Nevada C-1G Pipes and Vents for Gas Contractor Examination

Per NFPA 54 2012, the point of delivery for a natural-gas piping system (other than undiluted LP-gas) is which of the following?

• 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 valve inside the building
• DThe inlet of the customer-owned second-stage regulator

The NFPA 54 2012 and UMC 2018 Schedule 40 metallic-pipe sizing tables for natural gas are based on which specific gravity?

• A0.60
• B1.00
• C1.50
• D2.00

Unless a listed outdoor-appliance exception applies, underground fuel-gas piping shall be installed with a minimum cover of which depth?

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

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

Polyethylene (PE) plastic fuel-gas pipe is permitted in which of the following locations?

• 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

An underground nonmetallic fuel-gas pipe shall have a tracer that is not smaller than which of the following?

• 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 NFPA 54 2012 / 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

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

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

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

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

Which appliances are among those for which NFPA 54 / UMC 2018 do not require a sediment trap?

• AFurnaces, boilers, and water heaters
• BIlluminating appliances, ranges, clothes dryers, and outdoor grills
• CUnit heaters and duct furnaces only
• DAny appliance with an electronic ignition

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, 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 NFPA 54 2012 / UMC 2018?

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

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

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

Where outdoor underground PE gas pipe must rise above grade at a building, the preferred listed transition is:

• AA field-threaded steel nipple glued into the PE
• BA listed premanufactured anodeless riser or service-head adapter installed per the manufa…
• CA hose-clamp connection to Type L copper
• DAny PVC Sch 40 elbow

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

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

The undiluted-propane sizing tables in NFPA 54 2012 and 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

For undiluted LP-gas, NFPA 54 treats the point of delivery as:

• AThe outlet of the first-stage pressure regulator (or the outlet of the container service…
• BThe fill valve on the tank
• CThe street-side of the natural-gas meter
• DThe appliance orifice

The NFPA 54 / UMC low-pressure undiluted-propane metallic-pipe table used between a single-stage or 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

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

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

The use of plastic pipe, tubing, and fittings in undiluted LP-gas piping systems shall be in accordance with:

• AThe UPC water-pipe chapter only
• BNFPA 58, in addition to the material and joining rules of NFPA 54 / UMC Chapter 13
• CASTM D 1785 PVC Schedule 40
• DAny PE irrigation tubing

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 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

When a propane sizing table is published in cubic feet per hour rather than thousands of Btu per hour, a 250,000 Btu/h load is converted to cubic feet per hour by dividing by approximately which heating value?

• A1,000 Btu per cubic foot
• B1,500 Btu per cubic foot
• C2,500 Btu per cubic foot
• D3,500 Btu per cubic foot

Using NFPA 54 Table 6.3 (undiluted propane, 11.0 in. w.c. inlet, 0.5 in. w.c. drop, Schedule 40 metallic, capacities in thousands of Btu/h), what is the smallest listed pipe that will carry a 200,000 Btu/h load 50 feet from a second-stage regulator?

• A1/2 inch (122 thousand Btu/h at 50 feet)
• B3/4 inch (255 thousand Btu/h at 50 feet)
• C1 inch is the minimum regardless of load
• D2 inch, because propane always requires the next larger size

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

Undiluted-propane metallic-pipe sizing tables in NFPA 54 / UMC 2018 publish capacity in which unit?

• ACubic feet per hour only, identical to the natural-gas tables
• BThousands of Btu per hour
• CGallons per hour of liquid propane
• DPounds per square inch

A contractor sizes an 11 inch water column propane house line with the natural-gas Schedule 40 table (SG 0.60, 0.5 inch drop) and installs 1/2-inch pipe for a 140,000 Btu/h water heater 40 feet from the second-stage regulator. What is wrong with that approach?

• ANothing; the tables are interchangeable if Btu/h is the same
• BThe natural-gas table overstates propane volumetric capacity because propane is denser; t…
• C1/2-inch pipe is never allowed for water heaters
• DPropane house lines must be 1 inch minimum

An LP water heater is rated 140,000 Btu/h. The developed length from the second-stage regulator (11 in. w.c.) to the heater is 40 feet of Schedule 40 steel. Using the 11.0 in. w.c. / 0.5 in. drop propane table, the smallest adequate pipe is:

• A1/2 inch (137 thousand Btu/h at 40 feet)
• B3/4 inch (287 thousand Btu/h at 40 feet)
• C1-1/4 inch, because all water heaters require it
• DCSST EHD 12, regardless of length

Which statement about LP-gas container appurtenances that affect the building piping is correct?

• AAn excess-flow valve, when provided, is intended to close if a downstream line is sheared…
• BThe container relief valve may be piped into the building combustion-air duct
• CThe service valve may be left buried under the tank dome without access
• DA first-stage regulator vent may terminate in a crawl space

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

A 2 psig propane piping system between a 2-pound service regulator and line-pressure regulators at the appliances is sized from the 2.0 psi / 1.0 psi drop table. Compared with the 11 inch WC table, the same Schedule 40 pipe will carry:

• ALess load, because 2 psi is a lower pressure than 11 inches water column
• BA much larger load; for example 1/2-inch pipe at 50 feet carries 1,120 thousand Btu/h at…
• CExactly the same load, because pipe diameter controls capacity
• DNo load; 2 psi propane is prohibited in buildings

Copper tubing used for undiluted LP-gas shall be which type, and joints shall be made how?

• AType M soft copper with soldered 50/50 joints
• BType K or L (or listed ACR) copper, with brazed joints (filler melting above 1,000 F and…
• CDWV copper with solvent-cemented fittings
• DAny copper, provided it is painted yellow

Because undiluted propane vapor is heavier than air, which installation practice is required?

• ALP appliances and piping in pits, unventilated trenches, or similar low spaces need venti…
• BLP piping may be left open-ended in a basement because the vapor will rise out a high vent
• CCombustion air for LP appliances must be taken only from the attic
• DLP appliances cannot be installed anywhere below grade, even in a normally occupied basem…

A single-stage LP regulator mounted at the container feeds the building at about 11 inches water column. That arrangement is most appropriate when:

• AThe building load is large and the run from tank to building is long, because single-stag…
• BThe installation is a small, short-run system (for example a close-coupled tank serving l…
• CThe indoor piping will operate at 10 psi
• DThe contractor wants to omit the appliance shutoff valves

A first-stage LP regulator delivers 10 psi to 50 feet of Schedule 40 steel serving a 400,000 Btu/h second-stage load. Using the 10.0 psi / 1.0 psi drop propane table (capacity in thousands of Btu/h), the smallest adequate pipe is:

• A1/2 inch (1,390 thousand Btu/h at 50 feet)
• B1 inch, because first-stage pipe cannot be smaller than 1 inch
• C2 inch, matching the indoor second-stage main
• DThe 11 inch WC table must be used instead

Elevated-pressure LP piping (for example 2 psi or 10 psi) inside or on a building shall be:

• ALeft unidentified because only low-pressure pipe is labeled
• BIdentified as gas piping operating at elevated pressure, except that labeling is not requ…
• CPainted red for fire protection
• DSleeved in water PVC wherever it is exposed