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Plumbing NC II study materials
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Plumbing NC II practice questions

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Question 1Occupational Health and Safety (OHS) and housekeeping procedures

Under the Philippine OSH framework applied to plumbing worksites, who is primarily responsible for ensuring that workers are provided with appropriate personal protective equipment at no cost to them?

  1. The materials supplier
  2. The employer Correct answer.
  3. The building tenant
  4. The plumbing apprentice

Explanation

Occupational safety and health rules place the duty of providing and maintaining PPE on the employer, who must issue it free of charge and ensure it fits and functions properly. Workers have a duty to use the equipment, but they are not the ones obligated to procure it.

Question 2Occupational Health and Safety (OHS) and housekeeping procedures

A plumber must cut galvanized iron pipe with a power hacksaw in an enclosed utility room. Which PPE combination best matches the hazards of that specific task?

  1. Welding helmet and leather apron
  2. Dust mask and cotton gloves
  3. Safety goggles and hearing protection Correct answer.
  4. Rubber boots and a raincoat

Explanation

Power cutting of metal pipe throws metal chips and generates high noise, so eye protection against flying fragments and hearing protection against the saw's noise are the controlling items. The other combinations address hazards that this cutting task does not present.

Question 3Occupational Health and Safety (OHS) and housekeeping procedures

Before entering an excavation for a below-slab drainage connection, a plumber notices the walls are vertical, unsupported, and the soil is loose. What is the correct immediate action?

  1. Enter quickly to finish before collapse
  2. Refuse entry until shoring or sloping is installed Correct answer.
  3. Place a ladder and enter with a hard hat only
  4. Ask a co-worker to watch from the top

Explanation

An unsupported vertical cut in loose soil is a cave-in hazard, and no worker should enter until the excavation is sloped, shored, or otherwise made safe. A hard hat or a spotter does not prevent the walls from collapsing onto the worker.

Question 4Occupational Health and Safety (OHS) and housekeeping procedures

Which practice correctly applies lockout/tagout when a plumber repairs a jammed submersible pump in a sump pit?

  1. Isolate the circuit, lock the disconnect, and verify zero energy Correct answer.
  2. Tape a warning note over the pump starter
  3. Unplug the pump and leave the plug nearby
  4. Switch off the breaker and tell a co-worker

Explanation

Lockout/tagout requires isolating the energy source, applying a personal lock and tag, and verifying that the equipment is de-energized before work begins. Verbal notice, unplugging without control, or a paper note alone does not prevent another person from restoring power.

Question 5Occupational Health and Safety (OHS) and housekeeping procedures

In plumbing housekeeping, what is the standard way to store lengths of PVC pipe and steel pipe on a construction site to control hazards?

  1. Leaned loosely against a wall
  2. Stacked horizontally on racks with chocks Correct answer.
  3. Laid across a walkway for quick access
  4. Piled vertically in a corner

Explanation

Long pipe should be stored horizontally on racks or dunnage and secured with chocks so it cannot roll or topple. Leaning or vertical stacking creates a falling-load hazard, and blocking a walkway creates a trip hazard.

Question 6Occupational Health and Safety (OHS) and housekeeping procedures

A plumber is about to solder copper joints in a basement where a solvent-based primer was just used. Which hazard control is most important before lighting the torch?

  1. Wetting the floor around the work area
  2. Opening a nearby water valve
  3. Ventilating the space and removing flammable materials Correct answer.
  4. Wearing a dusk mask and safety glasses

Explanation

Solvent primers and fluxes release flammable vapors, and open flame soldering can ignite them, so the area must be ventilated and combustibles removed before hot work. Wetting the floor or opening a valve does not address the vapor ignition risk.

Question 7Occupational Health and Safety (OHS) and housekeeping procedures

When using a portable grinder to deburr a cast-iron soil pipe, which housekeeping practice reduces the risk of a fire in the work area?

  1. Spraying water over the grinder
  2. Sweeping sparks into a corner
  3. Storing oily rags beside the workbench
  4. Keeping combustible scrap and rags away from the spark zone Correct answer.

