VENTILATION SYSTEMS

Axial Fans

  • Heavy duty (Working 24h/day)
  • Two bearing housing
  • V-belt drive or in line drive by using coupling
  • Capacities 10,000 m3/h up to 250,000 m3/h
  • Statically and dynamically balanced.

 

 

 

 

 

 

 
Units are supplied complete with comprehensive instructions, which give full details on installation methods for each different unit. Should problems arise in the field, please do not hesitate to call our Technical department for further advice.

 

 

 

 

 

 

 

 

 

 

 

SITING

          When deciding where to place equipment, keep in mind what the best airflow will be to achieve the maximum results.

Air is liquid in a gaseous state. It will flow just like liquid.

Make note of existing air patterns in the room. The air pattern you design for the air

cleaning system must not conflict with the one that is created by existing heating or air conditioning outlets. Remember the best

effect will be achieved by blowing clean air into the dirty area.

 

 

The secret of avoiding “dead” areas is to try and maintain a circulating air pattern around the room with all air movers helping each other and not fighting against each other, This becomes particularly important when more than one unit is in use.

 

 

If you blow straight into the L of L shape rooms you will set up local air flows. Such out of the L when you only have one unit.

In all applications it is essential to avoid draughts. This can be done by keeping the main airflow above head height-smoke rises anyway.

Beware of ceiling beams or other obstructions. With a range of both wall and ceiling units it is usually possible to apply the right equipment

 to achieve the best results.

 

VENTILATION GUIDELINES

Airflow rate

This is the air volume required to extract or supply air into a room during a given time.

Several methods can be used to calculate the airflow:

1.   After calculating the volume of the room, multiply volume by the number of air changes per hour (ACH):

This calculates the air flow required in meters cubed/hr (m3/h)

INDUSTRIAL PREMISES
ACH

Boiler rooms

20  - 30

Dye works

10  - 15

Electroplating shops

10  - 15

Engine rooms

20  - 30

Factories and workshops

3  - 6

Foundries

30  - 60

Laundries

30  - 60

Paint shops

30  - 60

Stores and warehouses

3  - 6

Welding shops

15  - 30
 
COMMERCIAL PREMISES
ACH

Assembly rooms

4  - 8

Bakeries

20  - 30

Banks

3  - 4

Café and coffee bars

10  - 12

Canteens

5  - 10

Cinemas and theatres

5  - 8

Conference rooms

8  - 12

Dance halls

6  - 8

Entrance halls

3  - 5

Garages

6  - 8

Gymnasium

6  - 12

Hair dressing salons

10  - 15

Hospital sterilizing wards

4  - 6

Commercial kitchens

15  - 30

Laboratories

8  - 12

Launderettes

15  - 30

Lavatories

8  - 15

Libraries

3  - 5

Offices

4  - 8

Photo and X-ray darkrooms

10  - 15

Recording studios

10  - 12

Restaurants

6  - 10

Schoolrooms

2  - 4
 

These values must not take the place of any regulation requirements and can be modified for particular applications.

 

2.   Depending on the ventilation rates per person:

 

§  20  - 25 m3/h per person for normal activity.

§  30  - 35 m3/h per person if smoking is allowed.

§  45 m3/h per person in case of light physical work.

§  60 m3/h per person in case of greater physical activity.

 

These values are minimum air flows.

 

3.   Air velocity required for capturing or transporting particular matter.

CAPTURE VELOCITY

Cooker hoods

 
  • Domestic kitchen

from 0.15 to 0.20m/s
  • Commercial kitchen

from 0.20 to 0.25m/s

Evaporating tanks

from 0.25 to 0.50m/s

Degreasing

from 0.25 to 0.50m/s

Welding, dipping

from 0.50 to 1.00m/s

Galvanizing

from 0.50 to 1.00m/s

Spray booths

from 0.70 to 1.00m/s

Grinding down rectification

from 2.50 to 10.00m/s

 

TRANSPORT VELOCITY

Dust

9 m/s

Flour

13 m/s

Saw dust

15 m/s

Metallic dust

15 m/s

Wood chips

18 m/s

Lead dust

20  - 25 m/s

To calculate air volume (m3/s) it is necessary to multiply the air velocity by the duct cross sectional area.

CHOICE OF FAN

  The fan selection must take into account some parameters such as:

 1.      Type of premise:

  • Industrial
  • Commercial
  • Domestic...

 2.      Nature of the air and its characteristics:

  • Clean air
  • Air + dust or grease
  • Special fluid (gases)

 3.      Nature of the installation:

  • Supply and extract
  • Wall fan, roof fan, ducted systems..
  • Position of the air entries
  • Particular conditions....

 4.      Requirements of air flow and pressure drop

 5.      Acceptable sound level:

  • In the room
  • Externally

 6.      Type of mains supply:

  • Single phase, three phase
  • Voltage
  • Frequency...

 7.      Other parameters may be considered for the selection such as:

  • Dimensions
  • Speed controllable motors
  • Mounting accessories...
 

The fan laws

 

These laws enable you to change the aerodynamic parameters:

§  Airflow (Q)

§  Pressure drop (Dp)

§  Power absorbed by the impeller (P)

§  Sound level (Lp)

As function of:

§  The speed (RPM) (N)

§  The impeller diameter (D)

and that, for fans geometrically similar.

 

                     1.        For a given impeller diameter, changing the speed from N1 to N2

Conversion Tables

Volume flow:

1 CFM             = 1,699m3/h

                        = 0,472 l/s

1 m3/h              = 0,589 CFM

                        = 0,278 l/s

1 l/s                  = 2,119 CFM

                        = 3,6

Velocity:

1 ft/min           = 0,0051 m/s

1 ms                 = 196 ft/min

Volume:

ft3                    = 0,00283 m3

m3                    = 35,31 ft3

Pressure:

1 inWG           = 249 Pa

                        = 25,4 mmWG

1 Pa                 = 0,004 inWG

1 mmWG        = 0,0393 inWG