Ch 4 Related Science Flashcards
List List five characteristics that are exhibited by a metal.
- Solid at room temperature
- Opaque
- Conductor of heat and electricity
- Reflective when polished
- Expands when heated
____ is a metal sometimes used by journey workers which is liquid at room temperature.
Mercury
What is the base from which most synthetic piping materials are manufactured?
Petroleum/Petrochemical
List three alloys from which pipe is made.
- Stainless steel
- Silicon iron
- Brass
PVC and CPVC pipe are inherently immune to ____ or ____ action.
galvanic or electrolytic
List three methods of joining PVC and CPVC piping materials.
- Solvent cementing
- Threading
- Flanging
What is the difference between cure time and set time as it relates to plastic piping materials?
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.
Relative humidity, temperature and pipe size must be taken in consideration in determining the exact
amount of ____ time for a plastic pipe joint.
cure
Fiberglass reinforced polyester (FRP) is a ____ piping material.
thermoset
List four methods which can be used to compensate for expansion and contraction of PVC and CPVC
piping materials.
- Expansion loops which consist of pipe and 90° elbows
- Piston type expansion joints
- Flexible bends
- Bellows and rubber expansion joints
PVC and CPVC pipe have a high thermal conductivity of heat factor.
False
In practice, all metals are considered to be elements.
False
Most synthetic piping materials are of the thermoplastic type.
True
List the Celsius and Fahrenheit temperature for the melting points of Lead
327°C, 621°F
List the Celsius and Fahrenheit temperature for the melting points of Copper
1,083°C, 1,981°F
List the Celsius and Fahrenheit temperature for the melting points of Iron
1,530°C, 2,795°F
In the expansion of liquids, you are concerned only with their increase in ____.
volume
Describe the purpose of expansion bends and expansion joints in a piping system.
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.
What will happen to the pressure in a hot-water heating system if the compression tank becomes
waterlogged?
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.
T or F: The coefficient of linear expansion is the increase in unit length of a solid for one
degree increase in temperature.
T
T or F: Bimetal strips can be used as controlling devices.
T
T or F: The melting point of steel is nearly the same as that of iron.
T
What is meant by the term ductility of a metal?
Ductility is the ability of a metal to be stretched or drawn thin without cracking or breaking.
____ strength is the resistance of a metal being cut (sheared off).
Shear
The safe shearing stress for steel is ____ to __13,000__ psi.
6,000 to 13,000
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.
solder joint
What is the principle on which the operation of an electric resistance pyrometer is based on?
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.
What is the principle on which the operation of an electric resistance pyrometer is based on?
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.
____ strength is the amount of force required to pull a metal apart.
Tensile
What are three desirable characteristics of 95-5 tin/antimony solder?
- High shear strength
- Does not contain lead
- Can be used on potable water systems
List five mechanical properties of mild steel pipe.
- High ductility — can be stretched
- Malleable — can be bent or hammered into a different shape
- Not brittle — resists cracking
- High tensile strength — resists being pulled apart
- Medium compressive strength — can be crushed
List five mechanical properties of mild steel pipe.
- High ductility — can be stretched
- Malleable — can be bent or hammered into a different shape
- Not brittle — resists cracking
- High tensile strength — resists being pulled apart
- Medium compressive strength — can be crushed
List five mechanical properties of gray cast iron.
- Low ductility — resists stretching
- Not malleable — cannot be bent
- Brittle — cracks easily
- Low tensile strength — pulls apart
- High compressive strength — resists crushing
T or F: Copper tube cannot be hardened on the job.
T
T or F: Zinc and copper can be alloyed to form brass.
T
