HVAC ENGINEERING CHEAT SHEET

CONVERSIONS and CONSTANTS EQUATIONS DUCT SIZING CRITERIA RECOMMENDED VELOCITIES

Energy Heat System pd [in/100ft] Veolcity System FPM

1 Watt = 3.412 BTU/h Q [Kw/h] = Volume (liters) * 4.19 * ΔT [°C] / 3600 M.P. Risers - 2,500 Penthouse Dampers 1,000 - 1,200

1 HP = 746 W Qs [BTU/h] = CFM * 1.08 * ΔT [°F] M.P. Riser Takeoffs - 2,000 - 2,500 Penthouse Louvers 500

1 HP = 2,545 BTU/h M.P. Duct 0.3 2,000 Cooling Coils 550 - 600

1 MBH = 1,000 BTU/h Ql [BTU/h] = CFM * 4840 * Δw [lbw/lba] L.P. & Return Duct 0.1 1,200 Heating Coils 750 - 1000

1 Cooling Ton = 12,000 BTU/h Exhaust Duct 0.1 1,500 Filters 500

1 CFH Nat. Gas = 1 MBH QT [BTU/h] = CFM * 4.5 * Δh [BTU/lb] Grease Exhaust Duct - 2,000 - 2,500 Gravity RA Shaft 500

1 CFM = 0.48 L/S General Pressure Drop 0.06-0.09 2,000 - 2,500 Relief Fan RA Shaft 1000

1 TR = 3.5 KW Q [BTU/h] = ṁ [lb/h] * c [BTU/lb °F] * ΔT [°F] PIPE SIZING CRITERIA Return Fan RA Shaft 1500

Air Pipe Size [in] Max V [fps] GPM (Steel) Drywall Exhaust Shaft 1000

ρair = 0.075 lb/ft3 Q [BTU/h] = GPM * 500 * ΔT [°F] 1/2 3 -

cair = 0.24 BTU/lb°F 3/4 3 5

1 psi = 27.7 in H2O Q [BTU/h] = U [BTU/h ft2 °F] * A [ft2] * ΔT [°F] 1 3 8 VAV SIZING
1 atm = 14.7 psi 1 1/4 4 18 VAV Size Max CFM

Water Horsepower 1 1/2 4 25 6 400

ρwater = 62.4 lb/ft3 2 4 40 8 720

cwater = 1.0 BTU/lb°F CFM * SP [in] 2 1/2 6 90 10 1120

BHPfan =
1 psi = 2.31 ft H2O 6356 * ηfan * ηmotor 3 6 140 12 1600

1 gal = 8.34 lbs 4 8 320 14 2400

1 ft3 = 7.48 gal GPM * Head 5 8 510 16 3200

BHPpump =
1 lb = 7,000 grains 3960 * ηpump * ηmotor 6 10 900 40 (24"x16" Inlet) 4800

8 10 1600
Max Air ∆Ps (2-row): 0.60 in
Misc Cooling Towers 10 12 3000
Max Air ∆Ps (1-row): 0.30 in
U [BTU / h ft2 °F] = 1 / R Rule of Thumb Makeup = 0.05 GPM/TON 12 12 4200

SHGC = SC * 0.87 14 12 5700

kW/ton = 12 / EER Makeup [GPM] = Evap Rate [GPM] + Bleed Rate [GPM]

COP = EER / 3.412 Evap Rate [GPM] = Flow [GPM] * ΔT [°F] * 0.001 Medium Pressure Ductwork Exhaust Ductwork
VP = (V / 4005)2 Bleed Rate [GPM] = Evap Rate [GPM] / (Cycles of Conc. - 1) Max 2,000 FPM & Max 0.3"/100 ft Max 1,500 FPM & Max 0.1"/100 ft

