Ventilation Basics Ventilation Basics ––How Do Your Pigs Feel?How Do Your Pigs Feel?

Amy Woods, DVMAmy Woods, DVMRensselaer Swine Services, P.C.Rensselaer Swine Services, P.C.

Purposes of VentilationPurposes of Ventilation

Control temperature and humidityControl temperature and humidityControl dust and gas levelsControl dust and gas levelsProvide adequate oxygenProvide adequate oxygenProvide optimal animal Provide optimal animal environment and worker comfortenvironment and worker comfort

* The effective environmental temperature (EET) is the actual ai* The effective environmental temperature (EET) is the actual air temperature r temperature adjusted for effects of draft, flooring type, building insulatioadjusted for effects of draft, flooring type, building insulation and supplemental n and supplemental

cooling. The EET is what pigs really feel.cooling. The EET is what pigs really feel.

Recommended Effective Environmental Temperature* For Pigs

50

60

70

80

90

100

10 25 40 55 70 85 100

115

130

145

160

175

190

205

220

235

250

Pig Weight (lbs.)

Effe

ctiv

e En

viro

nmen

tal

Tem

pera

ture

* (o F)

Temperature ControlTemperature Control

Factors Affecting Factors Affecting EffectiveEffectiveEnvironmental TemperatureEnvironmental Temperature

-13Poor-3Moderate-1High

Building insulation-18300 ft/min (3.4 mph)-1390 ft/min (1.0 mph)-730 ft/min (0.34 mph)

Draft

Change in EET (0F)Environmental Factor

-10Sprinkler-10Drip coolers-6Fogger/mister-5Cool cells

Cooling Systems-18Wet concrete-9Uncoated steel wire-9Dry concrete-7Plastic slats-7Plastic coated wire+5Lying mat+7Straw

Flooring Type

Change in EET (0F)Environmental Factor

Measuring TemperatureMeasuring Temperature

High/low thermometersHigh/low thermometersKnow how to read!Know how to read!Remember to reset!Remember to reset!

Current Temperature

(70oF)

Lowest Temperature

(52oF)

Highest Temperature

(82oF)

Also remember to rely on the behavior of the pigs as an indicator of their

comfort!!!

Temperature Probe PlacementTemperature Probe Placement

Temperature probesTemperature probesEnsure proper placementEnsure proper placement

Near pig levelNear pig levelNot in front of inlet or Not in front of inlet or heaterheaterNot in PVC tubeNot in PVC tube

Relative HumidityRelative Humidity

Goal: 50Goal: 50--70%70%Can be measured with a Can be measured with a thermohydrometerthermohydrometerOnly measure when minimum Only measure when minimum ventilation is runningventilation is runningMay have probes attached to controllersMay have probes attached to controllers

Probes do not last long in barn environments and are Probes do not last long in barn environments and are therefore inaccuratetherefore inaccurate

Relative Humidity EffectsRelative Humidity EffectsRH too highRH too high

Condensation apparent on pipes, etc. Condensation apparent on pipes, etc. Increased bacterial loadIncreased bacterial loadUnderUnder--ventilationventilation

RH too lowRH too lowExcess dust and gas levelsExcess dust and gas levelsIncreased LP costs due to overIncreased LP costs due to over--ventilationventilation

Ventilation CurveVentilation CurveAt lower temperatures, At lower temperatures, ventilation rate is based ventilation rate is based entirely on moisture entirely on moisture controlcontrol

This is when the minimum This is when the minimum ventilation fans only are ventilation fans only are runningrunning

After reaching the After reaching the setpointsetpoint, ventilation is , ventilation is based on heat removalbased on heat removal

Additional stages of fans Additional stages of fans turn onturn on

Types of VentilationTypes of VentilationMechanicalMechanical

Positive pressurePositive pressureForce air into barn through distribution tubeForce air into barn through distribution tube

Negative pressure/exhaustNegative pressure/exhaustTunnelTunnelSidewall or attic inletsSidewall or attic inlets

NaturalNaturalMay also utilize circulation May also utilize circulation fansfans

Ventilation Changes With The SeasonsVentilation Changes With The Seasons

Multiple ways to ventilate a single barnMultiple ways to ventilate a single barnTunnel in hot weatherTunnel in hot weatherNatural in mild weatherNatural in mild weatherBring air through inlets in cold weatherBring air through inlets in cold weather

Minimum ventilationMinimum ventilationVentilate based on moisture removalVentilate based on moisture removal

Maximum ventilationMaximum ventilationVentilate based on heat removalVentilate based on heat removal

cfmcfm RequirementsRequirements

30030050501212Sows & BoarsSows & Boars

12012035351010150# +150# +FinisherFinisher

75752424777575--150#150#GrowerGrower

35351515333030--75#75#NurseryNursery

25251010221212--30#30#PrenurseryPrenursery

50050080802020Sow & LitterSow & Litter

Hot Hot WeatherWeather

Mild Mild WeatherWeather

Cold Cold WeatherWeather

Cfm/hdCfm/hd

Approximate Fan CapacityApproximate Fan Capacity

20,00020,0004848””10,00010,0003636””6,0006,0002424””4,0004,0002020””3,0003,0001818””2,0002,0001212””

Approximate Approximate cfmcfm

Fan Fan DiameterDiameter

Fans Must Be Fully OperationalFans Must Be Fully Operational

Keep them cleanKeep them cleanA layer of dust on the fan and A layer of dust on the fan and louvers can decrease fan louvers can decrease fan efficiency by 20%efficiency by 20%

