RELATIVE HUMIDITY AND POULTRY HOUSE VENTILATION William D. Weaver, Jr. Professor And Head Department OP Poultry Science Many times, when the condi tions of ambient air in the poultry house (or anywhere else for that matter) are discussed, they are described in terms of their temper ature and relative humidity. Temp erature is generally well under stood, as a thermometer measures dry bulb conditions and provides current ambient readings in degrees Fahrenheit. On the other hand, relative humidity, especially in combination with changing temperature, can be more difficult to comprehend. First let’s define some terms. “Relative” humidity, which is expressed as a percentage, indi cates the ratio of water vapor (moisture) suspended in the air to the quantity of water vapor in the air at saturation (at the same temp erature). Saturation, of course, rep resents 100 percent relative humidity. Understanding the relationship between temperature and relative humidity is also important. As the dry bulb temperature of air increases, its ability to hold mois ture also drastically increases. For example, the moisture holding capacity of air approximately dou bts for each 20 degree F increase in dry bulb temperature. 1 will return to the significance of this phenomenon when discuss ing ventilating poultry houses in a moment, but first let’&deflne a few more terms. On occasion, the term absolute humidity is used, which refers to the actual quantity of water vapor present in the air. This quantity is normally expressed as grains or pounds of vapor present per unit Animal Expo Nov. 8-9 LEBANON (Lebanon Co.) The 1995 Animal Housing Expo will be held Nov. 8-9 here at the Lebanon Fairgrounds. ‘The purpose of the expo is to help fanners in the Northeast leant m °re about animal housing con “ros,” said Dan McFarland, gen chair of the expo and Penn State Cooperative Extension Agent in York County. Approximately 1,400 people attended last year’s event to leant "tore about animal comfort, ani •Wl handling, building and remod e*®g animal housing facilities, S WI design and maintenance, ven t*«tion, fly control, financing, milking systems and more. , At this year’s Expo, presenta hons by nationally known and loc " ex Pert and producers, plus numerous demonstrations and dis- Puys will focus on a Vareity of top -ICI elated to animal housing and I®*- Wisconsin veterinarian Gor ~n Jones will discuss “A Vet’s Lommonsense Perspective of Gjw Comfort.” "Paying Attention to Swine Pro- (generally pound) of dry air. Wet bulb or saturation temperature, which has already been men tioned, is the temperature of the air when it is totally saturated with moisture or at 100 percent relative humidity. Another term, which is often confused with wet bulb or saturation temperature, is dew point temperature. The dew point is the temperature at which mois ture will begin to condense out of the air, and because of the energy required to convert vapor back to water, it is always a lower temper ature than at saturation. People that have a deeper interest in the rela tionship between moisture and temperature of air (known as psy chrometrics) should refer to a psy chometric chart which further illustrates these associations. Now back, to these relationships and how an understanding of them can aid in the ventilation of poultry houses. The biggest challenge during colder weather is that of removing moisture. With the knowledge that increasing the temperature of air increases its moisture holding capacity, producers can heat col der air and remove moisture. For example, a producer can bring in cold, damp (high relative humidi ty) air, heat it, and by doing so, reduce its relative humidity. Then the air with reduced rela tive humidity has the ability to “absorb” moisture from the litter and manure, and in conjunction with ei&aust fans, remove it from the poultry house. When realizing the moisture holding capacity of air essentially doubles with each 20 degree F increase in tempera ture, a producer can then bring air into a house at 30 degree F and 100 percent relative humidity, heat it until 70 degree F is reached and significantly increase its ability to hold moisture. In this case the