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Deterioration of Trusses and Roof Systems of Livestock Farm

Buildings

By Yves Choinière

Ing., agr., P. Eng.

CSBE: 08-117

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Introduction

Deterioration of steel and wood components of farm building– Well known– Documented

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Case study

#1: Finishing swine barn, Ontario– Power-natural ventilation versus 100 % natural

ventilation #2: Nursery-finishing, Ontario

– Mechanical ventilation #3: Finishing swine barn, Quebec

– 100 % natural ventilation #4: Pullet rearing barn

– Mechanical ventilation

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Case #1: Finishing swine barn

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Case #1: Finishing swine barn

Barn A– Power-natural ventilation, 1996– Winter pit fans– Modular ceiling air inlets– Deep pit over slatted floor– Summer natural ventilation

Barn B– 100 % natural ventilation, 1995– Similar to barn A

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Table of results, power-natural 1996

November 21, 2007

Exterior T° = 5°C, rain

Attic measurements In-barn

T° 6-7° C 15-16° C

R.H. % 60-65 % 80-85 %

NH3 2-4 ppm 15 ppm

CO2 600-700 ppm 3 000 ppm

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Table of results, 100 % natural 1996

Attic measurements In-barn

T° 6-7° C 15-16° C

R.H. % 70-75 % 70 %

NH3 N\D 15 ppm

CO2 400-500 ppm 3 000 ppm

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Observations

Attic space contamination from the barn to the attic by :– Modular air inlets– Fan exhaust– Eave openings– Vapor barrier failure

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Case #2: Nursery-finishing barn

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Case #2: Nursery-finishing

Mechanical ventilation– Ceiling modular air inlets– Sidewall fans– Open eave

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Table of results, 1997-1998

Attic measurements In-barn

T° 7-8° C 21-22° C

R.H. % 75-80 % 70-75 %

NH3 6-7 ppm 16-17 ppm

CO2 700-800 ppm 2 800-3 000 ppm

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Observations

Attic space contamination :– Modular air inlets– Fan exhaust– Eave openings– Vapor barrier failure

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Case #3: Finishing swine naturally ventilated barn

Natural ventilation– Alley scrappers– Eave openings– Attic ventilation

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Observations

Eave opening desing; minimum space Vapor barrier Chimney vapor tightness Ridge ventilator, snow + rain

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Case #4: Pullet rearing barn, 1976

Sidewall air inlets without attic contact Sidewall fan exhaust with wind stoppers

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Conclusion

Ceiling modular air inlets– Risk of attic backdraft– Sealed or negative pressure

Sidewall exhaust fans– No eave openings above winter fans– Fans with winter hoods– Eave opening desing

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Conclusion

Attic ventilation– Ridge ventilator– Eave openings, winter and summer– Fire stops

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Aknowledgements

Greg Zimmer, Ontario André Lafrance, Quebec

VicWest steel products