residential ventilation & iaq requirements for existing homes history, ashrae 62.2, and the...

Residential Ventilation & IAQ Requirements for Existing Homes

History, ASHRAE 62.2, and the RTF’s Role

Regional Technical ForumOctober 13th, 2009

History - BPA1981– Residential Weatherization Program allows

air tightening measures if home:• is site built• has ventilated crawlspace• Does not have wood stove, foam insulation

(formaldehyde), nor unvented combustion appliances

– IAQ brochures given to homeowners– Concerns: Radon, combustion byproducts,

formaldehyde

1989– “New Energy-Efficient Homes Program” RECORD

OF DECISION requires:• Exhaust fans in kitchens and baths• Whole House mechanical ventilation• Designated air supplies for combustion appliances• IAQ information given to homeowner• Building materials that meet HUD standards for

formaldehyde emissions• Attention to radon and mitigation as necessary

– Concerns: Radon and other indoor pollutants

Today– Site Built• Some air sealing measures

require whole house ventilation

• Other Wx measures don’t– Manufactured Homes• All measures require whole

house ventilation– New Homes all require whole

house ventilation

1980 1985 2010200520001990 1995

1984– “Expanded Residential Weatherization Program” RECORD

OF DECISION allows house tightening measures (storm windows, wall insulation, weatherstripping, door treatments, etc.) if:• Homeowner receives information on IAQ and how to reduce

pollutants• Radon monitoring is provided to homeowners• Homes with tested high radon levels receive subsidy for

mitigation– Concerns: Primarily Radon

1993– “Resource Programs” RECORD OF DECISION says:• Radon no longer an issue for either new home

efficiency programs nor existing home weatherization programs

• Otherwise, 1984 and 1989 ROD’s should be followed• Also, manufactured homes may be allowed, if they

follow the new homes ROD (1989).– They’re subject to more stringent requirements

because insulating manufactured homes is believed to decrease natural infiltration more than insulating site built homes

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Current RTF IAQ Requirements SummarySite Built Manufactured Homes

Insulation and Windows MeasuresVery Limited Ventilation

Requirements. (exhaust fan ducts cannot terminate in atti c or crawlspace)

Whole House Ventilation System Required and special requirements for combustion

appliances.

Air SealingWhole House Ventilation

System Required IF ACHn<0.45Whole House Ventilation

System Required.

PTCS Duct SealingNo Ventilation Requirements;

CO alarm required where combustion appliance inside.

No Ventilation Requirements; CO alarm required where

combustion appliance inside.Heat Pump Conversions No Requirements. No Requirements.

Multifamily New ConstructionWhole House Ventilation

System Required; Combustion Appliance Requirements.

N/A

Montana House

Whole House Ventilation System Required; CAZ test or CO alarm requred where atm

vented combustion appliance is inside heated space.

N/A

Energy Star Homes

Spot Ventilation Required (Whole house required in OR); CAZ test required where atm

vented combustion appliance is inside heated space.

Whole House Ventilation System Required.

New

Con

stru

ction

Existi

ng H

omes

Measure

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What Is 62.2? (From ASHRAE’s Website)ANSI/ASHRAE 62.2-2007 – Published standard. (Supersedes ANSI/ASHRAE 62.2-2004.)Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings1. PURPOSE: This standard defines the roles of and minimum requirements for mechanical and natural

ventilation systems and the building envelope intended to provide acceptable indoor air quality in low-rise residential buildings.

2. SCOPE: This standard applies to spaces intended for human occupancy within single-family houses and multifamily structures of three stories or fewer above grade, including manufactured and modular houses. This standard does not apply to transient housing such as hotels, motels, nursing homes, dormitories, or jails.2.1 This standard considers chemical, physical, and biological contaminants that can affect air quality. Thermal comfort requirements are not included in this standard (see ANSI/ASHRAE Standard 55-2004, Thermal Environmental Conditions for Human Occupancy).2.2 While acceptable indoor air quality is the goal of this standard, it will not necessarily be achieved even if all requirements are met:a) because of the diversity of sources and contaminants in indoor air and the range of susceptibility in the population; b) because of the many other factors that may affect occupant perception and acceptance of indoor air quality, such as air temperature, humidity, noise, lighting, and psychological stress; c) if the ambient air is unacceptable and this air is brought into the building without first being cleaned (cleaning of ambient outdoor air is not required by this standard.); d) if the system(s) are not operated and maintained as designed, or e) when high-polluting events occur.

