Ch. 9: Reading Hazardous Energy Flashcards
Stored potential energy that causes harm if suddenly released.
hazardous energy
The effective ISO categorizes the status of hazardous energy forms in one of the following at incidents:
- Stable - Not likely to change
- Stable - May change
- Unstable - May require attention
- Unstable - Requires immediate attention
What is the integrity of electrical systems based on?
Their being properly grounded, insulated, and circuit protected.
What path is electricity always trying to seek?
Path of least resistance to ground.
What is electrical energy that has established a path to ground through the earth and is energizing it?
ground gradient
What is a downed power line an example of?
ground gradient (may be energizing the earth in a concentric ring of up to 30’ depending on the voltage of the source)
What is a commonplace in many data storage and processing centers, as well as in telecommunication switch equipment centers?
UPS (uninterrupted power supplies) battery rooms
How can pooled water, battery acid, and battery rack hardware become DC energized?
Because there is typically no ground fault protection with DC power.
What catches fire, it may burn for several days, and the heat generated from it can cause serious damage to the tension wire infrastructure?
Transformers because they can hold several thousand gallons of oil.
High tension wires that separate from anchor points can “reel coil” with tremendous force.
When the tension is released suddenly, the wire snaps, or whips, in a direction opposite to the tension force.
What happens when two energies are at play with high tension wires?
1st - Law of motion: For every action (or force), there is an opposite and equal action (force).
2nd - Steel retains a certain memory
What is the integrity of a gas system relied on?
A tight supply vessel (a tank or piping), a shut off valve, a pressure regulation device, and a distribution system with protection at each appliance (shutoff valve and surge protection).
Water and storm sewer systems can cause safety concerns in numerous incident situations.
- Uncontrolled water flow can cause initial and secondary collapses in structures.
- A damaged sewer or storm drain system can leech water into surrounding gravel and dirt beds, undermining, the earth supporting a structure, road, or other utility system.
What will result with water that collects in basements or other building areas that may extinguish gas-fired equipment pilot lights?
The result that raw gas is being “bubbled” into the water.
What can happen to storm sewer systems in flash flood situations?
These systems can be overwhelmed with water and debris.
What are examples of mechanical stored energy?
Systems that include pulleys, cables, counterweights, and springs.
What systems use either hydraulics (liquids) or pneumatics (air/gases) as a medium to achieve power or force?
Pressurized systems
What should be considered when a victim trapped in a vehicle with an undeployed air restraint safety device is in danger?
Consider it an immediate rescue environment
What are the weather considerations that are essential to effective ISO performance?
Wind, humidity, temperature, and the potential for change.
What is by far the most important of all the weather considerations affective firefighting operations?
Wind
Nothing can change a situation faster - or cause more frustration in an operation - than the effects of _______.
wind
How is wind created?
As air masses attempt to reach equilibrium.
From the ISOs perspective, temperature needs to be evaluated relative to its effect on firefighter exposure.
Acclimation is key!
What does a thunder clap that is less than 5 seconds from the flash mean?
You are in the lightning area.
The evacuation of penned, fire-threatened animals is amazingly dangerous.
Have a plan.
Which is the most important of all weather considerations
affecting firefighting operations?
Wind
Up to how many feet can a downed power line energize the ground in a concentric circle?
30
What are the upper/lower (respectively) flammability
limits of propane?
9.5/2.4
Which is NOT a required component for the integrity of
electrical systems?
Sufficiently supplied
How many wind direction and speed changes are common in
the vicinity of a thunderstorm?
4 or 5
Which piece of electrical equipment is a tremendous heat
generator?
Generators
Which is NOT typically a hazard when dealing with a
substation fire?
Pooling water
What is a main concern when fighting fires in low and high humidity environments?
Dehydration
Which is NOT a hazard from the drive/brake system of a
vehicle?
Converter
Which is a common hazard between the suspension/door
system and the drive/brake system?
Springs
Which of the following is NOT a way to categorize
hazardous energy forms?
Stable-may require attention
What can water that has collected in the basement cause to
happen?
Extinguish gas-fire equipment pilot lights
What is the vapor density of propane?
1.5
Which is considered the most important utility control?
Gas
Which is a hazard of a power line?
Under tension
What is the unit of measure for volume of current flow?
Ampere
What is the unit of measure for the amount of energy a
specific appliance uses?
Watt
What factor should you divide the number of seconds
between the lightening flash and the thunder to determine the lightening distance?
5
What is the force that causes the flow of electricity?
Voltage
What can happen when the guide wire releases from a sign?
Recoil with amazing force
Which simple activity is often overlooked that can assist
the ISO in predicting weather that is coming?
Watch the sky
The stronger the container is, the more initial resistance
to pressure it has and the more explosive it becomes when it fails
The stronger the container is, the more initial resistance
to pressure it has and the more explosive it becomes when it fails
Up to how many volts can be used with the bright orange
conduit in a hybrid vehicle?
700
At what size would hail begin to indicate that you are
near the area where a tornado is most likely to form?
1/4 inch
What is the ignition temperature (degrees Fahrenheit) of natural gas (methane)?
999
What is the unit of measure for resistance of electrical
current?
Ohm
What is electrical energy that has established a path to
ground through the earth and that continues to energize
the earth?
Ground gradient
What is the minimum working distance when working around electrical equipment with up to 50,000 volts?
10 feet
