C-36 Plumbing – Practice Exam 1

Welcome to your C-36 Plumbing - Practice Exam 1

What is the purpose of 'pipe insulation' on cold water supply pipes in areas where freezing is possible?

What is the purpose of 'pipe insulation' on cold water supply pipes in areas where freezing is possible?Deselect Answer

Insulation is only required on hot water pipes

Insulation protects cold water pipes from freezing in unheated spaces (attics, crawl spaces, garages, exterior walls) — frozen water expands with tremendous force (approximately 30,000 PSI) and can split copper, crack plastic, or burst fittings. Pipe insulation also prevents condensation on cold water pipes in humid conditions

Cold water pipe insulation is only for noise reduction

Pipe insulation on cold water pipes reduces water pressure

None

What is the purpose of 'dielectric unions' when connecting copper pipe to steel or galvanized steel fittings?

What is the purpose of 'dielectric unions' when connecting copper pipe to steel or galvanized steel fittings?Deselect Answer

They provide a watertight connection between two pipes of the same material

They isolate the two dissimilar metals (copper and steel) with a plastic or rubber insulator — preventing galvanic corrosion caused by the electrochemical reaction between dissimilar metals in the presence of water. Without dielectric isolation, the less noble metal (typically steel) corrodes rapidly at the contact point

Dielectric unions are used only for gas piping connections

They provide expansion joints between copper and steel piping

None

What is the purpose of 'rough-in dimensions' for plumbing fixtures?

What is the purpose of 'rough-in dimensions' for plumbing fixtures?Deselect Answer

The measurements of the finished fixture itself

The specific distances from the finished wall, floor, or reference point to the centerline(s) of the supply and waste connections — determined before walls and floors are finished. These dimensions ensure the fixture will fit properly with proper supply and drain alignments when finish work is complete

The dimensions used for ordering pipe quantities

The measurements for permit application only

None

What is the purpose of an 'air admittance valve' (AAV) in plumbing?

What is the purpose of an 'air admittance valve' (AAV) in plumbing?Deselect Answer

A valve that allows air into the water supply to prevent vacuum

A one-way mechanical vent device that opens under negative pressure to admit air into the drain system, preventing trap siphoning — it closes under positive pressure, preventing sewer gas from escaping. AAVs eliminate the need to run vent piping to the roof when used under specific California Plumbing Code conditions

An air release valve for pressurized water supply lines

A check valve preventing air from entering drain lines

None

What is 'thermal expansion' in a closed plumbing system and how is it addressed?

What is 'thermal expansion' in a closed plumbing system and how is it addressed?Deselect Answer

The expansion of pipe diameter when heated water flows through it

When water is heated in a water heater in a closed system (with a backflow preventer or check valve on the supply), the expanding water has no place to go — pressure rises to potentially dangerous levels. An expansion tank sized for the system volume is required by California Plumbing Code to absorb the expanding water safely

Thermal expansion only affects copper pipe — plastic pipe is exempt

Thermal expansion is prevented by installing a larger water heater

None

What is the purpose of a 'hot water recirculation system' and what plumbing components does it require?

What is the purpose of a 'hot water recirculation system' and what plumbing components does it require?Deselect Answer

A hot water recirculation system increases cold water pressure

A hot water recirculation system continuously or intermittently circulates hot water through the distribution piping to keep hot water at each fixture at all times — eliminating the wait for hot water at distant fixtures. Required components: a dedicated return line from the farthest fixture back to the water heater, a small circulation pump, a check valve preventing reverse flow, a crossover valve (or dedicated return connection) at fixtures, and a control system (timer or thermostat or push-button demand activation)

Recirculation systems require a second water heater

Hot water recirculation is only used in commercial buildings

None

What is a 'janitor's service sink' (mop sink) and what are its special requirements?

What is a 'janitor's service sink' (mop sink) and what are its special requirements?Deselect Answer

A standard laundry tub used for general cleaning

A deep-basin, floor-mounted or wall-mounted sink designed for filling and emptying mop buckets and rinsing cleaning equipment. Special requirements: (1) hot and cold water supply; (2) a hose connection with a vacuum breaker (backflow prevention); (3) typically 3-inch drain; (4) must not share a trap with a floor drain; (5) often requires a protective rim guard to prevent mop handles from contacting finished walls

A janitor's service sink is only required in commercial buildings over 10,000 sq ft

Mop sinks use the same rough-in as kitchen sinks

None

What minimum pipe size is required for a building drain serving a residential building with a 3/4 bathroom (toilet, lavatory, tub)?

What minimum pipe size is required for a building drain serving a residential building with a 3/4 bathroom (toilet, lavatory, tub)?Deselect Answer

2-inch pipe

3-inch pipe

4-inch pipe

6-inch pipe

None

What is a 'stack vent' in a plumbing system?

What is a 'stack vent' in a plumbing system?Deselect Answer

A separate vent pipe parallel to the soil stack

The extension of the soil or waste stack above the highest fixture connection to the open air — the portion of the stack above the topmost fixture connection becomes a vent pipe that provides air circulation for the entire stack below it

A vent pipe serving only one fixture

A vent pipe connecting multiple stacks at the roof

None

10.

What is the purpose of a 'fire watch' when soldering or using a torch near combustible materials?

What is the purpose of a 'fire watch' when soldering or using a torch near combustible materials?Deselect Answer

A fire watch is required only when using acetylene torches

A designated person (or the worker after completing torch work) who monitors the work area for at least 30–60 minutes after torch work is completed — smoldering fires in wall cavities, insulation, or structural members may not become apparent for 30 minutes to hours after the heat source is removed. Many structure fires start from torch work and are discovered after the tradesperson has left the site

Fire watch is only required in commercial buildings

Fire watch is only required when insurance specifically mandates it

None

11.

What is 'water hammer' and how is it prevented in plumbing systems?

What is 'water hammer' and how is it prevented in plumbing systems?Deselect Answer

Water hammer is low pressure caused by undersized supply pipes

The hydraulic shock caused by sudden stoppage of water flow (as when a solenoid valve or quick-closing valve closes) that creates a pressure wave that travels through the piping — prevented by installing air chambers, water hammer arrestors, or expansion tanks at fixture connections where quick-closing valves are used

Water hammer is caused by excessively hot water in the supply system

Water hammer only occurs in drain lines, not supply lines

None

12.

What is the purpose of 'hydrostatic pressure testing' on a new plumbing system?

