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Menu Options
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Electricity: ABB
Watts = Volts x Amps
1 HP (motor) = .746 KW (operating energy)
5 HP x .746 KW/HP x 3413 BTUH/KW = 12,700 BTUH = 1 Ton of Cooling
KW (3 phase) = Volts x Amps x 1.732 x Power Factor/1000
KW (1 phase) = Volts x Amps x Power Factor/10000
Efficiency = 746 x Output Horsepower (HP)/Input Watts
HP (3 phase) = Volts x Amps x 1.732 x Eff. x Power Factor/746
HP (1 phase) = Volts x Amps x Eff. X Power Factor/746 |
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Heating: Cambridge Engineering
Air Change Rate per Hour: Total Volume x ACH/60 = CFM
Air Change Frequency in Minutes: Total Volume/AC Frequency in Minutes = CFM
Heating Load = 24 BTUH/sq. ft. Insulated Building
Heating Load = 40 BTUH/sq. ft. Non-Insulated Building
Combustion Air: 4 CFM OA/1,000 BTUH input
Gas Pressure: 1 PSI = 28” WC (water column) = 2.04” Hg (Mercury) |
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Fuel Comparisons
Natural Gas 1,000,000 BTUH = 10 Therms or 1000 Cubic Ft.
Propane Gas 1,000,000 BTUH = 46 Lb. or 10.88 Gallons
No 2 Fuel Oil 1,000,000 BTUH = 7.14 Gallons
Electricity 1,000,000 BTUH = 293 KW |
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Humidification: Carel
1 lb water = 7000 grains
Self Generating Steam Electrode type
In-duct or Space Atomizing type |
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Fans: Acme, Breidert , Howden, Joy, Loren Cook
Law #1: CFM varies Directly with RPM
Law #2: Static Pressure varies with the Square of the RPM
Law #3: Horsepower varies with the Cube of the RPM
Class 1 Fans: up to 4.5” pressure
Class 2 Fans: up to 7” - 8”: pressure, heavier gauges & larger shafts than Class 1
Class 3 Fans: above 7” - 8” pressure, still heavier gauges & larger shafts than Class 2
Top of curb 8” above roof, common to use 12” high roof curb
Three types: Straight sided, canted and raised cant.
Outside dimension (OD) of curb should be 2” - 3” less than Inside dimension (ID) of equipment sitting on Curb to allow for flashing material to be brought over top
Wood nailer used as means of securing equipment to the curb
Make-up fan inlet shall be at least 10’ away from exhaust fan outlet
Kitchen exhaust duct: welded 16 gauge and shall have velocity over 1500 FPM
Kitchen exhaust hoods: Wall mount: 100 FPM through canopy
Island mount: 150 FPM through canopy
6” overhang on all sides beyond cooking battery
Kitchen exhaust fans shall be upblast and outlet shall be at least 40” above roof g Load = 40 BTUH/sq. ft. Non-Insulated Building
Combustion Air: 4 CFM OA/1,000 BTUH input
Gas Pressure: 1 PSI = 28” WC (water column) = 2.04” Hg (Mercury) |
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CosaTron: ASHRAE
Std. 62.89: 15 CFM OA/Person
Clean Room Design
Class 100,000 .36 air changes/minute, non laminar flow
Class 10,000 1.11 air changes/minute, non laminar flow
Class 1,000 3.00 air changes/minute, non laminar flow
Class 100 4.25 air changes/minute, non laminar flow
Class 10 10.00 air changes/minute, non laminar flow
Class 1 1 - .3 micron size particle/1 cubic foot |
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Swimming Pool Design: Dectron
Must determine evaporation rate: What water temp & air temp?
