misc Flashcards
1
Q
prestressing concrete: pretensioning
A
concrete bonds to prestressed members laid in the formwork
2
Q
prestressing concrete: post-tensioning
A
sleeves are cast into concrete. cables are inserted, tensioned, affixed
3
Q
concrete decks: 1:2 or greater
A
one-way span
4
Q
slabs and beams transmit load in
A
bending
5
Q
columns and bearing walls transmit load in
A
compression
6
Q
buildings add how many degrees to the degree day temperature
A
5
7
Q
BTU raised the temp of 1 lb of water
A
1 degree F
8
Q
H-value or conductivity
A
of BTUs per hour that pass through 1” thick material
9
Q
C-value or conductance
A
for material more than 1” thick
10
Q
R-Value or resistance
A
of hours needed for 1 U to pass through material of a given thickness when the temp is 1 degree F different
11
Q
1 ton of hvac capacity = how many BTUs
A
12,000 BTUs
12
Q
1 ton of HVAC capacity =
A
1 ton of ice into water per day
13
Q
(HVAC) Boots
A
chance the direction / shape of a duct
14
Q
(HVAC) register
A
delivery end of a duct on walls and floors
15
Q
(hvac) grilles
A
registers without operable fins (wall and floor delivery)
16
Q
(hvac) diffuser
A
delivery end of a duct from above
17
Q
throw of a register
A
3/4 depth of the space
18
Q
spacing of a register
A
1/3 of the throw
19
Q
percentage of the building taken up by mechanical systems
A
3 - 10%
20
Q
ASHRAE
A
heating, refrigeration, a/c engineering
21
Q
ashrae 55
A
thermal comfort for human occupancy
22
Q
ashrae 62.1
A
ventilation for IAQ (residential)
23
Q
ashrae 90.1
A
energy standard for commercial buildings (envelope, hvac, hot water, electrical power, lighting, other)
24
Q
voltage
A
movement of electrons due to a difference in positive and negative charge encouraging the flow of electrons
25
amperage
the speed at which electrons are traveling, how many electrons are traveling over a period of time
26
3.413 BTU / hour =
1 watt
27
746 watts =
1 hp
28
watts =
volts x amps
29
car battery that is 12 volts connected to 300 amp jumper cables can deliver how many watts?
3600 watts
30
residential electrical delivery (standard)
single phase, 3-wire
0 / 120 / 120
31
commercial electrical delivery (standard)
3-phase, 4-wire
0 / 120 / 120 / 120
32
power equals
wattage available
33
energy equals
use of power over time
34
solar operates on a/c or d/c
d/c
35
how much energy is lost stepping down a/c vs d/c
a/c: 1 - 2% in conversion
d/c: approx 25% in conversion
36
3-phase systems have all 3 wires of of phase. what level of voltage will this system deliver on average
208 volts
37
industrial / large scale energy delivery
277/480 volt 3-phase, 4-wire
38
common amperage allowance for small buildings?
100 amps
39
120 volt, 100-amp system - how many watts available?
12000 watts (12 kw)
40
3-phase power
360 volt, 400-amp system - how many watts available?
144000 watts (144 kw)
41
always on devices need what percentage of their stated power available
125%
42
watts of these everyday items
ceiling fan
hair dryer
computer
water heater
65-175 watts
1200-1875 watts
120 watts
5000 watts
43
what is romex
plastic shielding used in smaller/residential projects instead of metal conduit
44
wires: AWG classification
8 gage or smaller (higher gage)
45
cables: AWG classification
6 gage or larger (lower gage)
46
smallest wire allowed for electrical service
14 awg (copper)
47
Largest awg?
0000 (1/2" thick)
48
cables larger than 0000 awg measured in?
mcm. 2000 mcm largest used in construction (1.5")
49
voltage =
amperage x resistance (1 volt = 1 amp x 1 ohm)
50
EMT
electrical metallic tubing - common type of conduit
51
rigid metal conduits
bigger, thicker than EMT
52
low voltage types which need to be shielded from higher voltage wires
cat 3 - telephone
cat 5 - internet
often contained in cable trays
53
1 PSI of force lifts water
2.3' (2' - 4")
54
how much PSI required to lift water 1'?
