EPA Indoor airPLUS and Radon Resistant Construction

0Today’s guest blogger is Tony Lisanti, PHIUS+ QA/QC manager. 

One of the prerequisite programs required for PHIUS+ Certification is the EPA’s Indoor airPLUS Program.  Born out of a need to minimize indoor air pollutants, the EPA dove-tailed this program with the ENERGY STAR Labeled Homes Program, which is also a prerequisite for the home or dwelling unit to earn both Indoor airPLUS and PHIUS+.  This serves to ensure that the dwelling unit is relatively tight, insulation is properly installed, the HVAC systems are properly sized, and bulk moisture throughout the building assembly is properly controlled.

Indoor airPLUS then takes indoor air quality to the next level. Integrating the Construction Specifications and Checklist requirements into the design, homes/dwelling units can then be verified to ensure greater precautions are taken for moisture control and dehumidification, air intakes are protected from birds and rodents, HVAC systems are kept clean, better filter media is used, and potential sources of moisture and contaminants are vented to the outdoors. Additionally, HVAC systems and ducts are prohibited in garages, pollutants from combustion equipment are minimized, and low VOC products are used.

One of the unique and important aspects of Indoor airPLUS is the requirement for radon-resistant construction measures in EPA Radon Zone 1. If you are not familiar with the Radon Zone map, it can be found here:  https://www.epa.gov/radon/epa-map-radon-zones.

Radon is a naturally occurring radioactive gas that can cause lung cancer. In fact, the EPA estimates that 21,000 deaths each year in the U.S. are attributable to radon exposure. The EPA has very good resources to read up on the health risks of radon. Their site can be found here: https://www.epa.gov/radon/health-risk-radon#head.

So why should PHIUS stakeholders be concerned with this? As mentioned above, PHIUS relies heavily on prerequisite programs such as ENERGY STAR and Indoor airPLUS. Since the airtightness standards for PHIUS Certified projects are up to 10 times more stringent than a typical code-built home, dilution of the indoor air cannot occur as readily. PHIUS ventilation requirements go well beyond those of systems found in typical Code built or even Energy Star Labeled homes. Good ventilation design, whether for code or for PHIUS starts with source control, i.e. minimizing the source of contaminants along with proper ventilation.

An example of a passive radon system.

An example of a passive radon system.

In high risk areas such as Radon Zone 1, EPA Indoor airPLUS requires installation of a passive radon system, at minimum. EPA also recommends utilizing active radon systems to further reduce radon concentrations in the home, although this is not yet an Indoor airPLUS requirement. The most modern radon standards are developed through an ANSI-accredited consensus process by the AARST Consortium (American Association of Radon Scientists and Technologists). EPA recommends following the ANSI/AARST CCAH Standard for 1-2 family dwellings and townhouses (max. total foundation area of 2500 sq. ft.) or the ANSI/AARST CC-1000 Standard for larger foundations, which often apply in multifamily buildings. However, the key components of a passive radon system for the purposes of Indoor airPLUS verification are succinctly outlined in Item 2.1 of their Construction Specifications.

ANSI/AARST will soon publish updated standards to provide guidance for the design and installation of two radon system options in new low-rise residential buildings. These systems, passive and powered, are designed to reduce elevated indoor radon levels by inducing a negative pressure in the soil below the building. The practice provides design and installation methods through soil depressurization systems that can be installed in in any geographic area.

Each of the two options consists of soil gas collection and a pipe distribution system to exhaust these gases. The first standard is for the design of passive radon reduction systems, sometimes referred to as a “radon rough-in” (ANSI/AARST RRNC). The second newly updated standard (anticipated in early 2020) includes details for a fan-powered radon reduction system, as well as radon testing (ANSI/AARST CCAH). Passive systems can result in reduced radon levels of up to 50%. These standards suggest that when radon test results for a building with a passive system are not acceptable, the system be converted to fan-powered operation. Typically, the action level is 4 pCi/L (Picocuries per liter). If the tested radon level exceeds 4pCI/L, then a fan is added to further depressurize the soil and positively vent the gas to the outside.

