ASHRAE for WAP WEATHERIZATION HEALTH AND SAFETY ASHRAE 62.2 FOR WAP

Transcription

1 WEATHERIZATION HEALTH AND SAFETY ASHRAE 62.2 for WAP 1 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

2 Learning Objectives By attending this session participants will: Understand how ASHRAE 62.2 will change the role of BTL/MVG. Learn the elements of ASHRAE Understand how to calculate ASHRAE 62.2 compliant fan CFM. Be exposed to different IAQ ventilation strategies. Learn an inexpensive method to measure exhaust fan CFM. Be exposed to a practical weatherization work flow sequence. 2 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

3 Beyond Fan CFM Requirements ASHRAE includes: Spot ventilation requirements as mentioned Attached garages must be adequately sealed from living space to prevent migration of contaminants Clothes driers must be vented to exterior All duct joints outside conditioned space must be sealed Sone rating requirements must be met Branch duct systems must have backdraft dampers Whole-home fan flow must be verified Continuous vs. intermittent fan specifications 3 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

4 How Much Air? Delivered How? What moves air through buildings? WIND DIRECTION Exhaust Fan Wind Buoyancy Stack effect - warm air rising Mechanical Fans 4 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

5 How has natural ventilation been calculated? N-factor variables: Geographic location Building height Building exposure The n-factor for the house illustrated at right would be different if it was one story taller, or less shielded. The map shown below is the LBL Climate Zone Map used to determine the geographic variable. 5 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

6 BTL/MVG/MVR Theory The amount of air leakage across any barrier is dependent on: Hole size Hole type The pressure differential Long/narrow vs. big/round Thick vs. thin surface Hairy vs. smooth bore Turbulent flow vs. linear flow vs. drag /friction 6 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

7 Why isn t the MVG our best tool? A single-point blower door test will see these holes as identical! Photos courtesy of The US Department of Energy The matched board ceiling above has many feet of linear cracks that expand and contract depending on relative humidity (RH). The missing flue plug creates a stable-sized round hole with little air flow drag. 7 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

8 Wx removes the randomness. Wind Effect Stack Effect Neutral pressure plane 8 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

9 A very important corollary! Based on single-story 1,500ft 2 house Ventilation Rate, CFM CFM 50 = 4000 CFM 50 = CFM CFM 50 = 2000 Desired ventilation = 75 CFM CFM 50 = Outdoor Temperature, degrees Chart F courtesy of Paul Francisco 9 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

10 What is the DOE requirement now? ASHRAE A Wisconsin pilot study conducted in 2004 found that 78% of weatherized units required additional mechanical ventilation under 62.2, up from 47% using the previous ASHRAE standard, Average installed cost, including controls: $525 ( prices) WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

11 ASHRAE Photos courtesy of The US Department of Energy 11 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

12 ASHRAE Table Table 4.1a: Minimum Ventilation Air Requirements, CFM, New Buildings 1 BEDROOMS Floor Area (ft 2 ) >7 < > ASHRAE , p 4 12 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

13 ASHRAE Formula New or Existing Buildings 2 : CFM fan = 0.01A floor + 7.5(Number bedroom + 1) + (alternative compliance supplement) - (Infiltration credit) A = conditioned floor area; the part of the building that is capable of being thermally conditioned for the comfort of occupants. (ASHRAE 62.2, p.3) Assumes two occupants in master bedroom and one each in the other bedrooms. Over this density, increase ventilation by 7.5 cfm/person. Whole building, intermittently operating ventilation may be used under some conditions for compliance. Ventilation air must come directly from the outdoors. Credit is allowed for envelope air leakage in some cases, based on ASHRAE 62.2 and Slide content from ASHRAE WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

14 ASHRAE Formula Breakdown CFM fan = 0.01A floor + 7.5(Number bedroom + 1) + (alternative compliance supplement) - (Infiltration credit) Break this down into 3 smaller steps: Use the base formula to determine the whole house continuous requirements = 0.01A * # occupants Calculate the local ventilation deficit (alternative compliance supplement) Calculate the infiltration credit 14 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

15 Calculating Required Fan CFM #1 Base formula: Whole Building Fan CFM = (7.5 * # bedrooms plus 1) + Area/100 Characteristics: 1,500 square feet 1 story 3 bedrooms (4 occupants) Norfolk, VA 15 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