2.3 This standard does not address unvented combustion space heaters.

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ASHRAE 62.2 – Basic Components• Whole Building Mechanical Ventilation System

– Required CFM = 0.01 x Floor Area + 7.5 x [(Number of Bedrooms)+1]Note: adjustments are made for high occupant density and intermittent operation

• Local Mechanical Exhaust– Kitchens = 100 cfm– Bathrooms = 50 cfm(Note: Continuous operation also allowed at different rates)

• Other Requirements– Prescriptively seal house between attic, crawl, garage– Provide ventilation system instructions to homeowner– Combustion appliances

• receive adequate combustion air • where atmospherically vented appliances are inside occupiable space, additional requirements if two

largest exhaust fans have flow rate > 15cfm/100 square feet of floor area. – Total duct leakage must be < 6% of total fan flow at 25 Pa if ducts are located in the garage.

• PROPOSED SPEC: Required anywhere ducts are located outside the pressure boundary.– Rooms must have ventilation openings (i.e. openable window area) of 4% of floor area or

greater. (exceptions)– Filtration requirements for systems that use ducts– PROPOSED SPEC: CO alarm required (Out for public comment until Oct 26 th)

• Equipment Requirements– Tested and rated for flow and sound according to HVI– Sound ratings: Continuous fans < 1 sone; Intermitent Fans < 3 sones– Use tested airflow; or use airflow rating at 0.25 in H20 with proper duct design

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ASHRAE 62.2 – Existing Home Exceptions

• Inadequate Existing Bath/Kitchen Fans– An increase in whole-house ventilation rates can be used to

overcome a deficiency in existing bath/kitchen fan flow rates.

• Infiltration Credit– Existing homes with an effective infiltration rate greater than

2cfm/100ft2 may use a portion of this “excess” infiltration to reduce the required whole house ventilation rate. Effective Infiltration is estimated based on:• House tightness (blower door test)• Climate• Building height

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Leakage Area (ASTM 779, w/caveats 4 and 5) 0.80 sq. ft.Normalized Leakage (ASHRAE Std 119) 0.44Effective AirChange Rate from Infiltration (ASHRAE Std 136) 0.38 ACH

Inputs Effective Infiltration Flow Rate 113 cfmHouse Floor Area 2,000 sq.ft. ASHRAE 62.2 Default Infiltration Credit 40 cfmHouse Volume 18,000 cubic feet Excess Infiltration 73 cfmVertical Distance from lowest grade level to highest ceiling 11 feet Section 4.1 Whole House Ventilation Rate 50 cfmNumber of Bedrooms 3 bedrooms Section 4.1.1 Different Occupant Density 0 cfmNumber of Bathrooms 2 bathrooms Section 4.1.3 Infiltration Credit -36 cfmNumber of Occupants 3 people Section C3.3 Required Additional Airflow 25 cfmBlower Door Test Performed? 1 Mechanical Ventilation Air Requirement 39 cfmBlower Door Tested CFM at 50Pa depressurization 2100 CFM50 Fractional On-Time 1.00City Cycle Time 24Whole House Fan on-time per cycle 24 hours Fractional On-Time rounded down 1.00Whole House Fan off-time per cycle 0 hours Ventilation Effectiveness 1.00Kitchen Exhaust Fan's Measured Airflow Rate 50 cfm Initial Room Airflow Deficit: Kitchen 50 cfmBathroom 1: Exhaust Fan's Measured Airflow Rate 25 cfm Initial Room Airflow Deficit: Bathroom 1 25 cfmBathroom 2: Exhaust Fan's Measured Airflow Rate 25 cfm Initial Room Airflow Deficit: Bathroom 2 25 cfm

2525252525

ASHRAE 62.2 Whole House Ventilation Requirements Calculator

Results Intermediate Outputs

Required Whole-House Fan Measured Flow Rate => 39 cfm

Purpose: This calculator is intended to determine the required whole house ventilation fan flow rate for existing homes, according to ASHRAE Standard 62.2.

Instructions: A. Enter the necessary data into the green "Inputs" section of the calculator (Cells C15 through C33)B. Fix any inputs causing errors, as necessary. (cells B5:H8)C. The resulting required whole house flow rate, in cfm, is given in cell C11:12.

OR - Astoria

Yes

7

ASHRAE 62.2 – Example Home #18

Note: Current RTF standard for manufactured homes is always required and independent of ACHn.

0

50

100

150

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Who

le H

ouse

Ven

tila

tion

Rat

e (c

fm)

"Natural Air Exchange Rate" (ACHn = ACH50/20)

ASHRAE 62.2 Continuous Whole-House Ventilation Requirement

(2 bed/1 bath, 1-story, 1100 ft2, Portland)

0cfm/0cfm

25cfm/50cfm

50cfm/100cfm

_

Current RTF Standard

Measured Bath/Kitchen Fan

Flow Rate


0

50

100

150

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Who

le H

ouse

Ven

tila

tion

Rat

e (c

fm)




0cfm/0cfm

25cfm/50cfm

50cfm/100cfm

_



Flow Rate


Which Efficiency Measures Should Apply?The subcommittee tentatively has agreed that everything except heat pumps should receive

some kind of IAQ attention.

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Mechanical Ventilation Required?

Attention to CO?

