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Extension > Agriculture > Dairy Extension > Facilities > Ventilating Calf Barns with Tube Systems

Ventilating Calf Barns with Tube Systems

Kevin A. Janni

Published in Dairy Star April 2, 2010

Some dairy producers and heifer raisers are installing tube systems to help ventilate remodeled barns used for raising heifers. Important decisions need to be made when sizing and installing them. Additional decisions need to be made to complete the ventilation system.

Table 1. Airflow per tube (MWPS-32, 1990)

Tube diameter (inches)

Airflow (CFM)

8

210 - 280

10

320 - 440

12

470 - 630

14

640 - 860

16

830 - 1,100

18

1,060 - 1,400

24

1,850 - 2,500


Table 2. Airflow per hole (MWPS-32, 1990)

Hole diameter (inches)

Airflow
(CFM per hole)

1

2.7

1.25

4.2

1.5

6.1

2

11

2.5

17

3

24

The simplest tube system has an axial fan connected to a long plastic tube with holes distributed uniformly along the tube. The fan pushes clean fresh outside air into the tube, which exits through distribution holes along both sides of the tube. Airflow through the tube and out distribution holes is complex but simple systems are useful. Uniformly sized and distributed holes do not provide uniform air distribution; more air exits the tube at the closed end than the fan end.

Tube systems should be used to distribute clean fresh air taken directly from outdoors through a wall or out of the attic. Air for calves should never be taken from an area housing older heifers or cows. The air from older animals usually contains airborne pathogens and gases that can cause disease or respiratory stress in pre-weaned and weaned calves.

Tubes should not be used to recirculate or mix air in a calf barn. If the tube is allowed to recirculate air, it will collect dust and microorganisms in the bottom of the tube. While tubes can be cleaned, they are seldom cleaned enough to prevent disease transmission to the next batch of calves.

Key tube system decisions include fan airflow rate, tube diameter and length, and number, size and location of distribution holes. The guidelines presented here are based on information in the Mechanical Ventilating Systems Handbook (MWPS-32) by MidWest Plan Service.

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