With profits returning to the hog industry, producers with older facilities are making plans for repairs this coming summer season. I’ve talked with a number of producers this past week who have older curtain sided finishing barns who are planning on replacing the roof steel on the south side due to corrosion issues, especially on the SW quadrant of the facility.
If you are one of these producers, now is the time to re-evaluate your ventilation system needs. The reason the SW corner of the barn has rusted roof steel is that most likely your ventilation system only has 20-25 cfm/pig total fan capacity. This generally means the curtain must open with big pigs in the barn when it is relatively cold outside for heat relief in the barn. This results in steam condensing on the roof steel and soffits. Not only does moisture condense on the steel, but also all of the gases and dust that are in the exhaust air.
Most newer curtain sided barns now have 35-38 cfm/pig total fan capacity. This means the barn stays in mechanical ventilation longer and it is much warmer outside when the curtains need to open for heat relief. As a result, there is less condensation and depositing of corrosive materials on the roof steel and soffits.