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Maharashtra SSC Plumber (General) Pre-Voc/NSQF study materials
Maharashtra SSC Plumber (General) Pre-Voc/NSQF study resources

Maharashtra SSC Plumber (General) Pre-Voc/NSQF practice questions

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Question 1Occupational Safety, Health and Working Environment

While threading a galvanized iron pipe with a manual die stock, a plumber must protect his eyes. Which personal protective equipment is most appropriate for this task?

  1. A dust respirator with clear visor
  2. Ordinary prescription spectacles
  3. Safety goggles with side shields Correct answer.
  4. A face shield worn over a cloth cap

Explanation

Threading and cutting metal produces flying chips and fine metal particles that can enter the eye from the side as well as the front. Safety goggles with side shields seal around the eye and are the standard eye protection for pipe threading and cutting work. Spectacles alone leave gaps, and a respirator does not protect the eyes.

Question 2Occupational Safety, Health and Working Environment

A plumber must enter a septic tank chamber to clear a blocked outlet. Which precaution is essential before entry?

  1. Opening the cover and waiting five minutes for the smell to fade
  2. Wearing a cotton mask and carrying a torch
  3. Testing the atmosphere for oxygen and toxic gases and arranging a standby observer Correct answer.
  4. Entering quickly to reduce the time spent inside

Explanation

Septic tanks and confined spaces can contain hydrogen sulphide, methane, and low oxygen, which can kill within seconds. The safe procedure is to test the atmosphere with a calibrated gas detector, ventilate, and keep a trained standby person outside with rescue arrangements. Smell is not a reliable indicator because high concentrations deaden the sense of smell.

Question 3Occupational Safety, Health and Working Environment

On a construction site, a plumber needs to work at a height of 3 metres on a scaffold to fix a rainwater downpipe. Which practice meets basic fall-protection requirements?

  1. Working from a fully planked platform with guardrails and a harness where required Correct answer.
  2. Balancing on a stack of bricks beside the wall
  3. Standing on the top guardrail to reach the pipe
  4. Using a ladder placed on the scaffold platform

Explanation

Fall protection at height requires a stable, fully planked working platform with guardrails and toe boards, and a full-body harness anchored correctly where the risk assessment requires it. Improvised standing surfaces such as rails, bricks, or ladders on platforms are common causes of fatal falls.

Question 4Occupational Safety, Health and Working Environment

A plumber is about to solder copper joints with a blowlamp inside a small bathroom with the door closed. What is the main safety concern and the correct control?

  1. Slip risk; lay a mat on the floor
  2. Electric shock; switch off the lighting circuit
  3. Fume and fire risk; ventilate the area and keep a fire extinguisher nearby Correct answer.
  4. Noise; wear ear plugs

Explanation

Soldering produces fumes from flux and can ignite nearby combustible material, especially in a small enclosed room. The correct control is to ventilate the space, remove or shield combustibles, and keep suitable fire-fighting equipment at hand. Noise, electric shock, and slipping are not the primary hazards of a blowlamp.

Question 5Occupational Safety, Health and Working Environment

Which action best prevents musculoskeletal injury when lifting a heavy cast-iron soil pipe with a helper?

  1. Bending the back and twisting while lifting
  2. Lifting the pipe alone to save time
  3. Keeping the load close to the body and lifting with the legs while coordinating with the helper Correct answer.
  4. Holding the breath and jerking the pipe upward

Explanation

Safe manual handling keeps the load close to the trunk, uses the leg muscles rather than the back, and avoids twisting. When two people lift, they must agree on signals and lift together to share the load evenly. Jerking or twisting sharply is a frequent cause of back strain.

Question 6Occupational Safety, Health and Working Environment

Before using a portable electric drill on a wet floor near a water tank, which precaution gives the best protection against electric shock?

  1. Using an RCD-protected supply and inspecting the cable and plug Correct answer.
  2. Wearing rubber sandals
  3. Working quickly to finish before the floor gets wetter
  4. Holding the drill with both hands

Explanation

The main defence against electric shock from portable tools in wet conditions is a residual current device that trips on earth leakage, together with inspection of the tool, cable, and plug for damage. Footwear alone cannot be relied on, and speed does not reduce the hazard.