Explanation

Grinding produces hot sparks that can ignite nearby combustibles, so scrap, rags, and other flammable material must be cleared from the spark path. Oily rags and accumulated debris are common ignition sources that should be removed from the area.

Question 8Occupational Health and Safety (OHS) and housekeeping procedures

A plumber must work inside a newly installed septic tank to seal a pipe penetration. Which control is required before entry?

  1. Entering with a flashlight after a short wait
  2. Testing the atmosphere and providing forced ventilation Correct answer.
  3. Asking a co-worker to call every ten minutes
  4. Wearing a dust mask and safety boots

Explanation

A septic tank is a confined space that can accumulate hydrogen sulfide and other toxic or oxygen-displacing gases, so the atmosphere must be tested and ventilated before and during entry. A dust mask offers no protection against toxic gases or oxygen deficiency.

Question 9Occupational Health and Safety (OHS) and housekeeping procedures

Which is the correct procedure for handling a leaking container of PVC solvent cement found in the site storage area?

  1. Pour the remaining cement into a water drain
  2. Seal the leak, label the container, and move it to a ventilated storage area Correct answer.
  3. Leave it open so the solvent evaporates
  4. Store it next to the welding gas cylinders

Explanation

Solvent cement is flammable and emits harmful vapors, so a leaking container must be contained, labeled, and kept in a ventilated, fire-safe storage area. Pouring it into a drain pollutes water, and leaving it open releases flammable vapor into the workplace.

Question 10Occupational Health and Safety (OHS) and housekeeping procedures

On a plumbing site, what is the primary purpose of a toolbox talk or safety briefing held before the day's work?

  1. To review the day's hazards and required controls Correct answer.
  2. To record the number of pipes installed
  3. To assign overtime pay
  4. To inspect delivered materials

Explanation

A toolbox talk is a short pre-task briefing that identifies the specific hazards of the day's work and confirms the controls and responsibilities. It is not a payroll, procurement, or production-tracking activity.

Question 11Occupational Health and Safety (OHS) and housekeeping procedures

A plumber must manually carry a 50 kg cast-iron pipe section a short distance. Which approach best applies manual handling principles?

  1. Use a mechanical aid or two-person team lift and keep the load close Correct answer.
  2. Carry it on one shoulder for balance
  3. Drag it quickly to reduce carrying time
  4. Lift with the back bent and twist while walking

Explanation

Loads beyond a safe individual limit should be moved with a mechanical aid or a team lift, keeping the load close to the body to reduce spinal strain. Bending the back, twisting, or shouldering a heavy pipe sharply increases the risk of back and shoulder injury.

Question 12Occupational Health and Safety (OHS) and housekeeping procedures

When working on a roof to install a vent stack, which fall-protection measure is appropriate?

  1. Tying a rope around the waist to a vent pipe
  2. Relying on a co-worker to hold the ladder
  3. Working barefoot for better grip
  4. Wearing a safety harness anchored to a secure point Correct answer.

Explanation

Roof work at height requires fall protection such as a full-body harness anchored to a certified secure point, plus guardrails or edge protection where possible. Improvised rope ties or a ladder holder do not provide reliable fall arrest.

Question 13Occupational Health and Safety (OHS) and housekeeping procedures

What is the correct housekeeping action at the end of a plumbing shift regarding tools and leftover materials?

  1. Stack scrap pipe in the nearest exit doorway
  2. Leave tools where they were used for the next shift
  3. Wash tools in the drinking water container
  4. Return tools to storage and clear scrap and debris from walkways Correct answer.

Explanation

End-of-shift housekeeping means returning tools to their designated storage and removing scrap and debris from walkways and work areas. Leaving tools scattered or blocking exits creates trip and egress hazards for the next shift.

Question 14Occupational Health and Safety (OHS) and housekeeping procedures

A plumber is using a chemical drain cleaner in a bathroom with poor airflow. Which combination of controls best protects the worker?

  1. Open the door and wear a dust mask
  2. Work quickly and hold your breath
  3. Read the SDS, ventilate the area, and wear chemical-resistant gloves and eye protection Correct answer.
  4. Add another chemical to speed up the reaction

Explanation

Chemical drain cleaners are corrosive and can release irritating fumes, so the safety data sheet must be reviewed, the space ventilated, and gloves and eye protection worn. Holding one's breath or adding another chemical does not control exposure and can create dangerous reactions.

