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Key Facts: PGDB Certifying Gasfitter Exam

100

Practice Questions

OpenExamPrep

65-70

Exam Questions

PGDB

2.5 hours

Time Limit

PGDB

60%

Passing Score

PGDB

NZ$410

Exam Fee (GST incl)

PGDB

AS/NZS 5601.1:2013

Cited NZ Standard

WorkSafe NZ

The PGDB Certifying Gasfitter Examination is the New Zealand registration exam administered by the Plumbers, Gasfitters and Drainlayers Board for gasfitters seeking certifying (authorised) status. It is computer-based with 65-70 questions over 2.5 hours, about 75% answered electronically and 25% on a paper sheet, and you need 60% to pass; the fee is NZ$410 (GST inclusive) per attempt and reference standards such as AS/NZS 5601.1:2013 are supplied as a PDF in the exam. Content covers AS/NZS 5601 gas installations, LP Gas and natural gas properties, appliance installation and commissioning, flueing and ventilation, gas pressures and pipe sizing, the Gas (Safety and Measurement) Regulations 2010 and certification, soundness/leak testing, and the PGDB Act. The PGDB recommends a minimum of 200 hours of study. This free prep includes 100 research-based practice questions with explanations and an AI tutor.

Sample PGDB Certifying Gasfitter Practice Questions

Try these sample questions to review concepts for the PGDB Certifying Gasfitter exam. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Which standard is cited as the means of compliance with the Gas (Safety and Measurement) Regulations 2010 and NZ Building Code clause G11 for general gas installations in New Zealand?
A.AS/NZS 3000
B.AS/NZS 5601.1
C.AS/NZS 1596
D.NZS 3604
Explanation: AS/NZS 5601.1 (currently the 2013 edition in New Zealand) covers the design, installation and commissioning of general gas installations and is the cited means of complying with the Gas (Safety and Measurement) Regulations 2010 and Building Code clause G11. AS/NZS 5601.2 covers caravans and boats.
2Natural gas is supplied as a 'second family' gas. Approximately what is its relative density compared with air?
A.About 0.6 (lighter than air)
B.About 1.0 (same as air)
C.About 1.5 (heavier than air)
D.About 2.0 (heavier than air)
Explanation: Natural gas (mainly methane) has a relative density of approximately 0.6, making it lighter than air, so leaked natural gas tends to rise and disperse upward. This is a key safety distinction from LP Gas. Ventilation and leak-detection strategies differ accordingly.
3Commercial propane (LP Gas) has a relative density of approximately 1.5. What is the main safety implication of this property?
A.Leaked gas rises quickly to the ceiling
B.Leaked gas tends to settle and pool in low areas
C.It cannot form an explosive mixture
D.It has no odour and cannot be detected
Explanation: Propane has a relative density of about 1.5, so it is heavier than air and a leak tends to flow downhill and collect in low-lying areas such as pits, drains, basements and trenches. This is why LP Gas appliances and cylinders require low-level ventilation and why pits near LP Gas are hazardous.
4What is the approximate flammability (explosive) range of natural gas in air?
A.2% to 10%
B.5% to 15%
C.1% to 6%
D.10% to 25%
Explanation: Natural gas (methane) has a lower explosive limit (LEL) of about 5% and an upper explosive limit (UEL) of about 15% by volume in air. Within this band an ignition source can cause an explosion; below the LEL the mixture is too lean and above the UEL too rich to ignite.
5Approximately what is the flammable range of LP Gas (propane) in air?
A.5% to 15%
B.2% to 10%
C.4% to 75%
D.0.5% to 3%
Explanation: Propane has a lower explosive limit of roughly 2% and an upper explosive limit of roughly 10% by volume in air. Its narrower, lower range compared with natural gas means a relatively small leak can quickly reach an explosive concentration in a confined low space.
6Which product of incomplete combustion of a gas appliance is the toxic, odourless gas most dangerous to occupants?
A.Carbon dioxide
B.Carbon monoxide
C.Water vapour
D.Nitrogen
Explanation: Carbon monoxide (CO) is produced when there is insufficient air for complete combustion. It is colourless and odourless and binds to haemoglobin far more readily than oxygen, causing poisoning. Correct aeration, flueing and ventilation are designed to prevent its accumulation indoors.
7A correctly adjusted gas burner producing complete combustion will typically show what flame appearance?
A.Lazy yellow flame
B.Crisp blue flame with defined inner cones
C.Orange flame with soot
D.Smoky red flame
Explanation: Complete combustion of a gas burner produces a clean, crisp blue flame with well-defined inner cones, indicating the correct air-to-gas ratio. Yellow, orange or sooty flames indicate incomplete combustion from insufficient primary aeration and the potential for carbon monoxide production.
8Under AS/NZS 5601.1, when testing a consumer piping installation for soundness, the test pressure must be at least operating pressure or what minimum value, whichever is greater?
A.0.5 kPa
B.2.0 kPa
C.7.0 kPa
D.70 kPa
Explanation: AS/NZS 5601.1 requires the consumer piping to be pressurised to the operating pressure or 2.0 kPa, whichever is greater, and held so that no pressure loss is observed over the specified test period (typically 5 minutes for the test). This confirms the installation is gastight before connecting appliances.
9Which instrument is most appropriate for measuring the low operating pressure of a domestic gas appliance during commissioning?
A.Bourdon tube gauge reading in MPa
B.Water or electronic manometer reading in kPa
C.Vacuum gauge
D.Megohmmeter
Explanation: Domestic appliance operating pressures are very low (around 1 to 3 kPa), so a manometer — a water-column (U-tube) or electronic digital manometer reading in kPa or millibar — gives the resolution needed. A high-range Bourdon gauge in MPa cannot resolve such small pressures accurately.
10An installation pipe-sizing calculation must ensure that the pressure drop from the meter/regulator to the most remote appliance does not exceed what is permitted. The principal reason for limiting pressure drop is to ensure:
A.The pipe does not corrode
B.Each appliance receives adequate gas pressure and rate
C.The gas remains odourised
D.The meter index reads correctly
Explanation: Pipe sizing limits the pressure drop so that every appliance, even the most remote, receives sufficient pressure and gas flow rate to operate correctly at its rated input. Excessive pressure drop starves appliances, causing poor combustion, lifting/flame failure and underperformance.

