Grade 10 building construction – Plumbing Materials Quiz
1. Which material is commonly used for underground sewer and drainage pipes in modern Kenyan buildings?
uPVC is durable, inexpensive, resistant to corrosion and chemicals, and easy to install, so it is widely used for underground sewer and drainage pipes.
2. Which pipe material is suitable for carrying hot domestic water without deforming?
CPVC is formulated to withstand higher temperatures than standard PVC and is commonly used for hot water distribution in buildings.
3. What is the common method used to join uPVC plumbing pipes?
uPVC pipes are normally joined by solvent welding, which chemically fuses the pipe and fitting using primer and cement to form a leak-proof joint.
4. What is the main advantage of galvanized iron (GI) pipes over plain steel pipes?
Galvanized iron pipes have a zinc coating that protects the steel from rusting, making them more durable for water supply than plain uncoated steel.
5. Which material should not be used for drinking water supply because it can cause poisoning?
Lead pipes or leaded solder can release lead into drinking water, causing serious health problems, so they must not be used for potable water supply.
6. Which type of plastic pipe is commonly used for flexible cold-water underground mains and irrigation in Kenya?
HDPE is flexible, strong, resistant to chemicals and abrasion, and commonly used for cold-water mains and irrigation pipelines.
7. Which plumbing fitting is used to join two pipes of different diameters?
A reducer is a fitting used to connect pipes of different diameters, reducing flow from a larger pipe to a smaller one.
8. Which valve type is best when you need to quickly open or close the flow of water?
Ball valves provide quick quarter-turn operation and reliable shut-off, making them ideal where fast opening or closing is required.
9. What is the purpose of a plumbing trap (e.g., P-trap) under a sink?
A trap retains a small amount of water that acts as a seal against sewer gases, preventing them from coming back into rooms.
10. In plumbing, pipe sizes are commonly referred to by which term?
Nominal bore (NB) is the standard way to refer to pipe sizes in plumbing and gives an approximate internal diameter used for selecting fittings and flow capacity.
11. Which material is best for carrying aggressive chemical waste from laboratories because of high chemical resistance?
HDPE has excellent chemical resistance and is often used where pipes must carry corrosive or aggressive chemical wastes.
12. What is the usual method for joining copper water pipes in household plumbing?
Copper pipes are commonly joined by soldering or brazing; for potable water systems, lead-free solders are used to avoid contamination.
13. Which fitting is used to change the direction of a pipe run by 90 degrees?
An elbow fitting is made to change the direction of a pipe, commonly available in 90-degree and 45-degree angles.
14. Which material is often used for large external water mains because of its strength and ability to handle high pressure?
Ductile iron pipes are strong, can withstand high pressures, and are commonly used for large external water mains in municipal and rural supply systems.
15. Which plastic pipe should not be used for carrying hot water because it softens at higher temperatures?
Standard PVC is intended for cold water and drainage; it can deform or soften at high temperatures and is therefore unsuitable for hot water supply.
16. Which device prevents water from flowing backwards into the supply line, protecting the clean water from contamination?
A check valve allows flow in one direction only and prevents backflow, protecting the potable supply from contamination.
17. Which pipe material will rust if left unprotected outdoors?
Unprotected mild steel corrodes (rusts) when exposed to moisture and air; coatings or galvanizing are needed to prevent rust.
18. What is the common sealant used on threaded plumbing joints to prevent leaks?
PTFE tape is wrapped around pipe threads to fill gaps and help form a watertight seal on threaded joints.
19. What material are most sanitary fixtures (toilets and washbasins) made from?
Toilets and washbasins are usually made from vitreous china, a glazed ceramic that is smooth, durable, easy to clean and water-resistant.
20. Which pipe type is lightweight, easy to cut and glue, and commonly used for cold water supply and downpipes?
uPVC is lightweight, simple to work with using cutting and solvent-jointing, and is commonly used for cold water lines and rainwater downpipes.
21. Which material is commonly used for domestic gas supply pipework for LPG or natural gas in buildings?
Black steel (mild steel) pipes are commonly used for gas installations because they are strong and suitable for threaded connections used in gas work.
22. Which material is often used for rainwater downpipes on houses because it resists weathering and is low cost?
uPVC downpipes are common because they resist corrosion, are lightweight, inexpensive and easy to install for roof drainage.
23. What is a flange used for in plumbing systems?
A flange provides a bolted connection between pipe ends or between a pipe and equipment, allowing strong, removable joints.
24. Which of the following is a key property of copper pipes that makes them suitable for plumbing?
Copper has excellent thermal conductivity and good resistance to corrosion, which makes it suitable for hot and cold water systems.
25. Why are flexible braided hoses used to connect taps and appliances to water supply pipes?
Flexible hoses are used because they are easy to install, can accommodate slight misalignment, and absorb vibration and movement between rigid pipework and fixtures.
26. Which plumbing material is most commonly used in Kenya for underground cold water supply lines because it is lightweight, corrosion-resistant and easy to join with solvent cement?