rela tive humidity would be reduced from 100 percent to 25 percent. Air Housing duction Details” will be the focus of a veterinarian-producer panel. Tim Royer of Timber Tech Engi neering will talk'about “Avoiding Building Failures.” Attorney Gary Heim of Mette, Evans and Woodside will team up with Liz Brown, a tax consultant and preparer, to focus on the topic, “Your Business Will It Con tinue On Into The Future?” The question, “Do You Have Suffi cient Coverage?” will be addressed by Doug Wallick, Agway Insurance. Approximately 40 commercial exhibits will afford farmers an opportunity to see new products and concepts and to make contacts with people who can provide them with the products and services they need. Admission is free. Food is available and drawings will be made for door prizes. The event is sponsored by Penn State Cooperative Extension in conjunction with local agribu sinesses. For more information, contact your local cooperative extension office. at this relative humidity has a tre mendous ability to absorb and remove moisture from the poultry house. Another application 'of these relationships is used during war mer months in conjunction with ;evaporative cooling. First let’s explain that energy is required to convert water moisture to a vapor. As an example, 8747 BTUs are required to evaporate one gallon of water. For example, 8747 BTUs of cooling occurs when one gallon of water is converted from a liquid to a vapor. However, for this process to work, the air has to have die abil ity to absorb or hold additional water in the form of vapor. This brings us back to relative humidi ty . For if air temperature (dry bulb) is 95 degree F and the relative humidity is 45 percent (relative humidity in Pennsylvania is almost never above 50 percent when ambient temperature is 95 degree F or above), the air has the ability to hold additional moisture. Therefore, if the water vapor in the air is increased by SO percent (from 45 percent to 67.5 percent relative humidity), the air would be cooled by approximately 10 degree F. (Remember for each 20 degree F increase in temperature the moisture holding capacity of air is doubled.) This concept is used in most broiler, broiler breed er, and many turkey houses when using foggers and fogger pads, and evaporative cooling pads during the warmer months. Producers by in large know that warming outside air during the col der months allows it to hold more moisture, and that in the summer evapbrative cooling provides relief from the heat. However, the belief is that if producers have a clearer understanding of the concepts sup porting these practices, they will be better able to first operate and then fine tune their houses during both the hot and cold times of the year. MAILBOX MARKET FOR SALE Shop stove wood or coal, with regulator $l5O. Wanted-PTO hammermill. David Hoover, 888 Five pointville Rd, Stevens, PA 17578. Lane. Co. Model 791 modernmatic, 70 Case farm egg packer, no Sunday calls. Washing ton Co. 301-842-3543. New Idea com picker, nar row row $3800.24x24' But ler grain bin, no floor, no fans $l6OO. After 7 p.m. Bucks Co. 215-249-9151. Seed tye, stalk shredder, 2 row Nl. Manure spreader Nl 12A. Cattle feeder, Patz 60'. Rims tires off 320 JD. Harford Co. 410-692-5048. 25M1 Holdem electric fencer, wire roll, insulators, etc. $5O all. Metal tree trunk guards $.50 each. Hewn chestnut bam beams. Car roll Co. 410-374-6877. Small bucket a day stove with tank $45. Also estate heatrola coal stove $25. Gideon Stoltzfus, 202 Snake Hill Rd, Bird In Hand, PA 17505. Lane, Co. 9 month old Hereford bull, purebred, no papers, $5. Red Angus cow and calf heifer rebred for March 1996 $l3OO. York Co. 717-259-7626. Bake furnace for spray booth, 970,000 BTU excel lent shape, used little, 5 years old, sells new $llOOO, $3500 080. Mar ti n s b u rg, WV. 304-263-7554. Knitting RK9OO knitting machine, some extras, like new, table and some yam included. $5OO. Franklin Co. 717-532-7341. 