2014 BCBC Envelope Compliance - ASHRAE 90.1 and NECB

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This presentation includes and overview of ASHRAE 90.1 2010 and NECB 2011 building envelope prescriptive requirements and trade off method, how to account for thermal bridging and the real R value of envelope assemblies.

Presented at the 2014 AIBC Shifting Perspectives Conference.

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  • Shifting perspectives logo
  • I am Sophie…
    A little bit of house keep to start:
    AIBC Credit sign in sheet
    3hr session, 2 breaks
    Washroom
    Cellphone

    Now with the program… read the slide
  • So why are we talking about energy standards today.
    Because they are part of the Code and as professionals we have to make sure they are being met
    Reference in the Code is found under part 10
    And It is in schedule B that you are signing for it
    The snap shot of the schedule here shows the envelope requirement,
    but there is a similar requirement for the mechanical and electrical.


    Sentence (2) If a building is less than 5 storeys in building height,the parts of the building that are classified as Group C major occupancies shall be provided with thermal insulation that conforms to Table 10.2.1.1.
    Sentence (4) Buildings or parts of buildings described in Sentence 1.3.3.3.(1), Division A, that are not Group C major occupancies, shall be provided with thermal insulation between heated and unheated space, the exterior air and exterior soil in conformance with Table 10.2.1.1.B.

    These requirements will be found in a new section: 9.36. Energy Efficiency. This section will replace the insulation tables in Part 10, but the water efficiency requirements in Part 10 will remain in effect. Existing section 9.36. Secondary Suites will be renumbered as 9.37. Secondary Suites.
    We are providing a PDF of the new section 9.36. Eneregy Efficiency to allow Building Code users to become familiar with the requirements before December 19th, 2014.
  • So why are we talking about energy standards today.
    Because they are part of the Code and as professionals we have to make sure they are being met
    Reference in the Code is found under part 10
    And It is in schedule B that you are signing for it
    The snap shot of the schedule here shows the envelope requirement,
    but there is a similar requirement for the mechanical and electrical.


    Sentence (2) If a building is less than 5 storeys in building height,the parts of the building that are classified as Group C major occupancies shall be provided with thermal insulation that conforms to Table 10.2.1.1.
    Sentence (4) Buildings or parts of buildings described in Sentence 1.3.3.3.(1), Division A, that are not Group C major occupancies, shall be provided with thermal insulation between heated and unheated space, the exterior air and exterior soil in conformance with Table 10.2.1.1.B.

    These requirements will be found in a new section: 9.36. Energy Efficiency. This section will replace the insulation tables in Part 10, but the water efficiency requirements in Part 10 will remain in effect. Existing section 9.36. Secondary Suites will be renumbered as 9.37. Secondary Suites.
    We are providing a PDF of the new section 9.36. Eneregy Efficiency to allow Building Code users to become familiar with the requirements before December 19th, 2014.
  • If we look at the adoption of standards in Codes
    BCBC adopted ASHRAE in 2008, and up to now it is the 2004 version that has been in the Code
    ASHRAE has been in VBBL for more than a decade and the version we have been dealing with in the last few year is 2007
    NECB (or MNECB 1997) has not been part of Codes in BC,
    LEED, not BC codes, is where there is a reference to MNECB

    It is also interesting to note that the City of Vancouver has recently started collecting compliance documentation for ASHREA.
    This is something I believe the province is also working on.
  • Read the slide

    Continuous maintenance means that there can be updates in between versions, and that new versions come out regularly

    Applies to new buildings, addition to existing buildings, alterations to existing building, replacements of portions of existing building
  • With ASHRAE, there are 3 alternative paths for compliance
    1-prescriptive
    2-Trade-off
    3-Energy cost budget which is the Whole Building energy modeling approach
    All 3 methods require that the mandatory provisions be fulfill
    Prescriptive path and Trade off methods involves many different building systems and
    If this path is chosen, all the building systems listed here need to meet the prescriptively requirement of their respective parts
    This means that all these professionals need to work together to achieve compliance and there is a need for someone coordinating the process,
    Ultimately, if EVEN one of the building systems listed cannot meet the prescriptive requirements,
    than NONE of them can go that route and the Energy cost budget path needs to be taken.
  • Looking at the evolution of ASHRAE, if we were to consider the 2004 version as the base line,
    Although mechanical and electrical system have been evolving every version
    most of the building envelope changes happened with the 2007 version
    The suggested BE changes that were put forward for 2010 version actually got defeated
    My understanding is that the Goal for 2010 was to achieve 30% energy saving over 2004
    But I believe that without the increase of the BE requirements going into 2010, it is falling a little bit short on that
  • NECB is a Canadian Standard,
    It was developed by Natural Resources Canada and National research Council for Canada
    The latest version of this standard was in 1997, and it was called the Model National Energy Code

