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Gas Technician 2 Training
Module 10
Piping and Tubing Systems for Industrial and
Commercial Applications
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Unit 1
Code Requirements and
Approved Joining Methods
Purpose
The installation of gas piping and tubing is
a basic part of a gas technician’s duties.
The student must be aware of the code
requirements concerning approved types
of piping and tubing, as well as applicable
joining methods. Pipe sizes, locations and
pressures are all factors that must be
considered before a piping or tubing
system is installed.
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Unit 1
Code Requirements and
Approved Joining Methods
Learning objectives
1. Describe the Code requirements for
industrial and commercial applications.
2. Describe the joining methods that may be used.
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Code requirements for industrial
and commercial piping applications
 Allowable pressures
 Pressure testing requirements
 Underground piping
 Identification of gas piping
 Shut-off valves
 Commercial cooking appliances
Module 10
Unit 1
Topic 1
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Module 10
Unit 1
Figure 1-1
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Module 10
Unit 1
Figure 1-2
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Module 10
Unit 1
Figure 1-3
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Module 10
Unit 1
Figure 1-4
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Module 10
Unit 1
Figure 1-5
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Module 10
Unit 1
Figure 1-6
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Module 10
Unit 1
Figure 1-7
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Module 10
Unit 1
Figure 1-8
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Approved joining methods
 General requirements of piping, tubing and
connectors
 Piping material and fittings
 Joints and connections in large-size piping
 Iron and galvanized steel piping
 Other types of piping and tubing
Module 10
Unit 1
Topic 2
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Answer Key
Assignment 1
1. State a Code practice during installation of piping
and tubing that will ensure the system stays leakfree for years to come.
 Visually inspect pipe, tube and fittings.
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Answer Key
Assignment 1
2. Describe the first pressure test of the system, before
appliances are connected.
 Before the appliances are connected, the system shall be
tested using air or inert gas. Meters regulators and shutoff valves not rated for the test pressure shall not be
connected to the system.
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Answer Key
Assignment 1
3. When and Where would you perform a soap test?
 When a leak is indicated by a drop in pressure, every joint
and fitting must be checked.
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Answer Key
Assignment 1
4. What must be done to piping or tubing passing
through concrete?
 It must be sleeved, coated, or double-wrapped.
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Answer Key
Assignment 1
5. May a sleeve installed in pavement to allow free movement
of the pipe also serve as a vent pipe inspection point?
 Yes
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Answer Key
Assignment 1
6. List three methods of identifying gas piping inside a
commercial or industrial building.
a) The entire system shall be painted yellow.
b) The system shall be provided with yellow
banding.
c) Utilizing yellow labels, the system shall be
marked “Gas” or “Propane”
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Answer Key
Assignment 1
7. How would you recognize a manual shut-off valve as
being approved for installation in a natural gas or propane
system?
 It shall be of the plug, ball or eccentric type and shall not
be subjected to greater temperature or pressure greater
than its rating.
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Answer Key
Assignment 1
8. How must multiple outlets that are installed in a
laboratory (school or other), be protected from
leaking gas into the area accidentally?
 A clearly marked, readily accessible, master shut-off
valve.
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Answer Key
Assignment 1
9. Joints in steel piping used in gas systems shall be:
 Threaded, flanged or welded.
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Answer Key
Assignment 1
10. List all approved gasket material for gas systems
and why natural rubber is not approved.
 Neoprene or other similar material resistant to any
action of gas. Natural rubber may dry or crack as it is
not impervious to the action of gas.
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Unit 2
Welding Safety, Certification
and Procedures
Purpose
A gas technician is not required to hold any
type of welding certification, however a
thorough knowledge of the requirements for
welded gas piping is important. This, along
with an understanding of welding procedures
and welding related hazards, is vital to a safe
and secure installation.
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Unit 2
Welding Safety, Certification
and Procedures
Learning objectives
1. Describe some of the common welding hazards.
2. Describe the safety preacuations that need to be taken.
3. Describe the certification requirements.
4. Describe the preparation that is required for welding
testing.
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Common hazards
 Physical hazards
Ionizing radiation
Non-ionizing radiation
Fire, flying hot metal sparks, etc.