Question 7Occupational Safety, Health and Working Environment

A plumber must cut a pipe with a hacksaw in a workshop where another worker is grinding nearby. What is the most effective way to reduce the combined noise hazard?

  1. Shout to communicate over the noise
  2. Work faster to finish sooner
  3. Wear ear plugs rated for the noise level and limit exposure time Correct answer.
  4. Turn the radio up to mask the grinding

Explanation

Hearing damage from workshop noise depends on both the sound level and the duration of exposure. Correctly rated hearing protection combined with reduced exposure time gives effective protection, and noise levels should be monitored. Masking noise with a radio or shouting does not reduce the energy reaching the ear.

Question 8Occupational Safety, Health and Working Environment

A worker spills solvent-based pipe cement on his forearm. What is the correct immediate first-aid response according to the safety data sheet?

  1. Wash the skin thoroughly with plenty of water and remove contaminated clothing Correct answer.
  2. Wait for a blister to form before taking action
  3. Rub the area with a dry cloth and continue working
  4. Apply an oily cream and cover the area

Explanation

The safety data sheet for solvent-based cement directs that contaminated skin be washed with plenty of water and affected clothing removed to stop continued absorption and irritation. Rubbing or covering the area can spread the chemical or trap it against the skin. Medical advice should be sought if irritation persists.

Question 9Occupational Safety, Health and Working Environment

Which storage practice is correct for solvent-based pipe cement and primer on a site?

  1. Keeping them in a locked, ventilated store away from ignition sources Correct answer.
  2. Storing them in a sealed plastic bag under a tarpaulin
  3. Placing them beside the drinking-water container
  4. Storing them in an open tray near a welding area

Explanation

Pipe cement and primer are flammable and give off vapours, so they must be kept in a locked, well-ventilated store away from flames, sparks, and hot work. Containers should be closed when not in use. Storing them near ignition sources or drinking water creates fire and contamination risks.

Question 10Occupational Safety, Health and Working Environment

A plumber is working in a trench 1.5 metres deep to repair a drainage line. The sides are loose soil. What is the correct safety action?

  1. Shore or batter the sides and provide a safe means of access and escape Correct answer.
  2. Work only at the ends of the trench
  3. Enter without support but keep a rope tied to the waist
  4. Ask a colleague to watch from the top only

Explanation

Loose soil in a trench can collapse suddenly and bury a worker, so the sides must be shored, benched, or battered back to a safe angle, with a ladder for access and escape. A watcher alone cannot prevent or rescue from a collapse. Working at the ends does not remove the risk.

Question 11Occupational Safety, Health and Working Environment

What is the primary purpose of a permit-to-work system for hot work such as brazing on site?

  1. To formally confirm that fire precautions and isolations are in place before work starts Correct answer.
  2. To replace the need for a fire extinguisher
  3. To calculate the cost of the job
  4. To record the worker's attendance

Explanation

A permit-to-work is a formal written control that confirms hazards have been assessed and precautions such as fire watch, removal of combustibles, and isolation of services are in place before hot work begins. It does not replace physical precautions such as extinguishers.

Question 12Occupational Safety, Health and Working Environment

A plumber finds an old pipe that may contain asbestos insulation while renovating a building. What is the correct action?

  1. Wet it and continue with a normal hacksaw
  2. Cover it with tape and complete the job
  3. Break it off quickly and bag the pieces
  4. Stop work, isolate the area, and report it for assessment by a competent person Correct answer.

Explanation

Asbestos fibres released by cutting or breaking old insulation can cause serious lung disease, so work must stop immediately, the area must be isolated, and the material must be assessed by a competent person before any disturbance. Only trained and authorised people with proper controls may handle asbestos.

Question 13Occupational Safety, Health and Working Environment

Which of these is the best way to control the risk of slipping on a wet bathroom floor during a plumbing installation?

  1. Placing warning signs and mopping up spills promptly Correct answer.
  2. Asking workers to walk slowly
  3. Ignoring the water until the job is finished
  4. Wearing ordinary canvas shoes

Explanation

Slips on wet floors are controlled by removing the hazard, for example by mopping up spills and using drainage or drip trays, and by warning people where wet areas remain. Slow walking and ordinary shoes do not remove the water, and ignoring it allows the hazard to persist.