16 Calculating Required Fan CFM #2 Base formula, step by step: Multiply the number of bedrooms + 1 or the number of people by 7.5 CFM per person: 4 people * 7.5 CFM/person = 30 CFM Calculate 1 CFM per 100 square feet of floor area: 1500 ft 2 /100 ft 2 per required CFM = 15 CFM Add them together: 30 CFM + 15 CFM = 45 CFM continuous 16 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

17 But what if they don t have adequate local ventilation? The alternative compliance supplement calculation lets you take the inadequate CFM delivery or total lack of required local ventilation fans into account. Kitchen requires 100 CFM on demand or 5 ACH continuous, based on kitchen volume. Bathroom requires 50 CFM on demand or 20 CFM continuous. Not required in ½ baths. Operable windows in those rooms reduce deficit by 20 CFM. Only one deficit reduction per room. Deficit cannot drop below zero. Sum all deficits and divide by 4. Add the result to the continuous whole building ventilation CFM requirement. 17 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

18 Alternative Compliance Supplement Calculation #1 Bathroom: 50 CFM required Existing fan = 20 CFM Operable window (reduce deficit by 20 CFM) = CFM req. 20 CFM existing - 20 CFM (window) = 10 CFM deficit Kitchen: 100 CFM required Existing fan = 70 CFM = 10 Operable window 100 CFM req. 70 CFM existing - 20 CFM (window) = 10 CFM deficit 18 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

19 Alternative Compliance Supplement Calculation #2 Net deficit in home: 10 CFM + 10 CFM = 20 CFM This is based on ondemand requirements. We will add capacity to the whole home continuous fan, so can reduce deficit. Divide deficit by 4 for additional continuous CFM requirement: Continuous CFM Req. from Base Formula = 45 CFM 20 CFM/4 = 5 CFM 45 CFM + 5 CFM = 50 CFM 19 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

20 Calculating the Infiltration Credit - Steps 1. Estimate infiltration rate at post-weatherization conditions (I CFM ). 2. Calculate default infiltration rate (I d ). 3. If I CFM is greater than the default rate, calculate infiltration credit (I cred ). Inputs needed: Weather factor from ASHRAE 136 S factor accounting for building height (table included) CFM 50 of the home, post-weatherization. Area of home, square feet of conditioned space. 20 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

21 Calculating the Infiltration Credit Step 1 1. Estimate infiltration rate at operating conditions (I CFM ). (I CFM ) can be estimated as: In this equation: I CFM = * w * S * Q 50 S is a factor accounting for the height of the building, determined from Table X-1 (included). Q 50 is the blower door test result in CFM50 (cubic feet per minute at 50 Pa). Since we are trying to determine the needs of the weatherized home, users must estimate what the CFM50 will be post-weatherization. w is the weather factor from ASHRAE Standard WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

22 S & W Charts # Stories S factor City W factor (from the table) * 1250 = 54 CFM Combine the two tables to simplify the calculation for your region * w * S * Q 50 Select city (left) and # stories (below) Multiply the S factor * * w to get a number you can input into the formula. Then all you need is the Q 50 for each home. If we get a Norfolk post-wx Richmon BD of 1250 Roanoke CFM 50 in our sample 1,500 ft 2, 1-story Norfolk d home, the estimated infiltration = * 0.84w * 1s * 1250 CFM 50, or City w Norfolk Richmond Roanoke WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

23 Calculating the Infiltration Credit Step 2 2. Calculate default infiltration rate (I d ) The default infiltration rate is the assumed leakiness, and takes the size of the home into account. I d = 0.02 * A floor A is the conditioned area of the home in square feet. For our sample home I d = 0.02 * 1500 = 30 This is lower than our estimated infiltration of 54 CFM, so we will continue to step 3 23 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

24 Calculating the Infiltration Credit Step 3 3. If I CFM is greater than the default rate (I d ), calculate infiltration credit (I cred ). This is where we account for the infiltration of the home that is above and beyond the default value. I cred = ½ (I CFM I d ) I cred = ½ (54 30) I cred = ½ (24) I cred = WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

