Calculation of ventilation in short

By

Dr.Syed Irfan Hussain

Calculation of ventilation for Poultry Broiler Breeders Farm colored atlas

Note this page can also be translated to Arabic , urdu etc                                                                

Air exchange area and calculation of fans in a poultry house

Air exchange area  m³/minute = Length width height

For example

Air exchange area m³/minute =  120m×12m×03m =4320m³

Air exchange area m³/minute =  4320 m³

No. of fan needed for air exchange  =

 Air volume m³/minute   Air exchange capacity of Fan

Standards  

                    1. Fan with a diameter of 1.2m      = 566 m³/minute  

                    2. Fan with a diameter of 1.0m      = 283 m³/minute  

                    3. Fan with a diameter of 91cm     = 255 m³/minute  

For example

No. of fan needed for air exchange = Air volume m³/minute ÷ Air exchange capacity of Fan

No. of fan needed for air exchange =  4320 ÷ 566 =7.6 or 8 Fans

No. of fan needed for air exchange = 08 fans

                                                                                                                                                               

                                                                                                                                                               

Calculation of space for Cooling Pad in poultry house(m²) =

(Fan air exchange Capacity m³/minute × Number of fans)÷ AirSpeed through cooling pad m³/minute

Standards

    3. For 100mm (10cm or 4-in) thick Pad,
                                                                use     ( 1.27m/s  or 76m/minute )(250fpm)

    4. For 150mm (15cm or 6-in) thick Pad, 
                                                                use   ( 1.91m/s or  114/minute ) (375fpm)

For example

Cooling  Pad area m²
= (Fan air exchange Capacity m³/minute × No. of fans)÷ (Air Speed through cooling pad m³/minute)

Cooling  Pad area = (566  × 8 )÷114 = 39.7m²  Or  40m²

*It means  20m² (2m in width and 10 m in length) on each side of the house

Cooling  Pad area in m² = 40m²

The number of fans Needed to exchange required air velocity

=(Required Air velocity m/s  ) ÷{  Fan capacity ÷ (width × Height ×60) }

Standard  Air velocity

Rearing      ˃ 2.03 meters per second (m/s) OR 400 Feet per minute (fpm)

Production ˃ 2.54 meters per second (m/s) OR 500 Feet per minute (fpm)

For example

The number of fans Needed to exchange required air velocity = 

(Required Air velocity m/s  ) ÷{  Fan capacity ÷ (width × Height ×60) }

No. of fans Needed to exchange required air velocity  =(2.03) ÷ { 566 ÷(12×03×60} =7.8 fans

No. of fans Needed to exchange required air velocity  = Fans 8

Minimum Ventilation Calculation For Fan Timer Setting

Standards

Minimum ventilation per bird

Age	Cubic meter per hour (CMH/Bird)	Cubic feet per minute (CFM/Bird)
01-08 weeks	0.16	0.10
09-15 weeks	0.42	0.25
16-35 weeks	0.59	0.35
35- depletion	0.76	0.45

For example

Bird Age = 20 weeks

Number of Birds = 10,000

Minimum ventilation fan = 1 × 91 cm =255 m³/minute × 60 =( 15300m³/hr )

Using a 5 minutes cycle timer

Calculate the minimum Ventilation?

Step:1

 Ventilation rate = (Minimum ventilation per bird) ×( Number of Birds)

             Ventilation rate= (0.59 cmh) ×(10,000) = 5,900 cmh (cubic meter per hours)

Percentage time the fans needed to be run for

Step:2 

Percentage time = (Total ventilation needed) ÷ (Total capacity of fans used)

Percentage time =(5,900cmh) ÷ (15,300) =0.39 or 39%

Percentage time =39%

*It means if a 5-minute timer is used, the run timer required would be then 39% of  5 minutes or 117 seconds

( or the fan should be 24 sec on and 36 sec off for each minute)

                                                                                                                                                               

For example

Bird Age = 01 weeks

Number of Birds = 10,000

Minimum ventilation fan = 1 × 91 cm =255 m³/minute × 60 =( 15300m³/hr )

Using a 5 minutes cycle timer

Calculate the minimum Ventilation?

Step:1

 Ventilation rate = (Minimum ventilation per bird) ×( Number of Birds)

             Ventilation rate= (0.16 cmh) ×(10,000) = 1600 cmh (cubic meter per houre)

Percentage time the fans needed to be run for

Step:2 

Percentage time = (Total ventilation needed) ÷ (Total capacity of fans used)

Percentage time =(1600cmh) ÷ (15,300) =0.10 or 10%

Percentage time =10%

*Assuming a 05-minute cycle timer, the run Timer required would then be 10 % of 05 minutes or 30 seconds 

                                                                                                                                                               

Ventilation standers for Layers