Why ventilate? Dilute contaminants Control or aggravate humidity Comfort or lack of cooling Odors Provide oxygen

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2 Why ventilate? Dilute contaminants Control or aggravate humidity Comfort or lack of cooling Odors Provide oxygen

3 Outdoor Air (cfm/person) History of Minimum Ventilation Recommendations Reid 1844 Tredgold 1836 Billings 1895 Nightengale 1865 F l u g g e Yaglou 1936 smoking ASHRAE ASHRAE smoking A S H R A E

4 Equilibrium CO2 (ppm) SBS Rtsk Factor equilibrium co2 sbs data sbs curve fit Ventilation (cfm/person) 0 Sick Building Syndrome data from Jan Sundell Swedish Office Building Study

5 What Powers air flows? Fans Temperature Differences Wind

6 Ventilation (ACH) Ventilation - Albany, NY 8ach@50 4ach@50 2ach 2ach+hrv 4ach@50+exh Day of the Year

7 Does it all work? Dilution ventilation system: Central exhaust OA to return of AHU HRV/ERV Local exhaust: Bathrooms kitchen Combustion devices Clothes dryers

8 Does It Work? Local exhaust and dilution ventilation What speed? Fan flows Sound levels Pressure drop a cross the fan Watts Pressure map house? Indoors-outdoors for each mode? CAZ

9 More than a Fan Exhaust vent point sources to the outside Kitchen, bathroom, dryers (except condensing dryers), combustion devices, laundries Provide dilution ventilation Exhaust, supply, both Effective distribution Central air handlers? Baseboard or radiant heat? Air seal enclosure 1.25 in2 per 100 ft2 enclosure Multi-family issues

10 Getting a good ventilation system Design Spot exhaust Dilution ventilation and distribution Airtightness of enclosure and ductwork Filtration recirc/outdoor air Construction Kickoff meeting inspections Verification Duct leakage test and blower door test TAB

11 Design Ventilation Standards and Codes? IRC, IMC ft2window/100ft2 or 0.35 ach (not less than 15 cfm/person) mechanical Bath 1.5 ft2 window(1/2operable) or 50 cfm intermittent or 20 cfm continuous exhaust to outside Kitchens 100 cfm intermittent, 25cfm continuous Dryer must exhaust ASHRAE Residential Buildings 7.5 cfm/person+1cfm/100sq.ft. fan powered assumes additional 2cfm/100ft2 infiltration <4500 infiltration degree day exclusion Exhaust: Intermittent 100cfm kitchen, 50 cfm bath, or continuous 5 ach kitchen, 20 cfm bath (continuous exhaust fans can be used to meet the dilution requirement) Dryer must exhaust; range hood required if flow less than 5 ach Some noise and installation requirements

12 Design Local exhaust -Furnace -Dryer -Bathroom -Kitchen

13 Design Furnaces, boilers, solid fuel stoves, gas and oil hot water heaters all are exhaust vented to prevent combustion products from spreading throughout the house.

14 Design

15 Design

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17 Design

18 Design Recommendations for Bathroom Exhaust Grille within 6 inches of ceiling 20 cfm continuous 80 cfm boost controlled by motion sensor (light switch or timer switch ok)

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20 Design Fog never forms at 81 cfm

21 Design

22 Exhaust fan in basement, vented through rim joist fitting

23 Extraordinary rendition of ventilating air? do not torture air

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25 Worse installation

26 Is it working?

27 Is it the right amount?

28 CHECKING EXHAUST AIR VOLUMES Flowhood Must be capable of measuring air volumes below 50 cfm Anemometer Find the average air velocity in FPM Multiple by the free-vent area of grille in sq. ft. Gives volume in cubic feet per minute

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30 Duct Blaster as Exhaust Vent Flow Meter.

