Journeyman Plumber (UPC/IPC) — All Questions

A water closet is being roughed in against a side partition in a narrow alcove. Measuring from the finished face of the partition to the center of the closet outlet, what is the minimum dimension the model plumbing codes require?

• a.12 inches
• b.14 inches
• c.18 inches
• d.15 inches✓

The centerline of a water closet must be at least 15 inches from any side wall, partition, or vanity, which is what makes a 30 inch wide alcove the practical minimum for a single fixture. The 12 inch figure is the standard rough-in distance from the finished back wall to the closet flange center, not a side clearance. 14 inches and 18 inches are not code minimums; 18 inches is a common designer's comfort dimension and 14 inches is simply short of the requirement.IPC §405.3.1

Two water closets are to be installed side by side in a school restroom. What is the minimum distance between the centerline of one closet and the centerline of the adjacent closet?

• a.36 inches
• b.24 inches
• c.21 inches
• d.30 inches✓

Because each closet needs 15 inches of clearance on each side of its centerline, two adjacent closets require 15 plus 15, or 30 inches center to center. The 24 inch and 21 inches figures are front clearance numbers, not lateral spacing. 36 inches exceeds the requirement and would be an accessibility compartment width rather than the general fixture spacing minimum.

A framed water closet compartment measures 32 inches wide inside the finished surfaces, and the closet is set exactly on the center of that width. Does the installation satisfy the side clearance requirement?

• a.No, the centerline is only 15 inches from each side and 16 inches is required
• b.Yes, the centerline is 16 inches from each side, which exceeds the 15 inch minimum✓
• c.Yes, but only because a compartment is exempt from side clearance rules
• d.No, a compartment must be at least 36 inches wide in all cases

Half of 32 inches is 16 inches, so each side has 16 inches of clearance from the centerline, one inch more than the 15 inch minimum. The requirement is 15 inches, not 16, so the first choice reverses the numbers. Compartments are not exempt from clearance rules, and 36 inches is an accessible-stall dimension rather than a universal minimum.

Under the International Plumbing Code, what is the minimum clear space required in front of a water closet, measured from the front edge of the fixture to any wall or obstruction?

• a.24 inches
• b.15 inches
• c.21 inches✓
• d.30 inches

The IPC requires 21 inches of clear space in front of a water closet, lavatory, or bidet, although some jurisdictions and the UPC require 24 inches. 15 inches is the side clearance from the centerline, not a front dimension. 30 inches is the center-to-center spacing between two closets and has nothing to do with front approach space.IPC §405.3.1

A building owner replaces 40 old 3.5 gpf water closets with 1.28 gpf high efficiency models. If the fixtures are flushed a combined total of 2,000 times per day, how much water is saved per day?

• a.5,120 gallons
• b.3,500 gallons
• c.4,440 gallons✓
• d.2,560 gallons

The savings per flush is 3.5 minus 1.28, or 2.22 gallons, and 2.22 times 2,000 flushes equals 4,440 gallons per day. 2,560 gallons is 1.28 times 2,000, the new consumption rather than the savings. 5,120 and 3,500 gallons come from doubling the new usage or from using the old flush volume alone, neither of which is a difference calculation.IPC §604.4

A storage type water heater is being installed. Which device must be provided on the tank to protect against both excessive temperature and excessive pressure?

• a.A backflow preventer on the cold water inlet
• b.A vacuum relief valve at the top of the tank
• c.A pressure reducing valve on the building supply
• d.A combination temperature and pressure relief valve✓

Every storage water heater must be equipped with an approved combination temperature and pressure relief valve, typically rated to open at 210 degrees F and 150 psi. A vacuum relief valve prevents siphoning of the tank on bottom-fed heaters but does not relieve pressure or temperature. A backflow preventer and a pressure reducing valve address contamination and supply pressure, not tank overpressure or overheating.IPC §504.4

A temperature and pressure relief valve has a 3/4 inch outlet. Which discharge piping arrangement is acceptable?