    LEED v4 will be a US version only though some Canadian adaptations will be accepted by USGBC. ASHRAE 2010 is the version used in LEED v4. NECB 2011 will likely be accepted as an equivalent, with some modifications. It will be announced in 3 weeks at the CaGBC conference. 
     
    People will HAVE to use v4 as of June 2015 in Canada. But they could do so earlier. 
  • Like in ASHREA, Compliance can be achieve through 3 alternative paths
    1-prescriptive
    2-Trade-off methods (here there is 2 a simple method and a detailed one)
    3-Energy simulation

    Again, just like AHSRAE, if the prescriptive path is desired, than all the building system needs to meet it
    If even one cannot, than the prescriptive path cannot be use for any of them


  • ASHREA has a list of Cities with there zones, only when a city is not listed you should look at weather data to establish the HHD
    NECB states that the Climatic values are established by the Authorities having jurisdiction, or in the absence of such, we should be using what is in the Code
    The funny part about that is that in the lower mainland we are on the at the upper limit of zone 4 and that when you start going up the hills you are in Zone 5 What about the rest of BC?
    A lot of the municipalities in ASHRAE are listed as Zone 5 including Nanaimo, Victoria, Vancouver and New West

    One of the distinction with ASHRAE is the determination of the zone as Humid (A), Dry (B) and Marine (C), which from an envelope perspective doesn’t make a difference because we still have the same U value requirements. But they may make a difference from an mechanical or energy modeling perspective
  • NECB is defined by degree days and broken into 1000 heating degree-day increments. (A heating degree day (HDD) is defined as the number of days the outside temperature is below the indoor set point temperature; for standard room temperatures these are defined in the building codes under climatic data.)ASHRAE uses a more complex system to define climate zones, intended to include heating, cooling, solar angle and latent loads. Climate zones for Canada are defined in Appendix B (Table B-2.)
    In both compliance paths the building performance requirements are defined by the climate zone, and in one location the requirements in one standard might be more stringent than in the other. For example, Victoria is ASHRAE zone 5c and NECB zone 4, while Nanaimo, which is 100 kilometres away, is ASHRAE Zone 5c but NECB zone 5. Therefore, when deciding which path to follow the climate zone must be reviewed.
  • So let’s start with ASHRAE
    Again, we will be focusing here on the envelope section of the standard
    And we will look at the prescriptive and trade-off method only
    The energy cost budget method is covered under a different traning which will be given by my colleague Christian Cianfrone (On ???)
  • If we look at the compliance paths again we see that regardless of the path chosen
    Whether it is the Prescriptive path, the BE trade-off option or the Energy Cost budget method, one need to meet the mandatory provisions
    Then there is the submittals section which is in essence the compliance documentation that you are currently required to submit to the City
    Like I mentioned earlier, The province is also working on something
    But the bottom line is, the forms are there, they are helpful tools to make sure every is addressed properly, they should be used
  • The mandatory provisions form part of the Compliance Documentations, (the form looks different than the 2007 or 2004 version but it is more or less the same)
    To be able to meet these provisions, attention should be given to every single one of them at an early stage.
    A lot of this information should actually be incorporated in the specifications
    Insulation needs to be…
    Air leakage refers to the selection and construction of the air barrier - this is part of the code already (part 5). AB needs to be Continuous, to be structurally supported and to consist of appropriate materials
    Air leakage rate are limited for glazing assemblies and doors. In general NAFS is more demanding but I encourage you to verify the requirements. Typical window is 0.2 cfm/ft2 at 75Pa in ASHREA and 0.1 in NAFS.
    And in Vancouver, and anywhere else in BC, you need a vestibule unless you meet one of the exceptions listed (among them size of lobby or using a revolving doors)
    Finally, when we are talking of U values for windows, they are the values that are determined, certified and labeled in accordance with NFRC
    The NFRC values are for specific window sizes
  • Mandatory requirements are certainly something you want to include in your specifications and design documents (Air barrier!)
    You will want to include the performance requirements for pre-fabricated assemblies (especially windows and Doors) that would include, U Values, SHGC and the air leakage limits
    There might be other standard that need to be addressed, NAFS being one of them when it comes to air leakage
    In general NAFS is more demanding but I encourage you to verify the requirements. Typical window is 0.2 cfm/ft2 at 75Pa in ASHREA and 0.1 in NAFS.
  • So 1st, lets look at the prescriptive approach… Read the slides
    That is for each space conditioning category (Residential, Non-Residential and semi-heated)
    Does that look like anything typical that is being built in downtown Vancouver? Glazing proportion of you typical downtown high-rise is probably over 70%
    So not only these 2 conditions need to be met but
    Then all components (opaque wall and roof areas, fenestration, skylight and doors) need to meet the Rvalues listed in the prescriptive tables
    Note that Spandrel in glazing is considered an opaque wall assembly and
    we will see in later why spandrels are a “no go” for the prescriptive method
  • To be able to determine the Rvalue requirements, the environmental separations need to be understood
    The lines in dark gray are typical exterior building envelope and would need to meet the full Rvalue requirement either under the residential or non-residential categories
    That would be for example between a conditioned space and the exterior or between a conditioned space and a ventilated space
    The light grey line defines walls that would have to meet the requirements of a semi-heated space
    That would be for example between a conditioned space and a semi-conditioned space or an unconditioned space, or between a Semi-heated space and the exterior
  • Read the first sentence… click
    Zones are defined in Appendix B of the standard (The zone are defined by the HDD and the ABC refers to the type of climate, in this case C is marine climate)
    Each one of the space conditioning categories are listed at the top of the table… here click
    Read the second part of the slide
    Maximum U Factor is in essence the effective thermal résistance of the assembly, including air films, or if you take 1/U it becomes the effective Rvalue
    Minimum Rated Rvalue of insulation is for the thermal resistance of the insulation only whether in the framing cavities or installed as continuous insulation inboard or outboard of the framing

