Nevada C-38 Gas Equipment Contractor Examination

Under NAC 624.550, which work is inside the Nevada C-38 Gas Equipment classification?

• AInsulation of pipes and ducts only, with no gas connections
• BInstalling piping from an LP or natural-gas supply into a building and the related vents,…
• CInstalling only building gas piping and vents, with no appliance or air-heating equipment
• DAny electrical service work associated with a gas furnace

UMC 2018 Schedule 40 metallic-pipe sizing tables for natural gas are computed for which specific gravity?

• A0.60
• B1.00
• C1.50
• D2.00

For a natural-gas system other than undiluted LP-gas, UMC 2018 treats the point of delivery as:

• AThe utility main in the street
• BThe outlet of the service meter assembly or the outlet of the service regulator, whicheve…
• CThe first appliance shutoff inside the building
• DThe inlet of a customer-owned second-stage regulator

Unless a listed outdoor-appliance exception applies, underground fuel-gas piping shall have a minimum cover of:

• A6 inches below finished grade
• B8 inches below finished grade
• C12 inches below finished grade
• D36 inches below finished grade at frost line only

Polyethylene (PE) plastic fuel-gas pipe is permitted in which location?

• AConcealed in an interior partition chase
• BOutdoors, underground only, with a listed transition (typically an anodeless riser) where…
• CExposed along an exterior building wall
• DInside a mechanical room if it is sleeved in Schedule 40 steel

A yellow-jacket CSST natural-gas piping system installed in a building shall be bonded to the electrical-service grounding electrode system with a jumper not smaller than:

• A14 AWG copper
• B10 AWG copper
• C6 AWG copper or equivalent
• D1/0 AWG copper

Each gas appliance shall have an accessible approved manual shutoff valve in the same room and within what maximum distance of the appliance, installed upstream of any connector?

• A3 feet
• B6 feet
• C10 feet
• D25 feet if the valve is readily accessible

Thread joint compounds used on fuel-gas pipe threads shall be:

• AOrdinary PTFE tape of any color
• BResistant to the action of LP-gas or any other chemical constituents of the gases to be c…
• COil-based pipe dope formulated for potable water only
• DProhibited; dry threads are required

An approved individual underground line serving only an outdoor grill, gas light, or similar outdoor appliance, in a location not subject to physical damage, may be installed with a minimum cover of:

• A4 inches
• B8 inches
• C12 inches with no exception
• D18 inches

An underground nonmetallic fuel-gas pipe shall have a tracer that is not smaller than:

• A14 AWG bare aluminum, laid on top of the backfill
• B18 AWG yellow insulated copper wire, or another approved conductor, installed adjacent to…
• C6 AWG bare copper, bonded to the electrical grounding electrode
• DNo tracer is required if the pipe is PE listed for gas

Which statement about corrosion protection of underground steel fuel-gas piping is correct under UMC 2018?

• AFactory zinc coating (galvanizing) is deemed adequate protection for underground steel ga…
• BZinc coating (galvanizing) shall not be deemed adequate protection for underground gas pi…
• CBare black steel may be buried if the trench is sand-bedded
• DOnly cathodic protection is acceptable; coatings are prohibited

Where a sediment trap is not built into the appliance, it shall be installed in which location?

• AUpstream of the appliance shutoff valve, as close to the meter as practical
• BDownstream of the appliance shutoff valve, as close to the appliance inlet as practical
• CIn the utility service riser below the meter
• DOnly on propane systems; natural-gas appliances do not need sediment traps

Fuel-gas piping shall not be installed in or through which of the following?

• AA ventilated crawl space above grade
• BA clothes chute, chimney, gas vent, circulating-air duct, dumbwaiter, or elevator shaft
• CAn accessible basement
• DA listed piping chase

Portions of a gas piping system installed in concealed locations shall not contain which of the following?

• AWelded or brazed joints
• BUnions, tubing fittings, right-and-left couplings, bushings, compression couplings, or sw…
• CThreaded Schedule 40 steel pipe with threaded couplings
• DCSST fittings listed for concealed use

What is the maximum horizontal support spacing for 1/2-inch steel fuel-gas pipe under UMC 2018?

• A4 feet
• B6 feet
• C10 feet
• DEvery floor level only

All piping installed above ground, outdoors, shall be elevated not less than which height above the ground?

• A1 inch
• B2 inches
• C3-1/2 inches
• D12 inches

Gas piping shall enter and exit a building in which manner?

