residential weatherization and ventilation subcommittee seeking rtf direction on ventilation and iaq...

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Residential Weatherization and Ventilation Subcommittee

Seeking RTF Direction on Ventilation and IAQ Requirements

May 3, 2011

Subcommittee: Residential Weatherization and Ventilation

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Background

Subcommittee: Residential Weatherization and Ventilation Specifications

The Residential Weatherization and Ventilation Subcommittee has been working on revising the RTF’s Weatherization Specifications (for months)

The subcommittee is making progress… BUT

We’ve high-centered on ventilation requirements and could use some input/guidance from the RTF.

(Further Background: Current ventilation requirements have some obvious inconsistencies.)

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Subcommittee Requests RTF Guidance On:


1. Should ventilation/IAQ requirements be based on ASHRAE 62.2?A. If not, then what?

2. Is the “mitigation only” (aka “delta”) approach to ventilation/IAQ appropriate?

3. If yes to 1, are the proposed "simplifications" of 62.2 ok?

4. Is the application of ventilation/IAQ standards to only air-sealing and PTCS duct sealing measures appropriate, given the proposal to study ventilation/IAQ impacts of the other measures (insulation and windows)?

5. Should a maximum ventilation rate be specified?

Primary Issue

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Choosing a Ventilation Standard – Why not 62.2?

Issue 1. 62.2 or not?

Programs have been using standards other than 62.2 for years and don’t seem to be having major reported problems.

Too expensive to implement.

Too complicated.

Causes over-ventilation (wastes energy).

The industry, for the most part, has not yet adopted 62.2 – it may not be ready

There’s no proof 62.2 will cause better IAQ.Its allowance for exhaust-only ventilation could cause IAQ to be worse.

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Choosing a Ventilation Standard – Why 62.2?


ASHRAE Standard 62.2 is the nationally recognized indoor air quality standard for residences. 62.2 -2010 will be Required for US DOE Weatherization Assistance

Programs as of 2012. Referenced by EPA, CDC and HUD as the national guideline for IAQ. RESNET and BPI have plans to align with 62.2. Washington Department of Commerce moved away from 62-1989

toward 62.2-2004.

It was developed by the experts in the industry.

The old standards from ASHRAE are no longer valid, according to ASHRAE.

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Is 62.2 the solution to IAQ concerns?


The following is from the “Scope” section of the standard:

2.2 While acceptable IAQ 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 IAQ, 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;

e. When high-polluting events occur

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For WAP, Action, Testing, Education & Training


Required for US DOE Weatherization Assistance Programs as of 1/1/2012

ACTION/ALLOWABILITYVentilation 2010 (or most current) ASHRAE 62.2 is required be met to the fullest extent possible, when performing weatherization activity (must be implemented by January 1, 2012). Implementing ASHRAE 62.2 is not required where acceptable indoor air quality already exists as defined by ASHRAE 62.2. Existing fans and blower systems should be updated if not adequate

TESTING ASHRAE 62.2 evaluation, fan flow, and follow up testing are required to ensure compliance

CLIENT EDUCATIONProvide client with to information on function,. use, and maintenance of ventilation system and, components. Include disclaimer that ASHRAE, 62.2 does not account for. high polluting sources or guarantee indoor air quality.

TRAININGASHRAE 62.2 training required including proper sizing, evaluation of existing and new systems depressurization tightness limits, critical air zones etc.

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RTF Decision or Direction


1. Should the RTF use ASHRAE 62.2 as a model for developing its ventilation/IAQ requirements?

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Ventilate at a “Mitigation” level, or at the full level?

Issue 2. Mitigation only, or full compliance with 62.2 (or another standard)

ASHRAE 62.2 seems to lend itself to determining a mitigation level of ventilation for weatherization measures.

62.2-prescribed whole-house mechanical ventilation rates are dependent on:• Leakiness of the house (determined by blower door test)

• Higher blower door number = less whole-house ventilation• Presence and effectiveness of spot ventilation (bath and kitchen fans)

• Less spot ventilation = more whole-house ventilation

When performing house-tightening measures, a mitigation level of ventilation can be calculated

Mitigation Level = Post-weatherization Ventilation Rate – Pre-weatherization Ventilation Rate

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Issue 2. Mitigation only, or full compliance with 62.2 (or another standard)

Are weatherization programs responsible for:

A. Leaving the house with compliant ventilation (ventilate to full level prescribed by the standard), or

B. Leaving the house with ventilation no worse than in the condition it was found (Mitigate only)?

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Full Disclosure

Issue 3. Are the simplifications to 62.2 ok?

Full adherence to 62.2 is difficult and costly (whether calculating the “delta” or seeking “full compliance”).

