I85PREP
⌘ K
Cert III Plumbing study materials
Cert III Plumbing study resources

Cert III Plumbing practice questions

One question at a time. Build your Cert III Plumbing understanding.

First 50 of 200 questions. Each one lists the choices, the correct answer, and an explanation. The checker at the top of this page saves progress in this browser when it is available.

Continue in the practice tool above to load more questions, 50 at a time.

Question 1Work health and safety, environmental sustainability and quality requirements

Under work health and safety law, what is the primary duty of a person conducting a business or undertaking (PCBU) on a plumbing site?

  1. To transfer all safety responsibility to the principal contractor in writing
  2. To personally supervise every task performed by every worker at all times
  3. To provide safety equipment only after a worker requests it
  4. To ensure the health and safety of workers and others affected by the work, so far as is reasonably practicable Correct answer.

Explanation

The primary duty of care requires a PCBU to eliminate or minimise risks to the health and safety of workers and other persons affected by the business, so far as is reasonably practicable. This duty cannot be delegated away by contract or transferred to another party.

Question 2Work health and safety, environmental sustainability and quality requirements

A plumber is about to cut into a wall in an older building and notices a meter box nearby. What is the correct first step to manage the risk of electric shock?

  1. Wear rubber-soled boots and proceed with normal cutting methods
  2. Ask the client to switch off the main switch while work proceeds
  3. Isolate and lock out the electrical supply and confirm it is de-energised before work Correct answer.
  4. Cut the wall carefully with hand tools to avoid cables

Explanation

Electrical isolation with lock-out and verification of de-energisation is the required control before penetrating a wall that may contain live cables. Relying on a client or on personal protective equipment alone does not remove the hazard.

Question 3Work health and safety, environmental sustainability and quality requirements

When must a plumber wear hearing protection while using a powered cut-off saw?

  1. Only when another worker is within two metres
  2. Whenever noise exposure is likely to exceed the exposure standard or the area is signposted Correct answer.
  3. Only when the saw is used for more than four hours in a shift
  4. Only when working indoors in an enclosed space

Explanation

Hearing protection is required where noise exposure is likely to exceed the workplace exposure standard or where a noise hazard has been identified and signposted. Exposure depends on level and duration, so a fixed hour threshold is not the test.

Question 4Work health and safety, environmental sustainability and quality requirements

A worker finds a damaged extension lead on site with exposed inner conductors. What is the most appropriate immediate action?

  1. Tag the lead out of service, remove it from the work area and report the defect Correct answer.
  2. Continue using the lead but only for low-power hand tools
  3. Wrap the damaged section with tape and continue using the lead
  4. Ask another worker to hold the lead clear of wet ground

Explanation

Damaged electrical equipment must be withdrawn from service immediately, tagged to prevent use and reported so it can be repaired or replaced. Taping over exposed conductors does not restore the integrity of the lead.

Question 5Work health and safety, environmental sustainability and quality requirements

Which document should a plumber consult to understand the specific safety controls for a task on a large construction site?

  1. The site-specific safe work method statement and relevant risk assessments Correct answer.
  2. The client's building insurance certificate
  3. The council rates notice for the property
  4. The manufacturer's invoice for the plumbing materials

Explanation

Safe work method statements and task-specific risk assessments set out the hazards, controls and sequence of work for high-risk construction activities. They are the documents that translate general duties into site-specific instructions.

Question 6Work health and safety, environmental sustainability and quality requirements

A plumber must enter a confined space such as a sewer maintenance hole. Which control is essential before entry?

  1. Leaving the cover fully open for ventilation and entering alone
  2. Testing the atmosphere and having a stand-by person and rescue plan in place Correct answer.
  3. Relying on the absence of smell as proof the air is safe
  4. Entering quickly to reduce the time spent inside

Explanation

Confined space entry requires atmospheric testing, a stand-by person, communication and a documented rescue plan before anyone enters. Hazardous gases and oxygen deficiency cannot be detected by smell.

