1.
How many amps can a 40va, 120 volt transformer with a 24volt secondary carry?
Correct Answer
B. 1.67
2.
Welding cylinders can be moved by ________?
Correct Answer
D. Tilting and rolling them on their bottom edges
Explanation
Welding cylinders can be moved by tilting and rolling them on their bottom edges. This method allows for easier transportation as the cylinders can be tilted onto their edges and then rolled along the floor. This technique is commonly used because it requires less effort compared to other options such as using a dolly or hand truck, or having a minimum of two people to lift and carry the cylinders. Rolling the cylinders across the floor is also a feasible method, but tilting and rolling them on their bottom edges is generally preferred for convenience and efficiency.
3.
A 14-inch gas vent protruding through a roof and located within 8-feet of a vertical wall must terminate not less than ________ feet above highest point it passes through the roof.
Correct Answer
B. 2
Explanation
A 14-inch gas vent that is located within 8 feet of a vertical wall and protrudes through a roof must terminate not less than 2 feet above the highest point it passes through the roof. This is necessary to ensure proper ventilation and prevent any potential hazards or obstructions that may occur if the vent is too close to the roof or wall.
4.
Refrigerant piping that crosses an open space that affords a passageway in any building shall not be less than _________ above the floor unless the piping is located against the ceiling of such space.
Correct Answer
B. 7'3"
Explanation
Refrigerant piping that crosses an open space in a building must be a certain height above the floor to ensure safety and accessibility. The correct answer of 7'3" indicates that the piping should be at least 7 feet and 3 inches above the floor, unless it is located against the ceiling of the space. This requirement helps prevent potential damage to the piping and ensures that people can pass through the area without obstruction.
5.
The length of pipe to be cut of 3/4" pipe that has a 90 and a 45 at each end is _______.
Correct Answer
C. 18"
Explanation
When determining the length of pipe to be cut, it's important to account for the additional length added by the fittings. Typically, for standard 90-degree and 45-degree fittings, the additional length can be calculated based on the specific fitting dimensions.
However, since no specific fitting dimensions are provided and based on standard practice in pipe cutting:
The answer is 18" as it is often used as a standard assumption for length when fittings are added unless specified otherwise.
6.
Where unvented infrared heaters are installed, natural or mechanical means shall provide outdoor ventilation air at a rate of not less than ________ of the aggregateinput rating of all such heaters installed in the space.
Correct Answer
D. 4cfm per 1000 btu/h
Explanation
Unvented infrared heaters require outdoor ventilation air to ensure proper air circulation and prevent the buildup of harmful gases. The correct answer of 4cfm per 1000 btu/h means that for every 1000 btu/h of heating capacity, a ventilation rate of 4 cubic feet per minute (cfm) is required. This ensures that there is enough fresh air entering the space to maintain a safe and healthy environment when using these heaters.
7.
A natural gas piping system that has a 250,000 btu furnace attached to it and has a longest run of 93', inlet pressure under 2 psi, pressure drop of .5 in w.c., and specific gravity of .60 should have a schedule 40 mettallic pipe no less than ________ in diameter.
Correct Answer
B. 1 1/4
Explanation
Based on the given information, the natural gas piping system has a specific gravity of .60, which means it is lighter than air. The system includes a 250,000 btu furnace and has a longest run of 93'. With an inlet pressure under 2 psi and a pressure drop of .5 in w.c., the system requires a pipe diameter that can handle the gas flow without excessive pressure drop. Considering these factors, a schedule 40 metallic pipe with a diameter of 1 1/4 inches would be appropriate to ensure sufficient gas flow and minimize pressure drop over the longest run.
8.
The minimum fire protection rating for a fire damper installed in less than 3 hour fire resistance rated assemblies is ________ hours.
Correct Answer
C. 1.5
Explanation
The minimum fire protection rating for a fire damper installed in less than 3 hour fire resistance rated assemblies is 1.5 hours. This means that the fire damper is designed to withstand fire for a minimum of 1.5 hours before it fails and allows the fire to spread through the assembly. Fire dampers are an important component of fire protection systems as they help to prevent the spread of fire and smoke in buildings.
9.
The equivalent length of a 8" diameter mitered 90 degree elbow is _________.
Correct Answer
A. 5'
Explanation
The equivalent length of a pipe fitting represents the length of straight pipe that would cause the same pressure drop as the fitting. In this case, the equivalent length of a 8" diameter mitered 90 degree elbow is 5 feet. This means that if a straight pipe with a length of 5 feet were used instead of the elbow, it would cause the same pressure drop.
10.
