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CALCULATION – SELECTION PROCEDURE

Determine Volume of space to be ventilated
Volume (ft3)+ L x W x H, Where L+ Length, W= width, H=Ht. of building
Select air changes per hour inside working area from table A
Calculate required ventilation rate Q (cfm)
Q(cfm)= Volume (ft3) x Air change Rate 60

Determine number of ventilators = Ventilation Rate Q
Exhaust Capacity

Example:

Building dimensions with L=100ft,W=60ft,H=20ft.
Volume (ft3)=120000 ft3.
Air change rate selected =12 times per hour.(from Table-A)
Calculations required ventilation rate Q(cfm)
Q(cmf)= volume (ft3) x air change rate

Ventilation rate Q(cfm) = 120000x12 = 24000 cfm 60

Refer table B,select suitable table model from table is wind-e 22’’
Exhaust capacity = 1084, 1 ventilator per hour.
Under wind velocity of 5mph,temp. diff. of 5 degrees, stack height =20 ft.
Air turbine ventilators required quantity = 24000 cfm =22 Nos.
1084
Selection is 22 Nos. of wind-e 22”

Table-A Recommended Air changes rates

Typing of building Air change per hour Typing of Building Air change per hour
Assly Hall 6-12 Factories(Heavy) 10-30
Auditorium 4-12 Laundry 12-30
Bakeries 12-20 Paper Mill 8-30
Boiler Room 15-60 Textile Mills 4-12
Brewery 8-30 Packing Room 8-30
Class Room 10-15 Transformer Room 12-30
Engine Room 12-30 Paint Shops 10-30
Factories(Light) 6-12 Warehouse 4-6

Table - B : Performance Data

Wind Velocity(Mph) 5 8 10
Temp. Diff. °C 3 5 10 3 5 10 3 5 10
Model No. Throat size (inc) Stack height Exhaust Capacity in cfm
Wind-e 22 10 939 1000 1102 1436 1498 1600 1792 1854 1958
    20 1005 1084 1216 1503 1582 1714 1859 1938 2070
    30 1058 1154 1314 1556 1652 1812 1915 2010 2168
    40 1107 1216 1398 1605 1714 1896 1961 2070 2252