Norm: 80° pool water temp & 82° air temperature
4 - 6 air changes per hour for pools + 2 additional air changes for pools with spectator facilities
.5 CFM of outside air (OA)/sq. ft. pool and deck area or 15 CFM/person of OA, whichever is greater
Contact factory rep when OA requirements greater than 15% of unit CFM
Must have means of heat rejection for summertime usage, i.e. air cooled condenser
Maintain pool at .05 to .15 negative pressure with exhaust fan and try to place exhaust grille directly over whirlpool
Supply air should be blown across full width of all windows
Do not direct supply air over pool surface
Return air grille 10-15 feet above pool floor level as far away from any whirlpools as possible
Need separate plastic, inline pump for pool water to be circulated through dehumidifier for pool heating
Vapor barrier on warm (inside) portion of outside wall and ceiling
Pool water must be maintained at pH level between 7.2 and 7.6
Do not store pool chemicals in mechanical room
Skylights not recommended
Min. 2.5 duct diameters in return of Dectron unit
Min. 2.5 duct diameters off discharge of Dectron unit
Need 2 - 3 CFM/sq. ft. for glass to minimize glass condensation |
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Air Conditioing: Addison
12,000 BTUH = 1 ton of cooling
1 MBH = 1000 BTUH
Sensible Heat: Measured in dry bulb temperatures
Sensible Cooling/Heating (BTUH) = CFM x 1.08 x Temp Difference
Latent Heat: Measure in wet bulb temperatures and related to change in humidity ratio
Total Cooling (BTUH) = CFM x 4.5 x Enthalpy Difference
Total Cooling = Sensible Cooling = Latent Cooling |
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Insul-Pipe Systems: Water
Cooling (BTUH) = GPM x 500 x Temperature Difference
Pump BHP = GPM x FT x Specific Gravity/3960 x Pump Efficiency
Pump BHP = GPM x PSI x Specific Gravity/1713 x Pump Efficiency
Head in Feet = 2.31 PSIG |
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Replacement Thru-the-Wall Chassis: IslandAire
Designed for American Standard Type 45, Type 41
Remington/Singer Models EA, RS, K, EK and RK
Weil McLain/Freidrich Series 702, 703 and 704
Carrier Series 51 and Zoneaire CSM and CHP
Airtemp, AAF, Climate Master, Fedders, Nesbitt plus others |
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Seismic Guideliness: Mason Industries
Link to PDF |
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Fire Dampers & Louvers: Pottorff
Type A: Return air and transfer air
Type B: Low pressure supply air
Type C: High pressure supply air
All fire dampers are required to have sleeves per NFPA
Static Fire Dampers were tested without air movement in the ductwork.
Dynamic Fire Dampers were tested with air movement. They should be used.
Louver Free Area Velocity = CFM/free area
Normal louver sizing based on 700 FPM through free area of louver |
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Air Distribution: Metal*Aire
1.0 - 1.5 CFM of supply air/sq. ft. of floor area for comfort cooling
Vertical Throw is the maximum distances below the ceiling of the air pattern at terminal velocities of 100, 75 and 50 FPM
Drop is downward supply air movement at a specific throw
Spread is the maximum width of air pattern at terminal velocities of 100, 75 and 50 FPM
Secondary air movement is room air entrained by supply air
700 FPM outlet velocity required for heating out of ceiling diffuser |
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Heat Load
Transmission heat gains: BTUH = “U” factor x sq. ft. x Temperature Difference
Solar heat gains: BTUH = Solar Heat Gain Factor x sq. ft. of glass
People Load: Sensible BTUH = Number of People x 250 BTUH/person
People Load: Latent BTUH = Number of People x 350 BTUH/person
Lighting Load: BTUH = 3 watts/sq. ft. x floor areas (sq. ft.) x 3.413
15,000 BTUH = 1 ton of heat rejection for cooling tower
3.0 GPM/ton for condenser water
Condenser water temperature range: 85° EWT to 95° LWT
Cooling tower water range: 95° EWT to 85° LWT
2.4 GPM/ton for chiller evaporator
Chiller temperature range: 55° EWT to 45° LWT
Chilled water coils temperature range: 45° EWT to 55° LWT |
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Electric Heat: Raywall
1KW = 1000 watts
1KW = 3413 BTUH |
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Sound Attenuators: Vibro-Acoustics
Centrifugal fan noise maximizes in 3rd octave band (250 hz)
Sound power (generation from the fan) and sound pressure (received by the ear) are measured in dB (decibels): Ten (10) times logarithm of the ration of a given power to a reference power. In sound the current reference power is 10-12 watts
NC (Noise Criteria) curves based on different dB levels at different octave bands
With two (2) sound sources of equal dBs, the equivalent dB is the original + 3 dB i.e. 60 dB + 60 dB = 63 dB
With two sound sources of unequal dBs, if the difference is 10dB or more, use higher dB i.e. 70 dB + 60 dB = 70 dB
Sones: a single number method to predict loudness levels, usually for small fans. |
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Refrigerant/Gas Detection Systems: Vulcain
ASHRAE Standard 15-1994 states that a refrigerant monitor must be installed in a refrigerating machinery room
Sampling point should be 18” above finished floor
Sampling point should be positioned between refrigerant system and a room exhaust
Multiple refrigerants can be detected by a singe controller with refrigerant specific sensors |
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Concealed Dampers: Young Regulator
Bowden Cable Control System should be used:
Above Sheetrock ceilings
Above HEPA filter ceilings
Above special architectural ceilings
Above secured prison cells
In underground ductwork
In high atriums
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