Noise
 Chemical hazards
Pure oxygen
Acetylene
Other chemical hazards
 Environmental hazards
Module 10
Unit 2
Topic 2
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Module 10
Unit 2
Figure 2-1
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Module 10
Unit 2
Figure 2-2
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Module 10
Unit 2
Figure 2-3
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Safety precautions
 Protective clothing
 Fire prevention
 Oxy-Acetylene equipment
Module 10
Unit 2
Topic 2
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Module 10
Unit 2
Figure 2-4
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Certification requirements
 Welders are required to meet the
standards set out in B.0 of the Boilers and
Pressure Vessels Act.
 Before performing any work requiring
welded pipe, contact the provincial gas
safety branch for specific certification
requirements in your province.
Module 10
Unit 2
Topic 3
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Preparation for welding
 Measuring pipe and fittings
 Common weld fittings
 Marking the cutting line
 Cutting pipe and tubing
 Pipe and fitting alignment
 Joint assembly
 Tacking
Module 10
Unit 2
Topic 4
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Module 10
Unit 2
Figure 2-5
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Module 10
Unit 2
Figure 2-6
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Module 10
Unit 2
Figure 2-7
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Module 10
Unit 2
Figure 2-8
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Module 10
Unit 2
Figure 2-9
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Module 10
Unit 2
Figure 2-10
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Module 10
Unit 2
Figure 2-11
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Module 10
Unit 2
Figure 2-12
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Module 10
Unit 2
Figure 2-13
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Testing
 Radiographic testing
 Liquid (dye) penetrant examination
Module 10
Unit 2
Topic 5
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Answer Key
Assignment 2
1. The three general categories of major welding hazards
to workers in the vicinity of welding operations are:
a) Physical
b) Chemical
c) Environmental
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Answer Key
Assignment 2
2. State the adverse health effects from exposure to welding
X-ray equipment.
 The equipment emits ionizing radiation by way of Xrays
and gamma rays which can cause extreme damage to
unprotected parts of the body.
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Answer Key
Assignment 2
3. List the adverse effects from ultraviolet radiation
produced by arc welding.

It causes burning of unprotected eyes and skin.
Eyeballs and skin may blister. These conditions may
last hours or days.
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Answer Key
Assignment 2
4. After welding is completed in an area where
combustible material is present, how long should a
“fire watch” be maintained?
At least 20 minutes
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Answer Key
Assignment 2
5. List the types of personal protective equipment that
must be worn when working with or around a welder.
 Heavy clothing (free of oil or grease), eye and face
protection, gauntlet-type gloves, steel-toed boots, a
cap, cuffless pants, and—when required—masks or
respirators.
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Answer Key
Assignment 2
6. List two important safety precautions to be observed
when working with an oxygen cylinder.
 Keep oil and grease away from the oxygen and never
attempt to repair a faulty cylinder.
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Answer Key
Assignment 2
7. Is acetylene a very stable gas that is easily compressed to
high pressures?
 No
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Answer Key
Assignment 2
8. What should be done if welding is taking place in a
confined area?
 Ensure adequate ventilation.
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Answer Key
Assignment 2
9. What type of gloves should be worn around welding
operations?
 Gauntlet-type
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Answer Key
Assignment 2
10. Should oxygen and acetylene regulators be oiled
regularly?
 No
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Answer Key
Assignment 2
11. How many air changes per hour are required in a
welding shop?
 Four
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Answer Key
Assignment 2
12. With what are oxygen and acetylene cylinders fitted to
minimize the possibility of explosion in case of fire?
 Fusible plugs
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Answer Key
Assignment 2
13. To what angle should pipe be bevelled if it is to be
welded?
 Approximately 37 1/2°
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Answer Key
Assignment 2
14. When the pipe an fittings are set up for welding, how
wide is the root gap?
 1/16 inch to 1/8 inch
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Unit 3
Utility and Non-Utility Piping
Purpose
A gas technician must be prepared to install
various types of pipe and tubing, as well as
recognize many other types. Piping can carry
substances other than gas, and the type of
piping is not always an indicator of what is
inside. A basic understanding of how piping is
identified on drawings, and on the worksite, is
important to ensure installation and repairs are
done safely and efficiently.