25 Bringing it All Together CFM fan = (Base formula) + (alternative compliance supplement) - (Infiltration credit) We broke this down into 3 smaller steps and now have all the pieces to calculate our whole home continuous fan CFM requirement for our sample home in Norfolk: Use the base formula to determine the whole house continuous requirements = 0.01A * # occupants 1500ft 2 /100 + (7.5CFM * # occupants) = 45 Calculate the spot ventilation deficit = Net deficit/4 20 CFM/4 = 5 CFM deficit Calculate the infiltration credit = ½ (I CFM I d ) ½ (54 CFM 30 CFM) = 12 CFM credit CFM fan = (45 CFM) + (5 CFM) - (12 CFM) CFM fan = 38 CFM 25 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

26 Effect of Size What would change if we had the same home, but 2000 ft 2 instead of 1500? The base formula changes = 0.01A * # occupants Characteristics: 2000 square feet 1 story 3 bedrooms 1250 CFM ft 2 /100 + (7.5CFM * # occupants) = 50 The spot ventilation deficit is the same = Net deficit/4 20 CFM/4 = 5 CFM deficit The infiltration credit will change = ½ (I CFM I d ) Remember, I CFM = * w * S * Q 50, and I d = 0.02 * A FLOOR I CFM = * 0.84 * 1 * 1250 CFM 50 = 54 CFM I d = 0.02 * 2000 ft 2 = 40 I Credit = ½(54 40) = 7 CFM CFM fan = (50 CFM) + (5 CFM) (7 CFM) CFM fan = 48 CFM 26 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

27 Effect of Climate What would change if we had the same home, but in Portland, ME? The base formula is the same= 0.01A * # occupants Characteristics: 1,500 square feet 1 story 3 bedrooms Portland, ME (w = 0.91) 1250 CFM ft 2 /100 + (7.5CFM * # occupants) = 45 The spot ventilation deficit is the same = Net deficit/4 20 CFM/4 = 5 CFM deficit The infiltration credit will change = ½ (I CFM I d ) Remember, I CFM = * w * S * Q 50, and I d = 0.02 * A FLOOR I CFM = * 0.91 * 1 * 1250 CFM 50 = 58 CFM I d = 0.02 * 1500 ft 2 = 30 I Credit = ½(58 30) = 14 CFM CFM fan = (45 CFM) + (5 CFM) (14 CFM) CFM fan = 38 CFM 27 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

28 Effect of Deficit What would change if we had the original Norfolk home, but the kitchen fan delivered only 50 CFM, and the bathroom window didn t open? Bathroom: 50 CFM required Existing fan = 20 CFM No window credit = 30 CFM Kitchen: 100 CFM required Existing fan = 50 CFM Operable window = 30 CFM The base formula remains unchanged = 0.01A * # occupants 1500ft 2 /100 + (7.5CFM * # occupants) = 45 The local ventilation deficit increases = Net deficit/4 60 CFM/4 = 15 CFM deficit The infiltration credit doesn t change = ½ (I CFM I d ) ½ (54 CFM 30 CFM) = 12 CFM credit Net deficit = = 60 CFM CFM fan = (45 CFM) + (15 CFM) - (12 CFM) CFM fan = 48 CFM 28 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

29 Effect of Leakiness What would change if we got 2,000 CFM 50 instead of 1250 CFM 50 on the original Norfolk house? Characteristics: 1,500 square feet 1 story 3 bedrooms Norfolk, VA 2,000 CFM 50 The base formula remains unchanged = 0.01A * # occupants 1500ft 2 /100 + (7.5CFM * # occupants) = 45 The local ventilation deficit is the same = Net deficit/4 20 CFM/4 = 5 CFM deficit The infiltration credit will increase = ½ (I CFM I d ) Remember, I CFM = * w * S * Q 50 I CFM = * 0.84 * 1 * 2000 CFM 50 I CFM = * 0.84 * 1 * 2000 CFM 50 I CFM = 85 ½ (85 CFM 30 CFM) = 27.5 CFM infiltration credit CFM fan = (45 CFM) + (5 CFM) (27.5 CFM) CFM fan = 22.5 CFM 29 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

30 That s complicated! Three soon to be four? CFM calculation options: Appendix B of Ventilation Chapter in Workforce Guidelines for Home Energy Upgrades, DOE/NREL, 2011(details of the required math). ZipTest Pro 3 for the Texas Instruments TI-89 calculator (R.J. Karg Associates). ResVent 62.2 for the iphone, ipad, and ipod touch (R.J. Karg Associates). TECTITE from the Energy Conservatory, updated end of WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

