OMAFRA Work Sheets – Ventilation, Heating, and Cooling

 

The worksheets in this document are from OMAFRA’s Publication 833 Ventilation For livestock and Poultry Facilities. This resource is an excellent resource for troubleshooting existing or designing new ventilation. Most people don’t know that the publication exists because it is only offered in print and must be found in the bowels of the Publications Ontario Website. We would highly recommend you order a copy of the guide for yourself.

T-Table Approximate Heater Sizing Calculations Chart
1 Outside design temperatures

Can be found in the Ontario Building Code SB-1 Climate Information

Degrees Celsius
2 Number of animals housed and BTU/h per animal at minimum weight (appendix D) Animals BTU/h – animal
3 Number of animals housed and BTU/h per animal at maximum weight (appendix D) Animals BTU/h- animal
4 Maximum BTU/h for minimum weight animals at design temperature ____# animals x ____ BTU/h – animal BTU/h
5 Maximum BTU/h for maximum weight animals at design temperature ____# animals x ____ BTU/h – animal BTU/h
6 Recommended heater output size BTU/h

 

Inlet Size Work Sheet

1 Number of _________ animals housed (type) #
Number of animals: 15 calves from birth to 10 weeks of age.
2 Warm weather ventilation rate from Appendix B CFM
From Appendix B: Warm weather air flow rate for calves = 120CFM
3a Maximum air flow based on animal numbers _____# of animals x ______CFM/animal CFM
Max air flow rate 15 calves x 120cfm = 1800 CFM
3b Maximum air flow based on 1 air change per minute (_____ft room length x ______ft room width x _____ft room height x 60 air change/hour) 60 minutes/hour CFM
Max air flow based on 1 air change/minute; (12ft x 50ft x 8ft x 60 air change /hr)/60 mon/hr = 4,800 CFM this rate is too high for claves which are considered sensitive animals and should never be exposed to drafts
3c Maximum air flow based on other design criteria specified by the designer CFM
In certain cases a designer may specify some other design criterion based on their experience with this type of livestock. For example, the need to achieve 2 air changes per minute in a high density case layer facility to extract the bird heat more quickly and help maintain a more comfortable environment for the birds.
4 Minimum air intake area based on 2ft2 per 1,000 CFM (______cfm/1,000) x 2 ft2 ft2
Min air intake are based on2 ft2 /1,000 CFM of air flow capacity calculates as follows: (1,800/1,000) x 2 = 3.6ft2
5 Minimum length of intake opening into room or attic (from building plans = _________ ft) ft
Assuming the attic is used for the fres air supply, there needs to be at least 3.6ft2 (or preferably more) clear opening into the attic. If there is only soffit available across the end walls of this room (12ft wide), there will be 23 useable feet of soffit length.
6 Minimum air intake opening width required (____ft2/(____ft)) = ____ft x (12in/ft) + (1 in. for screening) in.
Minimum air intake opening = 3.6ft2/(24-1)=0.16ft x (12in/ft + 1 in for screening = 3 inch wide opening along both soffits.
7 Maximum warm weather air inlet velocity = 500-1000ft/min based on width of room and sensitivity of animals housed ft/min
Calves are considered sensitive animals and since the room is relatively narrow, use a summer inlet speed of no more than 500ft/min.
8 Minimum air inlet area into room ____ CFM/____ft/min ft2
The ceiling inlet area is: 1,800 CFM/500ft/min = 3.6ft2 of inlet opening.
9a Length of continuous slot type baffle board plan to install (want inlet to be as continuous as possible along length of room) ft
A continuous baffle board type slot inlet is chosen, it is run the full length of the room, less all space required for the cable actuator and cable tension weight. For this room, 46ft of baffle board could be installed but is not practical given the small quantity of air flow required.
9b Number of modular air inlets required based on capacity of each unit (_____ CFM/ ______ manufacturer’s rating) # inlets
Number of modular air inlets based on capacity of each unit: 1,800 CFM/1,000CFM (rating per unit from manufacturer) = 2 units.
9c Number of modular air inlets required based on inlet/10ft of room length (_____ft room length/10ft) # inlets
Number of modular inlets based on a maximum air inlet spacing of 10ft on centre to ensure full rotary air circulation, the number of air inlets required is 50ft/10ft = 5inlets along the 50 ft room length.
9d Choose between a continuous slot air inlet (9a) or the number of modular air inlets (9b or 9c) to install in room. ft or # inlets
 A good choice for this room is 5 modular ceiling air inlets.
10 Total length of air inlet baffle opening from number of modular inlets or length of continuous slot inlet (____ modular units x ____in)/12in/ft or _____ft or slot ft
Total length of air inlet baffle opening: (5 modular inlets x 27 in./inlet)/12in./ft = 11/3ft.
11 Maximum air inlet opening (______ ft2 inlet area/_____ ft inlet length) = _______ ft x (12 in/ft) in.
The maximum air inlet baffle opening needed: 3.6ft2/11.3ft = 0.32ft or 3.8 in. If six air inlets (rather than the minimum five calculated) were installed, the opening would be even less and the air flow a little more uniform since the inlets are located closer together. The most important thing is never to undersize air inlets and do not locate them too far apart in a row.
12a Minimum cold weather ventilation rate from Appendix B _____CFM/animal x _____number of animals CFM
The minimum cold weather ventilation in this calf room using Appendix B is 12CFM x 15 calves = 180CFM.
12b Minimum cold weather air weather air flow based on 4 air changes /hour room volume = (_____ ft room length x ____ ft room width x _____ ft room height)  (60min/hr) x (4 air change/hr) CFM
However, due to a manure pack in the stalls, 4 air changes per hour is required = (12ft x 50ft x 8ft ceiling)/(60 minutes.hr) = 80x(4 air changed/hr) = 320 CFM.
12c Minimum cold weather air flow based on other criteria specified by designer. CFM
In certain cases, a designer may specify some other design criterion based on their experience with this type of livestock. For example, reducing the minimum air exchange rate to 3 air changes per hour based on more frequent bedding cleanout or specifying a minimum ventilation rate based on an existing stage 1 exhaust fan which is already installed in the room.
13 Minimum cold weather air inlet velocity = 500-1000ft/min based on width of room and sensitivity of animals housed ft/min
Based on this narrow room width, a winter inlet velocity of approximately 800ft/min is appropriate.
14 Minimum air inlet area ______ CFM/ ______ft/min Ft2
The minimum ventilation rate requires an air inlet opening are of 320 CFM/800ft/min = 0.4ft2 of inlet opening.
15 Minimum air inlet opening (_____ ft2 inlet area _____ ft inlet length) = _____ ft x (12in /ft) in.
The minimum air inlet opening width assuming 11.3 ft of inlet baffle length is: 0.4ft2/11.3ft = 0.035ft x 12 in./ft = 0.4in

 

Recirculation Duct Work Sheet

1a Minimum cold weather ventilation rate from Appendix B _____ CFM/animal x ______# of animals CFM
  Minimum cold weather ventilation rate: 12CFM x 15 calves = 180 CFM.  
1b Minimum cold weaher air flow based on 4 air changes/hour (____ft room length x ____ft room width x ____ ft room height)  (60 min/hr) = _____ x (4ac/hr) CFM
  Minimum cold weather air flow based on 4 air changes/hour is: (50 ft length x 12 ft width x 8 ft height x 4 air changes/hour) / 60 min/ hr = 320 CFM

This quantity of minimum ventilation is often selected when there is a manure pack in the pens to contribute extra moisture and odours, or with liquid manure and a high nutrient feed that can generate significant odours.