Question 14Occupational Safety, Health and Working Environment

A plumber must use a ladder to reach a ceiling-level pipe connection. Which practice is correct?

  1. Overreaching sideways while both feet stay on the rung
  2. Leaning the ladder at a safe angle, securing it, and keeping three points of contact Correct answer.
  3. Using a wooden ladder with a split stile
  4. Standing on the top two rungs to gain extra height

Explanation

Ladders must be set on firm ground at a safe angle, secured against slipping, and used so that the worker keeps three points of contact and avoids overreaching. Standing on the top rungs or using damaged equipment greatly increases the risk of a fall.

Question 15Occupational Safety, Health and Working Environment

A plumber is asked to work inside a newly coated water tank where the coating is still curing. Which control is most important before entry?

  1. Forced ventilation and atmosphere testing for solvent vapour and oxygen Correct answer.
  2. Wearing a high-visibility vest
  3. Carrying a mobile phone
  4. Entering with a colleague who has no training

Explanation

Freshly applied coatings release solvent vapour that can displace oxygen and create a flammable or toxic atmosphere inside a tank. Forced ventilation and atmosphere testing before and during entry are essential, along with a standby person and rescue arrangements. A high-visibility vest or phone does not control the atmospheric hazard.

Question 16Occupational Safety, Health and Working Environment

Which of the following describes the correct use of a fire extinguisher on a small electrical fire in a pump control panel?

  1. Isolate the power if safe, then use a CO2 extinguisher Correct answer.
  2. Smother the panel with a wet cloth
  3. Use a water extinguisher directly on the panel
  4. Use a foam extinguisher on the live panel

Explanation

For an electrical fire, the power should be isolated if it is safe to do so, and a carbon dioxide extinguisher is suitable because it leaves no residue and is non-conductive. Water and foam conduct electricity and can cause shock or spread the fire, and a wet cloth is not a safe extinguishing method.

Question 17Occupational Safety, Health and Working Environment

A plumber notices that the guard on a bench grinder used for sharpening tools is missing. What is the correct action?

  1. Ask a trainee to hold a board as a shield
  2. Wear gloves and use the grinder anyway
  3. Use the grinder carefully without the guard
  4. Report the defect and do not use the machine until it is repaired Correct answer.

Explanation

Machine guards are a legal requirement and protect against contact with rotating parts and flying fragments. A missing guard makes the machine unsafe, so it must be taken out of use, tagged, and reported for repair. Gloves near rotating machinery can also be caught and pulled in.

Question 18Occupational Safety, Health and Working Environment

Which is the correct way to dispose of used solvent-soaked rags after a plumbing job?

  1. Burn them on site
  2. Leave them in a corner to dry out
  3. Place them in a closed metal container and dispose as hazardous waste Correct answer.
  4. Throw them in the general waste bin

Explanation

Solvent-soaked rags can self-heat and ignite, and they are hazardous waste, so they must be kept in a closed metal container and disposed of through the proper hazardous-waste route. Leaving them lying about or burning them creates fire and pollution risks.

Question 19Occupational Safety, Health and Working Environment

What is the main purpose of a toolbox talk before starting a plumbing task on site?

  1. To check the quality of the finished pipework
  2. To order new materials
  3. To brief the team on the specific hazards, controls, and emergency arrangements for the task Correct answer.
  4. To assign wages for the day

Explanation

A toolbox talk is a short briefing that communicates the hazards of the day's task, the controls to be used, and what to do in an emergency. It ensures every worker understands the risks before work begins. It is not a payroll, quality-inspection, or purchasing activity.

Question 20Occupational Safety, Health and Working Environment

A plumber is working alone in a remote plant room when he starts to feel dizzy and short of breath after using a solvent. Which response is most appropriate?

  1. Drink water and keep working until the shift ends
  2. Continue the job but open a small window
  3. Stop work, move to fresh air, and seek help or call emergency services Correct answer.
  4. Lie down inside the plant room to rest

Explanation

Dizziness and breathlessness after solvent exposure may indicate inhalation of vapour or oxygen deficiency, so the worker must stop, get to fresh air, and summon help. Remaining in the area or resting inside can lead to collapse and loss of consciousness. Lone working in such areas should be controlled by a risk assessment.

Question 21Hand Tools, Power Tools and Measuring Instruments

Which hand tool is used to cut internal threads in a pipe fitting?

