Considering Filtration. Austin Baker Ventilation Director Hog Slat, Inc

Transcription

1 Considering Filtration Austin Baker Ventilation Director Hog Slat, Inc

2 How will filtration help me? Will do: Provide producers the ability to protect animals from airborne pathogens. Won t do: Make up for poor biosecurity practices and protocols.

3 Questions to Consider How many animals are around me? How many animals will be around me in five years? How often do I break? What is my budget? Retrofit or new construction

4 Today s Areas of Focus Building Infiltration Points Major and Minor Maintenance Daily Checklist Pre-filter replacement Ventilation Design Positive vs Negative Selecting Fans Selecting Filters Back draft protection

5 Building Infiltration Points Major (biosecurity) Entry/Exit Rooms/Loadouts Pit Pump outs Minor (maintenance) Wall joints Windows Electrical, gas, water and feed line Exhaust Vents in shower and bathroom Filter or filter bank breach Pressure washer rooms

6 Major Infiltration Points Entry/ Exit Rooms/ Loadouts Double door system with + or - air flow All doors need a window Prefer stainless vacuum doors Buzzer and/or a red light need to be attached to the exterior door Consider painting floor for added psychological barrier Purge Fan connected to timer and switch activated by the closing of the exterior door (Cubic feet of room / cfm of in wc) + one minute.

7 Example 1. Room is 15 width x 15 length x 8 height = 1800 ft^ ft^3 / 4300 cfm =.42 min (25 sec) + 1 minute = 1 minute 25 second run time

8 Pit Pump outs Vacuum line lowest risk 6 pipe into low point of pit, agitation from inside the barn Traditional pump out Must pump during low risk days Try and seal any addition space around pump to minimize back draft. Negative systems are especially susceptible here

9 Minor Infiltration Points Air leaking between ceiling and sidewall need to caulk and check attic for adequate insulation as well as vapor barrier integrity

10 Source: Perry Hartman, Clarcor Minor Infiltration Points Filter Damage Need to replace damaged filters and check that there are adequate bait stations in the filter bank room.

11 Designing the Ventilation System Desired operating static pressure is 0.15 in wc Most exhaust fans are designed to operate in less pressure, so more fans are needed. This pressure is necessary to achieve a higher velocity through filters. Fans need to be able to provide maximum ventilation up to 0.3 in wc. This is the point at which pre-filters will need to be replaced.

12 Designing the Ventilation System Positive or Negative? Positive filtration uses less filters and minimizes the risk of back drafts but needs a way to distribute air. Requires a fully sealed attic or use of duct work Negative filtration is the most popular system design but also requires the most maintenance. Requires additional filters and filter boxes

13 Selecting Fans Airflow Ratio Fan output at.20 in wc / Fan output at.05 in wc Average is 0.75, choose fans from.80 and higher Must balance output and efficiency Could be operating at a 0.30 in wc

14 Example head gestation barn target 250 cfm/hd head 54 Fan requirement: 0.05 in wc = 28,100 cfm or 20 fans 0.15 in wc = 25,500 cfm or 22 fans 0.30 in wc = 22,600 cfm or 24 fans Use 24 fans 24 fans x 25,500 cfm = 278 cfm / hd

15 Selecting Filters Merv 14 minimum with Merv 8 prefilter Synthetic Pre-Filters and Main Filters Better resistance to humidity Higher airflow when compared to natural filters with the same Minimum Efficiency Reporting Value (MERV) Plastic frames Offer a better seal against frame and rigidity to the filter Cost Life of a pre-filter is approximately 6 months Life of a main filter is dependant on independent lab testing. Testing should start around year three.

16 Back Draft Protection Fan chute s length must be twice the diameter of the fan opening to ensure a good seal.

17 AP Backdraft Damper and Double L TopJet shutters Source: Automated Production Source: Double L Group

18 Z Wall Source: Perry Hartman, Clarcor Double shutter wall provides access to fans from the outside and traps air by constant negative pressure from smaller fan.

19 Maintenance Daily Checklist Filter banks for any rodent or filter damage/ bypass Back draft prevention i.e. broken shutter blades or torn missing socks If using inlet boxes inspect seal Inspect interior wall joints for leaks Condensation can be an indication Check pressure drop across filter bank(s) and record. (replace at.30 in wc)

20 Summary and Conclusion Sound design principles coupled with proven bio-security protocols and proper maintenance work.