Recently, the EPA Indoor airPLUS team sent out this Technical Bulletin. The Technical Bulletin provides simple guidance on the installation of passive and active radon systems. Please pay particular attention to the drawings in the Bulletin, and note that the active system depicted has the fan located in a vented attic. This is outside the pressure/thermal boundary of the home. This has special significance with homes/buildings constructed to PHIUS Standards, because often, the attic space is WITHIN the pressure/thermal boundary of the home. Therefore, the fan cannot be located in the attic and must be outside the pressure/thermal boundary. The reason for this is, should there be a failure on the discharge or pressurized side of the fan, the building can actually be filled with radon gas.

Some other precautions that include a tight seal at the slab and vapor barrier to the vertical riser. Additionally, ensuring the riser is clearly labeled as “RADON” to minimize the chance that a plumbing waste line will be accidentally connected to it in the future is also important.

Tony Lisanti CEM, CPHC
PHIUS+ QA/QC Manager

With thanks to Nicholas Hurst from the EPA Indoor airPLUS Team

Policy Update: New York State—Two Steps forward, One Step back

isaac picIsaac Elnecave, a member of the PHIUS certification team, has written this update on the New York State stretch cove.

Over the last year, the state of New York has made significant progress towards making the PHIUS+ standard an integral part of its energy code. It points the way to the end goal of creating a cost-effective net-zero energy code.

Besides its statewide base code, the New York State Energy Research and Development Authority (NYSERDA) promulgates a “stretch” energy code (NYStretch-2020). The base energy code governs the energy requirements in buildings throughout the state. The requirements include such items as: the amount of insulation required in ceilings, walls and foundations, window performance, the level of air tightness, ventilation requirements, the efficacy of lighting and the efficiency of HVAC equipment. It is often described as the worst possible home that can legally be built.

A stretch energy code incorporates energy efficiency requirements that are more stringent than the base code (NYStretch-2020 is roughly 11% more energy efficient than the base code). While the base energy code is the default requirement across jurisdictions in the state, the stretch energy code must be affirmatively adopted by local municipalities (authorities having jurisdiction) that want to enforce it—at which point, it overrides the state code in that jurisdiction).

Besides providing energy savings beyond the base energy code, NYStretch-2020 was developed with the following goals in mind:

• Technically sound
• Thoroughly reviewed by stakeholders
• Written in code enforceable language
• Fully consistent with the 2018 IECC, ASHRAE 90.1-2016, and uniform codes

Moreover, NYSERDA strongly encourages, but does not require, that a jurisdiction adopting the NYStretch-2020 do so without making amendments.

In NYStretch-2020, there is a section for alternative compliance strategies (R-408), which specifically names passive house; a single-family home or low-rise multi-family certified under PHIUS+ would automatically meet code. The stretch code specifies that the specific space heat demand and (sensible only) cooling demand, as modeled and field-verified by a CPHC (Certified Passive House Consultant), must be less than or equal to 9 kBTU/ft2/year. A dwelling unit shall also be tested with a blower door and found to exhibit no more than 0.05 CFM50/ft² or 0.08 CFM75/ft² of air leakage. Ultimately, to provide a Certificate of Occupancy, a code official must submit a form that must indicate that the finished building achieves a CPHC verified specific space heat demand of less than or equal to 9 kBTU/ft2/year.

It is important to note that the PHIUS standard is even more energy efficient than the requirements in NYStretch-2020. Here is a link to NYStretch-2020: file:///C:/Users/phius/Downloads/NYStretch-Energy-Code-2020%20(7).pdf.

New York City
New York City provides an example of the importance of the stretch energy code. Local law 32 requires the city council to adopt the New York State Stretch code (allowing the inclusion of amendments). The language of the law is fairly clear:

Submit to the city council proposed amendments to this code to bring this code up to date with the most recent model stretch code published by the New York State Energy Research and Development Authority, provided that such model stretch code is more stringent than the New York State Energy Code in effect when such proposed amendments are submitted and provided further that such model stretch code was first published no more than three years before such proposed amendments are submitted;

As noted in the previous section, NYStretch-2020 is significantly more energy efficient than the base state code. Consequently, the city council is about to adopt NYStretch-2020 with one very important and unfortunate exception. R408, the section of NYStretch-2020 which allows for an alternate compliance path using PHIUS+, has been deleted. Here is a link to the proposed energy code  (Click on Int. No. 816 for the text of the code).