About the PGDB Certifying Gasfitter Exam

The PGDB Certifying Gasfitter Examination is New Zealand's registration exam for gasfitters seeking certifying (authorised) status. The computer-based exam has 65-70 questions over 2.5 hours, with about 75% answered electronically and 25% on a paper sheet, and requires 60% to pass. AS/NZS 5601 and other reference standards are supplied as a PDF within the exam.

Exam sponsor: Plumbers, Gasfitters and Drainlayers Board (PGDB). The requirements and fees below concern the certification or admission exam, separate from our free practice resources.

Assessment

65-70 questions over 2.5 hours, computer-based with about 75% electronic (multiple-choice, inline selection, numerical, multi-select) and 25% paper-based (drawing/design on diagrams), 60% to pass; reference standards including AS/NZS 5601 are supplied as a PDF. This practice bank is 100 selected-response items.

Time Limit

2.5 hours

Passing Score

60%

Exam / Certification Fees

NZ$410.00 (GST inclusive) per attempt

Exam sponsor website

Fees, eligibility, and exam policies can change. Confirm them with the exam sponsor before applying or paying.

Our practice resources: topics covered

We aim to reflect publicly available exam outlines and topic information in our study resources. Coverage, format, and difficulty may differ from the actual exam, and we cannot guarantee that every detail is accurate or current. Confirm exam requirements, fees, and policies with the official exam sponsor.