Question 15Occupational Health and Safety (OHS) and housekeeping procedures

Which action correctly follows the hierarchy of controls when a plumbing crew must reduce exposure to silica dust from cutting concrete pipe?

  1. Rotate workers every hour
  2. Use a wet-cutting method or dust extraction before relying on respirators Correct answer.
  3. Issue respirators as the first and only measure
  4. Post a warning sign at the cutting area

Explanation

The hierarchy of controls prioritizes eliminating or reducing the hazard at the source, so wet cutting or dust extraction comes before PPE such as respirators. Signs and rotation are administrative measures that do not reduce the amount of dust generated.

Question 16Occupational Health and Safety (OHS) and housekeeping procedures

A plumber finds a damaged 3-core extension cord with exposed inner wires being used to power a pipe threader. What is the safest immediate response?

  1. Use it only for low-power tools
  2. Wrap the exposed section with ordinary tape and continue
  3. Remove the cord from service and tag it for repair or replacement Correct answer.
  4. Plug it into a different outlet

Explanation

A cord with exposed conductors is a shock and fire hazard and must be taken out of service, tagged, and repaired or replaced by a competent person. Taping or restricting its use does not restore the insulation integrity required for safe operation.

Question 17Occupational Health and Safety (OHS) and housekeeping procedures

In plumbing work, why should a gas-fired soldering torch be shut off and its cylinder removed from the work area before leaving for a break?

  1. To prevent accidental ignition and unauthorized use during absence Correct answer.
  2. To allow the torch to cool faster
  3. To reduce the weight of the tool bag
  4. To save on fuel consumption

Explanation

An unattended live torch can be ignited by nearby sparks or used by unauthorized persons, so the fuel supply must be shut off and the cylinder removed before leaving. Fuel savings or cooling speed are not the safety reason for this practice.

Question 18Occupational Health and Safety (OHS) and housekeeping procedures

A plumber is working in a trench and a co-worker begins operating a jackhammer nearby, creating loud noise and flying debris. Which is the best combined response?

  1. Continue working and shout to communicate
  2. Cover ears with hands while working
  3. Wear hearing protection and eye protection, and keep a safe distance from the jackhammer Correct answer.
  4. Ask the co-worker to stop permanently

Explanation

The jackhammer creates both a noise hazard and a flying-debris hazard, so hearing and eye protection are needed and the worker should maintain distance from the impact zone. Shouting or covering ears with hands does not provide adequate protection.

Question 19Occupational Health and Safety (OHS) and housekeeping procedures

An apprentice reports dizziness and headache while using solvent cement in a small unventilated closet. What is the correct first action?

  1. Open the container wider to let fumes escape
  2. Give the apprentice water and continue work
  3. Ask the apprentice to finish the joint quickly
  4. Move the apprentice to fresh air and seek medical evaluation Correct answer.

Explanation

Dizziness and headache after solvent exposure suggest inhalation of solvent vapor, so the affected worker must be moved to fresh air and medically evaluated. Continuing work in the same space risks more serious exposure and possible unconsciousness.

Question 20Occupational Health and Safety (OHS) and housekeeping procedures

Why is it important to keep a first-aid kit and an emergency contact list at a plumbing worksite?

  1. To satisfy a client's decoration requirements
  2. To enable prompt treatment and summoning of help after an injury Correct answer.
  3. To replace the need for PPE
  4. To store small plumbing fittings

Explanation

A stocked first-aid kit and current emergency contacts allow immediate basic treatment and rapid summoning of medical help after an injury. They supplement, but never replace, hazard controls and PPE on site.

Question 21Interpretation of technical drawings, plans, and specifications

On a sanitary drainage plan, a pipe run is labeled with a slope written as "1:50". What does this notation mean for the installer?