• a.3/4 inch pipe running by gravity to terminate 8 inches above the floor with a plain end✓
• b.1/2 inch copper reduced at the valve and terminating 30 inches above the floor
• c.3/4 inch pipe with a threaded cap installed on the terminal end
• d.3/4 inch pipe with a ball valve installed for service isolation

Discharge piping must be full size of the valve outlet with no reduction, must drain by gravity, must have no valve in the line, and must terminate between 6 and 24 inches above the ground or an approved receptor with no threads on the end. The 1/2 inch option reduces the pipe and terminates too high, the ball valve option installs a prohibited shutoff, and the threaded cap option both threads the end and blocks discharge entirely.IPC §504.6

A 50 gallon water heater is installed in the attic above a finished ceiling. A drain pan is required. What is the minimum size of the pan drain line?

• a.3/4 inch✓
• b.1 inch
• c.5/8 inch
• d.1/2 inch

Where leakage would cause damage to the structure, a pan is required and its indirect drain must be at least 3/4 inch in diameter, discharging to an approved location. 1/2 inch and 5/8 inch are undersized and would not carry the flow of a leaking tank. A 1 inch pan drain is permitted as an upsize but is not the code minimum being asked for.IPC §504.7

A gas fired water heater is installed in a residential garage in a seismic zone. It must be strapped in two places. Where must the lower strap be located relative to the heater's controls?

• a.At least 4 inches above the controls✓
• b.At least 4 inches below the controls
• c.At the exact vertical midpoint of the tank
• d.Directly across the control housing

The two straps go around the upper third and the lower third of the tank, and the lower strap must be at least 4 inches above the controls so the strap does not damage or obstruct the gas valve and thermostat. Strapping across or below the controls interferes with service and with the control housing itself. A single midpoint strap does not satisfy the two-point bracing requirement.

The same gas water heater is installed in that garage on a concrete slab. What is the minimum height that the source of ignition must be elevated above the garage floor?

• a.18 inches✓
• b.24 inches
• c.12 inches
• d.6 inches

Ignition sources in a garage must be at least 18 inches above the floor because gasoline vapors are heavier than air and pool at floor level. 12 inches and 6 inches leave the burner inside the vapor layer. 24 inches is higher than required and is not the code figure, although a taller platform would still comply.

A 120,000 Btu/h gas water heater draws all of its combustion air directly from outdoors through two vertical ducts. Using the 1 square inch per 4,000 Btu/h rule for vertical ducts, what is the required free area of each opening?

• a.15 square inches
• b.12 square inches
• c.30 square inches✓
• d.60 square inches

Dividing 120,000 by 4,000 gives 30 square inches, and that is the required free area for each of the two openings, one near the top and one near the bottom of the enclosure. 60 square inches is the combined area of both openings, not the size of each. 15 square inches halves the correct figure, and 12 square inches corresponds to no recognized ratio.

A 100,000 Btu/h water heater is placed in a closet and will take combustion air from inside the building only. Using the rule of thumb of 50 cubic feet of room volume per 1,000 Btu/h, what minimum volume of communicating space is needed?

• a.10,000 cubic feet
• b.3,000 cubic feet
• c.5,000 cubic feet✓
• d.2,000 cubic feet

Dividing 100,000 by 1,000 gives 100, and 100 times 50 cubic feet equals 5,000 cubic feet of communicating volume. 2,000 and 3,000 cubic feet come from applying a 20 or 30 cubic foot factor that the standard indoor air method does not use. 10,000 cubic feet doubles the requirement and would only be relevant if two such appliances shared the space.

Where an enclosure takes combustion air from an adjacent room through two permanent openings, where must those openings be located?

• a.One opening at the ceiling and one located at any convenient height on an outside wall of the room
• b.Both within 12 inches of the ceiling of the enclosure
• c.One within 12 inches of the top of the enclosure and one within 12 inches of the bottom✓
• d.Both within 12 inches of the floor of the enclosure

The two-opening method requires one opening within 12 inches of the top and one within 12 inches of the bottom of the enclosure so that heated air can exhaust high while replacement air enters low. Placing both openings high or both low defeats the convective loop that drives the air exchange. Locating the lower opening at any convenient height does not satisfy the 12 inch dimension.

A shower compartment is framed 32 inches by 32 inches inside the finished walls. Does it meet the minimum area and minimum dimension requirements for a shower?

