HOUSING PIH-32 PURDUE UNIVERSITY. COOPERATIVE EXTENSION SERVICE. WEST LAFAYETTE, INDIANA Building Materials and Equipment for Swine Facilities Authors Vernon M. Meyer, Iowa State University Gerald R. Bodman, University of Nebraska William H. Friday, Purdue University Reviewers L. Neil Burcham, New Mexico State University Robert M. Butler, University of Wisconsin Nevin Wagner, Manheim, Pennsylvania Producers who have invested in new swine facilities are often disappointed by the severe deterioration of their facili- ties after just a few years. Much of the deterioration could have been prevented if the producer had considered the corrosiveness of the environment within the facility and the pigs' destructive nature. These problems are more pronounced in enclosed facilities but can occur in all types of units. The most rapid deterioration takes place near the floor because of wetness, chemical corro- sion, and physical destruction. However, the effects can also be observed in other parts of the building, especially on unpro- tected metal. Rapid corrosion of metal is characteristic of facilities with a poorly designed ventilation system. See Pork Industry Handbook fact sheet PIH-60, Mechanical Ventilation of Swine Buildings. When planning your building, select materials that are insurable, corrosion-resistant, and durable enough to withstand the rugged pushing, rubbing and chewing activities of the pigs. Materials within the building but outside the pens are not as vulnerable to physical deterioration, but they can have a rela- tively short life because of corrosion. Materials along alleys will be subjected to physical abuse from the pigs and from moving equipment. Therefore, carefully select equipment and materials regardless of their intended use or location. Floors A good, high-quality concrete mix is necessary because manure acids corrode concrete. Solid floors should be made from a mix that will yield a 4,000 psi concrete (maximum of 6 gal. of water per bag of cement). Air entrained concrete should be used for all installations, especially where the concrete will be sub- jected to freezing temperatures. An alternative is to place a lower strength, less expensive concrete as a base and then add a higher strength concrete over the top as a wear surface. This is accomplished by placing a steel reinforcement mesh over a rough- graded layer of concrete and then adding a finish layer of con- crete. The savings in material cost should be evaluated in light of possible inconvenience during the placement of layers of con- crete and higher labor costs. If slats are to be used, they should be designed for corro- sion resistance as well as strength. Additional flooring design details can be found in PIH-53, Flooring for Swine. Walls Concrete and wood-frame are both satisfactory for exterior walls. A choice should be made after considering both construc- tion and maintenance costs. Consider also the work required to provide openings in the wall, such as for ventilation. Concrete is one of the most durable materials for walls that are subjected to animal and equipment contact. However, concrete has little thermal insulating value. Where warm interior tempera- tures are to be maintained, as for a farrowing or nursery facil- ity, additional insulation is recommended. In cold climates, insulation is also essential in growing/finishing buildings to prevent condensation and retain animal heat. In very mild cli- mates, concrete walls without insulation are satisfactory for some phases of a hog production facility. Sandwich panel construction is an effective means of provid- ing a durable interior and exterior surface and at the same time, improving the thermal efficiency of the wall. Sandwich panels are formed by placing a foam board insulation material within the wall during casting of the concrete. This can be done either with cast-in-place walls or precast, tilt-up panels. An alternative that can be used where animals do not have access to the outside of the building is to erect a concrete wall and apply a spray-on urethane insulation material on the outside. The insulation must be painted or otherwise protected to retard destruction by ultraviolet light from the sun. For added protec- tion, the foam should be covered with a 1/4-in. layer of spray-on plaster or gunite concrete. The result is a durable, thermally efficient, stucco-like wall. Wood-frame walls may be of conventional stud frame or post frame construction. In either case a wider range of materials is available for enclosing the exterior frame. Among the materials that have been used successfully are ribbed steel or aluminum; composition boards, such as particle board or hardboard; exterior plywood; and boards. As with all wall construction, both initial and maintenance costs, as well as useful life, should be con- sidered before deciding on the material to use. With either type of wall, stud or post, thermal insulation can be added easily. However, appropriate construction plans must be followed, such as planning stud or girt spacings to accommo- date standard widths of insulation materials. The range of insu- lation materials is broad and includes fiberglass blankets, pour insulation, foam boards and spray-on foams. Regardless of the insulation material chosen, an interior protective covering is necessary. Where walls are exposed only to personnel and will not be subjected to hog contact or vehicular traffic, the choice of interior covering materials would include the same materials as for exterior surfaces. The potential for both vehicular traffic and animal contact makes the use of the more