Ventilation Systems

Table of Contents

Ceiling Fans

Size of ceiling fan

Size of a ceiling fan should be chosen based on the actual working area and not on the basis of total room area so that unnecessary energy is not wasted. The design criterion based on number of air changes results in excess requirement. For a working zone with longer dimension as D meters, ceiling fan should be of capacity 55 D m³/min. The capacities of different fan sizes, respective diameter of the ventilation zone and power consumption in W/m² is:

Ceiling Fan
Fan Size (mm)900 mm1200 mm1400 mm1500 mm
Capacity (m³/min)170230290320
Diameter of ventilated zone (m)3.04.25.25.6
Power consumption (W/m²)7.84.63.33.0

Fans should be uniformely distributed over the entire working area and their optimal number and size should be worked out based on the above table.

Minimum clearance of fan blades with ceiling should be maintained as 0.3 m. Height of fan blade above the floor should be (3 H + W) / 4, where H is the height of the room and W is the height of the working plane.

Exhaust Fans

Typical Performance Characteristics of Industrial Fans (Exhaust Fans)
S.No.Impeller dia. (mm)Speed (rpm)Input (W)PhaseCurrent (A)Free air flow (m³/h)Free air flow (cfm)
1305140082Single0.3719001120
238090085Single0.3924601450
33801400160Single0.7040002350
438090085Three0.2024601450
53801400160Three0.4040002350
6457900132Single0.6043402550
74571400370Single1.7068004000
8457900132Three0.3043402550
94571400370Three0.7068004000
10610700240Single1.1079004650
11610900500Single2.30104506150
12610700240Three0.5079004650
13610900500Three0.90104506150
14915550700Three1.502210013000
159157001200Three2.402800016460

Note

Single / three phase fans are rated for 230 V / 415 V, 50 Hz respectively.

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