts per million). Because the partial pressure of CO increases with depth under hyperbaric conditions, strict low thresholds are enforced to prevent lethal carbon monoxide poisoning.

4What critical safety function is performed by the non-return check valve fitted to the main gas inlet block of a commercial diving helmet?

A.It prevents catastrophic helmet squeeze by stopping reverse gas flow if umbilical pressure drops

B.It regulates breathing gas pressure down to ambient pressure inside the oral-nasal mask

C.It purges condensation and water buildup out of the breathing loop during heavy exhalation

D.It automatically switches the diver gas supply to the emergency bailout cylinder when line pressure falls

Explanation: The non-return valve (one-way check valve) at the helmet sideblock allows gas to flow only into the helmet. If the main umbilical air supply ruptures or loses pressure, the valve immediately seals to prevent gas backflow, preserving internal helmet pressure and protecting the diver from a fatal barotrauma (squeeze).

5A diver working at a depth of 30 msw (4 bar absolute) requires an emergency bailout gas supply. Assuming a breathing rate of 50 L/min at depth, what minimum usable free air volume must the bailout cylinder contain to ensure 5 minutes of emergency ascent gas?

A.250 L

B.750 L

C.500 L

D.1000 L

Explanation: At 30 msw, hydrostatic pressure is 4 bar absolute (1 bar atmospheric + 3 bar water pressure). At a surface consumption rate of 50 L/min, the equivalent volume rate at depth is 50 L/min × 4 bar = 200 L/min (free air equivalent at surface). For 5 minutes of breathing gas, the required volume is 200 L/min × 5 min = 1000 L of free air.

6How does a surface pneumofathometer system accurately determine a commercial diver's depth?

A.By measuring differential hydraulic fluid displacement between the surface manifold and diver waist unit

B.By calculating acoustic signal travel time bounced from the surface panel transducer down to the diver helmet

C.By purging gas down the pneumo hose until water is displaced, measuring the resulting backpressure at the surface gauge

D.By measuring electrical capacitance changes in an internal sensing wire running inside the umbilical

Explanation: A pneumofathometer operates by purging compressed gas down a dedicated open-ended hose attached to the diver. Once gas bubbles freely out the lower end at the diver's depth, gas flow is throttled back and the backpressure trapped in the line equals the exact hydrostatic water pressure at that depth, which is displayed on a calibrated surface pressure gauge.

7When setting up a diesel-driven low pressure (LP) breathing air compressor on an inshore dive site, where must the air intake pipe be positioned?

A.Upwind of engine exhaust emissions and elevated away from surface toxic contaminants

B.Directly adjacent to the engine cooling fan to ensure cool air intake temperatures

C.Below deck level near the bilge pumps to avoid surface dust

D.Inside an enclosed machinery container to reduce acoustic noise levels

Explanation: Compressor air intakes must be positioned strictly upwind of all combustion engine exhausts (generator, compressor diesel engines, vessel stacks) and elevated above ground level to prevent drawing in toxic carbon monoxide, hydrocarbons, or exhaust fumes into the diver breathing air supply.

8According to commercial diving umbilical construction guidelines, at what regular interval should components (air hose, pneumo, comms, lifeline) be taped or bundled together?

A.Only at both ends near the surface panel and diver helmet

B.Every 10 metres

C.Every 3 to 5 metres

D.Approximately every 1 metre (or 3 feet)

Explanation: Umbilical components are taped or spiral-wrapped together at regular intervals of approximately 1 metre (3 feet). This close binding prevents loops from forming between hoses, reduces snagging hazards, maintains structural integrity, and ensures uniform load distribution along the strength member.

9What is the primary function of the high-pressure (HP) reduction regulator on a surface air control panel?

A.To automatically scrub carbon dioxide out of high-pressure storage cylinders

B.To increase low-pressure compressor output up to 200 bar for cylinder charging

C.To measure the volume of air consumed by the working diver in real time

D.To step down gas pressure from HP storage banks to the required LP over-bottom operating manifold pressure

Explanation: The HP reduction regulator on a dive control panel drops high-pressure reserve gas (e.g. 200–300 bar from HP quad banks) down to low-pressure manifold operating levels (typically 10–18 bar), allowing HP gas to serve as a reliable backup or primary supply to the diver umbilical.