Question 7Work health and safety, environmental sustainability and quality requirements

What is the purpose of a hazard identification and risk assessment process before starting a plumbing task?

  1. To satisfy the supplier's warranty conditions
  2. To create paperwork for the client's records only
  3. To identify hazards, evaluate the likelihood and consequence of harm, and decide on controls Correct answer.
  4. To determine the final price of the job

Explanation

Risk assessment identifies hazards and evaluates the likelihood and severity of harm so that controls can be selected and prioritised. The process is a decision-making tool for safety, not a pricing or administrative exercise.

Question 8Work health and safety, environmental sustainability and quality requirements

Under the hierarchy of control, which measure should be considered first for a recurring manual handling hazard when installing a heavy pipe?

  1. Providing training on correct lifting technique
  2. Issuing back braces to the workers
  3. Rotating workers more frequently
  4. Eliminating the hazard by using mechanical lifting equipment or redesigning the task Correct answer.

Explanation

The hierarchy of control ranks elimination and engineering changes above administrative measures and personal protective equipment. Using mechanical lifting or redesigning the task removes or reduces the hazard at its source.

Question 9Work health and safety, environmental sustainability and quality requirements

Which of the following is the correct way to store and handle a compressed gas cylinder on a plumbing site?

  1. Lay the cylinder on its side near the work area for easy access
  2. Leave the regulator attached and the valve open between uses
  3. Store it in a vehicle cabin to prevent theft
  4. Store it upright, secured against falling, away from ignition sources and with the valve closed Correct answer.

Explanation

Compressed gas cylinders must be kept upright and secured so they cannot fall, kept away from heat and ignition sources, and have valves closed when not in use. Correct restraint protects the valve from damage and prevents uncontrolled release.

Question 10Work health and safety, environmental sustainability and quality requirements

How should a plumber manage asbestos risk when renovating a bathroom in a pre-1990 home?

  1. Break up suspect sheeting and place it in general waste
  2. Wet the material and continue removing it without further checks
  3. Assume the material is safe if it is painted over
  4. Stop work, treat suspect material as asbestos and arrange identification and removal by a licensed contractor Correct answer.

Explanation

Suspect asbestos-containing material must be assumed to contain asbestos until identified, and removal work must be done by appropriately licensed contractors under controlled conditions. Disturbing the material without identification risks releasing fibres.

Question 11Work health and safety, environmental sustainability and quality requirements

What is the correct procedure for disposing of waste solder and offcuts containing lead?

  1. Place them in the general construction waste bin
  2. Mix them with soil and spread on the garden
  3. Store them separately and dispose through an approved recycler or hazardous waste service Correct answer.
  4. Bury them on site to avoid transport costs

Explanation

Lead-containing waste must be segregated and sent to an approved recycler or hazardous waste facility to prevent contamination of soil and water. General waste disposal of lead-bearing material breaches environmental obligations.

Question 12Work health and safety, environmental sustainability and quality requirements

A plumber notices a leaking solvent cement container on site. What is the most appropriate environmental response?

  1. Wash the spill into the stormwater drain with water
  2. Cover it with soil so it does not spread
  3. Leave it to evaporate and continue working
  4. Contain the spill with absorbent material, prevent it entering drains and dispose of the absorbent correctly Correct answer.

Explanation

Spills must be contained and prevented from reaching stormwater or soil, then cleaned up and disposed of through the correct waste stream. Stormwater drains flow to waterways untreated, so flushing a spill into them causes pollution.

Question 13Work health and safety, environmental sustainability and quality requirements

Which practice best reduces sediment pollution from a plumbing excavation?

  1. Placing sediment controls such as geotextile barriers around the stockpile and drains Correct answer.
  2. Leaving the excavation open overnight without barriers
  3. Stockpiling excavated soil next to the gutter for later removal
  4. Hosing the site down at the end of each day

Explanation

Sediment controls around stockpiles and drains prevent soil from washing into stormwater during rain. Keeping soil away from gutters and stabilising it are core erosion and sediment control measures.

