Utility Emergencies 2014 Flashcards
What is it called when there is a flow of an electric current across a gap between two conductors?
Arc
What is the name for a device which provides transition between underground cable to overhead electrical lines or conductors?
Pothead
What is the path through which electric current is intended to flow called?
Circuit
What is the voltage range for primary electric service lines?
2000 to 50,000
What is the voltage range for secondary electric service lines?
Less than 2,000 volts
How long does electricity need to be out for it to be considered a “sustained outage”?
More than 2 minutes
What is the voltage range generally for transmission lines?
60,000 to 500,000 volts
What is the unit of measure of electric potential called?
Volt
What is the APWA color code for underground electrical lines?
Red
What is the APWA color code for underground gas lines?
Yellow
What is the APWA color code for underground communications lines?
Orange
What is the APWA color code for underground potable water lines?
Blue
What is the APWA color code for underground reclaimed water lines?
Purple
What is the APWA color code for underground sewer lines?
Green
What is the APWA color code for temporary survey markings?
Pink
What is the APWA color code for proposed excavation?
White
What is the vapor density of methane gas?
.55
What is the pungent odorant that is added to the natural gas as a safety precaution?
Mercaptan
When is mercaptan added to natural gas?
At the distribution site
What is the flammable range of natural gas?
between 5% and 15%
What is the ignition temperature of natural gas?
1200 F
What is the primary objective regarding mitigating the hazard of an inside gas leak?
Turn off the gas to the specific appliance, if possible, or shutting off the gas to the entire structure
What is the expansion ratio of natural gas?
600:1
What, typically, is the operating pressure range of gas lines?
.25 to 55 psi
What is the range in size of natural gas transmission lines and what is their upper pressure limit?
6” to 30” and 450psi
What are indicators of a possible pipeline leak?
Hissing or roaring sound
Unusual odor
Dead/discolored vegetation
Fire coming from the ground
Dirt being blown in the air
Water bubbling
A dry spot in a moist field
What are installed at all major vehicular road and railroad crossings to prevent pipeline damage?
Road casings
What are the trade names for flexible natural gas lines which is sometimes used as an alternative to black iron pipe?
Corrugated stainless steel tubing (CSST), Trac Pipe, Ward Flex
What is the proper sequence for shutting off the utility in either a leak or fire situation?
- At the appliance if it can be done safely
- At the meter
- At the curb box
When performing a gas shut off at a curb valve, if the nut for the cover cannot be manipulated, how should the cover be removed?
Use a striking tool to break the cast iron cover
What should be done if the curb box valve cannot be accessed due to debris or dirt?
The curb box should be removed by digging around the box with a shovel
What is the general rule for positioning at a gas leak for the first arriving unit and all other incoming fire apparatus?
No closer than 100’ for the first arriving unit, minimum of 300’ for all others
What shall happen if arriving on scene of a gas leak and there is an odor present?
The apparatus shall be moved immediately
What should crews avoid parking over when responding to a gas leak?
Sewers, valve covers, and manhole covers
When should an outside gas leak be upgraded to a hazardous materials response?
When the break in the line is reported to be over 2” in diameter
What is the initial alarm response for an outside gas leak?
1 Engine, 1 Truck or Rescue
What is a serious hazard, aside from the gas itself, during an outside gas leak?
The build of static electricity ( up to 24,000 volts)
Personnel should not attempt to handle any pipe at the site of an outside gas leak. If it becomes necessary, what should be done prior to coming in contact with it?
An approved grounding device shall be attached
At an outside gas leak, fire department personnel shall ensure no persons enter an un-shored trench that is deeper than what?
5’
To protect the utility company workers, what should FRD units have ready?
20lb dry chem and a charged hoseline
For instances where an outside gas leak cannot be controlled, what should be done?
OIC should confirm utility company is enroute, establish hot/cold zones, and isolate the area
What is the suggested DOT Emergency Response Guide (ERG) evacuation distance for and outside gas leak?
330 feet
When can the mercaptan odorant be eliminated during an outside gas leak?
When the leak is underground and the gas is passed through the soil
Only done during extreme cases, FRD personnel should only consider crimping lines that are what size and smaller?
3/4” or smaller
At what depth are gas lines typically buried below the surface?
24 inches
Which type of piping is most susceptible to static electricity?
polyethylene pipe
What is the best procedure, or course of action, when responding to a gas line on fire?
Protect all exposures until gas is shut off
What is the initial alarm assignment for an inside gas leak?
2 Engines, 1 Truck or Rescue, 1 BC, 1 ems unit if occupants are feeling ill
During an inside gas leak, where should ventilation be started immediately?
Where concentrations are the highest
What should be done prior to shutting down the power at an inside gas leak when the property has a back-up generator?
