Vermont Natural Gas Certification Practice Test

These questions are part of the practice quiz. Start practicing

• The earliest gas burners that were simply open ends of pipe are referred to as what type of flame burners?
• What is the specific gravity of natural gas?
• Which of the following serves as a switching mechanism in an electrical circuit?
• What does the dew point temperature signify in terms of natural gas combustion?
• Which type of appliance must a clothes dryer NOT be vented with under typical best practices?
• What is the benefit of maintaining correct pitch for venting systems?
• What is the approximate PSI at which VT Gas operates its transmission line?
• What is the heating value of natural gas?
• How much higher must a chimney extend above the point of exit through the roof?
• What type of air is mixed with gas before it reaches the burner port?
• When is a chimney considered to be an exterior chimney?
• If an uncontrolled gas leak ignites, should you extinguish the burning gas flame?
• What happens to flames when gas pressures are unsteady?
• What type of current is generated when a loop of wire is rotated in a gap between the poles of a magnet?
• What does BTU stand for?
• Which of the following is a measure of resistance?
• Which of the following fuels produces carbon monoxide (CO) when burned?
• Gas piping can be used as the grounding conductor if the building ground isn't close by. Is this statement true or false?
• A listed gas connector may pass through a wall provided it's not more than what length?
• Can a natural draft water heater be installed in a bedroom?
• Which factor is critical for maintaining safe levels of combustion air?
• How far must a water heater be installed from the front of an electrical breaker box?
• What is the term for the flow of electric charge in a circuit?
• At what upward pitch should vent connectors be installed?
• Does a steam boiler always need a low water cutoff?
• What type of gas is typically associated with a dryer venting system?
• What is the Vermont OSHA exposure limit for carbon monoxide over an 8-hour period?
• The flow area of the vertical vent or chimney should not exceed how many times the area of the smallest flue collar?
• What is the spacing distance for supports on 3/4" or 1" pipe?
• In Ohm's Law, what does the letter E represent?
• When assessing burner operation, what should you do after changing an orifice size?
• Which type of venting material has been discontinued for Category III appliances?
• Which factor is indicated to negatively affect draft in a venting system?
• Excess flow of what type of air can lead to inefficient combustion?
• In what case can living space air be used for combustion?
• What is essential for the category of an appliance operating under warm and negative pressure conditions?
• What type of gases contribute to a stronger draft in a venting system?
• Is a tall chimney preferable to a short chimney?
• What is one of the focuses of the Vermont Energy Code regarding resource use?
• What is NOT a function of a draft hood?
• A sediment trap is required on all gas equipment. Is this true or false?
• What percentage of free air space do wood air louvers have?
• What is a prime cause of lifting flames in gas burners?
• What is the maximum diameter of threaded fittings permitted above according to NFPA 54?
• What should be done if a gas line breaks?
• What is the term for air naturally available to an appliance?
• Which of the following is NOT a requirement for common venting of multistory systems?
• What defines a direct vent system?
• What gauge wire is generally used in a 20A circuit?
• What is the process of removing combustion gases through a vent called?
• What is the main advantage of B-vent over single wall pipe?
• What is the recommended concentration of carbon monoxide (CO) in flue gasses for most heating and water heating appliances?
• What can excessive primary air lead to in a combustion chamber?
• What venting material is required for Category III appliances?
• What can help eliminate extinction pop by reducing the air supplied to the burner?
• Why is it important to ensure adequate vent capacity when venting appliances?
• What kind of gas is lighter than air?
• What category is assigned to an appliance that has positive vent pressure and experiences condensation?
• The equation for Watt's Law is expressed as?
• Can natural gas appliances be common vented with oil appliances?
• What is the minimum amount of free area required for indoor air openings?
• What is the normal gas pressure inside a customer's home?
• What is required to work on natural gas appliances?
• Is natural gas available in all major cities in Vermont?
• What element of appliance venting is critical for overall safety and efficiency?
• What should be considered when estimating vented combustion air needs?
• Must existing equipment be brought up to code once a new code has been adopted?
• Is natural gas poisonous?
• When is it acceptable to use a common vent for a clothes dryer and other appliances?
• When is a low water cutoff required on a hot water boiler?
• Which of the following is a highly efficient appliance option encouraged by the Vermont Energy Code?
• What component is essential for a clothes dryer when discussing venting systems?
• The flammable limits of natural gas are defined as which of the following percentage ranges?
• What is a primary cause of lifting flames?
• An equipment shutoff valve must be located within how many feet of an appliance?
• What is the upper flammable limit percentage of natural gas?
• Air that passes through an appliance in excess of that required for complete combustion is called what?
• Which elements can lead to inefficient venting in a gas appliance?