 
1c Minimum cold weather air flow based on other criteria specified by designer CFM
  In certain cases, a designer may specify some other design criterion based on their experience with this type of livestock. For example, the need to reduce the minimum ventilation rate based on an existing Stage 1 exhaust fan which is already installed in the room.  
2a Air flow capacity for recirculation duct based on 3 x selected winter rate: (______CFM x 3) CFM
  Air flow capacity for recirculation duct using 3 x winter rate: 3 x 320 CFM = 960 CFM.  
2b Air flow capacity for recirculation duct based on 0.5-1.5 CFM/ft2 of floor area:

(____ft width x ____ft length) x 0.5

(____ft width x ____ft length) x 1.5

CFM

Range

CFM

  Air flow capacity using 0.5-1.5 CFM/ft2:

0.5 CFM/ft2 x (12ft x 50ft) = 300 CFM

1.5 CFM/ft2 x (12ft x 50ft) = 900 CFM

 
2c Air flow capacity for recirculation duct based on 3-4 air changes/hr in room:

((____ft width x ____ft length x ____ft height)  (60 min/hr)) x 3 ac/hr =

((____ft width x ____ft length x ____ft height)  (60 min/hr)) x 4 ac/hr =

 

CFM

Range

CFM

  Air flow capacity for recirculation duct using 3-4 air changes per hour:

3 air changes/hour = 3 x (12ft x 50ft x 8 ft)/60 min/hr = 240 CFM

4 air changes/hour = 4 x (12ft x 50ft x 8ft)/60 min/hr = 320 CFM

 
2d Select air flow capacity for recirculation duct based on above criteria acceptable range is ___________ CFM (from items 2a, 2b 2c)   CFM
  Choose a recirculation duct capacity between 240-900 CFM. For this example, select 600 CFM.  
3 Cross-sectional area of re-circulation duct based on maximum 800-1,200ft/min air velocity along duct:

_______ CFM through duct/800ft/min = ______ft2

_______ CFM through duct/1,200ft/min = ______ft2

ft2

Range

ft2

  Cross sectional area of recirculation duct to achieve 800-1,200 ft/min air velocity in duct:

Minimize size with lower air speed along duct = 600 CFM/(800ft/min) = 0.75ft2

Minimum size with higher air speed along duct = 600 CFM/(1,200ft/min) = 0.50ft2

 
4a Choose an appropriate sized circular duct to achieve required cross sectional area:

Circular: diameter 1 = ((4x Area 1 ____ft2/3.14)) x 12in./ft =

                diameter 2 = ((4x Area 2 ____ft2/3.14)) x 12in./ft =

in. dia.

in. dia.

  For a circular duct to achieve the required cross-sectional area:

Diameter 1 = ((4 x 0.75 ft2/3.14)) x 12in./ft = 11.7in

Diameter 2 = ((4 x 0.50 ft2/3.14)) x 12in./ft = 9.6.7in

Therefore, either a 9 in or 10 in. diameter duct is acceptable.

Note: Larger ducts are quite acceptable and provide lower air speed through the duct, however they generally cost more and create more of an obstruction.

 
4b Choose an appropriate sized square duct to achieve required cross sectional area:

Square: side length 1 = (Area 1 _____ ft2) x 12in/ft =

              side length 2 = (Area 2 _____ ft2) x 12in/ft =

____x____ in.

____x____ in.

 

  For a square duct tot achieve the required cross-sectional area:

Side length 1 = (0.75ft2) x 12 in./ft = 10.4 in.

Side length 2 = (0.50ft2) x 12 in./ft = 8.5 in.

Therefore, either a 9 in or 10 in. square duct is acceptable

Note that these dimensions should be net with no framing members reducing the duct area.

 
4c Choose an appropriate sized rectangular duct to achieve required cross-sectional area:

If one side = ____in., other side is Area 1 ____ ft2 x 144in2/ft/12in = 

If one side = ____in., other side is Area 2 ____ ft2 x 144in2/ft/12in = 

12 x ____ in.

12 x ____ in.

____x____ in.

____x____ in.

  For a rectangular duct to achieve the required cross-sectional are:

If one side is 12 in., then the other side can be (0.75ft2 x 144in2/ft2) / 12 in. /ft = 9 in

If one side is 12 in., then the other side can be (0.50ft2 x 144in2/ft2) / 12 in. /ft = 6 in

 
4d Select desired duct size from 4a, 4b, 4c  
  Reviewing the calculations completed in 4a, 4b and 4c, there are a number of acceptable duct sizes that could be used. For this case, the designer has chosen a 10in. diameter circular duct, but a square or rectangular duct could  be substituted.  
5 Total area of air distribution holes ____ CFM air flow capacity through the duct/1,000 ft/min ft2
  The total area of holes required is: 600 CFM/(1,000ft/min) = 0.6ft2  
6 Choose hole size from Appendix B, ____in. diameter based on ____ft required jet distance in.
  Select hole size from Appendix B. Choose a 1.25 in diameter hole size based on a jet throw distance of approx. 11ft  
7 Number of holes required(____ft2 area of all holes)/((3.14/4x(____in.dia.)2)/(144 in2/ft2)) Hole
  Since each hole has an area of 0.0085ft2, then o.6ft2/0.0085ft2 = 71 holes required.  
8 Recirculation duct length: enter useable duct length leaving room for duct fan, entry of room air and duct transition if necessary. Ft
  Duct length limited to 48ft long to allow room for the fan unit and pick up of room air.  
9 Holes to be located along one or both sides of duct (depends where the duct is located and if air jetting is required in one or both directions) Side(s)
  Since room is narrow (12ft) and jet throw distance of 11 ft; select holes on one side of duct.  
10 Hole spacing (____ft duct length/(____holes/____sides)) x(12in./ft) in. on centre
  The hole spacing will be: 48ft/71 holes = 0.67 ft x 12 in./ft = 8 in. on centre.  