    There is quite a number of these tables and the idea today is not to go over them but to give you an understanding of what information is available and where you can find it

    There is a possibility within the standard prescriptive method, it is that …. Read exception
  • These are some of the values that can be found in the standard for some components when constructed in Zone 5
    Inverted or conventional roof assemblies are fairly simple as typically we find continuous insulation on these roofs and that is what is in the table (the c.i. is for continuous insulation)
    Attics, typically wood frame , would require R38 insulation between rafters
    Mass Wall at .09 is an effective Rvalue of R11.1 (why is it lower than the continuous insulation ???)
    Steel studs at .064 is an effective Rvalue of R15.6, or from a nominal value approach we are looking at R13 batt within the 3 5/8” steel studs and 1 ½” of continuous rigid insulation
    But what do they mean by continuous insulation…

  • Just read the slide
  • Nominal R values…
    Effective R values…
    For e.g. R-20 Batt in 6”SS is about R9
    R-20 Batt in 6” wood studs is about R16
  • There are tables in the appendix A that help you with determining the U values
    For example here we have the Ufactors for steel stud assemblies,
    but there are a numbers of other tables for other types of assemblies
    We should remember that good practice for steed stud assemblies is to have at least ¼ of the insulation outboard , this for durability purposes.
    So using the base wall assembly shouldn’t really be an option
    Looking at the table above, it looks like to have a value < 0.064 (which is required for SS assemblies in residential or non-residential buildings in zone 4 et zone 5) we are looking at 1 to 2” of insulation depending on the type
    But then again, this is not considering Z girts or clips.
    If the assemblies are substantially different that what is in the table they can always be calculated
    We will look at that later in the presentation
  • This is the Ufactors for wood stud assemblies,
    Looking at the table above, it looks like to have a value < 0.051 (which is required for wood assemblies in residential buildings zone 5) we are looking at 1inch of insulation depending on the type
    Looks like exterior insulation is required … Click
    Zone 4 (R<0.064) is the only one that can have insulation installed only within the stud space
    A lot of people ask if they were to use 2 part spray foam if they would meet the requirement of .051… yes but why would you. It is very expensive, 3 passes.
  • Check the Values!!! Why are the changes happening like they do??? Why 15.6 or 18.8, why does the roof ext ins doesn’t change
    All I have put here for comparison are the Minimum rated R values of insulation for different components per Zone fro a residential building
    Zone 5: Vancouver, Victoria, Penticton and Kamloops
    Zone 6: Prince Rupert
    Zone 7: Prince George
    Zone 8: Ft Nelson
    Go through the numbers one per one
    Obviously there are more components than this, for example there are values for floors, below grade walls and slab on grade,
    And I have kind of ignored the Structural steel buildings which are also in the tables
  • Now looking at Fenestration, and remembering that we are dealing here with a building that has less the 40% window to wall ratio and less than 5% skylight to roof ratio
    Than all fenestration needs to meet a minimum U factor and solar Heat Gain Coefficient
    Read the 2 arrows
  • So if we look at the Vancouver region (zone 5) , the fenestration need to meet the following values