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Unit 3
Utility and Non-Utility Piping
Learning objectives
1. Describe utility piping.
2. Describe non-utility piping.
3. Distinguish gas piping from other types of piping.
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Utility piping
 Underground piping
 Underground tubing
Module 10
Unit 3
Topic 1
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Non-utility piping and tubing
 Most non-utility gas piping and tubing is run
above ground.
 Piping downstream of a gas utility meter is
usually the responsibility of the property or
building owner.
Module 10
Unit 3
Topic 2
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Identification and tracing
 Type of pipe, colour coding and marking
Underground gas piping and tubing
Underground piping and tubing, other than gas
Above-ground piping and tubing
 Blueprint identification
 Tracing
Module 10
Unit 3
Topic 3
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Answer Key
Assignment 3
1. What size is the tracer wire (a) on underground gas
piping? (b) What material is it made of?
a) Minimum 16 gauge
b) Copper
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Answer Key
Assignment 3
2. Who is responsible for piping downstream of the meter?
 The property or building owner
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Answer Key
Assignment 3
3. Coatings on underground steel pipe are made of (a) what
material; and (b) in which colour(s)?
a) Polyethylene
b) Yellow or Blue
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Answer Key
Assignment 3
4. Above-ground gas piping shall be identified by one of
which two methods?
a) Yellow paint or
b) Yellow banding
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Answer Key
Assignment 3
5. The final drawings on a job are called:
 As-built drawings
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Answer Key
Assignment 3
6. The surest way to identify contents of a sealed pipe is to:
 Trace it back to its source.
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Unit 4
Piping Layout, Drawings and
Symbols
Purpose
Before installing any equipment, the gas
technician must have a plan. The plan must
take into consideration things like how, what,
where and when. The plan can be very simple,
such as setting up a small gas barbecue, or
very complex, such as for heating a large
office building. In many cases the basic plan
will be supplied through blueprints and
specifications. Documents such as these, and a
knowledge of how to read and apply them, will
ensure that the piping layout and installation
goes ahead with a minimum of problems.
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Unit 4
Piping Layout, Drawings and
Symbols
Learning objectives
1. Explain blueprints and specifications.
2. Describe valves.
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Blueprints and specifications
 Blueprints
 Specifications

Precedence of specifications
 Interpreting instructions and symbols
 Manufacturers’ installation data

Model number

Tools and hardware

Wiring and piping

Replacement parts
Module 10
Unit 4
Topic 1
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Module 10
Unit 4
Figure 4-1
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Module 10
Unit 4
Figure 4-2
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Module 10
Unit 4
Figure 4-3
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Module 10
Unit 4
Figure 4-4
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Module 10
Unit 4
Figure 4-5
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Module 10
Unit 4
Figure 4-6
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Valves
 Manual
 Gate valves
 Globe valves
 Jointing methods for manual valves
 Automatic
 Solenoid valve
 Manual/Automatic
Module 10
Unit 4
Topic 2
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Module 10
Unit 4
Figure 4-7
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Module 10
Unit 4
Figure 4-8
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Module 10
Unit 4
Figure 4-9
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Module 10
Unit 4
Figure 4-10
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Module 10
Unit 4
Figure 4-11
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Answer Key
Assignment 4
1. If there is a discrepancy between the specifications and
the drawings:
a) which one is taken to be correct?
b) State the reasons for your answer
a) Specifications
b) The specifications generally reflect final decisions and
written instructions are more acceptable in a court of
law.
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Answer Key
Assignment 4
2. The manufacturer’s installation and service manual is
supplied with every appliance. How much of it should
you read?
 All of it
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Answer Key
Assignment 4
3. Do the installation and service manuals supplied by the
manufacturer always specify details of replacement parts?
 No
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Answer Key
Assignment 4
4. The two ways that manual valves are joined to the gas
piping systems are:
a) Threaded
b) Flanged
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Answer Key
Assignment 4
5. What two functions do automatic valves perform?
a) Control, firing of the burner
b) Safety shut-off
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Answer Key
Assignment 4
6. Describe the function of a solenoid valve.
 To energize (open) on a call for heat and de-energize
(close) when the heat demand is satisfied.