PVC is widely used for underground cold water supply as it is light, resists corrosion, inexpensive and joined easily with solvent cement, making it common in Kenyan plumbing.
27. Which material is preferred for domestic hot water pipes because it tolerates higher temperatures and is easy to joint by soldering or brazing?
Copper tolerates high temperatures, resists corrosion, and can be soldered or brazed, making it suitable for domestic hot water systems.
28. Which pipe material should be avoided for carrying drinking water because it can release toxic substances and is now banned for potable water supply in many countries?
Lead can leach into water and cause health problems; it is no longer used for potable water systems and is avoided in modern plumbing.
29. Which type of pipe is commonly used for soil and waste drainage inside buildings because of its smooth surface and resistance to sewage chemicals?
PVC drainage pipes (often uPVC) have a smooth inner surface, resist chemical attack from sewage, and are commonly used for soil and waste lines inside buildings.
30. Which plumbing material expands more than others when exposed to hot water and therefore requires allowance for thermal expansion in installation?
Plastic pipes like PEX expand more with temperature changes than metals, so installers must allow for thermal expansion when fitting them.
31. Which valve type is best suited for fully stopping or allowing flow in a water supply line but is not ideal for regulating flow?
Gate valves are designed for on/off service and provide little control for flow regulation; globe valves are better for regulating flow.
32. Which jointing method is commonly used to connect PVC pipes together in Kenyan plumbing installations?
Solvent welding uses a primer and cement to chemically fuse PVC pipes and fittings, which is the standard joining method for PVC plumbing.
33. Which material is often used for heavy-duty underground sewer pipelines in buildings and for stormwater drains due to its strength and durability?
Reinforced concrete pipes are strong and durable, making them suitable for large buried sewer and stormwater drains that carry heavy loads.
34. Which type of fitting is used to prevent foul air from the sewer entering a building while allowing waste water to flow out?
P-traps (U-traps) hold a water seal that stops sewer gases from entering the building while permitting wastewater to pass into drainage.
35. Which material is commonly used nowadays for water supply inside houses as a cheaper, corrosion-resistant alternative to copper and is installed with heat fusion or push-fit joints?
Plastic systems like PEX or PPR are cost-effective, resist corrosion, and are joined by heat fusion or push-fit connectors, becoming common in modern installations.
36. Which fitting is used to change the direction of a pipe run by 90 degrees in a drainage or water supply system?
An elbow fitting changes the direction of piping, commonly available in 90° and 45° forms used in water supply and drainage systems.
37. Which pipe material is most resistant to rust and is commonly used for exposed external taps and fittings that must resist weathering?
Stainless steel resists rust and corrosion even when exposed to weather, making it a good choice for external fittings and taps.
38. Which material is best for kitchen and bathroom sink waste pipes because it combines durability with ease of fitting and cleaning?
uPVC waste fittings are durable, easy to install and maintain, and are commonly used for sink wastes in kitchens and bathrooms.
39. Which type of sealant or tape is commonly used on threaded plumbing joints to prevent leaks?
PTFE tape is wrapped on male threads to provide a good seal and help prevent leaks on threaded plumbing joints.
40. Which pipe material is heavy, long-lasting and was traditionally used for vertical soil stacks but is being replaced by plastics due to weight and cost?
Cast iron has been used for soil stacks because of its durability and sound-deadening properties, but plastic alternatives are lighter and cheaper.
41. Which property is most important when selecting a pipe material for carrying hot water in a residential building?
Pipes carrying hot water must resist high temperatures without deforming or degrading, so thermal resistance is the key property to consider.
42. Which plumbing component prevents reverse flow of water and is important to protect a clean water supply from contamination?
A non-return (check) valve allows flow in one direction only and prevents backflow that could contaminate the potable water supply.
43. Which material is commonly used for water meters and fittings where mechanical strength and resistance to pressure are needed at the point of supply?
Brass and bronze are strong, corrosion-resistant metals commonly used for meters, taps and fittings at water supply points.
44. Which type of pipe joint is typically used with copper piping and requires heating to melt filler metal into the joint?
Copper pipes are commonly joined by soldering or brazing, where heat melts a filler metal to create a watertight joint.
45. Which plastic pipe type is preferred for both hot and cold water distribution in many modern Kenyan homes because it handles high temperatures and pressure better than ordinary PVC?
CPVC is designed to withstand higher temperatures and pressures than standard PVC, making it suitable for hot and cold water distribution.
46. Which plumbing material should be selected for rainwater downpipes from roofs for cost-effectiveness and resistance to rust?
uPVC downpipes are inexpensive, do not rust and are easy to install, making them a common choice for roof rainwater drainage.
47. Which component is fitted to sinks and basins to trap debris and prevent it from entering the drainage system while allowing water to flow?
A basket strainer sits in the sink waste to catch debris and prevent blockages, while letting water pass down the drain.
48. Which material is known for good acoustic damping in soil and waste pipes inside buildings, reducing noise from water flow?