°F = 1.8 °C + 32 Duct Size Max CFM Max CFM Duct Size Max CFM

g = 32.17 ft/s2 Misc 6"Ø 200 110 6"Ø 110

CFM = ACH * Room Volume [ft3] * (1 / 60) [hr/min] 8"Ø 420 230 8"Ø 230

V [fpm] = CFM / A [ft2] 10"Ø 760 420 10"Ø 420

W [watts] = V [volts] * I [amps] * √φ 12"Ø 1,250 680 12"Ø 680

V [volts] = R [resistance] * I [amps] 14"Ø 1,850 1,050 14"Ø 1,050

16"Ø 2,600 1,450 16"Ø 1,450

18"Ø 3,600 2,000 18"Ø 2,000

20"Ø 4,500 2,600 20"Ø 2,600

PSYCHROMETRIC CHART BASICS 22"Ø 5,400 3,200 22"Ø 3,400

12"x12" 1,500 840 12"x12" 840

1. Dry Bulb Temp [°F] A. Humidifying Only 14"x14" 2,250 1,250 14"x14" 1,250

2. Relative Humidity [%] B. Heating & Humidifying 16"x14" 2,600 1,500 16"x14" 1,500

3. Wet Bulb Temp [°F] C. Sensible Heating Only 16"x16" 3,200 1,800 16"x16" 1,800

4. Enthalpy [Btu/lba] D. Chemical Dehumidifying 24"x12" 3,600 2,000 24"x12" 2,000

5. Humidity Ratio [lbw/lba] E. Dehumidifying Only 20"x16" 4,200 2,400 20"x16" 2,400

6. Volume [ft3/lba] F. Cooling & Dehydrating 24"x18" 5,400 3,400 24"x18" 3,400

7. Dew Point [°F] G. Sensible Cooling Only 24"x24" 7,000 4,250 24"x24" 5,000

H. Evaporative Cooling Only 30"x30" 11,500 6,900 30"x30" 8,600

36"x30" 14,000 8,400 36"x30" 10,500

42"x30" 16,000 9,600 42"x30" 12,000

46"x30" 18,000 10,500 46"x30" 13,000

52"x30" 20,000 12,000 52"x30" 15,000

60"x30" 22,500 13,500 60"x30" 17,000

HVAC ENGINEERING CHEAT SHEET

ASHRAE 62.1 VENTILATION TABLE ASHRAE 62.1 VENTILATION TABLE cont. ASHRAE 62.1 EXHAUST TABLE ASHRAE LIGHTING LOADS
People Outdoor
Area Outdoor Air Occupant Density People Outdoor Area Outdoor Air Occupant Density Lighting Load
Air Rate Exhaust Rate
Space Type Rate [cfm/ft2] [ppl/ft2] Air Class Space Type Air Rate Rate [cfm/ft2] [ppl/ft2] Air Class Space Type Air Class Space Type Factor [W/ft2] /
[cfm/person] [cfm/ft2]
L/s (ppl /M2) [cfm/person] L/s L/s (ppl /M2) (W/M2)
L/s

Daycare (through age 4) 10 / 5 0.18 / 0.9 40 / 4 2 Auditorium Seating Area 5 / 2.5 0.06 / 0.3 6.7 / 0.7 1 Arenas 0.50 1 Classroom/Lecture/Training 1.24 / 13.4

Daycare Sickroom 10 / 5 0.18 / 0.9 40 / 4 3 Places of Religious Worship 5 / 2.5 0.06 / 0.3 8.4 / 0.9 1 Art Classrooms 0.70 2 Conference/Meeting/Multipurpose 1.23 / 13.3

Classrooms (ages 5-8) 10 / 5 0.12 / 0.6 40 / 4 1 Courtrooms 5 / 2.5 0.06 / 0.3 14.3 / 1.5 1 Auto Repair Rooms 1.50 2 Corridor/Transition 0.66 / 7.2

Classrooms (ages 9 plus) 10 / 5 0.12 / 0.6 28.6 / 2.9 1 Legislative Chambers 5 / 2.5 0.06 / 0.3 20 / 2 1 Barber Shops 0.50 2 Dining Area - Bar/Lounge/Leisure 1.31 / 14.2
Public Assembly
Spaces
Lecture Classroom 7.5 / 3.8 0.06 / 0.3 15.4 / 1.6 1 Libraries 5 / 2.5 0.12 / 0.9 100 / 10 1 Beauty and Nail Salons 0.60 2 Dining Area - For Family Dining 0.89 / 9.6