10Where must the diver emergency gas supply (bailout) hose be connected on a Kirby Morgan surface-supplied diving helmet?

A.Into the pneumofathometer quick-disconnect fitting

B.To the rear helmet neck dam locking pin port

C.To the emergency valve (EGS) port on the sideblock assembly

D.Directly into the oral-nasal mask purge valve

Explanation: The emergency bailout hose attaches directly to the Emergency Gas Supply (EGS) valve port on the helmet sideblock assembly. In the event of primary surface supply failure, opening the EGS knob routes high-pressure regulated air from the diver's bailout bottle into the sideblock downstream of the main check valve.

About the HSE Surface Supplied Diver Exam

The HSE Surface Supplied Diver qualification certifies commercial divers in the United Kingdom to perform inland, inshore, and coastal surface-supplied diving operations in compliance with the Diving at Work Regulations 1997 and HSE Approved Codes of Practice (L104). Candidates must master surface equipment operation, umbilical rigging, air supply management, differential pressure mitigation, decompression table calculations, chamber operations, and emergency standby diver response. This is an English-language MCQ study adaptation for the official assessment; it does not replace required practical, oral, written, or hands-on performance.

Assessment

Written theory examination plus practical surface-supplied diving assessment under HSE Diving at Work Regulations. This is an English-language MCQ study adaptation for the official assessment; it does not replace required practical, oral, written, or hands-on performance.

Time Limit

180 minutes

Passing Score

75%

Exam Fee

£1,200 - £3,500 (Course & Assessment) (UK Health and Safety Executive (HSE) Approved Assessment Centres)

HSE Surface Supplied Diver Exam Content Outline

25%

Surface-Supplied Equipment and Umbilical Management

Helmets, bandmasks, surface control panels, air supply compressors, HP/LP gas reserves, bailout bottles, umbilical construction, and strain relief.

25%

Inshore Diving Operations and Site Hazards

Diving at Work Regulations 1997, L104 ACOP, differential pressure (Delta-P), contaminated water, culverts, locks, vessel traffic, and dive team roles.

25%

Decompression Tables and Chamber Operations

DCIEM/HSE decompression schedules, repetitive diving, therapeutic recompression, hyperbaric chamber operation, oxygen safety, and DCS signs.

25%

Emergency Procedures and Standby Diver Duties

Loss of air supply, trapped diver recovery, unconscious diver retrieval, umbilical entanglement, standby diver readiness, and emergency gas switching.

How to Pass the HSE Surface Supplied Diver Exam

What You Need to Know

Passing score: 75%
Assessment: Written theory examination plus practical surface-supplied diving assessment under HSE Diving at Work Regulations. This is an English-language MCQ study adaptation for the official assessment; it does not replace required practical, oral, written, or hands-on performance.
Time limit: 180 minutes
Exam fee: £1,200 - £3,500 (Course & Assessment)

Keys to Passing

Work through all 100 available questions
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HSE Surface Supplied Diver Study Tips from Top Performers

1Memorise the minimum dive team roles and responsibilities set out in the HSE Diving at Work Regulations 1997 and L104 ACOP.

2Practice calculating reserve gas requirements, bailout bottle durations, and compressor air delivery rates at various working depths.

3Understand decompression table rules, including ascent rates, safety stops, surface interval calculations, and repetitive dive factors.

4Rehearse step-by-step emergency responses for loss of surface primary gas, umbilical severance, differential pressure encounters, and standby diver entry.

Frequently Asked Questions

What regulations govern UK commercial surface-supplied diving?

UK commercial surface-supplied diving is governed by the Diving at Work Regulations 1997 (DWR 97) and the associated HSE Approved Code of Practice (ACOP) for Commercial Diving Projects Inland/Inshore (L104).

What is the minimum team size for a surface-supplied diving operation under UK HSE rules?

Under ACOP L104, the standard minimum diving team size for surface-supplied diving is 4 persons: Diving Supervisor, Working Diver, Standby Diver, and Tender/Tender Assistant, though site risk assessment may require additional personnel.

What is the required pass mark for the theoretical examination?

Candidates must achieve at least 75% on the theoretical examination components to pass.

Does this question bank replace practical HSE diver assessment?

No. This is an English-language MCQ study adaptation for the official assessment; it does not replace required practical, oral, written, or hands-on performance.