It is unclear as to why section R408 was deleted but it removes an important alternate compliance option for designers and builders. PHIUS+ incorporates both rigorous design standards with robust quality control protocols to ensure that the building is both energy efficient and well-constructed.

As the PHIUS standard is more energy efficient than the provisions of the NYStretch-2020, it also provides a target for future code improvements while giving designers and builders the time to develop expertise in building energy efficient dwellings; ultimately leading to the establishment of a net-zero energy code.

A mid-cycle tweak of PHIUS+ 2018

image-3

Space conditioning targets have been adjusted to reflect a statistical ‘Inclusive Fit’ rather than ‘Best Fit.’

PHIUS officially launched the PHIUS+ 2018 Passive Building Standard just over a year ago at the 13th Annual North American Passive House Conference in Boston. The passive building market seems to approve: not only have we gotten a lot of positive feedback from CPHCs and other design professionals, but PHIUS+ Certifications continue to increase. The most notable upgrades from the PHIUS+ 2015 standard add nuance to the space conditioning targets, adjusting them for building size and occupant density – passive building professionals do seem to appreciate this.  Another notable upgrade provides tiered source-energy targets and methods to hit those targets, depending on project goals.

Through the end of September 2019, PHIUS certification staff had the discretion to grant an exception for one of the four main space conditioning target criteria, as outlined in PHIUS+ 2018 Passive Building Standard-Setting Documentation, page 6. This allowance gave teams with projects already in planning some assurance that their efforts would not be wasted if their designs could not be revised to meet the new targets.  If a project was severely constrained on meeting a target, a “mulligan” could be granted based on majority vote from the certification staff. This also allowed flexibility in case the targets didn’t pan out in the real world even for clean-sheet designs.

Read the Full, Detailed Tech Corner Article

This “3 out of 4 ain’t bad” provision has now come to an end, and we have learned a lot from the many projects that have gone through the process. These case studies have allowed us to complete a mid-cycle evaluation of the standard. Determining optimum performance targets is an iterative process, and gathering feedback for future improvements is part of it. Thank you to all the teams that have certified to PHIUS+ 2018 helping us to dial in these improvements.

Moving forward, space conditioning targets have been adjusted to reflect a slightly different statistical fit from the original space conditioning target-setting process — an ‘Inclusive Fit’ rather than ‘Best Fit’ line. These updates will not disqualify any previously submitted projects in the PHIUS+ 2018 Certification process, as they are more inclusive than before. One sample graph of this is shown for the Peak Heating Load.

The Space Conditioning Criteria Calculator has been updated.

The Space Conditioning Criteria Calculator has been updated.

The resulting updated targets will be:

Cooling Demand = Original Target + 2.81 kBTU/ft2yr 

Heating Load = Original Target + 0.77 BTU/ft2hr

Cooling Load = Original Target + 0.45 BTU/ft2hr

The PHIUS+ 2018 Space Conditioning Criteria Calculator v2 has been updated to reflect the updates. Note the ‘v2’ at the end of the naming convention. 

Note

  • Projects with a contract date before October 1, 2019 may utilize only one path, (1) Use the updated calculator ‘v2’ or (2) Meet 3 of 4 space conditioning targets as described above.
  • Projects with a contract date after October 1, 2019 may only use the updated v2 calculator.

More details on this, as well as the graphs supporting the statistical analysis can be found in this Tech Corner Article

 

What’s new in WUFI Passive 3.2

Lisa White

Lisa White

By Lisa White, PHIUS Certification Manager

The PHIUS Certification Staff and PHIUS Technical Committee have been hard at work collaborating with the Fraunhofer Institute for Building Physics (IBP) to upgrade WUFI® Passive. And now, I’m happy to report that the Fraunhofer IBP has released WUFI Passive version 3.2!

This upgrade comes with many improvements, including full support of PHIUS+ 2018 modeling protocols and performance requirements. WUFI Passive is the only accepted modeling tool for PHIUS+ 2018 certification. Below is a summary of updates. Refer to the PHIUS+ Certification Guidebook v2.0, Section 6 for further details.

PHIUS+ 2018 Compliance Updates

PHIUS+ 2018 Criteria Calculator:

Space conditioning targets for a project can be calculated externally using PHIUS+ 2018 Space Conditioning Calculator or calculated within the software when PHIUS+ climate data, HDD65, CDD50, and marginal electricity price in $/kWh are input.