What is the purpose of 'hydrostatic pressure testing' on a new plumbing system?Deselect Answer

Testing the plumbing system's resistance to earthquake damage

Filling the system (or a section) with water under static pressure and observing for pressure loss over a specified time — verifying that all joints, fittings, and pipes are leak-free before the system is buried, concealed in walls, or put into service. Required by California Plumbing Code for both supply and drain systems

Testing the water quality in the new plumbing system

A test of water heater capacity

None

13.

What is the purpose of a 'tempering valve' or 'thermostatic mixing valve' (TMV) at a water heater?

What is the purpose of a 'tempering valve' or 'thermostatic mixing valve' (TMV) at a water heater?Deselect Answer

To increase water temperature at distant fixtures

To mix hot water from the heater with cold water to deliver a safe, predetermined temperature at fixtures — required by California law in certain occupancies (care facilities, schools) and recommended for all residential applications to prevent scalding while allowing the water heater to be set higher to control Legionella bacteria

To reduce water pressure from the water heater

To prevent backflow from the hot water system

None

14.

What is the purpose of wearing a 'half-face respirator with organic vapor cartridges' when working with PVC primer and cement in enclosed spaces?

What is the purpose of wearing a 'half-face respirator with organic vapor cartridges' when working with PVC primer and cement in enclosed spaces?Deselect Answer

Respirators are only required for asbestos work — PVC solvents are safe

PVC primer (purple) and cement contain tetrahydrofuran (THF), cyclohexanone, MEK, and acetone — highly volatile organic solvents with OSHA PELs that can be exceeded in poorly ventilated spaces within minutes. The organic vapor cartridges adsorb these solvents before they reach the lungs. In confined areas (crawl spaces, mechanical rooms, pipe chases), solvent vapors can accumulate to hazardous concentrations rapidly

Only a paper dust mask is needed for PVC cement work

PVC solvent vapors are not absorbed through the respiratory tract

None

15.

What is the purpose of 'leak isolation' techniques when a building has a hidden water leak?

What is the purpose of 'leak isolation' techniques when a building has a hidden water leak?Deselect Answer

Leak isolation is only done when the leak is visible

Systematically shutting off sections of the supply system to determine which zone contains the leak — the building is divided into zones by shutting off branch valves and monitoring pressure gauges or water meter movement to locate which branch contains the leak before opening walls or floors

Leak isolation is only done for insurance claims

Leak isolation is only required on commercial buildings

None

16.

What is the purpose of 'pressure testing' supply lines after a repipe before restoring wall finishes?

What is the purpose of 'pressure testing' supply lines after a repipe before restoring wall finishes?Deselect Answer

To verify that the water meter is working correctly

To confirm all joints in the new supply system are leak-free at operating pressure before concealing pipes in walls and ceilings — any leaks must be found and repaired while pipes are accessible. A pressure test failure after walls are closed requires opening the wall again, which is far more expensive than testing before closing

Pressure testing is only required on hot water lines

Pressure testing is required only if the permit inspector requests it

None

17.

What is the proper way to dispose of solvents used to clean PVC pipe joints during installation?

What is the proper way to dispose of solvents used to clean PVC pipe joints during installation?Deselect Answer

Pour excess solvents down the drain — they are diluted by large water volumes

Solvents (PVC primer, PVC cement, ABS cement) are VOC-containing flammable liquids classified as hazardous waste in California — they must be: kept in tightly closed containers when not in use; stored away from heat sources and open flames; used in ventilated areas; and disposed of through a licensed hazardous waste hauler or household hazardous waste collection. Pouring down drains or storm drains is illegal

Allow solvents to evaporate outdoors — this is an approved disposal method

Excess solvents may be buried in the job site trench

None

18.

What is a 'drain, waste, and vent' (DWV) system?

What is a 'drain, waste, and vent' (DWV) system?Deselect Answer

Only the horizontal drain pipes from fixtures to the building sewer

The complete system of pipes that: (1) conveys sewage from fixtures to the sewer (drain and waste); (2) provides air to the system to prevent siphoning of traps and allow sewage to flow freely; (3) allows sewer gases to escape safely to the atmosphere above the roof (vent). DWV is one of the two major plumbing systems (the other being the potable water supply system)

The venting system only — drain pipes are separate

A system for draining rainwater from roofs and exterior areas

None

19.

What does 'as-built drawings' mean at the completion of a plumbing project?

What does 'as-built drawings' mean at the completion of a plumbing project?Deselect Answer

Drawings created before construction showing the planned layout

Updated drawings that reflect all field changes made during construction — showing the actual locations, sizes, and routing of all installed plumbing systems as they were built, not as originally designed. Required by many contracts and often required by code for complex projects

The original architectural drawings used for permitting

Progress drawings submitted for each inspection

None

20.

What is the purpose of wearing safety boots or steel-toed work boots on a plumbing job site?

What is the purpose of wearing safety boots or steel-toed work boots on a plumbing job site?Deselect Answer

Safety boots are only required on commercial construction sites

Steel-toed safety boots protect feet from two primary hazards: (1) impact injury from dropped pipe, fittings, tools, or equipment — a 4-inch cast iron fitting dropped on an unprotected foot can cause serious crushing injury; (2) puncture from nails, wire, or sharp objects on the floor. Cal/OSHA requires appropriate footwear to protect against identified workplace hazards — on most plumbing construction and renovation sites, steel-toed boots are standard required PPE

Safety boots are only required when using power tools

Only non-slip soles are required — steel toes are optional

None

21.

What is 'soft water' and what plumbing considerations does it create?

What is 'soft water' and what plumbing considerations does it create?Deselect Answer

Water with low dissolved oxygen content

Water that has been treated to remove calcium and magnesium ions (water hardness) through ion exchange — soft water is more corrosive to copper and brass fittings than hard water because it is more aggressive at dissolving metals. It may increase copper leaching from pipes and cause pitting corrosion in copper systems

Soft water has lower pressure than hard water

Soft water prevents scale buildup and has no negative plumbing effects

None

22.

When replacing a single fixture in an older building, what code compliance consideration must the plumber address?

When replacing a single fixture in an older building, what code compliance consideration must the plumber address?Deselect Answer

The entire building must be brought up to current code when any work is done

Only the work being performed must comply with current code — the new fixture and its connections must meet current requirements, but the existing system does not need to be upgraded. However, if the existing system presents a safety hazard, the contractor should notify the owner

All plumbing must be replaced whenever one fixture is replaced

The contractor must upgrade all fixtures in the same bathroom

None

23.