• a.No, the minimum interior dimension is 36 inches in every direction
• b.Yes, 1,024 square inches meets the area minimum and 32 inches exceeds the 30 inch dimension minimum✓
• c.No, the area works out to 1,024 square inches but a minimum of 1,200 square inches is required for a stall
• d.Yes, but only if a 30 inch wide door is installed

32 times 32 equals 1,024 square inches and each interior dimension of 32 inches clears the 30 inch minimum, so the stall complies. Code divergence: the UPC (§411.7) sets the minimum area at 1,024 square inches, which 32 by 32 meets exactly, while the IPC (§417.4) sets it lower at 900 square inches, so 1,024 clears both codes. The 1,200 square inch figure and a universal 36 inch interior dimension are not code minimums, and a shower door need only provide a 22 inch clear opening, so a 30 inch door is not what makes the stall compliant.UPC §411.7 / IPC §417.4

An indirect waste pipe from a commercial ice machine is 1-1/2 inches in diameter and discharges into a floor sink. What is the minimum required air gap?

• a.2 inches
• b.1 inch
• c.1-1/2 inches
• d.3 inches✓

The air gap for an indirect waste must be at least twice the effective diameter of the discharge pipe, so 2 times 1-1/2 inches equals 3 inches measured from the pipe outlet to the flood level rim of the receptor. 1 inch is only the absolute minimum air gap for very small pipes. 2 inches and 1-1/2 inches apply the wrong multiplier to the pipe size.IPC §802.2

A 3/8 inch indirect waste tube from a beverage dispenser discharges over an open receptor. Applying the air gap rule, what is the required air gap?

• a.3/8 inch
• b.3/4 inch
• c.1-1/2 inches
• d.1 inch✓

Twice the pipe diameter would be only 3/4 inch, but the code also sets an absolute floor of 1 inch, so the required air gap is 1 inch. The 3/4 inch answer applies the multiplier and ignores the minimum. 1-1/2 inches and 3/8 inch are not produced by either part of the rule.IPC §802.2

A laundry standpipe for a residential clothes washer is roughed in with the top of the standpipe 14 inches above the trap weir. Is the installation acceptable?

• a.Yes, any height is acceptable as long as the trap is vented
• b.No, the standpipe must be at least 24 inches and not more than 60 inches above the trap weir
• c.Yes, 14 inches is within the allowable range
• d.No, the standpipe must extend at least 18 inches and not more than 42 inches above the trap weir✓

A clothes-washer standpipe must be a minimum of 18 inches above the trap weir, so 14 inches is too short and the discharge is likely to back out of the pipe. Height is regulated regardless of venting, so the first choice is wrong. Code divergence is on the maximum: the IPC (§802.4) allows up to 42 inches while the UPC (§807.4) caps it at 30 inches; the 18 inch minimum is common to both codes, which is why 14 inches fails under either code. The 24 to 60 inch range in the second choice is not a code window under either code.IPC §802.4 / UPC §807.4

A showerhead is rated at the maximum allowable flow. A user showers for 8 minutes. Assuming the head flows at its rated maximum, how much water is used?

• a.12.0 gallons
• b.24.0 gallons
• c.17.6 gallons
• d.20.0 gallons✓

The maximum showerhead flow rate is 2.5 gpm at 80 psi, and 2.5 times 8 minutes equals 20 gallons. 17.6 gallons would result from a 2.2 gpm lavatory faucet rate, which does not apply to showerheads. 12 gallons uses a 1.5 gpm rate and 24 gallons uses 3.0 gpm, neither of which is the code maximum for a shower.IPC §604.4

A public restroom is fitted with metering faucets. What is the maximum volume of water each faucet may deliver per metering cycle?

• a.0.25 gallon✓
• b.1.0 gallon
• c.0.5 gallon
• d.0.125 gallon

Public metering faucets are limited to 0.25 gallon per metering cycle, which is a volume limit rather than a flow rate limit because the valve shuts itself off. 0.5 gallon and 1.0 gallon are urinal flush volumes, not faucet cycle volumes. 0.125 gallon is half the allowance and is not a code figure.

