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Furnace Commisioning > Gas Pipe > Flashcards

Gas Pipe Flashcards

1
Q

Most common type of material used in gas piping

A

Black iron

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2
Q

What is schedule

A

The manufacturers Gauge of metal thickness, lower the number the lighter the gauge

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3
Q

What changes when you change schedule pipe

A

The inside diameter

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4
Q

The recommended rate for tightening is?

A

1/4 per revolution

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5
Q

What is the largest diameter pipe you can thread

A

2”

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6
Q

What is a nipple

A

A short piece of pipe with a thread on each end comes in the schedules

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7
Q

Are close nipples allowed to be used on gas lines, why or why not

A

They are not permitted for use on natural gas or propane. No orginal wall thickness.

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8
Q

What makes the seal on gas pipe

A

A taper thread, then tape or dope

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9
Q

What are tape and dope considered

A

A lubricant.

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10
Q

What is centerline angle what is included angle

A

Center line is 30° included is 60°

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11
Q

Recommended # of thread per inch of thread for ½ and ¾ and approx number of threads to cuts to obtain standard thread

A

14 threads and 10 ½

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12
Q

What happens if you don’t remove the bur from cutting

A

Can cause pressure loss, turbulence, and the possibility of catching foreign material

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13
Q

Order of cutting threads

A

Measure, cut, ream, then thread

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14
Q

Hand tight thread engagement and wrench tight

A

4¾ threads hand tight first than 3 threads wrench

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15
Q

Can power drives use spiral reamers?

A

No, they dig into aggressively

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16
Q

When should cutting oil be applied to pipe and threading equipment? How much?

A

It should be applied during the threading process.

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17
Q

How much cutting oil should be used? And why?

A

A generous amount, it’s the beat safeguard against poor threads, excessive die wear, clearing debris build up and heat

18
Q

When should you stop threading?

A

When the outer surface or faces of the dies are flush with the end of the pipe or follow die manufacturers recommendations.

19
Q

If you continue to thread beyond the stopping point what will happen. Why is it important to stop

A

You will make a straight or running thread in addition to the taper. Proper thread length is essential in forming leak proof joints

20
Q

Black iron is referred to as? Why?

A

Malleable iron, it’s a cast iron that has been heat treated to render it less brittle.

21
Q

What are elbows used for? What is an elbow that changes from one size to another called

A

They are used to change directions come in 90° and 45°. A reducing elbow

22
Q

An elbow with thread on one side is called? Can it be used in gas connections?

A

Code states that this kind of elbow can not be used in any gas connections you will make.

23
Q

What are bushings used for

A

Bushings are sometimes supplied with gas valves to reduce one gas size to another.

24
Q

Can you use face bushings?

A

No, same reason you can’t use close nipples

25
Q

What does nesting bushings mean.

A

Using multiple bushes to reduce down multiple sizes

26
Q

Pipe compound must be applied to the… and why

A

Male end, so any excess dope is forced out the pipe instead of being pushed into it.

27
Q

How to apply Teflon tape?

A

Must be applied by wrapping it clockwise, stretching it with a 50% overlap, and leaving the first 2 starter thread bare.

28
Q

What part of the pipe wrench should and should contract fitting when tightening

A

Two points of contact the hook jaw shouldn’t touch

29
Q

What is type k copper

A

Type K is the thickest wall of copper, available in ¼ to 12”

30
Q

What is type L copper and it’s color code

A

Medium wall thickness, availed in the same nps, tempers and lengths as type K. Blue color code

31
Q

What is type M copper and it’s color code

A

Type M is lighter walled copper, used for water lines and can’t be bent. Color code red

32
Q

What is type G copper

A

Coned in sizes from ⅜ to 1⅛ coil of 25,50 or 100 feet

33
Q

One of the biggest advantages of copper is?

A

Easily formed to fit on the job site for tight installation

34
Q

What is copper pip

A

Have the same wall thickness as iron pipe and come in the same diameter

35
Q

What is copper tube

A

A hard drawn material( braze,flared) that is not flexible

36
Q

What is copper tubing

A

Soft draft material, annealed which makes it flexible and comes in coil lengths

37
Q

What other kind of tubing can be used

A

Aluminum and CSST( corrugated stainless steel tube)

38
Q

When copper is cut do you need to remove the bur

A

Yes

39
Q

What are the basic designs of flared fittings which is HVAC specific

A

The SAE 37° autootive
The SAE 45° pipetrades aka hvac
and inverted flare

40
Q

Two types of benders

A

Lever and spring tube

Furnace Commisioning (10 decks)

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