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Unit 5
Size High-Pressure Piping
and Tubing
Purpose
To ensure that gas equipment will operate to
design specifications, it must receive the
correct amount of gas. One of the main factors
governing gas flow is pipe size. The gas
technician must be aware of the procedure
used to determine the correct pipe size. An
organized and methodical approach to sizing
will result in the correct size being determined.
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Unit 5
Size High-Pressure Piping
and Tubing
Learning objectives
1. Explain the use of sizing tables.
2. Describe the general sizing procedure.
3. Describe the high-pressure sizing procedure.
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Use of tables
 Pressure drop
 Copper tube
 Natural gas vs. propane gas
Module 10
Unit 5
Topic 1
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General sizing procedure
Procedural steps
Step 1. Sketch the system
Step 2. Select a table
Step 3. Determine Code zone
Step 4. Size pipe sections
Step 5. Prove Code zone is correct
Step 6. Consult Code table
Proof of procedure
Module 10
Unit 5
Topic 2
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Module 10
Unit 5
Figure 5-1
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Module 10
Unit 5
Figure 5-2
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High-pressure sizing procedure
 Summary
 Natural gas example 1 (Imperial)
 Natural gas example 2 (Metric)
 Propane example 3 (Imperial)
Module 10
Unit 5
Topic 3
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Module 10
Unit 5
Figure 5-3
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Module 10
Unit 5
Figure 5-4
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Module 10
Unit 5
Figure 5-5
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Module 10
Unit 5
Figure 5-6
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Module 10
Unit 5
Figure 5A2
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Module 10
Unit 5
Figure 5A3
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Module 10
Unit 5
Figure 5A4
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Module 10
Unit 5
Figure 5A5
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Module 10
Unit 5
Figure 5A6
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Answer Key
Assignment 5-1
1. Why are there different sizing tables in the Code for (a)
copper tubing and (b) steel pipe?
a) The inside surface textures and inside diameters are
different.
b) The densities of the gases are different.
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Answer Key
Assignment 5-1
2. State the five procedural steps when pipe sizing.
i) Sketch the system.
ii) Select a table.
iii) Determine the Code zone.
iv)Size pipe sections.
v) Prove the Code zone (if pressure is over 2 psi)
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Answer Key
Assignment 5-2
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Answer Key
Assignment 5-2…/continued
Table:
Natural gas
Welded iron pipe, forged tees
5 psi with 2.5 psi pressure drop
Table is A.5(a)
Code Zone:
LMR A = 80 ft
LMR B = 85 ft
CZ is 100 ft
Section
MBtu/h
Size
Max. Load MBtu/h
A
B
C
1500
3000
4500
¾ inch
1 inch
1¼ inch
1685
3173
6515
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Answer Key
Assignment 5-2…/continued
Proof A:
4-1¼ inch 90
2-1¼ inch T
2-¾ inch 90
1-¾ inch T
1-¾ inch valve
Total equivalent of fittings
Length of measured run
Length of equivalent run
1.38
5.17
0.82
3.09
2.06
5.52
10.34
1.64
3.09
2.06
22.65
80.00
102.65
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Answer Key
Assignment 5-2…/continued
The LER is too long, so we resize on the next CA:
LMR A = 80 ft
LMR B = 85 ft CZ = 125 ft
Section
A
B
C
MBtu/h
1500
3000
4500
Size
1 inch
1¼ inch
1¼ inch
Max. Load MBtu/h(H)
2813
5774
5774
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Answer Key
Assignment 5-2…/continued
Proof A:
4-1¼ inch 90
2-1¼ inch T
2-1 inch 90
1-1 inch T
1-1 inch valve
Total equivalent of fittings
Length of measured run
Length of equivalent run
1.38
5.17
1.05
3.93
2.62
5.52
10.34
2.10
3.93
2.62
24.51
80.00
104.51
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Answer Key
Assignment 5-2…/continued
Proof B:
4-1¼ inch 90
2-1¼ inch T
1-1¼ inch valve
Total equivalent of fittings
Length of measured run
Length of equivalent run
1.38
5.17
3.45
5.52
10.34
3.45
19.31
85.00
104.31
LER of B is shorter than that of run A, so the LER of the
system is 104.51 ft.
