Engineering Your Farm
Engineering Your Farm
Swine Barn Winter Readiness
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Tony Mensing and Brett Ramirez discuss the importance of preparing swine barns for winter. Key steps include ensuring equipment functionality, particularly fans and heaters, and maintaining a tight barn to prevent air leaks. Regular maintenance and checks are essential for effective winter ventilation.
Winter Ventilation Checklist AE 3553B
This podcast is produced by the Iowa State University Extension and Outreach agricultural engineering team. I'm your host, Tony Mensing, field agricultural engineer, alongside my guest co host, Dr Dan Andersen, associate professor in the ag and biosystems engineering department. Welcome to another episode of the Engineering Your Farm podcast. So very excited to have a extremely knowledgeable guest with us.
Brett Ramirez:My name is Brett Ramirez. I'm an associate professor in the Department of Agricultural and biosystem Engineering here at Iowa State. I also serve as the Interim Director of the Egg Industry Center, and I have a wide range of expertise related to pig and poultry facilities and ventilation systems.
Tony Mensing:Yeah. Thank you so much for being with us, expert for sure in this space. So lucky to have you today, and we're going to pick your brain a little bit about swine barn ventilation as we're looking towards getting to these colder months. And where do you want to start?
Brett Ramirez:I'd say, let's start with getting the barn ready for winter.
Tony Mensing:Yeah, that's something in and takes more time and deserves more effort then, I think, gets credit sometimes, to look towards what we can do to get our barn in a good place. What's one of the first things that you would would have folks kind of take a look at?
Brett Ramirez:I'd say first couple things is make sure all the equipment is functioning correctly, just making sure our fans are clean operational, and we manually verify those fans. So actually go into the controller, hitting manual switches, making sure that they're turning on and off, or, you know, ramping as they're supposed to the variable speed settings seem reasonable, and just really making sure that equipment's ready to inspect heaters, brooders, the building envelope for construction integrity, soffits, you know, all that dust and debris accumulates in the soffits, and we want to make sure those are clean, because we're going to be pulling most of the air this winter through those soffits, so that needs to be a effective opening to get air up into the attic. Also, going back on the construction integrity, is just making sure the barn is tight. The best chance of success for minimum ventilation is having a really nice and tight barn. You know, any of the noticeable gaps, you know, make sure those are sealed so like under the door, curtain holes, you know, pump out covers are properly seated, and just making sure that that barn as tight as possible, so that all the air that we're bringing in is going through our planned ceiling inlets and getting the good air distribution that we need all winter in the low ventilation rates.
Tony Mensing:Yeah, that makes sense to me that if we're going to be trying to control that air flow, especially at those lower rates, that we want to make sure that we're directing that air in and and out where we want it to go. On the topic of cleaning the inlets and the fans and soffits, how much difference can that make to a system as we're talking about ventilation? So if, if I don't clean my fan, how much am I giving up?
Brett Ramirez:It gets a little tricky. There's a some old data that suggests, like an eighth of an inch of dust can reduce fan performance between 20 to 40% and so that'd be more on larger fans. But otherwise it's it's a little hard to quantify, but it can have a pretty major impact, just because that's just more restriction, and the fans got to work a lot harder against dust and the accumulation of things in the housing, the shutters, props, and so it just can have a pretty negative impact, especially when we're at the low rate and we're not moving a whole lot air. So if it's dirty and it's dirty and it's underperforming, that's going to lead to a worse environment inside the barn.
Tony Mensing:Sure. Kind of on that note, as far as not moving a lot of air, just for review, as we're looking towards winter ventilation, what, what are we actually up against? So we're moving kind of a minimum ventilation amount of air. What are we actually trying to accomplish in those barns?
Brett Ramirez:Yeah, our main goal in winter is to control the relative humidity inside the barn. So our usually recommendation is to keep it less than 70% targeting more to the 60%, 65% relative humidity inside that room and promoting good air distribution so that cold air comes in, it stays along the ceiling for as long as possible, so it has a chance to warm up before it then kind of gets down to the pig space, and then diffuses out and then through our fans. So it's really about we want to control moisture, provide a good, well mixed environment, and make sure our air change rate is acceptable.
Tony Mensing:Yeah. So along with that, we have to be concerned about temperature in those barns, right?
