CSLB General Building (B) — All Questions

A homeowner hires a plumbing company to replace a water heater and reroute the gas line to it. A journeyman employed by that company will perform the installation. Under a typical adopted plumbing code, who is authorized to apply for and hold the permit?

• a.Any journeyman on the crew, because the journeyman is the person who performs and signs off on the installation
• b.The licensed plumbing contractor responsible for the work, or the owner of a single-family dwelling where the jurisdiction allows an owner-builder exemption✓
• c.The plumbing inspector, who issues the permit and holds it on the owner's behalf until the final approval
• d.No one, because replacing an existing water heater is a like-for-like repair that never requires a permit

A permit is issued to the party who is legally responsible for the work, which is the licensed contractor, and many jurisdictions also allow an owner occupying a single-family home to pull a permit for work on that home. A journeyman performs the work under the contractor's license but is not the permit holder. The inspector enforces the code and approves the work; issuing a permit to himself would defeat that separation. Water heater replacement and any change to gas or water piping is permitted work, while truly minor items such as clearing a stoppage or swapping a faucet are the usual exemptions.IPC §106

Underground drainage piping is installed, and the crew backfills and compacts the trench before the groundwork inspection is called for. What does the code require?

• a.The work is accepted if the plumber photographed the piping and the joints before backfilling
• b.The inspector may simply carry the groundwork over and approve it at the rough-in inspection
• c.A reinspection fee is paid and the buried piping is accepted as installed
• d.The concealed work must be uncovered and exposed for inspection, and the cost of uncovering and restoring it is borne by the permit holder✓

Inspections follow a set sequence, typically groundwork or underground, then rough-in or top-out, then final, and no portion of the work may be covered or concealed until it has been inspected and approved. When work is covered early, the code allows the inspector to require it to be uncovered at the permit holder's expense. Photographs are not a substitute for the inspector's own examination and pressure test. Paying a reinspection fee covers the inspector's return trip; it does not buy approval of work no one has seen.IPC §107

Model plumbing codes are published on a three-year cycle. A state adopts one of those editions with statewide amendments, and a city then adopts the state code with additional local amendments. Which document governs an installation in that city?

• a.The most recent model code edition published, whether or not the jurisdiction has adopted it
• b.The model code as published, because the local amendments only apply to commercial work
• c.The edition adopted by the jurisdiction, as amended, since a model code has no legal force until it is adopted✓
• d.The manufacturer's installation instructions, which always supersede any adopted code

A model code is a template with no legal effect on its own; it becomes enforceable only when a state or local jurisdiction adopts it, usually with amendments that reflect local climate, soil and practice. The locally adopted amended edition therefore controls, and the authority having jurisdiction interprets it, with a board of appeals available to hear disputes over that interpretation. Newer published editions do not apply until adopted, which is why a jurisdiction may still be enforcing an edition several cycles old. Manufacturer instructions must be followed for listed and labeled products but cannot override an adopted code requirement.

A drainage, waste and vent system is being water tested. Which statement describes the test correctly?

• a.All openings are tightly plugged and the system is filled with water to at least a 10 ft head, except for the uppermost 10 ft of the system, and the water level is held for at least 15 minutes with no drop✓
• b.The system is filled to a 5 ft head and held for 5 minutes, and a small drop is acceptable if no leak is visible
• c.Only the piping below the lowest floor must be filled, and the water must stand for 30 minutes
• d.Water is run through each fixture for 15 minutes while the inspector watches the joints for drips

The water test plugs every opening, fills the system so that at least a 10 ft head of water stands on the section being tested, and requires the level to hold for a minimum of 15 minutes with no loss. The uppermost 10 ft of the system is the recognized exception, since there is no way to put a 10 ft head on the highest piping. A 5 ft head for 5 minutes is not a recognized test, and any drop in the water level means a leak, not an allowable tolerance. Running water through fixtures is a flow check, not a pressure test, and would not reveal a weeping joint under head.IPC §312.2

A high-rise DWV system is water tested in sections. The highest joint in the section currently under test is 28 ft above the building drain, and three more floors of piping continue above that section. To what height above the building drain must the test standpipe extend?