A closet flange is set on a wood subfloor before the finished tile is installed, and the installer plans to seal the closet to the flange. Which practice is correct?

• a.Seal the flange to the bowl with structural construction adhesive instead of using any mechanical fasteners at all, then set the bowl
• b.Rely on the closet bolts alone to hold the flange to the floor
• c.Set the flange on top of the finished floor, secure it to the structure with fasteners, and seal with a wax or approved gasket✓
• d.Set the flange below the finished floor and shim the bowl with wood blocks

The closet flange must rest on and be mechanically secured to the finished floor or structure, and the joint between the bowl horn and the flange is sealed with a wax ring or an approved elastomeric gasket. A flange set below the finished floor leaves a gap that the seal cannot reliably bridge, and shimming with wood blocks is not an approved support method. Adhesive does not replace fasteners, and closet bolts secure the fixture to the flange rather than the flange to the floor.

A restaurant installs a grease interceptor sized for 30 minutes of retention. If the connected fixtures produce a peak flow of 25 gallons per minute through the flow control device, what liquid capacity does the retention rule call for?

• a.250 gallons
• b.750 gallons✓
• c.1,500 gallons
• d.500 gallons

Retention volume equals flow rate times retention time, so 25 gpm times 30 minutes equals 750 gallons. 250 gallons corresponds to only 10 minutes of retention and 500 gallons to 20 minutes, both short of the design basis stated in the question. 1,500 gallons would represent a full hour of retention, twice what was specified.

A grease interceptor is inspected and found to contain accumulated grease and settled solids filling 25 percent of the total liquid depth. What action does the common maintenance standard require?

• a.Install a larger flow control device on the inlet to slow the incoming wash-water flow rate
• b.Pump and clean the interceptor, since the 25 percent threshold has been reached✓
• c.No action; cleaning is required only at 50 percent
• d.Add an enzyme treatment and re-inspect in six months

The widely used 25 percent rule requires that an interceptor be pumped when grease and solids occupy a quarter of the liquid depth, because beyond that point retention efficiency falls off sharply. Waiting for 50 percent allows grease carryover into the building drain. Enzyme or chemical treatments emulsify grease so it passes through the unit rather than being retained, and changing the flow control does not remove the accumulated material.IPC §1003.3

A residence has a pressure reducing valve with a check on the incoming water service, and the 40 gallon water heater's relief valve has begun weeping each evening. What is the most likely cause and the correct correction?

• a.The heater is oversized; reduce the thermostat to 90 degrees F
• b.The discharge line is too long; shorten it and add a threaded cap
• c.The relief valve is set too high; replace it with a 250 degree F valve
• d.Thermal expansion in a closed system; install an expansion tank sized for the system✓

A check or pressure reducing valve makes the system closed, so water expanding as it heats has nowhere to go and pressure rises until the relief valve lifts, which is corrected with a properly sized thermal expansion tank. Replacing the relief valve with a higher setting defeats the safety device rather than solving the pressure problem. Lowering the thermostat to 90 degrees F creates a bacterial growth risk, and capping the discharge line is expressly prohibited.

A three compartment pot sink and a food prep sink are being connected in a commercial kitchen. How must the waste from food handling equipment such as a food prep sink be connected to the drainage system?

• a.Directly connected but only through a grease interceptor
• b.Directly connected through a P-trap with no air gap or air break
• c.Indirectly connected through an air gap to an approved receptor✓
• d.Indirectly connected through an air break, which is acceptable for all food equipment

Waste from equipment in which food is stored, prepared, or handled must be indirectly connected by means of an air gap so that sewage cannot back up into food contact surfaces. A direct connection provides no physical break at all, even when a trap or interceptor is present. An air break relies on the pipe extending below the flood rim and is permitted for some indirect wastes but not for food handling equipment.IPC §802.1

A vehicle repair garage has floor drains that may receive oil and flammable liquids. Before that drainage enters the sanitary system it must pass through:

• a.A hydromechanical grease interceptor sized for the fixtures
• b.A standard P-trap on each floor drain and nothing more
• c.A backwater valve set in the garage floor-drain line
• d.An oil (oil-and-sand) interceptor or separator✓

Drainage that can carry oil, gasoline or other flammable and volatile liquids must pass through an oil (oil-and-sand) interceptor so those liquids are separated out and kept out of the sewer, where they are a fire and pollution hazard. A grease interceptor is for animal and vegetable fats from kitchens, a plain P-trap and a backwater valve provide no separation of the oil at all.IPC §1003.4 / UPC §1017

Which discharge is prohibited from passing through a hydromechanical grease interceptor?