  1. The pipe diameter tapers from 50 mm down to 1 mm at the outlet
  2. The pipe falls 1 unit vertically for every 50 units of horizontal run Correct answer.
  3. The pipe rises 50 mm for every 1 m of run
  4. The pipe must be installed at a 50-degree angle to the floor

Explanation

A ratio slope such as 1:50 expresses fall per unit of horizontal length, so the drain drops one unit for every fifty units along the run. This is equivalent to a 2 percent grade and is used on drawings to keep drainage self-cleaning without excessive velocity.

Question 22Interpretation of technical drawings, plans, and specifications

A floor plan carries the note "W.C. - 100 mm Ø, centerline 300 mm from finished wall". Which setting-out dimension does the plumber mark before roughing in?

  1. The distance from the wall face to the center of the water closet drain Correct answer.
  2. The height of the flush valve above the floor
  3. The depth of the trap below the finished floor
  4. The width of the water closet fixture base

Explanation

A centerline dimension locates the axis of the pipe or fixture relative to a stated reference, here the finished wall. The plumber sets out the drain center at 300 mm from that wall so the fixture lands correctly.

Question 23Interpretation of technical drawings, plans, and specifications

In a plumbing drawing title block, what is the purpose of the scale notation "1:100"?

  1. The pipe sizes are all 100 mm nominal
  2. The drawing was printed at 100 sheets per set
  3. The building is 100 meters tall
  4. One unit measured on the drawing represents 100 of the same units on the actual building Correct answer.

Explanation

A drawing scale states the ratio between a measured length on the paper and the corresponding real length. At 1:100, a 10 mm line on the sheet represents 1000 mm on site, so the plumber must scale dimensions accordingly.

Question 24Interpretation of technical drawings, plans, and specifications

A plumbing legend on the drawing shows a solid line labeled "CW" and a dashed line labeled "HW". How should the plumber interpret these symbols?

  1. Solid line is gas and dashed line is vent
  2. Both lines represent drain pipes of different diameters
  3. Solid line is hot water and dashed line is cold water
  4. Solid line is cold water supply and dashed line is hot water supply Correct answer.

Explanation

The legend defines the meaning of each line type on that drawing set, and the abbreviations CW and HW stand for cold water and hot water. Line style alone is meaningless without the legend, so the plumber always reads the legend first.

Question 25Interpretation of technical drawings, plans, and specifications

Which drawing type would a plumber consult to see the vertical arrangement of stacks, branches, and vent connections through the floors of a building?

  1. Site plan
  2. Riser diagram Correct answer.
  3. Detail section
  4. Floor plan

Explanation

A riser diagram is a schematic elevation showing how stacks, branches, traps, and vents connect vertically and how fixtures relate to each other. It is the primary drawing for understanding the vertical piping system.

Question 26Interpretation of technical drawings, plans, and specifications

A specification clause states that all soil pipes shall conform to a listed national standard. What is the plumber's obligation when reading this clause?

  1. Use pipe materials and fittings that comply with the referenced standard Correct answer.
  2. Use the cheapest pipe on the market
  3. Ignore the clause if the drawing does not repeat it
  4. Choose any pipe available in the warehouse

Explanation

Specifications are part of the contract documents and a referenced standard makes compliance mandatory. The plumber must supply and install materials that meet that standard, and the standard number should be checked against the delivered materials.

Question 27Interpretation of technical drawings, plans, and specifications

On a plumbing plan, a fixture is shown as a circle with a cross inside and a dimension leader reading "Ø 100". What does this symbol most likely indicate?

  1. A floor drain with a 100 mm diameter connection Correct answer.
  2. A vent terminal on the roof
  3. A pressure gauge on a water line
  4. A water closet with a 100 mm seat

Explanation

A circle with a cross is the conventional symbol for a floor drain, and the leader with Ø 100 gives the nominal diameter of its outlet connection. The plumber uses this to select the correct drain body and pipe size.

Question 28Interpretation of technical drawings, plans, and specifications

A section drawing shows a water closet with the finished floor line and a dimension of 300 mm from the finished floor to the centerline of the soil pipe stub-out. Why is this dimension important?