 

Circulation Fan Work Sheet

1 Floor area of room ____ ft room width x ____ ft room length Ft2
  The gross floor area of the room is 48ft x 250ft = 12,000ft2  
2 Total air circulation capacity based on 1-3CFM/ft2 of floor area

_____ft2 floor area x 1 CFM/ft2=

_____ft2 floor area x 3 CFM/ft2=

CFM

Range

CFM

  The range of total air circulation fan capacity required is between 1-3 CFM/ft2 of floor. This calculates to a range of 12,00-36,00 CFM. Generally, the designer will choose a circulation quantity in the middle of this range but may lean towards either extreme based on small, sensitive livestock or larger more tolerant animals being housed.  
3 Number of circulation fans based on individual fan capacities:

­­_____ CFM minimum total circulation/5,000 CFM/fan =

_____ CFM maximum total circulation/5,000 CFM/fan =

_____ CFM minimum total circulation/3,000 CFM/fan =

_____ CFM maximum total circulation/3,000 CFM/fan =

Fans

Fans

Fans

Fans

  The most common fan sizes used for internal air circulation have a capacity range between 3,000-5,000 CFM when operated at full speed (even though they are generally never operated at full speed through the three cooler seasons). Using this data and the total air circulation capacity range calculated in # 2, the number of fans required to meet each scenario can be calculated. The results indicate the need for 3-8 fans having an individual capacity of 5,000 CFM or the need for 4-12 fans with a capacity of 3,000 CFM each.  
4a For a racetrack type circulation pattern, minimum number of circulation fans based on maximum spacing or flow distance between fans of 100ft: _____ft barn perimeter/100ft = ____fans min
  For a racetrack type circulation pattern, locate fans no further than 100ft along the length of each side of the room. This will require a minimum of 6 fans to complete the racetrack travel path.  
4b For a racetrack type circulation pattern, minimum number of circulation fans based on maximum spacing or flow distance between fans of 60ft: _____ft barn perimeter/60ft = ____fans max
  For a racetrack type circulation pattern, locate fans no closer together than 60ft. If located every 60ft, 10 fans would be required to complete the racetrack travel path.  
4c For a racetrack type circulation pattern the acceptable number of circulation fans and their individual air flow capacity range between. (from above criteria 3, 4a,4b)

Minimum: ______fans @3,000-5,000 CFM

Maximum: ______fans @3,000-5,000 CFM

Min ____ Fans @ ____ CFM

Max ____ Fans @ ____ CFM

 

  From above calculations (3, 4a, 4b), the minimum number of fans for a racetrack type circulation pattern is 6 and their capacity ranges between 3,000 – 5,000 CFM each for a total 18,000-30,000CFM. The maximum number of fans is 10 with a total capacity of 30,000-50,000 CFM.  
4d For a racetrack type circulation pattern, choose a number of circulation fans and their individual capacity from the range determined in 2 and 4c (there are several acceptable choices) ____ fans @ ____ CFM

 

  From the above calculations (2, 4c), the designer of a racetrack type pattern must choose a number of circulation fans and their individual capacity. There are a number of acceptable choices. They include:

 

6 fans @ 3,000, 4,000 or 5,000 CFM each

7 fans @ 3,000 4,000 or 5,000 CFM each

8 fans @ 3,000 or 4,000 CFM each

9 fans @ 3,000 or 4,000 CFM each

10 fans @ 3,000 CFM

 

 
5a For across the barn type circulation pattern, minimum number of circulation fans based on 1 fan/2,500ft2 of floor area ____ft2 floor area /1,500 ft2 ____ fans

 

  Another style of internal air circulation is to direct the air across the width of the building. This is the preferred method for rooms wider than 50 ft. In some cases, air is all moved in one direction, while in others a criss-cross arrangement is used. For an across the barn type air circulation pattern, the minimum number of circulation fans is based on at least 1 fan/2,500 ft2 of floor area: 12,00 ft2/2,500ft2 = 5 fans.  
5b For across the barn type circulation pattern, maximum number of circulation fans based on 1 fan/1,500 ft2 of floor area _____ft2 floor area / 1,500ft2 ____ fans

 

  The maximum number of circulation fans is based on 1 fan/1,500ft2 of floor area: 12,000ft2/1,500ft2 = 8 fans.  
5c For across the barn type circulation pattern, the acceptable number of circulation fans and their individual air flow capacity range between: (from above criteria 3, 5a, 5b) minimum: ____ fans @ 3,000-5,000 CFM

Maximum: ____ fans @ 3,000-5,000 CFM

Min ____fans @ _____ CFM

Max ____fans @ _____ CFM

 

  From the above calculations (3, a, 5b) the minimum number of fans across the room type circulation pattern is five and their capacity ranges between 3,000-5,000 CFM each for a total circulation capacity of 15,000-25,000 CFM. The maximum number of fans is eight with a total capacity of 24,000-40,000 CFM.  
5d For across the barn type circulation pattern, choose a number of circulation fans and their individual capacity from the range determined in 5c (there are several acceptable choices) ____fans @____CFM
  From the above calculations (2,5c), The designer of an across the room type circulation pattern must choose a number of circulation fans and their individual capacity. There are a number of acceptable choices.

They include:

5 fans @ 3,000, 4,000 or 5,000 CFM each

6 fans @ 3,000, 4,000 or 5,000 CFM each

7 fans @ 3,000, 4,000 or 5,000 CFM each

8 fans @ 3,000 or 4,000 CFM each

 

 

 

Fan Design Work Sheet

1 Number of animals housed and minimum weight     Animals Weight
200 grow-finish pigs, housed in an all-in all out facility with pigs entering the barn weighing an average of 25kg/pig.        
2 Number of animals housed and maximum weight     Animals Weight
200 grow-finish pigs, housed in an all-in all out facility with pigs being marketed weighing an average of 110kg live weight.        
3a Cold weather ventilation rate for minimum weight animals from APPENDIX B   CFM/Animal
Cold weather ventilation rates range from 4-8 CFM/pig minimum depending on their weight.    
3b Cold weather ventilation rate for maximum weight animals from appendix b   CFM/Animal
Cold weather ventilation rates range from 4-8 CFM/pig minimum depending on their weight.
4 Warm weather ventilation rate for maximum weight animals from appendix B   CFM/Animal
The maximum recommended ventilation rate per pig is 90CFM/pig    
5a Minimum Ventilation rate for minimum weight animals = ____# animals x ______CFM / animal   CFM
Minimum cold weather rate with small pigs: 200 x 4 = 800 CFM    
5b Minimum Ventilation rate for maximum weight animals = ____# animals x ______CFM / animals   CFM
Minimum cold weather rate with large pigs: 200×8 = 1,600 CFM    
5c Minimum air flow based on 4 air changes per hr ____ l x ____ w x ____h x 4/60 (Interior Building Dimensions)   CFM
Minimum cold weather rate based on 4 air changes per hour for better air quality: 6- x 35 x 8.5 x 4/60 = 1,190 CFM    
5d Minimum air flow based on specific design criteria by consultant   CFM
Minimum cold weather rate based on specific design criteria by consultant eg. Certain level of air quality is desired.    
6a Maximum warm weather air flow based on animal numbers = ____# of maximum wt animals x ____ CFM/animal   CFM
Maximum warm weather rate with large pigs: 200 x 90 = 18,00 CFM    
6b Maximum warm weather air flow based on 1 air change per minute = ____ l x ____ w x ____h   CFM
Maximum warm weather rate based on 1 air change per minute. This rate normally extracts the animal heat sufficiently fast to prevent the room temperature from climbing more than 2 above outside. 60x35x8.5= 17,850 CFM    
6c Maximum air flow based on specific design criteria by consultant   CFM
Maximum warm weather rate based on specific design criteria by consultant eg. Certain level of air quality is desired.    
Fan Stage Selection Calculated Actual Chosen  
7a Stage 1 fan selection based on variable speed maximum Stage 1 capacity calculation:

