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4.1 PERC Gas
4.1 Designing and Installing Exterior Vapor Distribution Systems 2019 Edition
Terms in this set (37)
Effective system load is used to determine the amount of propane required to operate appliances at a reduced demand and assumes the customers appliances _____
Operate at full demand only during typical operating cycles, for example, during a clothes drying cycle or when cooking.
Also that they do not operate simultaneously.
Frost penetration depth in the soil is important to consider when selecting _____.
The two deciding factors for sizing underground tanks are the effective demand of all existing and anticipated future gas appliances and _____.
The maximum anticipated soil frost penetration depth.
Aboveground tanks with less than _____ gallons water capacity may be placed next to a building and must be at least _____ ft horizontally from any building opening that is below the level of discharge.
and 5 feet
The primary factors affecting the rate or extent of corrosion for propane storage containers and vapor distribution piping are _____.
Type of metal and environment in which metal is exposed.
Two commonly used cathodic protection methods are _____.
Sacrificial anodes and impressed current systems.
To prevent regulator freeze-up due to vent blockage caused by ice formation or condensation, the regulator should be mounted so that the _____ to allow drainage of moisture that forms above the diaphragm.
Vent points downward
For a residential vapor distribution system involving a first- and second-stage regulator, the highest Btu/hr output capacity for a single first-stage regulator is not sufficient to meet total gas demand of the system. What is the best solution?
Install two first-stage regulators in a parallel installation.
A circular meter index commonly has four dials that record the volume of gas used. When reading the dials of a circular index, start with the dial _____.
furthest to the right and proceed left.
All of the following are examples of physical defects that would disallow a container to be refilled:
3) Damage to the cylinder foot rings
ASME tanks used for LP-gas storage that have a water capacity of 125 gallons or greater cannot be transported over a public roadway when filled to more than _____ of their water capacity.
Must be under 5% water capacity to transport over public roadways.
The steps to performing a leak test are as follows: Step 1: Select a leak checking device; Step 2: Choose an appropriate place in the plant to perform the inspection; Step 3: _____; Step 4: Use a leak detector to test for leaks.
Pressurize the container
If you are transporting cylinders or tanks containing propane, you must carry a _____.
Shipping papers, a hazmat certificate of registration, and emergency response information.
What are procedures for loading and securing propane cylinders on a vehicle?
1) Park your vehicle at the dock or on the level ground before moving the dolly and cylinder into the lift gate.
2) Take precautions before operating the lift gate, including centering the load on the lift gate to help prevent it from tilting or falling.
3) Load and position the cylinders on the vehicle so that each cylinder's pressure relief valve is in direct communication with the vapor space at all times and secure them in this position.
What must be performed before excavating underground tanks and piping?
1) Confirm the locations of underground utilities.
2) Confirm the locations of customer-owned underground systems
3) Ensure that the buried tank or piping will not interfere with pre-installed utilities or systems.
What is the most important factor affecting the choice of T-Blocks?
Whether the cylinder changeover system is manual or automatic.
When determining a tank location, ensure that it meets what three distance code requirements?
1) Distance from property lines
2) Distance from building
3) Distance from ignition sources
In order to place the tank into service, what must be completed?
1) Verifying the anode wires are properly connected and secure
2) Installing the pigtail, first-stage regulator, and regulator vent pipe.
3) Connecting the buried distribution line to the regulator outlet.
Testing the cathodic protection system can be done by checking the _____.
Tank to-soil potential
Retrofitting is necessary when _____.
Testing determines that installed anodes do not provide sufficient voltage to cathodically protect that system.
Mechanical fittings are used to join PE pipes in most residential and small commercial installations. PE can also be joined using _____.
Do you need to install a tracer wire with PE pipe and tubing?
Yes, because PE pipe and tubing are non-conductive and cannot be found by pipe-locating devices.
Should you use pipe thread-sealing compounds on the seats of brass flare fittings?
No, Flared copper connections are metal-to-metal seals that may not seat and seal properly if you used thread-sealing compounds.
NFPA 58 Specifies that the following types of steel piping can be used for propane vapor distribution systems:
Black iron, galvanized steel, or wrought iron.
When installing CSST, which precaution is true?
Keep the protective plastic jacketing in place to protect the tubing from corrosive threats (wrap it)
Pigtail connectors are used with all of the following groups of regulators:
1) First stage, internal 2-stage, and automatic changeover.
2) First-stage, high pressure, and adjustable high-pressure.
3) First-stage, integral 2-stage, and high pressure.
The NFPA 54 requires that _____ be located in ventilated spaces readily accessible for examination, reading, replacement, or maintenance.
When installing meters at service entrances, two meter-mounting methods are typically used in distribution lines that use independent 2-stage regulation. How can these meters be mounted?
On a building wall or free standing.
The maximum length of time for most temporary heat/construction installations is _____.
Propane grills, fire pits, mosquito traps, illuminating appliances, and patio heaters are all examples of _____.
Outdoor living equipment
When transferring liquid propane from container-to-container; be sure to remove sources of ignition within _____ of the point of transfer, which is the location where hoses connect to the container filler valve and the liquid withdrawal valve.
What are the steps for transferring propane
1) Determine the amount of propane to transfer.
2) Prepare the evacuation site.
3) Connect and inspect pressurized hoses and assemblies.
4) Evacuate liquid propane.
5) Bleed down and disconnect hoses.
What are the safe distances when transferring propane?
No sparking devices within 35 ft
No ignition sources within 25 ft
No engines within 15 ft
There are some differences between DOT containers and ASME tanks that impact evacuation procedures. What are some of them?
1) DOT containers may be transported filled to their legal limit.
2) Not all DOT containers are equipped with vapor return fittings.
3) Not all DOT containers are equipped with float gauges.
A pressure test applies pressure not less than _____ times the proposed maximum working pressure of the interior piping, but in no case less than _____ psig.
1 1/2 times max and 3 psig
A leak test is performed after a leak is identified in a system, and it is performed _____ the test for leakage, pressure test, or leak check.
Flow tests and lock-up tests are typically performed on vapor distribution systems _____ to determine if the piping system and regulator(s) are sized correctly for the estimated load and are functioning properly.
During start up
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