A plumbing contractor estimates 120 linear feet of 2-inch copper supply pipe at $4.50 per foot material cost, plus 6 hours of labor at a loaded rate of $95/hr. What is the total cost for this portion of the work?

$1,110

None

24.

What is the first step a plumbing contractor should take when called for a 'no hot water' service call?

What is the first step a plumbing contractor should take when called for a 'no hot water' service call?Deselect Answer

Replace the water heater immediately

Systematically diagnose the problem before performing any work: (1) check if the unit is powered/has gas supply; (2) for gas — check pilot light, gas valve, and thermocouple; (3) for electric — check circuit breaker, heating elements, thermostat; (4) check the temperature setting; (5) for tankless — check error codes; (6) verify the hot water shut-off valve is open. Most 'no hot water' calls are simple diagnostic solutions — not water heater replacements

Drain the water heater before diagnosing

Check the main water supply first

None

25.

What is the purpose of 'ergonomic practices' for plumbers regarding repetitive motion injuries?

What is the purpose of 'ergonomic practices' for plumbers regarding repetitive motion injuries?Deselect Answer

Ergonomics only applies to office workers

Plumbing work involves repetitive motions (pipe threading, tightening fittings) and awkward positions (crouching under sinks, working in crawl spaces) that cause musculoskeletal disorders — ergonomic practices include: using powered pipe threaders instead of manual; using joint compound guns instead of hand-wiping; taking rest breaks; using padded knee pads; adjusting work height; and varying tasks to prevent overuse of specific muscle groups

Ergonomic injuries in plumbing are not covered by workers compensation

All plumbing PPE requirements are limited to hard hats and safety glasses

None

26.

A homeowner complains that a toilet 'runs' continuously. What is the most likely cause?

A homeowner complains that a toilet 'runs' continuously. What is the most likely cause?Deselect Answer

The supply pressure is too low

The flapper valve is worn or misaligned — it fails to seat properly against the flush valve seat, allowing water to continuously leak from the tank into the bowl. This can be heard as a constant trickle sound and confirmed by the dye test (food coloring in the tank that appears in the bowl without flushing)

The vent pipe is blocked

The supply float valve is too high

None

27.

What is the purpose of a 'borescope' or 'inspection camera' in drain service work?

What is the purpose of a 'borescope' or 'inspection camera' in drain service work?Deselect Answer

Cleaning agents applied to remove blockages from drains

A flexible fiber-optic or digital camera inserted into drain pipes to visually inspect the interior — revealing blockage type and location, pipe condition (root intrusion, cracks, corrosion, offset joints), and drain configuration. Allows targeted repair rather than blind digging

A device that applies chemical drain cleaners

An instrument that measures drain slope

None

28.

What type of water heater installation is required in California to reduce risk of gas valve damage and improve safety?

What type of water heater installation is required in California to reduce risk of gas valve damage and improve safety?Deselect Answer

Water heaters must be installed in temperature-controlled rooms

Residential water heaters must be strapped to the wall in two places (upper 1/3 and lower 1/3) using approved seismic strapping to prevent tipping during an earthquake — required by California Health and Safety Code Section 19211. This prevents gas line damage and potential explosion or fire during seismic events

Water heaters must be enclosed in a sealed cabinet

Water heaters must be installed in exterior locations only

None

29.

What California regulation requires plumbing contractors to call 811 before digging?

What California regulation requires plumbing contractors to call 811 before digging?Deselect Answer

None

30.

What is the proper disposal method for lead pipe or lead solder removed during plumbing repair?

What is the proper disposal method for lead pipe or lead solder removed during plumbing repair?Deselect Answer

Lead pipe can be disposed of in regular trash

Lead is a hazardous material regulated by California — lead pipe and lead-based solder removed during renovation must be handled as potentially hazardous waste. Contact the local household hazardous waste program or a licensed hazardous material contractor. Do not melt or burn lead components on site due to toxic fume generation

Lead can be recycled at any metal recycling facility without restrictions

Lead pipe is not hazardous and can be buried on the property

None

31.

What is the purpose of a 'flow restrictor' inside a showerhead and when should it be cleaned or replaced?

What is the purpose of a 'flow restrictor' inside a showerhead and when should it be cleaned or replaced?Deselect Answer

Flow restrictors increase shower pressure by concentrating the stream

A small plastic disc or screen inside the showerhead inlet that limits flow to the maximum rate required by California code (1.8 gpm at 80 PSI) — they should be cleaned when mineral deposits reduce flow below acceptable levels, or removed during service calls when customers have inadequate flow due to clogging from hard water scale

Flow restrictors are only required on commercial showerheads

Flow restrictors are optional accessories that can be added to any showerhead

None

32.

What is the purpose of a 'bid bond' on a commercial plumbing project?

What is the purpose of a 'bid bond' on a commercial plumbing project?Deselect Answer

Guarantees the quality of the plumbing installation

A surety bond submitted with a competitive bid that guarantees the contractor will enter into the contract at the bid price if awarded — if the contractor refuses after award, the bond (typically 10% of bid) compensates the owner for the cost of re-bidding to the next contractor

Guarantees that materials meet specification requirements

Provides insurance coverage during the bidding process

None

33.

What is the purpose of a 'cleanout at the base of a stack'?

What is the purpose of a 'cleanout at the base of a stack'?Deselect Answer

To allow ventilation at the bottom of the soil stack

To provide access for drain cleaning equipment at the base of a vertical drainage stack where horizontal flow begins — this is the most important single cleanout location because it provides access to both the vertical stack above (by pulling cleaning cable up) and the horizontal building drain below. Required by California Plumbing Code at the base of every soil and waste stack

To reduce pressure at the base of tall stacks

To provide an air inlet at the stack bottom

None

34.

What is the purpose of 'cutting in' or 'tapping' an existing drain line when adding a new fixture?

What is the purpose of 'cutting in' or 'tapping' an existing drain line when adding a new fixture?Deselect Answer

Cleaning the existing drain line before connecting

Making a connection into an existing drain pipe to add a new branch — requires: (1) cutting out a section of the existing pipe; (2) installing a wye or tee fitting; (3) connecting the new branch to the fitting. The fitting must be installed with proper orientation (wye for horizontal connections, sanitary tee for vertical stack connections) and the new connection must be vented

Cutting a notch in the pipe to reduce its diameter

Cutting the pipe to prepare for abandonment

None

35.

What is the purpose of a 'pressure reducing valve' (PRV) in a residential plumbing system?

