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.