• a.28 ft, which is the height of the highest joint in the section under test
• b.30 ft
• c.33 ft
• d.38 ft✓

The test requires at least a 10 ft head of water on the highest point of the section being tested, so the standpipe must rise 10 ft above that point: 28 ft + 10 ft = 38 ft above the building drain. Stopping at 28 ft puts zero head on the top joint of the section, and 30 ft and 33 ft leave only 2 ft and 5 ft of head. The 10 ft exception for the uppermost portion of the system does not apply here because more piping continues above this section.IPC §312.2

Freezing weather makes a water test impractical, so the DWV rough-in is air tested instead. Which combination of test pressure and duration satisfies the code?

• a.3 psi held for 10 minutes
• b.10 psi held for 30 minutes
• c.5 psi, or a mercury column of 10 in, held for at least 15 minutes with no loss of pressure✓
• d.50 psi held for 15 minutes

The DWV air test uses a uniform gauge pressure of 5 psi, or the equivalent 10 in mercury column, maintained for at least 15 minutes without any drop. Three psi is below the required pressure and 10 minutes is short of the required duration. Ten psi and 50 psi are far above what a drainage system is intended to see; 50 psi is the water supply test value, not the DWV value, and that much air can blow test plugs out of a fitting.IPC §312.3

A water distribution system that will operate at 45 psi working pressure is tested with water. The plumber pumps it to 48 psi, and after 15 minutes the gauge reads 46 psi. How should the result be reported?

• a.Pass, because the test pressure of 48 psi exceeded the 45 psi working pressure of the system
• b.Fail, because the test must be at the working pressure but not less than 50 psi and must hold for 15 minutes with no drop✓
• c.Pass, because a 2 psi drop over 15 minutes is within the allowable tolerance for a supply test
• d.Fail, because a water supply system may only be tested with compressed air at 100 psi

The supply test is run at the system's working pressure but never less than 50 psi, and it must hold for at least 15 minutes without a loss of pressure, so a 48 psi start that falls to 46 psi fails on both counts. Exceeding the working pressure alone is not enough when the code sets a 50 psi floor. There is no allowable pressure drop; any drop indicates a leak. Air may be permitted as an alternate test medium in some jurisdictions, but it is not the only method and 100 psi is not the required value.IPC §312.5

On a set of plumbing drawings, which view shows the vertical arrangement of the DWV piping, the floor-to-floor relationships and the order of the connections, drawn at an angle and generally not to scale?

• a.The riser or isometric diagram✓
• b.The floor plan view
• c.The civil or site utility plan
• d.The fixture schedule

A riser or isometric diagram is a single-line pictorial drawing of the system in three dimensions; it shows what connects to what and at what level but is not drawn to scale, so lengths cannot be measured off it. The floor plan is a scaled overhead view used to locate piping horizontally and to read symbols such as CW, HW, waste and vent. The site plan shows the sewer and water service outside the building along with invert elevations and benchmarks. The fixture schedule is a table of fixture types, models and connection sizes, not a view of the piping.

A floor plan is drawn at a scale of 1/4 in = 1 ft. A straight run of cold water piping measures 3-1/2 in on the drawing. What is the actual length of that run?

• a.3 ft 6 in
• b.10 ft 6 in
• c.14 ft✓
• d.17 ft 6 in

At 1/4 in = 1 ft, every full inch on the drawing represents 4 ft, so 3.5 in x 4 ft = 14 ft. Reading 3 ft 6 in simply repeats the measured inches as feet and ignores the scale entirely. Ten feet six inches comes from multiplying by 3 instead of 4, and 17 ft 6 in comes from multiplying by 5. Checking the answer the other way confirms it: 14 ft x 1/4 in per ft = 3.5 in on paper.

A site plan shows the invert elevation of a building sewer as 102.50 ft at the upstream end and 101.90 ft at the downstream end, with 48 ft of run between the two points. What is the slope of the sewer in inches per foot?

• a.0.0125 in per ft
• b.0.10 in per ft
• c.0.125 in per ft
• d.0.15 in per ft✓

The fall is 102.50 - 101.90 = 0.60 ft, which is 0.60 x 12 = 7.2 in, and 7.2 in divided by the 48 ft run gives 0.15 in per ft. The value 0.0125 is the slope expressed in feet per foot, not inches per foot, so it is off by a factor of 12. One tenth of an inch per foot would produce only 4.8 in of fall over 48 ft, and 0.125 in per ft, the familiar 1/8 in per ft grade, would produce 6 in of fall. Both are plausible-looking but leave the pipe higher than the plan calls for at the connection.