18%

AS/NZS 5601 Gas Installations

AS/NZS 5601.1:2013 for installation, pipe materials and jointing, supports, sleeving, buried piping, isolation valves and appliance location rules

17%

LP Gas & Natural Gas Properties

Relative density, calorific value, Wobbe index, flammable limits, odorisation, combustion air, LP Gas vaporisation and gas interchangeability

18%

Appliance Installation & Commissioning

Commissioning sequence, purging, operating-pressure setting, clocking the meter, flame condition, flame-failure devices, ignition and gas conversion

17%

Flueing & Ventilation

Open-flued, room-sealed and flueless appliances, flue sizing and clearances, draught and spillage testing, and combustion-air ventilation

13%

Gas Pressures & Pipe Sizing

Operating pressures, regulators and two-stage regulation, pressure-drop limits, gas-rate calculations and pipe sizing

10%

NZ Gas Regulations & Certification

Gas (Safety and Measurement) Regulations 2010, CoC and GSC, general vs high-risk gasfitting, point of supply and WorkSafe NZ

5%

Leak & Soundness Testing

Soundness/pressure testing, leak detection, purging on commissioning and decommissioning, and leak rectification

2%

PGDB Act & Trade Regulation

Plumbers, Gasfitters, and Drainlayers Act 2006, registration classes, certifying authority, practising licences and continuing competence

Preparing for the PGDB Certifying Gasfitter Exam

What You Need to Know

  • Passing score: 60%
  • Assessment: 65-70 questions over 2.5 hours, computer-based with about 75% electronic (multiple-choice, inline selection, numerical, multi-select) and 25% paper-based (drawing/design on diagrams), 60% to pass; reference standards including AS/NZS 5601 are supplied as a PDF. This practice bank is 100 selected-response items.
  • Time limit: 2.5 hours
  • Exam / certification fees: NZ$410.00 (GST inclusive) per attempt Official sources

Using Our Practice Resources

  • Work through all 100 available questions
  • Review every answer and explanation
  • Track weak areas and revisit them
  • Use our AI tutor for tough concepts

PGDB Certifying Gasfitter: Suggested Study Strategy

1Know AS/NZS 5601.1:2013 well and practise finding clauses fast, the standard is supplied in the exam but time is tight
2Memorise key gas properties: natural gas relative density about 0.6 and CV about 38 MJ/m3; propane about 1.5 and CV about 96 MJ/m3
3Learn the soundness test rule (operating pressure or 2.0 kPa, whichever is greater) and the commissioning sequence: test, purge, light, set pressure, check combustion
4Practise gas-rate and pressure-drop calculations: gas rate equals MJ/h divided by calorific value, used when clocking the meter and sizing pipe
5Distinguish a Certificate of Compliance from a Gas Safety Certificate and know who issues each under the Gas (Safety and Measurement) Regulations 2010
6Complete all 100 practice questions and review every miss with the AI tutor, then prepare for the paper-based drawing/design section separately

Frequently Asked Questions

How many questions are on the PGDB Certifying Gasfitter exam and how long is it?

The certifying gasfitter examination has 65 to 70 questions and runs for 2.5 hours. It is computer-based, with about 75% of questions answered electronically and 25% on a paper sheet, and you need 60% to pass.

What score do I need to pass the certifying gasfitter exam?

You need 60% to pass the PGDB certifying gasfitter examination. Reference standards including AS/NZS 5601 are supplied as a PDF within the exam, but you must know how to apply them quickly under time pressure.

How much does the PGDB certifying gasfitter exam cost?

The certifying gasfitter examination fee is NZ$410.00 (GST inclusive) per attempt, booked through the Plumbers, Gasfitters and Drainlayers Board. PGDB registration and practising-licence fees are separate.

What does the certifying gasfitter exam cover?

It covers AS/NZS 5601 gas installations, LP Gas and natural gas properties, appliance installation and commissioning, flueing and ventilation, gas pressures and pipe sizing, the Gas (Safety and Measurement) Regulations 2010 and certification, leak and soundness testing, and the PGDB Act.

Which edition of AS/NZS 5601 does the exam use?

In New Zealand the 2013 edition of AS/NZS 5601.1 remains the cited means of complying with the Gas (Safety and Measurement) Regulations 2010 and Building Code clause G11, so candidates should study and answer to the 2013 edition.

Is this free certifying gasfitter practice as good as paid prep?

Our 100 practice questions cover the same content areas as the certifying examination, with a teaching explanation for every answer plus free daily AI tutor interactions. All content is free forever and updated for 2026.