100+ Free HSE Surface Supplied Top-Up Practice Questions

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2026 Statistics

Key Facts: HSE Surface Supplied Top-Up Exam

100 MCQs

Practice Questions

HSE Offshore Diving Syllabus

180 Mins

Time Limit

HSE Assessment Guidelines

75%

Passing Score

HSE Commercial Diving Standards

5 Mins

Max SurDO2 Surface Interval

HSE ACOP L103 / IMCA SurDO2

5 Metres

Min Clearance to DP Thrusters

IMCA D 010 / HSE Offshore

Annual

Medical Renewal

HSE AMED Regulations

The HSE Surface Supplied Top-Up qualification requires passing a rigorous theoretical assessment alongside practical offshore dive evaluations. This question bank covers offshore dive safety, wet bell LARS operations, SurDO2 hyperbaric protocols, and DP vessel diving safeguards. 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 Top-Up Practice Questions

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

1Which United Kingdom statutory regulation and associated Approved Code of Practice (ACOP) specifically govern offshore commercial surface-supplied diving operations?

A.The Diving at Work Regulations 1997 and HSE ACOP L103 (Commercial Diving Projects Offshore)

B.The Diving at Work Regulations 1997 and HSE ACOP L104 (Commercial Diving Projects Inland/Inshore)

C.The Health and Safety at Work etc. Act 1974 and Offshore Installations Order 2005

D.The Pressure Systems Safety Regulations 2000 and ACOP L108

Explanation: Offshore commercial surface-supplied diving operations in the UK are regulated under the Diving at Work Regulations 1997 (DWR 97) and supported by HSE ACOP L103 ('Commercial Diving Projects Offshore'). ACOP L104 applies strictly to inland and inshore commercial diving operations.

2What is the critical safety function of the non-return valve (check valve) fitted to the air inlet manifold of a surface-supplied commercial diving helmet or bandmask?

A.It prevents catastrophic helmet depressurization and squeeze if the main supply umbilical is severed or depressurized

B.It diverts exhaled air directly into the hot water suit to maintain thermal insulation

C.It automatically regulates breathing gas supply pressure to match ambient water depth

D.It isolates the reserve bailout cylinder from the surface supply manifold during normal diving operations

Explanation: The non-return valve on a diver's helmet or bandmask permits air flow only into the helmet. If the surface supply umbilical is cut, severed, or loses pressure, the valve closes instantly, preventing the high ambient water pressure from sucking air out of the helmet and causing fatal thoracic/cranial squeeze.

3What is the standard temperature range for hot water delivered from the surface heating unit to a diver's hot water suit during deep offshore surface-supplied diving?

A.25°C to 30°C (77°F to 86°F)

B.48°C to 55°C (118°F to 131°F)

C.38°C to 42°C (100°F to 108°F)

D.60°C to 65°C (140°F to 149°F)

Explanation: Hot water suits receive heated sea water maintained between 38°C and 42°C at the diver's manifold to protect against hypothermia without scalding the skin. Temperatures above 45°C cause thermal burns, while temperatures below 35°C fail to maintain core thermal equilibrium in cold offshore waters.

4What is the primary function of a Kellems grip (mesh strain relief sleeve) fitted to a diver's umbilical at the harness attachment point?

A.To serve as a secondary lifting point for recovering an unconscious diver to the deck without a harness

B.To transfer pulling tension from the umbilical directly to the diver's harness, protecting gas line fittings from strain

C.To clamp the hot water hose to the communication cable to prevent thermal heat loss along the umbilical

D.To lock the pneumofathometer tube to the primary air hose to prevent acoustic noise interference

Explanation: A Kellems grip (wire mesh strain relief) grips the outer bundle of the umbilical and attaches securely to a heavy D-ring on the diver's safety harness. This ensures mechanical strain or pulling forces are absorbed by the harness rather than pulling on fragile gas hose fittings or electrical comms connectors.

5Under commercial diving safety standards, what is the maximum permissible depth measurement tolerance for a pneumofathometer gauge used on an offshore surface control panel?

A.Accurate within ± 5.0 metres (± 16.4 feet) for dives up to 50 metres depth

B.Accurate within ± 0.25 metres (± 0.8 feet) or 0.5% of full scale

C.Accurate within ± 2.0 metres (± 6.5 feet) across all operating depths

D.Accurate within ± 10.0% of the maximum measurable panel pressure

Explanation: Pneumofathometers are precision gauges critical for decompression tracking and must be calibrated to high accuracy standards, typically within ± 0.25 metres (or 0.5% of full scale deflection), and re-calibrated at least every 6 months under HSE and IMCA requirements.

6Under HSE ACOP L103, who holds ultimate operational responsibility for the planning, safe execution, and supervisory control of an offshore surface-supplied diving operation?

A.The Working Diver performing the subsea task

B.The Master (Captain) of the Diving Support Vessel

C.The Client Representative onboard the vessel

D.The appointed Diving Supervisor

Explanation: Under the Diving at Work Regulations 1997 and ACOP L103, the appointed Diving Supervisor has absolute legal and operational responsibility for the safety of the diving operation and all personnel in the dive team. While the Vessel Master holds overall command of the vessel, the Supervisor controls diving activity.

7What is the minimum typical pressure rating and cylinder capacity for a diver's emergency bailout bottle used in offshore surface-supplied diving?

A.10 to 12 litres water capacity rated to 200 or 300 bar working pressure

B.50 litres water capacity rated to 50 bar working pressure

C.2 litres water capacity rated to 100 bar working pressure

D.3 litres water capacity rated to 150 bar working pressure

Explanation: Offshore surface-supplied divers carry emergency bailout cylinders typically sized between 10 and 12 litres water capacity charged to 200–300 bar. This ensures sufficient emergency breathing gas for the diver to reach the wet bell or surface from maximum excursion depth.