Minimum cold weather CFM per minimum weight animals _____ (from 5a) x 3

    CFM
If the stage 1 fan is variable speed, its maximum capacity is chosen on the basis of its flow rate being 2-3 times larger than the minimum exchange rate required: Maximum capacity of the stage 1 fan based on minimum rate for small pigs: 00 x 3 = 2,400 CFM      
7b Stage 1 fan selection based on variable speed maximum Stage 1 capacity calculation:

Minimum cold weather CFM per maximum weight animals _____(from 5b) x 2

    CFM
Maximum capacity of the Stage 1 fan based on minimum ventilation rate for large pigs 1,600 x 2 = 3,200 CFM      
8a Stage 2 fan selection if variable speed maximum low speed capacity =  maximum Stage 1 capacity (7a or 7b)     CFM
If stage 2 is a variable speed fan: Maximum low speed capacity should not exceed the full capacity of stage 1 ventilation = 2,400 CFM      
8b Stage 2 fan selection if variable speed maximum full speed capacity = ≤ maximum Stage 1 capacity x 2     CFM
If stage 2 is a variable speed fan: The maximum high speed capacity flow rate should not exceed approximately 2 times the capacity of Stage 1 ventilation = 2,400 x 2 = 4,800 CFM      
8c Stage 2 fan selection if single speed maximum capacity =  maximum Stage 1 capacity (7a or 7b)     CFM
If a single speed fan is needed for stage 2 ventilation, its maximum capacity should not be more than the full capacity of stage 1 ventilation to follow the doubling rule and prevent overly aggressive staging = 2,400 CFM (for this example the single speed option is chosen)      
9 Stage 1 and 2 air flow subtotal= (7a or 7b) + (8b or 8c)     CFM
Once the room temperature has increased another couple of degrees, the stage 2 fan is also operating at full speed and the room has a total air exchange rate of their combined total (Stage 1 + Stage 2) = 7,200 CFM (calculated) and 7,500 CFM (chosen)      
10 Stage 3 fan selection maximum capacity =  Stage 1 and Stage 2 subtotal (from 9)     CFM
If temperature continues to rise Stage 3 ventilation is activated to reduce the rate of temperature rise in the room. Limit the maximum capacity of stage 3 to the cumulative total of stage 1 and 2 to follow the doubling rule. It is acceptable to select a fan that is less than this cumulative value, but not greater than. Even though a maximum of 7,200 CFM is calculated, using another 24in diameter single speed fan rated at 5,000 CFM is a good choice for Stage 3 ventilation.      
11 Stage 1,2,3 air flow subtotal = (9 + 10)     CFM
The total air exchange through this swine room is now the cumulative total of Stage 1, 2 and 3. 2,500 +5,00 + 5,000 = 12,500 CFM      
12 Stage 4 fan selection maximum capacity = ≤ Stage 1,2,3 Subtotal (from 11)     CFM
A further increase in temperature requires Stage 4 ventilation to be activated. Its capacity is any value up to a maximum of 12,500 CFM For consistency, assume another single speed, 24 in. fan with a capacity of 5,000 CFM is chosen.      
13 Stage 1,2,3,4 air flow subtotal = (11+12)     CFM
The air exchange rate through the room now totals 12,500 + 5,000 = 17,500 CFM (Stage 1 + Stage 2 + Stage 3 + Stage 4) Compare this flow rate with the maximum summer ventilation of 18,000 CFM required, and as calculated in #6, it is close enough and no further ventilation fan stages are required. The actual ventilation rate chosen calculates to 87.5 CFM per pig.      
14 Stage 5 fan selection maximum capacity = ≤ Stage 1,2,3,4 subtotal (from 13)     CFM
15 Stage 1,2,3,4,5 air flow subtotal = (13+14)     CFM
16 Stage 6 fan selection maximum capacity = ≤ Stage 1,2,3,4,5 subtotal (from 15)     CFM
17 Stage 1 through 6 airflow subtotal = (15 +16)     CFM
18 Stage 7 fan selection maximum capacity = ≤ Stage 1 through 6 subtotal (from 17)     CFM
19 Stage 1 through 7 air flow subtotal = (17 +18)     CFM
20 Stage 8 fan selection maximum capacity = ≤ Stage 1 through 7 subtotal (from 19)     CFM
21 Stage 1 through 8 total airflow = (19 +20)     CFM

 

Attic Ventilation Design Sheet

1 Building width   ft
  Building width is 50ft    
2 Building length   ft
  Building length is 100ft    
3a Eave Ventilation: Option 1 – continuous slot width along each eave/soffit from table 8.1   in.
  From Table 8.1 the required continuous eave/soffit opening for a 50ft building is 0.0in. (from column 2)    
3b Eave ventilation: Option 2 – number of holes in perforated soffit from Table 8.1 ____@____

____@____

# @ in. diameter

# @ in. diameter

  From Table 8.1, equip a perforated metal soffit, with at least 14 holes, each ¾ in. diameter per foot of eave or 8 holes at 1 in. diameter per foot of eave (columns 4 and 5 of Table 8.1).    
3c Recommended choice for eave ventilation (3a or 3b)    
  Choose to install a minimum 0.5 in. wide continuous slot along the soffits or use commercially available perforated soffit material with the required number and size of holes specified. Maximum Building Length Per Ridge Ventilator ( columns 6,7 and 8 from Table 8.1).    
4a Ridge ventilation: Option 1 – number of circular type ridge ventilators required ____ft barn length/ ­­____ft per unit (Table 8.1)   units
  100 ft long building requires 100ft/12ft = 9 round ventilators    
4b Ridge ventilation: Option 2 – number of 4ft long ridge ventilators required ____ft barn length/ ____ft per unit (Table 8.1)   units
  100ft/30ft = 4 peak ventilators each 4 ft long.    
4c Ridge ventilation: Option 3 – number of 10ft long vented ridge caps required   sections
  100 ft/18ft = 6 sections of 10ft  long vented ridge cap.    
4d Recommended choice for ridge ventilation (4a,4b,4c)    