  1. Tap Correct answer.
  2. Pipe wrench
  3. Die
  4. Flaring tool

Explanation

A tap is a hardened steel tool with external cutting threads that is rotated into a drilled hole to cut internal (female) threads. A die performs the opposite job, cutting external threads on a pipe end or rod. Pipe wrenches and flaring tools do not cut threads at all.

Question 22Hand Tools, Power Tools and Measuring Instruments

On a standard steel measuring tape, the smallest graduation normally marked on the metric edge is:

  1. 10 mm
  2. 5 mm
  3. 1 mm Correct answer.
  4. 0.5 mm

Explanation

Standard metric tape blades are graduated in millimetres, with the smallest division being 1 mm; every tenth millimetre is usually numbered in centimetres. The 5 mm and 10 mm marks are longer reference lines within that scale, not the finest graduation.

Question 23Hand Tools, Power Tools and Measuring Instruments

Before using an electric pipe-threading machine, the first safety action is to:

  1. Check that the machine is earthed and the switch is off Correct answer.
  2. Set the pipe on the rear support arm
  3. Loosen the chuck jaws fully
  4. Apply cutting oil to the die head

Explanation

Earthing (grounding) and confirming the switch is in the off position protect the operator from electric shock before any power tool is energised. Oil, pipe support and chuck adjustment are set-up steps that follow once the machine is confirmed safe.

Question 24Hand Tools, Power Tools and Measuring Instruments

A plumber needs to hold a pipe firmly for filing without crushing it. Which tool is most suitable?

  1. Stillson wrench
  2. Bolt cutter
  3. Bench hook
  4. Chain pipe vice Correct answer.

Explanation

A chain pipe vice grips the pipe around its circumference with a chain, spreading the clamping load so the pipe is held securely without being crushed. A bench hook is a woodworking aid, a wrench is for turning fittings, and a bolt cutter is a cutting tool.

Question 25Hand Tools, Power Tools and Measuring Instruments

The main purpose of a pipe cutter's reamer is to:

  1. Remove the internal burr left by the cutting wheel Correct answer.
  2. Widen the pipe end for a socket
  3. Measure the pipe diameter
  4. Square the cut end of the pipe

Explanation

Cutting with a wheel leaves a sharp internal burr that reduces bore and disturbs flow, so the reamer blade is inserted and rotated to shave this burr away. Squaring the end is done by the cutting wheel itself, and widening or measuring are unrelated functions.

Question 26Hand Tools, Power Tools and Measuring Instruments

Which instrument gives the most accurate direct reading of a pipe's outside diameter?

  1. Vernier calliper Correct answer.
  2. Try square
  3. Steel rule
  4. Spirit level

Explanation

A vernier calliper measures across the outside of a pipe with jaws and reads to 0.02 mm or finer on its vernier scale, giving the most accurate diameter. A steel rule reads only to about 1 mm and must be aligned by eye, while a try square and spirit level measure squareness and level.

Question 27Hand Tools, Power Tools and Measuring Instruments

A hacksaw blade marked 24 TPI is best suited for:

  1. Cutting cast iron soil pipe
  2. Cutting a large-diameter steel bar
  3. Cutting plastic conduit only
  4. Cutting thin-walled copper tube Correct answer.

Explanation

TPI means teeth per inch; 24 TPI gives fine teeth that cut thin sections smoothly without snagging. Coarse blades of about 14 to 18 TPI suit thick sections such as cast iron or heavy bar, and plastic conduit is normally cut with a fine-toothed saw or shear.

Question 28Hand Tools, Power Tools and Measuring Instruments

While threading a galvanised pipe by hand with a die stock, the plumber should apply cutting oil and:

  1. Run the die dry to avoid slipping
  2. Hammer the die onto the pipe
  3. Reverse the die a quarter turn after every full turn forward Correct answer.
  4. Turn the die continuously in one direction

Explanation

Backing off a quarter turn after each forward turn breaks the chip and prevents it from packing into the die, giving clean threads and reducing the risk of tearing. Continuous turning jams the chips, hammering damages the die, and running dry causes overheating and poor threads.