• a.A commercial three-compartment pot-and-pan wash sink
• b.A commercial pre-rinse sink ahead of the dishmachine
• c.A food-waste grinder (disposer) and water-closet waste✓
• d.A wok-range scupper drain in the cook line

A hydromechanical grease interceptor is sized for grease-laden wash water, and food-waste grinder discharge and any water-closet (sanitary) waste are prohibited from it: ground food overwhelms and blinds the unit, and sewage has no business in a grease device. Pot sinks, pre-rinse sinks and wok drains are exactly the grease-bearing fixtures the interceptor is meant to serve.IPC §1003.3.1 / UPC §1014

A bathtub-shower combination must be provided with what device to guard bathers against scalding?

• a.A vacuum breaker mounted on the showerhead outlet arm
• b.A pressure-balancing or thermostatic mixing valve limited to about 120 degrees F✓
• c.A check valve installed on the hot-water supply to the valve body
• d.A simple two-handle mixing faucet that provides no maximum outlet temperature stop whatsoever

Tub-shower valves must be pressure-balancing, thermostatic, or a combination type set to a maximum outlet of about 120 degrees F, so a sudden pressure change elsewhere cannot send scalding water to the bather. A vacuum breaker addresses backflow, a check valve addresses cross-flow, and a plain two-handle mixer offers no scald protection at all.IPC §424.3 / UPC §408

Hot water supplied to a public hand-washing lavatory must be limited (tempered) to a maximum temperature of:

• a.140 degrees F
• b.120 degrees F
• c.90 degrees F
• d.110 degrees F✓

Public lavatory hot water must be tempered to a maximum of 110 degrees F, typically with a listed tempering (mixing) valve, to prevent scalding of users who cannot control the supply. 140 degrees is a common storage temperature at the heater, 120 degrees is the tub-shower outlet limit, and 90 degrees is low enough to encourage bacterial growth and is not the code figure.IPC §416.5 / §607

Under the maximum water-use limits adopted by the model codes, the maximum flush volume for a wall-hung urinal is:

• a.0.5 gpf✓
• b.1.0 gpf
• c.1.6 gpf
• d.3.5 gpf

A urinal is limited to 0.5 gallon per flush. 1.6 gpf is the maximum for a water closet, 1.0 gpf describes older urinals no longer permitted new, and 3.5 gpf is a pre-1994 water-closet volume that the water-conservation limits eliminated.IPC §604.4 (EPAct)

A residential dishwasher drain must be protected against backflow of drain water by:

• a.A spring check valve concealed inside the sink base cabinet
• b.A direct low connection to the trap arm underneath the sink
• c.An approved air-gap fitting, or a high loop where the code allows it✓
• d.A grease interceptor placed on the dishwasher drain line

The dishwasher drain must have an approved air-gap fitting, or a high loop where the adopted code permits it, so that a sink stoppage cannot back dirty water into the dishwasher; note the UPC specifically requires an air-gap device, so confirm the local code. A concealed check valve is not an approved method, a direct low connection allows back-flooding, and a grease interceptor is unrelated to this backflow path.IPC §409.2 / UPC §807.4

A storage water heater's combination temperature and pressure relief valve is typically rated to open at about:

• a.210 degrees F / 150 psi✓
• b.180 degrees F / 75 psi
• c.250 degrees F / 300 psi
• d.140 degrees F / 50 psi

A standard residential T and P relief valve is rated to relieve at 210 degrees F and 150 psi, protecting the tank from both overheating and overpressure (IPC 504.4). The other settings do not match the listed valve ratings.