What is the purpose of a 'pressure reducing valve' (PRV) in a residential plumbing system?Deselect Answer

To increase water pressure to fixtures on upper floors

To reduce incoming street water pressure to a safe working pressure (typically 60–80 PSI) for the building's plumbing system — required when incoming pressure exceeds 80 PSI per California Plumbing Code

To prevent backflow from the building into the water main

To regulate hot water temperature at fixtures

None

36.

What is the minimum size required for a building sewer serving a residential building with two full bathrooms?

What is the minimum size required for a building sewer serving a residential building with two full bathrooms?Deselect Answer

2-inch pipe

3-inch pipe

4-inch pipe

6-inch pipe

None

37.

What is the purpose of a 'fixture unit' (DFU) in plumbing system design?

What is the purpose of a 'fixture unit' (DFU) in plumbing system design?Deselect Answer

A measurement of water pressure at each fixture

A weighted value assigned to each fixture that represents its relative demand on the drainage system — used to size drain, waste, and vent piping

A unit of hot water demand for water heater sizing

A measurement of water supply pressure required

None

38.

What is the total charge for four 8-hour days' use of a backhoe if rental cost is $400 per day and the operator cost is $70 per hour?

What is the total charge for four 8-hour days' use of a backhoe if rental cost is $400 per day and the operator cost is $70 per hour?Deselect Answer

$5,440

$3,840

$2,640

$2,160

None

39.

What is the purpose of 'backflow prevention' in plumbing systems?

What is the purpose of 'backflow prevention' in plumbing systems?Deselect Answer

To prevent water from flowing backward out of a fixture drain

To protect the potable water supply from contamination by preventing the reversal of flow from a contaminated source back into the potable supply — required at all cross-connections between potable water and non-potable sources (irrigation, industrial equipment, health hazard connections)

To prevent air from entering water supply pipes

To prevent sewer gas from entering the building

None

40.

What is a 'bidet' and what special plumbing requirements does its installation require?

What is a 'bidet' and what special plumbing requirements does its installation require?Deselect Answer

A bidet is a type of bathtub used in European plumbing

A bidet is a low-mounted plumbing fixture for personal hygiene after toilet use — it requires hot and cold supply connections at specific rough-in locations, a drain connection, and typically a vacuum breaker or backflow prevention on the sprayer/handshower connection because the fixture's water may be contaminated by its use and could siphon back into the supply

Bidets only require a cold water connection

Bidets can be installed anywhere a toilet is installed without special considerations

None

41.

What is the required test for underground drainage piping before backfilling?

What is the required test for underground drainage piping before backfilling?Deselect Answer

Air pressure test at 15 PSI for 15 minutes

Water test — fill the system to the level of the highest stack and hold for 15 minutes with no observed leakage, OR air test at 5 PSI for 15 minutes per California Plumbing Code

Smoke test only

Visual inspection only — no pressure test required

None

42.

What is the purpose of a 'pressure balance valve' in a shower?

What is the purpose of a 'pressure balance valve' in a shower?Deselect Answer

To increase water pressure for a more forceful shower stream

To automatically maintain the ratio of hot and cold water when pressure fluctuates elsewhere in the system — preventing scalding when cold water demand elsewhere (toilet flush, dishwasher) suddenly reduces cold water pressure at the shower. Required by California Plumbing Code for all new shower installations

To reduce water pressure at the showerhead below code maximum

To provide a separate shut-off for the shower

None

43.

What is 'wet venting' in plumbing system design?

What is 'wet venting' in plumbing system design?Deselect Answer

Venting pipes that are exposed to rain and outdoor conditions

A vent pipe that also serves as a drain pipe for another fixture — allowing a single pipe to serve both drainage and venting functions for properly sized and configured fixture groups, reducing the total pipe required

Installing vent pipes under water during underground construction

A type of vent required in wet climates

None

44.

What is the purpose of 'repipe' work in older residential buildings?

What is the purpose of 'repipe' work in older residential buildings?Deselect Answer

Replacing only the fixtures in an older home

Replacing all or a significant portion of the original supply piping system — typically galvanized steel (which corrodes internally over 30–50 years, reducing flow and leaching rust) with modern copper or CPVC/PEX plastic. Repipe projects typically include replacing all supply branches from the main to each fixture with new material and valves

Repipe refers only to replacing drain pipes

Repipe work is only done on commercial buildings

None

45.

What is 'surge pressure' in a water supply system and what causes it?

What is 'surge pressure' in a water supply system and what causes it?Deselect Answer

The normal operating pressure of the supply system

A transient pressure spike that exceeds the working pressure of the system — caused by sudden valve closing, pump startup or shutdown, or the reflection of water hammer pressure waves. Surge pressure can be 2–10× the normal operating pressure and can rupture pipes or damage valve seats

Surge pressure is the same as water hammer

Surge pressure only occurs in hot water systems

None

46.

What is the purpose of coordination drawings in multi-trade commercial construction?

What is the purpose of coordination drawings in multi-trade commercial construction?Deselect Answer

They replace the need for shop drawings on large projects

Combined drawings showing all mechanical, electrical, plumbing, and structural systems in the same space — used to identify and resolve conflicts (where one trade's pipe would intersect another's duct or structure) before installation, preventing costly field rework

Coordination drawings are submitted for permit only

Required only when a project has more than 5 subcontractors

None

47.

What is the proper method for isolating a section of copper pipe that needs to be repaired?

What is the proper method for isolating a section of copper pipe that needs to be repaired?Deselect Answer

Kink the pipe upstream of the repair to stop flow

Turn off the appropriate shut-off valve serving that section; open faucets downstream to relieve pressure and drain remaining water; dry the pipe section completely (propane torch to remove moisture for soldering, or mechanical means for press fittings); make the repair; test for leaks before closing the wall or restoring service

Wrap the pipe with tape while water is still flowing

Replace the entire supply system whenever a repair is needed

None

48.

What is the correct immediate response when a plumber cuts into a pipe and discovers asbestos-containing pipe insulation?

What is the correct immediate response when a plumber cuts into a pipe and discovers asbestos-containing pipe insulation?Deselect Answer

Remove the asbestos insulation carefully and dispose of it in trash

Stop work immediately — do not disturb the material further. Secure the area, notify the building owner, and contact a California-licensed asbestos abatement contractor to evaluate and remove the material before plumbing work continues. Do not attempt to remove asbestos pipe insulation yourself — it is a regulated hazardous material requiring special training, equipment, and disposal procedures

Wet the insulation and continue working — water prevents asbestos fiber release

Wrap the asbestos insulation in plastic and continue the repair

None

49.

When adding a new bathroom in a basement below the municipal sewer main elevation, what system is required?

