Journeyman Plumber (UPC/IPC) — All Questions

Before a new potable water line is placed in service, it must be:

• a.Left as installed
• b.Filled with hot water
• c.Pressure tested with air only, then placed directly in service
• d.Disinfected (chlorinated) and flushed✓

New potable water piping must be disinfected with a chlorine solution and then flushed before use to remove contamination introduced during installation (IPC 610.1). A pressure test alone does not sanitize the pipe.

What must be provided on the water service near where it enters the building?

• a.Only a pressure-reducing valve, with no separate shutoff on the service
• b.Only a check valve
• c.No valve at all
• d.An accessible main shutoff valve on the water service✓

A full-open, accessible main shutoff valve is required on the water service so the whole building supply can be isolated (IPC 606.1). A check valve or a pressure-reducing valve serves a different purpose and does not satisfy the main-shutoff requirement.

What does the code require at each individual fixture supply?

• a.A check valve at each fixture
• b.A single shutoff valve at the main, which serves all of the fixtures at once
• c.An accessible shutoff (stop) valve on each fixture supply✓
• d.No shutoffs at fixtures

Each fixture supply must have an accessible individual stop valve so the fixture can be serviced without shutting down the whole building (IPC 606.2 lists where stops are required). A single main shutoff does not meet the individual-fixture requirement.

Why are listed mechanical water-hammer arrestors preferred over plain air chambers?

• a.Air chambers are illegal
• b.There is no difference
• c.Air chambers are cheaper
• d.Plain air chambers waterlog and lose their air cushion over time, while listed arrestors keep their charge✓

A capped-pipe air chamber gradually absorbs its air into the water and waterlogs, losing its cushion, whereas a listed mechanical arrestor keeps a sealed air or gas charge. That reliability is why arrestors are specified for quick-closing valves.

In water-service sizing, how is the pressure lost through the water meter handled?

• a.Ignored
• b.Relevant only for wells
• c.Subtracted from the available pressure before sizing the piping✓
• d.Added to the available pressure, since the meter is said to boost downstream flow

Meter pressure loss at design flow is one of the deductions taken from the static supply pressure, along with elevation, residual, and backflow-device losses, before the remainder is left for pipe friction. Ignoring it oversizes the friction budget and undersizes the pipe.

For water-distribution sizing, the developed length is measured:

• a.Along the actual pipe run to the most remote fixture✓
• b.To the nearest fixture
• c.As only the vertical rise
• d.As the straight-line (as-the-crow-flies) distance to the most remote fixture

Developed length is measured along the centerline of the pipe, following every offset, to the most hydraulically remote fixture, since that path governs friction loss. A straight-line or nearest-fixture measurement understates the run.

What is the generally accepted maximum design velocity for a cold-water distribution line?

• a.5 fps
• b.12 fps
• c.8 fps✓
• d.15 fps

Cold-water lines are commonly designed to a maximum of about 8 fps to limit noise and erosion; hot-water lines are held lower, near 5 fps. 12 fps and 15 fps are well above accepted practice and cause velocity noise and pipe wear.

A common method of disinfecting new potable piping uses a chlorine concentration and contact time of about:

• a.5 ppm for 1 hour
• b.No minimum concentration is specified; a simple flush with clean water is enough
• c.50 ppm held about 24 hours (or 200 ppm for about 3 hours)✓
• d.500 ppm for 10 minutes

A typical disinfection procedure charges the system to at least 50 ppm chlorine for about 24 hours, or a stronger 200 ppm for about 3 hours, then flushes and confirms an acceptable residual (IPC 610.1). A brief 5 ppm dose is too weak and short.

What is the minimum supply pipe size for a hose bibb (sillcock)?

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

A hose bibb requires a minimum 1/2 in supply (IPC Table 604.5). 1/4 in and 3/8 in are undersized, and 1 in is far larger than a single sillcock needs.

A water-distribution system is tested with water at not less than its working pressure. For how long must the pressure hold with no drop?

• a.15 minutes✓
• b.1 hour
• c.5 minutes
• d.10 minutes

The water-supply test holds at not less than the working pressure for at least 15 minutes with no loss of pressure (IPC 312.5). Any drop indicates a leak; 5 or 10 minutes is short of the required duration.

A lawn irrigation system injects fertilizer or chemicals into the water. What backflow protection does this high-hazard connection require?

• a.A double check valve assembly on the irrigation branch
• b.A reduced pressure principle assembly✓
• c.An atmospheric vacuum breaker
• d.A pressure vacuum breaker

Chemical injection makes irrigation a high-hazard (health) connection, and where it is under continuous pressure or subject to back-pressure it requires a reduced pressure principle assembly (IPC 608.13.2). A vacuum breaker or double check does not protect a high-hazard, back-pressure connection.

Which materials are commonly used for an underground water service?

• a.CPVC only
• b.Type M copper only
• c.Type K copper or PE plastic✓
• d.Galvanized steel pipe only, because it resists corrosion in soil

Underground water services are commonly Type K copper (the heaviest wall) or polyethylene (PE) plastic, both suited to burial (IPC 605 / UPC 604). Type M is generally restricted to above-ground use, and galvanized steel corrodes in soil.

Which provides the most positive, reliable backflow protection for a cross-connection?

• a.An atmospheric vacuum breaker
• b.A pressure vacuum breaker
• c.An air gap (a physical separation)✓
• d.A double check valve assembly

An air gap is a physical vertical separation of at least twice the supply-opening diameter and cannot fail mechanically, so it is the most reliable backflow protection (IPC 608.15.1). Mechanical assemblies rely on checks and springs that can wear.

Where must a lavatory faucet spout be located relative to the flood level rim of the basin?

• a.At the flood level rim
• b.Below the flood level rim
• c.Above the flood level rim to maintain an air gap✓
• d.Submerged in the basin

The faucet spout must terminate above the flood level rim of the fixture so that if the basin fills and the supply loses pressure, contaminated water cannot be siphoned back through the spout (IPC 608.15.1). A spout at or below the rim creates a submerged-inlet cross-connection.

A flushometer valve must be provided with what backflow protection?

• a.An air gap only
• b.An integral (built-in) vacuum breaker✓
• c.A check valve only
• d.No backflow protection

A flushometer discharges below the rim of the fixture, so it must have an integral vacuum breaker downstream of the valve to prevent back-siphonage of fixture water into the supply (IPC 608.15.4). A plain check valve does not provide this protection.