    Read the table
    For e.g. window-wall with a good low-e coating, argon and warm edge spacers can meet values below 0.40
    A vinyl window with the same sealed unit with be below 0.32
    Curtain wall , and espescially storefront, can vary greatly depending on if it is a structural silicone CW or the type of thermal break it incorporate, but 0.45 can be met with the right selection
    More tables can be found in the standard for the different zones,
  • So now that we have reviewed the prescriptive path, we have found out that it is somewhat restrictive
    The trade-off method allow more flexibility
    Often buildings have fenestration that exceed the 40%, that is especially through in Vancouver!!!
    Or some of the building envelope components do not quite meet the minimum R value required through the prescriptive path
    That is when the trade-off method may come in handy, as oppose to having to do the whole energy modeling
    But it needs to be understood that the trade-offs only happen between BE components,
    And to be successful, some of the BE components will have the exceed the minimum requirements to compensate for what doesn’t.
  • Read the slide
  • To demonstrate compliance using the trade-off method, in broad terms you need to:
    Do take offs
    And numbers in equations
    Software ENVStd Was not updated with the latest version of ashrae, and COMcheck does not include Canadian climate data …so these calculations now need to be done by hand
    Or if you are like me and you glaze over at the sight of an equation, than you ask someone that has more patience than you to do it

    One thing that the trade-off method does is determine the Daylighting potential using the VT. A benefit will result when the glazing used in the proposed building has a high VT.
    The VT is not taken into account with the prescriptive method
  • Easy interface, Read the user guide on how to define areas
    There is also in there a good database of values for fenestration which links to NFRC
  • Much like AHREA, NECB puts a certain limit on the fenestration
    The limit on the vertical fenestration varies depending on the HDD FDWR is the vertical fenestration and doors to wall area ratio
    It shows that up north, where it is very cold, like in Ft. Nelson if I remember well, the FDWR is limited to 20%
    Here in the lowermainland we are still looking at 40%
    The Skylight limitation is th Same as ASHRAE, i.e. 5%
    But NECB is more prescriptive than that!!
  • The reason why the penetrations can be ignored to a certain degree in the effective R value calculation is that there are very prescriptive requirements on how to deal with these penetrations, for example:

    1. Where an interior wall penetrates an exterior wall and breaks the continuity of the building envelope it should be insulated on both sides (inward or outward) to 4 times the un-insulated thickness of the penetrating wall.
    So If we have a inside concrete wall that connects to an exposed exterior concrete wall and breaks the insulation, this wall needs to be insulated inward (if it is an 8” wall e.g.) for up to 32” with the same insulation that is on the exterior wall.
    Similar accommodation has to be made if that wall goes through the roof insulation, think about a planter wall for example

    2. In another situation, where building envelope assembly in the same plane intersect but their insulation do not, one of the two insulation need to extend beyond the other one by at least 4 times the distance separating the two insulation.