• According to Watt's Law, what is the relationship between power, voltage, and current?
• What is the correct response regarding the drafting capabilities in systems with hot exhaust gases?
• How far below any gravity openings must mechanical draft systems be installed?
• Which of the following is NOT a requirement for mechanical draft systems operating under positive vent pressure?
• Which gauge wire is used in a 30A circuit?
• Which of the following is not a sign of carbon monoxide presence?
• What is the chemical formula for methane?
• What is double walled pipe commonly known as?
• What can insufficient secondary air supply to a burner in a combustion chamber cause?
• A transformer is both a ______ and a _______.
• What type of pipe does a B vent represent?
• What is the minimum horizontal distance required for mechanical draft systems?
• When an electrical switch is closed, will electricity flow through it?
• Which openings control the flow of secondary air into a combustion chamber?
• In terms of venting, how should a chimney be treated when replacing or installing a gas furnace?
• For each cubic foot of natural gas, how many cubic feet of air are required for complete combustion?
• How does natural gas compare to air in terms of weight?
• The standard method for calculating the required air volume for combustion is how many cubic feet per BTU per hour?
• Do central heating appliances need to be on a dedicated circuit?
• At approximately what PSI is Compressed Natural Gas transported?
• What does the Vermont Energy Code aim to reduce?
• According to ANSI standards, flue gases should contain less than how many ppm of carbon monoxide?
• What is the term for electrons traveling in one direction from negative to positive?
• For a single natural gas burner requiring 70,000 BTU/hr input at 3.5" w.c. pressure, what size orifice would you choose?
• Which of the following statements about air volume for combustion is true?
• What is a key factor in determining if an appliance should be installed with certain venting conditions?
• When installing a multistory vent system, where must all combustion air come from?
• Is it true that gas piping must be electrically bonded to the building ground?
• For residential gas equipment, what does the term "listed equipment" refer to?
• What occurs when a gas burner experiences overpressurization?
• Does the neutral wire carry current when the circuit is complete?
• In Ohm's Law, what does the letter R stand for?
• What are the three basic elements in any electrical circuit?
• What is the unit of measure for electrical power?
• What is the minimum height above grade for side-wall vent terminations?
• What is the advantage of using double wall pipe?
• Which of the following can result in the spillage of flue products from an appliance draft hood?
• In addition to coated steel pipe, which material does VGS use for its gas mains?
• What is one method NOT typically used for producing natural gas?
• An electromagnetic relay is both a _____ and ______.
• What is the capacity reduction percentage for vent connectors exceeding 1 1/2 feet per inch of vent connector diameter?
• What is the minimum height a chimney or vent should be above the draft hood outlet?
• What restriction do corrugated chimney liners impose on the capacity of Type B gas vents?
• What is indicated by a yellow-tipped flame during combustion?
• What are the three functions performed by draft hoods?
• What is the term for the number of times per second that the electrical output of an AC generator goes through one complete cycle?
• What unit is used to measure electrical current?
• Which appliance typically does NOT require a rigid venting system?
• What is the minimum height required for the exit terminal of a mechanical draft system above a public walkway?
• What happens to the flame when the velocity of the gas-air mixture through the burner ports is reduced below the flame velocity?
• How can flashback on small port burners usually be eliminated?
• What is the optimum burning mixture for natural gas in terms of percentage?
• What is a potential risk associated with improperly vented dryers?
• Which of the following is NOT a common component of natural gas?
• How far should single wall galvanized pipe (C vent) be kept from combustibles?
• When piping through an exterior concrete wall, how must the pipe be treated within the wall?
• Can a clothes dryer be common vented with a water heater provided the vent capacity is adequate?
• In Watt's Law, what does P represent?
• What is a primary concern when choosing fittings for use in concealed locations?
• Which fittings are allowed in concealed locations?
• Which type of air is directly involved in the combustion process at the burner?
• What are three requirements for gas equipment installed in a residential garage?
• What should be done if a chimney's vent connector exceeds the specified limit?
• What must be achieved for complete combustion of natural gas?
• What primarily defines whether a dryer can be common vented with other appliances?
• What is the main cause of gas explosions?
• VT Gas operates its distribution lines at what approximate PSI range?
• What must be done to remaining gas piping when gas appliances are disconnected and removed?
• In electrical terms, what does the letter E denote in the formula P = EI?
• Properly operating natural draft systems create what type of air pressure?
• What is the minimum distance a gas water heater or boiler must be from a 275-gal oil tank?
• Which of the following statements about gas leaks is correct?
• What is the primary purpose of providing dilution air in heating appliances?
• What is the relationship of propane gas to air regarding its weight?
• Which of the following is NOT a method by which natural gas is created?
