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Musings of an Energy Nerd

Nuggets From the 2015 Westford Symposium

New perspectives on ventilating multifamily buildings, insulating old brick buildings, and achieving thermal comfort

Joe Lstiburek is one of the hosts of the annual Westford Symposium on Building Science. Along with his business partner and wife, architect Betsy Pettit, Lstiburek has hosted a three-day “summer camp” in Westford, Massachusetts for the last 19 years. The photo shows Lstiburek in his back yard, discussing his upcoming political campaign with a supporter. (Needless to say, the political button is actually a prank.)
Image Credit: Image #1: Martin Holladay

Building science experts, architects, engineers, and builders from across the U.S., Canada, and Europe gathered in early August in Westford, Massachusetts, for the 19th annual Westford Building Science Symposium, a conference sometimes known as “Summer Camp.”

Over three lively days filled with education, networking, and drinking, experts gave ten presentations on a variety of building science topics.

You read it here first

GBA readers who attended the conference had a sense of déjà vu at three of the presentations, since the talks covered topics that GBA has reported on in depth:

  • Marty Houston from Walsh Construction discussed the Orchards at Orenco development in Oregon, a project that has been the focus of a multi-part series of articles on GBA that began in November 2014.
  • Florian Antretter gave a presentation on hygric buffering research performed at the Fraunhofer Institute of Building Physics in Germany; my article reporting on that research was published in June 2015.
  • David Boyer and Tom Schneider gave a presentation on the air leakiness of OSB. According to conference host Joseph Lstiburek, my December 2014 article on the topic was the inspiration for Boyer and Schneider’s recent presentation. (For examples of the data shared by Boyer and Schneider at the recent symposium, see Images #2 and #3, below.)

Ventilating high-rise apartment buildings

Lorne Ricketts, a building science engineer at RDH Building Engineering in Vancouver, British Columbia, gave a presentation on research into ventilation systems in a high-rise multifamily building. (Ricketts and his co-author, John Straube, also reported their findings in a paper titled “Corridor Pressurization System Performance in Multi-Unit Residential Buildings.”)

For multifamily buildings, mechanical engineers often specify a type of supply ventilation system called a “corridor pressurization” (or “pressurized corridor”) system.

Ricketts explained, “A pressurized corridor ventilation…

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  1. Kevin Dickson, MSME | | #1

    We don't need no stinking compliance paths
    This is the first time ASHRAE 55 has been mentioned on GBA. For residential construction under about 4000 sq. ft., Holladay's Corollary can prevent any further mention of it:

    "If you build a Pretty Good envelope (or better), the only surface where radiant temperatures are a concern are windows — so if you live in Climate Zone 5 or anywhere colder, make them triple-glazed (or small)."

    Mind you, IAQ still needs more science and engineering thrown at it.

  2. GBA Editor
    Martin Holladay | | #2

    Response to Kevin Dickson
    Actually, ASHRAE 55 was mentioned 5 times on GBA before this article.

    I discussed ASHRAE 55 in my January 2015 article, What is Comfort?

    The other 4 references to ASHRAE 55 all occurred in posted comments:
    A comment by David White posted in November 2009.
    A comment by Dr. Dave posted in January 2011.
    A comment by Mark Siddall posted in April 2011.
    A comment by Robert Bean posted in April 2014.

  3. Expert Member
    Dana Dorsett | | #3

    Comfort, really? Some person will ALWAYS be uncomfortable.
    The mean radiant temp at which a person is comfortable depends on the age, gender and metabolic rate of the individual. As I often comment to mi esposa as she's cranking up the woodstove or tweaking the thermostat, "They SAY we're the same species, but I dunno... " :-)

    IIRC Joe Lstiburek commented a few years ago something along the lines of, "Five percent of all people will NEVER be comfortable!" There's some truth to that.

    There are Japanese HVAC designers promoting the concept that a static temperature is too monotonous, and makes people less comfortable and less productive (with some evidence to back that up.)

  4. GBA Editor
    Martin Holladay | | #4

    Sitting is the new smoking...
    Many GBA readers have probably been reading stories in the popular press about new research that shows that sitting causes health problems.

    The more hours a day that we sit, the unhealthier we are.

    "Sitting is the new smoking."

    So when I get up from my desk -- to close a window, open a window, or get a cup of tea because I'm chilly -- that's good.

  5. Dan Kolbert | | #5

    How about
    If i get up to smoke?