Question 14Work health and safety, environmental sustainability and quality requirements

What is the purpose of a quality inspection and test plan (ITP) on a plumbing project?

  1. To schedule the delivery of tools to site
  2. To list the materials supplier's contact details
  3. To define the inspection stages, acceptance criteria and sign-off points for the work Correct answer.
  4. To record the hours worked by each plumber

Explanation

An inspection and test plan identifies the checkpoints, methods and acceptance criteria used to verify that work meets specification before it is covered up or handed over. It provides evidence that quality requirements were met at each stage.

Question 15Work health and safety, environmental sustainability and quality requirements

A plumber completes a sanitary drainage installation. Which test is typically performed to verify the pipework is watertight before backfilling?

  1. A smoke test of the water supply line
  2. A pressure or water test of the drainage line with results recorded Correct answer.
  3. A visual check from a distance without access to joints
  4. A check that the pipes are the correct colour

Explanation

Drainage pipework is verified as watertight by an appropriate pressure or water test with results recorded before the trench is backfilled. Testing before backfilling allows any defective joint to be located and repaired.

Question 16Work health and safety, environmental sustainability and quality requirements

Under environmental legislation, what does the precautionary principle generally require of a business?

  1. That action to prevent serious environmental harm is taken even where full scientific certainty is lacking Correct answer.
  2. That environmental costs are always passed to the client
  3. That a business may proceed with any activity until harm is proven in court
  4. That only government agencies must consider environmental risk

Explanation

The precautionary principle supports taking preventative action where there is a risk of serious or irreversible environmental harm, even without complete scientific certainty. It shifts the emphasis toward prevention rather than waiting for proof of damage.

Question 17Work health and safety, environmental sustainability and quality requirements

What should a plumber do before discharging trade waste from a workshop into the sewer?

  1. Check the trade waste agreement and pre-treat or contain waste as required Correct answer.
  2. Discharge it only at night when flows are low
  3. Discharge it directly because the sewer treats all waste
  4. Dilute it with clean water until it looks clear

Explanation

Trade waste discharge is regulated, and businesses must comply with the conditions of their trade waste agreement, including any pre-treatment or containment requirements. Dilution does not change the pollutant load and is not an acceptable control.

Question 18Work health and safety, environmental sustainability and quality requirements

A worker is directed to work at height on a roof to install a vent. Which control should be selected first?

  1. Placing warning signs at ground level
  2. Relying on the worker's experience to avoid falls
  3. Providing a safety harness and lanyard as the only control
  4. Eliminating the need to work at height by pre-assembling or using a guarded platform Correct answer.

Explanation

The hierarchy of control requires eliminating the hazard where possible, then using engineering controls such as guarded platforms or edge protection before relying on personal fall-arrest equipment. Fall arrest is a last line of defence, not a first choice.

Question 19Work health and safety, environmental sustainability and quality requirements

What is the main reason for keeping a site diary that records safety incidents, near misses and environmental observations?

  1. To provide evidence for continuous improvement and legal compliance if an incident is investigated Correct answer.
  2. To calculate worker bonuses
  3. To replace the need for a formal incident notification process
  4. To advertise the business to clients

Explanation

A site diary creates a contemporaneous record that supports incident investigation, demonstrates compliance and informs improvements to controls. It supplements rather than replaces formal notification obligations.

Question 20Work health and safety, environmental sustainability and quality requirements

A plumber is using a two-part epoxy adhesive. Which control best manages the chemical hazard?

  1. Reading the safety data sheet, using gloves and eye protection, and ensuring ventilation Correct answer.
  2. Sniffing the product to confirm it is the right one
  3. Storing both parts together in an unlabelled container
  4. Using the product in a sealed room to keep fumes contained

Explanation

Chemical use requires reference to the safety data sheet, appropriate personal protective equipment and adequate ventilation to control exposure. Unlabelled storage and sniffing the product create additional hazards.

Question 21Work health and safety, environmental sustainability and quality requirements

Why is a job safety analysis (JSA) reviewed with the work crew before a high-risk task begins?