Lecture Hall (fixed seats) 7.5 / 3.8 0.06 / 0.3 6.7 / 0.7 1 Lobbies 5 / 2.5 0.06 / 0.3 6.7 / 0.7 1 Cells with Toilet 1.00 2 Dining Area - Other 0.65 / 7

Art Classroom 10 / 5 0.18 / 0.9 50 / 5 2 Museums - Children's 7.5 / 3.8 0.12 / 0.6 25 / 2.5 1 Copy, Printing Rooms 0.50 2 Dormitory - Living Quarters 0.38 / 4.1
Educational
Facilities
Science Laboratories 10 / 5 0.18 / 0.9 40 / 4 2 Museums/Galleries 7.5 / 3.8 0.06 / 0.3 25 / 2.5 1 Darkrooms 1.00 2 Electrical/Mechanical 0.95 / 10.3

University/College Laboratories 10 / 5 0.18 / 0.9 40 / 4 2 Dwelling Unit 5 / 2.5 0.06 / 0.3 - 1 Educational Science Labs 1.00 2 Food Preparation 0.99 / 10.7
Residential
Wood/Metal Shop 10 / 5 0.18 / 0.9 50 / 5 2 Common Corridors 0.06 / 0.3 - 1 Janitor Closets, Trash/Rec. Rms 1.00 3 Hotel - Hotel Guest Rooms 1.11 / 12

Computer Lab 10 / 5 0.12 / 0.6 40 / 4 1 Sales (except as below) 7.5 / 3.8 0.12 / 0.6 66.7 / 6.7 2 Kitchenettes 0.30 2 Laboratory - For Classrooms 1.28 / 13.8

Media Center 10 / 5 0.12 / 0.6 40 / 4 1 Mall Common Areas 7.5 / 3.8 0.06 / 0.3 25 / 2.5 1 Kitchens, Commercial 0.70 2 Lab - For Medical/Industrial 1.81 / 19.5

Music/Theater/Dance 10 / 5 0.06 / 0.3 28.6 / 2.9 1 Barbershop 7.5 / 3.8 0.06 / 0.3 40 / 4 2 Lockers - Athletic, Ind., & Health 0.50 2 Library - Reading Area 0.93 / 10.1

Multiuse Assembly 7.5 / 3.8 0.06 / 0.3 10 / 1 1 Retail Beauty and Nail Salon 20 / 10 0.12 / 0.6 40 / 4 2 Shower Rooms - Cont. Exhaust 20 CFM/Unit 2 Library - Stacks 1.71 / 18.5

Restaurant Dining Rooms 7.5 / 3.8 0.18 / 0.9 14.3 / 1.5 2 Pet Shops (animal areas) 7.5 / 3.8 0.18 / 0.9 100 / 10 2 Shower Rooms - Inter. Exhaust 50 CFM/Unit 2 Lobby - For Elevator 0.64 / 6.9

Food and Cafeteria/Fast-Food Dining 7.5 / 3.8 0.18 / 0.9 10 / 1 2 Supermarket 7.5 / 3.8 0.06 / 0.3 125 / 12.5 1 Locker Rooms - All Other 0.25 2 Lobby - Other 0.9 / 9.7
Beverage
Services Bars, Cocktail Lounges 7.5 / 3.8 0.18 / 0.9 10 / 1 2 Coin-Operated Laundries 7.5 / 3.8 0.12 / 0.6 50 / 5 2 Paint Spray Booths - 4 Locker Room 0.75 / 8.1

Kitchen (cooking) 7.5 / 3.8 0.12 / 0.6 50 / 5 2 Gym, Sports Arena (play area) 20 / 10 0.18 / 0.9 142.9 / 14.3 2 Parking Garages 0.75 2 Lounge/Recreation 0.73 / 7.9