Air Sealing Yes Directly reduces infiltration in the building shell If ACHn < 0.45 No

Duct Sealing Yes Directly reduces infiltration of the HVAC system No Yes

Wall Insulation Very LikelyInsert-tube method is required. Dense-pack is

allowed (and encouraged).No

(Yes for MH)No

Window Replacement Very Likely Caulking, etc. to reduce infiltration No(Yes for MH)

No

Attic Insulation Likely Specifications require prescriptive air-sealing No(Yes for MH)

No

Floor Insulation Likely Specifications require prescriptive air-sealing No(Yes for MH)

No

Heat Pump Conversion PossibleAddition of ducts a) influences (likely to increase) infiltration rate and b) could cause backdrafting.

No No

Heat Pump Upgrade No Unit was going to be replaced anyway No No

Current RTF Requirements

Comments

Negative effect on

IAQ?Measure

What do Others Require?

• ASHRAE 62.2– Wisconsin– California– Others?

• Older Versions of ASHRAE (62-2001)• At least 0.35 ACH and 15 CFM per person

– Low Income Weatherization Programs– Others?

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What might it look like to implement ASHRAE 62.2 for Wx Programs?

• Ventilation Rate Calculator• Increased Costs

– Blower Door Test– Exhaust Fan Flow Tests– Whole House Fan & Controller Installation– CO Alarm (?)– Training (LOTS of training)

• Oversight/Verification• Incorporate ASHRAE 62.2 updates

????

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Leakage Area (ASTM 779, w/caveats 4 and 5) 0.80 sq. ft.Normalized Leakage (ASHRAE Std 119) 0.44Effective AirChange Rate from Infiltration (ASHRAE Std 136) 0.38 ACH

Inputs Effective Infiltration Flow Rate 113 cfmHouse Floor Area 2,000 sq.ft. ASHRAE 62.2 Default Infiltration Credit 40 cfmHouse Volume 18,000 cubic feet Excess Infiltration 73 cfmVertical Distance from lowest grade level to highest ceiling 11 feet Section 4.1 Whole House Ventilation Rate 50 cfmNumber of Bedrooms 3 bedrooms Section 4.1.1 Different Occupant Density 0 cfmNumber of Bathrooms 2 bathrooms Section 4.1.3 Infiltration Credit -36 cfmNumber of Occupants 3 people Section C3.3 Required Additional Airflow 25 cfmBlower Door Test Performed? 1 Mechanical Ventilation Air Requirement 39 cfmBlower Door Tested CFM at 50Pa depressurization 2100 CFM50 Fractional On-Time 1.00City Cycle Time 24Whole House Fan on-time per cycle 24 hours Fractional On-Time rounded down 1.00Whole House Fan off-time per cycle 0 hours Ventilation Effectiveness 1.00Kitchen Exhaust Fan's Measured Airflow Rate 50 cfm Initial Room Airflow Deficit: Kitchen 50 cfmBathroom 1: Exhaust Fan's Measured Airflow Rate 25 cfm Initial Room Airflow Deficit: Bathroom 1 25 cfmBathroom 2: Exhaust Fan's Measured Airflow Rate 25 cfm Initial Room Airflow Deficit: Bathroom 2 25 cfm

2525252525

ASHRAE 62.2 Whole House Ventilation Requirements Calculator

Results Intermediate Outputs

Required Whole-House Fan Measured Flow Rate => 39 cfm

Purpose: This calculator is intended to determine the required whole house ventilation fan flow rate for existing homes, according to ASHRAE Standard 62.2.

Instructions: A. Enter the necessary data into the green "Inputs" section of the calculator (Cells C15 through C33)B. Fix any inputs causing errors, as necessary. (cells B5:H8)C. The resulting required whole house flow rate, in cfm, is given in cell C11:12.

OR - Astoria

Yes

Discussion: RTF’s Role and Issues• Does the RTF have adequate expertise in IAQ? If not, then who?• If we attempt to follow 62.2:

– Can we get “close enough” on some requirements and are there some we can ignore?– For which measures should 62.2 be required? – Should there be differences for single family, multifamily, or manufactured homes?

• It’s one thing to have a spec, but how should IAQ requirements be verified? IAQ doesn’t save energy; will it receive attention?

• Will the added cost/burden put a stop to Wx programs?• What about new construction?

Potential Options: 1. Have subcommittee incorporate 62.2 into measure specifications, also set up

quality assurance plan & requirements;2. Keep specs as they are;3. Pass this IAQ job on to someone else (BPA?, codes?);4. Suggest, but don’t require: Rely on letting the (informed) homeowner make

the decision about what IAQ strategies to employ.

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residential ventilation & iaq requirements for existing homes history, ashrae 62.2, and the...

Documents

air tightening measures

acceptable indoor air

ansiashrae standard

published standard

house ventilationnew

nursing homes

insulating manufactured

stringent requirements