The discharge pipe from a water heater's temperature and pressure relief valve must be:

• a.Fitted with a service shutoff valve
• b.Directed upward
• c.The full size of the valve outlet, draining by gravity, with no valve in the line✓
• d.Reduced to 1/2 in copper for a neater appearance and terminated well above the floor

The T and P discharge pipe must be full size of the valve outlet, drain by gravity, contain no valves, and terminate 6 to 24 in above an approved location with no threads on the end (IPC 504.6). Reducing it, valving it, or running it upward is prohibited.

A storage water heater must be equipped with:

• a.No drain valve
• b.A check valve on the outlet
• c.A drain valve at its lowest point✓
• d.Only a vacuum relief valve

A storage water heater must have a drain valve at its lowest point so the tank can be flushed and drained for service (IPC 504.3). A vacuum relief valve is required only on bottom-fed tanks and does not replace the drain.

A 100,000 Btu/h water heater draws combustion air from outdoors through two horizontal ducts. Using 1 square inch per 2,000 Btu/h for horizontal ducts, what free area must each opening have?

• a.100 square inches
• b.25 square inches
• c.50 square inches✓
• d.12-1/2 square inches

100,000 / 2,000 = 50 square inches for each of the two openings. The vertical-duct method uses 1 square inch per 4,000 Btu/h; using that gives 25, which understates the horizontal-duct requirement.

Using the single-opening (one permanent opening) method that communicates directly with the outdoors at 1 square inch per 1,000 Btu/h, what free area is required for a 120,000 Btu/h appliance?

• a.60 square inches
• b.30 square inches
• c.120 square inches✓
• d.240 square inches

120,000 / 1,000 = 120 square inches, and the single opening must also be at least the sum of the appliance connectors (minimum 100 square inches typically). 30 and 60 apply the 4,000 or 2,000 ratios used for two-opening methods.

A listed flammable-vapor-ignition-resistant (FVIR) gas water heater is installed in a residential garage. What does its listing allow?

• a.It must still be elevated 18 in in all cases
• b.It may be installed at floor level, because it resists igniting flammable vapors✓
• c.It requires no venting
• d.It is prohibited in garages

An FVIR water heater has a flame-arrestor design listed to resist igniting flammable vapors, so it may be installed at floor level in a garage where an ordinary heater would need its ignition source 18 in above the floor. It still must be vented normally.

A single-wall metal vent connector on a gas water heater must maintain what minimum clearance to combustible material?

• a.18 in
• b.6 in✓
• c.12 in
• d.1 in

A single-wall metal vent connector must be kept at least 6 in from combustibles (IFGC / NFPA 54). 1 in is unsafe, and 12 in or 18 in is more clearance than the connector requires (double-wall connectors allow less).

A water heater is set in an attic where a leak could damage the building, so a drain pan is installed. The pan itself must be at least how deep?

• a.1/2 in deep
• b.1-1/2 in deep✓
• c.12 in deep
• d.6 in deep

A water-heater drain pan must be at least 1-1/2 in deep and piped with a minimum 3/4 in indirect drain to an approved point (UPC 507.5 / IPC 504.7). 1/2 in is too shallow to hold a leak, and 6 or 12 in is deeper than required.

At a two-handle fixture fitting, which side is the hot water on as the user faces the fixture?

• a.The bottom
• b.The right
• c.Either side
• d.The left✓

By long-standing convention and code, hot water is supplied on the left and cold on the right at a fitting (IPC 607.1), so users can predict which handle delivers hot water. Reversing them is a scald hazard, and the arrangement is not optional.

What is the maximum flush volume permitted for a water closet under the model-code water-use limits?

• a.1.0 gpf
• b.1.6 gpf✓
• c.3.5 gpf
• d.1.28 gpf

The maximum is 1.6 gallons per flush (IPC 604.4 / EPAct). 1.28 gpf is a high-efficiency level below the maximum, 3.5 gpf is a pre-1994 volume no longer permitted, and 1.0 gpf is a urinal-range value.

What is the maximum flow rate for a residential lavatory faucet at 60 psi?

• a.2.2 gpm✓
• b.0.5 gpm
• c.1.5 gpm
• d.2.5 gpm

A residential lavatory faucet is limited to 2.2 gpm at 60 psi (IPC 604.4). 2.5 gpm is the showerhead limit at 80 psi, and 0.5 gpm applies to public metering/lavatory faucets, not a residential faucet.