0.433 PSI
55
Copper piping classifications
K - L - M thick to thin
56
which is the only copper pipe OK for underground use?
K
57
plastic piping types ok for cold water
PB, PE, PVC, CPVC, PEX
58
plastic piping types ok for hot water
PB, CPVC, PEX
59
pinned connections resist:
forces in x + y, not moment
60
roller connections resist:
forces in y only
61
fixed connections resist
forces in x + y and moment
62
the sum of the moments equals
0
63
in order to solve for moment, you must choose a support that resists
moment - fixed connections only
64
equilibrium formula for solving moments
distance (force) + distance (force) = 0
65
trusses puts loads into
purely tensile and compressive forces
66
Portland cement: type I
general purpose
67
Portland cement: type II
moderate (less heat generated, cures slower, good for warm weather). good for high sulfates like found in groundwater
68
Portland cement: type III
high early strength. good in cold climates
69
Portland cement: type IV
for significant structures like dams
70
Portland cement: type V
high sulfate resistance
71
types of hydrated lime
N (normal) S (special - more water, more workability)
72
metal forming: extruding
pushed metal through a die
73
metal forming: drawing
pulls metal through a die
74
metal forming: rolling
passes metal over rollers
75
metal forming: casting
poured molten metal
76
air entrained concrete benefits:
higher workability, lower water, improved durability, good for freeze/thaw
77
ionization detectors
detect fire at the earliest (incipient) stages (no visible flame or smoke)
78
Photoelectric sensor detectors
detect smoke and smoldering pre-flame (scattered light and laser beam)
79
flame detectors
detect flames
80
heat stage detectors
rise in temp detectors, flames tend to need to be present
81
low strength or high strength mortar: more water tight
low strength
82
low strength or high strength mortar: for seismic areas
high strength
83
footcandles (fc) =
Cp / d squared (candlepower over distance squared
84
globe valves
stop, start, and regulate
85
gate valves
stop and start, no regulation
86
check valves
prevent backflow
87
ball valves
stop and start, no regulation
88
change in length (due to deflection) =
force x length / area x modulus of elasticity
89
masonry wall coatings: 2 categories
film formers (urethane-based, acrylic, mineral gum waxes) and penetrants (silicates and silicone rubber)
90
steps of finishing poured concrete slabs
screeding/striking off (uses a 2x4 to level finish), floating (uses a float to level further), troweling (metal trowel is further smoothing needed)
91
elastic vs plastic
elastic materials return to their original shape when load is removed (elastic materials are brittle). plastic materials deform when load is removed (ductile materials are plastic). concrete is brittle, steel is ductile. elastic materials carry load to their yield point, plastic materials carry load beyond their yield point
92
glass types: annealed
standard glass
93
glass types: heat strengthened
good for thermal changes, good for spandrel glass, less distortion than tempered, breaks like annnealed
94
glass types: tempered
shatters into tiny rocks. 2x stronger than heat stregthened
95
glass types: heat soaked
strongest glass, most expensive
96
levels of glass insulation
monolithic glass: r-1
IGU with single air space: r-2
igu with single air space, low-e: r-3
same as above but argon filled: r-4
97
wattage
measure of electrical power
98
current:
electrical resistance in amps (I)
99
resistance
frictional loss (ohms) (R)
100
voltage
electrical flow between positive and negative (v = current (I) x resistance (R))
101
galvanic action, cathodic (most noble) to anodic (least noble)
platinum, gold, silver, stainless, brass, chromium, nickel, copper, cast iron, steel, lead, tin, aluminum, galvanized, zinc, magnesium
102
open web joists: shortest span (cheapest) to longest span (most expensive)
k - lh - dlh
103
nails: casing
window frames, trim. small head countersinks
104
nails: common
thick shank, used for framing
105
nails: box
thinner for shingles and siding (reduced splitting)
106
nails: sinker
tapered head to sit flush
107
nails: duplex
double head for temporary uses like scaffolding and formwork
108
nails: finish
for fine carpentry
109
nails: ring shank
for floor sheathing and gypsum wallboard
110
nails: roofing
large head
