Verifying & Measuring Ventilation Systems

Transcription

1 Verifying & Measuring Ventilation Systems Chip Henderson, AIA, CEM, LEED-Faculty 2012 RESNET Conference Austin, Texas

2 Indoor Air Quality Intent Ventilation System designed to meet ASHRAE

3 ASHRAE [Install] A mechanical exhaust system, supply system, or combination thereof shall be installed in each dwelling unit to provide whole building ventilation with outdoor air each hour at no less than the rate specified in Table 4.1 or equivalent equation based on floor area and number of bedrooms.

4 Indoor Air Quality Intent Ventilation System designed to meet ASHRAE Ventilation system does not utilize return side of HVAC system unless coupled with motorized damper and control system

5 Indoor Air Quality Intent Ventilation System designed to meet ASHRAE Ventilation system does not utilize return side of HVAC system unless coupled with motorized damper and control system System type, location, and design rate is documented*

6 Indoor Air Quality Intent Ventilation System designed to meet ASHRAE Ventilation system does not utilize return side of HVAC system unless coupled with motorized damper and control system System type, location, and design rate is documented If present, continuously-operating systems designed to operate during all occupied hours

7 Indoor Air Quality Intent Ventilation System designed to meet ASHRAE Ventilation system does not utilize return side of HVAC system unless coupled with motorized damper and control system System type, location, and design rate is documented If present, continuously-operating systems designed to operate during all occupied hours If present, intermittently-operating systems designed to operate at least once per day and at least 10% of every 24 hours

8 Indoor Air Quality Intent Raters are expected to use their experience and discretion to verify that each checklist item is installed per the inspection guidelines.

9 Indoor Air Quality Intent Raters are expected to use their experience and discretion to verify that each checklist item is installed per the inspection guidelines. Raters are expected to identify major defects that undermine the intent of the ENERGY STAR guidelines versus minor defects that the Rater may seem acceptable.

10 HVAC System Quality Installation Rater Checklist 5.1 Measured ventilation rate is within % of HVAC contractor design value. Rater shall measure ventilation and exhaust air flow using a flow hood, flow grid, anemometer, or substantially equivalent method in accordance with AABC, NEBB, or ASHRAE procedures.

11 HVAC System Quality Installation Rater Checklist 5.2 In warm-humid climates, (2009 IECC climate zones 1, 2 and parts of 3) measured NET exhaust flow < 7.5 CFM per 100 sq. ft. Net exhaust flow is the flow through the system minus the compensating outdoor (ventilation) airflow through any supply system that is interlocked to the exhaust system.

12 HVAC System Quality Installation Rater Checklist 5.3 In very cold climates, (IECC climate zones 7-8) measured NET supply flow < 7.5 CFM per 100 sq. ft. The inverse of net exhaust flow; the net outdoor (ventilation) airflow through any supply system should not exceed the exhaust system.

13 HVAC System Quality Installation Rater Checklist 7.1 Air Inlets & Ventilation Source Air inlets located 10 feet from contamination sources such as [plumbing] stack, [exhaust] vents, kitchen exhaust hood, or locations where vehicle exhaust may be present.

14 HVAC System Quality Installation Rater Checklist 7.1 Air Inlets & Ventilation Source Air inlets located 10 feet from contamination sources such as [plumbing] stack, [exhaust] vents, kitchen exhaust hood, or locations where vehicle exhaust may be present. Locate air inlets 3 feet from dryer exhausts and contamination sources existing through the roof.

15 HVAC System Quality Installation Rater Checklist 7.2 Air Inlets & Ventilation Source Locate air inlets 2 feet above grade or the roof deck in Climate Zones 1-3 or 4 feet in Climate Zones 4-8

16 HVAC System Quality Installation Rater Checklist 7.2 Air Inlets & Ventilation Source Locate air inlets 2 feet above grade or the roof deck in Climate Zones 1-3 or 4 feet in Climate Zones 4-8 Air inlet not obstructed by snow, plantings, or other material at time of inspection.

17 HVAC System Quality Installation Rater Checklist 7.3 Air Inlets & Ventilation Source Air inlets protected with rodent mesh or insect screen ½

18 HVAC System Quality Installation Rater Checklist 7.3 Air Inlets & Ventilation Source Air inlets protected with rodent mesh or insect screen ½ Air inlet not obstructed by snow, plantings, or other material at time of inspection.

