NFPA 54 National Fuel Gas Code Practice Test

These questions are part of the practice quiz. Start practicing

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