Ch 4 Related Science

Question 1

List List five characteristics that are exhibited by a metal.

Answer 1

1. Solid at room temperature
2. Opaque
3. Conductor of heat and electricity
4. Reflective when polished
5. Expands when heated

Question 2

____ is a metal sometimes used by journey workers which is liquid at room temperature.

Answer 2

Mercury

Question 3

What is the base from which most synthetic piping materials are manufactured?

Answer 3

Petroleum/Petrochemical

Question 4

List three alloys from which pipe is made.

Answer 4

1. Stainless steel
2. Silicon iron
3. Brass

Question 5

PVC and CPVC pipe are inherently immune to ____ or ____ action.

Answer 5

galvanic or electrolytic

Question 6

List three methods of joining PVC and CPVC piping materials.

Answer 6

1. Solvent cementing
2. Threading
3. Flanging

Question 7

What is the difference between cure time and set time as it relates to plastic piping materials?

Answer 7

Cure time is the time required before filling and pressurizing a system. Set time is the time required
before moving or handling the assembled joint.

Question 8

Relative humidity, temperature and pipe size must be taken in consideration in determining the exact
amount of ____ time for a plastic pipe joint.

Answer 8

cure

Question 9

Fiberglass reinforced polyester (FRP) is a ____ piping material.

Answer 9

thermoset

Question 10

List four methods which can be used to compensate for expansion and contraction of PVC and CPVC
piping materials.

Answer 10

1. Expansion loops which consist of pipe and 90° elbows
2. Piston type expansion joints
3. Flexible bends
4. Bellows and rubber expansion joints

Question 11

PVC and CPVC pipe have a high thermal conductivity of heat factor.

Answer 11

False

Question 12

In practice, all metals are considered to be elements.

Answer 12

False

Question 13

Most synthetic piping materials are of the thermoplastic type.

Answer 13

True

Question 14

List the Celsius and Fahrenheit temperature for the melting points of Lead

Answer 14

327°C, 621°F

Question 15

List the Celsius and Fahrenheit temperature for the melting points of Copper

Answer 15

1,083°C, 1,981°F

Question 16

List the Celsius and Fahrenheit temperature for the melting points of Iron

Answer 16

1,530°C, 2,795°F

Question 17

In the expansion of liquids, you are concerned only with their increase in ____.

Answer 17

volume

Question 18

Describe the purpose of expansion bends and expansion joints in a piping system.

Answer 18

These devices allow for the expansion of pipes as the temperature of a fluid flowing through the
system increases. Expansion bends and expansion joints absorb the movement of the piping due to
expansion and prevent stresses from being placed on fittings, valves, etc.

Question 19

What will happen to the pressure in a hot-water heating system if the compression tank becomes
waterlogged?

Answer 19

The system pressure will increase rapidly, which could cause the relief valve to discharge because
there is no air space remaining inside the compression tank to allow for water expansion, due to the
increased pressure.

Question 20

T or F: The coefficient of linear expansion is the increase in unit length of a solid for one
degree increase in temperature.

Answer 20

T

Question 21

T or F: Bimetal strips can be used as controlling devices.

Answer 21

T

Question 22

T or F: The melting point of steel is nearly the same as that of iron.

Answer 22

T

Question 23

What is meant by the term ductility of a metal?

Answer 23

Ductility is the ability of a metal to be stretched or drawn thin without cracking or breaking.

Question 24

____ strength is the resistance of a metal being cut (sheared off).

Answer 24

Shear

Question 25

The safe shearing stress for steel is ____ to __13,000__ psi.

Answer 25

6,000 to 13,000

Question 26

A properly made ____ which has blown apart will have solder adhering to both the inside
of the cup of a fitting and the outside of the copper tube.

Answer 26

solder joint

Question 27

What is the principle on which the operation of an electric resistance pyrometer is based on?

Answer 27

Operation of an electric resistance pyrometer is based on the principle that resistance to flow of an
electric current increases as the temperature of the conducting wire increases.

Question 28

What is the principle on which the operation of an electric resistance pyrometer is based on?

Answer 28

Operation of an electric resistance pyrometer is based on the principle that resistance to flow of an
electric current increases as the temperature of the conducting wire increases.

Question 29

____ strength is the amount of force required to pull a metal apart.

Answer 29

Tensile

Question 30

What are three desirable characteristics of 95-5 tin/antimony solder?

Answer 30

1. High shear strength
2. Does not contain lead
3. Can be used on potable water systems

Question 31

List five mechanical properties of mild steel pipe.

Answer 31

1. High ductility — can be stretched
2. Malleable — can be bent or hammered into a different shape
3. Not brittle — resists cracking
4. High tensile strength — resists being pulled apart
5. Medium compressive strength — can be crushed

Question 32

List five mechanical properties of mild steel pipe.

Answer 32

1. High ductility — can be stretched
2. Malleable — can be bent or hammered into a different shape
3. Not brittle — resists cracking
4. High tensile strength — resists being pulled apart
5. Medium compressive strength — can be crushed

Question 33

List five mechanical properties of gray cast iron.

Answer 33

1. Low ductility — resists stretching
2. Not malleable — cannot be bent
3. Brittle — cracks easily
4. Low tensile strength — pulls apart
5. High compressive strength — resists crushing

Question 34

T or F: Copper tube cannot be hardened on the job.

Answer 34

T

Question 35

T or F: Zinc and copper can be alloyed to form brass.

Answer 35

T