Section One Pipe Data

Question 1

What does NPS stand for?

Answer 1

Nominal Pipe Size — a standard designation for pipe diameter, not the actual outside diameter (OD).

Question 2

Does NPS equal the actual OD for all pipe sizes?

Answer 2

No. For pipe sizes under 12”, the OD is larger than the nominal size

Question 3

What does schedule number indicate?

Answer 3

Wall thickness — higher schedule = thicker wall = higher pressure rating.

Question 4

What are the three common wall designations used before schedules were standardized?

Answer 4

Standard (STD), Extra Strong (XS), and Double Extra Strong (XXS).

Question 5

What schedule is equivalent to Standard Weight (STD) up to 10”?

Answer 5

Schedule 40.

Question 6

What schedule is equivalent to Extra Strong (XS) up to 8”?

Answer 6

Schedule 80.

Question 7

What is the outside diameter (OD) of 2” NPS pipe?

Answer 7

2.375 inches.

Question 8

What is the OD of 1” NPS pipe?

Answer 8

1.315 inches.

Question 9

What is the main difference between A53 and A106 steel pipe?

Answer 9

A53 can be welded or seamless

Question 10

What material spec covers stainless steel pipe?

Answer 10

ASTM A312.

Question 11

What material spec covers copper tube?

Answer 11

ASTM B88.

Question 12

What are the three types of copper tubing under ASTM B88?

Answer 12

Type K (thickest), Type L (medium), Type M (thinnest).

Question 13

Which pipe type is commonly used for high-temperature steam?

Answer 13

ASTM A106 seamless carbon steel.

Question 14

What is the joining method for small-diameter steel pipe (2” and under)?

Answer 14

Threaded (NPT) connections.

Question 15

What is the joining method for larger-diameter steel pipe (over 2”)?

Answer 15

Welded or flanged connections.

Question 16

What does a beveled end indicate?

Answer 16

Pipe prepared for welding.

Question 17

What is a grooved end pipe used for?

Answer 17

Mechanical couplings such as Victaulic systems.

Question 18

How does increasing schedule affect pipe ID?

Answer 18

It decreases ID (the hole gets smaller) while OD stays the same.

Question 19

Why is pipe weight per foot important?

Answer 19

For load calculations, rigging, and estimating material weight.

Question 20

What is the formula for the approximate weight of steel pipe per foot?

Answer 20

(OD – Wall Thickness) × Wall Thickness × 10.69.

Question 21

What does A53 Gr B mean?

Answer 21

ASTM A53 Grade B — a stronger grade of carbon steel than Grade A.

Question 22

What marking information must be on a pipe?

Answer 22

Manufacturer, size, schedule, material, and specification (e.g., A106B Sch 80).

Question 23

What does seamless mean?

Answer 23

The pipe is formed without a welded seam, stronger and used for high pressure.

Question 24

What does ERW stand for?

Answer 24

Electric Resistance Welded — a type of welded steel pipe.

Question 25

What happens to the pressure rating as wall thickness increases?

Answer 25

Pressure rating increases.

Question 26

What is the relationship between pipe temperature and expansion?

Answer 26

As temperature increases, pipe length expands.

Question 27

Which material expands more with heat — copper or steel?

Answer 27

Copper expands more.

Question 28

What are typical color codes used for piping identification?

Answer 28

Steam = white, Water = green, Gas = yellow (check local standards).

Question 29

What unit is used to express the weight of pipe?

Answer 29

Pounds per foot (lb/ft).

Question 30

Why is it important to understand OD and ID relationships?

Answer 30

For accurate fitting selection, flow calculations, and layout measurements.