Module 5

Question 1

The minimum pressure at which a component begins to split apart

Answer 1

Bursting presssure

Question 2

Bursting pressure divided by system operation pressure

Answer 2

Safety factor

Question 3

Air at normal atmospheric pressure (14.7 psi)

Answer 3

Free air

Question 4

Piping fixture used to trap and eliminate water in the line

Answer 4

Drain leg

Question 5

Measurement of a curve in tubing, from tubing centerline to the center of the circle

Answer 5

Bend radius

Question 6

Name the three types of compressed-air conductors used in a pneumatic piping system.

Answer 6

Pipe
Tubing
Hose

Question 7

Air should flow through a pipe in a(n) _____ pattern.

Answer 7

Streamlined or Laminar

Question 8

The size of an air line should be selected so only a small _____ drop occurs.

Answer 8

Pressure

Question 9

Name at least four items that affect pressure drop.

Answer 9

Volume of air
Air pressure
Length of pipe
Number of fittings
Number of bends

Question 10

To reduce the distance air travels in a large loop system, _____ air receivers are used.

Answer 10

Auxiliary or Extra

Question 11

The lower the pressure in a pipe, the _____ the pressure losses will be.

Answer 11

Larger

Question 12

Pressure losses through fittings and valves are given in terms of _____ of straight pipe.

Answer 12

Feet (or Lengths)

Question 13

Name the three methods used for connecting pipe in a pneumatic system.

Answer 13

Threading
Welding
Flanging

Question 14

Compressor discharge lines should slope away from the compressor at a rate of ______ in. for every _____ ft.

Answer 14

1, 10

Question 15

NPT, when used for pneumatic systems, seals against air leaks with flank-to-flank contact and _____.

Answer 15

Piping compound

Question 16

When connecting pipes, you must never apply piping compound to the _____.

Answer 16

Thread ends

Question 17

More accurate inside and outside diameters are an advantage of _____.

Answer 17

Metallic tubing

Question 18

Avoid using metallic tubing that has been bent and then _____.

Answer 18

Straightened

Question 19

When an air hose is connected to pneumatic piping, the hose should be one size _____ than the size of the connecting pipe thread.

Answer 19

Larger

Question 20

Hose fittings may be classed as permanent and _____.

Answer 20

Reusable

Question 21

The type of hose coupling that uses a spring-loaded poppet to seal off the outlet when the hose is removed is called a(n) _____ coupling.

Answer 21

Quick-disconnect

Question 22

Turbulent airflow is likely to result from a(n) _____.

Answer 22

Large airflow velocity increase.

Question 23

Which type of threaded fitting is probably the best suited to all but heavy-duty air-line applications?

Answer 23

150 lb malleable iron.

Question 24

The pressure drop between the air receiver and the farthest point of air use should be no more than _____ % of the compressor cutout pressure.

Answer 24

10

Question 25

The rate of downward slope for compressed-air piping used for compressor distribution lines should be _____.

Answer 25

1 in. per 10 ft.

Question 26

Excessive pressure drops occurring in a loop system during peak flow may be avoided by the use of auxiliary _____.

Answer 26

Air receivers and compressors.

Question 27

Long pipe runs should always be _____.

Answer 27

Supported with hangers.

Question 28

How does a change in air pressure in a pipe affect the pressure losses?

Answer 28

Decreased pressure, higher losses.

Question 29

Most nonmetallic tubing can be used for a maximum of _____.

Answer 29

100 psi and 190F

Question 30

The pressure loss through fittings and valves is calculated in terms of _____.

Answer 30

Feet of straight pipe.

Question 31

When disconnecting an air hose, make sure to take all of the following precautions except

a. depressurize the hose
b. have a buddy present
c. use the shutoff valve, if there is one
d. wear eye protection

Answer 31

b. Have a buddy present.