Question 29Hand Tools, Power Tools and Measuring Instruments

A plumber reads 12.5 cm on a steel rule but needs the value in millimetres. The correct conversion is:

  1. 1250 mm
  2. 12.5 mm
  3. 1.25 mm
  4. 125 mm Correct answer.

Explanation

One centimetre equals ten millimetres, so 12.5 cm is multiplied by 10 to give 125 mm. Dividing by 10 gives 1.25 mm and multiplying by 100 gives 1250 mm, both of which are incorrect conversions.

Question 30Hand Tools, Power Tools and Measuring Instruments

When using a spirit level to check that a horizontal pipe run falls at the correct gradient, the plumber should:

  1. Rely on the bubble position in the cross vial only
  2. Place the level across the pipe diameter
  3. Hold the level vertically against the pipe end
  4. Lay the level along the pipe and check the bubble between the lines Correct answer.

Explanation

The main longitudinal vial of a spirit level is set parallel to the base, so laying the level along the pipe run shows whether the fall is uniform and correct. The cross vial, vertical use and placing across the diameter check level across the pipe or plumb, not the gradient along the run.

Question 31Hand Tools, Power Tools and Measuring Instruments

The main reason for using a pipe wrench with jaws set at right angles to the handle is to:

  1. Increase the length of the handle
  2. Reduce the weight of the tool
  3. Allow the wrench to be used in tight spaces and improve grip direction Correct answer.
  4. Allow the wrench to cut threads

Explanation

An offset or angled jaw head lets the wrench grip a fitting close to a wall or in a recess and directs the turning force correctly on the pipe. Handle length, weight and thread cutting are fixed properties unrelated to jaw orientation.

Question 32Hand Tools, Power Tools and Measuring Instruments

A plumber must cut a 15 mm copper tube square for a compression fitting. The most suitable hand tool for a clean, square cut is:

  1. Roller-type tube cutter Correct answer.
  2. Junior hacksaw with a fine blade
  3. Wood saw
  4. Cold chisel

Explanation

A roller-type tube cutter scores and rolls the copper around its circumference, producing a square end that seats correctly in a compression fitting. A hacksaw can cut copper but tends to leave a slanted end needing filing, and a chisel or wood saw is unsuitable for tube.

Question 33Hand Tools, Power Tools and Measuring Instruments

A pipe vice is bolted to the bench with its jaws closed and the pipe is clamped. The main advantage of this set-up over holding the pipe by hand is:

  1. It allows both hands free to operate the die stock safely Correct answer.
  2. It measures the pipe length
  3. It makes the pipe lighter to handle
  4. It automatically cuts threads

Explanation

Clamping the pipe in a vice holds it rigid so the plumber can use both hands to guide and turn the die stock, giving control and reducing injury risk. The vice does not change the pipe's weight, cut threads or measure length.

Question 34Hand Tools, Power Tools and Measuring Instruments

A plumber is choosing between a 300 mm and a 450 mm pipe wrench for a tight joint on a 50 mm pipe. The longer wrench is preferred because it:

  1. Cuts threads while turning
  2. Has finer jaw teeth for plastic fittings
  3. Weighs less and is easier to carry
  4. Provides greater leverage and turning force for the same hand effort Correct answer.

Explanation

Torque equals force multiplied by the distance from the pivot, so a longer handle gives more turning force for the same hand effort, which helps free a tight joint. The longer wrench is heavier, its teeth are not finer, and it cannot cut threads.

Question 35Hand Tools, Power Tools and Measuring Instruments

A plumber needs to check that a newly installed vertical soil pipe is perfectly upright. The correct instrument and method is:

  1. Steel tape run along the pipe length
  2. Spirit level held vertically against the pipe, reading the vertical vial Correct answer.
  3. Try square laid across the pipe mouth
  4. Vernier calliper at the pipe joint

Explanation

A spirit level used vertically reads plumb through its vertical vial, showing whether the pipe is truly upright. A tape measures length, a calliper measures diameter, and a try square checks squareness of an end face rather than verticality of the run.

Question 36Hand Tools, Power Tools and Measuring Instruments

A plumber must remove a rounded, damaged nut from a valve body. Which hand tool gives the best grip without cutting into the valve?

