Question 1

Studies indicate that the drainage fixture unit for a fixture is influenced by the type of building in which the fixture is installed.

Accepted Answer

The drainage fixture unit (DFU) for a fixture is determined by various factors including the type of building, the size of the fixture, and its intended use. Therefore, the DFU can be influenced by the type of building in which the fixture is installed.

Question 2

What is the minimum diameter pipe that could serve as a stack with six branch intervals and 300 DFUs?&#10;A) 3 inches&#10;B) 4 inches&#10;C) 5 inches&#10;D) 6 inches

Accepted Answer

According to the International Plumbing Code (IPC), the DFU is a measure of the amount of water entering a drainage system, and the value for a horizontal branch interval is 1 DFU per linear foot. Therefore, for six branch intervals, a total of 6 DFUs per linear foot will be produced. The minimum pipe diameter required to serve this amount of DFUs according to the IPC is 4 inches. Therefore, the correct answer is B.

Question 3

What is the DFU value for a bathroom group having a 1.6 gpf gravity tank water closet in a single dwelling?&#10;A) 3&#10;B) 4&#10;C) 5&#10;D) 6

Accepted Answer

According to the Uniform Plumbing Code, a 1.6 gpf gravity tank water closet has a DFU value of 3. In a bathroom group containing a water closet, a lavatory, and a bathtub or shower with a total fixture count of 3, the total DFU value would be 5 (3 for the water closet and 1 each for the lavatory and bathtub/shower). Therefore, the best choice is C.

Question 4

An individual drain line must never be smaller than the trap to which it connects.

Accepted Answer

This is because a smaller drain line would cause an obstruction and prevent proper drainage, leading to potential backup and clogging in the plumbing system.

Question 5

A horizontal branch with 3 water closets (1.6 gpf gravity tank) and two lavatories (1 1/4&#34; waste) can be served with a ____ inch pipe.&#10;A) 3&#10;B) 4&#10;C) 6&#10;D) 2

Accepted Answer

According to the plumbing code, each water closet requires a 3-inch waste pipe and each lavatory requires a 1 1/4-inch waste pipe. Therefore, the total pipe size needed is 3 inches (for the 3 water closets) plus 2 x 1 1/4 inches (for the two lavatories), which equals 5 1/2 inches. The code requires that the pipe size be rounded up to the nearest even number, which in this case is 6 inches. Therefore, the best choice is C, but since it is not an option, the next best choice is B which is also an even number and larger than the calculated 5 1/2 inch pipe size.

Question 6

What is the minimum diameter pipe that can be installed as a building drain (slope 1/8&#34;/ ft) when the DFU load is 460 DFU?&#10;A) 6 inches&#10;B) 4 inches&#10;C) 5 inches&#10;D) 8 inches

Accepted Answer

According to plumbing codes, a 6-inch diameter pipe is required for a building drain with a slope of 1/8" per foot to handle a load of 460 Drainage Fixture Units (DFU).

Question 7

What is the minimum diameter pipe that could serve as a stack with two branch intervals and 250 DFUs?&#10;A) 5 inches&#10;B) 3 inches&#10;C) 6 inches&#10;D) 4 inches

Accepted Answer

The minimum diameter pipe that could serve as a stack with two branch intervals and 250 DFUs is 5 inches. This is because the minimum diameter pipe that can serve 250 DFUs is 4 inches, and each branch interval adds 1 inch to the diameter.

Question 8

If the offset angle in a stack is less than 45 degrees, the offset is sized as a&#10;A) vertical line.&#10;B) horizontal line.&#10;C) building drain.&#10;D) fixture drain.

Accepted Answer

When the offset angle in a stack is less than 45 degrees, it is considered a building drain and should be sized accordingly. Therefore, the best choice is C.

Question 9

One bathroom group serving an individual dwelling is equal to 5 DFUs.

Accepted Answer

This is true according to the International Plumbing Code. DFU stands for Drainage Fixture Unit, which is a standardized unit used to measure the flow capacity of plumbing fixtures and drainage pipes. A bathroom group including a toilet, sink, and shower or bathtub is typically assigned a value of 5 DFUs in residential plumbing design.

Question 10

Most codes require the minimum drain size below a slab to be&#10;A) 1inches&#10;B) 1inches&#10;C) 2 inches&#10;D) 2inches

Accepted Answer

Most codes require a minimum drain size of 2 inches below a slab to ensure proper drainage and prevent clogging. A larger drain size can also help prevent potential backups and blockages in the future.

Question 11

In a single-family residence, a 1.6 gpf gravity tank water closet has a DFU value of&#10;A) 2.0&#10;B) 2.5&#10;C) 3.0&#10;D) 3.5

Accepted Answer

The answer of In a single-family residence, a 1.6 gpf...

Question 12

The drainage fixture unit value is used to&#10;A) determine the probable maximum load on a drainage system.&#10;B) determine the sizing of the fixtures.&#10;C) determine the number of fixtures a building can accommodate.&#10;D) determine the number of bathrooms a building can have.

Accepted Answer

The answer of The drainage fixture unit value is used...

Question 13

Which of the following affects individual fixture drain sizing?&#10;A) diameter of the waste outlet&#10;B) trap size&#10;C) desired velocity of waste material in the drain&#10;D) all of the above

Accepted Answer

The answer of Which of the following affects individual fixture...

Question 14

Drainage fixture unit values are different for 3.5 gpf and 1.6 gpf water closets.

Accepted Answer

The answer of Drainage fixture unit values are different for...

Question 15

When selecting the drain pipe size, you want one with the highest velocity of flow.

Accepted Answer

The answer of When selecting the drain pipe size, you...

Deck 11: Drainage Fixture Units