31 Duct Blaster as Exhaust Vent Flow Meter.

32 Duct Blaster as Exhaust Vent Flow Meter.

33 Traverse velocity measurements.

34 Traverse velocity measurements. Velocity less at edges No more than 6 inches o.c. at points of equal area. 8 duct dia. down stream 2 duct dia. up stream from elle or transition/ pdf/ih_sops/ih62470.pdf

35 More than a Fan Exhaust vent point sources to the outside Kitchen, bathroom, dryers (except condensing dryers), combustion devices, laundries Provide dilution ventilation Exhaust, supply, both Effective distribution Central air handlers? Baseboard or radiant heat? Air seal enclosure 1.25 in2 per 100 ft2 enclosure Multi-family issues

36 Distribution If ventilation was ducted to our mouths we d only need ¼ cfm per person (the amount of air a person breathes) But ventilation air must keep all the air in a home fit to breath Features that produce good distribution: Outdoor air ducted to many rooms House air exhausted from many rooms A central air handler that runs 10 minutes in each hour in combination with a ventilation system Be certain bedrooms get good ventilation

37 Distributed exhaust

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39 Compartmentalize Provide exhaust for baths and kitchens Stack effect in cold climates

40 Exhaust System Components Grilles in apartments or corridors Bathrooms Kitchens Mushroom fans on roofs

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45 flow pressure

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47 Multi-family ventilation issues

48 Each unit airsealed to 1.25 in2 per 100 ft2 enclosure No transfer to neighbors when system s on 4% transfer when one unit turned off 1-3% exhaust re-enters through trickle vents worst case

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52 Tightness Specifications 0.3 cfm50/ft2 enclosure Energystar High Rise Multi & ASHRAE 0.1 cfm50/ft2 to be certain about tobacco smoke transport

53 Outdoor air ducted to the return side of the air handler (air temperature at heat exchanger must be >60 degrees) Central exhaust removes air from kitchen and bathroom

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56 Outdoor air ducted to the return side of an air handler provides good distribution

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61 Transfer across closed doors

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63 Heat recovery ventilator ducts outdoor air to the return side of the air handler (air temperature at heat exchanger must be >60 degrees) and exhausts air from kitchen and bathroom.

64 Balanced ventilation systems provide good distribution (unless the exhaust and outdoor air are both ducted to a furnace distribution system)

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67 Integrated space heating, heat recovery ventilation and hot water heating

68 Effective HRV/ERV Layout Locate supplies where they won t blow on someone (e.g. bedroom closets, across ceiling) Locate exhausts in bathrooms, laundries and general kitchen area (strongest moisture and contaminant sources) Use dedicated ductwork for at least the supply or exhaust (don t use furnace or AC ducts for both supply and exhaust no matter how far apart you put them)

69 Sample Point 2 R - 2 R - 1 OA into return Up to 2nd floor returns Qbaseleaks Cbase Qmixed Cmixed QR3 Cup Qupleaks Cup-bas e Qshortcircuit Tracer injected here Sample Point 1 Csc Exhaus t Sample Point Cexh Exhaust flow grid measurement Low - 69 cfm High cfm 29 cfm of the 69 cfm exhaust shortcircuited from OA directly to exhaust

70 HRV/ERV system tips Put filters where exhaust and outdoor air ducts enter the HRV (MERV 8) Locate intake where it gets good air Best hard duct (flex only for short run on inlet and exhaust) Ok hard elbows-stretched flex Low noise, low wattage fans

71 Fan Power (wats) Fan Power is Important Energy Saved = Fan Use cfm 50 cfm Heating Degree Days

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74 h 4j 5 6 7k 7l m 10n p 13r m 16n k 19l h 22j f 25g

75 Ventilation rate 53 cfm 10 F 31 cfm 73 F 22 cfm 31 cfm 53 cfm NPL - 3

76 Ventilation rate 80 cfm gain 27 cfm 10 F 50 cfm 37 cfm 73 F 30 cfm NPL cfm 37 cfm

77 Ventilation rate 80 cfm 10 F 50 cfm 23 cfm 73 F NPL cfm 23 cfm 80 cfm

78 Ventilation rate 112 cfm gain 59 cfm 100 cfm 10 F 12 cfm 73 F NPL cfm 69 cfm 43 cfm

79 Ventilation rate 103 cfm gain 50 cfm 10 F 50 cfm 50 cfm 73 F 31 cfm 22 cfm 31 cfm 53 cfm NPL - 3