Mixed Deck — All Plumbing Topics Flashcards

Which fitting should be used when connecting a horizontal drain line to another horizontal drain line at the same elevation?

Answer: 45-degree wye

A 45-degree wye fitting is used to connect horizontal drain branches because it promotes laminar flow and reduces the chance of blockages.

What is the safe, approved method for detecting a gas leak at a fitting or connection?

Answer: Apply soapy water and watch for bubbles

Applying an approved leak detection solution or soapy water to fittings and observing for bubbles is the safe standard method — open flames are extremely dangerous.

What does the term 'authority having jurisdiction' (AHJ) mean in plumbing codes?

Answer: The local government body or official responsible for enforcing building and plumbing codes

The AHJ is the local organization, office, or individual responsible for enforcing the requirements of the applicable plumbing code in that jurisdiction.

What is required before starting a major plumbing project in most US jurisdictions?

Answer: A plumbing permit from the local authority having jurisdiction (AHJ)

Most major plumbing work requires a permit from the local authority having jurisdiction (AHJ), ensuring the work is inspected and meets code requirements.

What is the minimum water pressure required at a residential fixture per the IPC?

Answer: 20 psi

The IPC requires a minimum static water pressure of 20 psi at every plumbing fixture to ensure adequate flow for proper operation.

What is the maximum distance a lavatory trap can be from its vent?

Answer: 4 feet

Under the IPC, a lavatory (sink) with a 1.25-inch pipe has a maximum trap-to-vent distance of 3.5 feet, but the common code limit for lavatories is 5 feet depending on jurisdiction — 4 feet is the most commonly tested standard answer.

What is a backflow preventer and when is it required on a residential irrigation system?

Answer: A device preventing contaminated water from flowing back into the potable supply; required on all irrigation connections

A backflow preventer stops potentially contaminated irrigation water (containing fertilizers, pesticides) from flowing back into the potable water supply, and is required on all residential irrigation connections.

What is the purpose of a pipe reamer or deburring tool after cutting pipe?

Answer: To remove the interior burr left by cutting to restore full flow area

A reamer removes the interior burr created by a pipe cutter, restoring the full bore diameter and preventing the burr from causing turbulence or catching debris.

What type of fitting connects two pipes of different materials, such as copper to CPVC?

Answer: Transition fitting

A transition fitting is specifically designed to connect pipes made of different materials, ensuring a watertight seal between dissimilar pipe types.

What type of wax ring alternative provides a better seal for uneven floors when installing a toilet?

Answer: Double-stacked wax ring or foam gasket seal

For uneven floors or extra-thick flooring, a double-stacked wax ring or a foam gasket seal (like Fluidmaster) provides a better, adjustable seal than a single wax ring.

What is 'potable water' and why is it important in plumbing codes?

Answer: Water that is safe for human consumption and meets EPA standards

Potable water is water that is safe for human consumption, cooking, and personal hygiene, and plumbing codes contain extensive provisions to protect it from contamination.

What is the maximum typical low-pressure natural gas system operating pressure for residential appliances?

Answer: 0.5 psi (14 in. WC)

Residential natural gas appliances typically operate at low pressure — commonly 7 in. WC for most appliances, with a maximum of about 14 in. WC (0.5 psi) at the appliance.

What type of valve is used as the main shutoff valve for a residential water supply?

Answer: Ball valve or gate valve

Ball valves or gate valves are used as main shutoff valves because they provide full-bore flow when open and a complete shutoff when closed.

What is the function of a fill valve in a toilet tank?

Answer: To refill the tank with water after flushing

The fill valve (ballcock) automatically refills the toilet tank with fresh water after each flush and shuts off when the water reaches the correct level.

What fitting is typically installed at each gas appliance to allow individual shutoff without interrupting the entire system?

Answer: Appliance shutoff valve (gas cock)

An appliance shutoff valve (gas cock or stop valve) is required at each appliance connection to allow safe individual isolation for service or emergencies.

What is the purpose of a tempering valve (mixing valve) on a water heater?

Answer: To blend hot and cold water to deliver water at a safe temperature

A tempering valve blends hot and cold water to deliver water at a pre-set safe temperature (typically 120°F) to prevent scalding.

What does 'wet venting' mean in a plumbing system?

Answer: A single pipe that serves as both a drain and a vent

Wet venting uses a single oversized pipe that serves simultaneously as a drain for one fixture and a vent for another downstream fixture.

What is the correct rough-in height for a bathroom lavatory (sink) drain?

Answer: 16–20 inches AFF

Standard lavatory drain rough-in height is 16 to 20 inches above the finished floor (AFF), with 18 to 20 inches being most common for standard-height vanities.

What is the minimum water seal depth required in a standard P-trap?

Answer: 2 inches

The IPC requires a minimum water seal depth of 2 inches in a P-trap to prevent sewer gases from entering the building.

Which pipe material is best suited for underground sewer lines due to its chemical resistance?

Answer: Schedule 40 PVC

Schedule 40 PVC is widely used for underground sewer lines because of its excellent chemical resistance and durability in soil environments.