  1. Adjustable wrench with smooth jaws Correct answer.
  2. Cold chisel
  3. Stillson pipe wrench
  4. Bolt cutter

Explanation

An adjustable wrench with smooth jaws grips the flats of a hex nut and turns it without cutting into the metal, which suits a valve body that must not be damaged. A pipe wrench has hardened teeth that bite and mark fittings, and a bolt cutter or chisel would destroy the nut.

Question 37Hand Tools, Power Tools and Measuring Instruments

A plumber uses a vernier calliper with a main scale reading of 24 mm and a vernier scale that reads 0.36 mm. The measured outside diameter of the pipe is:

  1. 2.436 mm
  2. 24.036 mm
  3. 243.6 mm
  4. 24.36 mm Correct answer.

Explanation

The vernier calliper reading is the main scale value plus the vernier scale value, so 24 mm plus 0.36 mm equals 24.36 mm. The other options misplace the decimal point by factors of ten or more.

Question 38Hand Tools, Power Tools and Measuring Instruments

During hand threading of a 25 mm steel pipe, the plumber notices the thread is ragged and the die is hard to turn. The most likely cause is:

  1. The die stock handle is too short
  2. The cutting oil is too thin
  3. The die is misaligned on the pipe end and the pipe is not chamfered Correct answer.
  4. The pipe is too cold to cut

Explanation

A die that is not started square on the pipe cuts a tapered, ragged thread and binds, and an unchamfered pipe end makes starting square even harder. Handle length, pipe temperature and oil viscosity do not by themselves produce a ragged, binding thread.

Question 39Hand Tools, Power Tools and Measuring Instruments

A plumber must cut a 100 mm cast iron soil pipe on site with hand tools. The most appropriate choice is:

  1. A coarse-toothed hacksaw or a cast iron cutter with a fine blade and steady pressure Correct answer.
  2. A wood saw with hardened teeth
  3. A 32 TPI hacksaw blade used with heavy pressure
  4. A tube cutter with a roller wheel

Explanation

Cast iron is hard and brittle, so a coarse blade of about 14 to 18 TPI, or a dedicated cast iron cutter, clears the swarf and cuts steadily without snatching. A very fine 32 TPI blade clogs and overheats, a wood saw is unsuitable, and a roller tube cutter is meant for soft copper.

Question 40Hand Tools, Power Tools and Measuring Instruments

A plumber checks a horizontal drain run with a 600 mm spirit level and finds the bubble centred. The run is 6 m long and must fall 1 in 60. The plumber should:

  1. Introduce the required fall by packing or adjusting supports, since a centred bubble means no fall over that length Correct answer.
  2. Replace the level with a try square
  3. Accept the run because the bubble is centred
  4. Shorten the level to check again

Explanation

A centred bubble on a level laid along the pipe means that section is horizontal, so no gradient exists and the required fall of 1 in 60 must be built in by adjusting supports or packing. Accepting the run would leave the drain flat and prone to blockage, and changing the tool does not create a fall.

Question 41Materials, Pipes, Fittings and Jointing Methods

In a Maharashtra SSC Plumber workshop, a trainee needs a pipe for buried cold-water service where cost is the main concern. Which pipe material is most commonly specified for this purpose?

  1. Unplasticised PVC (uPVC) pipe Correct answer.
  2. Copper pipe
  3. Cast iron soil pipe
  4. Galvanised mild steel pipe

Explanation

Buried cold-water distribution lines in Indian practice are most often laid in uPVC because it is cheap, corrosion-free and easy to joint with solvent cement. Galvanised steel and copper cost far more and are reserved for exposed or hot-water work, while cast iron is a drainage material.

Question 42Materials, Pipes, Fittings and Jointing Methods

A plumber must cut an internal thread on a 25 mm galvanised steel pipe. Which tool is the correct choice for this operation?

  1. Pipe cutter with a cutting wheel
  2. Hacksaw with a fine-tooth blade
  3. Ratchet die stock with a pipe die Correct answer.
  4. Flaring tool

Explanation

Threads on GI pipe are cut with a pipe die held in a ratchet die stock, working progressively with cutting oil. A pipe cutter or hacksaw only severs the pipe, and a flaring tool is used on copper tubing for flare joints.

Question 43Materials, Pipes, Fittings and Jointing Methods

While jointing uPVC pipes with solvent cement, the trainee applies cement and pushes the pipe fully into the socket. What is the purpose of the short twist given during insertion?