Break Rooms 5 / 2.5 0.06 / 0.3 40 / 4 1 Spectator Areas 7.5 / 3.8 0.06 / 0.3 6.7 / 0.7 1 Pet Shops (Animal Areas) 0.90 2 Office - Enclosed 1.11 / 12

Coffee Stations 5 / 2.5 0.06 / 0.3 50 / 5 1 Swimming (pool & deck) - 0.48 / 2.4 - 2 Refrigerating Machinery Rooms - 3 Office - Open Plan 0.98 / 10.6

General Conference/Meeting 5 / 2.5 0.06 / 0.3 20 / 2 1 Disco/Dance Floors 20 / 10 0.06 / 0.3 10 / 1 2 Res. Kitchens - Cont. Exhaust 50 CFM/Unit 2 Parking Garage - Garage Area 0.19 / 2.1
Sports and
Corridors -/ 0.06 / 0.3 - 1 Health Club - Aerobics Room 20 / 10 0.06 / 0.3 - 2 Res. Kitchens - Inter. Exhaust 100 CFM/Unit 2 Restrooms 0.98 / 10.6
Entertainment
Storage Rooms (Liquids or Gels) 5 / 2.5 0.12 / 0.6 500 / 50 2 Health Club - Weight Rooms 20 / 10 0.06 / 0.3 100 / 10 2 Soiled Laundry Storage Rooms 1.00 3 Sales Area 1.68 / 18.1

Bedroom/Living Room 5 / 2.5 0.06 / 0.3 100 / 10 1 Gambling Casinos 7.5 / 3.8 0.18 / 0.9 8.4 / 0.9 1 Storage Rooms, Chemical 1.50 4 Stairway 0.69 / 7.5

Barracks Sleeping Areas 5 / 2.5 0.06 / 0.3 50 / 5 1 Game Arcades 7.5 / 3.8 0.18 / 0.9 50 / 5 1 Toilets - Private - Cont. Exhaust 25 CFM/Unit 2 Storage 0.63 / 6.8

Hotels, Motels, Laundry Rooms - Central 5 / 2.5 0.12 / 0.6 100 / 10 2 Stages, Studios 10 / 5 0.06 / 0.3 14.3 / 1.5 1 Toilets - Private - Inter. Exhaust 50 CFM/Unit 2 Workshop 1.59 / 17.2
Resorts,
Dormitories Laundry Rooms - In Dwelling Units 5 / 2.5 0.12 / 0.6 100 / 10 1 Toilets - Public - Normal 50 CFM/Unit 2

Lobbies/Prefunction 7.5 / 3.8 0.06 / 0.3 33.4 / 3.4 1 Note: Table reduced to most common space types. See ASHRAE for full table. Toilets - Public - Heavy Use 70 CFM/Unit 2
Note: Table reduced to most common space
types. See ASHRAE for full table
Multipurpose Assembly 5 / 2.5 0.06 / 0.3 8.4 / 0.9 1 Woodwork Shop/Classroom 0.50 2

Breakrooms 5 / 2.5 0.12 / 0.6 20 / 2 1

Main Entry Lobbies 5 / 2.5 0.06 / 0.3 100 / 10 1 ASHRAE PEOPLE LOADS ASHRAE EQUIPMENT LOADS
Storage Rooms (Dry Materials) 5 / 2.5 0.06 / 0.3 500 / 50 1 Total Heat [Btu/h]
Sensible Heat Latent Heat Load Factor
Office Buildings Space/Activity Type Type of Use Description
[Btu/h] [Btu/h] [W/ft2] / (W/M2)
Office Space 5 / 2.5 0.06 / 0.3 200 / 20 1 Adult Male

Reception Areas 5 / 2.5 0.06 / 0.3 33.4 / 3.4 1 Seated at Theater - Matinee 390 225 105 100% Laptop - Light 167 ft /workstation, all laptop use, 1 printer per 10, speakers, misc.
2
0.25 / 2.7