  1. It sets the rough-in height so the fixture outlet aligns with the stub-out Correct answer.
  2. It specifies the water pressure at the fixture
  3. It determines the color of the fixture
  4. It indicates the drain slope of the branch

Explanation

A rough-in dimension from the finished floor to the pipe centerline tells the plumber where to leave the stub-out so the fixture outlet connects without modification. If the stub-out is set at the wrong height, the fixture cannot be installed at the correct level.

Question 29Interpretation of technical drawings, plans, and specifications

A drawing shows a pipe labeled "DN 50 PVC". How should the plumber interpret this callout?

  1. Nominal diameter 50 mm, material polyvinyl chloride Correct answer.
  2. Slope 1 in 50, material PVC
  3. Length 50 mm, material copper
  4. Pressure rating 50 bar, material PVC

Explanation

DN stands for nominal diameter and the number gives the size in millimeters, while PVC names the material. Together the callout tells the plumber which pipe size and material to order for that run.

Question 30Interpretation of technical drawings, plans, and specifications

A plan note reads "VTR - 100 mm Ø, terminate 600 mm above roof". What does VTR stand for and what does the note require?

  1. Vent through roof; the vent pipe must extend 600 mm above the roof surface Correct answer.
  2. Vertical tank riser; the tank must be 600 mm tall
  3. Vent trap receiver; the trap must be 600 mm deep
  4. Valve trim riser; the valve must be 600 mm from the wall

Explanation

VTR is the standard abbreviation for vent through roof, and the note gives both the pipe diameter and the height above the roof. The plumber must install the vent so it terminates at that height to discharge gases safely above the roof.

Question 31Interpretation of technical drawings, plans, and specifications

A plumbing drawing shows a horizontal branch with an arrow and the note "fall 1:40 to stack". What should the installer do?

  1. Lay the branch level so water stands in the pipe
  2. Lay the branch so it falls toward the stack at 1 unit per 40 units of run Correct answer.
  3. Lay the branch so it rises toward the stack
  4. Install the branch at 40 degrees to horizontal

Explanation

The arrow shows the direction of flow and the ratio gives the gradient, so the pipe must fall toward the stack at 1 in 40. This keeps waste moving and prevents solids from settling in the branch.

Question 32Interpretation of technical drawings, plans, and specifications

A detail drawing shows a pipe passing through a concrete floor slab with a sleeve and a sealant callout. What is the purpose of reading this detail before construction?

  1. To know the sleeve size, position, and sealing method required at the penetration Correct answer.
  2. To select the fixture trim
  3. To calculate the water demand of the building
  4. To determine the paint color of the pipe

Explanation

A penetration detail specifies the sleeve diameter, its position relative to the slab, and how the annular gap is sealed. Reading it before construction lets the plumber set the sleeve during concreting rather than cutting later.

Question 33Interpretation of technical drawings, plans, and specifications

A drawing carries the abbreviation "F.F.L." next to a vertical dimension. What does this abbreviation mean?

  1. Floor flange location
  2. Full flow line
  3. Finished floor level Correct answer.
  4. Fixture fixing line

Explanation

F.F.L. stands for finished floor level, the datum from which many plumbing rough-in heights are measured. Using the correct datum prevents errors when setting fixture and pipe heights.

Question 34Interpretation of technical drawings, plans, and specifications

A plumbing plan is drawn at 1:50, but the printed sheet has been photocopied and reduced to 80 percent. How should the plumber handle dimensions taken from this copy?

  1. Divide all scaled measurements by 0.8 and proceed
  2. Multiply all scaled measurements by 0.8 and proceed
  3. Use the written dimensions on the drawing and do not scale from the reduced copy Correct answer.
  4. Assume the scale is now 1:100 and proceed

Explanation

When a drawing is reproduced at a different size, the printed scale no longer matches the sheet, so scaled measurements become unreliable. Written dimensions govern, and the plumber should request the original or a controlled print for any missing dimension.

Question 35Interpretation of technical drawings, plans, and specifications

A plumbing schedule lists a water closet with a "rough-in of 300 mm" and a "trapway of 100 mm". Which two pieces of information does this give the plumber?

  1. The weight of the fixture and the color
  2. The flush volume and the water pressure
  3. The height of the seat and the width of the bowl
  4. The distance from the finished wall to the drain center and the outlet size of the fixture Correct answer.

