NFPA 54 National Fuel Gas Code Practice Test

These questions are part of the practice quiz. Start practicing

• When using combustion air ducts to supply makeup air, they shall not be screened when terminated in which location?
• What is the indicated pipe pitch for gas piping?
• When changing a gas stove to an exhaust hood, what must be installed and wired to exhaust?
• Which component provides dilution air to the vent system of a gas water heater?
• Btu stands for which term?
• Maximum CSST length on blocks
• A fan-assisted appliance is considered to be what category?
• Which of the following is a factor in gas pipe sizing?
• What is the minimum distance from a cooktop to cabinets?
• Because natural gas is lighter than air, it will do what if released inside a building?
• Where can plastic pipe for gas be used?
• What is the minimum clearance for a single-wall metal flue pipe from combustibles?
• What is the smallest pipe size that can be concealed in a wall?
• Which practice ensures a gas-tight 2 1/2-8 NPT joint in natural gas installations?
• What is the minimum gas piping size for concealed installations?
• What gauge tracer wire is recommended for underground gas installations?
• Gas passing through a gas meter is measured in which units?
• The air duct for combustion must be located how far from the ceiling and floor respectively?
• Consumer owned gas pressure boosters must be what type?
• What is the gas pressure test requirement for existing piping?
• What device must be installed where the gas pressure is higher than the design pressure of the equipment or supply lines?
• Which component provides a positive induced draft in a vented appliance system?
• In the pipe thread designation '2 1/2-8', what does the '8' represent?
• Elevated pressure labeling and color scheme is the same as which system?
• What is the minimum gas piping size for buried installations?
• What is the minimum trench depth for gas installation, and the maximum depth if hazards are present?
• Gas equipment shall not utilize combustion air or ventilation air from which spaces?
• How should CSST installed underground be prepared?
• Emergency shutoff valves for laboratories must be positioned
• What is the smallest size gas piping buried underground?
• What percentage of natural gas is Ethane?
• Where should elevated pressure piping labels be placed?
• What is the required height above the floor for a gas unit heater installed in a commercial garage?
• Railings on roof near units within 6 feet of the edge need a railing which is at least how tall in inches?
• Which appliance category does not create condensate?
• Type 1 clothes dryers can be installed in closets in bedroom or bath only when what is true?
• Gas flex hoses installed in industrial appliances shall not exceed how many feet?
• A double acting barometric damper is used to automatically shut off the fuel to the burner in the event of a fuel gas spillage exceeds how many seconds?
• Which statement accurately describes the dual-fuel labeling colors?
• Labeling for dual fuels should be performed at what interval when there is a change of direction?
• A gas appliance with 60,000 BTU input requires how much combustion air (cubic feet)?
• Gas piping at multiple meter installations must be marked with what?
• Access is required for gas equipment on roofs when the building height exceeds how many feet?
• Which pairing correctly describes the labeling colors for dual fuels? Natural gas and LP.
• Which component is a draft hood that provides dilution air and is placed to connect the appliance vent to the chimney?
• Approximately how many BTUs are in one cubic foot of natural gas?
• In boiler systems, the device used to limit excessive pressure or temperature is called a
• Gaskets used on gas flanges must be full-faced and be made of which materials?
• Gasket materials for gas flanges must be full-faced and be made of which materials?
• Are interior meter connections for CSST allowed?
• A level working platform needs to be provided at service side of appliances on top of roofs at what size?
• The label on elevated pressure piping must indicate which two things?
• Which of the following is the correct minimum size for natural gas piping?
• What is the maximum trench depth allowed when hazards are present?
• The diversity factor is used to size piping for which scenario?
• What does CSST stand for in gas piping?
• Which gas should never be used to test gas piping?
• What is processed air?
• Can plastic gas piping penetrate foundation?
• Gas pressure at the outlet of a natural gas meter is usually measured in inches water column. What value is typical?
• For gas piping systems with an input greater than one million Btu, the test pressure must be at least how many times the working pressure?
• Gas piping systems in excess of 1,000,000 BTU input shall be tested for a maximum of how many hours?
• CSST shall not be connected to which of the following?
• The opening in the atmospheric side of the regulator housing permitting the in and out movement of air to compensate for the movement of the regulator diaphragm
• Leak testing duration is specified per what length of piping?