• How many inches must the exit terminal of a mechanical draft system be above the anticipated slow line?
• What type of air is circulated to supply oxygen and cool the appliance?
• What is the minimum height a B vent must terminate above a roof with a 12/12 pitch?
• What is the primary purpose of secondary air in combustion?
• In an electrical circuit, the term "source" refers to what?
• An appliance with a positive vent pressure that avoids condensation operates under which category?
• Natural gas is mainly comprised of which common hydrocarbon?
• What is the heating value of propane gas?
• After adjusting the gas pressure or changing an orifice, what should you check to ensure correct operation?
• What percentage of vent connector capacity is reduced for every additional 90-degree turn beyond the first two elbows?
• What percentage of air is made up of oxygen?
• What is a critical step when working with gas piping in residential homes?
• A coupling in an electrical setup mainly serves to do what?
• What is the minimum distance double wall (B vent) needs to be from combustibles?
• In building codes, why is venting contractors advised against common venting?
• What does a negative air pressure indicate in a natural draft system?
• Which gas has a heating value close to 2500 btu/cubic foot?
• Is plastic vent piping acceptable for new dryer installations?
• What type of flames will be observed when primary air is insufficient?
• How is the total air used by an appliance for burning fuel referred to?
• To prevent damage to underground facilities, who should be contacted before excavating in a public right-of-way?
• Which measurement indicates the energy content of natural gas?
• What is the minimum level at which a CO detector will alarm in parts per million (PPM)?
• Are natural gas appliances typically common vented with wood burning appliances?
• What are the primary byproducts of the complete combustion of natural gas?
• What type of vent pipe is required when passing through attics, floors, or inside walls?
• What is the lower flammable limit percentage of natural gas?
• For a mechanical draft system, what is one of the critical components that ensures safety?
• In addition to natural gas, which other fuel is known to create CO?
• Which statement is true regarding the installation of heating appliances under the Vermont Energy Code?
• What are three visual indicators that carbon monoxide may be present in a home?
• What is the importance of sealing all joints in a mechanical draft system?
• What is the specific gravity of propane?
• Which type of fuel is NOT typically a source of carbon monoxide?
• What is the minimum ignition temperature of natural gas in degrees Fahrenheit?
• The specific gravity of a gas is a ratio of its density to the density of what?
• Using a 1/2 cu. ft per revolution dial on a meter, if it takes 40 seconds for one revolution, what is the gas flow rate in BTU/hr?
• What gauge wire is typically used in a 15A circuit?
• In an electrical outlet receptacle, which slot is supposed to be the neutral side?
• What is the minimum height a chimney must be above the highest point of the roof within a horizontal distance of 10 ft?
• Which of the following best describes carbon monoxide?
• A device which uses electrical power is also called a _____.
• What role does a load play in an electrical circuit?
• Is natural gas odorless?
• Which safety measure can help prevent issues when venting a clothes dryer with a water heater?
• What can be a consequence of inadequate vent capacity in a common venting system?
• How should combustion air openings be sized for appliances?
• Which property of a gas determines how it behaves when mixed with air?
• What fitting is not allowed in a concealed location?
• How long must a pressure test last in a residential home?
• What is the correct response to the statement: "The chimney must be left unlined when venting into an unlined chimney?"
• Which organization sets the standards that dictate the regulations for gas piping installations?
• What is the minimum test pressure for gas piping in residential homes?
• Why is it important to adhere to the Vermont Energy Code?
• In Ohm's Law, what does the letter I represent?
• What is the heat input rate (BTU) per hour for a natural gas flow of 80 cu ft/hr?
• Which of the following statements is accurate regarding venting appliances?
• NFPA 54 does not permit threaded fittings above _____ inches diameter.
• Is purging required if placing 100ft of 3" pipe into operation?
• In a space of 8' x 20' x 20', what is the required air volume for a 100,000 btu/hr furnace and an 80,000 btu/hr water heater?
• What percentage of free air space do metal air grills have?
• How much energy does it take to raise 1 lb of water 1 degree, in BTU?
• What type of pipe should be used for running underground to a pool heater?
• Which condition can lead to the formation of yellow-tipped flames in a combustion process?
• What is the force of electrical "pressure" called?
• Why might venting a dryer and water heater together be discouraged?
• If the velocity of the gas exceeding the flame velocity, what will occur with the flame?
• In case of an uncontrolled escape of gas, what should be the FIRST priority?
• What is the term for air supplied to a flame at the point of combustion?
• What is the approximate dew point temperature at which water vapor from natural gas combustion condenses?
• Can copper be used indoors for natural gas piping in VGS territory?
• An appliance that operates with negative vent pressure and a warm temperature is categorized as which type?
• What is the percentage of nitrogen in the air?