• AThrough the foundation wall below grade in a sealed sleeve
• BAt a point above grade, with the annular space between the pipe and the wall sealed
• CUnder the footing in a Schedule 40 steel conduit only
• DThrough any opening, provided a fire caulk is used

Where external damage to underground gas pipe or tubing from external forces is likely, the minimum cover shall be increased to:

• A12 inches, with no increase required
• B14 inches
• C18 inches, or the pipe shall be installed in conduit or bridged (shielded)
• D48 inches

A CSST fuel-gas piping system shall be installed in accordance with which of the following?

• AThe same hanger spacing and bending radius as Schedule 40 steel
• BThe terms of its approval, the conditions of listing, the manufacturer's instructions, an…
• CField-flared copper fittings and ordinary pipe dope only
• DAny metallic tubing practice the installer prefers

Which of the following uses of metallic fuel-gas piping is prohibited?

• ABonding CSST to the electrical-service grounding electrode system
• BUsing the gas piping as a grounding electrode
• CSupporting the pipe with metal hangers attached to the building structure
• DConnecting a listed appliance connector downstream of the shutoff valve

For piping other than steel pipe, exposed fuel-gas piping shall be identified by a yellow label marked "Gas" in black letters at intervals not exceeding:

• A2 feet
• B5 feet
• C10 feet
• DIdentification is never required if the pipe is painted yellow

Which statement about workmanship on fuel-gas piping is correct?

• AThe piping may be used to support the appliance if the hanger load is under 50 pounds
• BNo gas piping shall be strained or pinched, and no appliance shall be supported by, or de…
• CKinks in CSST may be left in place if they are wrapped
• DDamaged threads may be recut in place and left in the system

Uncoated threaded or socket-welded joints shall not be used in which of the following?

• AExposed indoor steel piping
• BPiping in contact with soil, or where internal or external crevice corrosion is known to…
• CAbove-grade painted outdoor risers
• DAppliance connectors inside a mechanical room

Plastic fuel-gas pipe shall not be operated at pressures greater than which values?

• A5 psig for natural gas and 5 psig for LP-gas
• B100 psig for natural gas or 30 psig for LP-gas
• C2 psig for either gas
• DThere is no pressure limit on listed PE

The undiluted-propane sizing tables in UMC 2018 are based on which specific gravity?

• A0.60
• B1.00
• C1.50
• D2.50

Compared with air, undiluted propane vapor is:

• ALighter than air and rises when released
• BThe same density as air
• CHeavier than air and can collect in low spaces, pits, and basements
• DNonflammable at room temperature

The UMC 2018 low-pressure undiluted-propane metallic-pipe table used between a second-stage regulator and the appliances is based on which inlet pressure and pressure drop?

• A7.0 inches water column inlet, 0.3 inch water column drop
• B11.0 inches water column inlet, 0.5 inch water column drop
• C2.0 psi inlet, 1.0 psi drop
• D10.0 psi inlet, 1.0 psi drop

Per NFPA 58 2014 6.8.2, which regulator arrangement is required on a new fixed piping system that serves 1/2 psig (about 11 inches water column) appliances?

• AA single-stage regulator at the building, with no first-stage device
• BA two-stage regulator system, an integral two-stage regulator, or a 2 psi regulator system
• CNo regulator, because tank pressure is already 11 inches water column
• DA 10 psi indoor manifold with no second-stage regulator

The first-stage regulator on an LP-gas system shall be located:

• AIndoors in the mechanical room so it cannot freeze
• BOutdoors at the container, with its vent terminating outdoors
• CIn the attic above the second-stage regulator
• DInside a sealed pit under the tank

Per NFPA 58 2014, steel pipe 1-1/4 inch and smaller used for liquid or vapor service shall be which schedule if the joints are threaded?

• ASchedule 10
• BSchedule 40
• CSchedule 80
• DAny schedule if the pipe is galvanized

Per NFPA 58 2014 Table 6.4.1.1, an aboveground ASME container of 250 gallons water capacity shall be not less than which distance from a building and from a line of adjoining property that can be built upon?

• A0 feet
• B10 feet
• C25 feet
• D50 feet

Per NFPA 58 2014 Table 6.4.1.1, an aboveground 1,000-gallon water-capacity ASME tank shall be not less than which distance from a building, unless a listed reduction applies?

• A0 feet
• B10 feet
• C25 feet
• D50 feet

Per NFPA 58 2014 Table 6.4.1.1, an aboveground ASME container of less than 125 gallons water capacity may be installed how far from a building?