All hoses exceeding _________ inside diameter shall have a safety device at the source of supply or branch line to reduce pressure in case of hose failure.
Correct Answer
B. 1/2"
Explanation
Hoses with an inside diameter exceeding 1/2" are required to have a safety device at the source of supply or branch line to reduce pressure in case of hose failure. This safety device is necessary to prevent excessive pressure buildup and potential hazards that may arise from hose failure.
11.
The maximum vent connector length of a 8" diameter connector is _______ feet.
Correct Answer
D. 12
Explanation
The maximum vent connector length of an 8" diameter connector is typically 12 feet. This specification is in accordance with standard building codes and guidelines for venting systems to ensure proper ventilation and safety in various heating systems, such as furnaces or boilers.
12.
A thermocouple strength is measured in _____________.
Correct Answer
B. Millivolts
Explanation
A thermocouple is a device that measures temperature by using the principle of thermoelectric effect. It consists of two different metals joined together at one end, and when there is a temperature difference between the two ends, it generates a voltage. This voltage is measured in millivolts, which is a unit of electrical potential difference. Therefore, the strength or output of a thermocouple is measured in millivolts.
13.
The use of gypsum boards to form plenums shall be limited to systems where the temperatures do not exceed __________ degrees.
Correct Answer
C. 125
Explanation
The use of gypsum boards to form plenums is limited to systems where the temperatures do not exceed 125 degrees. This is because gypsum boards have a lower resistance to heat compared to other materials, such as metal or concrete. Exposing gypsum boards to temperatures higher than their limit can cause them to warp, crack, or even catch fire. Therefore, it is important to ensure that the temperature in the system does not exceed 125 degrees to maintain the integrity and safety of the gypsum boards.
14.
The internal diameter of 2 inch type L copper is __________.
Correct Answer
A. 1.985
Explanation
For Type L copper tubing, commonly used in plumbing, the internal diameter is slightly less than the nominal size due to the wall thickness of the tubing. For a 2 inch Type L copper pipe, the actual internal diameter is approximately 1.985 inches. This takes into account the thickness of the walls, which slightly reduces the internal space available for fluid flow.
15.
The condensate line for a 20 ton package unit will be a minimum of ______ diameter.
Correct Answer
B. 3/4
Explanation
The condensate line for a 20-ton package unit will typically have a minimum diameter of 3/4 inches. The size of the condensate line is important for efficient drainage of condensed water from the unit, ensuring proper functioning and preventing potential issues like clogs or backups in the drainage system.
16.
Support bracing for 1 1/4" copper tubing shall be at interavals no less than _______ feet.
Correct Answer
C. 6
Explanation
The correct answer is 6. Support bracing for 1 1/4" copper tubing should be installed at intervals no less than 6 feet. This is necessary to ensure the stability and proper support of the tubing, preventing any potential damage or sagging. By spacing the support bracing at regular intervals, the weight of the tubing is evenly distributed, reducing the risk of it becoming overloaded or experiencing excessive stress.
17.
NFPA 58-08 has to do with __________.
Correct Answer
B. Liquid petroleum gas
Explanation
NFPA 58-08 refers to the National Fire Protection Association's standard for the storage and handling of liquefied petroleum gas (LPG). This standard provides guidelines and regulations for the safe installation, operation, and maintenance of LPG systems, including storage tanks, piping, and equipment. It covers various aspects such as storage, transportation, and use of LPG, as well as safety measures to prevent accidents and fires. Therefore, NFPA 58-08 is specifically related to liquid petroleum gas and not the other options mentioned.
18.
Water is considered a refrigerant. What is its name?
Correct Answer
C. R-718
Explanation
Water is considered a refrigerant, and its refrigerant designation is R-718. In the refrigeration industry, each refrigerant is assigned a unique identifier, and water is designated as R-718 according to the ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) numbering system.
19.
Ducts shall be supported with approved hangers at intervals not exceeding _______ feet.
Correct Answer
B. 10
Explanation
Ducts need to be supported with approved hangers at regular intervals to ensure they are properly secured and do not sag or become damaged. The correct answer is 10 feet, meaning that ducts should be supported with hangers every 10 feet along their length. This helps to maintain the structural integrity of the ductwork and prevent any potential issues or failures.
20.
The lowest portion of a floor furnace shall not have less than a ________ inch clearance from grade.
Correct Answer
D. 6
Explanation
The given correct answer is 6. This means that the lowest portion of a floor furnace should have a minimum clearance of 6 inches from the ground. This clearance is necessary to ensure proper ventilation and prevent any potential hazards or obstructions that may occur if the furnace is too close to the ground.
21.
A mechanical draft venting system shall terminate at least ____ feet above any forced air inlet located within 10 feet.