A building sewer runs 62 ft from the building drain to the connection at the main and is to be graded at 1/4 in per foot. The invert elevation at the upstream end is 100.00 ft. What is the invert elevation at the downstream end?

• a.98.71 ft✓
• b.98.45 ft
• c.99.35 ft
• d.101.29 ft

Total fall is 62 ft x 1/4 in per ft = 15.5 in, and 15.5 in divided by 12 is 1.29 ft, so the downstream invert is 100.00 - 1.29 = 98.71 ft. The value 98.45 uses 3/8 in per ft or rounds the fall to 18.6 in. The value 99.35 halves the fall, as if the grade were 1/8 in per ft, and 101.29 applies the fall in the wrong direction, which would run the sewer uphill toward the main.

A crew is setting sewer pipe in a trench 5 ft 6 in deep with vertical walls cut in previously disturbed soil. No sloping, shoring or shielding has been installed. What does OSHA require before a worker enters?

• a.Nothing, because a protective system is required only at 6 ft and greater
• b.A warning line at the top of the trench and a spotter watching the walls are sufficient at this depth
• c.A protective system such as sloping, benching, shoring or a trench shield must be in place, because the excavation is 5 ft or more in depth✓
• d.The competent person may waive protection if the trench will be open for less than one work shift

Employees in an excavation 5 ft deep or more must be protected by an adequate protective system, and the only exception is an excavation made entirely in stable rock. The 6 ft figure is a fall-protection threshold, not the trenching trigger. A warning line and a spotter do nothing to stop a wall from collapsing on someone standing in the trench. The competent person can require protection at less than 5 ft when there are signs of a cave-in hazard, but has no authority to waive it based on how long the trench will stay open.29 CFR 1926.652(a)(1)

A trench 7 ft deep with a 3 ft wide bottom is excavated in Type C soil and will be protected by sloping the walls at 1-1/2 to 1. How wide must the excavation be at the top?

• a.13 ft 6 in
• b.24 ft✓
• c.17 ft
• d.10 ft 6 in

Type C soil is sloped 1-1/2 horizontal to 1 vertical, about 34 degrees from horizontal, so each wall lays back 1.5 x 7 = 10.5 ft. Both walls are sloped, giving 3 + 10.5 + 10.5 = 24 ft at the top. The 13 ft 6 in answer adds the layback to only one side, and 10 ft 6 in is the layback of a single wall with the trench bottom left out entirely. Seventeen feet corresponds to a 1 to 1 slope, which is the ratio for Type B soil, not Type C.29 CFR 1926.652(b)

A trench 5 ft deep and 90 ft long is open, with workers spread along its full length installing pipe. What is the minimum number of ladders required and how must they be placed?

• a.Two, placed so that no worker has more than 25 ft of lateral travel to reach a means of egress✓
• b.None, because a ladder is required only in trenches 6 ft deep or greater
• c.One, placed at the midpoint of the trench
• d.Four, one for every 25 ft of trench length

Trenches 4 ft deep or more need a stairway, ladder, ramp or other safe means of exit located so that a worker travels no more than 25 ft laterally to reach it, so each ladder serves 25 ft in each direction, or 50 ft of trench. Ninety feet therefore needs two ladders, positioned so their 50 ft zones overlap and cover the whole length. The depth trigger is 4 ft, not 6 ft, so doing nothing is a violation. A single ladder at the midpoint leaves workers at the ends 45 ft from egress, and four ladders exceeds what the rule requires.29 CFR 1926.651(c)(2)

A trench must be excavated 22 ft deep in Type B soil to reach an existing sewer main. Which statement about the protective system and the excavated material is correct?