Explanation

In a fixture schedule, rough-in is the distance from the finished wall to the drain centerline, and trapway is the diameter of the fixture outlet. Both values are needed to set out the drain and select the correct pipe size.

Question 36Interpretation of technical drawings, plans, and specifications

A plumbing plan shows a soil stack passing through a bathroom with a branch to a water closet and a separate branch to a lavatory. The lavatory branch is drawn with a smaller diameter than the water closet branch. Why is this arrangement shown?

  1. The lavatory branch carries hot water only
  2. Fixture outlet sizes differ, so each branch must match the fixture it serves Correct answer.
  3. The lavatory branch is a vent, not a drain
  4. Smaller branches are always drawn to save ink

Explanation

Each branch is sized to the fixture outlet it serves, so a water closet with a larger trapway needs a larger branch than a lavatory. The drawing reflects the required pipe sizing, and the plumber must follow the indicated diameters.

Question 37Interpretation of technical drawings, plans, and specifications

A drawing shows a vent stack offset around a structural beam using two 45-degree bends. Why must the plumber read this detail carefully before fabrication?

  1. The offset geometry and bend angles determine the cut lengths and fitting layout Correct answer.
  2. The bends increase the water pressure in the stack
  3. The bends change the vent pipe material
  4. The offset eliminates the need for a vent

Explanation

An offset detail gives the bend angles and the horizontal and vertical distances, which together fix the cut lengths of pipe between fittings. Fabricating without reading the detail risks a misaligned offset that will not connect.

Question 38Interpretation of technical drawings, plans, and specifications

A drawing set shows a floor plan with a soil pipe at 1:100 and a matching detail at 1:20. The same pipe appears as a 3 mm line on the plan and a 15 mm line on the detail. What explains this difference?

  1. The pipe size changes between the two drawings
  2. The detail is drawn at a larger scale, so the same pipe is represented by a wider line Correct answer.
  3. The plan is wrong and should be discarded
  4. The detail uses a different pipe material

Explanation

At 1:20 the drawing is five times larger than at 1:100, so the same physical pipe is drawn five times wider on the detail. The apparent line width reflects scale, not a change in pipe size or material.

Question 39Interpretation of technical drawings, plans, and specifications

A specification requires that drainage pipes below ground be laid on a prepared bed and that all joints be tested before backfilling. A drawing note shows only the pipe alignment. How should the plumber proceed?

  1. Backfill first and test later to save time
  2. Follow only the specification and ignore the alignment
  3. Follow only the drawing because it is the most recent document
  4. Follow both the drawing for alignment and the specification for bedding and testing Correct answer.

Explanation

Drawings and specifications are complementary contract documents, and the plumber must satisfy both. The drawing locates the pipe, while the specification governs bedding, jointing, and testing before backfill.

Question 40Interpretation of technical drawings, plans, and specifications

A plumbing plan shows a vent pipe crossing a supply pipe in plan view. How does the plumber determine which pipe is in front at that crossing?

  1. Measure the line thickness on the plan
  2. Assume the vent is always in front
  3. Check the section or elevation drawing to see the vertical relationship Correct answer.
  4. Assume the supply is always in front

Explanation

A plan view shows only horizontal positions, so a crossing gives no vertical information by itself. The plumber must consult a section, elevation, or riser to see which pipe passes above or below the other.

Question 41Measurement, layout, and marking out of plumbing works

A plumber needs a horizontal drain line to fall 1:50 over a run of 6 meters. What is the total fall in millimeters?

  1. 300 mm
  2. 12 mm
  3. 60 mm
  4. 120 mm Correct answer.

Explanation

A 1:50 gradient means 1 unit of fall for every 50 units of horizontal run. Converting 6 m to 6000 mm and dividing by 50 gives 120 mm of total fall.

Question 42Measurement, layout, and marking out of plumbing works

On a metric steel tape, the smallest numbered graduation on the main scale usually represents which length?

  1. 1 decimeter
  2. 1 millimeter
  3. 1 meter
  4. 1 centimeter Correct answer.

Explanation

Metric tapes number every centimeter and subdivide each numbered interval into ten millimeters with the smallest lines. The numbered marks therefore indicate centimeters, while the fine lines are millimeters.