durable interior coverings desirable. For occasional contact, such as along alleys used for hog move- ment, ribbed sheet metals, plywood, wood boards and composition boards are good choices. For continual contact, as in pens, the use of solid coverings hardwood, steel sheets or panels, or fiberglass-reinforced plastics (FRP) is recommended. Plastic mouldings used with FRP panels should be located at the pen par- titions or fastened very securely so as not to give the pigs a place to start chewing. The FRP material is also available in roll form in long lengths thereby reducing the number of possible joints. On wall areas above the reach of the animals (usually con- sidered to be about 4 ft.), most common building materials can be used. However, since sanitation is important in swine buildings, these lining materials should be nonporous and durable enough to withstand cleaning with a high-pressure water system. Ceilings The main requirements for a ceiling material are cleanabili- ty and corrosion resistance. Like wall sections above the hog contact areas, most common building materials can be used. Since roof trusses are usually spaced 4 ft. on center, the cost of any additional nailers required for installation of a particular ceiling product should also be considered as part of the ceiling cost. Materials such as ribbed metal can be attached directly to truss chords without additional nailers. Insulation and Vapor Barriers Where insulation is to be used, consider the purchase price, installation cost, required coverings, and thermal effectiveness. In measuring thermal effectiveness, it is recommended that insu- lation or ``R'' values as given by the American Society of Heat- ing, Refrigerating, and Air-Conditioning Engineers (ASHRAE) be used (Table 1). The high moisture levels in swine facilities require that appropriate vapor barriers be used. These are needed to reduce the movement of water vapor into a wall or ceiling. Allowing water vapor to move into a wall will cause condensation within the wall or ceiling assembly. The condensation will result in a lower R-value and possible destruction of the insulation material. In general, a 4-6 mil plastic (polyethylene) vapor bar- rier should be used with all insulation materials because, even with vinyl-clad foam boards, it is impossible to maintain all joints in a water vapor-tight condition. In all cases the vapor barrier should be located on the warm side (inside) of the wall or ceiling between the interior covering and the insulation. See PIH-65, Insulation for Swine Housing. Figure 1 illustrates the procedures of determining the R- value for a concrete block wall using the data in Table 1. Figure 2 shows how to calculate the R value of a ceiling. Figure 3 shows winter degree days, and Table 2 recommends minimum insulation levels for swine buildings. Mice, other rodents, and birds can seriously damage any type of insulation. See PIH-107, Controlling Rats and Mice in Swine Facilities. Use physical barriers to keep rodents out of build- ings. If ribbed metal is used for inside wall linings, the end openings of the ribs should be closed to prevent the entrance of rodents. A good rodent control program is essential since they Table 2. Recommended minimum insulation levels for swine build- ings. R values are for building sections. ________________________________________________________________ Recommended minimum R values __________________________________________________ Modified Supplementally Winter ``Cold'' environment heated __________________________________________________ degree days Walls Ceiling Walls Ceiling Walls Ceiling ________________________________________________________________ 2500 or less 6 6 14 14 22 2501 to 6000 6 6 17 14 25 6001 or more 6 12 25 20 33 ________________________________________________________________ Birds will destroy any exposed insulation. In some cases insula- tion is consumed directly as food, while in other cases it is used as a nesting location, a material for nest building, or sim- ply something to play with to pass the time. Consequently, cover the insulation and use an effective bird control program. Pen Partitions Pen partitions must be durable enough to resist rubbing, chewing and pushing by pigs and, at the same time, resist the corrosion of the environment and manure that comes into contact with them. The choice of materials depends partially on whether open or solid partitions are used and whether the partition is permanent or must be movable. Partitions are generally not insu- lated. The durability and general corrosion resistance of concrete makes it an excellent choice for partitions (minimum of 3500 psi; 7 gal. water per bag of cement is recommended). Concrete blocks, cast-in-place concrete, or precast concrete panels can be used (Figure 4). As with exterior walls, steel reinforcing bars or mesh should be a part of all concrete partitions to afford greater strength and to fasten partitions securely to the floor. When anchoring equipment to floors or walls, consider using stainless steel materials. Woods such as oak and southern yellow pine are fairly dur- able when used as pen partitions. A key requirement with wood is to restrict pigs from chewing it. Use tongue-and-grooved planks or well-matched planks to reduce access to edges where chewing can start. Softwoods will probably have a useful life of 2 years or less. Hence, their use should be restricted to temporary shelters. As with exterior walls, the life of partitions can be extended by overlaying the basic wood partition with such materi- als as fiberglass-reinforced plastics, steel