Nevada A-20 Industrial Piping Contractor Examination

Before opening a steam or chemical process line for repair, the Nevada A-20 crew's first safety control is to:

• AIsolate the line, relieve stored energy, and apply lockout/tagout
• BIncrease system pressure so residual fluid is forced out of the joint
• CCrack the nearest flange while the line is still at operating pressure
• DPurge the line with pure oxygen to clear residual product

Which medium is prohibited for pressure-testing industrial piping?

• AOxygen
• BDry nitrogen
• CClean water
• DCompressed air on metallic pipe

A fitter grinding a carbon-steel steam weld should wear, at minimum:

• AA cloth dust mask and ordinary eyeglasses
• BOnly leather gloves, because sparks stay below eye level
• CSafety glasses with side shields or a face shield plus hearing protection as needed
• DA welding helmet with no filter lens

A vault or tank pit used to install industrial piping is treated as a confined space primarily because it:

• AHas limited entry and may contain a hazardous atmosphere
• BAlways contains potable water
• CIs shallower than 12 inches
• DIs painted safety yellow

Welding on an in-place industrial piping system normally requires a hot-work permit so that:

• ACombustibles, flammable atmospheres, and fire watch are controlled before the arc is stru…
• BThe welder can skip fire watch if the pipe is wet
• CThe building fire alarm can be permanently disabled
• DOxygen can be used to accelerate the weld

On an industrial piping site, a hard hat is required mainly to protect against:

• AStruck-by hazards from pipe, fittings, and overhead loads
• BSunburn only
• CHearing loss from steam leaks
• DChemical absorption through the scalp

Under OSHA lockout/tagout, an authorized employee is the person who:

• AOnly observes the work from outside the barricade
• BHolds the plant keys but has no isolation training
• CPerforms the lockout and is trained to isolate that energy source
• DRemoves any lock that is slowing production

During a pneumatic pressure test of a large-diameter industrial line, the safest practice is to:

• ABarricade the test area, raise pressure in steps, and keep personnel clear of joints
• BStand at the blinded end to listen for leaks
• CUse the highest available compressor setting to shorten the test
• DLeave all vents and drains open so pressure cannot build

Before selecting gasket, valve, and pipe materials for a chemical service, the A-20 contractor should first consult:

• AThe safety data sheet and the owner's material compatibility specification
• BThe paint color of the existing plant piping
• CA residential plumbing fixture catalog
• DOnly the pump nameplate voltage

An atmosphere is oxygen-deficient, and entry is unsafe without additional controls, when oxygen falls below:

• A23.5 percent
• B21.0 percent
• C19.5 percent
• D16.0 percent only if the space is also hot

Before cutting into an existing steam main, the crew must verify that:

• ABlock valves are closed, drains are open, and the line is depressured and cool enough to…
• BThe trap discharge is lukewarm, which proves the main is empty
• CThe boiler is at high fire so condensate is driven out
• DA check valve somewhere downstream will hold the steam

Compressed-gas cylinders used for welding or nitrogen testing must be:

• ASecured upright with caps on when not in use, and oxygen separated from fuel gas
• BStored on their sides so regulators cannot be damaged
• CChained to the hot-work area with regulators left under pressure overnight
• DPlaced inside the excavation to keep them cool

Hearing protection is required on an industrial piping job when:

• ANoise reaches OSHA action or permissible exposure levels, such as loud grinding, steam bl…
• BThe worker prefers music over steam noise
• CThe pipe is smaller than 2 inches
• DThe work is outdoors, because outdoor sound is never regulated

After hot work on insulated industrial piping, a fire watch should continue because:

• AThe building department requires a 24-hour structural inspection
• BWelding rods remain explosive until they cool to room temperature
• CSlag can smolder inside insulation or in cracks long after the arc stops
• DFire watches replace the need for a fire extinguisher

When arc-welding industrial steel pipe, the work lead (ground) should be connected so that:

• AThe welding circuit is completed on the work piece and does not stray through bearings, c…
• BCurrent travels through stainless instrumentation tubing to protect the weld
• CThe electrode holder is taped to a live steam line
• DThe machine frame is left ungrounded to reduce shock