31 Beyond Fan CFM Requirements Review Remember, ASHRAE also includes: Spot ventilation requirements as mentioned Attached garages must be adequately sealed from living space to prevent migration of contaminants Clothes driers must be vented to exterior All duct joints outside conditioned space must be sealed Sone rating requirements must be met Branch duct systems must have backdraft dampers Whole-home fan flow must be verified Continuous vs. intermittent fan specifications 31 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

32 Ventilation Options Once we ve determined required CFM, how do we get it? Exhaust only Multiple spot ventilation fans Balanced multiple intake - single fan, single exhaust system Supply only Into return side of HVAC system Direct through the wall fan Balanced Fan driven air in / air out Heat Recovery (HRV) Energy Recovery (ERV) 32 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

33 Exhaust Only Multiple Spot Ventilation Fans Source: 62.2 User s Manual 2006 ASHRAE 33 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

34 Exhaust Only Single System, Multiple Intakes Source: 62.2 User s Manual 2006 ASHRAE 34 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

35 Supply Only Supply only could also be a direct through the wall fan. Illustration of a supply only system with intake into the HVAC return ducting. Source: 62.2 User s Manual 2006 ASHRAE 35 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

36 Balanced Ventilation System Source: 62.2 User s Manual 2006 ASHRAE 36 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

37 HRV/ERV HRV ERV Photo Graphic courtesy courtesy of The of US Popular Department Mechanics of Energy 37 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

38 Other Possibilities Exhaust or supply systems with passive make-up air inlets or outlets. Exhaust or supply systems with active (fan powered, hopefully balanced) make-up air inlets or outlets. Supply or exhaust fans tied to HVAC systems Passive air inlets come in many shapes and sizes. The one shown here is from Panasonic. 38 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

39 Which system is right? 39 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

40 Cost-effectiveness Compare cost-effectiveness of exhaust only vs. HRV in a cold climate. Annualized cost = Installed cost/lifetime + annual operational costs + annual heating (or cooling) penalty. Fan Type Exhaust only, 20 CFM HRV, 20 CFM Installed Cost Lifetime (yrs) Operational cost/yr Heating penalty/yr 1 Total annualized cost $ $30 $110 $ 180 (Client pays $140) $1, $60 $55 $ 265 (Client pays $115) 1 Based on electric heat at $0.11/kWh in a 6,500 HDD climate. HRV assumed to reduce heat loss through fan by 50%. 40 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

41 Fan Flow Meter A fan flow meter connected to a manometer measures fan flow. This is necessary for deficit calculations, and to verify delivered CFM of newly installed fans. 41 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

42 Fan Controls Shown here: Tamarack Technologies, Inc and Airetrac fan control 42 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

43 Work Flow - Auditor 43 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

44 Audit Decisions CFM fan = (7.5 x BR+1) A + (5 (2.5 CFM CFM deficit) deficit) - (12 - (12 CFM CFM Infil Infil Credit Credit ) = ) = 3836 CFM CFM fan fan by replacing bath fan Characteristics: 1,500 square feet 1 story 3 bedrooms (4 occupants) Norfolk, VA 1,250 CFM50 20 CFM bath fan 70 CFM kitchen fan 44 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

45 Now lets replace the kitchen fan. CFM fan = (7.5 x BR+1) A - (9.5 CFM Infil Credit ) = 36 CFM fan Characteristics: 1,500 square feet 1 story 3 bedrooms (4 occupants) Norfolk, VA 1,250 CFM50 20 CFM bath fan 70 CFM kitchen fan 45 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

46 Work Flow - Installer Necessary ducting for existing fans must be properly installed to bring air into or out of the dwelling. Fan controls, like the one shown at right, must be installed to insure proper run times. 46 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

47 Work Flow - Inspector 47 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

48 Setting the control 48 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov

49 Summary The natural ventilation calculation we ve used for years is flawed when dealing with weatherized homes ASHRAE 62.2 is a performance standard fan flow must be measured. The math to compute the required fan flow can seem complicated, but is really a series of simple steps. Computer programs are available. The chosen ventilation method has to match local environmental conditions. A properly designed workflow process will not cause additional visits to the client home. 49 WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM October 2011 eere.energy.gov