Plastic Pipes Basic

Question 1

Q: What is PVC used for?

Answer 1

Cold water and drainage systems.

Question 2

What is CPVC used for?

Answer 2

Hot and cold water supply.

Question 3

What is ABS used for?

Answer 3

Drainage, venting, and underground applications.

Question 4

Why shouldn’t you use PVC for hot water?

Answer 4

It can melt or fail under high temperatures.

Question 5

Do you need primer for ABS pipes?

Answer 5

No — only solvent cement is needed.

Question 6

What happens if you skip the primer on PVC or CPVC?

Answer 6

Weak joints and potential leaks.

Question 7

How long should you hold the pipe in place after applying cement?

Answer 7

10–30 seconds.

Question 8

How long should solvent cement cure before pressure testing?

Answer 8

At least 24 hours (depending on temperature and cement type).

Question 9

What’s the danger of using PVC for compressed air systems?

Answer 9

It can shatter and cause serious injury.

Question 10

What causes cracks from thermal expansion?

Answer 10

Not allowing room for pipe expansion or contraction.

Question 11

What does a plumber review before designing a plumbing system?

Answer 11

Blueprints and schematics.

Question 12

Set 2: Overview Of New Construction Plumbing

Question 13

What must plumbers consider when sizing water and drain pipes?

Answer 13

Number of fixtures and building water pressure.

Question 14

What happens during the “rough-in” stage?

Answer 14

Install water lines, drainage, venting, and sewer lines before drywall is installed.

Question 15

Why are shut-off valves important?

Answer 15

They allow isolated repairs without affecting the whole system.

Question 16

What types of plumbing fixtures might a plumber install?

Answer 16

Toilets, sinks, faucets, showers, bathtubs, dishwashers, water heaters.

Question 17

Dishwasher Install - New Construction Plumbing Flashcards

Question 18

What size hot water line is typically used for a new construction dishwasher install?

Answer 18

1/2” PEX or copper hot water line.

Question 19

Where should the hot water line terminate in a rough-in?

Answer 19

In the sink base cabinet with 3-4” of pipe stubbed out, capped or with a shut-off valve.

Question 20

What size drain line is used for a dishwasher rough-in?

Answer 20

1.5” or 2” PVC or ABS pipe.

Question 21

Where is the dishwasher drain line connected?

Answer 21

To a wye fitting or branch tailpiece under the kitchen sink.

Question 22

What electrical is required for a dishwasher?

Answer 22

A dedicated 15-amp circuit with 3-wire Romex (black, white, ground).

Question 23

How is the power provided for a dishwasher?

Answer 23

Either coiled Romex for hardwire or an outlet for plug-in.

Question 24

What fitting is used to connect a dishwasher supply line to the unit?

Answer 24

A 90° elbow fitting (3/8” compression to 3/4” dishwasher thread).

Question 25

What should you use on threaded fittings to prevent leaks?

Answer 25

Teflon tape or pipe thread compound.

Question 26

How should the dishwasher drain hose be routed?

Answer 26

In a high loop under the sink or to an air gap (if required by code).

Question 27

Where does the drain hose connect under the sink?

Answer 27

To the garbage disposal or the sink drain tailpiece.

Question 28

How is a hardwired dishwasher connected electrically?

Answer 28

Black to black, white to white, and ground to ground screw in the unit.

Question 29

What do you check during the dishwasher test cycle?

Answer 29

Leaks at the supply line, drain hose, and under the unit.

Question 30

: What must you do to ensure proper dishwasher operation after install?

Answer 30

Ensure the unit is level and securely installed.

Question 31

Why is a high loop or air gap important in the drain hose?

Answer 31

To prevent dirty water from siphoning back into the dishwasher.

Question 32

What local requirement might override a high loop setup?

Answer 32

Some codes require an air gap instead of a high loop.

Question 33

Water Supply Line Flashcard

Question 34

What size pipe is typically used for the main water line from a meter or well?

Answer 34

¾" to 1"

Question 35

What size pipe is used for branch lines supplying multiple fixtures?

Answer 35

¾"

Question 36

What size pipe is used for individual fixture supply lines like sinks or toilets?

Answer 36

½"

Question 37

What are the most common materials used for water supply lines?

Answer 37

PEX, copper, or CPVC

Question 38

Why is PEX often preferred over copper?

Answer 38

It’s flexible and easier to install.

Question 39

Drain, Waste & Vent (DWV) Flashcards

Question 40

What size pipe is used for the main sewer line to the city or septic?

Answer 40

4"

Question 41

What size pipe is typically used for toilet drains and main drain stacks?

Answer 41

3"

Question 42

What size pipe is used for showers, washing machines, and kitchen sinks?

Answer 42

2"

Question 43

What size pipe is used for bathroom sinks and dishwashers?

Answer 43

1½"

Question 44

What slope is required for proper drainage of DWV pipes?

Answer 44

¼” per foot

Question 45

What’s the purpose of vent pipes in plumbing?

Answer 45

To remove sewer gases and allow proper airflow in drain systems.

Question 46

🔥 Gas Line Flashcards

Question 47

What size gas line supplies the entire house?

Answer 47

¾" to 1"

Question 48

What size gas line is used for appliances like a stove or water heater?

Answer 48

½"

Question 49

What materials are used for gas lines?

Answer 49

Black iron, CSST, or copper (if allowed)

Question 50

🌬️ Vent Pipe Sizing Flashcards

Question 51

What size vent pipe is used for bathroom sinks and dishwashers?

Answer 51

1½"

Question 52

What size vent is used for showers, bathtubs, and washing machines?

Answer 52

2"

Question 53

What size is the main vent stack in most homes?

Answer 53

3" or 4"

Question 54

What type of vent system is used when no vertical vent is possible (e.g., kitchen islands)?

Answer 54

Loop vent

Question 55

What’s an Air Admittance Valve (AAV)?

Answer 55

A mechanical vent that opens to allow air in when water drains.

Question 56

Are Air Admittance Valves legal everywhere?

Answer 56

No, check local codes.

Question 57

⚠️ Venting Rules Flashcards

Question 58

What’s the required slope for vent pipes?

Answer 58

¼” per foot

Question 59

How high must a vent be above the flood level of a fixture?

Answer 59

At least 6" above the overflow level

Question 60

How far can a toilet be from its vent?

Answer 60

No more than 6 feet

Question 61

Can vent pipes be run horizontally under a slab?

Answer 61

No, they must rise vertically first.