What is the maximum flow rate for a public lavatory faucet (other than metering)?

• a.0.5 gpm✓
• b.0.25 gpm
• c.2.2 gpm
• d.2.5 gpm

A public lavatory faucet is limited to 0.5 gpm (IPC 604.4). 0.25 gallon is the per-cycle limit for a metering faucet (a volume, not a flow rate), 2.2 gpm is the residential lavatory limit, and 2.5 gpm is the showerhead limit.

How must the floors of a commercial kitchen with food-prep and wash areas be arranged for drainage?

• a.No drains are needed
• b.The floors are graded to floor drains or floor sinks✓
• c.Carpet is acceptable
• d.Provided with floor drains only in the attached restrooms, not on the cook line

Commercial kitchen floors must be sloped to floor drains or floor sinks so wash-down and spillage drain away, keeping the surface sanitary. Omitting drains or using carpet is not acceptable in a food-service wet area.

A hydromechanical (point-of-use) grease interceptor requires what on its inlet side?

• a.A food grinder discharging into it
• b.A flow-control fitting with an air (vent) intake ahead of it✓
• c.A connection downstream of a water closet
• d.No flow control

A hydromechanical grease interceptor must have a flow-control fitting with an air intake so influent is limited to the rated flow and grease can separate (IPC 1003.3.1). A disposer or water-closet waste is prohibited from a grease interceptor.

A large gravity grease interceptor for a restaurant is usually located:

• a.Outdoors, underground, with manhole access✓
• b.In the attic
• c.Inside the walk-in cooler
• d.Directly under the kitchen sink where it is easiest to reach

A large gravity grease interceptor is a buried tank located outdoors with manhole access so it can be pumped, sized for many minutes of retention. A small hydromechanical unit is the type placed under a sink; the other locations are not serviceable.

A commercial laundry with washing machines must discharge through what interceptor to protect the drainage system?

• a.A lint interceptor or trap✓
• b.No interceptor
• c.A grease interceptor sized for the washing machines
• d.An oil interceptor

Commercial laundry waste carries lint and string that clog drains, so it must pass through a lint interceptor with a removable screen (IPC 1003.6). A grease or oil interceptor targets different contaminants.

A facility that discharges sand and grit, such as a car wash, must drain through:

• a.No interceptor
• b.A lint trap
• c.A grease interceptor ahead of the connection
• d.A sand or solids interceptor✓

Sand and heavy solids must settle out in a sand/solids interceptor before the water enters the sewer (IPC 1003.7). A grease or lint device is designed for fats or fibers, not grit, and would not capture settling solids.

What is the minimum supply pipe size for a flush-tank water closet?

• a.3/8 in✓
• b.1/2 in
• c.1 in
• d.1/4 in

A flush-tank water closet requires a minimum 3/8 in supply (IPC Table 604.5), since the tank refills slowly between flushes. A flushometer water closet, by contrast, needs a 1 in supply for its high instantaneous draw.

What is the minimum supply pipe size for a bathtub?

• a.1/2 in✓
• b.3/8 in
• c.1 in
• d.3/4 in

A bathtub requires a minimum 1/2 in supply (IPC Table 604.5). 3/8 in serves a water-closet tank or lavatory, and 3/4 in or 1 in is larger than a tub requires.

What is the minimum diameter of a residential clothes-washer standpipe?

• a.1-1/2 in
• b.2 in✓
• c.1-1/4 in
• d.3 in

A clothes-washer standpipe must be a minimum of 2 in in diameter to handle the pump's high discharge rate without overflowing (IPC 802.4). 1-1/2 in and 1-1/4 in are undersized, and 3 in exceeds the minimum.

A clothes-washer standpipe trap must be located at what height above the floor?

• a.At the ceiling
• b.48 in above the floor
• c.Below the floor
• d.6 in to 18 in above the floor✓

The standpipe trap must be set between 6 in and 18 in above the floor (IPC 802.4), keeping the seal accessible and at a workable height while the standpipe rises above it. Below the floor or at the ceiling is outside the allowed range.

