The rates of outdoor make up air in the table below can be used as a guideline in design of ventilation systems.

Type of Building and Room

Air Shiftsper hour

(1/h)

Airflow(l/s per m2

floor area)

OutdoorAirflow

(l/s)

Animals

Sheep 3 per animal

Horses 40 per animal

Hens 3 per animal

Cows100 per animal

Chickens 2 per animal

Pigs, sow 60 per animal

Piglet 15 per animal

Apartments15 - 20 per

person

Assembly halls 5 - 10 14 per person

Auditoriums10 - 15 per

person

BakeriesProduction 8

Pastry room 6

BanksService 2 - 3Archive 1

Staff 2 - 3Baths 5 - 8 15

Barber Shops15 - 25 per

person

Bars15 - 25 per

person

Beauty Shops15 - 25 per

person

Bowling Alleys15 - 20 per

person

Cafeterias 410 - 15 per

person

Cinemas/Theatres

5 - 107 - 15 per

person

Chemist's shops

Sterile room 15Laboratory 15

Packing room 4Store 1

Churches 210 - 15 per

person

Clubhouses15 - 25 per

person

Cocktail Lounges15 - 25 per

person

Computer Rooms15 - 20 per

person

Court Houses10 - 15 per

person

Dance halls15 - 30 per

personDental Clinics,

Offices15 - 20 per

personDepartment

Stores (cfm/Sq.Ft)0.3

Dining Halls10 - 15 per

person

Drug Shop10 - 15 per

personEngine rooms 4Exhibition halls 10 - 20

Fire Stations15 - 20 per

personGarages 5 - 6 > 1

Hospitals

General 25 per personTherapy 9

Operating theatre

14

Autopsy 9

HotelsReception

15 - 20 per person

Room 3Industries

Factory20 - 30 per

personCarpenter work shop

2 - 5

Car repair shop

4

Car repair shop, exhaust

60 - 80 per car

outletMechanical work shop

3 - 4

Welding 12 - 15Assembly 4 - 5

Jails10 - 15 per

person

Jewelry Shop10 - 15 per

person

Libraries10 - 15 per

personLunch Rooms, Luncheonettes

10 - 15 per person

Municipal Buildings

10 - 15 per person

Museums10 - 15 per

personSmithies 6 - 7

Kitchens

Small 20 - 40Large 10 - 20< 7 m2 15> 7 m2 20

Industrial in general

25 - 30

Gas ovens550/m2

outside wall

Electric ovens300/m2

outside wall

Grill table400/m2

outside wallFrying pan 300Boiling pan

100 l100

Boiling pan 200 l

200

Coffee machine

60

Refrigerated cabinet

7 - 10

Cooling and freezer room

0.3 - 0.5

Store 2 - 4Laundries 10 - 15Lavatories 5 - 10 10

Night Clubs15 - 25 per

personMalls 10 - 15 per

person

Motels15 - 20 per

person

Offices

Module 3 - 815 - 20 per

personLandscape 20 per personConference

room15 - 30 per

person

Lecture room10 - 15 per

person

Dining hall15 - 20 per

personStaff,

changing clothes

8 - 12

Dining room 8 - 10Resting room 15 per person

Police Stations15 - 20 per

person

Post Offices15 - 20 per

personPrecision

Manufacturing15 - 20 per

person

Restaurants 5 - 10 1015 - 20 per

personRetail Stores (cfm/Sq.Ft)

0.3

Schools Classroom 4 - 510 - 15 per

personShops 20 per person

Shopping Centers10 - 15 per

personSports halls 3 - 4

Supermarkets10 - 15 per

personSwimming pools 5 - 10

Taverns15 - 25 per

person

Town Halls15 - 20 per

person

1 dm3(litre)/s = 10-3 m3/s = 3.6 m3/h = 0.03532 ft3/s = 2.1189 ft3/min (cfm) = 13.200 Imp.gal (UK)/min = 15.852 gal (US)/min

Dust Concentration

Common dust concentrations exposed to filters in ventilation and air-condition systems

Rural and suburban districts - 0.45 to 1.0 mg/m3 air Metropolitan districts - 1.0 to 1.8 mg/m3 air Industrial districts - 1.8 to 3.5 mg/m3 air

Types of Filters

Washers

Large Air velocity through washer 2.5 m/s Water pressure required for spray nozzles 140 - 170 kN/m2