A permit-required confined space used for industrial piping work must have, before entry:

• ADocumented atmospheric tests, an attendant, rescue provisions, and isolation of hazardous…
• BOnly a flashlight and a cell phone
• CA single worker inside so there is more room to move
• DThe space sealed airtight so no gas can enter during the shift

A 200 psi pneumatic test on a long welded header fails a flange. The stored-energy concern is that:

• AAir at 200 psi stores far more energy than the same volume of water, so fragments travel…
• BAir always leaks slower than water, so the failure is harmless
• CPneumatic tests cannot injure workers if the gauge is calibrated
• DOnly hydrostatic tests create stored energy

For a hazardous chemical line that must be opened, the most complete isolation method is:

• AA single check valve
• BA control valve left in automatic
• CDouble block and bleed, or a blind, after verifying zero energy
• DA tagged-open drain with no block valves

Nevada A-20 Industrial Piping work is limited to fabrication and installation of pipes that carry:

• AOnly potable building water and sanitary waste
• BOnly underground electrical conduit
• CSteam, gases, chemicals, and other industrial or commercial process substances, plus rela…
• DOnly fire-sprinkler branch lines in dwelling units

The most common material for ordinary industrial steam piping is:

• ASchedule 40 or heavier carbon steel
• BUnreinforced flexible PVC hose
• CThin-wall DWV copper
• DPerforated corrugated drain pipe

Corrosive chemical process lines are most often specified in:

• ABlack iron with no lining, regardless of the fluid
• BGalvanized steel because zinc resists every acid
• CStainless steel or another alloy/plastic listed as compatible with the chemical
• DCast-iron soil pipe with lead-oakum joints

Compared with Schedule 40 pipe of the same nominal size, Schedule 80 pipe has:

• AA thicker wall and a smaller inside diameter
• BA thinner wall and a larger inside diameter
• CThe same wall thickness but a different steel grade only
• DNo inside diameter because it is used only as tubing

A butt-welded joint is preferred on larger industrial process lines because it:

• ACreates a full-penetration joint with a smooth bore and high integrity
• BIs the only joint allowed on 1/2-inch instrument tubing
• CNever requires inspection
• DCan be assembled with a pipe wrench and thread sealant

Insulation on industrial steam and hot hydronic piping is installed mainly to:

• AHide leaks from the inspector
• BIncrease the pipe's internal design pressure
• CReduce heat loss and protect people from contact burns
• DEliminate the need for hangers

Per UMC Table 313.3, horizontal steel water or hydronic pipe 1 inch and larger must be supported at intervals not exceeding:

• A4 feet
• B6 feet
• C12 feet
• D25 feet

Per UMC Table 313.3, horizontal copper or copper-alloy pipe 1-1/2 inches and smaller must be supported at least every:

• A32 inches
• B12 feet
• C6 feet
• D15 feet

Per UMC Table 313.3, horizontal 1/2-inch steel gas pipe must be supported at intervals not exceeding:

• A4 feet
• B10 feet
• C12 feet
• D6 feet

Per UMC Table 313.3, horizontal PEX tubing 1 inch and smaller must be supported at least every:

• A32 inches
• B6 feet
• C10 feet
• D12 feet

An expansion loop is installed in a long steam or hot-water run to:

• AAbsorb thermal growth so anchors and joints are not overstressed
• BIncrease pump head by adding friction
• CTrap condensate at the high point
• DReplace the need for any hanger within 40 feet

On a long steam line, a pipe guide is used to:

• ALock the pipe so it cannot move in any direction
• BReplace the expansion joint entirely
• CSupport the full weight of a vertical riser by friction alone
• DAllow axial movement while keeping the pipe aligned into an expansion loop or joint

A dielectric union or isolating flange is installed where copper hydronic pipe joins steel because:

• AThe joint must be electrically bonded to become a grounding electrode
• BCopper cannot be soldered within 10 feet of steel
• CDissimilar metals in water form a galvanic couple that corrodes the steel
• DThe UMC forbids any steel in a hydronic system