 

Natural Ventilation Design Sheet

Side Wall Openings
1 Floor area of room ____ width x ____ length ft2
Since the recommended minimum sidewall opening for natural ventilation is based on a percentage of the floor area, the building length and width is multiplied together to calculate this value (24,000 ft2)
2 5% of floor area = ____ #1 x (5/100) ft2
5% of the floor area is 1,200ft2
3 Net available length of opening along each side of room ft
The available length of sidewall opened up for natural ventilation in this example is 200ft of the total 240ft building length.
4 Minimum clear height of opening required ____ #2 ft2/ ____#3ft ft
The minimum height of natural ventilation opening is calculated by dividing the required opening area by the available opening length (1,200 / 200 = 6).
5 Recommended opening height to allow for curtain material and operating hardware = #4 + appropriate allowance (2 ft or 0.6 m) ft
Allowing for the curtain bunching up at the bottom of the opening or rolled up on a pipe prevents the entire opening from being available for air flow. The extra height is added to the opening to allow for this type of obstruction. The wall opening calculation yields the minimum recommended opening size and some extra height is a benefit during hot summer weather conditions.
If Chimneys Used for Ridge Exhaust
6a Total area of chimney openings if single storey building ____#1 ft2 x (0.5/100) ft2
If chimneys are used for ridge exhaust, then lines 6-10 are calculated to select the appropriate number and size of chimneys.
6b Total area of chimney openings if loft are above stable ____#1 ft2 x (0.5/100) ft2
A larger chimney area is required if the chimney is going up through a high hay loft. This is a function of friction losses in these longer shafts and keeping sufficient warm air in the chimney to prevent the air from cooling off too much prior to reaching the peak. For the free stall barn, approximately 120ft2 of total chimney area is required.
7a Number of chimenys required, based on 1 / 2,000 ft2 of floor area _____ #1ft2/2,000ft2 #
7b Number of chimenys required, based on 1/50 ft or less of room length _____ L ft /50 ft #
7c Number of chimneys required based on other design criteria specified by the designer #
7d Select number of chimneys from 7a, 7b or 7c #
The number of chimneys required is based on a reasonable floor coverage area per chimney and spacing of chimneys along the length of the building. These calculations suggest a number of chimneys ranging between 5 and 12. A ventilation designer might choose to have a specific number of chimneys based on aesthetics or some specific air flow rate, and line 7c is provided for these special cases.
8 Resulting chimney spacing is _____ L  ft/#7d ft
Once the number of chimneys is selected, determine their spacing by dividing the total building length by the number of chimneys. Locate the first chimney one half of this distance from an end wall to have each chimney servicing equal floor areas and look symmetrical along the length of the roof.
9 Minimum area of each chimney is: ____ #6a or 6b ft2/ ____ #7d ft2
Since the total number and total area of chimneys is now known, the required area of each chimney is 120ft2/12 chimneys for 10ft2 each.
10 Recommended chimney size to achieve minimum area ft x ft
There are several chimney sizes and shapes that yield 10 ft2 of area for air flow. These calculations are based on guidelines for natural ventilation openings and achieving the precise square footage is not essential. While a rectangular chimney 2.5 ft x 4.0 ft (0.7m x 1.2m) is selected, many contractors have installed 3.0ft x 3.0ft chimneys on this type of building and achieved good ventilation success.
If Open Ridge Used for Exhaust
11a Minimum ridge opening width = 1 in./10ft of barn width (____width ft/10ft) x 1 in. in.
11b Maximum ridge opening width = 2 in./10ft) x 2 in. in.
11c Select desired width of ridge opening to use ranges between #11a and 11b in.
If an open ridge, rather than insulated chimneys, is installed to provide the peak exhaust requirements, calculate lines #11 through # 14. The recommended width of continuous ridge opening ranges between 1-2in/10ft of building width. For this free stall barn, the recommended width of continuous ridge openings ranges between 10-20in. a width of 11.25 in. is chosen to coincide with the width of 2in. x 12in. lumber as it could be used as a spacer and framing for the sides of the ridge opening.
12 Maximum length of open ridge = _____ length ft of building – (2x8ft) in.
Run the ridge opening the full length of the building, except within 8ft of each end wall. This prevents a down flow draft which develops near the end walls under certain wind conditions.
13 Vertical side height of chimney = 1.5-2.0 times opening width ____ #11c in. x (1.5-2.0) in.
Open ridges work better if they are equipped with vertical sidewalls 1.5-2.0 times as high as the opening is wide. For this building, the side wall height is between 17-22in. high. Depending on the material chosen these ridge sidewalls might be 20in high.
14 Minimum opening above each ridge sidewall if installing a flat roof = #11c in.
Most open ridges have a flat roof to prevent the direct entry of rain and snow. This requires the clear opening above each sidewall and under the roof structure to measure at least as much as the ridge opening width.

 