19 HVAC System Quality Installation Rater Checklist 7.3 Air Inlets & Ventilation Source Air inlets protected with rodent mesh or insect screen ½ Air inlet not obstructed by snow, plantings, or other material at time of inspection. Ventilation air comes directly from outdoors and not from adjacent dwelling units, garages, unconditioned crawl spaces, or attics. *

20 HVAC System Quality Installation Rater Checklist 9. Sound Ratings for Fans (less than 400 CFM) Intermittent supply and exhaust fans rated at 3 sone or less by the manufacture

21 HVAC System Quality Installation Rater Checklist 9. Sound Ratings for Fans (less than 400 CFM) Intermittent supply and exhaust fans rated at 3 sone or less by the manufacture Continuous supply and exhaust fans rated at 1 sone or less by the manufacture

22 HVAC System Quality Installation Rater Checklist 9. Sound Ratings for Fans (less than 400 CFM) Intermittent supply and exhaust fans rated at 3 sone or less by the manufacture Continuous supply and exhaust fans rated at 1 sone or less by the manufacture HVAC and remote located fans are exempt

23 HVAC System Quality Installation Rater Checklist 11. Filtration MERV 6 filter or better installed in ducted mechanical systems. ASHRAE ducted mechanical systems are those that supply air to an occupied space through ductwork greater than 10 feet.

24 HVAC System Quality Installation Rater Checklist 11. Filtration MERV 6 filter or better installed in ducted mechanical systems. Filter is accessible by the owner ASHRAE ducted mechanical systems are those that supply air to an occupied space through ductwork greater than 10 feet.

25 HVAC System Quality Installation Rater Checklist 6. Controls Continuously-operating ventilation and exhaust fans include readily accessible override controls.

26 HVAC System Quality Installation Rater Checklist 6. Controls Continuously-operating ventilation and exhaust fans include readily accessible override controls. Intermittent mechanical exhaust systems (where provided) shall be designed to operate as needed by the occupant.

27 HVAC System Quality Installation Rater Checklist 6. Controls Continuously-operating ventilation and exhaust fans include readily accessible override controls. Intermittent mechanical exhaust systems (where provided) shall be designed to operate as needed by the occupant. Controls labeled, unless function is obvious (e.g. bathroom exhaust fan)

28 Supply Approach

29 Supply Approach

30 Photo by Dan Johnson

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33 Supply Approach

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35 Two Speed Exhaust Fan Low speed continuous Occupant controlled high speed Exhaust Approach Infiltration (?) make up air

36 Two Speed Exhaust Fan Low speed continuous Occupant controlled high speed Balanced Approach Known source of outside air

37 Teachable Moment Case Study

38 Moisture Management?

39 Moisture Management?

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41 ERV or HRV Balanced Approach

42 HVAC System Quality Installation Rater Checklist Duct Installation (aka Workmanship) Range hoods, bathroom exhaust fans, and clothes dryers shall be exhausted directly to the outdoors

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45 HVAC System Quality Installation Rater Checklist Duct Installation (aka Workmanship) Range hoods and bathroom exhaust fans will not deliver the rated airflow if the ductwork creates static pressure higher than the pressure used in the rating test.

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48 HVAC System Quality Installation Rater Checklist 5.1 Measured ventilation rate is within % of HVAC contractor design value. Rater shall measure ventilation and exhaust air flow using a flow hood, flow grid, anemometer, or substantially equivalent method in accordance with AABC, NEBB, or ASHRAE procedures.

49 Measuring Airflow Balometer Pros: Can be used to measure supply and exhaust Simple set up, easy to use Cons: Recirculating air flow patterns inside the hood can cause inconsistent readings

50 Measuring Airflow Powered Flow Hood Pros: Conditions air flow inside the hood for more accurate readings Can be used to measure supply and exhaust Cons: More time required to set up

51 Measuring Airflow Vane Anemometer Pros: Can be used to measure supply and exhaust Good for small systems or irregular openings Cons: The clear opening of the grille must be calculated

52 Measuring Airflow Exhaust Fan Flow Meter Pros: Cost effective option Simple and easy to use Cons: Maximum exhaust flow that can be measured is 124 CFM +/- 10% accuracy

53 Measuring Airflow Duct Blaster or Blower Door Pros: Can be used when direct contact with the ventilation system is not available Cons: Longer set up time

54 LET S REVIEW Raters are expected to use their experience and discretion to verify that each checklist item is installed per the inspection guidelines. Raters are expected to identify major defects that undermine the intent of the ENERGY STAR guidelines versus minor defects that the Rater may seem acceptable. Raters are expected to make adult decisions

55 Thank You! Chip Henderson, AIA, CEM, LEED-Faculty CONTECTS Consultants & Architects San Antonio, TX & New Orleans, LA