1992 Cushman truckster dump body, 1 ton electric hoist, police bar lights, grain auger, Hollymatic pat tie mach, stacker slicer. Bucks Co. 215-257-7678. Male pygmy goat, very active $75. Two gas tanks with hand pumps 150 and 200 gal, $5O each. Chester Co. 610-657-9676. One seated mennonite car riage, 5 years old, good condition, on rubber. Lane. Co. 717-354-2772. Pony cart, rubber wheels, 32’, used only few times $650.1 cart with pole, nice condition $425. Lane. Co. 717-336-7273. Earth rite C fertilizer S-2-2-7 $205 a ton. Call in evenings. Lane. Co. 717-442-9013. IH TD6 62 series w/blade, PTO 6 cyl engine, home comfort wood/coal, 6 plate cook stove, white w/ water tank. Adams Co. 717-528-4914. Galloway 1 3/4 hp restored on truck, Webster mag, repainted, running shape $l2OO. Lebanon Co. 717-273-9554. Little Giant com drag, good condition $4OO 080. Howe 6xs' 50 ton capacity scale, with blue point $BOO 080. Lebanon Co. 717-272-5089. 2 ac+ farmette with 3 br log house, small, steam, some timber, fire wood, good land, Farmall Super C trac tor. Snyder Co. 539-8518. Peruvian Paso mare, 15h black, 8 yrs, smooth to ride, treat temperment, asking 3500. Willing to negotiate with knowledgable person. Branchville, NJ. 201-948-5383. Rye for cover crop combine run $3.75 bushel. Bulk dis count, leave message, will return call. Somerset Co. 908-359-5517. Oliver, 2 row com picker, #3 shed kept, field ready $2OO, call after 6 p.m. Lane. Co. 717-336-6949. Ml 279 cutditioner, good condition $lBOO. Dauphin Co. 717-665-5474. Used 24x40 double wide home, new windows, new kitchen, $l5OOO 080. 3 bedroom. Centre Co. 814-355-7489. Tennessee walkers, exc trail and field trail, several to choose from, 100% sound. Cold Springs Farm. After 5 p.m. Wapwallopen, PA. 717-379-3217. Horse beef or dairy farm 88 acres, 56 tillable, 4 bam complex, 5 bedroom home, stocked farm pond. Ontario Co. 716-394-8239. No 10 International 16 disc grain drill, very good condi tion, grain fertilizer, and grass seed boxes, ready to go. Berks Co. 610-678-3027. Troy-Bilt chipper, shredder, fits your horse tiller, PTO, A 1 shape, call for good price, after 4 p.m. Berks Co. 610-562-0528. Garage doors, steel insu lated, with all hardware included, excellent condi tion, 10x10' $3OO each. Schuylkill Co. 717-366-2404. Trac vac lawn vacuum tow model b&s, quantum engine, 48 gal, receptacle, used 1 season, perf oond, $450. Camden Co. 609-567-5583. Free-2 br Great Lakes mobile home with 11x26' addition and furniture. Also 1977 Road Runner factory t-tops, $l2OO. Montgomery Co. 610-631-1890. 600 series Ford forklift, 6000 lb capacity, steel wheels, excel condition $3500. Also step up trans mition $250. Lane. Co. 7170442-9489. German violin, full size with bow, exe cond, $3OO Liv ing room set, sofa, recliner, love seat, lamps, end tables, $3OO. Balto Co. 410-256-1168. 1980 DM Mack tri-axle, with dumpster roll off hoist, inside/outside rails, 300 engine, 7 speed transmis sion, price $l4OOO. Lacka wanna Co. 717-842-6464. Lancutar Farming, Saturday, October 7, INS-819 Mack equipment 300 engine, 5 speed transmis sion, rear tandem cutoffe. Neway tag axle, rolloff frame mside/outside, radia tors. Lacka Co. 717-842-6464. New Idea 5109 9ft haybine, good condition $3750. White 324 3 bottom 14" plow, $5OO. New points, colters. Rockingham Co. 540-879-9870. Team of Belgain mares, very gentle and safe, great for inexperienced, also ornate parade harnesses and horse equipment. Blair Co. 814-793-3410. Tools lathes, 15” cole Ches ter loaded, jewels power matic delta saws, 12" joint er, air shaper, planters, 20" band saw sanders, disk belt. Montgomery Co. 301-384-5376. Fence posts, 3"x7’ steel pipe $3 each. Lumber 2x3" and 2x4" $.50 each. Mont gomery Co. 215-234-8971. Clean sheep fleeces for hand spinning, other crafts. Many colors, white, grey, brown. Also wool yams and blankets. Dauphin Co. 717-362-4315. 1990 Ford extended cab, dually pickup, auto 460 asking $7500 080. After dark. Chenango Co. 607-639-2293. 1974 6 horse van, GMC CB radio, no C DL, swap 2-4 horse tractor, good shape, aluminum box, intercom, water tank, must see. $l3OOO 080. Delaware Co. 610-566-1332. Oliver 70 row crop SN 222868, good condition overall. 1938 $lO5O 080. Cumberland Co. 609-327-5165. Player piano 1924 story and clank birch, weed com pletely rebuilt refinished, and electrified, excellent condition, plays great $1250. Carbon Co. 610-377-2965. 