8Which standard specifies breathing air purity requirements (maximum limits for CO, CO2, oil mist, and water vapour) for commercial diving in UK waters?

A.BS EN 250 (Open-circuit self-contained compressed air diving apparatus)

B.BS EN 12021 (Respiratory equipment — Compressed gases for breathing apparatus)

C.IMCA M 103 (Guidelines for the Design and Operation of DP Vessels)

D.ISO 9001 (Quality Management Systems)

Explanation: BS EN 12021 specifies compressed breathing gas purity standards in the UK and Europe, establishing strict maximum limits for carbon monoxide (5 ppm), carbon dioxide (500 ppm), oil mist (0.5 mg/m³), and water vapor.

9What is the mandatory minimum dive team structure required under HSE ACOP L103 for an offshore surface-supplied diving operation conducted from a vessel?

A.Minimum 5 persons: Diving Supervisor, Working Diver, Standby Diver, Tender, and Deck/Chamber Tender

B.Minimum 3 persons: Diving Supervisor, Working Diver, and Standby Diver

C.Minimum 10 persons including 4 working divers simultaneously in the water

D.Minimum 2 persons: Diving Supervisor and Working Diver

Explanation: Under ACOP L103, offshore surface-supplied diving operations require a minimum team of 5 qualified individuals: Diving Supervisor, Working Diver, Standby Diver, Tender for Working Diver, and Tender/Chamber Operator. Site risk assessment frequently increases this number.

10Under BS EN 12021 standards for offshore diving breathing air, what is the maximum allowable concentration of carbon monoxide (CO)?

A.50 ppm

B.100 ppm

C.25 ppm

D.5 ppm (parts per million)

Explanation: BS EN 12021 mandates a maximum carbon monoxide limit of 5 ppm in compressed breathing air. Because partial pressure increases with depth, even tiny CO concentrations become toxic under hyperbaric conditions.

About the HSE Surface Supplied Top-Up Exam

The HSE Surface Supplied Top-Up qualification certifies commercial divers in the United Kingdom to perform offshore surface-supplied diving operations from vessels, wet bells, and dynamic positioning platforms in compliance with the Diving at Work Regulations 1997 and HSE Approved Code of Practice L103. Candidates must demonstrate thorough knowledge of offshore surface gas manifolds, hot water suits, wet bell LARS deployment, surface decompression with oxygen (SurDO2) timing and chamber operations, and physical umbilical restriction rules on DP vessels. 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 offshore surface-supplied diving assessment (wet bell, SurDO2, DP vessel operations) 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

£1,800 - £4,500 (Course & Assessment) (UK Health and Safety Executive (HSE) Approved Assessment Centres)

HSE Surface Supplied Top-Up Exam Content Outline

25%

Offshore Surface-Supplied Diving Operations

ACOP L103 regulations, offshore dive team roles, hot water suits, gas manifolds, primary/secondary HP supply quads, bailout systems, and diver communications.

25%

Wet Bell Operations and Launch & Recovery Systems

Wet bell dome air management, internal emergency gas cylinders, LARS winch man-riding certification, guide wire tensioners, excursion limits, and bell emergency ascent.

25%

Surface Decompression with Oxygen (SurDO2)

SurDO2 protocols, 5-minute maximum surface transfer window, DDC chamber pressurization, BIBS oxygen delivery, overboard dumps, O2 toxicity monitoring, and air breaks.

25%

Dynamic Positioning (DP) Vessel Diving Safety

IMCA D 010 guidelines, physical umbilical stopping/restraints against thruster hazards, DP status lights (Green, Amber, Red), standby diver bell positioning, and run-off/drift-off emergency aborts.

How to Pass the HSE Surface Supplied Top-Up Exam

What You Need to Know

Passing score: 75%
Assessment: Written theory examination plus practical offshore surface-supplied diving assessment (wet bell, SurDO2, DP vessel operations) 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: £1,800 - £4,500 (Course & Assessment)

Keys to Passing

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HSE Surface Supplied Top-Up Study Tips from Top Performers

1Memorise the exact requirements of HSE ACOP L103 for offshore surface-supplied dive teams and minimum staffing levels.

2Master the physical mechanics and emergency systems of Wet Bell LARS, including man-riding winch rules and guide-wire secondary recovery.

3Understand all phases of Surface Decompression with Oxygen (SurDO2), paying strict attention to the 5-minute surface interval limit, chamber BIBS operation, and oxygen toxicity safeguards.

4Rehearse DP vessel diving safety rules, including physical umbilical length calculation (distance to nearest thruster minus 5m safety margin) and DP light status responses.

Frequently Asked Questions

What is the purpose of the HSE Surface Supplied Top-Up qualification?

The HSE Surface Supplied Top-Up upgrades a surface-supplied inland/inshore commercial diver (Part 3) to full offshore surface-supplied status (ACOP L103), qualifying them to work from offshore diving support vessels, barges, and platforms using wet bells, SurDO2, and DP systems.

What regulations and guidelines govern UK offshore surface-supplied diving?

Offshore diving in the UK is governed by the Diving at Work Regulations 1997 (DWR 97), HSE Approved Code of Practice L103 (Commercial Diving Projects Offshore), and IMCA International Codes of Practice (such as IMCA D 014 and IMCA D 010).

What is the maximum allowed surface interval during a SurDO2 procedure?

Under standard HSE and IMCA SurDO2 procedures, the maximum time allowed from when the diver leaves the in-water decompression stop depth to being pressurized on 100% oxygen in the deck decompression chamber (DDC) is 5 minutes.

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.