Water pressure required for flooding nozzles 30 - 70 kN/m2

Dry Filters

Felt, cloth, cellulose, glass, silk etc. without adhesive liquid

Flat Panel type - disposable Filters

Air velocity 0.1 - 1.0 m/s Resistance 25 - 250 N/m2

Efficiency 20-35%

Continuous roll - self cleaning Filters

Air velocity 2.5 m/s Resistance 30 - 175 N/m2

Efficiency 25%

Bag Filters

Efficiency 40-90%

HEPA (High Efficiency Particulate Air) Filters

Efficiency 99.97% for 0.3 micron particles and larger

ULPA (Ultra Low Penetrating Air) Filters

Efficiency 99.9997 for 0.12 micron particles or larger

Viscous Filters

Panel type - cloth with viscous fluid coating - washable or disposable

Plates about 500 mm x 500 mm Air velocity 1.5 - 2.5 m/s Resistance 20 - 150 N/m2

Continuous roll - continuously moving, self cleaning

Air velocity 2.5 m/s Resistance 30 - 175 N/m2

Electrostatic Precipitators

Cleaned automatically Air velocity 1.5 - 2.5 m/s Resistance negligible Efficiency 30-40%

Absolute

Dry panel with special coating - disposable or self cleaning Air velocity 2.5 m/s Resistance 250 - 625 N/m2

Standard European Filter Classification

Filter General propertiesClas

sEffect Applications

Basis filters

In general:- produced in synthetic

fibers- efficient for particles

> 4-5 mm- air speed < 2.5 m/s- start pressure drop approximately 50 Pa- final pressure drop

approximately 150 Pa

EU1

Protects against insects and fibers.

Limited effect against larger pollen (<70%)

Ineffective against smoke and blacking

particles

Window unitsHeat exchangers

Air heatersFiber filters in textile industry

EU2

Effective against larger pollen

(>85%) and larger atmospheric dust.

Limited effect against dust and blacking particles

Heating and cooling units in

electrical transformers

garagesindustrial halls

offices in industry

EU3

Effective against larger pollen

(>85%) and larger atmospheric dust.

Limited effect against dust and blacking particles

Heating and cooling units in

electrical transformers

garagesindustrial halls

offices in industry

EU4Limited effect

against dust and blacking particles

In addition to EU3 kitchens and spray paint work shops

Fine filters

In general:- produced in glass

fibers- efficient for particles

> 0.1 mm- air speed < 2- 3 m/s

EU5 Effective against pollen and finer

atmospheric dustConsiderable effect

against smoke.No effect against

Churches, sport halls, department stores, schools,

hotelsFood stores

- start pressure drop approximately 50-100

Pa- final pressure drop approximately 200 -

250 Pa

tobacco smoke

EU6 As EU5 As EU5

EU7Effective against

pollen and blacking dust

As EU6and food industry,

laboratories, theatres, hospital

rooms, data rooms

EU8

Very effective against particles

and blacking.Very effective

against microbes.Effective against tobacco smoke.

Operating theatres, production rooms for fine optics and

electronics.Hospital

examination rooms.

EU9 As EU8 As EU8

Micro filters

In general:- produced in glass

fibers in combination with separators of paper, plastic or

aluminum- efficient for particles

> 0.01 mm- air speed < 0.5 - 1.0

m/s- start pressure drop

approximately 250 Pa- final pressure drop according life span

and economy

EU10

EU11

EU12

EU13

EU14

Air flow, air velocity and required air-duct area is indicated below:

 

1 ft/min = 5.08x10-3 m/s 1 ft3/min = 1.7 m3/h = 0.47 l/s 1 ft2 = 0.0929 m2 = 144 in2

The diagram below indicates velocity and dynamic pressure in air ducts.

Pressure loss and air flow velocity for some common duct sizes and air flow volumes can be taken from the table below:

Pressure Loss (inches water gauge per 100 feet duct)

Air velocity (ft/min)

Air Volume (cfm)Duct Size (inches)

4 5 6 8 10 12 16

1000.65 0.21 0.09 0.02 0.01

1146 733 509 286 183

2000.8 0.32 0.08 0.02 0.01

1467 1019 573 367 255

4001.19 0.28 0.09 0.04 0.01

2037 1146 733 509 286

8000.34 0.14 0.03

1467 1019 573

16000.12

1146

The air velocity should not exceed certain limits to avoid unacceptable noise generation

Friction loss in standard air ducts are indicated in the diagram below.

1 m/s = 196.85 ft/min 1 m3/s = 3600 m3/h = 1000 dm3(liter)/s = 35.32 ft3/s = 2118.9 ft3/min =

13200 Imp.gal (UK)/min = 15852 gal (US)/min 1 mm H2O = 9.81 Pa = 9.807x10-6 N/mm2 = 0.0987 10-3 bar = 1 kp/m2 =

0.09678 10-3 atm = 1.422 10-3 psi (lbf/in2)

Example - Air Duct and Friction Loss

The friction loss in a 500 mm main duct in comfort system with air flow 1 m3/s can be estimated as indicated below to 0.05 mm H2O/m (~ 0.5 Pa/m).

The air velocity in the duct is 5 m/s.