When adding a new bathroom in a basement below the municipal sewer main elevation, what system is required?Deselect Answer

Standard gravity drain — the building drain can still flow to the sewer

A sewage ejector (grinder pump) system — a sealed pit containing a pump that grinds waste and pumps it up to the elevation of the sewer main. The pump activates automatically when the pit reaches a set level. Required by California Plumbing Code when drainage cannot flow by gravity to the building sewer or public main

A chemical treatment system that dissolves waste on-site

Basement bathrooms are not permitted in California

None

50.

What is the maximum temperature setting for a water heater thermostat in a residential building to prevent scalding?

What is the maximum temperature setting for a water heater thermostat in a residential building to prevent scalding?Deselect Answer

110°F

120°F

130°F

140°F

None

51.

What type of wall fitting should a contractor use to install a wall-mounted water closet?

What type of wall fitting should a contractor use to install a wall-mounted water closet?Deselect Answer

A hubless closet ring

An approved spud fitting

An approved closet flange

An approved carrier fitting

None

52.

What is a 'P-trap' and what is its function in a plumbing system?

What is a 'P-trap' and what is its function in a plumbing system?Deselect Answer

A pressure trap that prevents high water pressure at fixtures

A U-shaped or P-shaped trap installed below every fixture drain outlet — the trap holds a water seal that prevents sewer gases from entering the building through the drain opening. The water seal is maintained by the weight of water and must be replenished by normal fixture use

A trap that prevents backflow in pressurized water supply lines

A trap for catching hair and debris at sink drains

None

53.

What is a 'combination waste and vent system' under the California Plumbing Code?

What is a 'combination waste and vent system' under the California Plumbing Code?Deselect Answer

A system where wastewater and stormwater share the same pipe

A special system using oversized, nearly horizontal drainage pipes that carry both the waste flow and the air needed for venting in the same pipe — permitted for specific limited applications (typically horizontal fixtures in flat-slab commercial construction where traditional venting would be impractical). Sometimes called an 'air circulation system'

A system combining greywater and blackwater in one pipe

Combination waste and vent is the standard system for all buildings

None

54.

What is the purpose of a 'house trap' or 'building trap' in an older sewer system?

What is the purpose of a 'house trap' or 'building trap' in an older sewer system?Deselect Answer

A trap installed at each fixture connection

A large trap installed at the building sewer connection to the public sewer — intended to prevent sewer gases from entering the building through the public sewer. Modern plumbing codes no longer require building traps because properly trapped fixtures and a well-vented DWV system prevent sewer gas entry without a main trap

A backwater valve preventing sewer backup

A cleanout installed at the foundation wall

None

55.

What is the purpose of 'ground fault circuit interrupter' (GFCI) protection for electrical outlets near plumbing fixtures?

What is the purpose of 'ground fault circuit interrupter' (GFCI) protection for electrical outlets near plumbing fixtures?Deselect Answer

GFCI outlets provide surge protection for electronic equipment in bathrooms

GFCI outlets near water sources (sinks, tubs, showers) shut off power within 1/40 second when they detect a current leakage of 5 mA or more — preventing electrocution when a person using electrical equipment near water creates a ground fault. California Electrical Code requires GFCI protection within 6 feet of any sink, in bathrooms, kitchens, garages, outdoors, and near other wet locations. While not a plumbing code requirement, plumbers must coordinate with electricians on GFCI locations

GFCI protection is only required in commercial buildings

GFCI protection is only required for 240-volt circuits

None

56.

When reading a plumbing plan, what does a dashed line typically represent?

When reading a plumbing plan, what does a dashed line typically represent?Deselect Answer

A cold water supply line

A pipe located above the floor (overhead) or concealed in the ceiling — dashed lines distinguish overhead piping from below-floor or in-wall piping shown as solid lines

An abandoned pipe that is no longer in service

A hot water return line

None

57.

What are 'trim out' or 'set' operations in residential plumbing?

What are 'trim out' or 'set' operations in residential plumbing?Deselect Answer

Rough plumbing installation before walls are closed

The final phase of plumbing installation after finish surfaces are complete — setting and connecting fixtures (toilets, faucets, sinks, tubs, disposals, dishwashers), making final supply connections, installing trim pieces, and testing all systems. The trim out completes the project after rough plumbing and inspections are done

Cutting and trimming pipe to length during rough-in

Inspections performed after rough plumbing

None

58.

What is 'horizontal wet venting' and when is it permitted under the California Plumbing Code?

What is 'horizontal wet venting' and when is it permitted under the California Plumbing Code?Deselect Answer

Horizontal wet venting is never permitted in California

A system where a horizontal drain pipe also serves as a vent for one or more fixtures — permitted for bathroom groups (toilet, lavatory, tub/shower) within specific pipe size and distance limitations. The wet vent must be oversized to handle both drainage flow and the venting function simultaneously

Horizontal wet venting only applies to commercial buildings

Horizontal wet venting requires a permit from the state plumbing board

None

59.

What is the purpose of calling 811 (Underground Service Alert) before any excavation?

What is the purpose of calling 811 (Underground Service Alert) before any excavation?Deselect Answer

To get a permit for excavation work

To have underground utilities (gas, electric, water, telecom) located and marked before digging — preventing utility strikes that can cause electrocution, gas explosions, water service disruptions, and telecom outages. Required by California Government Code 4216 — failure to call is a serious liability and CSLB violation

To notify neighbors of planned construction

To register the excavation with the city building department

None

60.

What is 'water conservation' requirement CalGreen (California Green Building Standards Code) imposes on new residential plumbing installations?

What is 'water conservation' requirement CalGreen (California Green Building Standards Code) imposes on new residential plumbing installations?Deselect Answer

No specific water conservation requirements apply to residential plumbing

CalGreen mandates low-flow fixtures including: toilets ≤1.28 gpf, lavatory faucets ≤1.2 gpm, showerheads ≤1.8 gpm (2 gpm for larger showers), and kitchen faucets ≤1.8 gpm — significantly below federal standard levels to reduce water consumption in California's water-stressed environment

CalGreen only applies to commercial plumbing systems

Water conservation requirements are voluntary in California

None

61.

What personal protective equipment is required when soldering copper pipe with a torch?

What personal protective equipment is required when soldering copper pipe with a torch?Deselect Answer

No PPE is required for soldering — it is a low-risk activity

Safety glasses or face shield to protect eyes from hot solder splatter and flux fumes; leather gloves to protect hands from heat; a fire-resistant cloth or metal heat shield placed behind the solder joint to protect combustible framing or wall materials from torch flame — and a fire extinguisher within reach

Only gloves are required for torch soldering

Steel-toed boots are the only required PPE for plumbing work

None

62.