The floor of a shower compartment must slope to the drain at a minimum of:

• a.1/4 in per ft✓
• b.1/8 in per ft
• c.1 in per ft
• d.1/2 in per ft

A shower floor must slope to the drain at not less than 1/4 in per ft (about 2 percent) so water does not stand (UPC 408.5 / IPC 417.5.2). 1/8 in per ft is too flat and 1/2 in or 1 in per ft is steeper than required and awkward to stand on.

A model-code showerhead is limited to 2.5 gpm at 80 psi. Where several showerheads serve one shower compartment, many codes limit the flow to:

• a.1.5 gpm
• b.2.5 gpm combined for the compartment✓
• c.2.0 gpm
• d.5.0 gpm

The model-code maximum is 2.5 gpm per showerhead at 80 psi, and many adopted codes limit the combined flow of all heads serving one compartment to 2.5 gpm as well, so confirm the adopted code. Treating each head as a separate 2.5 gpm allowance can exceed the limit.

What is the minimum drain size for a commercial food-waste grinder (disposer)?

• a.2 in✓
• b.1-1/4 in
• c.1-1/2 in
• d.3 in

A commercial food-waste grinder requires a minimum 2 in drain and trap because of the volume and character of its discharge (IPC 704 / manufacturer listing). 1-1/2 in serves a residential disposer, and 1-1/4 in is far too small.

What is the minimum drain size for a residential food-waste grinder (disposer)?

• a.1-1/2 in✓
• b.3 in
• c.2 in
• d.1-1/4 in

A residential disposer discharges through the kitchen-sink drain and requires a minimum 1-1/2 in drain and trap. 1-1/4 in is the lavatory minimum and is undersized for a disposer, while 2 in is the commercial-grinder minimum.

What is the minimum trap and drain size for a bathtub?

• a.3 in
• b.1-1/4 in
• c.2 in
• d.1-1/2 in✓

A bathtub requires a minimum 1-1/2 in trap and drain (IPC Table 709.1). 1-1/4 in is the lavatory minimum and is undersized for a tub, and 2 in or 3 in exceeds what a tub requires.

An emergency eyewash or drench shower for worker safety must deliver tepid water in what temperature range?

• a.32 to 50 degrees F
• b.About 140 degrees F
• c.110 to 120 degrees F
• d.60 to 100 degrees F✓

Emergency eyewash and shower equipment must deliver tepid flushing fluid, generally 60 to 100 degrees F (ANSI/ISEA Z358.1), so a victim can tolerate a full flush without cold shock or scalding. 110 degrees and above is a scald risk and near-freezing water drives victims off the unit.

A bathtub trap and its waste-and-overflow concealed in a wall or floor must be provided with:

• a.No access, since it is concealed
• b.A wall that is cut open each time service is needed
• c.The overflow opening only
• d.An access panel or other approved access to the trap and waste✓

Concealed slip-joint connections such as a tub waste-and-overflow must remain accessible through an access panel or removable access so the joints can be serviced (IPC 405.8 / 712 access rules). Sealing them permanently behind finished construction is not permitted.

To control Legionella growth, stored hot water in a water heater is generally kept at a minimum of about:

• a.110 degrees F
• b.90 degrees F
• c.180 degrees F
• d.140 degrees F✓

Storing water at about 140 degrees F suppresses Legionella, while the water delivered to fixtures is tempered down (for example to 110 degrees F at public lavatories) with a mixing valve to prevent scalding. 90 and 110 degrees are within the range where the bacteria thrive.

A fuel-fired water heater installed in a bathroom or a bedroom must be:

• a.Any atmospheric-vented type
• b.Prohibited entirely
• c.Limited to an electric water heater only, because no gas-fired unit of any kind may ever be placed in a bedroom or bathroom
• d.A direct-vent or sealed-combustion type, or installed in a sealed enclosure with combustion air from outdoors✓

A fuel-burning water heater in a bedroom or bathroom must be a direct-vent unit or be enclosed in a sealed room that draws combustion air from outdoors, so occupants are not exposed to combustion products in a sleeping or bathing space (IFGC / IRC). An open atmospheric unit is not allowed there.