Utility Emergencies Manual, 2ndEdition, April 2014 Flashcards
The flow of an electric current across a gap between two conductors, terminals, or contacts.
Arc
Page 2
A component that detects overload conditions and then disconnects and stops the flow of electrical current to protect and ensure safe operation of the system
Break (or Circuit Breaker)
Page 2
What does BLEVE stand for?
Boiling Liquid Expanding Vapor Explosion
Page 2
A path through which electric current is intend to flow.
Circuit
Page 2
Located at the top of a utility pole, a wooden bar to which power lines are attached.
Cross Arms
Page 2
What is the purpose of cross arms on a utility pole?
The cross arm keeps the lines separated by a sufficient distance to prevent arcing.
Page 2
This links the transmission system to most customers.
Distribution System
Page 2
This is a protective device, consisting of a conducting material, which melts and burns opening the circuit when a specified value is exceeded.
Fuse
Page 2
This means an item is designed to be incapable of producing heat or spark sufficient to ignite an explosive atmosphere.
Intrinsically Safe
Page 2
This is a device, which provides transition between underground cable to overhead lines or conductors.
Pothead
Page 2
Electrical service delivered between 2,000 and 50,000 volts to a distribution transformer, which, in turn, reduces voltage to secondary levels.
Primary
Page 2
This is an automatic protection device that senses and interrupts distribution system faults.
Recloser
Page 3
This is the conductor part of transition leading from underground to overhead; may or may not include pothead.
Riser
Page 3
Electric service taken at less than 2,000 volts. Most residential and business customers receive electricity from these distribution lines.
Secondary
Page 3
The process of opening switches or fuses to divide a circuit into section to isolate the cause of the power outage.
Sectionalize
Page 3
A quarter-turn valve used to restrict or isolate the flow of liquid or gas in a pipe.
Stopcock Valve
Page 3
A location, which uses a collection of transformers to reduce voltage and circuit breakers to protect circuits.
Substation
Page 3
This is an electrical outage that lasts for more than two minutes
Sustained Outage
Page 3
The ratio of the weight of a given volume of gas or vapor to the weight of an equal volume of air at the same temperature and pressure.
Vapor Density
Page 3
The average exposure to a contaminant or condition (such as noise) to which workers may be exposed without adverse effect over a period such as in an 8-hour day or 40-hour week.
Time Weighted Average (TWA)
Page 3
A device, which transforms electric energy from one voltage level to another level.
Transformer
Page 3
This system carries electric power at very high voltages, generally between 60,000 and 500,000 volts. It provides bulk transportation of electricity over long distances, usually from generating sources to substations for voltage reduction.
Transmission
Page 3
The ratio of the weight of a given volume of gas or vapor to the weight of an equal volume of air at the same temperature and pressure.
Less than 1 indicates ____________________?
Greater than 1 indicates ________________?
Vapor Density
Less than 1 indicates it is lighter than air and will rise
greater than 1 indicates heavier than air and will sink
Page 3
A space underground for electric cables, transformers, and other parts of the underground electric system.
Vault
Page 3
The unit of measure of electric potential, which is the condition that causes electric energy to flow.
Volt
Page 3
What are the American Public Works Association’s (APWA) color codes to mark underground utilities?
Red - Electric, cable, conduit, and lighting cable
Yellow - Gas, oil, steam, petroleum or gaseous materials
Orange - Communications, alarm, or signal lines, cable or conduit
Blue - Potable Water
Purple - Reclaimed water, irrigation and slurry lines
Green - Sewer drain lines
Pink - Temporary survey markings
White - Proposed excavations
Page 6
This in gases is defined as the weight of a given volume of gas compared to the weight of the same amount of air at the same temperature and pressure.
Vapor Density
Page 8
What is the vapor density of methane?
0.55
Page 8
Natural gas in its pure state is colorless and odorless. This is a pungent odorant that is added as a safety precaution after it is received at the distribution site.
Mercaptan
Page 8
What is the flammable range for natural gas?
Between 5% and 15%
What is the flammable range for natural gas?
Between 5% and 15%
Page 8
The ignition temperature for nature gas is about ________ degrees F and can easily be ignited by something as simple as a doorbell or a cell phone.
1200
Page 8
What is the expansion ratio of liquefied natural gas to a gas?
600:1
Page 8
What events along the pipeline easement could indicate a pipeline leak?
- A hissing or roaring sound.
- Any unusual odor near the pipeline
- Dead or discolored vegetation in an otherwise green location
- Fire coming from the ground or appearing to burn above the ground
- Dirt being blown or appearing to be thrown into the air.
- Water bubbling or being blown into the air at a pond, creek, or river.
- A dry spot in a most field.
Pages 9 and 10
Firefighters should note the following information concerning marking systems for pipelines:
- Markers show the pipeline’s approximate location; not its exact location
- Signs on the markers list the commodity transported, the name of the pipeline company and a telephone number where company representatives can always be reached.
- Markers do not indicate how deep the pipeline is buried or how many lines are in the area.
- Pipelines do not necessarily follow a straight line between two markers.
Page 10
The proper sequence for shutting off the utility in either a leak or fire situation is as follows:
- At the appliance (if can be safely done).
- At the meter
- At the curb box
Page 12