What is the correct procedure when a plumber discovers an unexpected gas leak during work on a plumbing system?

What is the correct procedure when a plumber discovers an unexpected gas leak during work on a plumbing system?Deselect Answer

Ignore small gas leaks — they are acceptable in older buildings

Immediately evacuate the building, do not operate any electrical switches or open flames, leave doors open if safe to do so, call the gas utility emergency line from outside the building, and keep everyone away from the building until the gas company responds and secures the leak. Do not attempt to repair a gas leak yourself unless you are qualified and have the proper equipment to do so safely

Light a match to identify where the gas is coming from

Continue working if the smell is faint — call the utility later

None

63.

What Cal/OSHA regulation requires a written Injury and Illness Prevention Program (IIPP) for plumbing contractors?

What Cal/OSHA regulation requires a written Injury and Illness Prevention Program (IIPP) for plumbing contractors?Deselect Answer

No IIPP is required for small plumbing contractors

Cal/OSHA Title 8, Section 3203 requires ALL California employers (regardless of size) to have a written Injury and Illness Prevention Program — covering: hazard identification, investigation procedures, corrective actions, training, and worker communication. The IIPP must be available at the job site and reviewed annually

IIPP is only required for contractors with more than 10 employees

IIPP is only required for contractors doing public works

None

64.

What is a 'closet flange' and what are the requirements for its installation?

What is a 'closet flange' and what are the requirements for its installation?Deselect Answer

A decorative collar around the visible portion of the toilet supply tube

A round fitting installed at the termination of the toilet drain (closet bend) at the floor level — it provides the structural connection between the toilet and the drain pipe, and the surface to which the toilet is bolted. The top of the flange must be at the finished floor level per California Plumbing Code

A valve controlling the toilet supply

The connection between the toilet tank and bowl

None

65.

When replacing a section of galvanized steel drain pipe with ABS plastic, what fitting is used to connect the two materials?

When replacing a section of galvanized steel drain pipe with ABS plastic, what fitting is used to connect the two materials?Deselect Answer

Threaded coupling directly connecting galvanized to ABS

A 'mission coupling' or rubber fernco coupling (rubber sleeve with stainless steel clamps) — this flexible connector allows connection between different pipe materials and sizes without requiring threading or special tools. The rubber sleeve slips over both pipe ends and the stainless clamps are tightened to create a watertight connection

The galvanized must be cut and a new ABS fitting threaded on

PVC cement applied directly between the two materials

None

66.

When installing a water filtration system for domestic use, what is commonly used for taste and odor control?

When installing a water filtration system for domestic use, what is commonly used for taste and odor control?Deselect Answer

Lime

Carbon

Nitrogen

Copper sulphate

None

67.

What is the purpose of 'repiping with PEX' versus copper when repiping an older residential building?

What is the purpose of 'repiping with PEX' versus copper when repiping an older residential building?Deselect Answer

PEX requires more fittings than copper, making it always more expensive

Cross-linked polyethylene (PEX) tubing offers several advantages for repipe work: flexible tubing can be fished through walls with fewer openings than rigid copper; it is freeze-resistant (expands instead of bursting); it does not corrode in aggressive water; it is less expensive than copper; and PEX expansion or crimp connections are made without open flame, reducing fire risk. Disadvantages: cannot be used outdoors exposed to UV; requires transition fittings to connect to existing copper

PEX provides lower water quality than copper pipe

PEX is prohibited by the California Plumbing Code for potable water systems

None

68.

What is the minimum burial depth for a water service pipe in a non-traffic area under California Plumbing Code?

What is the minimum burial depth for a water service pipe in a non-traffic area under California Plumbing Code?Deselect Answer

6 inches

12 inches

18 inches

24 inches

None

69.

What is the purpose of a 'fixture schedule' on plumbing drawings?

What is the purpose of a 'fixture schedule' on plumbing drawings?Deselect Answer

A list of the plumbing contractor's scheduled work days

A table on the drawings that identifies each plumbing fixture by symbol, manufacturer, model number, and specification — allowing the installer to know exactly which fixtures are required in each location

A permit application schedule submitted to the building department

The inspection schedule for the plumbing system

None

70.

What is the purpose of a 'trench box' (trench shield) during underground plumbing installation?

What is the purpose of a 'trench box' (trench shield) during underground plumbing installation?Deselect Answer

A trench box is a metal container for transporting pipe in a trench

A protective steel or aluminum box lowered into a trench that provides cave-in protection for workers installing underground piping — workers work inside the box while it is moved along the trench as work progresses. The box does not prevent cave-in but protects workers inside from being crushed by any cave-in that occurs outside the box

Trench boxes are used to store pipe during installation

Trench boxes are decorative markers indicating underground pipe locations

None

71.

What is the purpose of a 'cleanout' in a drainage system?

What is the purpose of a 'cleanout' in a drainage system?Deselect Answer

A device to clean sediment from potable water supply pipes

An access fitting installed in drain lines that allows a drain cleaning machine or hand snake to be inserted to clear blockages — required at specific intervals and locations by the California Plumbing Code

A fitting used to clean pipe threads during installation

An air vent at the high point of a drain line

None

72.

What is the minimum vent size for a water closet?

What is the minimum vent size for a water closet?Deselect Answer

1.25-inch pipe

1.5-inch pipe

2-inch pipe

3-inch pipe

None

73.

What is the purpose of 'lockout/tagout' (LOTO) procedures for plumbing service on pressurized systems?

What is the purpose of 'lockout/tagout' (LOTO) procedures for plumbing service on pressurized systems?Deselect Answer

LOTO is only for electrical systems — not applicable to plumbing

LOTO procedures for plumbing: (1) identify and close all supply valves to the affected system; (2) lock the valve in the closed position with a personal padlock so no other worker can unknowingly restore pressure; (3) tag the lock with the worker's name and reason; (4) relieve residual pressure by opening a downstream fixture; (5) verify the system is depressurized before opening any connections. This prevents unexpected pressurization of open pipes, which can cause serious injury

LOTO is only required on systems operating above 100 PSI

LOTO is only required when multiple trades are working simultaneously

None

74.

What is a 'wet wall' in construction terms?