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Answer Key
Assignment 5-3
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Answer Key
Assignment 5-3…/continued
Table: Natural gas
Iron pipe, welded fittings
5 psi with 2.5 psi pressure drop
Table is A.5(a)
Code Zone:
LMR B =
CZ
=
91 ft
125 ft
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Answer Key
Assignment 5-3…/continued
Section
A
B
C
D
E
F
G
MBtu/h
900
2500
9000
3000
12 000
13 500
15 400
Size
¾ inch
1 inch
2 inches
1¼ inch
2 inches
2 inches
2 inches
Max. Load Mbtu/h
1493
2813
16 662
5774
16 662
16 662
16 662
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Answer Key
Assignment 5-3…/continued
Proof B:
1-1 inch valve
1-1 inch T
3-1 inch 90
2-2 inches T
2-2 inches 90
2.62
3.93
1.05
7.75
2.07
2.62
3.93
3.15
15.50
4.14
Total equivalent of fittings
Length of measured run to B
29.34
91.00
Length of equivalent run
120.34
The Code Zone is OK.
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Answer Key
Assignment 5-4
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Answer Key
Assignment 5-4…/continued
Sizing the low-pressure system:
The piping system contains a system regulator, with a lowpressure system of 7 inches w.c. We will size the low-pressure
sytem first.
Table:
Natural gas
Iron pipe, threaded fittings
7 inches w.c. with 1 inch w.c. pressure drop
Table is A.2(a)
Code Zone:
LMR
CZ
=
=
54 ft
60 ft
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Answer Key
Assignment 5-4…/continued
Section
1
2
3
4
5
MBtu/h
Size
Max. Load MBtu/h
120
65
40
185
225
¾ inch
½ inch
½ inch
1 inch
1 inch
180
86
86
339
339
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Answer Key
Assignment 5-4…/continued
Sizing the high pressure system:
Table:
Natural gas
Iron pipe, threaded fittings
5 psi with 2.5 psi pressure drop
Table is A.5(a)
Code Zone:
LMR A =132 ft
CZ
=175 ft
Section
MBtu/h
Size
Max. Load Mbtu/h
4000
6000
10 000
10 225
225
1¼ inch
1½ inch
2 inches
2 inches
½ inch
4813
7212
13 889
13 889
595
A
B
C
D
E
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Answer Key
Assignment 5-4…/continued
Proof A:
4-2 inches 90
2-2 inches T
1-1¼ inch 90
1-1¼ inch valve
5.17
10.30
3.45
3.45
20.68
20.60
3.45
3.45
Total equivalent length of fittings
Length of measured run to B
48.18
132.00
Length of equivalent run
180.18
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Answer Key
Assignment 5-4…/continued
The LER is too long, so we resize on the next CZ: CZ = 100 ft
Section
A
B
C
D
E
MBtu/h
4000
6000
10 000
10 225
225
Size
1¼ inch
1½ inch
2 inches
2 inches
½ inch
The pipe size does not change, so the Code zone is 200 ft and
the LER is 180.18 ft.
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Answer Key
Assignment 5-5
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Answer Key
Assignment 5-5…/continued
Table
Type of pipe
Natural Gas
Size
Maximum
Iron pipe,
pipe:
Load
welded fittings
System pressure
34kPa
A 293 kW ¾ inch
396kW
Allowable pressure drop 17kPa
B 805 kW 1¼ inch
1533kW
Sizing table
A.5(b)
C 3000kW 2 inches
4423kW
D 1170kW 1¼ inch
1533kW
E 4170kW 2 inches 4423kW
LMR=30m
F 4975kW 2½ inches 7050kW
CZ=45m
G 5268kW 2½ inches 7050kW
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Answer Key
Assignment 5-5…/continued
Proof G-B:
2-2½ inches 90
2-2½ inches T
3-1¼ inch 90
1-1¼ inch T
1-1¼ inch valve
@ 0.75 m
@ 2.82 m
@ 0.42 m
@ 1.58 m
@ 1.05 m
=
=
=
=
=
1.50 m
5.64 m
1.26 m
1.58 m
1.05 m
Total equivalent length of fittings
Length of measured run
11.03 m
30.00 m
Length of equivalent run
41.03 m
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Answer Key
Assignment 5-5…/continued
Proof G-C:
3-2 inches 90
2-2 inches T
1-2 inches valve
1-2½ inches T
2-2½ inches 90
@ 0.63 m
@ 2.36 m
@ 1.58 m
@ 2.82 m
@ 0.75 m
=
=
=
=
=
1.89 m
4.72 m
1.58 m
2.82 m
1.50 m
Total equivalent length of fittings
Length of measured run
12.51 m
22.00 m
Length of equivalent run
34.51 m
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Answer Key
Assignment 5-5…/continued
Proof G-D:
2-2½ inches 90
1-2½ inches T
3-1¼ inch 90
1-1¼ inch T
1-1¼ inch valve
@ 0.75 m
@ 2.82 m
@ 0.42 m
@ 1.58 m
@ 1.05 m
=
=
=
=
=
1.50 m
2.82 m
1.26 m
1.58 m
1.05 m
Total equivalent length of fittings
Length of measured run
8.21 m
25.00 m
Length of equivalent run
33.21 m
The longest LER of this piping system is 41.03 m. Therefore,
the 45 m CZ is OK.