• a.The standard sloping tables may be used at any depth, and the spoil may be piled at the trench edge to serve as a barrier
• b.Sloping is prohibited over 20 ft so only a trench box may be used, and the spoil must be kept 1 ft back
• c.The competent person may design the protective system on site at this depth, and the spoil must be kept 5 ft back
• d.A protective system for an excavation deeper than 20 ft must be designed by a registered professional engineer, and excavated material must be set back at least 2 ft from the edge✓

The tabulated sloping, benching and shoring options in the standard stop at 20 ft; anything deeper requires a protective system designed by a registered professional engineer. Spoil, tools and other surcharge loads must be kept at least 2 ft from the edge, or retained by a device that prevents material from falling in. Piling spoil at the edge adds load to the very wall that is most likely to fail, so it is never a barrier. A competent person inspects the excavation daily, before each shift and after rainstorms, but cannot substitute his own judgment for the engineered design a 22 ft trench requires.

Before anyone enters a 12 ft deep sewer manhole classified as a permit-required confined space, the atmosphere is tested and the meter reads 19.2 percent oxygen. What is the correct interpretation, and in what order must the atmosphere be tested?

• a.The reading is acceptable, and the correct order is toxics first, then oxygen, then flammables
• b.The reading indicates an oxygen-enriched atmosphere, and the correct order is flammables first, then oxygen, then toxics
• c.The reading is oxygen deficient, and the space must be tested for oxygen first, then flammable gases and vapors, then toxic contaminants✓
• d.The reading is acceptable as long as the entrant wears a filtering facepiece respirator and an attendant is posted

An acceptable atmosphere holds oxygen between 19.5 and 23.5 percent, so 19.2 percent is oxygen deficient and entry is prohibited until the space is ventilated and retested. Testing follows a fixed order of oxygen, then flammables, then toxics, because combustible gas sensors need oxygen to give a valid reading and a low oxygen result makes the flammability reading unreliable. An enriched atmosphere is above 23.5 percent, not below 19.5. A filtering facepiece only removes contaminants from the air; it cannot add oxygen, so it is never permitted in an oxygen-deficient space, which requires supplied air along with an attendant, a signed entry permit and a retrieval system.29 CFR 1910.146

A plumber is brazing copper joints in a finished mechanical room with combustible wood framing a few feet away. Which practice meets the fire prevention requirements for the work?

• a.The acetylene regulator may be set to 20 psig to speed up the braze as long as the cylinder is chained upright
• b.A fire extinguisher is kept at the work area and a fire watch is maintained for at least 30 minutes after the torch is shut off✓
• c.A fire watch is required only for welding, since brazing and soldering do not produce enough heat to start a fire
• d.Cylinders may be laid on their side while in use provided they are blocked so they cannot roll

Hot work requires suitable fire extinguishing equipment kept ready at the site and a fire watch maintained for at least 30 minutes after the work stops, because smoldering combustibles behind a wall or above a ceiling can take that long to flare up. Acetylene is unstable at pressure and must never be used above 15 psig at the torch. Brazing and soldering both use an open flame and easily ignite framing, insulation and dust, so the fire watch applies to them as well. Cylinders are stored, transported and used upright and secured so the valve cannot be broken off and the acetone in an acetylene cylinder is not drawn into the hose.29 CFR 1926.352

While replacing a section of galvanized water piping in a building from the 1950s, a plumber finds an adjacent steam line wrapped in crumbling fibrous insulation and sees that the old water joints were made with 50/50 tin-lead solder. What is the correct response?

• a.Cut the insulation off with a utility knife, bag it, and continue with the repair
• b.Wet the insulation before removing it, since wetting eliminates the need for a licensed abatement contractor
• c.Disturb the insulation only while wearing a filtering facepiece, and reuse 50/50 solder so the new joints match the existing system
• d.Leave the suspect asbestos insulation undisturbed, stop work in that area and notify the employer or building owner so a licensed abatement contractor can assess it, and make the new joints with lead-free solder✓

Deteriorating pipe insulation in a building of that era is presumed asbestos-containing until sampling proves otherwise, and the correct action is to leave it alone, keep others out of the area and report it so licensed abatement personnel handle the removal. Cutting, scraping or wetting it yourself still releases fibers and does not make an untrained worker an abatement contractor, and a filtering facepiece does not authorize the work either. On the piping side, 50/50 tin-lead solder is prohibited in potable water systems; solder and flux must be lead free, and wetted surfaces of pipe, fittings and fixtures must not exceed a weighted average lead content of 0.25 percent.