What is a 'wet wall' in construction terms?Deselect Answer

A wall that is damp due to moisture problems

A wall containing plumbing pipes (supply and drain) — typically the wall behind a bathtub, behind a toilet, or a common wall between bathrooms. Wet walls are typically built with 2×6 framing instead of 2×4 to accommodate the larger drain pipes

A wall constructed in a wet environment

A wall with waterproof finish on the interior

None

75.

What is the minimum slope required for a 4-inch horizontal drainage pipe per the California Plumbing Code?

What is the minimum slope required for a 4-inch horizontal drainage pipe per the California Plumbing Code?Deselect Answer

1/16 inch per foot

1/8 inch per foot

1/4 inch per foot

1/2 inch per foot

None

76.

A plumbing contractor submits a bid for a project. Direct costs are $18,000. Overhead is 15% of direct costs and profit is 12% of direct costs. What is the total bid price?

A plumbing contractor submits a bid for a project. Direct costs are $18,000. Overhead is 15% of direct costs and profit is 12% of direct costs. What is the total bid price?Deselect Answer

$22,860

$23,580

$22,680

$24,120

None

77.

What type of pipe joint is commonly used for underground cast iron soil pipe (hub and spigot)?

What type of pipe joint is commonly used for underground cast iron soil pipe (hub and spigot)?Deselect Answer

Solvent cement joint

Mechanical compression gasket joint (rubber gasket in the hub)

Threaded joint

Lead and oakum caulked joint

None

78.

What is the minimum clearance required in front of a water closet (toilet) per California Plumbing Code?

What is the minimum clearance required in front of a water closet (toilet) per California Plumbing Code?Deselect Answer

12 inches

18 inches

21 inches

24 inches

None

79.

What is the minimum number of fixture units a lavatory (bathroom sink) is assigned for drainage purposes?

What is the minimum number of fixture units a lavatory (bathroom sink) is assigned for drainage purposes?Deselect Answer

1 DFU

2 DFU

3 DFU

4 DFU

None

80.

What is the purpose of 'descaling' a water heater tank or heat exchanger periodically?

What is the purpose of 'descaling' a water heater tank or heat exchanger periodically?Deselect Answer

Descaling is only required on commercial water heating systems

Hard water causes calcium carbonate to precipitate and accumulate on the tank bottom and heating elements (electric) or heat exchanger surfaces — this scale insulates the heating surface, reducing efficiency and increasing energy consumption. Descaling (flushing with dilute citric acid or vinegar, or mechanical removal) restores heat transfer efficiency and extends water heater life

Descaling removes rust from the outside of the water heater tank

Descaling is done only when replacing the water heater anode rod

None

81.

What does a 'shop drawing' submitted by a plumbing contractor typically show?

What does a 'shop drawing' submitted by a plumbing contractor typically show?Deselect Answer

The permit application for the project

Fabrication details, dimensions, materials, and installation information for plumbing assemblies — submitted for review and approval by the engineer or architect before fabrication or installation

The final as-built conditions after installation

The project schedule and milestones

None

82.

What is the primary California code governing plumbing installations for C-36 contractors?

What is the primary California code governing plumbing installations for C-36 contractors?Deselect Answer

2022 California Building Code

2022 California Plumbing Code

2022 California Mechanical Code

2022 California Green Building Standards Code

None

83.

What is the purpose of a 'sanitary tee' versus a 'wye' fitting in a drainage system?

What is the purpose of a 'sanitary tee' versus a 'wye' fitting in a drainage system?Deselect Answer

They are interchangeable — use whichever is available

A sanitary tee (sanitary tee) is used for vertical-to-horizontal connections (stack to branch); a wye (Y) fitting is used for horizontal-to-horizontal connections. Using a sanitary tee for horizontal connections would create a back-cut that traps solids and causes blockages — wyes have a gradual sweeping entry that allows solids to flow smoothly

Sanitary tees are used for vent connections only

Wyes are only used for building sewer connections

None

84.

What is a 'sacrificial anode rod' in a water heater and when should it be replaced?

What is a 'sacrificial anode rod' in a water heater and when should it be replaced?Deselect Answer

An anode rod is the heating element in an electric water heater

A magnesium or aluminum rod suspended inside the water heater tank that corrodes preferentially to protect the steel tank from electrochemical (galvanic) corrosion — the rod 'sacrifices' itself so the tank does not corrode. It should be inspected every 3–5 years and replaced when more than 50% depleted (core wire exposed). In areas with soft or treated water, anode rods deplete faster

Anode rods are only present in commercial water heaters

Anode rods regulate the water temperature inside the tank

None

85.

What is the Cal/OSHA requirement for shoring or sloping of trenches deeper than 5 feet?

What is the Cal/OSHA requirement for shoring or sloping of trenches deeper than 5 feet?Deselect Answer

No requirements apply until trenches reach 10 feet deep

Cal/OSHA Title 8, Section 1541 requires trenches and excavations deeper than 5 feet in depth to be either: sloped at the correct angle for the soil type (maximum 1.5H:1V for Type C soil — the most common and least stable); shored with approved shoring systems; or protected by a trench box (trench shield). Unprotected excavations over 5 feet are one of the leading causes of construction fatalities

Trenches must be shored only when they exceed 10 feet

Workers may enter unprotected trenches up to 8 feet deep if there are no signs of soil instability

None

86.

What is a 'thermal expansion test' on a water heater?

What is a 'thermal expansion test' on a water heater?Deselect Answer

Testing the water heater's heating elements for efficiency

Checking whether the system is closed (by observing pressure rise after heating) — in a closed system, pressure rises when the water heater heats cold water. This test identifies whether an expansion tank is needed. If pressure rises above the relief valve setting during normal operation, an expansion tank is required

A test of the water heater's insulation quality

Testing the pressure relief valve on the water heater

None

87.

When using chemical drain cleaners (caustic soda, sulfuric acid), what safety precautions are required?

When using chemical drain cleaners (caustic soda, sulfuric acid), what safety precautions are required?Deselect Answer

Chemical drain cleaners are always safe for homeowner or contractor use

Chemical drain cleaners require significant safety precautions: safety glasses or face shield (caustic soda and sulfuric acid cause severe eye and skin burns); rubber gloves; adequate ventilation (fumes are hazardous); knowledge of the SDS for the specific product; never mix different drain cleaners (acid + base reaction is violently exothermic); and proper disposal of containers per hazardous waste regulations

Only gloves are required — chemical drain cleaners have mild chemistry

Chemical drain cleaners can be used without PPE if the label says 'safe for use'

None

88.

What is the purpose of ventilating a confined space before a plumber enters to work on a drain system?