Secure the generator prior to operating the electric panel
What should be the primary tactic to remove the gases at an inside gas leak?
Natural ventilation
Personnel encountering an odor covering an area inside a commercial/industrial facility should assign a crew to check where?
The roof for any odors from the HVAC units or rooftop service lines
The gas regulator takes street pressure of up to ____ psi and steps it down to between ¼ to ½ prior to the meter.
40
In some new occupancies, gas lines leaving the main regulator are ___ to ___ psi so that the gas can travel longer distances.
2 to 5 psi
How can personnel determine if the gas pressure coming from the main gas meter is at the higher 2 to 5 psi?
There will be another regulator just prior to the appliance
At what pressure do most commercial and all residential appliances use gas?
1/4 to 1/2 psi
To what height should personnel look around a house to try to locate the gas meter or vent pipe?
5 feet
If a gas vent pipe is found on the exterior of a house, the regulator should be within how many feet on the interior of the house?
5 feet
If the gas shut-off on an inside residential installation cannot be operated due to fire or accessibility, where should the gas be shut off?
at the curb box
Most piping located underground in a curb box is usually at what depth?
2-3 feet
In cases where the FD has been called to an inside gas leak with nothing found, the source of the odor might be what?
J, P, or S strap
In the event of an inside gas fire, when the gas meter is involved and access to the meter cannot be accessed, where is the best place to shut off the gas?
At the curb
What is the expansion ratio of propane?
270:1
What is the vapor density of propane?
1.56
What is the LEL and UEL of propane?
LEL 2.3 UEL 9.5
How much does one gallon of propane weigh?
4.23lbs
What is the ignition temperature range of propane?
Between 920F and 1120F
When mercaptan is added to propane, a person with a normal sense of smell should be able to detect a concentration in the air of what percent of the LEL?
20%
At what rate is mercaptan added to liquid propane?
One pound per 10,000 gallons of LPG, equals 1 part per billion
What is the specific gravity of propane?
.505 making it lighter than air
What should engine companies use for vapor dispersion at an outside propane leak?
Two 1 3/4” hoselines with nozzles on narrow fog
At what pressure will the relief valve operate on a propane cylinder?
250psig and 375psig depending on the size of the tank
How much air space does a propane tank need to accommodate the changes in ambient temperature?
20%
What is the best course of action when a propane tank is venting and the product is burning?
Cool the tank and vapor space. If you hear a rising sound from venting safety or discoloration of the tank leave the area immediately
What are the LEL and UEL of carbon monoxide?
12.8% and 74% (128,000 ppm LEL, UEL 740,000)
What is the only way carbon monoxide can enter the body?
Through the respiratory system
What is the initial alarm dispatch for a carbon monoxide emergency?
1 Engine, 1 EMS unit
What is the maximum safe working level over an 8-hour period per OSHA?
35ppm
The EPA has established how many ppm as the max safe level over an 8-hour period?
9ppm
What should be done if the monitoring equipment shows a reading of 35 ppm or above?
The structure should be evacuated immediately
CO readings greater than what PPM is potentially in a lethal range?
100ppm
Per the OSHA standards for CO exposure, at what PPM can lead to a life-threatening frontal headache in 3 hours of CO exposure?
400ppm
When referring to electrical power, what is the term for the pressure or force driving the electric current, also referring to the potential energy?
Voltage
What is the electrical term for the amount of electricity flowing through a wire or conductor and how is it measured?
Current, amps
How fast does electricity travel?
speed of light, 186,000 miles per second
What is the term used to describe the possibility of a person walking near energized downed power lines becoming part of the circuit? Also known as the voltage difference between two points, or ground gradient.
Step potential
One electrical transformer normally carries current to up to how many houses?
10 houses
How far below grade are primary line supposed to be buried?
30 to 36 inches
How far below grade are secondary lines supposed to be buried?
24inches
What is the safest insulator for electricity?
Distance, which is dependent on the voltage and humidity
What is the most hazardous condition involving power lines?
When they don’t contact the ground
How far away from a vehicle should you stay if someone is trapped inside with downed wires?
30 feet
What does the top line for a pole number denote?
Map grid
What does the bottom number for a pole number denote?
Specific pole number
What is off-gassed at vault fires that is especially important to note?
Carbon Monoxide
What is an intermediate space located between regular-use floors of a building, commonly found in hospitals or laboratory type buildings, to allow space for the mechanical systems of the building?
Interstitial space
When navigating in poor visibility, firefighters should when appropriate keep their arms and hands how?
Arms up palms in
Most common CO incidents occur when and from what source?
In the winter and unvented supplemental heaters
When should FFs don their SCBA in a CO incident
35ppm or above