• Which statement describes the longest length sizing method?
• Gas connectors cannot pass through which components?
• Which term describes air externally supplied to the flame at a point of combustion?
• Combustion air ducts used to supply makeup air must be screened except when terminated in what location?
• What is the gas pressure test requirement for new piping?
• What is the minimum trench depth for gas installation?
• The calculation used to supply makeup air through a wooden louver must be reduced by what percent?
• What is primary air?
• What are the approximate components of natural gas by percentage?
• Which flange material requires full-face gaskets on gas piping flanges?
• When installing single wall metal flue pipe, what is the proper clearance from combustibles construction?
• One inch of mercury is equal to how many psi?
• Gas equipment shall not utilize combustion air from which spaces?
• When a draft hood is used it shall be installed
• Pipe and fittings in excess of 4 inches: what joining method is required?
• Gas piping test pressure is commonly specified in which unit?
• The diversity factor accounts for what in gas piping design?
• Where must drip tees be placed in gas lines?
• What is the maximum gas pressure allowance for CSST installations, expressed as inches of water column?
• Vertical outside air opening requirements specify 1 square inch per 4000 BTU, not less than how many inches?
• Residential gas regulator settings are typically measured in which unit?
• Which statement best describes the relationship between nominal pipe size and actual outside diameter in NPT fittings?
• What is the minimum distance between a gas regulator and any ignition source?
• Which component is used to regulate gas pressure in a gas piping system?
• An adjustable device for varying the size of the air inlet or inlets regulating primary or secondary air would be
• For piping operating greater than 10 psig up to 70 psig, what test pressure is required?
• Penetration of gas pipe through floors, patio or slab must have at least how many inches of unthreaded pipe?
• For a 2 1/2-8 NPT fitting, how many threads are present in one inch of thread length?
• The acronym AWS stands for which organization?
• Outside air for vertical combustion is defined as an opening size of 1 square inch per 4000 BTU, not less than 3 inches.
• What describes the relationship between nominal pipe size and threads per inch in NPT design?
• Which diameter is the minimum piping size for buried natural gas piping?
• Label size for elevated pressure piping must be sized relative to what?
• What type of vent is not approved for gas?
• What is the primary function of a draft hood in a gas-fired appliance vent system?
• Which gas is used as the testing medium in piping tests?
• What are the three sizing methods used for gas piping systems?
• Direct gas-fired industrial air heaters may not be utilized unless the CO concentration discharged is at or below what level?
• Which term describes equipment installed as part of the vent to provide a positive induced draft?
• What is the standard air-to-natural gas ratio for combustion?
• The unthreaded portion of pipe exposed through a ceiling or wall should be at least how many inches?
• What color is used to identify natural gas piping?
• Which statement about drip tees placement in gas lines is correct?
• Which is the smallest buried underground gas piping size according to the standard?
• What is required to achieve a gas-tight connection when assembling 2 1/2-8 NPT fittings?
• What is the smallest size pipe allowed to be concealed in a wall?
• Anodeless risers are commonly used on plastic gas piping systems in which setting?
• Piping in excess of 5 million BTU must be designed by which professional?
• Which gas component makes up the largest percentage in natural gas?
• What is the Btu?
• What is the function of a regulator in a gas system?
• Which of the following is NOT a recognized method to join gas piping?
• Which statement is true about makeup air calculations for louvers?
• What is the minimum B-vent clearance to combustibles?
• What is the gas pressure test duration commonly required for new piping?
• Single-wall metal flue pipe shall be supported according to which criterion?
• Unvented room heaters permits cannot be issued until which permit is obtained?
• Elevated gas pressure must be labeled at intervals of how many feet?
• Which device is used to provide dilution air to the vent system of a gas water heater?
• The leak test for large gas piping installations shall not exceed what maximum test pressure in psig?
• In the designation, what does 'Diameter And Threads Per Inch' tell you about the thread?
• What is the approximate specific gravity of natural gas relative to air?
• Which category of gas-fired appliance does not create condensate?
• Why are NPT threads tapered in gas piping?
• What is the maximum increment and maximum pressure used when testing gas gauges?
• Which standard governs the form of NPT pipe threads used in gas piping?
• If there are other units present, where should the solenoid valve be placed when converting to an exhaust hood?
