Section Eight Pipe Layout

Question 1

There are two basic fitting types that are used in the installation of a butt welded piping system. These two categories of fittings can be classified as either:

Answer 1

Factory manufactured fittings.

Job fabricated fittings.

Question 2

In what circumstances are job fabricated fittings used?

Answer 2

Where achieving the same results with a manufactured fitting is difficult or impossible.

Question 3

The two methods of laying out pipe for making job fabricated fittings are:

Answer 3

Template development.

Direct pipe way out.

Question 4

Describe the template development method.

Answer 4

A full sized drawing or template is developed for the required fabricated shape. The template is wrapped around the pipe and the pattern is traced on the pipe surface. The pipe is then cut, usually with an Oxy-acetylene torch, following the scribe marks produced by tracing the template.

Question 5

Describe the direct layout method.

Answer 5

The pattern for the fabricated fitting is drawn directly on the pipe from which the fitting is to be made.

Question 6

What are odd angle elbows and why would they be used?

Answer 6

Some job situations require welded elbow angles that are not available. Required elbow may be cut from a standard stock elbow.

Question 7

Establishing centrelines on pipes can be done using two methods what are they?

Answer 7

Square and level.

Plumbob and tape measure.

Question 8

Describe the square and level method for establishing centerlines on pipe.

Answer 8

Using a square and level the insides of the square is butt up against the top and side of the pipe. the level is used for accuracy. Measuring from the inside of the square and across the pipe and dividing the measurement in half will tell you where centre is.

Question 9

Describe the plumbob and tape measure method for establishing centerlines on pipe.

Answer 9

A tape measure is placed across the horizontal center section of the pipe and a plumbob is positioned over the top of the pipe. The plumbob is positioned at half the measurement on the tape and the pipe is then marked on the top and bottom.

Question 10

How would you extend straight lines on the pipe?

Answer 10

By securely fixing an angle iron to the pipe and drawing along the straight edge

Question 11

When using a wrap-around how many wraps should you have on the pipe?

Answer 11

Must overlap at least 1/4.

1-1/4 wraps.

Question 12

How would sectoring a pipe with a tape measure be done?

Answer 12

Either multiply the diameter by 3.14 or wrap the tape measure around the pipe to get the circumference and divide your answer by the amount of sectors needed.

Question 13

Mitered turns – two piece. In order to fabricate a simple two-piece miter turn, the following information is needed:

Answer 13

1. Cut angle of miter.
2. Factor of the cut angle.
3. Cut back distance.

Question 14

Miter turn: What is the cut angle of a miter?

Answer 14

The angle to which each piece of pipe in the turn must be cut. For a two-piece miter turn, the cut angle can be found by dividing the angle of the turn by two.

Question 15

Miter turns: What is the factor of the cut angle?

Answer 15

Factor numbers are used in the miter calculations for determining the cutback distance of the miter turn.

Question 16

Miter turns: what is the cut back distance?

Answer 16

The distance on each side of the centerline to start and end the miter cut. Cut back distance is determined by multiplying the pipe outside diameter times the factor of the cut angle and dividing by two.

Question 17

Multi piece 90° miter turns. There are four pieces of information needed to fabricate these fittings.

Answer 17

1) Cut angle of miter.
2) Factor of the cut angle.
3) Cut back distance.
4) Length of sectional pieces.

Question 18

What is required for large diameter pipe cut lines?

Answer 18

Additional divisional and ordinate lines for accuracy.

Question 19

For larger diameter pipe cut lines there are four examples of the recommended amount of divisions what are the pipe sizes and what are the number of divisional lines?

Answer 19

4”/4
10”/8
24”/16
42”/32