sheets, or mesh. Where wood is in contact with the floor, ground or generally wet conditions, the use of pressure preservative-treated lumber is recommended for a longer use life. Both solid steel sheets and open welded wire mesh have been used for pen partitions with poor results. The most common steel panels use vertical rods or tubing. The life of these materials depends upon how well they can resist corrosion and flexing because of pushing by the pigs. To maintain partitions and reduce injury to pigs, all joints must be securely welded and protected from corrosion. Plain steel panels can be satisfactory if well protected with a long-lasting coating. The abrasive action of hogs wears away most post-installation coatings such as paint or epoxy. Also, once corrosion starts, it tends to work under the remaining coating and lift it away. Stainless steel is more expensive but might be worth the additional cost in permanent structures subjected to intensive use. Fiberglass panels with vertical bars are now available and appear durable. Solid plastic planks are available for use where a solid partition is desired or needed. Farrowing Stalls Material used for farrowing stalls includes stainless steel, aluminum, fiberglass, or galvanized and painted metal. Any metal near the stall floor is subject to extreme corrosion while parts of the stall's upper metal is subject to wear from the abrasion of sows rubbing. Aluminum stalls require nonmetalic insulating spacers to prevent contact with concrete or dissimilar metals, and galvanic corrosion. As with pen partitions, rusting will start quickly at unpro- tected spots on the steel stalls. A heavy galvanized coat helps but galvanizing will wear and corrode off in time. A quality steel farrowing stall will have all welds cleaned thoroughly, a good prime coat applied and a tough, durable, fin- ish paint coat applied over it. The life of all metal equipment will be extended with good ventilation to keep air in the hog house drier and lower in cor- rosive gases and by periodic cleaning and painting at the floor line. Plastic Pans When remodeling a farrowing or nursery unit, it is sometimes more practical to use the existing floor as is, and install plas- tic pans or trays under the slotted floor to contain the manure. Manure may be drained into a pipe that collects from each crate or deck and carries the manure to storage. In some cases a plas- tic auger can be used to convey the manure to the end of a row of crates or decks and then drain into storage. Some producers have indicated that at times, manure sticks to the plastic and must be cleaned with a high pressure cleaning system at cleanup time. An alternative is to partially fill the pan with water after each drain. This improves cleaning ability but requires handling of greater amounts of liquid manure. Plastic pans should be installed so that access is provided for hand scraping and pres- sure washing without having to spray through the floor. Roof Coverings The most common covering materials are plain or painted ribbed aluminum, galvanized or painted steel sheets, and asphalt shingles. All of these are satisfactory if good quality materials are purchased and properly applied. With galvanized steel, the use of sheets bearing a Zinc Institute, Inc. grade stamp is recommended. Outdoor exposure studies at The Pennsylvania State University revealed that sheets with a 2-oz. zinc coating and a ``Seal of Quality'' grade stamp required 15 years of exposure before the first signs of rust. Sheets with a 11/4-oz. zinc coating began to rust after 7 years. Sheets with less zinc per square foot than these industry stan- dards are available at lower cost and will have a correspondingly shorter life before the first signs of rust. It is not possible to determine the amount of zinc coating by visual inspection. Even where factory applied finishes are used, the heavier zinc coatings should be used. Galvanized and painted steel is sold on the basis of thick- ness or gage. Gages most commonly available are 28 and 29. Lower gage numbers indicate greater thickness. A choice should include consideration of required roof design loads in the area and the load-carrying capacity of the roofing sheets. Manufacturers' literature and local codes can provide the required information. In selecting aluminum roofing sheets the ease of installa- tion should be considered. The use of high-strength alloy sheets of less thickness might be a disadvantage since their greater brittleness tends to cause them to split rather than dent if hit too hard or stepped on improperly. Avoid the use of extremely long sheets because of changes in length with variations in tem- perature. This results in tearing out of nail holes, or bending or extraction of nails or other fasteners. Fewer roof-leakage problems are generally experienced where the length of roofing sheets is kept to 24 ft. or less. To prevent corrosion of metal roofing through galvanic action, it is imperative that the correct fasteners be used with each kind of metal. Also, galvanized and aluminum sheets should not be placed in contact with each other. Where it is necessary to mix galvanized and aluminum products, they should be separated by a nonmetallic intermediate material. When installing asphalt shingles, use at least 235-lb. shin- gles with self-sealing tabs. Regardless of the roofing material used, the limitations of its use as related to roof slope should be recognized. Plumbing PVC or similar plastic pipe is probably the most suitable for a swine building environment. Because of the corrosive atmos- phere within swine