Brett Ramirez:Yeah, and that's usually pretty achievable, because we use forced air heat for the general airspace, which is, you know, adequately maintains the temperature inside the barn. And then if, you know, we have smaller pigs, if it's in a ween to finished barn, we'll use brooders to kind of prevent a nice, warm, micro climate for those pigs. And you know, as we're talking about heat with good air distribution, you know, it'll improve our heater operation and not use excess heat, because we're not having cold spots inside the barn where the temperature sensors might not be in the best spot, which can lead to inefficiencies. Yeah. So the important thing is, we have to use heat because we have to ventilate. And so, you know, somewhere between 80 to 90% of the heat loss through the barn is going to go out through the fan. It's important to keep and really make sure our controller settings are correct. You know, looking at the heater on, off temps or the offset depends on what controller you have, because that's where we have the probably greatest opportunity of making sure that heater is going to operate the most efficient, and we don't lead to the min vent fan ramping up, or the second or first stage fan turning on and just exhausting all that heat from the barn. Bubble wrap can help it. You know, it's going to provide another barrier from that cold curtain, which has a pretty low R value. So it's not really probably going to add to the effective r value of that side wall, but it will help minimize drafts. Probably help, you know, with leakage to some extent. But just remember, we need to keep a little gap up at the top, because if we do lose power and we have a curtain drop on the side, we need to be able to effectively get air in that barn in an emergency situation.
Tony Mensing:Um, looking at it from an economic standpoint, we can ventilate extra in the winter, but if we're adding heat back into that barn to maintain our pig space in a comfortable, productive environment, we're giving up dollars to be able to do that.
Brett Ramirez:Yes, you know, we need to maintain the proper desired room temperature for those pigs to, you know, optimize their performance, but we need to do it efficiently. Propane is high, and we want to make sure that that heat we're using is being effectively distributed, and the ventilation rate and distribution is also good, so we can keep that environment in terms of gasses, moisture and temperature uniform and where we want it to be all winter.
Tony Mensing:Kind of from that standpoint, I guess if we're thinking difference from summer to winter ventilation. Do you think that people struggle more with operating their facility in a productive manner? More so in the summer months, when we're trying to remove more of that heat, or more so in the winter months, where we may not know how inefficient we're operating that barn if we don't do a good check, like you just said, on where our fans are cutting in and out and and how we're ventilating versus heating.
Brett Ramirez:I think during the more stable outside conditions, the ventilation system is a little bit more easy to manage because there's not as much going on, per se. So actually, I find the spring and the fall to be the tougher times of the year to get ventilation right, because as we're talking about getting the barn ready for winter, which is going to mean winterizing certain things that aren't now going to be able to operate. So if we switch off our tunnel fans, or we cover our tunnel fans, which they should both be done together, and all of a sudden we hit, you know, in the low 80s, on one of these random days, we're going to need more air moving capacity, but it's not available because we've winterized and don't have access to that. So that's where you can lead into a little bit more dynamics in the barn, in these transition seasons, because of the outdoor temperatures, you know, all over the board in terms of highs and lows, and so you know, when you make those decisions to winterize is challenging because of the way the temperature swings here. So that's why I think there's just a lot more going on with the outside conditions that lead to a little bit more challenges with ventilation versus when it's, you know, consistently below 30, 30-40, degrees outside, or consistently above 70 degrees outside, there's just not as much happening, and it's kind of a more stable operation of the system.
Tony Mensing:From a barn management standpoint, what do you recommend for people to do? As far as I obviously want to pick the perfect day to make my change if I'm going to with those tunnel fans, etc. But what do you recommend people to do, look towards some sort of forecast, or pick a day on the calendar, or go with what feels right? What?
Brett Ramirez:Yeah, that's a tough one, and it's just going to be really varying between producers. You know, there's one kind of rule of thumb, is when the temperature is consistently below about 50, that maybe start to trigger the winterization steps. And you know what, you know, average temperature 50. So you can interpret that a couple different ways, but that's usually around 50 would be the temperature that I'd start making decisions. So it'd probably be, you know, your daytime highs are, you know, in the low 50s, pretty consistently,
Tony Mensing:Sure, yeah, but it's hard to know based on uh calendar or even what we think is coming the next couple days, for sure, what things will be like. Appreciate the insight on on those couple things you mentioned, uh, tunnel fans, what? What other kinds of things besides operate and verify your minimum, vent systems. Are we doing as we're looking towards winter?
Brett Ramirez:Look at things like using bubble wrap if you got the time and resources to put it up? Turning off tunnel fans and putting on a solid cover of the plastic behind the shutters is always good, just again, cut down on the leakage coming through the shutters of the unused fans that we know aren't probably going to operate for three months during the dead of winter, verifying controller settings, and like I mentioned on the heater settings, motor curves in the controller, because that's going to be used quite a bit to adjust the speed of the min vent fans, and just kind of making sure if we've got our set point curves and other settings are in the right spot, that makes sense for winter.