Dual Ventilation Design Sheet

Fan Portion
1a Number of animals housed and minimum weight. # lb
  The swine facility is filled with 1,000 pigs weighing approximately 25kg.    
1b number of animals housed and maximum weight. # lb
  Market weight of 115kg is achieved over a 100-day period.    
2a Cold weather ventilation rate for minimum weight animals (Appendix B) CFM/animal
2b Cold weather ventilation rate for maximum weight animas (Appendix B) CFM/animal
  The minimum ventilation rate for grow-finish pigs ranges between 4-8 CFM/pig depending on their stage of growth (Appendix B)  
3 Warm weather ventilation rate for maximum weight animals (Appendix B) CFM/animal
  The maximum ventilation rate for market weight pigs is 90 CFM/pig (appendix B)  
4a Minimum ventilation rate for minimum weight animals = ____# animals x ____CFM/animal  CFM
4b Minimum ventilation rate for maximum weight animals = ____# animals x ____CFM/animal CFM
4c Minimum air flow based on 4 air changes per hr ____length x ____width x _____ height x 4/60 (interior building dimensions) CFM
4d Minimum air flow based on other design specific criteria by the designer CFM
  The minimum ventilation rate for this room varies between 4,000-8,000 CFM depending on the size of the pigs. For improved air quality, maintain a minimum ventilation rate equivalent to 4 air changes per hour, equal to approximately 5,200 CFM for this room (not including the variable space located below the slats).  
5a Maximum warm weather air flow based on animal numbers = ____# of maximum wt animals x ____ CFM/animal CFM
5b Maximum warm weather air flow based on other design specific criteria by the designer CFM
5c Maximum air flow based on other design specific criteria by the designer. CFM
  The maximum ventilation rate for this room is calculated based on several different criteria. Based on 1,000 pigs, near market weight, provide 90,000 CFM. 80,000 CFM yields an air exchange every minute in the air space above the slatted flooring. Select an increased rate due to the under-floor manure storage. A line in the design sheet is provided for this option.  
6a Min mild weather fan capacity required based on 25% of summer requirement ____(5a,b,c) x 0.25 CFM
6b Max mild weather fan capacity required based on 50% of summer requirement ____(5a,b,c) x 0.5 CFM
  For dual ventilation, the fan portion accounts for 25% to 50% of the maximum summer ventilation rate to cover the air exchange rates between late fall and early spring. For his building, the fan portion calculates to a range between 22,500 – 45,00 CFM  
Fan Stage Selection Calculated CFM Actual Chosen CFM
7a Stage 1 fan selection based on variable speed maximum Stage 1 capacity calculation: Minimum cold weather CFM per minimum weight animals ____ (4a) x 2    
7b Stage 1 fan selection based on variable speed maximum Stage 1 Capacity calculation: minimum cold weather CFM per maximum weight animals ____ (4b) x 2    
  Stage 1 of ventilation (and often Stage 2) use variable speed fans so the minimum fan speed is adjusted as pigs grow and the outside weather changes. The total capacity of the Stage 1 variable speed fans ranges between 12,000 -16,000 CFM based on the minimum rates required to increase for warmer weather conditions (7a and 7b). This total rate is divided between several fans. Since there is a long-term manure storage located directly under the slatted flooring these fans extract the air from the room, via the slatted flooring and pit area. Four variable speed fans each with a minimum capacity of 1,000 CFM and a total capacity of 4,000 CFM, work well to cover the stage 1 ventilation requirements.    
8a Stage 2 fan selection if variable speed maximum low speed capacity =  maximum Stage 1 capacity (7a or 7b)    
8b Stage 2 fan selection if single speed maximum full speed capacity = maximum Stage 1 capacity x 2    
8c Stage 2 fan selection if single speed maximum capacity = ≤ maximum Stage 1 capacity (7a or 7b)    
  A basic design criteria for air flow rates is to never more than double the existing ventilation rate with each successive stage. The Stage 2 ventilation must not be any more than 16,000 CFM, but could be less and will be if variable speed fans are installed. If another 4 variable speed fans, similar to the stage 1 fans are chosen with an air flow range of 1,000 – 4,000 CFM each, then the Stage 2 minimum is 16,000 CFM (Stage 1) + (Stage 2 min) to total 20,000 CFM. Other fan choice can be made (e.g. 3 a 1,500-5,000 CFM, etc.). These fans are installed as pit fans.    
9 Stage 1 and 2 air flow subtotal = (7a or 7b) + (8b or 8c)    
  Once the Stage 2 fans are operating at full speed the total air exchange rate is 32,000 CFM.    
10 Compare actual total flow rate (9) with (6a) and (6b)

·       If larger than (6a), switch to natural ventilation right away or add one more stage of fan ventilation to get close to value of (6b)

·       If larger than (6b), switch to natural ventilation for additional ventilation.

   
  Comparing 32,000CFM with 22,500 and 45,00 CFM, the first 2 fan stages are in the acceptable range to switch over to natural ventilation and decrease the chance of drafty conditions.    
11 Stage 3 fan selection maximum capacity = Stage 1 and Stage 2 subtotal (9)    
  Stage 3 could be as large as 32,000 CFM but is not required. Adding 2 additional exhaust fans, each with a capacity of 6,000 CFM is sufficient.    
12 Stage 1,2,3 air flow subtotal = (9+11)    
  The total air flow capacity is now 44,000 CFM    
13 Compare actual total flow rate (12) with (6a) and (6b)

·       If larger than (6a), switch to natural ventilation right away or add one more stafe of fan ventilation to get closer to value of (6b)

·       If larger than (6b), switch to natural ventilation for additional ventilation

   
  Comparing 44,00 CFM with 22,500 and 45,00 CFM, the flow rate is very close to the maximum recommended exchange rate for the fan ventilation portion and any additional ventilation is accomplished with natural ventilation.    
14 Stage 4 fan selection maximum capacity =  Stage 1,2,3, subtotal (12)    
  No stage 4 fan capacity is required.    
15 Stage 1,2,3,4 air flow subtotal = (12+14)    
  No additional air flow is achieved with fan ventilation in this particular building.    
Air Inlets
16 Minimum air intake area based on 2ft2/1,000CFM (____(9,12,15) CFM/1,000) x 2 ft2 ft2
  Bring fresh air into the attic space to supply the ceiling air inlets used for the fan portion of the dual ventilation system. The required intake area is calculated on providing 2 ft2 per 1,000 CFM of fan capacity and yields 88ft2 for this building.  
17 Minimum length of air intake opening into building or attic (from building plans = ______ ft) ft
  Since both sidewall soffit areas are available for fresh air entry, a total of 360 linear feet (180ft/side) is used.  
18 Minimum air intake opening width required (____ft2/(____ft)) = ____ ft x (12in./ft) + (1in. for screening) in.
  Based on this length, the required opening width is calculated as 2.9 in. This opening is screened to prevent the entry of birds and rodents which requires approximately 1 in. added to the calculation to prevent any restriction on air entry. The recommended opening width along both soffits is 4 in. continuous.  
19 Maximum mild weather air inlet velocity = 500-1,000 ft/min based on width of room and sensitivity of animals housed ft/min
  Two rows of single-sided ceiling air inlets are installed in this building and a jet distance of 20ft is required, and entrance velocity of 1,000ft/min is chosen.  
20 Minimum ceiling air inlet area ____CFM/____ft/min ft2
     