Telephone/Data Entry 5 / 2.5 0.06 / 0.3 16.7 / 1.7 1 Seated at Theater - Night 390 245 105 100% Laptop - Medium 125 ft2/workstation, all laptop use, 1 printer per 10, speakers, misc. 0.33 / 3.6

Bank Vaults/Safe Deposit 5 / 2.5 0.06 / 0.3 200 / 20 2 Seated, Very Light Work 450 245 155 50% Laptop - Light 167 ft2/workstation, 50% laptop use/50% desktop, 1 printer per 10, speakers, misc. 0.4 / 4.4

Banks or Bank Lobbies 7.5 / 3.8 0.06 / 0.3 66.7 / 6.7 1 Moderately Active Office Work 475 250 200 50% Laptop - Medium 125 ft2/workstation, 50% laptop use/50% desktop, 1 printer per 10, speakers, misc. 0.5 / 5.4

Computer (not printing) 5 / 2.5 0.06 / 0.3 250 / 25 1 Standing, Light Work; Walking 550 250 200 100% Desktop - Light 167 ft2/workstation, all desktop use, 1 printer per 10, speakers, misc. 0.6 / 6.5

Freezer / Refr. Spaces (<50°F) 10 / 5 0/ - 2 Walking, Standing - Drug Store, Bank 550 250 250 100% Desktop - Medium 125 ft2/workstation, all desktop use, 1 printer per 10, speakers, misc. 0.8 / 8.7

General Manufacturing 10 / 5 0.18 / 0.9 142.9 / 14.3 3 Sedentary Work - Restraurant 490 275 275 100% Desktop - Two Monitors 125 ft2/workstation, all desktop use, 2 monitors, 1 printer per 10, speakers, misc. 1 / 10.8

Pharmacy (prep. area) 5 / 2.5 0.18 / 0.9 100 / 10 2 Light Bench Work - Factory 800 275 475 100% Desktop - Heavy 85 ft2/workstation, all desktop use, 2 monitors, 1 printer per 8, speakers, misc. 1.5 / 16.2
Miscellaneous
Spaces
Photo Studios 5 / 2.5 0.12 / 0.6 100 / 10 1 Moderate Dancing - Dance Hall 900 305 545 100% Desktop - Full On 85 ft2/workstation, all desktop use, 2 monitors, 1 printer per 8, speakers, misc., no diversity. 2 / 21.6

Shipping/Receiving 10 / 5 0.12 / 0.6 500 / 50 2 Walking 3 mph; Light Mach. Work 1000 375 625

Sorting, Packing, Light Assembly 7.5 / 3.8 0.12 / 0.6 142.9 / 14.3 2 Bowling - Bowling Alley 1500 580 870 Building Cooling Loads Fire Spinkler Pipe Sizes
Telephone Closets -/ 0/ - 1 Heavy Work - Factory 1500 580 870 General Buildings 90 W/M2 250-350 Ft2 / TR Dia MM Dia Inch No. of Spinklers

Transporation Waiting 7.5 / 3.8 0.06 / 0.3 10 / 1 1 Heavy Mach. Work; Lifting - Factory 1600 635 965 Educational buildings 100 W/M2 150-300 Ft2 / TR 25 1 2

Warehouses 10 / 5 0.06 / 0.3 - 2 Athletics - Gymnasium 2000 710 1090 Industrial buildings 80 W/M2 150-300 Ft2 / TR 32 1 1/4 3

Offices 70 W/M2 250-350 Ft2 / TR 38 1 1/2 5

Residential buildings 60 W/M2 350-400 Ft2 / TR 50 2 10

Retail buildings 110 W/M2 150-300 Ft2 / TR 65 2 1/2 20

80 3 40

100 4 100
General Buildings 90 W/m2
Educational buildings 100 W/m2
Industrial buildings 80 W/m2
Offices 70 W/m2
Residential buildings 60 W/m2
Retail buildings 110 W/m2
250-350 Ft2 / TR
150-300 Ft2 / TR
150-300 Ft2 / TR
250-350 Ft2 / TR
350-400 Ft2 / TR
150-300 Ft2 / TR