Source Energy Factors:
The source energy factors for electricity were updated, which dropped from 3.16 to 2.8 for the US, and to 1.96 for Canada.

Source Energy Targets:
The residential and non-residential source energy targets have been updated for PHIUS+ 2018. Source energy allowances for process loads in non-residential buildings can also be included in the reported target to verify compliance. See more on ‘Process Load Accounting’ below.

Air-Tightness Limit:
The air-tightness limit under PHIUS+ 2018 has been updated to 0.060 cfm50/ft2 for most buildings. For buildings 5+ stories of ‘Non-Combustible Materials’, there is now an adjusted target reported at 0.080 cfm50/ft2.

Renewable Energy Systems:
New options are included for modeling off-site renewable energy. The options are built in with the appropriate utilization factors according to PHIUS+ 2018 protocols.

DHW Calculation Methods:

PHIUS+ 2018 implements a new calculation method for hot water energy use of appliances, hot water distribution, and drain water heat recovery. See more under Technical Updates.

Technical Updates

Shading Calculation from Visualized Geometry:

WUFI Passive now harnesses capabilities of WUFIplus’ dynamic shading calculation to determine monthly shading factors based on the 3D visualized geometry. This includes shading from the building itself as well as any other surrounding structures that shade the building.

This calculation only takes a few seconds and greatly reduces the need for numerical shading inputs — speeding up the entire modeling process.

shading 3

Reveal Shading visualized:

Due to the new shading method described above, reveal or “in-set” shading for windows is now visualized in the 3D geometry when entered numerically.

Overhangs include ‘side spacing’:

Sometimes overhang depth and position are still in design and it’s easier if they aren’t included in the imported 3D geometry. They can still be input numerically. There is now the option to numerically enter an overhang that spans horizontally wider than the window width or is continuous across a façade.

shading 5

Removed shading landscape obstructions:

Due to the new dynamic shading method, horizontal/landscape obstruction entries have been removed. These may now be visualized in the 3D geometry instead.Accounting for these numerically with the new shading method is a work in progress and will be updated in the future.

Dishwashers, Clothes Washers, Clothes Dryers:

Annual energy consumption and hot water consumption for clothes washers, dishwashers, and dryers now follows ANSI/RESNET 301-2014 protocol, and the required inputs align directly with Energy Star ratings.

New Calculation Method for DHW Distribution:

New and improved methodology for designing and modeling DHW distribution has been implemented. The new method accounts for insulation on non-recirculating pipes, low flow fixtures, can more appropriately estimate hot water distribution losses from on-demand recirculation systems, and includes a tool to aid in the design of a DHW distribution network that will pass the on-site EPA WaterSense delivery test.

DHW 2

Drain Water Heat Recovery:

Drain water heat recovery can be an effective strategy in saving water heating energy by pre-heating incoming water with waste heat from shower drains, etc. A new mechanical system ‘device’ was added to support the calculation of drain water heat recovery when present

Process Load Accounting in Non-Residential Buildings:

A new tab under Internal Loads has been included to account for process loads. This allows for designating loads in the model as process loads. There is then the reporting option to include/remove them within the site & source energy results, and the option to increase the source energy allowance to include that load.

Process Loads 1

*Note: All process load allowances must be approved by PHIUS.

Modeling ‘Undefined’ or ‘White Box’ spaces:
A new non-residential occupancy mode was implemented to support modeling of Undefined spaces, i.e. in mixed-use buildings when a tenant is not yet determined. This simplifies one of PHIUS’ paths to certifying a mixed-use building.

User Friendliness

New Report: Site Energy Monthly Report

In addition to the existing results reports, a new report has been added to support comparison vs monthly utility bills. Previously in version 3.1.1, total annual Site and Source Energy use reports were available. This new report breaks the annual energy use into monthly estimates for both electricity and gas.

Site Energy 1

Updated Tool Tips:

The hover-over hints have been updated to align with PHIUS+ 2018 protocol. Activate them under Options>Usability>Tool Tip.

Case Name in footer of Reports:

In results reports, the project/case name was previously only shown on page 1. Now, you can activate the case name to be included in the footer of each page of the report. Activate under Options>Usability> Show project/case in footnote.

How to Update

Users of the professional version WUFI Passive 3.1 can download the update free of charge. Please log in to your account at the WUFI Web shop, there you can find the update link in the “My Orders” menu.