facilities, metal pipe should be used with caution. Copper pipe usually has a short life when exposed in a swine building. If galvanized or black iron pipe is used, some type of coating should be applied at the threads since this part of the pipe is most subject to deterioration and failure. In warm facilities, plumbing can be run overhead to reduce contact with animals and manure. Although overhead pipes can be used in cold buildings, such placement requires electrical heat tape and pipe insulation to prevent freezing. Consequently, in cold facilities underground plumbing is recommended. Where pipes are brought to the surface, they can be run through a large- diameter plastic pipe to reduce corrosion and provide easier maintenance. In cold facilities, built-in heating units are suggested where cup waterers are used. Nipple waterers (Table 3) generally do not require additional freeze protection beyond that provided on the pipe up to the nipple. In all cases, a durable high- strength cover is required over pipe insulation and heat tape to reduce damage by pigs and reduce the potential of electrocution of pigs. Adequate grounding of all electrical equipment is a MUST. Good-quality waterers should be selected to reduce mainte- nance costs, extend the use life of the waterers, and reduce water usage and manure hauling costs resulting from leaking valves. Table 3. Planning guide, nipple waterers.* _________________________________________________ Sow Pig weight, lb. and _____________________________ Item < 12 12-3030-7575-100100-240boar _________________________________________________ Height, in. 4-6 6-12 12-1818-24 24-30 30-36 Pigs/nipple litter 10 10 12-15 12-15 12-15 Min. flow rates, quarts per min. 0.2 0.2 0.4 0.5 0.67 1.0 _________________________________________________ * Install at least two waterers per pen. Locate waterers 14" apart for nursery pigs; 24" for larger pigs. This distance may be reduced some if the nipples are angled away from each other. Electrical This may be the most critical component of a swine building since corrosion can create conditions that increase the risk of fire and electrical shock. Electrical materials installed inside a swine building should be designed for damp or wet locations. Thin-wall metal conduit has a short life and should not be used. Fittings, outlet boxes and switches not designed for waterproof locations may create an unsafe condition after several years. If conduit is used, it should be plastic. Type UF cable with water- proof fittings is another option. If at all possible, locate the entrance box in a dry annex of the office room to avoid rapid corrosion. Only surface-mount boxes should be used, especially on outside walls. See PIH-110, Electrical Wiring for Swine Build- ings. In cold climates, problems can be reduced if all conduit is installed within the warm part of the building. When conduit extends from the warm building up into the cold loft or attic, condensation can occur and the resulting moisture can move back to a fitting and cause corrosion or electrical faults. If a posi- tive pressure ventilation system is used, be sure that no moist, corrosive air can be pushed into electrical boxes. As noted in the discussion on plumbing, grounding of all electrical equipment is a MUST. This applies to all switches, receptacles and appliances since wet floors increase the con- tinual threat of shock and possible electrocution of both person- nel and animals. All electrical equipment and wiring should be installed in accordance with the National Electrical Code. Check with your electrician or power supplier. Feeders A low-quality feeder (Table 4) will not last long in a hog house. The increased moisture level near the floor speeds up cor- rosion. The activity of the pigs causes rapid wear. The upper part of the feeder may last more than 10 years, but this helps little if the bottom has failed. When purchasing a metal feeder, look for stainless steel or cast iron bottoms. Wood feeders can be improved by covering the wooden trough with a more durable material such as fiberglass or metal. Plastic feeders resist corrosion and appear durable. As with plumbing and electrical lines, the running of feed conveyance equipment through a ceiling should be minimized to reduce the risk of moisture condensation and the loss of heat. Ease of adjustment in a feeder is as important as durabil- ity. If a feeder cannot be easily adjusted to prevent feed waste, it can easily cost its owner many times its replacement value. Feeders with flat bottoms reduce shelter areas for rodents and are recommended. Table 4. Feeder space. _________________________________________________________________ Pig weight, lb. Pigs/feeder space _________________________________________________________________ 12-15 2 25-50 3 50-120 4 120-240 4-5 _________________________________________________________________ o Reference to products in this publication is not intended to be an endorsement to the exclusion of others that might be similar. Persons using such products assume responsibility for their use in accordance with current label directions of the manufacturer. REV 12/88 (5M) ______________________________________________ Cooperative Extension Work in Agriculture and Home Economics, State of Indiana, Purdue University and U.S. Department of Agri- culture Cooperating. H.A. Wadsworth, Director, West Lafayette, IN. Issued in furtherance of the Acts of May 8 and June 30, 1914. It is the policy of the Cooperative Extension Service of Purdue University that all persons shall have equal opportunity and access to our programs and facilities. .