  1. To obtain the client's approval of the quote
  2. To record the crew's qualifications only
  3. To allocate overtime to the crew
  4. To confirm that everyone understands the hazards, controls and their own responsibilities Correct answer.

Explanation

Reviewing the job safety analysis with the crew confirms a shared understanding of hazards, controls and individual responsibilities before work starts. Consultation improves the quality of the controls and the likelihood they are followed.

Question 22Work health and safety, environmental sustainability and quality requirements

A plumber discovers that a subcontractor is working without the required high-risk work licence. What is the appropriate action?

  1. Allow the work to continue because the subcontractor is experienced
  2. Ask the subcontractor to sign a waiver of liability
  3. Stop the work, report the matter to the supervisor and confirm licensing before work resumes Correct answer.
  4. Continue the work but record the issue in the site diary only

Explanation

Unlicensed high-risk work must be stopped and reported so that licensing can be verified before work resumes. A waiver cannot make unlicensed work lawful or remove the risk to safety.

Question 23Work health and safety, environmental sustainability and quality requirements

Which action best demonstrates the quality requirement of 'hold points' in a plumbing installation?

  1. Skipping the inspection if the schedule is behind
  2. Completing all inspections at the end of the project
  3. Proceeding to the next stage as soon as the plumber is satisfied
  4. Pausing work at a defined stage until the required inspection or sign-off is obtained Correct answer.

Explanation

A hold point requires work to stop at a defined stage until the specified inspection or approval is obtained. This prevents defects being covered up and ensures verification occurs before the next stage proceeds.

Question 24Work health and safety, environmental sustainability and quality requirements

A plumber is asked to install a backflow prevention device. What is the primary purpose of this device?

  1. To prevent contaminated water from flowing back into the potable supply Correct answer.
  2. To reduce noise in the pipework
  3. To increase water pressure in the supply line
  4. To measure the volume of water used

Explanation

A backflow prevention device protects the potable water supply by stopping reverse flow of contaminated water into the drinking water system. This is a public health control required by plumbing regulation.

Question 25Plumbing tools, equipment, materials and trade calculations

Which hand tool is specifically designed for cutting internal threads in a pipe or fitting?

  1. A die stock with dies Correct answer.
  2. A pipe wrench
  3. A tube cutter
  4. A flaring tool

Explanation

A die stock holds a threading die that cuts external threads on pipe, while a tap cuts internal threads in a fitting. Threading a pipe end uses a die, and reaming a fitting bore uses a tap. The die stock is the standard hand tool for producing tapered pipe threads on site.

Question 26Plumbing tools, equipment, materials and trade calculations

What is the main purpose of reaming a cut end of copper or steel pipe before assembly?

  1. To mark the insertion depth for soldering
  2. To clean oxide from the outer surface
  3. To taper the outside for easier jointing
  4. To remove the internal burr and restore full bore Correct answer.

Explanation

Cutting pipe leaves a raised burr on the inside edge that restricts flow and can cause turbulence, erosion and noise. Reaming removes this burr and restores the full internal diameter. The outer surface is cleaned separately and insertion depth is marked with a pencil or marker.

Question 27Plumbing tools, equipment, materials and trade calculations

Which material is most commonly specified for sanitary drainage pipe because it is light, corrosion resistant and easily solvent welded?

  1. Cast iron
  2. Galvanised steel
  3. Annealed copper
  4. PVC-U Correct answer.

Explanation

PVC-U is widely used for sanitary drainage because it resists most domestic waste chemicals, is light to handle and joins quickly with solvent cement. Cast iron and galvanised steel are heavier and require mechanical joints or threading. Copper is normally used for supply and heating rather than buried drainage.

Question 28Plumbing tools, equipment, materials and trade calculations

A plumber needs to measure the internal diameter of a copper tube accurately. Which tool is most suitable?