Free Tutorials: If you’re a beginner in WUFI Passive, utilize these free bite-size tutorials to guide you through your first model — http://www.phius.org/phius-certification-for-buildings-products/wufi-passive-tutorials

New capabilities in  v3.1:

New Heat Pump Device Types:

Two new devices have been added that follow PHIUS’ heat pump protocol. One for a Heat Pump Water Heater (with indoor compressor), and one that utilizes multiple heating COP ratings based on ambient conditions.

Data Recovery:

This is an auto-save feature that allows the user to define how often they want a file to auto-save, and how many ‘total’ files are saved (older versions from the same session drop off). Activate under Options>Usability.

Comment box:
Fraunhofer IBP implemented a comment box which allows users to add a unique comment to each input screen in the software. It can be used to remind yourself of a potential assumption that was made for an entry or use it as a log for model updates due to a change in design. If you’re submitting the project for PHIUS+ Certification, you can provide explanation for entries right in the software (though the feedback form is still the primary communication channel).

F1 for help files:
Before version 3.1, the WUFI Passive manual was a document external to WUFI Passive. The help files have been expanded and are integrated directly into the user interface! This feature can be accessed for any user input screen at any time using ‘F1’. There is an abundance of guidance here – take advantage of it, especially if you’re a first-time user.

Assign Data Button:
Along the top of the screen, an [Assign Data] button allows you to assign an entry (window type, shading entries, etc.) to multiple components at once. Huge time saver.

Export into XML File/Import from XML File:
User defined entries in your databases can be exported to an XML file and then can be shared with colleagues and (WUFI-friendly) friends. This includes all assemblies, materials, windows, HVAC devices, climates, etc. that have been created. Go to ‘Database>Export to XML’, and then select all items that you would like to be saved as an external XML file. If you receive an XML file, go to ‘Database > Import from XML’.

 

PHIUS+ 2018 Webinar Q&A

Screen Shot 2018-12-11 at 10.44.53 AM

PHIUS Senior Scientist Graham Wright and Certification Manager Lisa White answer questions that were submitted during and after the live PHIUS+ 2018 Webinar on November 8, 2018.

You can view a recording of the webinar at the PHIUS.org site.

*Note: Some questions have been edited for publication

Q: Has PHIUS started to look at overall GWP in the materials used to make these high performance buildings? To save the balance of the climate, reducing our emissions in the next 20 years is critical. Lots of XPS and spray foam make a low energy building but don’t do anything to help our climate goals.

A: The short answer is yes. We do have a GWP impact calculator for insulation. Its use is not required for project certification but we encourage it when we see large areas of XPS or SPF proposed. Our product certification program for construction systems has a requirement for a sustainability or health certification; there are several options recognized.

Q: Can you explain the exuberance concept?

A: We remain enthusiastic about the “tiny heating system” / “tiny heating bill” idea.

Q: Thanks for including Quebec Province! I believe in 2015+, all of North America was calculated according to a blanket value for cleanliness of the grid. Is 2018 adapted to different grids, and how do you deal with Quebec’s very cheap and clean hydroelectricity? Renewables are a tough sell here. Zero government incentives and at 7 cents/kWh, our energy costs would have to more than treble in order to make PV make financial sense.

A: In the standard-setting study itself we used the same factor all the time, but because the buildings were (almost) all electric, it canceled out. The PV generation is multiplied by the same factor as the usage, so source net zero is achieved with the same size PV array as for site net zero.

The philosophy is that CO2 emissions anywhere affect everyone everywhere. We all share one atmosphere, so by a principle of solidarity we should really use the world average source energy factor for electricity. That is, people with clean grids do not get to play “we’ve got ours” and use more energy. Even if your local grid is clean we want to drive additional action such as REC purchases that fund new clean energy projects. In certification we do allow the use of national averages, so we actually just request solidarity at the national level. Canada has a cleaner grid than the US overall, and thus Canadian projects will not have to take as many measures for net source energy reduction. The source energy factor for electricity in Canada is 1.96, whereas it is 2.8 for the US.

The electricity cost does affect some of the space conditioning criteria because higher energy prices justify more conservation measures and thus tighter targets. We calculate this with state-by-state averages, so Quebec projects will have less stringent targets than neighbors in Maine and Vermont.