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Answer Key
Assignment 5-6
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Answer Key
Assignment 5-6…/continued
Step 1: Sizing the low-pressure system
Table:
Propane
Copper tubing
11 inches w.c. with 1 inch w.c. allowable
pressure drop
Table is B.1(a)
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Answer Key
Assignment 5-6…/continued
Loads:
Line A
Line B
Line C
LMR =
CZ
175 Mbtu/h
45 Mbtu/h
220 Mbtu/h
35+ 15+ 10 = 60
= 60
Load (MBtu/h)
Size=A=7/8 inch
B =½ inch
C=7/8 inch
175
45
220
Max. Load (MBtu/h)
236
47
236
Copyright © Canadian Standards Association
Answer Key
Assignment 5-6…/continued
Step 2: Calculate high-pressure zone
Table:
Propane
Copper tubing
10 psig with 5 psig allowable pressure drop
Table is B.4(a)
Calculate load:
Line D
=
LMR
=
CZ
=
220 MBtu/h
70
70
Load (MBtu/h) Max. Load (MBtu/h)
Size of Line D
3/8 inch
220
414
Copyright © Canadian Standards Association
Unit 6
Purging Operations on Large
Piping Systems
Purpose
The methods used to purge large diameter
piping are somewhat different to those used to
purge small diameter piping. This is due to the
large air gas volumes involved, as well as the
greater chance of pipe wall rupture if there is
an ignition and explosion. The gas technician
must be aware that the use of inert gases to
purge large lines removes the posibility of
accidental ignition and explosion.
Copyright © Canadian Standards Association
Unit 6
Purging Operations on Large
Piping Systems
Learning objectives
1. Describe the Code requirements.
2. Explain the safety reasons for purging.
3. Describe the types of purging.
Copyright © Canadian Standards Association
Review code requirements
 Codes concerned with piping and
tubing systems and hose after leak
testing
 Codes referring to gas mixtures to
be used for purging other than for
leak testing
 Specific recommendations
Module 10
Unit 6
Topic 1
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Safety reasons for purging
 Fire and explosion outside pipe
 Fire and explosion inside pipe
Module 10
Unit 6
Topic 2
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Types of purging
 Two purges in succession
 Slug purging
Module 10
Unit 6
Topic 3
Copyright © Canadian Standards Association
Answer Key
Assignment 6
1. With what would you purge a pipe sized over 4 inches, if
it has been tested with air?
 Carbon dioxide or nitrogen or a mixture of both
Copyright © Canadian Standards Association
Answer Key
Assignment 6
2. What conditions occur when purging is not carried out
correctly?
 The accidental explosion of a gas–air mixture outside and
inside the pipe.
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Answer Key
Assignment 6
3. Is it acceptable to purge a new gas line through the
burner system into a combustion chamber?
 No
Copyright © Canadian Standards Association
Answer Key
Assignment 6
4. Why is it important to purge the air out of larger diameter
pipes with an inert gas prior to the fuel gas being
introduced into the pipe?
 So there will be no air in the pipe to support combustion
Copyright © Canadian Standards Association
Answer Key
Assignment 6
5. What is an alternative to completely purging long, large
pipes with nitrogen?
 Slug-purging
Copyright © Canadian Standards Association
Answer Key
Assignment 6
6. What is normal purge velocity for large pipes?
 200 ft/min