21a Number of modular air inlets required based on 1 inlet/10ft of building length (____ft room length /10ft) inlets
21b Number of modular air inlets required based on 1 inlet/10ft of building length (____ft room length/10ft) inlets
21c Choose number of ceiling air inlets to install based on 22a and 22b inlets
  Based on the manufacturer’s rating, the number of modular ceiling air inlets required to provide the 44,00CFM of air is 37 units. Another criterion is to have one air inlet for every 10 ft of barn length to ensure uniform air delivery all along the room. This requires 20 inlets in each row, so 2 rows of 20 air inlets are installed yielding a total of 40 inlets.  
22 Total length of air inlet baffle opening from number of modular inlets or length of continuous slot inlet (____modular units x ____in.)/12in./ft OR ____ft of slot ft
  Each ceiling air inlet for this project provides 27 in. of air inlet baffle board (from the manufacturer’s literature), so the total length of inlet is 90 ft. In some situations, install a continuous baffle board, enter the total footage installed.  
23 Maximum air inlet opening (____ft2 inlet area/____ft inlet length) x (12 in./ft) in.
  The maximum air inlet baffle opening distance is calculated by dividing the total are area required (from 20) by the length of sir inlet installed (22). Multiplying by 12 yields the answer, 5.9 in. Since this air should not dump directly down on the pigs, the calculated opening is less than 8 in. If the required opening is more than 8 in., install more air inlets or install less total fan capacity.  
24 Minimum cold weather air inlet velocity = 500-1,000ft/min based on width of room and sensitivity of animals housed ft/min
  A cold weather air inlet velocity close to 1,00ft/min is chosen to ensure a high-speed incoming air jet that mixes well with the room air and carries across the ceiling a good distance.  
25 Minimum air inlet area ____ (4a) CFM/____ft/min ft2
  The minimum air inlet area required is calculated by dividing the minimum air flow rate (4a) by the desired air inlet velocity (24) to yield 4 ft2.  
26 Minimum air inlet opening (____ft2 inlet area/____ft inlet length) x (12in./ft) in
  The minimum air inlet opening is calculated by dividing the minimum fan capacity required (4a) by the total air inlet length (22). Multiplying this value by 12 gives the answer of 0.5 in. This value is easy to achieve with a cable actuator and automatic temperature control. If this value is less than 0.1 in., precise control is difficult to achieve. The designer may consider options like less total air inlet length or an internal air circulation system.  
  Side Wall Openings  
27 Floor area of room ____ width ft x ____length ft ft2
  The amount of side wall opening is based on 5% of the total floor area, the barn length and width is used to calculate the floor area.  
28 5% of floor area = ____ft2 x (5/100) ft2
  The total area of wall opening along each side of the building is 5% of the floor area which equals 500ft2 in this case.  
29 Net available length of opening along each side of room (from building layout) ft
  Looking at the building layout, the available sidewall length for a natural ventilation opening is 180ft (55m) divided into two, 90ft(27m) sections along each side of the building.  
30a Minimum clear height of opening required ____ (28) ft2/____ (29)ft ft
30b Recommended opening height to allow for curtain material and hardware = (30a) + appropriate allowance ft
  The minimum clear height of the natural ventilation sidewall openings is determined by dividing the required total area (28) by the available sidewall length (29) with the result equaling 2.8ft (0.8m). Provide an allowance for the curtain material itself or any operating hardware that can obstruct the opening and reduce its size. Add at least 0.5 ft (0.15m) or more to account for any obstructions. For this case, a 3.5ft (1.1m) high opening is recommended, but a 4ft (1.2m) opening would not be excessive.  

 

 

 

 

 

 

 

 

Tunnel Ventilation System Design sheet

1 Number of animals #
20,00 broilers for day-old chicks  to a market weight of 2.2kg.
2 Target maximum CFM (appendix B) CFM
Maximum conventional system uses 7CFM/bird or 14,000 CFM. Note this value equates closely to the net room available above mature birds(60 x 300×8) = 144,000ft3.
3 Target design velocity (Table 7.2 Design Parameters for tunnel ventilation) ft/min
Design velocity when the tunnel system is fully operating is 300ft/min (see table 7.2 and equivalent to barn length to ensure 1 air change per minute).
4 Barn cross section (____ft width x ____ft height) ft2
The barn cross sectional area is 60 ft x 9ft or 540ft2
5 Total tunnel CFM (#3 x #4) = (____ x ____) (Note: must exceed result from #2) CFM
To achieve the target 300 ft/min velocity, the CFM is 300 x 540 or 162,000 CFM. Since this exceeds the value calculated in #2, this is acceptable.
6 Target inlet velocity (Table 7.2) ft/min
The tunnel inlet opening is calculated on the basis of an air intake velocity that does not create an excessive static pressure drop for the exhaust fans. A target of 500ft/min is an acceptable value.
7 Inlet cross sectional area (#5/#6) = (____)/(____) ft2
The required total tunnel CFM of 162,000 is divided by the target intake velocity of 500 ft/min to arrive at 324 ft2.
8 Inlet width (barn width – spacing obstructions, etc.) (_____ ft width – ____ft) ft
The inlet width is determined by the total barn width less any clearance issues (e.g. corner support, studs, doorway). For this facility, there is a free span of 55ft after total obstructions of 5ft are deducted.
9 Required inlet height (#7/#8) (____)/(____) ft
The required inlet height is 324/55 or 5.9 ft. This is rounded off to 6 ft such that a total opening of 6ft by 55ft is provided for fresh air entry.
10 Inlet deflector spacing (Table 7.2) ft
A deflector system ensures the air is used most effectively. A spacing of 75ft is chosen, starting from the air inlet end.
11 Number of deflectors (____barn length/____interval)-1 #
The number of deflectors is the barn length of 300ft divided by the deflector spacing of 75ft less ones, for a total of three deflectors.
12 Deflector opening velocity (Table 7.2) ft/min
Each deflector is designed to bring the average air speed back up and ensure the air flow is closer to the birds.
13 Required deflector opening area (#5/#12)(____)/(____) ft2
The required area for air flow underneath each defector is calculated by dividing the total ventilation capacity by the chosen velocity, 162,000/500 = 324 ft2.
14 Maximum deflector length below ceiling (room height -1) – (#13/barn width) ft
Knowing the required clear area for tunnel air flow (#13), the room height and allowing for the fact that the birds occupy the bottom foot of the room, the maximum height of a deflector panel is calculated as shown. This calculation indicates that each deflector does not need to hang any lower than 2.6ft below the ceiling to avoid obstructing the tunnel air flow too much.
15 Target static pressure (Table 7.2) in. w.c.
For selecting the tunnel ventilation fans from a manufacturer, a static pressure drop of 0.08 in. w.c. is chosen to account for head winds, air inlet openings and defector panels.
16 CFM of tunnel fan chosen at design static pressure CFM
Choose an AMCA or BESS laboratories rated fan that moves 21,000 CFM @0.08 in. w. c. (48 in. or 59 in. diameter fan).
17 Number of tunnel fans (#5/#16) #
The required air flow of 162,000 CFM is divided by the 21,000 CFM per fan at 0.08in w.c. to give a total of eight tunnel fans for this broiler facility.