 

Q: The word “townhouse” usually means a single-family building, but you seem to be using it differently.

A: The individual dwelling units are “single-family, attached”. That is, they share walls but not floor/ceiling. Speaking loosely, the whole row of attached units is the Townhouse, and the study building is 8 or 16 attached units.

Q: Is the mandatory minimum for window upgrades done because it wouldn’t be cost effective otherwise?

A: Yes. Window costs have come down but this still had to be forced in most cases. The starting points were still “in the money” though. There were a few times when the optimizer bought them on its own, but it took a long heating season and high energy price to motivate it. 

 

Q: Is this modeled EUI directly from WUFI Passive in the “Modeled vs. Measured” slide?

A: Yes, the WUFI Passive energy model used for certification.

Q: Do the new non-residential commissioning requirements apply to the common areas of residential buildings or only to all non-residential buildings?

A: TBD. Our current definition (for source energy target purposes) hinges on whether the spaces serve outside clients / customers or just the residents.

 

Q: Are you considering using the last 5 years of climate data vs ASHRAE to deal with global weirdness?

A: No, but we are working on future climate data for 2090 as an informational resource.

 

Q: Any comments on using low-iron glass (easily found in EU / just starting to appear in US)? Does the visible transmittance increase relative to ordinary US glass (which has a green tint to natural light)?

A: Alpen for a while had a low-iron glass option in their certified products, but they discontinued it.

 

Q: Instead of ignoring PV in competing with efficiency measures, why not look at PV with storage for the costs? This may not take care of seasonal differences, but it would take care of daily or weekly changes.

A: We may have have explored it if that was an option in BEopt, but it isn’t yet. Our current thinking is that what batteries do for you depends, in normal operation, on what the time-of-use rate structure looks like, and they are also good for you in outage situations. We are working on a calculation protocol for outages and waiting for utilities or other researchers to converge on time-of-use rate structure(s).

 

Q: Is there an ASHRAE 55 comfort analysis or PMV for PHIUS+?

A: The new window comfort calculator is based on relatively recent research on Predicted Percentage Dissatisfied specifically for draft at the ankle – it doesn’t just hark back to the PMV/PPD that was determined in 1970.

I (Graham) also wrote a paper for the 2016 conference looking at the radiant temperature effect of windows on comfort.

In certification we mostly take the same kind of simple view as in building code, e.g., “thou shalt maintain a dry bulb temperature set point of X and Y”. Sophisticated comfort analyses are more appropriate for workplace and nonresidential cases where clothing and metabolic profiles of occupants can be pinned down (as required by ASHRAE 55), and one might not have to worry so much about frail or sensitive occupants.

 

Comment: Adaptation is why I pursued CPHC in the first place!

Graham Wright: Thanks! Lisa presented on passive survivability at the Boston conference, and we will have more to say about this in the future.

Q: How does the new standard accommodate variable occupancy patterns/equipment usage in non-residential buildings?

A: With respect to the performance targets, as a first step, we will allow two different occupancies to be used to determine the annual demand targets vs. peak loads. Also, we can develop custom criteria for unusual situations (additional fee applies).

With respect to energy modeling protocol, it is already required to enter patterns for occupancy, ventilation and lighting, but this is mostly about getting the annual total energy right for source energy limit purposes.

 

Q: Please define HDD65, IGA, CDD50, TCD, IGCL and DDHR.

A: HDD65 = Heating degree-days, base 65 F;

IGA = Solar Irradiance, global, annual;

CDD50 = Cooling degree-days, base 50 F;

TCD = Temperature, cooling design day;

IGCL = Irradiance, global, cooling load design condition;

DDHR = Dehumidification design humidity ratio.

 

Q: If a project is considering registering under either 2015 or 2018, can we register under 2015 then change to 2018 (as circumstances change) without an additional registration fee?

A: Yes, you can always pursue a newer version of the standard. You are not able to pursue older versions if the contract date is later than the last day to submit under that older standard. In order to register for PHIUS+ 2015, the contract must be submitted before April 1, 2019.

 

Q: Are there updates to WUFI to accommodate the 2018+ standard? And when will it be available?

A: Yes, the next version of WUFI Passive will be released by the end of 2018. We will notify all of PHIUS’ mailing list.