  1. To remove excess cement from the outside of the socket
  2. To cool the joint so the cement sets faster
  3. To enlarge the socket so the pipe enters more easily
  4. To spread the cement evenly and break any trapped air film Correct answer.

Explanation

A quarter-turn during insertion spreads the solvent cement over the full socket depth and squeezes out air pockets that would otherwise weaken the weld. The joint is then held under pressure for a few seconds until it grips.

Question 44Materials, Pipes, Fittings and Jointing Methods

Which fitting is used to connect two pipes of different diameters in a straight run?

  1. Bend
  2. Reducer Correct answer.
  3. Equal tee
  4. Union

Explanation

A reducer is the fitting that changes pipe size within a straight line of pipework. A tee branches at 90 degrees, a bend changes direction, and a union joins two same-size pipes so they can be dismantled.

Question 45Materials, Pipes, Fittings and Jointing Methods

A plumber is joining 15 mm copper tube for an exposed hot-water line in a bathroom. Which jointing method gives a permanent, neat joint without a separate fitting body?

  1. Capillary soldered joint Correct answer.
  2. Threaded joint with hemp
  3. Compression fitting
  4. Push-fit fitting

Explanation

Capillary soldering uses the tube ends themselves with a small solder-ring fitting and produces a slim, permanent joint once the tube and fitting are cleaned and fluxed. Compression and push-fit joints rely on rubber seals and are bulkier, while copper tube is not normally threaded.

Question 46Materials, Pipes, Fittings and Jointing Methods

Which property of GI pipe makes it suitable for drinking-water supply lines?

  1. The pipe is a good electrical insulator
  2. The steel is softer than copper so it bends easily
  3. The pipe is transparent so flow can be seen
  4. The zinc coating resists corrosion of the steel beneath Correct answer.

Explanation

Galvanising deposits a zinc layer that protects the steel from rust in water service, which is why GI pipe is accepted for potable lines. The zinc is sacrificial, so cut ends and threads should be painted or doped to restore protection.

Question 47Materials, Pipes, Fittings and Jointing Methods

A drainage line must change direction from vertical to horizontal at the foot of a stack. Which fitting is appropriate?

  1. Sanitary tee
  2. Coupling
  3. 45 degree bend
  4. Shoe (heel) bend Correct answer.

Explanation

A shoe or heel bend has a gentle sweep at the base of a stack that guides flow smoothly into the horizontal drain without splash or blockage. A sanitary tee is for branch connections and a coupling only joins straight lengths.

Question 48Materials, Pipes, Fittings and Jointing Methods

What is the standard purpose of a plumber's pipe vice when cutting threads on a pipe?

  1. To measure the length of thread required
  2. To apply cutting oil to the die
  3. To ream the inside burr after cutting
  4. To hold the pipe firmly without crushing it while the die is turned Correct answer.

Explanation

A pipe vice grips the pipe between shaped jaws so it cannot rotate while the die stock is turned, and the jaws are designed to hold round sections without collapsing them. Measuring, reaming and oiling are separate operations with separate tools.

Question 49Materials, Pipes, Fittings and Jointing Methods

Which of these is the correct sequence for making a threaded GI pipe joint with hemp and white lead (or jointing compound)?

  1. Wind dry hemp anticlockwise, then paint the joint
  2. Apply hemp to the female thread only, then tighten the fitting
  3. Apply compound to the male thread, wind hemp clockwise, then screw the fitting on Correct answer.
  4. Screw the fitting on dry, then force hemp into the gap

Explanation

Jointing compound is smeared on the male thread, hemp is wound in the direction of the thread so it tightens rather than unwinds, and the fitting is then screwed on. The fibres swell against water and the compound seals the gaps.

Question 50Materials, Pipes, Fittings and Jointing Methods

A plumber needs to join two lengths of 110 mm PVC soil pipe where the joint may need to be opened later for rodding. Which joint type is best suited?

  1. Rubber ring push-fit joint Correct answer.
  2. Welded joint
  3. Lead-caulked joint
  4. Solvent-cemented joint

Explanation

Push-fit joints with a rubber sealing ring allow the pipe to be pushed together and later pulled apart for maintenance, which is valuable on drainage runs. Solvent cement and welding are permanent, and lead caulking belongs to cast iron work.