FORMULAS, DEFINITIONS, CONVERSIONS

Question 1

1kip

Answer 1

1kip = 1000lbs - unit of force

Question 2

convert square feet to square yards

Answer 2

divide by 9

Question 3

convert Cubic feed to cubic yard

Answer 3

divide by 27

Question 4

1 acre

Answer 4

43560 square feet, and 4840 square yards in 1 acre, (208 feet on each side)

Question 5

tons to pounds

Answer 5

1 ton = 2000 pounds

Question 6

1 horsepower

Answer 6

1 horsepower = 2544 BTU/hr,

Question 7

foot lambert to candela candela to lumen

Answer 7

1 FL = 0.3183 candela / sf

1 candela = 12.57 lumens

Question 8

1 PSI how many feet of static head?

Answer 8

1 PSI = 2.31 Feet Of Static Head

10 psi available x 2.31 = 20.31 available height!

Question 9

Allowable max BEAM STRESS - FORMULA

Answer 9

F = M / S

ALLOWABLE BENDING STRESS = MAX.MOMENT / SECTION MODULUS

Question 10

COLUMN SLENDERNESS RATIO

Answer 10

SLENDERNESS RATIO = L / R

L=Length

R = RADIUS OF GYRATION

Question 11

Windload formula

Answer 11

Wind load / sf * area normal to wind = windload

Question 12

Allowable Beam Deflection

Answer 12

The maximum vertical displacement of the member as it bows under loading. These limits vary depending on code requirements, but may be similar to L/180, L/240, L/360, or L/480

A beam spans 20’. How many inches will it be allowed to deflect if required to meet a maximum of L/240?

20’ * 12” = 240” > 240” / 240 = 1” Allowable deflection

Question 13

Modulus of Elasticity of steel

Answer 13

29,000,000 psi

Question 14

area of circle

Answer 14

A = π r²

Question 15

area of sphere

Answer 15

A=4πr²

Question 16

1 kip/in2. = ? psi

Answer 16

1 kip-force/square inch = 1000 psi

Question 17

Pressure P formula

Answer 17

Pressure P is defined as

P=F/A

where F is a force applied to an area A that is perpendicular to the force.

Question 18

actual dimension of 2x4?

Answer 18

1-1/2 x 3-1/2

Question 19

Board-feet

Answer 19

is an approximation of the volume of lumber needed,

measured in nominal dimensions.

A 1x10 that is 8 feet long is 1x10x8’/12=6.7 board-feet.

Question 21

joist notches

boreholes

Answer 21

joist notches cannot exceed 1⁄6 of joist depth and may not be located in the middle third of the beam

boreholes annot exceed 40% of stud depth

Question 22

11 metals in order of Galvanic series, in the presence of sea water from worst to best

Answer 22

Zinc

Aluminum

Steel,

Iron

304 Stainless Steel (Active)

Copper,Bronze,Brass

Tin

Lead

316 Stainless Steel (Active)

Titanium

304 Stainless Steel (Passive)

Gold

zippers allure strangers ironically to 304 active strangers,

Cops timidly Lead 316 active strangers with Tits to 304 passive strangers in gold.

Question 23

1 sack of cement weight? how much water?

Answer 23

4 to 4.5 gallons of water per 94 lb sack of cement

Question 24

Rebar overlap

Answer 24

Rebar overlap is 30x rebar diameter Bottom bars resist bending at midspan, stirrups resist diagonal forces at either end of the beam

Question 25

Temperature at a point in a wall - Formula

Answer 25

T_outside + [(Rvalue outside of point in wall/Rvalue total) x ΔT]

Question 26

1 horsepower?

1 ton of cooling ?

Answer 26

1 horsepower = 2544 BTU/hr,

1 ton of cooling = 12,000 BTU/hr

Question 27

calculate daylighting:

Answer 27

• Measure from bottom of floor to the top of the window (doesn’t matter how big it is)
• You can go 2.5x that length into the building for lighting penetration
• Daylighting Factor

max = 0.2 (window area/floor area)

min = 0.1 (window area/floor area)

• Remember…it should be between 1% - 5%!

Question 30

CFM formula

Answer 30

cfm=(space volume) x ACH / (60 min/hr)

Start with the total volume of air (in cubic feet), divide by the exchange rate (ach/ how quickly you want to replace the air), and the result is the total CFM (cubic feet per minute) you need for your system

Question 31

how many db to decrease sound by half

Answer 31

3db

Question 32

Sound - Inverse square law

Answer 32

intensity of sound at any given point is inversely proportional to the square of the distance from the source of sound

I1 / I2 = R2² / R1²

Question 33

Additions of decibels - Difference 0-1 Db

Answer 33

add 3 db to higher value

Question 34

Additions of decibels - Difference 2-3 Db

Answer 34

add 2 db to higher value

Question 35

Additions of decibels - Difference 4-8 Db

Answer 35

add 1 db to higher value

Question 36

Additions of decibels - Difference 9- or more Db

Answer 36

dd 0 db to higher value

Question 37

Energy CALC

Answer 37

E = P*T

Energy = Power * time

measured in watt hours or kilo watt hours

Question 38

Series circuit

Answer 38

Rtotal = R1 + R2 + R3

Question 39

Parallel circuit

Answer 39

1/ Rtotal = 1/R1 + 1/R2 + 1/R3

Question 40

ohms law mnemonic

Answer 40

Woman Are Virgins

Watt = Amps x Volts

Virgins Are Rare

Volt = Amps x Resistance (ohm)

Question 42

LIGHT: Point source - Surface Perpendicular to source: formula

Answer 42

E = i / d^2

illumination (footcandles) = candle power (candelas) / distance^2 (ft2)

Inverse square law

Question 43

LIGHT: Point source - Surface not Perpendicular to source: formula

Answer 43

E = I*cos Angle / D^2

illumination = candle power* cos Angle / distance^2 (sf)

footcandles= (candelas) * cos Angle / f^2

Question 44

efficacy formula

Answer 44

Efficacy =

(Luminaire Efficiency * Total Lamp Lumens * Ballast Factor) / Total Power Input

Question 45

Typical indoor illuminance

Answer 45

10 to 100 fc

Need at least 1 footcandle at the floor for egress.