• What is secondary air?
• Dual fuels need permission from
• Equipment installed in and made a part of the vent, which will provide a positive induced draft is what?
• Which term describes air that mixes gas before combustion?
• Which statement correctly describes a labeling requirement for elevated piping?
• What is circulating air used for?
• What is the object placed in an appliance to change the direction of, or retard the flow of, air, air-gas mixtures, or flue gases?
• For piping systems over 1,000,000 BTU input, the testing duration is not to exceed how many hours?
• Passageways to gas units on top of buildings shall be not less than how many inches?
• What height must a gas unit heater be above the floor in a residential garage?
• The approximate outside diameter of a 2 1/2 inch nominal pipe is approximately what?
• Which length is the correct maximum for CSST not supported by a listed method on a roof top?
• Outside air for horizontal combustion is defined as an opening size of 1 square inch per 2000 BTU, not less than 3 inches.
• CSST tubing must be directly attached to supports every six feet, which of the following is the correct interval?
• A neutral pH condition is considered to be what value?
• For a 200,000 BTU input appliance, the required combustion air is how many cubic feet?
• What type of joints may only be used with nonferrous pipe and tubing in a gas system?
• When installing gas equipment on roofs inside access is required when the building height is over how many feet?
• The calculation used to supply makeup air through a metal louver must be reduced by what percent?
• Which of the following is a factor used in gas pipe sizing?
• Direct gas fired Industrial Air Heaters may not be utilized unless manufacturer states that there is no more than how many ppm of carbon monoxide in total volume discharged from unit?
• Which NFPA codes are current in Massachusetts for gas installations?
• When installing a gas engine the final connection at the equipment shall be made with a
• Which standard defines pipe thread measurements for natural gas piping?
• When joining 2 1/2-8 NPT fittings, which sealant option is appropriate?
• What type of valve is permitted for the interconnection of standby fuels?
• Which term best describes the first number in the designation '2 1/2-8'?
• In vent sizing, which process uses data points to determine vent sizes?
• The color yellow is used to identify natural gas.
• What is required for gas piping above 70 psig?
• What minimum distance must drip tees have between cap and tee?
• What is the minimum duration of a leak test per 100 feet of piping for large gas piping installations?
• Which term describes air that cools equipment?
• What is the proper clearance distance between a single-wall metal flue pipe and combustibles?
• What is the minimum depth required for burying CSST underground?
• Which of the following is equivalent to 14 inches of water column for CSST pressure?
• An adjustable device for varying the size of the air inlet or inlets regulating primary or secondary air is called what?
• What is the minimum height, in inches, for roof railings near gas units?
• Gas pipe sizing is based on how many factors, and which is an example?
• Underground CSST marker distance from grade?
• Gas appliances on rooftops must have a clearance from unit to roof edge of how many feet?
• The opening in a cap spud or other device whereby the flow of gas is limited and through which the gas is discharged to the burner is
• Maximum length of CSST supported on blocks
• What is the typical gas pressure at the outlet of the natural gas meter?
• Where does dilution air enter the chimney?
• What is the minimum distance required between a forced-air inlet and a mechanical draft vent terminal?
• CSST tubing must be directly attached to supports every
• What is the minimum distance from a cook top to an approved microwave?
• The designation '2 1/2-8' conveys which two primary characteristics?
• What color and lettering should elevated pressure piping labels use?
• What height must a gas unit heater be above the floor in a commercial garage?
• All gaskets used on flanges for gas must be full face for what type of flange material?
• Room heaters shall not be installed bathrooms or bed rooms unless they are direct vented
• What is the normal residential gas pressure regulator setting typically expressed as?
• Combustion air is required at a rate of 50 cubic feet per how many BTU of input?
• For 1/2 inch iron pipe used in a gas system, the threaded portion must be how long?
• The minimum test pressure for gas piping expressed as an equivalent psi is which of the following?
• CSST underground installation requires what regarding marker distance from grade?
• Maximum length of CSST not supported by a listed method shall be supported on a roof top
• Elevated labeling uses the same color scheme as which system?
• What is the maximum size of fittings allowed on low-pressure gas systems?
• What type of control must be installed to limit the excessive pressure in steam boilers or excessive pressure or temperature in hot water boilers?