Objective 05: Metal Selection for Process Plant Applications

Question 1

What are the 5 minimum required descriptions that ANSI requires manufacturers to identify pipes, fittings, and flanges with?

Answer 1

1. Size
2. Wall Thickness
3. Schedule Designation
4. Material Type
5. Manufacturer’s Identity Stamp

Question 2

What measurement does Size refer to when it comes to piping?

Answer 2

NPS in inches or DN in mm

Question 3

NPS

Answer 3

Nominal Pipe Size of the nominal outside pipe diameter or the inside flange diameter

Question 4

Wall Thickness

Answer 4

The thickness of piping, steel plate, vessel walls, and pipe fittings, in inches or mm

Question 5

Schedule

Answer 5

The thickness of a pipe or fitting based on standard criteria

Question 6

What does the magnitude of the Schedule number indicate?

Answer 6

The greater the schedule number, the thicker the material, and the greater its ability to withstand internal pressure, corrosion, or erosion

Question 7

Why can the Schedule number always be known for piping?

Answer 7

It is stenciled along the entire length of pipe, to ensure it can be identified when cut into shorter lengths during construction

Question 8

What are the 7 ANSI Schedules that are used to refer to the different pressure rating classes of flanges?

Answer 8

1. 150
2. 300
3. 400
4. 600
5. 900
6. 1500
7. 2500

Question 9

What determines the MAWP of a flange?

Answer 9

Class Number and maximum service temperature

Question 10

What does ASME refer to as Low Temp for piping and fitings?

Answer 10

Limiting design temperature range from -45°C to an upper specified value <425°C

Question 11

What does ASME refer to as High Temp for piping and fittings?

Answer 11

Limiting design temperature range from -29°C to an upper specified value <425°C

Question 12

How is piping/fitting lowest temperature service for either the processing fluid or external environment determined?

Answer 12

Charpy Impact Testing that demonstrates that these metals do not become brittle at these temperatures

Question 13

What are 9 variables that are used to select metal for a pressure piping system?

Answer 13

1. Internal or external maximum pressures
2. Maximum and minimum temperatures
3. Tensile and compressive stress loads
4. Vibration and cyclic stress loads
5. Chemical corrosion exposure
6. Temperature gradients and thermal expansion stress factors
7. Nozzle loading (on flange connections)
8. Impulse stresses (liquid slugging, hydraulic shock, physical collisions)
9. Heat conductivity

Question 14

What must a flange have stamped on it to be acceptable for pressure equipment?

Answer 14

“B16”