 

 

Appendix B Ventilation Rates

Type of Animal Ventilation Rate CFM/Animal
Cold Weather Warm Weather
Beef Beef calves <3 months 10a 120
Veal Calves 12a 175
Beef Feeder 15 300
Beef Cow (450kg) 20 400
Chickens Laying Hens 0.3 6.0b
Replacement Pullets 0.08-0.30 5.0
Broiler Breeders 0.40 8.0c
Broiler Chickens 0.08-0. 7.0c
Dairy Calves <1 month 10a 100
Calves 1-3 months 12a 120
Heifers 3-12 months 15a 150
Small Framed Cow (e.g. Jersey) 25 400
Large Framed Cow (e.g. Holstein) 40 600
Goats Mature Does and Bucks 8a 120
Kids 2a 25
Horses Small framed <400kg 20a 200
Large Framed >400kg 30a 300
Rabbits Doe and Litter 0.5a 15
Market Rabbits 0.1a 10
Sheep Ewes and Rams 10a 120
Feeder Lambs 3a 40
Swine Breeding/Gestating Sow 10 200
Farrowing Sow with Litter 15 400
Nursery Pigs 2-25 kg 1.0-3.0a 15-35d
Grower Pigs 25-60 kg 4.0-6.0 50-70
Finishing Pigs 50-120 kg 6.0-8.0 70-90
Turkeys Breeders 1.0-2.0 25-35
Broiler Turkeys 0-8 kg 0.08-0.60 20c
Heavy Broilers 8-12 kg 0.60-1.0 25c
Heavy Turkey Toms 18-24 kg 1.0-1.5 30c
a To have a reasonably good air quality, this minimum winter ventilation rate may need to be increased to ensure at least 3 and preferably 4 room air changes per hour.

b This summer ventilation rate may need to be increased to ensure at least 1.5 or preferably 2 air changes per minute during hot weather

c Ensure the summer ventilation rate is at least 1 air change per minute.

d Limit the maximum summer air changes to 1 per minute for sensitive livestock

 

Appendix C – ventilation Design Values
Air Intakes – all exterior ventilation openings into the building Provide at least 2.0ft2 per 1,000 CFM of ventilation fan capacity
Provide at least 2.2ft2 per 1,00 CFM if light restrictors placed on intake
Provide at least 2.5 ft2 per 1,000 CFM if evaporative cooling pads installed on intakes
Air Inlets – all through the wall or ceiling air inlet openings covered with an adjustable baffle board Provide up to 2.0ft2 per 1,000 CFM of ventilation fan capacity
Design incoming air speed for 1,00f/min (cold weather) down to approximately 500ft/min (summer), depending on time of year, size and type of animals – baffle board or equivalent inlet adjustment is made to suit the specific air flow required
Recirculation-Boosted Air Mixing Ducts Sizing Air flow capacity of 3 times the minimum cold weather ventilation rate
Air flow capacity of 0.5-1.5CFM per square foot of floor area
Air flow capacity equivalent to 3-4 air changes per hour
Maximum Duct Velocity of 800-1,200ft/min
Recirculation-Boosted Air Mixing Duct Air Jet Holes Hole jet velocity of 1,000ft/min
Hole size based on required jet throw distance
Hole Size (in.) Throw Distance (ft)
0.50 6
0.75 8
1.00 10
1.25 12
1.50 14
1.75 16
2.00 20
Ideal hole spacing is less than 12 in. on centre, however spacing up to 24in. on center is acceptable
Internal Air Circulation Fans Provide total air circulation capacity of 1-3 CFM per square foot of floor area
Provide 1 fan for every 1,500-2,500 square foot of floor area
Use a maximum spacing of 100ft for circulation fans (60-90ft preferred)
Limit individual fan full speed capacity to a range of 3,000-5,000 CFM for the three cooler seasons
Equip each fan with a variable speed motor to adjust flow appropriately
Entrance Velocity of Inlet Air In winter, design for 800-1,000ft/min. If less air throw distances are desired for smaller rooms, consider an inlet velocity of 600-800ft/min
In summer, design for 500-600ft/min
Natural Ventilation Sidewall Opening Provide a minimum opening of at least 5% of the building floor area along each side of the building.
Natural Ventilation Open Ridge Width of ridge opening is approximately 1-2in./10ft of barn width (25-50mm/3m)
Chimney sides with a height of 1.5-2.0 times the ridge opening width increases the draw of air from the building
A flat roof over the ridge opening, which clears the top of the chimney by at least the width of the width of the opening, reduces rain entering the barn without compromising exhaust air flow.
Stop open ridges 8ft (2.4m) from both ends of the barn to prevent downdrafts.
Chimney Sizing Use a minimum of 0.5ft2 (0.05m2) of chimney area for every 100 ft2 (10 m2) of floor area for a single storey barn.
Use a minimum of 1 ft2 of chimney area for every 100ft2 (10m2) of floor area for a bank style barn where the chimney passes through the mow area
Recommended 1 chimney for every 2,000 ft2 (190m2) maximum floor area.
Do not locate chimneys further apart than 50 ft (15m) Maximum with 20-40ft (4-12m) being ideal

 

Appendix D T-tables

Approximate Heating Requirements for Poultry – Well Insulated Building, Dry Litter Conditions Ventilation Rates as Listed
Type of Bird Minimum Ventilation Rate (CFM/bird) Supplemental Heat (BTU/h/bird)
-20 -10 0 10 20
Broiler Chicken
Brooding 0.04 20 15 10 8 5
2 wks (0.5lb) 0.08 11 9 5 3 0
6 wks (3.7lb) 0.30 8 0 0 0 0
10wks (6.5lb) 0.60 13 0 0 0 0
Broiler Breeder Flocks
Light Breeds 0.40 10 1 0 0 0
Heavy Breeds 0.50 20 8 0 0 0
Laying Chickens
Replacement Pullets Brooding in Cages 0.04 12 10 8 6 4
2 wks 0.08 9 7 5 3 0
6 wks 0.30 2 0 0 0 0
Caged Laying Hens 0.40 0 0 0 0 0
Turkeys
Brooding 0.06 30 24 20 15 10
2 wks 0.12 20 15 10 6 2
8 wks 0.40 10 2 0 0 0
14 wks 0.70 5 0 0 0 0
18 wks 1.00 60 25 0 0 0
22 wks (17lbs) 1.3 84 42 0 0 0
Turkey Breeder Flocks
Light Hens (13 lb) 1.00 60 30 2 0 0
Light Toms (20lbs) 1.30 90 55 10 0 0
Heavy Hens (17lb) 1.00 70 35 2 0 0
Heavy Toms (28lb) 2.00 140 90 30 0 0
Approximate Heating Requirements for Swine – Well Insulated Building, Ventilation Rates as Listed
Type and Size of Pig Minimum Ventilation Rate (CFM/pig) Supplemental Heat (BTU/h/pig)
-20 -10 0 10 20
Gestation/Breeding Area 10.0 500 250 0 0 0
Farrowing Room (Sow and litter) 17.0 1,000 600 200 0 0
Weaning Pig Room
4kg 1.3 225 180 130 90 60
7kg 1.7 170 120 75 60 45
14kg 2.2 110 70 30 10 6
21kg 2.5 50 25 0
30kg 3.0 0
Grow-Finish Room
Approximate Heating Requirements for Calves – Well Insulated Building, Ventilation Rates as Listed
Size of Calf Minimum Ventilation Rate (CFM/calf) Supplemental Heat (BTU/h/calf)
-20 -10 0 10
Warm Calf Nursery (room temp. 10 – 12℃)
Avg. 80kg 10 1,500 1,000 500 0
Veal Calves (room temp. 10-12)
60 kg 8 700 350 0 0
80 kg 0 600 250 0 0
100 kg 12 450 100 0 0
140 kg 15 300 0 0 0