Industrial steam, gas, and chemical piping should be identified so that:

• AOnly the original installer can read the markings
• BPaint color can be changed weekly without records
• CWorkers can tell contents, direction of flow, and hazards before opening a valve
• DUnmarked lines are assumed to be air

Buried industrial piping is commonly installed with warning tape and, for nonmetallic pipe, a tracer wire so that:

• AThe pipe can be omitted from the as-built drawing
• BCathodic protection is never required on any steel line
• CThe trench can be backfilled with scrap metal
• DFuture excavators get a visual or electronic warning before striking the line

Socket-weld fittings on industrial piping are typically limited to smaller sizes, often 2 inches and under, because:

• AThe socket creates a small internal crevice that is acceptable on small lines but undesir…
• BSocket welds cannot be made on carbon steel
• CButt welds are illegal below 8 inches
• DA socket weld is only a tack and has no throat

Using α = 6.5 × 10⁻⁶ in/in·°F, how much will 100 feet of carbon-steel pipe expand if the temperature rises 100°F?

• A0.26 inch
• B1.56 inches
• C0.78 inch
• D7.80 inches

A 200-foot carbon-steel steam main is installed at 50°F and operates at 230°F. Using α = 6.5 × 10⁻⁶ in/in·°F, the free thermal expansion is closest to:

• A0.78 inch
• B1.56 inches
• C5.62 inches
• D2.81 inches

Using V = 0.4085 × Q / d², the approximate water velocity in a 2-inch pipe (use d = 2.0 in) carrying 50 gpm is:

• A2.0 feet per second
• B10.2 feet per second
• C5.1 feet per second
• D20.4 feet per second

A long, high-temperature steam line with limited space for a large loop is often fitted with a bellows expansion joint. The joint must be:

• AInstalled without anchors so it can float freely
• BUsed as the only support for the adjacent pipe span
• CGuided and anchored so it takes only the movement it was designed for, and not used as a…
• DFilled with concrete so it cannot flex

A centrifugal pump moves liquid primarily by:

• AA reciprocating piston that traps a fixed volume
• BBoiling the liquid so vapor pressure pushes it forward
• CCompressed air injected into the suction line
• DAn impeller that adds velocity, which a volute converts to pressure

A Y-strainer is installed in industrial piping to:

• AIncrease fluid velocity through the pump
• BServe as the system expansion tank
• CCatch scale and debris before it reaches pumps, traps, or control valves
• DReplace the need for a pressure-relief valve

A shell-and-tube heat exchanger is used on industrial piping jobs to:

• AStore compressed air for pneumatic tools
• BTransfer heat between two fluids without mixing them
• CIncrease pipe schedule by plating metal on the wall
• DMeter electrical power to the boiler

A closed hydronic or hot-water system needs an expansion tank because:

• AThe tank is the only legal location for a circulating pump
• BOpen vents are forbidden on every hydronic system
• CThe tank raises the boiling point of water by adding glycol
• DHeated water expands and the extra volume must be absorbed without lifting the relief val…

An air separator on a hydronic system is installed to:

• AAdd makeup air to the boiler room
• BRemove entrained air so pumps do not bind and corrosion is reduced
• CIncrease the oxygen content of the loop water
• DServe as the pressure-relief device

A steam trap is installed to:

• AHold steam in the heating unit while discharging condensate and air
• BRaise steam pressure above the boiler safety-valve setting
• CMix condensate back into the steam main
• DReplace the boiler low-water cutoff

Cavitation in a centrifugal pump is most often caused by:

• AToo much net positive suction head available (NPSHa)
• BA fully flooded suction with a short, oversized inlet
• CPumping cold water at a very low speed
• DNPSHa falling below the pump's required NPSH, so vapor bubbles form and collapse

To improve NPSHa on a hydronic or process pump, the installer should:

• AAdd many elbows and a small suction reducer right at the pump
• BThrottle the suction valve to quiet the pump
• CKeep the suction short, full-size, and flooded, with the strainer clean
• DMount the pump as high above the liquid source as the room allows