  6. GBA Editor
    Martin Holladay | | #6

    Response to Dan Kolbert
    It's got to be better than smoking at your desk.

  7. Robert Bean | | #7

    Responses to posted comments
    Response to Kevin Dickson, MSME

    Re: "...can prevent any further mention of it (Standard 55)"

    Understanding how humans respond physiologically and psychologically to the built environment gives roots to the philosophies of sustainability. The research that the Standards are based upon actually support the need for “Holladay's Corollary”. Mentioning it less only sustains the illiteracy (Westford slides 4 & 5) around why we build shelter to begin with…IMHO.

    Re: IAQ still needs more science and engineering

    I believe we are approaching a time of diminishing returns on IAQ science and engineering research (i.e. what we learn from here on in won't have a major influence on what we do in the future - recognizing there is a small potential I could be off-base on my evaluation)…in modern buildings, where high performance programs are embraced; chemical source control, particulate and gas filtration, moisture control and dedicated ventilation systems have resulted in air quality levels that now leave occupants complaining more about noise. This is based on post occupancy surveys of commercial office spaces (see Kim, deDear, Braeger et al). There is no database that I am aware of that can show this trend in modern housing also constructed to high performance standards but it seems to me the logic could be considered for homes. Anecdotally this is true for several of our residential forensic clients.

    Response to Dana Dorsett

    Re: "The mean radiant temp at which a person is comfortable depends on the age, gender and metabolic rate of the individual."

    Just to clarify for readers, in its most accurate form, MRT is relative to the geometric position of the occupant relative to a weighting of the surrounding surface temperatures. In a high performance building the MRT and dry bulb temperature are similar. It is the combination of MRT and dry bulb which define “operative temperature” - the value used in thermal comfort analysis (see Westford slide 53, X-axis). Gender nor age are identified as measurable/defined metrics in the ASHRAE Standard (see Westford slides 48 & 49).

    Side bar: Gender and thermal comfort has hit the news of late as posted in such high profile publications as The New Yorker ( ) but I’ll defer to Work Place Insight which includes ASHRAE’s rebuttal to recent research and articles addressing the gender topic (

    Age and physical disabilities are interesting studies unto themselves and I touched on this at Summer Camp and in greater detail at the 2015 Healthy Buildings America conference in Boulder, Co. (also available online). There is a separate ISO Standard addressing special groups (see Westford slide 101).

    Re: " 'Five percent of all people will NEVER be comfortable!' There's some truth to that."

    The Standard is based on general discomfort and local discomfort experienced by an occupant in the same space for more than 15 minutes. Local factors are not considered when met rates are above 1.3 and clothing values above 0.7. For general discussions if you look at the referenced 5% it applies approximately to most local discomfort tolerances. Meaning at low met rates and clothing, even if you get the air stratification, floor temperatures, radiant asymmetry and drafts under control, 5% will still complain about one or more local discomforts. Further even if you get the general and local factors right there will be 10% to 20% who will still complain - this is based on the 10% PMV/PPD index (see Westford slides 50 and 51). If you drill down deeper there are variances but I’ll leave that discussion for another day. These percentages are considered acceptable values. What thermal comfort researchers and dissatisfied occupants will argue is that for the 10% to 20% there is 100% failure. To put magnitude around the problem you have to dig into the survey data which shows much higher than 20% complaints for both residential and commercial buildings (see CBE reports, Honeywell surveys, Decision Analysts Home Comfort Survey, IFMA Survey, et al). Also note, comfort complaints are magnified with climate changes of consequence where buildings and systems are unable to respond to occupant needs which otherwise may have teetering on failure when outdoor environments are within norms. I didn't ask Michael Blasnik from NEST how many people bought their thermostats to solve a thermal comfort complaint but I would speculate it would be a non-trivial statistic. For additional interest utility provider Direct Energy, in Canada with over 6,000,000 customers, made a Zombie video about thermostat wars...going out on a limb (pun intended) thermal comfort was the stressor leading up to these actions (see

    Re: "...a static temperature is too monotonous, and makes people less comfortable and less productive (with some evidence to back that up.)"