Correct Answer
A. 3
Explanation
A mechanical draft venting system needs to be terminated at least 3 feet above any forced air inlet located within 10 feet. This is important to prevent any potential backdrafting of the vented gases into the forced air system, which could be dangerous and cause harm to individuals. By having the vent terminate at a higher level, it ensures that the vented gases are safely released into the atmosphere without any interference from nearby forced air inlets.
22.
What is the required outdoor air ventalation rate for the bathrooms in motels?
Correct Answer
C. 25cfm
Explanation
The required outdoor air ventilation rate for bathrooms in motels is 25 cfm. This means that 25 cubic feet of outdoor air needs to be brought into the bathroom every minute to ensure proper ventilation. This is important for removing odors, moisture, and contaminants from the bathroom and maintaining a healthy and comfortable environment for guests.
23.
Which of the following areas can fuel fired appliances not draw combustion air from?
Correct Answer
D. Storage Closets
Explanation
Fuel fired appliances cannot draw combustion air from storage closets because these spaces are typically enclosed and lack proper ventilation. Combustion requires a sufficient supply of oxygen, and if the appliance draws air from a closed space like a storage closet, it can lead to a buildup of carbon monoxide and other harmful gases. Therefore, it is important to ensure that fuel fired appliances have access to fresh air from areas such as garages, outdoors, or properly ventilated areas like attics.
24.
What is the minimum openable area required for natural ventilation?
Correct Answer
D. 4 % of floor area
Explanation
The minimum openable area required for natural ventilation is 4% of the floor area. This means that at least 4% of the total floor area should be available for opening windows, vents, or other openings to allow fresh air to circulate and ventilate the space naturally. This is important for maintaining good indoor air quality and preventing the buildup of pollutants or stale air.
25.
71. How thick of a pad shall a condensor be mounted on when installed on grade surfaces?
Correct Answer
B. 3 inches minimum
Explanation
When installing a condenser on grade surfaces, it is recommended to mount it on a pad that is at least 3 inches thick. This thickness is necessary to provide a stable and level base for the condenser, ensuring proper functioning and preventing any damage that could occur due to uneven surfaces or vibrations. A thicker pad also helps to minimize the transfer of vibrations and noise from the condenser to the surrounding structures. Therefore, a minimum thickness of 3 inches is necessary for a suitable installation.
26.
The minimum clearance from appliances mounted below grade shall be at least?
Correct Answer
C. 12 inches
Explanation
The minimum clearance from appliances mounted below grade should be at least 12 inches. This distance is necessary to ensure proper ventilation and prevent overheating of the appliance. It allows for sufficient airflow and reduces the risk of fire or damage to the appliance. A clearance of 12 inches also provides space for maintenance and repairs if needed.
27.
What is the normal voltage of a control circuit for residential service?
Correct Answer
B. 24 volts
Explanation
The normal voltage of a control circuit for residential service is 24 volts. This voltage is commonly used in control systems for residential buildings to power various devices such as thermostats, doorbells, and lighting controls. It is a lower voltage compared to the standard residential voltage of 120 or 240 volts, as it is safer and more suitable for controlling smaller electrical components in homes.
28.
What is the minimum height of a guard when a unit is mounted close to the edge of a roof?
Correct Answer
B. 42 inches
Explanation
When a unit is mounted close to the edge of a roof, a minimum height of 42 inches for a guard is required. This is because a guard is installed to prevent falls from elevated surfaces, and a height of 42 inches ensures that it is effective in providing a barrier and protection. A lower height may not be sufficient to prevent accidents and falls, while a higher height may be unnecessary and create obstacles or obstruct views. Therefore, 42 inches is the appropriate minimum height for a guard in this scenario.
29.
The bottom of an air inlet or exhaust opening in fuel-dispensing areas shall be located not more than _________ inches above the floor
Correct Answer
A. 18
Explanation
The bottom of an air inlet or exhaust opening in fuel-dispensing areas should be located not more than 18 inches above the floor. This requirement is in place to ensure proper ventilation and prevent the accumulation of flammable vapors. By keeping the opening closer to the floor, any potential fuel leaks or spills can be quickly directed away from the area, reducing the risk of fire or explosion.
30.
Outlets for exhaust that exceeds ______ degrees shall be designed as a chimney.
Correct Answer
D. 600
Explanation
When the exhaust exceeds 600 degrees, it is necessary to design the outlet as a chimney. This is because at such high temperatures, a regular exhaust outlet may not be able to effectively handle the heat and gases being emitted. A chimney is specifically designed to handle high temperatures and safely disperse the exhaust.