Formulas

Question 1

Illuminance / footcandle

Answer 1

E=I/d^2
I or intensity
d or distance

Question 2

Luminance

Answer 2

L=E(R)
E or illuminance
R or reflectance

Question 3

Conduction or Heat Gain

Answer 3

U x A x Delta T

Question 4

Power

Answer 4

P= V x I x PF x sqrt(3)
P or Power in Watts
V or voltage in volts
I or current in amps
PF or power factor

Question 5

U - value

Answer 5

1/R value or

(Ux area of window + U x Area of wall)/total area

Question 6

Q - Ventilation / convection

Answer 6

Q= 1.08 x CFM x Delta T

Question 7

Foot Candles

Answer 7

Foot candles = Lumens/ Area in Ft2
or
(Lamp Lumens) x Lumens per Fixture x number of fixtures x CU x LLF / Area

Question 8

Building Loss Coefficient

Answer 8

BLC = UAenvelope + UAinfiltration

Question 9

1 ACH/ HR

Answer 9

63.2% new air in room

Question 10

1 PSI

Answer 10

2.31 feet of water ( 1 PSI will raise water 2.31 feet vertically)

Question 11

Thermal Expansion

Answer 11

Length x Coefficient of Expansion x Delta T

Question 12

1 Watt

Answer 12

3.41 BTU/hour

Question 13

1 ton of AC

Answer 13

12,000 BTU/hr

Question 14

1kwh

Answer 14

3,400 BTU/hr

Question 15

Cross section area of a duct

Answer 15

144x(the flow rate in CFM)/ velocity measured in feet per min (V)

Question 16

Ohms Law

Answer 16

I=V/R
I or current in amps
V or voltage in volts
R or Resistance

Question 17

Number of Luminaires

Answer 17

footcandles x floor area/ lumens x CU x LLF

Question 18

Coefficient of Clear Glass

Answer 18

85%

Question 19

Coefficient of Frosted Glass

Answer 19

70-85%

Question 20

Contrast ratio of task to adjacent surface

Answer 20

1:1/3

Question 21

Contrast ratio to dark surfaces

Answer 21

1:1/5

Question 22

Contrast to lighter surfaces

Answer 22

1:10

Question 23

Daylight factor

Answer 23

0.2 x window area/floor area

Question 24

Wavelength

Answer 24

velocity of sound/frequency of sound

Question 25

Sabins

Answer 25

Surface area of room x absorptivity of surfaces

Question 26

NRC

Answer 26

Total sabins or A/ Total surface area in the room or S

Question 27

Elevator Speed

Answer 27

1.6 x building height + 350

Question 28

1 therm = ___________ Btu

Answer 28

10,000 btu