Building Systems, Materials, & Assemblies

Question 1

What is the internal resistance to an external force?

Answer 1

Stress. (Tension, Compression, Shear, Torsion, Bending, Combined Stresses)

Stress f = total force P / total area A

Question 2

What are the three basic types of stress?

Answer 2

Tension, compression, and shear

Question 3

What is tension?

Answer 3

Tension is stress in which the particles of the member tend to pull a part under load.

Question 4

What is compression?

Answer 4

Compression is stress in which the particles of the member are pushed together and the member tends to shorten.

Question 5

What is shear?

Answer 5

Shear is stress in which the particles of a member slide past one another.

Question 6

Coefficient of Expansion

Answer 6

Thermal Stress

plastic, acrylic = 0.0000450
aluminum = 0.0000128 in/in-F
bronze = 0.0000101
structural steel = 0.0000065
concrete = 0.0000055
glass = 0.0000051
marble = 0.0000045
brick = 0.0000034

Question 7

What is the deformation of a material caused by external forces?

Answer 7

Strain (e)

strain (e) = total strain e / original length L

Question 8

What is Hooke’s law?

Answer 8

As a force is applied to a material, the deformation (strain) is directly proportional to the stress, up to a certain point.

Question 9

Elastic Limit

Answer 9

On a stress-strain graph, the point at which the material will experience deformation faster. (Prior to to this point stress and strain are directly proportional.)

Question 10

Ultimate Strength

Answer 10

The failing point of a given material.

Question 11

Yield Point

Answer 11

On a stress-strain graph, the point at which the material begins to deform with minimal increase in load (stress).

Question 12

Modulus of Elasticity

Answer 12

A stress to strain ratio of a given material. €

Question 13

e = PL/AE

Answer 13

Total strain (deformation) of a material under a given load.

A = total area
P = total force
L = original length
e = total strain

Question 14

Moment

Answer 14

The tendency of a force to cause rotation about a point.

Question 15

Btu

Answer 15

The amount of heat required to raise the temperature of 1 lbm of water 1dF

Question 16

Joule (J)

Answer 16

A measure of energy, one joule is a newton meter, or the force of 1 N acting through a distance of 1 m. One joule is 1/4.184 the amount of heat required to raise one gram of water by 1dC. One Btu equals about 1.055 kJ.

Question 17

Coefficient of heat transmission

Answer 17

The overall rate of eight blow through any combination of materials, including air spaces and air layers on the interior and exterior of a building assembly.

Question 18

Conductance

Answer 18

The number of British thermal units per hour that passes through 1 ft.² of homogeneous material of a given thickness when the temperature differential 1°F.

Question 19

Dew Point

Answer 19

The temperature at which water vapor in the air becomes saturated and begins to condense two drops of water.

Question 20

Dry-bulb temperature

Answer 20

The temperature of the air-water mixture as measured with a standard dry-bulb thermometer.

Question 21

Enthalpy

Answer 21

The total heat in a substance, including latent heat and sensible heat.

Question 22

Latent Heat

Answer 22

Heat that causes a change of state of a substance, such as the heat required to change water into steam. The amount of heat required to change the state of a substance is much greater than the heat required to raise the temperature of the substance (sensible heat).

The average value of latent heat per lb of moisture is 1061 Btu (1120 kJ).

Question 23

Resistance

Answer 23

The number of hours needed for one Btu to pass through one square foot of material or assembly of a given thickness when the temperature differential is 1°F. It is the reciprocal of conductance.

Question 24

Sensible heat

Answer 24

Heat that causes a change in temperature of a substance but not a change of state. For example, the sensible heat required to raise the temperature of 1 lbm of water from 50°F to 100°F is 50 Btu (53 kJ).

Question 25

Specific heat

Answer 25

The number of Btus (joules) required to raise The temperature of a specific material by 1°F. Specific heat is a measure of a material capacity to store heat as compared with the storage capacity of water.

Question 26

Wet-bulb temperature

Answer 26

The temperature of the air as measured with a sling psychrometer. The wetbulb temperature is a more critical measure heat because it is an indicator of stress when the human body is near the upper limit of temperature regulation by perspiration.

Question 27

What are the primary and environmental factors of human comfort?

Answer 27

Temperature, humidity, air movement, temperature radiation to and from surrounding services, air quality, sound, vibration, and light.