    AS far as the salb is concerned, remember that you can igore it if it is less than 2% but otherwise you need to consider it
  • OK ASHREA is in Imperial, NECB is in metric , For easier comparison I converted all the numbers in imperial R values (metric U/5.678 = imperial U and R = 1/U)
    The table above applies to all types of construction it doesn’t whether the building is residential or not, or whether the walls are mass walls, steels studs or wood frame construction,
    As a comparison, ASHRAE for zone 5 residential requires the following effective R value for the walls …click And for the roofs … click
    We can see that NECB is more stringent for the walls, and somewhere in the middle for the roof
    Still R31 would require about 6inches of continuous rigid insulation above the deck, 2” or 1/3 more than what would be required by ASHRAE
  • The table above applies to all fenestration and doors, regardless if it is a residential or non-residential building or if it is a metal, wood or vinyl window.
    There are a few exception as noted
    There is no SHGC requirements
    When comparing to ASHRAE… CLICK
    We see that NECB is more stringent, at least with the metal framed windows, including curtain wall and storefront,
    And if the proportion of skylight is between 2% and 5%
    But how does this compare to the Energy efficiency act
    Metal 0.45
    Non-metal 0.35
  • ASHRAE as a category for semi-heated space in their table.
    With NECB, the insulating value depends on the delta in temperature between the two spaces
  • What is a model that conform to ASHRAE 140???
  • Read
    In other word it is a simplified energy model that doesn’t trade with the mechanical and electrical systems

  • If above 40% cannot use prescriptive, but can use trade off (to a limit). That would still allow you to use prescriptive with other building systems. However if the prescriptive or trade-off method cannot be met, then you need to model your whole building, you cannot use prescriptive.

    AND at the end of it, even the prescriptive method are fairly complex in the sense that they are open to interpretation as how to calculate R value to consider or ignore things that are not expressively in the prescriptive tables…
  • So to recap what we discussed in the standards,
  • So let’s start with ASHRAE
    Again, we will be focusing here on the envelope section of the standard
    And we will look at the prescriptive and trade-off method only
    The energy cost budget method is covered under a different traning which will be given by my colleague Christian Cianfrone (On ???)
  • How is Thermal bridging typically evaluated?
    Hand calculation for simple assemblies – clear wall
    Lab Testing (hot Box) for standard assemblies (would be hard and expensive to test every iteration) - used to valid some results
    Computer modeling - Current common methods use 2D programs such as THERM to calculate thermal bridging
    Knowing material properties, it will give you the average heat loss (U-value) through the assembly in 2D
    But this can only take you so far.
  • Probably your best Resource when it comes to U Factors (or effective R values) is thje Normative Appendix A in Ashrae 90.1
    It contains R-values for certain buildign materials (although not that many)
    But it especially contains a series of tables for different assemblies for which the r value are already calculated
  • Concrete with 1” of rigid is 0.157 or R=6.36
    Looking at the previous table for a 6” steel stud with BATT we are looking at about R15
  • It also give you the possibility to used area-weighted average as long as the assemblies have similar thermal mass or walls of same class and construction

    The area-weighted average U-Factor is based on different U-factor for each of these assemblies which is averaged over their length.
    If we are considering the prescriptive method for mass wall the requirement is U 0.080 for a residential building (or an effective R value of 12.5), the 7.3 does meet that.
  • Ok so if we are using the area weighted average to characterize thermal bridges, Are we really getting what is happening in real life
    That is easy for clear wall assemblies, and comparisons, but how do you deal with slabs and parapets and other types of anomalies
    The reality is that the effect of thermal bridge goes beyond the little portion of slab I showed you doing the area weighted average calculation
    Sometime the effect of the thermal bridge can affect area 1 to 2 m away from the anomaly, depending on how conductive the material penetrating the envelope is
    So the answer to that can only be to look at it in 3D
  • 3D modeling is done using Finite element analysis
    It can deal with … read the points
    An the good thing about 3D model, is that it can be very accurate.
    Projects we have done developeing some of this has shown vey good relationship with result of Lab tests
  • So with this in mind, lets look at the typical lower mainland construction
    Wood frame is fairly easy, non-combustible construction however is more complicated in part because of:
    -the conductivity of steel
    -the way the are often built – think about exposed concrete and

    The amount of thermal bridges is significant and a lot of the details don’t easily conform to the prescriptive approach of either standards
  • The type of details we are finding on concrete towers are pretty much like this
    Window wall and interior insulated concrete

    And now that we are seeing more and more exterior insulated construction
    Sub-girts, and the likes, still having the deal with the slabs in one way or another
    -how much heat are we loosing through a girt at the slab vs a girt at the steel stud?
  • But how do you deal with this in 2D

  • This graph shows the effective R-values of the previous steel stud assemblies for varying amount of exterior insulation, along with the minimum requirements from ASHRAE 90.1-2010 and NECB 2011
    The straight light blue line here shows what ASHRAE says the value of the wall would be with continuous exterior insulation.
    As you can see, with cladding attachments, the effective assembly U-values fall short of that to varying degrees.