Question 43Measurement, layout, and marking out of plumbing works

When marking a vertical soil pipe position on a wall, which tool gives the most reliable true-vertical reference?

  1. A spirit level with a plumb vial Correct answer.
  2. A steel square held against the floor
  3. A folding wooden rule
  4. A chalk line snapped by eye

Explanation

A spirit level's plumb vial is designed to indicate true vertical, so it is the correct reference for aligning a riser. A chalk line or square held by eye introduces error because neither references gravity directly.

Question 44Measurement, layout, and marking out of plumbing works

A pipe centerline must be set 350 mm from a finished wall. The pipe outside diameter is 60 mm. What distance should be marked from the wall to the near face of the pipe?

  1. 320 mm Correct answer.
  2. 350 mm
  3. 290 mm
  4. 380 mm

Explanation

The centerline is 350 mm from the wall, so the near face lies closer to the wall by half the outside diameter, which is 30 mm. Subtracting gives 320 mm from the wall to the pipe face.

Question 45Measurement, layout, and marking out of plumbing works

A level vial reads correctly only when its bubble sits between the two reference lines. What does this indicate?

  1. The vial needs recalibration regardless of bubble position
  2. The instrument is magnetized
  3. The vial axis is horizontal within the sensitivity of the vial Correct answer.
  4. The vial is filled with the wrong fluid

Explanation

The bubble rises to the highest point of the curved vial, so centering it between the lines means the vial axis is horizontal within the vial's sensitivity. This is the normal reading condition, not a fault.

Question 46Measurement, layout, and marking out of plumbing works

A drainage run of 8 m must achieve a fall of 160 mm. What gradient does this represent, expressed as a ratio of 1 in x?

  1. 1 in 50 Correct answer.
  2. 1 in 20
  3. 1 in 16
  4. 1 in 80

Explanation

The gradient ratio equals run divided by fall, so 8000 mm divided by 160 mm gives 50. The fall is therefore 1 in 50.

Question 47Measurement, layout, and marking out of plumbing works

When transferring a level line around a room to set fixture heights, which practice keeps the marks consistent?

  1. Estimating heights by eye at each fixture
  2. Using one reference datum and measuring up from it at each location Correct answer.
  3. Measuring down from the ceiling at each wall separately
  4. Using a different datum on each wall for convenience

Explanation

All heights should be referenced to a single datum so that fixtures align across the room. Measuring from different references on each wall accumulates error and misaligns the installation.

Question 48Measurement, layout, and marking out of plumbing works

A 90-degree bend is to be laid out on a pipe using a steel square. Which measurement must be equal on both legs to confirm a true right angle?

  1. The wall thickness at each cut
  2. The thread lengths on each end
  3. The distances measured along each leg from the corner Correct answer.
  4. The pipe diameters at each end

Explanation

A right angle is verified by equal measured distances along both legs plus a check of the diagonal. Pipe diameter, wall thickness, and thread length do not define the angle.

Question 49Measurement, layout, and marking out of plumbing works

A plumber marks a 45-degree offset on a pipe. Which method correctly establishes the 45-degree line around the pipe?

  1. Marking a line parallel to the pipe seam
  2. Using a tape to measure the circumference only
  3. Drawing a line straight along the pipe with a rule
  4. Wrapping a flexible strip around the pipe so the ends meet squarely and marking along the edge Correct answer.

Explanation

A flexible strip wrapped so its ends align produces a true circumferential line, and a mark along its edge gives the required angle. Lines drawn freehand along the pipe do not guarantee the correct angle.

Question 50Measurement, layout, and marking out of plumbing works

A cast iron soil pipe is to be cut and a new branch set out. Which layout step should be done before cutting to avoid cumulative error?

  1. Set the branch position from the cut end only
  2. Cut the pipe first and fit the branch by trial
  3. Establish and mark the centerline of the branch from a fixed datum Correct answer.
  4. Mark the branch by eye after assembly

Explanation

Branch positions should be set from a fixed datum so errors do not accumulate along the run. Working from a cut end or by trial transfers error into the installation.