  1. A steel rule
  2. A pipe wrench
  3. A vernier caliper Correct answer.
  4. A spirit level

Explanation

A vernier caliper has internal jaws that measure bore diameter to a fraction of a millimetre. A steel rule cannot reach squarely inside a tube and gives only a rough reading. A spirit level checks alignment and a pipe wrench is for turning fittings.

Question 29Plumbing tools, equipment, materials and trade calculations

What does the nominal size marked on a standard pipe fitting generally refer to?

  1. The approximate bore size used for matching components Correct answer.
  2. The exact outside diameter in millimetres
  3. The maximum working pressure rating
  4. The thread length in millimetres

Explanation

Nominal pipe sizes are a convenient designation close to, but not exactly, the bore. Fittings and pipe of the same nominal size are made to match each other. Actual outside diameter is fixed for each nominal size and is larger than the nominal figure.

Question 30Plumbing tools, equipment, materials and trade calculations

Which safety item must be worn when solvent welding PVC pipe with cement and primer?

  1. A full face respirator
  2. A welding helmet
  3. Chemical-resistant gloves and eye protection Correct answer.
  4. Steel-capped boots only

Explanation

Solvent cement and primer contain volatile solvents that irritate skin and eyes, so chemical-resistant gloves and eye protection are required. Good ventilation is also essential because vapours are flammable and harmful. A welding helmet is for arc welding and gives no chemical protection.

Question 31Plumbing tools, equipment, materials and trade calculations

A copper tube has an outside diameter of 22 mm and a wall thickness of 1.0 mm. What is its approximate internal diameter?

  1. 18 mm
  2. 24 mm
  3. 21 mm
  4. 20 mm Correct answer.

Explanation

Wall thickness occurs on both sides of the tube, so the internal diameter equals outside diameter minus twice the wall thickness. Here 22 mm minus 2 mm gives 20 mm. Forgetting to double the wall thickness is the common error.

Question 32Plumbing tools, equipment, materials and trade calculations

A fall of 1 in 60 is required on a 15 m drain run. What is the total fall?

  1. 150 mm
  2. 300 mm
  3. 900 mm
  4. 250 mm Correct answer.

Explanation

Gradient is expressed as a ratio of fall to run, so fall equals run divided by 60. Converting 15 m to 15000 mm and dividing by 60 gives 250 mm. Multiplying the run by the ratio instead of dividing gives an incorrect, much larger fall.

Question 33Plumbing tools, equipment, materials and trade calculations

What is the purpose of a compression fitting on copper tube?

  1. To join tube by melting solder into the fitting cup
  2. To join tube by tightening a nut that compresses an olive onto the tube Correct answer.
  3. To join tube by solvent cement
  4. To join tube by rolling a groove and clamping a coupling

Explanation

A compression fitting seals by tightening a nut so an olive (ferrule) is crushed onto the outside of the tube. It is a mechanical joint that can be dismantled and needs no heat. Solder joints and solvent-welded joints use entirely different methods.

Question 34Plumbing tools, equipment, materials and trade calculations

Which tool is used to bend soft copper tube without kinking it?

  1. A torque wrench
  2. A hole saw
  3. A pipe wrench
  4. A spring bender or lever bender Correct answer.

Explanation

A bending spring supports the tube wall from inside, or a lever bender supports it from outside, so the tube deforms evenly instead of collapsing. Kinking occurs when tube is bent dry over too small a radius. Neither a hole saw nor a torque wrench has any bending function.

Question 35Plumbing tools, equipment, materials and trade calculations

A tank holds 0.6 cubic metres of water. Approximately how many litres is this?

  1. 6 litres
  2. 600 litres Correct answer.
  3. 6000 litres
  4. 60 litres

Explanation

One cubic metre equals 1000 litres, so 0.6 cubic metres equals 600 litres. Volume in cubic metres is multiplied by 1000 to convert to litres. Moving the decimal the wrong way gives either 6 or 6000 litres.

Question 36Plumbing tools, equipment, materials and trade calculations

Why is a dielectric union used where copper pipe connects to a galvanised steel pipe?