What is the purpose of ventilating a confined space before a plumber enters to work on a drain system?Deselect Answer

To reduce the temperature for worker comfort

Sewer systems generate toxic and flammable gases including hydrogen sulfide (H2S), methane, and carbon dioxide — these gases can accumulate to lethal concentrations in manholes, vaults, large diameter pipe, and other confined spaces. Ventilation (forced air supply with a blower) dilutes these gases before and during worker entry. Atmospheric testing is required before entry to verify safe oxygen levels and absence of flammable/toxic gases

Ventilation is only required when using chemical drain cleaners

Ventilation only applies to permit-required confined spaces in commercial settings

None

89.

What is the maximum water pressure allowed at a fixture in a California residential building?

What is the maximum water pressure allowed at a fixture in a California residential building?Deselect Answer

60 PSI

80 PSI

100 PSI

120 PSI

None

90.

What is the purpose of a 'Roman tub faucet' or 'deck-mounted tub filler' versus a wall-mounted tub spout?

What is the purpose of a 'Roman tub faucet' or 'deck-mounted tub filler' versus a wall-mounted tub spout?Deselect Answer

Deck-mounted fillers are decorative only with no functional difference

A deck-mounted tub filler mounts directly on the rim of a freestanding or drop-in tub — the controls and spout emerge from the tub deck or a platform. It requires supply rough-in through the tub deck or platform rather than through the wall, and typically provides a higher flow rate (10–15 gpm) for faster tub filling than standard wall-mounted spouts. Correct rough-in placement is critical — the deck-mounted filler cannot be moved after installation without retiling

Deck-mounted fillers require lower water pressure than wall-mounted spouts

Wall-mounted spouts are required by California code for all tubs

None

91.

What is the purpose of a 'sewer smoke test' in building drainage diagnosis?

What is the purpose of a 'sewer smoke test' in building drainage diagnosis?Deselect Answer

To add fragrance to the drainage system

Introducing theatrical smoke (non-toxic) into the drainage system under slight pressure to locate: failed traps (smoke exits fixtures), cracked or broken pipes (smoke exits ground or walls), poorly sealed clean-outs, and improperly installed fixtures. The smoke reveals leaks in the DWV system that would allow sewer gas to enter the building

A smoke test determines drainage pipe slope

A smoke test is only performed by building departments

None

92.

What is the purpose of 'isometric drawings' used in plumbing design?

What is the purpose of 'isometric drawings' used in plumbing design?Deselect Answer

They show the plumbing system from above (plan view) only

Three-dimensional drawings that show the plumbing system in a pictorial view that reveals the vertical and horizontal routing of all pipes simultaneously — allowing the reader to understand the three-dimensional layout from a single drawing without reading multiple cross-sections

Isometric drawings show only the drain system, not the supply system

They are only used for permit applications

None

93.

What is the purpose of a 'vacuum breaker' on a hose bibb?

What is the purpose of a 'vacuum breaker' on a hose bibb?Deselect Answer

To prevent water hammer when the hose is connected

A backflow prevention device that prevents non-potable water (from a hose, garden, pool, or irrigation system) from being siphoned back into the potable water supply when negative pressure occurs in the supply pipe — required on all hose bibbs by California Plumbing Code

To regulate water pressure at the hose connection

To prevent freezing in cold climates

None

94.

What does California Government Code 4216 require before excavating for underground plumbing?

What does California Government Code 4216 require before excavating for underground plumbing?Deselect Answer

A building permit must be posted at the job site

The contractor must call 811 (Underground Service Alert) at least 2 working days before excavating to have all underground utilities located and marked — failure to comply can result in utility strikes, personal injury, service disruptions, and CSLB disciplinary action

A city engineer must be present during all excavation

Excavation is only permitted between 8 AM and 5 PM

None

95.

What is the purpose of 'escutcheon plates' in plumbing finish work?

What is the purpose of 'escutcheon plates' in plumbing finish work?Deselect Answer

They provide structural support for wall-mounted fixtures

Decorative cover plates that hide the rough opening or pipe penetration through finished walls, floors, or ceilings — concealing the gap between the pipe or fitting and the finished surface for an aesthetically clean installation

They provide a watertight seal around pipes penetrating walls

They are required to meet fire separation requirements at pipe penetrations

None

96.

What is the required cover depth for a water service pipe crossing under a driveway subject to vehicular traffic?

What is the required cover depth for a water service pipe crossing under a driveway subject to vehicular traffic?Deselect Answer

6 inches

12 inches

18 inches

24 inches

None

97.

What is the purpose of an 'access panel' in a plumbing installation?

What is the purpose of an 'access panel' in a plumbing installation?Deselect Answer

A service opening in the building envelope for utility access

A removable panel in a wall, ceiling, or floor that allows access to concealed plumbing valves, cleanouts, shut-off valves, or inspection ports — required by California Plumbing Code in locations where maintenance access is needed but permanent openings are undesirable

An access panel is a decorative feature for exposed pipe installations

Access panels are only required in commercial buildings

None

98.

What type of material is permitted for underground gas piping in California?

What type of material is permitted for underground gas piping in California?Deselect Answer

Standard black steel pipe without coating

Polyethylene (PE) plastic pipe conforming to ASTM D 2513, or steel pipe with approved corrosion protection — PE is most common for underground residential gas service in California. Yellow polyethylene is the standard color for fuel gas

PVC drain pipe can be used for buried gas lines

Copper tubing is the preferred material for all underground gas piping

None

99.

When installing plastic (PVC or ABS) underground drain pipe, what is the purpose of bedding material?

When installing plastic (PVC or ABS) underground drain pipe, what is the purpose of bedding material?Deselect Answer

Bedding is only cosmetic — it does not affect pipe performance

Bedding (clean sand or gravel) placed beneath and around the pipe provides uniform support along the pipe's full length — preventing point loading from rocks or hard soil that causes cracking, and ensuring proper deflection control for flexible plastic pipe that requires distributed side support to maintain its circular cross-section under backfill loading

Bedding is only required under roadways

Bedding material prevents pipe corrosion

None

100.

What is the purpose of a 'trap primer' in floor drain trap installations?

What is the purpose of a 'trap primer' in floor drain trap installations?Deselect Answer

A chemical cleaner added to the trap periodically

A device that periodically introduces a small amount of water into seldom-used floor drain traps to replenish the trap seal before it evaporates — without periodic replenishment, the water seal evaporates, allowing sewer gases to enter the occupied space through the floor drain

A primer coat applied before installing plastic traps

A valve controlling the water pressure in the trap

None

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