Question 1

Venturi effect

Accepted Answer

The reduction in fluid pressure that results when a fluid flows through a constricted section of pipe.

Question 2

Manometer

Accepted Answer

A device used to measure the pressure of gas in a system, usually expressed in inches of water column.

Question 3

Pilot flame

Accepted Answer

A small, continuous flame used to ignite the main burner in a gas appliance.

Question 4

Gas valve

Accepted Answer

A device that controls the flow of gas to an appliance, typically operated by a thermostat or other control mechanism.

Question 5

Intermittent ignition

Accepted Answer

An ignition system that only provides a spark or pilot flame when the appliance requires heat.

Question 6

Oxygen depletion sensor (ODS)

Accepted Answer

A safety device that shuts off the gas supply if the oxygen level in the room falls below a certain threshold.

Question 7

Thermocouple

Accepted Answer

A temperature-sensing device used to generate a small electric current, typically used to control a gas valve.

Question 8

Orifice

Accepted Answer

A small hole or opening in a gas burner through which the gas is released and mixed with air before ignition.

Question 9

Gas pressure regulator

Accepted Answer

A device that maintains a constant gas pressure for appliances by reducing the incoming high pressure to a lower, more manageable level.

Question 10

Flue gas analysis

Accepted Answer

The process of measuring the composition of flue gases to ensure efficient combustion and proper venting of an appliance.

Question 11

British thermal unit (BTU)

Accepted Answer

The amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit.

Question 12

Air-gas ratio

Accepted Answer

The ratio of air to fuel in a combustion process, critical for efficient and safe operation of gas appliances.

Question 13

Draft hood

Accepted Answer

A device that prevents downdrafts and backdrafts from affecting the combustion process in a gas appliance.

Question 14

Low pressure system

Accepted Answer

A gas distribution system that operates at pressures below 14 inches of water column.

Question 15

High pressure system

Accepted Answer

A gas distribution system that operates at pressures above 14 inches of water column.

Question 16

Combustible gas detector

Accepted Answer

A device used to detect the presence of combustible gases, such as natural gas or propane.

Question 17

Gas meter

Accepted Answer

A device used to measure the volume of gas consumed by an appliance or building.

Question 18

Combustion air

Accepted Answer

The air required for the complete combustion of a fuel, typically supplied from the surrounding environment.

Question 19

Excess air

Accepted Answer

The amount of air supplied to a combustion process beyond what is required for complete combustion.

Question 20

Incomplete combustion

Accepted Answer

A condition where not all of the fuel is burned, leading to the production of harmful byproducts, such as carbon monoxide.

Question 21

Carbon monoxide (CO)

Accepted Answer

A colorless, odorless, and toxic gas produced by incomplete combustion of hydrocarbon fuels.

Question 22

Yellow flame

Accepted Answer

A sign of incomplete combustion, indicating insufficient air supply or poor mixing of air and gas.

Question 23

Gas leak

Accepted Answer

An unintended escape of gas from a system or appliance, which can lead to hazardous conditions.

Question 24

Confined space

Accepted Answer

An enclosed space with limited access, posing a risk of oxygen deficiency, accumulation of toxic or flammable gases, or other hazards.

Question 25

Atmospheric burner

Accepted Answer

A type of gas burner that relies on natural draft for air supply and venting.

Question 26

Forced draft burner

Accepted Answer

A type of gas burner that uses a fan or blower to supply combustion air and exhaust flue gases.

Question 27

Gas appliance connector

Accepted Answer

A flexible metal hose used to connect a gas appliance to the gas supply.

Question 28

Purging

Accepted Answer

The process of removing air or other contaminants from a gas piping system, typically by introducing gas at a controlled rate.

Question 29

Lockout/tagout

Accepted Answer

A safety procedure to prevent accidental energizing or starting of equipment during maintenance or servicing.

Question 30

Heat exchanger

Accepted Answer

A device that transfers heat from the combustion process to the medium being heated, such as air or water.

Question 31

Condensing appliance

Accepted Answer

A high-efficiency gas appliance that extracts additional heat from flue gases by condensing water vapor, resulting in lower exhaust temperatures and increased energy efficiency.

Question 32

Gas train

Accepted Answer

A series of components, such as valves, regulators, and safety devices, that control the flow of gas to an appliance.

Question 33

Standing pilot

Accepted Answer

A small, continuous flame that is always lit, used to ignite the main burner in a gas appliance.

Question 34

Flame rectification

Accepted Answer

A method used to detect the presence of a flame in gas appliances, which relies on the ability of a flame to conduct a small electrical current.

Question 35

Spillage

Accepted Answer

The unwanted release of combustion products, such as flue gases, into the living space or surrounding environment.

Question 36

Flow control valve

Accepted Answer

A valve that regulates the flow of gas or liquid through a system, typically by adjusting the size of an orifice.

Question 37

Gas cock

Accepted Answer

A manual shutoff valve used to control the flow of gas to an appliance.

Question 38

Appliance pressure test

Accepted Answer

A test performed on a gas appliance to ensure there are no leaks in the gas piping or components.

Question 39

Drip leg

Accepted Answer

A section of pipe installed vertically to collect and remove condensation or debris from a gas piping system.

Question 40

Gas line sizing

Accepted Answer

The process of determining the appropriate size of gas piping needed to supply an appliance based on its BTU requirements and the length of the pipe run.

Question 41

Relief valve

Accepted Answer

A safety device that releases gas or liquid when the pressure in a system exceeds a predetermined limit.

Question 42

Flashback arrestor

Accepted Answer

A device used to prevent flame or ignition from traveling back into the gas supply system, protecting against explosions.

Question 43

Flame safeguard

Accepted Answer

A control system that monitors the presence of a flame in a gas appliance and shuts off the gas supply if the flame is lost.

Question 44

Barometric damper

Accepted Answer

A device installed in the flue pipe of an appliance that helps maintain proper draft by automatically adjusting to changes in atmospheric pressure.

Question 45

Gas pipe joint compound

Accepted Answer

A sealant used on threaded gas pipe connections to ensure a leak-free seal.

Question 46

Infrared burner

Accepted Answer

A type of gas burner that uses radiant heat to cook food, providing even heating and reducing flare-ups.

Question 47

Venting

Accepted Answer

The process of safely removing combustion byproducts, such as flue gases, from an appliance to the outdoors.

Question 48

Direct vent appliance

Accepted Answer

A gas appliance that draws combustion air from the outdoors and vents combustion byproducts directly outside, rather than relying on indoor air.

Question 49

Induced draft

Accepted Answer

A method of venting that uses a fan or blower to draw combustion air into an appliance and exhaust flue gases.

Question 50

Category IV appliance

Accepted Answer

A high-efficiency, condensing gas appliance that operates with a positive vent pressure and requires a sealed venting system.

Question 51

Gas code

Accepted Answer

A set of rules and regulations governing the installation, operation, and maintenance of gas systems and appliances, such as the National Fuel Gas Code (NFPA 54).

Red Seal Exam Gasfitter - Class B: Advanced Flashcards