  1. To allow for thermal expansion between the pipes
  2. To break electrical continuity and prevent galvanic corrosion Correct answer.
  3. To increase the flow rate through the joint
  4. To permit the joint to be dismantled without tools

Explanation

Dissimilar metals in contact with an electrolyte form a galvanic cell, and the less noble metal corrodes. A dielectric union places an insulating barrier between the two metals to break that circuit. It has nothing to do with expansion or flow rate.

Question 37Plumbing tools, equipment, materials and trade calculations

What is the standard pressure test method for a newly installed domestic cold water line before it is concealed?

  1. Run a tap for five minutes and observe flow
  2. Test with a smoke test
  3. Fill with water and check for visible drips only
  4. Pressure test with water or air at the specified test pressure for the required duration Correct answer.

Explanation

New supply pipework must be pressure tested at the pressure and for the duration set by the applicable standard before concealment. Visual drip checks miss small leaks that only appear under pressure. Smoke testing is used to locate faults in drainage systems, not to prove supply pipe integrity.

Question 38Plumbing tools, equipment, materials and trade calculations

A pipe run rises 400 mm over a horizontal distance of 8 m. What is the gradient expressed as a ratio?

  1. 1 in 25
  2. 1 in 10
  3. 1 in 20 Correct answer.
  4. 1 in 40

Explanation

Gradient ratio equals the horizontal run divided by the fall. Converting 8 m to 8000 mm and dividing by 400 mm gives 20, so the gradient is 1 in 20. Dividing the fall by the run instead gives a decimal, not the ratio form.

Question 39Plumbing tools, equipment, materials and trade calculations

Which property makes cross-linked polyethylene (PEX) suitable for concealed supply pipework?

  1. It must be threaded at every joint
  2. It can be solvent welded like PVC
  3. It is flexible, resists freezing damage and joins with mechanical fittings Correct answer.
  4. It is only suitable for above-ground drainage

Explanation

PEX is flexible, so it can be routed through walls and ceilings with few fittings, and its cross-linked structure tolerates freezing better than rigid plastics. It is joined with crimp, press or push-fit fittings, never by solvent welding or threading. It is used for supply, not drainage.

Question 40Plumbing tools, equipment, materials and trade calculations

A plumber needs to cut a clean, square end on 100 mm PVC drainage pipe. Which tool is most appropriate?

  1. A plastic pipe saw or ratchet cutter, then deburr Correct answer.
  2. A hacksaw with a fine blade
  3. A wood chisel
  4. An angle grinder with a grinding disc

Explanation

A saw designed for plastics, or a ratchet cutter, produces a square end without excessive heat or shattering, and the burr is then removed. A fine hacksaw can be used but tends to wander and leave an untrue end. A grinding disc generates heat that can soften and distort the pipe.

Question 41Plumbing tools, equipment, materials and trade calculations

A cylindrical cistern has an internal diameter of 500 mm and a water depth of 800 mm. Using pi = 3.14, what is the approximate volume in litres?

  1. 157 litres Correct answer.
  2. 628 litres
  3. 63 litres
  4. 314 litres

Explanation

Volume equals pi times radius squared times depth. The radius is 250 mm, so 3.14 times 62500 times 800 gives about 157000000 cubic millimetres, which is 157 litres. Using the diameter instead of the radius quadruples the answer.

Question 42Plumbing tools, equipment, materials and trade calculations

A hot water line and a cold water line run parallel in a ceiling space. Why must they be separated and the hot line insulated?

  1. To stop the pipes from being electrically earthed
  2. To increase the pressure in the cold line
  3. To allow both pipes to be solvent welded together
  4. To prevent heat transfer to the cold line and reduce energy loss Correct answer.

Explanation

Heat moving from a hot pipe to an adjacent cold pipe warms the cold supply and wastes energy, and can cause condensation on the cold line. Insulating the hot line and maintaining a separation limits this transfer. Earthing, jointing and pressure are unrelated to the separation requirement.