Cast iron has high mass and dampening properties, so it reduces flow noise in soil and waste pipes compared with light plastics.
49. Which type of fitting is used to connect pipes of different diameters in a plumbing system?
A reducer fitting connects pipes of different diameters, allowing a larger pipe to transition to a smaller one.
50. Which property of plumbing materials is most critical when choosing pipes for an area with highly acidic or alkaline water to avoid rapid deterioration?
Water with high acidity or alkalinity can corrode pipes; selecting materials with good chemical resistance prevents rapid deterioration and leaks.
51. Which pipe material is commonly used in Kenya for cold potable water supply inside buildings?
uPVC is widely used for cold potable water because it is durable, lightweight, corrosion-resistant and easy to join with solvent cement.
52. Which pipe material is commonly used for hot water plumbing because it tolerates high temperatures well?
Copper conducts heat well and resists high temperatures, making it a common choice for hot water supply pipes.
53. Which material is most commonly used for soil and waste (drainage) pipes inside buildings?
uPVC is commonly used for soil and waste pipes because it is lightweight, corrosion-resistant and easy to join and install for drainage systems.
54. Which of these materials is least likely to corrode (rust) when used for plumbing?
Stainless steel contains chromium which forms a protective film, making it highly resistant to rust and corrosion compared with ordinary steels.
55. Which plumbing material is typically joined by soldering?
Copper pipes are normally joined by soldering (soft or hard solder) to create leak-proof metallic joints.
56. Which joining method is commonly used to connect uPVC pipes and fittings?
uPVC pipes are commonly joined with solvent cement which chemically softens and fuses the pipe and fitting surfaces together.
57. Which plastic pipe is flexible and commonly used for underground cold water mains in Kenya?
HDPE is flexible, tough and resistant to corrosion and chemicals, making it suitable for buried cold water mains.
58. Which material should not be used for drinking water pipes because it causes health hazards?
Lead can leach into drinking water and cause serious health problems; it is therefore no longer used for potable water pipes.
59. What material is commonly used for large diameter street water mains and is known for strength and durability?
Ductile iron pipes are strong and durable, commonly used for large diameter mains and high-pressure water distribution.
60. In pipe colour coding, which colour is normally used to identify cold water pipes?
Blue is commonly used to mark cold water services, while red is used for hot water; colour coding helps quick identification during maintenance.
61. Which advantage is associated with PEX (cross-linked polyethylene) pipes in domestic plumbing?
PEX is flexible, allowing long runs with fewer joints and fittings, which reduces leak points and speeds installation.
62. Which pipe material gives better noise reduction for drainage because of its mass?
Cast iron is heavy and dense, which helps reduce noise from flowing water and waste compared with lighter plastic pipes.
63. Which plumbing material is commonly connected using BSP (British Standard Pipe) threads?
Galvanized steel fittings and pipes are often manufactured with BSP threads for screwed connections in plumbing.
64. Which material is joined by solvent welding (chemical welding)?
Solvent welding dissolves the surface of uPVC and fuses parts together, which is the normal method to join uPVC pipes and fittings.
65. What does the pipe size term 'nominal bore (NB)' usually refer to?
Nominal bore is a conventional designation indicating the approximate inside diameter used to identify and select pipe sizes.
66. Which material shows very good chemical resistance and is often used where aggressive chemicals might be present?
HDPE resists many chemicals and is therefore used in situations where chemical attack could damage other pipe materials.
67. Which plumbing material is commonly used for house gas piping (domestic LPG) installations inside buildings?
Black steel pipe is commonly used for gas piping because it is strong and suitable for threaded metal gas fittings; plastics like uPVC are not suitable for gas.
68. Which plumbing component is made from pipe material and used to keep foul smells from the sewer out of the building?
A trap is a bent pipe section that holds water to form a seal preventing sewer gases from entering a building.
69. Which material used in hot water cylinders is often protected by a sacrificial anode?
Steel hot water tanks are prone to corrosion, so a sacrificial anode (usually magnesium or aluminium) is fitted to corrode instead and protect the tank.
70. Which pipe material is light in weight, making it easy for students to carry and learn about in class practicals?
uPVC is lightweight compared with metal pipes, so it is easier to handle in practical lessons and on-site work by students.
71. Which plastic pipe type is suitable for both pressure and non-pressure underground water supply?
HDPE is used for both pressured water mains and non-pressure installations underground because of its strength, flexibility and jointing methods.
72. Which fitting is used to change the direction of a pipe by 45 degrees?
A 45-degree elbow bends the pipe by 45 degrees and is used to alter direction with less flow resistance than a 90-degree elbow.
73. Which sealing material is normally wrapped around threaded pipe joints to prevent leaks?
PTFE tape is commonly wrapped on male threads before screwing joints together to improve the seal and prevent leaks.
74. Which common plumbing material is recyclable and widely used for stormwater and drainage pipes?
PVC/uPVC is widely used for drainage and stormwater pipes and can be recycled, reducing waste from construction work.