The Big Deviations

62.2 requires testing bath and kitchen fans. Instead, proposal is to simplify by allowing contractor to determine operability of existing fans and whether they vent to outside:• Operable and exhaust outside = Full Credit (100cfm/50cfm)• Not operable or doesn’t exhaust outside = No Credit (0 cfm)

62.2 can give low CFM results. Instead, proposal is to only require installation of additional whole-house ventilation if the 62.2-prescribed post-weatherization continuous ventilation rate is 20 cfm or greater.

62.2, in section 6.4, states compliance with design requirements for venting of combustion appliances. Instead, proposal is to require worst-case CAZ testing and remediation for failed tests.

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Full Disclosure, continued


Smaller Deviations

Section 4.1.2 allows other designs by a licensed design professional. The proposed spec does not include this allowance.

Section 6.5.2 specifies a total leakage rate for duct systems with ducts outside conditioned space. Instead, the proposed specification will require either PTCS-certified duct systems, or prescriptive duct sealing on the ducts outside conditioned space.

Section 6.6.1 and 6.6.2 calls for ensuring adequate window-to-floor area in individual rooms in the house. The proposed spec does not include this requirement because a) it applies more to new construction and b) the proposed spec does not allow the window opening credit of section A3.2.

Section 6.7 requires filtering of certain supply air systems. The proposed spec does not include this requirement because, while the subcommittee may agree with the concept, the subcommittee does not see the value in adding it to the specifications.

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Are the proposed deviations/simplifications of 62.2 ok?

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Required When?

Issue 4. Plan for determining impact on “other” measures.

The Subcommittee’s proposal is to require mechanical ventilation standards to be met when performing the following measures (on any residential building type):

• Air-sealing (when performed “as a measure”)• PTCS Duct Sealing

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Not Required When?


The Subcommittee’s proposal is to NOT require mechanical ventilation standards to be met when performing the following weatherization measures (on any residential building type):

• Attic Insulation• Floor Insulation• Wall Insulation• Windows

BUT… The subcommittee acknowledges that reduction in infiltration rates are likely to occur with any of these measures.

The proposed insulation measure specifications have prescriptive air-sealing requirements that are identical to the “air-sealing as a measure” measure.

Why the inconsistency? ….

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Why this Inconsistency?


The subcommittee believes:1. Weatherization programs are not prepared to deal with the

costs and complexities of performing blower door tests to determine whether ventilation mitigation is required.

2. It’s unclear how much the prescriptive air-sealing performed for the individual insulation measures and window measures will impact infiltration rates, and therefore, ventilation rates.

The subcommittee proposes the region test #2 and prepare for #1 within the next three years.

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Research Plan


Objective:

Determine the ventilation impact (according to 62.2) caused by insulation and windows measures.

Method:

Perform pre- and post- blower door tests to determine the mitigation ventilation rate for 5% of the insulation and windows installations over the next 2 years.

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Is the application of ventilation/IAQ standards to only air-sealing and duct sealing measures appropriate, given the proposal to study ventilation/IAQ impacts of the other measures (insulation and windows)?

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Maximum Ventilation Rate

Issue 5. Specifying a maximum ventilation rate?

Ventilation standards (like 62.2) specify minimum ventilation rates.

The subcommittee is concerned about the energy impacts of “over-ventilating” above the standard.

The proposal (assuming 62.2) would be to disallow installation of whole-house ventilation systems resulting in rates higher than 125% of the 62.2-prescribed rate.

Note: this factor would be applied to the equivalent continuous rate for intermittently operating whole-house systems

If the maximum requirement is omitted, contractors could simplify whole-house fan selection by assuming “worst-case” (very tight house with no spot ventilation) in all cases.

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Issue 5. Specifying a maximum ventilation rate?

Should a maximum ventilation rate be specified?

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The Main Questions – Repeated:


1. Should ventilation/IAQ requirements be based on ASHRAE 62.2?A. If not, then what?

2. Is the “mitigation only” (aka “delta”) approach to ventilation/IAQ appropriate?

3. If yes to 1, are the proposed "simplifications" of 62.2 ok?

4. Is the application of ventilation/IAQ standards to only air-sealing and duct sealing measures appropriate, given the proposal to study ventilation/IAQ impacts of the other measures (insulation and windows)?

5. Should a maximum ventilation rate be specified?

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Extra Slide: Example Cases from a Utah Air-Sealing Program

Extra Slide

Examples: Pre and post whole-house ventilation cfm

Pre Vent Post Vent Difference Pre ACH Post ACH0 6 6 10.9 9.09 27 18 10.7 7.47 17 10 10.2 8.75 26 21 10.2 7.41 27 26 10.1 7.215 32 17 10.1 6.517 31 14 9.9 6.62 11 9 9.8 8.9

residential weatherization and ventilation subcommittee seeking rtf direction on ventilation and iaq...

Documents

ventilation subcommittee

ventilation standard

ventilation specifications

sitebuiltrequire ventilation

residential weatherization

maximum ventilation

ventilationiaq requirements

ashrae standard