    It is an interesting area of study – one that has been around a long time. As it relates specifically to standards, it is important to understand ASHRAE Standard 55 and ISO 7730 do not require a static monotonous environment. As pointed out at summer camp there is incredible flexibility in the three compliance paths. The simplest of these is the “Graphical Method” which allows between appx. 67F and 83F operative temperature and up to 0.012 moisture ratio with no minimum and air speeds up to 20 fpm again with no minimum. Additionally the operative temperature can swing up to 6F over a four hour period (not discussed at camp but is discussed in the Standard). Further flexibility can be obtained in the naturally ventilated space method and the most flexibility is offered in the analytical method where there are no maximums or minimums only combinations of factor that result in ranges of comfort. The operative word for all compliance paths is “range”, it is not and never has been a fixed value.

    Readers can see this in action when playing with the online CBE Thermal Comfort Tool (see Westford slides 56 – 59 and

    For those from Europe or China who also follow GBA, they should know they even have additional flexibility with their three class system.

    As Martin pointed out these compliance paths are not the easiest to navigate for some new user but they can be learned with training and practice much like any other skill - such as how to design and build a high performance building [;@)

    One of my key points at camp was put humans at the center of the design process and good buildings will follow. The flip side is put building design at the center and good environments will follow…equifinality works that way. The latter approach serves those who get the building sciences more so than the human sciences. If it leads to happier occupants who is to argue?

    Understanding how the building and human sciences are interconnected further enables design practitioners to make better building arguments for a populace that is interested in indoor environmental quality more so than energy; and it enables practitioners to make corollary arguments that good environments for people enabled by good building design fulfills in part the philosophies of sustainability.

    Thanks for the great article Martin ( and to Allison as well).

    Great seeing both of you at Summer Camp.

  8. GBA Editor
    Martin Holladay | | #8

    Response to Robert Bean
    Your writing is dense, and some of it is difficult to interpret. You wrote, "Gender nor age are identified as measurable/defined metrics in the ASHRAE Standard."

    If I understand the sentence correctly, I don't know why that lack is relevant to Dana's point. In fact, as we all know, age is usually easily defined and measured. And for about 90% to 95% of the human population, gender is also definable. So I'm not exactly sure why the fact that ASHRAE 55 does not identify these qualities as "measurable or defined metrics" is relevant.

    Perhaps you are saying something else -- that researchers have found that human response to mean radiant temperature is identical across all ages and all genders. But if that is what you are trying to say, I don't think you said it.

  9. Ronald Sauve | | #9

    Response to Robert Bean
    I respect you a great deal, but in your last entry here it seems you've spent a great deal of time with information that, while likely very accurate, is, as Martin said, a bit dense.
    Would it have a better effect, and better reach your audience if you put things more simply, concisely, and to the point?
    Again, I want to emphasize that I have a great deal of respect for your knowledge and expertise. Cheers!

  10. Robert Bean | | #10

    Reply to Dana
    Re: "The mean radiant temp at which a person is comfortable depends on the age, gender and metabolic rate of the individual."

    As far as ASHRAE 55 goes, the mean radiant temp at which a person is comfortable does not depend on age or gender.

  11. Kevin Dickson, MSME | | #11

    Trying to Keep Things as Simple as Possible
    ASHRAE 55 is probably useful for large office buildings, to help define human comfort.

    My point about the Holladay Corollary is that temperature control in a typical Pretty Good House is SO easy that residential builders don't need ASHRAE 55 to understand that they have succeeded.

  12. Robert Bean | | #12

    More responses to comments
    Reply to Kevin Dickson, MSME

    Re: “ASHRAE 55 is probably useful for large office buildings, to help define human comfort.”

    For the GBA readership, ASHRAE 62.2 - 2013, Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings states in section 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 55-2010, Thermal Environmental Conditions for Human Occupancy)."

    I can't speak on behalf of the Society but if asked I can pretty much guarantee the President would refer readers to official interpretations which state Standard 55 is applicable to residential buildings.

    Full disclosure: In addition to my position on SSPC 55 I am also a member of the new 2015-16 ASHRAE Presidential Residential Committee.

    Re: “My point about the Holladay Corollary is that temperature control in a typical Pretty Good House is SO easy that residential builders don't need ASHRAE 55 to understand that they have succeeded.”

    I understand and totally agree but when it comes to a Pretty Good House benchmark the same logic applies to any residential Standard not just ASHRAE 55.

    Rather than looking at the Standard from a less than positive position, I would suggest readers use it to help develop a deeper understanding of why the "Holladay Corollary" and the "Pretty Good House" make so much sense.

    Reply to Ronald Sauve

    Acknowledged, likewise and thank you.

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