Tony Mensing:Sure, as we think towards those min vent settings, lots of days in Iowa, we can have a pretty brisk wind. Do you have any recommendations for folks where we're looking at a facility running at min vent and can have a strong wind blowing against that fan. Is there something that people should do?
Brett Ramirez:Yeah, I've seen a few different things be done. One example is some people, if they have the ability to close the north facing soffit that just prevents a lot of air being pushed up into the attic, and also helps with blowing snow going up into the attic. Otherwise, like a headwind on a fan, there's not too much you really can do about it, but that's where making sure we have the right motor curve and the right minimum speed punched into the controller, and having that fan clean so it has its best chance at performing the way it should, even with a head wind on it. But they have diverters, or some farms just don't put pit fans or sidewall fans on the north side, so they just exclusively use the ones on the south side, so they're not exposed to that direct prevailing wind in the wintertime.
Tony Mensing:You mentioned snow working its way into the soffit. Do you have any tips or advice for people on a snow front?
Brett Ramirez:Like I mentioned, you can, you know, block them. They have some other ones that have like a like a j channel lip that also helps with when that snow whisks up the side of the building, to keep it from going up into the attic, and just making sure, if we do get big drifts or anything, that somebody's actually able to get outside and inspect the pit fans still and make sure that they're still working, even though that's a pretty miserable task on some of our winter days. But that's about the only good way to verify, or if it's you have a more advanced controller, you can always look at the current being pulled by the fans and make sure that they're actually still, you know, operating within the range of current you expect, and they're still on.
Tony Mensing:Sure, verify that things are where you expect them to be for the situation. Other things is, we're thinking colder months are there are the things that we use, systems that we use in the summer we need to address as much or more so than just looking at what we're going to do with the ventilation system for our min vent winter type settings?
Brett Ramirez:Yeah, if you're a sow farmer, one of the few finishers that have, like, an evaporative cooling pad, that'll need to be winterized, just because those are exposed to the outside. So those will be need to be drained and properly winterized so we don't have pipe trees. Otherwise, there's not too many other things that need to get done, other than really making sure equipment's functioning correctly, cleaned and barn's nice and tight.
Tony Mensing:As far as making sure that that barn is tight, like you've talked about a little bit, you mentioned a handful of places that you want to check. Can you just go through that list of want to do a once over on the whole facility, I'm sure, but places in particular that producers may not think to check?
Brett Ramirez:The ones that are hard to check are the ones that are probably not worth the time to investigate. So there's still a lot of leakage that comes in through where the side walls meet the ceiling, end walls meet the ceiling. There's just some really hard parts that just can't really be verified easily. So those are probably not worth the time. So that's why I try to stick with the the easy ones, which would be, you know, gaps under doors, leaking door frames, holes in the curtain, end pockets, pump out cover lids and actual fan housings on the pump out cover unused tunnel fans, where the shutters are, be about some of the easy ones to take care of.
Tony Mensing:Mostly, we're just looking to maintain those back to kind of their original condition, right? So we don't have a new or un engineered opening to let the air through that structure, right?
Brett Ramirez:Yep, we want the most air we can to go through the planned openings, which are the ceiling inlets. And you know, every hole or crack orgap that allows outside air to come in is not going through a ceiling Inlet, which makes it harder to get a good air speed at the ceiling inlet. Poor air speed at the ceiling unit results in that cold air coming in, dropping and kind of making a mess underneath that inlet.
Tony Mensing:Can you expand on that just a little bit? So inlets are extremely critical in maintaining a good environment inside that barn. So walk through the physics on why that is a little bit.
Brett Ramirez:Yeah. So when we have a temperature gradient between the outside of the barn and the inside of the barn, we need that cold air to come in. It's going to come out of the inlet. We're hoping for about 600 feet per minute at min vent, and closer to 800 in the subsequent stages. So as that cold air comes in, it needs enough velocity or momentum to travel along that ceiling. And so as it's traveling along, it's going to be warming up, and then, you know, picking up moisture. So we're expecting it to go about 12 to 15 feet. And so one easy way to check is, you know, you can feel it yourself, or you can tie a string or a survey tape, you know, at that 12 foot mark, and verify that it's actually in a little breeze. And so then as that jet comes in, it's going to start to expand, and then it's going to hopefully, kind of diffuse in the pig space, or not looking for drafts, especially in wintertime, because that air can still be quite cold as it comes in.