Question 43Plumbing tools, equipment, materials and trade calculations

A drainage stack serving a tall building needs to resist the pressure fluctuations caused by slugs of water falling down it. What is the main function of the vent pipe connected to the stack?

  1. To increase the flow velocity in the stack
  2. To drain condensate from the stack
  3. To equalise air pressure in the system and protect trap seals Correct answer.
  4. To provide a secondary path for waste water

Explanation

Falling water compresses air ahead of it and creates a partial vacuum behind it. A vent admits and releases air so pressures stay near atmospheric, which stops trap seals being sucked out or blown through. Venting does not carry waste or condensate and does not increase velocity.

Question 44Plumbing tools, equipment, materials and trade calculations

During a hydraulic pressure test, a gauge reading of 700 kPa is recorded. Approximately what is this in bar?

  1. 700 bar
  2. 70 bar
  3. 0.7 bar
  4. 7 bar Correct answer.

Explanation

One bar is approximately 100 kPa, so 700 kPa is about 7 bar. Dividing the kilopascal value by 100 converts it to bar. Multiplying instead of dividing gives the much larger 700 bar figure.

Question 45Plans, specifications, drawings and setting out

On a architectural floor plan drawn at a scale of 1:50, a wall measures 84 mm on the drawing. What is the actual length of the wall in metres?

  1. 4.2 m Correct answer.
  2. 42 m
  3. 8.4 m
  4. 0.42 m

Explanation

A scale of 1:50 means one unit on the drawing represents 50 of the same units in reality. Multiplying 84 mm by 50 gives 4200 mm, which converts to 4.2 m by dividing by 1000. Always convert drawing measurements to real units before converting to metres.

Question 46Plans, specifications, drawings and setting out

A site plan is drawn at 1:200. A boundary fence line measures 135 mm on the drawing. What is the real length of the fence?

  1. 67.5 m
  2. 2.7 m
  3. 27 m Correct answer.
  4. 13.5 m

Explanation

At 1:200 each drawing millimetre equals 200 real millimetres. Multiplying 135 mm by 200 gives 27 000 mm, which is 27 m. Converting to metres at the end avoids decimal errors.

Question 47Plans, specifications, drawings and setting out

What does a north point symbol on a construction drawing indicate?

  1. The orientation of the building relative to true or grid north Correct answer.
  2. The fall direction of the roof drainage
  3. The location of the nearest survey benchmark
  4. The direction of prevailing winds for ventilation design

Explanation

A north point establishes orientation so that the drawing can be related to the site and to other drawings. It shows which way north lies relative to the plan, allowing correct setting out and solar or aspect considerations. It does not convey wind, benchmark or drainage information.

Question 48Plans, specifications, drawings and setting out

On a plumbing drawing, what does the abbreviation 'IL' most commonly indicate alongside a level value?

  1. Invert level Correct answer.
  2. Internal line
  3. Inspection lid
  4. Isolation lever

Explanation

Invert level refers to the level of the lowest internal surface of a pipe or drain at a given point. It is a key setting-out value because drainage falls are calculated from invert levels. Other meanings do not match standard drainage notation.

Question 49Plans, specifications, drawings and setting out

Which drawing type would you consult to find the specified pipe material and diameter for a sanitary drainage line?

  1. The sanitary drainage plan and associated specification Correct answer.
  2. The electrical layout drawing
  3. The structural framing plan
  4. The landscape planting plan

Explanation

Pipe sizes and materials are documented on the drainage plan and in the project specification, which together define the installation. Structural, electrical and landscape drawings do not carry plumbing material schedules. Always cross-check the plan against the specification for the governing requirement.

Question 50Plans, specifications, drawings and setting out

A drainage line on a plan is drawn with a fall of 1:60 over a run of 12 m. What is the total fall in millimetres?

  1. 200 mm Correct answer.
  2. 72 mm
  3. 120 mm
  4. 600 mm

Explanation

A gradient of 1:60 means one unit of fall for every 60 units of run. Dividing 12 000 mm by 60 gives 200 mm of total fall. Expressing the run in millimetres keeps the calculation consistent.