• A0 feet (against the building is permitted)
• B10 feet minimum with no exception
• C25 feet minimum
• D50 feet minimum

Per NFPA 58 2014 Table 6.4.1.1, an aboveground 5,000-gallon water-capacity ASME container shall be not less than which distance from a building?

• A10 feet
• B25 feet
• C50 feet
• D100 feet

Per NFPA 58 2014 Table 6.4.1.1, no part of an underground ASME container shall be less than which distance from a building or a line of adjoining property that can be built upon?

• A0 feet
• B10 feet
• C25 feet for every underground tank regardless of size
• D50 feet for every underground tank regardless of size

A two-stage LP-gas regulation system places the first-stage regulator at the container and the second-stage regulator at the building in order to:

• ARaise building pressure to 10 psi so smaller indoor pipe can be used without a second reg…
• BReduce tank pressure to an intermediate pressure (commonly about 10 psi) outdoors, then r…
• CEliminate the need for a sediment trap
• DAllow PE plastic pipe to be run exposed through the living space

An ASME LP-gas container filled by volume shall not be filled past which device, which is typically set to leave about 20 percent vapor space (an 80 percent liquid fill) for thermal expansion?

• AThe pressure-relief valve
• BThe fixed maximum liquid level gauge (outage gauge / spit valve)
• CThe first-stage regulator vent
• DThe excess-flow valve

An LP-gas container pressure-relief valve shall discharge:

• AInto the nearest combustion-air opening so the vapor is diluted
• BVertically upward, outdoors, and not into a building, crawl space, or air intake
• CInto the sanitary sewer through a trap
• DThrough a hose routed to the appliance draft hood

An excess-flow valve on an LP-gas container appurtenance is intended to:

• AClose if a downstream line is sheared and flow exceeds its rating
• BRegulate tank pressure down to 11 inches water column
• CIndicate the 80 percent fill level
• DReplace the container pressure-relief valve

Where liquid LP-gas can be trapped between two shutoff valves, NFPA 58 2014 requires which device?

• AA sediment trap tee
• BA hydrostatic relief valve piped to discharge outdoors
• CA second-stage regulator
• DA dielectric union

Per NFPA 58 2014, a flexible connector used in a fixed LP-gas piping system (other than engine fuel) shall not exceed which overall length?

• A18 inches
• B36 inches
• C60 inches
• D10 feet

Metallic piping or tubing that conveys LP-gas from a storage container shall be provided with which device where the pipe or tube enters a building?

• AA dielectric (insulating) fitting, installed above ground outdoors, to electrically isola…
• BA water-hammer arrestor
• CA 60 psi relief valve piped into the combustion-air opening
• DA union buried at the foundation

Plastic pipe used for undiluted LP-gas shall not be operated at more than which pressure, and where may it be used?

• A5 psig, indoors or outdoors
• B30 psig, outdoors underground only, listed for LP-gas, with listed transitions
• C100 psig, exposed on the building wall
• DUnlimited pressure if the PE is yellow

Piping between an LP-gas first-stage regulator (about 10 psi) and the second-stage regulator shall be sized from which table family?

• AThe natural-gas less-than-2-psi, 0.5 inch water column table
• BThe undiluted-propane 10.0 psi inlet / 1.0 psi drop table intended for first-stage to sec…
• CThe 11.0 inch water column / 0.5 inch drop appliance table
• DAny CSST table printed for 7 inch water column natural gas

Per NFPA 58 2014, LP-gas containers shall not be installed in which of the following locations?

• AOutdoors on a firm noncombustible foundation, with required building clearances
• BUnder a building, or inside a building except where the code expressly permits certain cy…
• CAboveground in a side yard that meets Table 6.4.1.1
• DUnderground with required cover and 10 foot building clearance

Combustible materials, weeds, and long dry grass around an LP-gas container shall be kept not less than which distance from the container, per NFPA 58 2014?

• A3 feet
• B10 feet
• C25 feet
• DNo clearance is required if the tank is painted

A 500-gallon water-capacity ASME tank is filled by volume to the fixed maximum liquid level gauge (80 percent). Using 91,500 Btu per gallon of liquid propane, the stored energy is closest to which value?

• A4.6 million Btu (80 percent of 500 × 11,500)
• B18.3 million Btu (200 gal × 91,500)
• C36.6 million Btu (400 gal × 91,500)
• D45.8 million Btu (500 gal × 91,500, ignoring outage)