Dan Andersen:So as you think about a farmer checking for that, certainly the string is a great tip. Some of it's just walking through and looking for drafting areas. What are some animal behaviors we should look for, for uncomfortable conditions in the barn?
Brett Ramirez:Yeah. So the easy one is, if you're just placing pigs in wintertime, is where their dunging pattern is first established. Because if it's, you know, within about four to six feet of the inlet, you know that that cold air is just coming down, because that's going to be the least desirable spot in the pen. Also, they'll just tend to avoid certain areas. So if you notice them just favoring certain spots, especially when they're lying, probably suggests that it might be too cold there or too drafty. And obviously, with smaller pigs, they're going to start to huddle and pile to some extent if they're that cold, which could be, again, an indication the air temperature might be too low, or there might be a draft somewhere that the pigs just can't get away from.
Tony Mensing:Is there a better resource than the pigs themselves, as far as just kind of a visual as you're in the barn looking to verify that the systems are functioning like they're supposed to be?
Brett Ramirez:Yeah, the pigs, you know, the best resource, but it's just hard to look at them without disturbing them. Once you open that door, they all get up real quick. So pigs the best, but then, you know, having, like a portable weather meter that can measure temperature and humidity and air speed is great, because then you can measure your airspeed at the inlet to verify, you can check your relative humidity and your temperature in different spots in the barn.
Tony Mensing:As far as inlets, again, on a maintenance standpoint, they should function like they're intended to function. Are there maintenance issues? Do you see routine issues with inlets that are something to kind of keep at the forefront for what folks might want to be watching for as we're making sure they're clean and working like they're supposed to?
Brett Ramirez:Yeah, so with inlets, the key parts are making sure the housing is still intact. A lot of builders are using a lot of caulking around that the box, which is good usually, but I usually see that starting to dangle off. So again, that's another leakage point. So just making sure the inlets, the piece of plastic itself is in good shape. It's not hanging, it's correctly fastened and caulked. And then we also have to look at making sure that we get them all at the right opening so they need to go through manually, run shut, you know, strings tightened up, making sure then the travel distance is good, that we're going to the controller, and verifying the run open and closed times, making sure that's getting inputted correctly, whether it's done automatically or manually, making sure the strings are there and the zoom and nuts are also present, because sometimes those disappear over time. Actuator might need to be greased if it is actuated, and then again, just verifying its function is traveling how it should.
Tony Mensing:Sure, as we think through using the controller to do those verifications, from the controller standpoint, are people operating different scenarios throughout the year, as far as how they set up their controller. Or do you recommend people to have kind of a switch as we transition into winter or should be set up to work all year long?
Brett Ramirez:There's been kind of two schools of thought on that there. There are some recommendations that have a little bit different settings for winter and summer. That, again, requires a manual change in the system, which, again, as we talked about earlier, when do you actually make that change? So do you want to extend the bandwidth in wintertime a little bit? Do you want to adjust in the room temperature a little bit? There has to be a decision point when that goes into effect, and that's what makes it kind of hard. And then somebody's got to also remember come springtime, to set it back to the summer conditions and vice versa as we go out throughout the year. So some of them just kind of lean towards one set of settings all year, because it then kind of minimizes the chance of things not being programmed correctly each season. It kind of just depends on what the producer is more comfortable with.
Tony Mensing:Sure, yeah, that makes good sense to me. What other tips might you want to share from a ventilation standpoint?
Brett Ramirez:Verify equipment and make sure the barn is nice and tight and controller settings are the top three I would focus on and set you up for good chance at success of ventilating during winter.
Tony Mensing:And Iowa State University Extension outreach And yeah, appreciate you sharing your expertise with us today, has a great publication to help people at a winter ventilation checklist. It's publication AE3553B, that's available on the Iowa State University Extension store. So a lot of the things that you talked about are on that checklist, and this has been a really good refresher for me. As far as thinking through what we're going to look at, a lot a lot of things to keep in mind. Brett. Fantastic resource on all things. As far as production facilities are concerned, once again, I'm Tony Mensing field agricultural engineer with Iowa State University Extension and Outreach based in southwest Iowa, and on behalf of the whole ISU Extension Outreach Ag Engineering team, I'd like to thank the listeners for tuning into this episode, and look forward to having you back for more Engineering Your Farm podcasts. Thank you. This institution is an equal opportunity provider for the full non discrimination statement or accommodation inquiries. Go to www.extension.iastate.edu/diversity/ext.