Keep motors and belts maintainedKeep motors and belts maintainedShield fans from prevailing windsShield fans from prevailing winds

Decreased efficiency if fans must work against Decreased efficiency if fans must work against wind forceswind forces

Inlets NeededInlets NeededPlace inlets no closer than 16 ft Place inlets no closer than 16 ft apart and no further than 24 ft apart and no further than 24 ft apartapartInlets should be no farther than Inlets should be no farther than 75 ft from the fan75 ft from the fan1 ft1 ft22 inlet for every ~800 inlet for every ~800 cfmcfmEnsure that airflow from inlets Ensure that airflow from inlets is not obstructed within the barnis not obstructed within the barnAirflow is dependant on inlet Airflow is dependant on inlet location, not fan locationlocation, not fan location

Inlet LocationsInlet LocationsSidewall inletsSidewall inlets

OK for buildings up to OK for buildings up to 3535--40 ft. wide40 ft. wide

Ceiling inletsCeiling inletsRequired for sufficient Required for sufficient air movement in wider air movement in wider barnsbarns

EffectiveEffective Inlet OpeningsInlet Openings

Remember that calculated inlet Remember that calculated inlet opening is often not equal to opening is often not equal to the effective inlet openingthe effective inlet opening

Wire screens = 80%Wire screens = 80%Dirty Dirty soffitssoffitsPlugged Plugged soffitssoffits

Other InletsOther Inlets

Ridge ventsRidge ventsDoorsDoorsHoles in curtainsHoles in curtainsSagging curtainsSagging curtainsCracks in wallsCracks in wallsNonNon--operational fansoperational fansPitsPits

Especially if no dividers between roomsEspecially if no dividers between rooms

Make Sure Natural Ventilation Is Make Sure Natural Ventilation Is Not ObstructedNot Obstructed

Objects near a barn will block air movement Objects near a barn will block air movement for a distance of 3for a distance of 3--4 times the obstacle4 times the obstacle’’s heights height

20 ft

80 ft

Inlet Air VelocityInlet Air Velocity

Goal: 800 Goal: 800 –– 1000 ft/min1000 ft/minIf to much inlet opening for If to much inlet opening for current fan capacity, velocity current fan capacity, velocity will decreasewill decrease

Air drops too soon and creates Air drops too soon and creates drafts on the pigsdrafts on the pigs

Want to have incoming air Want to have incoming air dump onto dunging areas in dump onto dunging areas in winter and sleeping areas in winter and sleeping areas in summersummer

Inadequate Inlet OpeningsInadequate Inlet Openings

Starved fansStarved fansBurn up fan motorsBurn up fan motors

Increased static pressureIncreased static pressurePressure difference between inside and outside the Pressure difference between inside and outside the barnbarnMeasured with a manometerMeasured with a manometer

Static PressureStatic Pressure

Goal: 0.04 Goal: 0.04 -- 0.1 in. water0.1 in. waterStatic pressure directly related to inlet air velocityStatic pressure directly related to inlet air velocity

100010000.070.079009000.060.068008000.050.057007000.040.046006000.030.03

Air Velocity Air Velocity (fpm)(fpm)

Static Pressure Static Pressure (in. H2O)(in. H2O)

Know Your ControllerKnow Your Controller

All are differentAll are differentRead the manualRead the manualVariable stagesVariable stagesTemperature curvesTemperature curvesUnderstand the settingsUnderstand the settings

BandwidthBandwidthDifferentialDifferentialOffsetOffset

BandwidthBandwidth

Bandwidth = Temperature difference (in Bandwidth = Temperature difference (in degrees) between minimum and maximum degrees) between minimum and maximum speed for variable speed fansspeed for variable speed fansShould always be at least 1Should always be at least 1oo

Set wider as pigs grow and Set wider as pigs grow and cfmcfm requirements requirements increaseincreaseSet higher in winter to allow barn time to Set higher in winter to allow barn time to respond to changes before activating next stagerespond to changes before activating next stage

Differential And OffsetDifferential And Offset

Used for single speed fans and heatersUsed for single speed fans and heatersDifferential = heater/fan run time (in degrees)Differential = heater/fan run time (in degrees)Offset = # degrees heater goes off under Offset = # degrees heater goes off under setpointsetpoint or # degrees for fan to come on over or # degrees for fan to come on over setpointsetpointOffset + differential = heater on or fan engages Offset + differential = heater on or fan engages next stagenext stageOffset = heater turns off or fan turns onOffset = heater turns off or fan turns on

Set point

Differential Heat on

Offset Heat off

Variable StagesVariable Stages

Temperature

cfm

Stage 2

Min.

Stage 1

Set PointBandwidth 1 Offset 2 Band-

width 2

Preparing Barns For WinterPreparing Barns For Winter

Cover fansCover fansMake sure to disconnect power supply first!Make sure to disconnect power supply first!

Unexpected warmer days may make the fan turn on and Unexpected warmer days may make the fan turn on and burn up the motor when covered.burn up the motor when covered.

Open baffles if changing from natural or Open baffles if changing from natural or tunnel ventilation to attic/sidewall inletstunnel ventilation to attic/sidewall inletsClean all inletsClean all inletsMake sure heaters are working Make sure heaters are working and pilot lights are litand pilot lights are lit

Any Questions Or Any Questions Or Comments?Comments?

THE ENDTHE END