1989 F 250 XLT Lariat, supercab, 4x4, 460 gas, 67000 $15500 080. 1974 GMC 6 horse van, gas No CDL, good shape $l3OOO 080. Possible swap. Dela ware Co. 610-566-1332. Farmall 504 tractor $3OOO. NH 271 baler $l5OO. NH 469 haybine $l2OO. IH MF grain drill $6OO. Somerset Co. 609-466-0553. JD #I4T baler, field ready $425. Zimmerman tetter, like new $llOO 080. Two old milk cans $l5 each. Dauphin Co. 717-545-7580. Wooden pallets and broken boards, some 2x4 hard wood, and some cutoffs for firewood Wanted 48x48 pallets. Berks Co. 610-670-9642 NH 770 harvester w 2m head $lB5O. JD 716 IH 110 Dion 3 beater wagons $B5O each. All neg Blair Co 814-944-0818. Buck wood stove, blower, $350. Harford Co. 410-676-2359. New Generac 3500 XL Genset, 3.5 KW, 29.2 amps, 6.5 hp, OHV gas engine, auto idle, wheel kit, 2 yr warranty $725. Lane. Co. 610-266-7093. N 1 323 picker $1950. Far mec bin wagon $750. Bril liant 10ft packer, Int fast hitch, post hole digger. Berks Co. 610-562-4464. 6HP lister generator, 104 amps, 12.5 kw, set of steel wheels, wanted for L 35 NH skidloader. Lane. Co 717-354-6310. 4 year old bay saddlebred carriage horse, traffic safe, sound, 16.9 h, Amos Hoov er, 682 Reidenbach Road, New Holland, PA 17557 Lane. Co. Int IVi hp engine, mode LA, pro 64 mod 70 win 30-06 with scope. Union Co 717-523-0352. 1934 Plymouth tractor, only 232 made. AC model B with elec start, and foot brakes. After 4 p.m. Warren Co. 908-475-3330. 12x55 holiday mobile home, about 1970 2 bed room, hot water heat, very good condition, ready to move $750. Call evenings. Lehigh Co. 610-285-2611. Bhp riding mower, Briggs and Stratton engine 30’ cut, with rear bagger, $2OO. Schuylkill Co. 717-345-8180. 157 acre dairy farm, 44 tie stall bam, 3 silo. Union Co. 717-524-2031. Ford 3 speed c/d standard trans, 1986, pedals, link age, bell housing, sno co tilt bed, utility trailer, 13* rub ber, winch on front. Cecil Co. 410-396-7680. Cub Loboy #154 wide front live PTO, turf tires, new with bully mower, kept inside $2950. MF rear weights for MF combines 5 of weights cultcase $l5. More. Dauphin Co. 717-652-5412. Belt driven 4000 watt generator, 120 or 240 volts, 16 amps, 32 amps. Lane. Co. 717-442-3218. Qehl 72FC chopper $BOO. Allied auger 741, $5OO. Wooden haywagon $3OO. Daffin Mill, 12“ roller mill $7OO. Lebanon Co. 717-867-1400. Mirafount hog waterer, 2 holes with lids, $225. 138 Pennsy Rd, Now Provi dence, PA 17560. Lane. Co. Acclumated horses and mules, 2 week trial. Henry Fisher, 331 Stauffer Rd, Lititz. PA 17543. Lane. Co. 1976 GMC 18' midwest dump body, 427 motor air brake $lO5OO. 410 John Deere backhoe $l2OOO. Wyoming Co. 717-833-4115. Little Giant com drag, Tyler PTO fertilizer spreader, NH 795 manure spreader, with top beater, hydraulic end gate. Lane. Co. 717-464-2398. One Hampshire service age boar, also hay and straw, large or small lots. York Co. 717-757-6062. 1969 Ford F 250 HD 4x4 for parts, good engine and run ning gear, price $6OO 080. Northampton Co. 610-266-6075. Auger cart, JD #6B works well, not rusted out, new paint $7OO. Berkeley Co. 304-274-3412. 14 hole modern ag hog feeders, finishing ex cond, $250 each. Lebanon Co. 717-866-7863. New Ford 1 ip, 3ph 2 bot tom plow, $525. New Ford 205 3ph, T disc harrow $650 or $llOO/both. Augusta Co. 540-886-3157. 357 New Holland grinder mixer, fair condition $lB5O. Lane. Co. 717-354-6829. Nice white silky chicks, var ious sizes, also grown roosters, Cadet 127 hydro with 48" mower. Berks Co 610-683-7902. John Deere A, 1947, good shape, good paint. After 6 p.m. Cumberland Co 717-776-7088. 1985 Apple II C computer, color monitor, imagewriter II color printer, extra rib bons, lots of software, man uals for everything, asking $4OO. Lebanon Co. 717-866-5215. Apples red and yellow deli cious stayman winsap, also juice apples. Hillside Orchards, 1765 Jug Rd, Dover, PA 17315. York Co. 717-292-4886. Two antique com shelters, good condition, both for $225. Also acoordian, 120 bass, good condition $175. Berks Co. 610-693-5624. 85 Jeep Cherokee, 4x4 2dr, newly rebuilt 2.81 engine, many new parts, new tires, $4200 After 5 Columbia Co. 717-387-0555. Sofa, floral design $55, Dauphin Co 717-944-9021.
Significant historical Pennsylvania newspapers