    This indicates that it may be very difficult to reach prescriptive requirements in most climate zones with solely exterior insulation.
  • You can see with the spray foam case, the stud cavity is much closer to the room temperature and the frame temp is lowered. So how does that relate in terms of thermal effectiveness?
  • Here you can see that adding an R-11 spray foam only, on average, adds about an R-4 to the assembly
    This is understandable since there is just so much aluminum in a curtain wall system where heat can bypass the backpan and sprayfoam.
    The next question designers have to consider is, with that much spray foam and only getting back R-4, is it financially worth it? In some cases, in order to meet code requirements, they may have to go that route.
  • I have presented 2 example aboev of results for assemblies using a finite element 3D model
    Probably your best Resource when it comes to U Factors (or effective R values) is thje Normative Appendix A in Ashrae 90.1
    It contains R-values for certain buildign materials (although not that many)
    But it especially contains a series of tables for different assemblies for which the r value are already calculated
  • Offcial Launch Oct 16
  • So let’s start with ASHRAE
    Again, we will be focusing here on the envelope section of the standard
    And we will look at the prescriptive and trade-off method only
    The energy cost budget method is covered under a different traning which will be given by my colleague Christian Cianfrone (On ???)
  • 2014 BCBC Envelope Compliance - ASHRAE 90.1 and NECB

    1. 1. October 8, 2014 Envelope Compliance ASHRAE 90.1 and NECB 2011
    2. 2. OVERVIEW  Code requirements and the Standards  Broad overview of the Standards  ASHRAE 90.1 prescriptive requirements 2 and trade-off method for Envelope  NECB Prescriptive requirements and trade-off method for Envelope  Summary comparison of the prescriptive requirements and what it means in the BC building context  Looking at different methods of accounting for thermal bridging
    3. 3. BCBC 2012 3
    4. 4. VANCOUVER BUILDING BY-LAW 4
    5. 5. STANDARDS IN CODES 5 ASHRAE 90.1 2004 – Previous BCBC ASHRAE 90.1 2007 – Previous VBBL ASHRAE 90.1 2010 & NECB 2011 – Current BCBC and VBBL
    6. 6. ASHRAE 90.1 2010 6 WHO ARE THEY? American Society of Heating Refrigeration and Air-conditioning Engineers WHAT IS THE STANDARD? First addition developed in 1970 In 1999 the standard was put into continuous maintenance Applies to all commercial buildings and MURBS greater than 3 stories.
    7. 7. ASHRAE 90.1 OVERVIEW 7 ALTERNATIVE PATHS FOR COMPLIANCE Prescriptive Trade-off Energy cost budget PRESCRIPTIVE PATH (OR TRADE-OFF) REQUIRE THAT ALL PARTS OF THE STANDARD BE MET: Part 5 - Building envelope Part 6 - Heating, ventilating and air-conditioning Part 7 - Service water heating Part 8 - Power Part 9 - Lighting Mandatory Part 10 - Other equipment Provisions
    8. 8. ASHRAE 90.1 OVERVIEW 8 ASHRAE 2004 Baseline ASHRAE 2007 Increased BE requirements ASHRAE 2010 No major changes in BE requirements
    9. 9. NECB 2011  Developed by Natural Resources 9 Canada & the National Research Council for Canada  What is the Standard?  Last version was in 1997 (MNECB)  Design intent was to be roughly equivalent to ASHRAE 90.1 2010  Applies to new buildings (except part 9), additions to existing building, but silent on renovations  Before now, not referenced in BCBC or VBBL  MNECB is referenced in LEED
    10. 10. NECB OVERVIEW 10 ALTERNATIVE PATHS FOR COMPLIANCE  Prescriptive  Trade-off (simple or detailed)  Energy simulation (building energy compliance) PRESCRIPTIVE PATH (OR TRADE-OFF) REQUIRE THAT ALL PARTS OF THE STANDARD BE MET:  Part 3 – Building envelope  Part 4 – Lighting  Part 5 – Heating, ventilating and air-conditioning systems  Part 6 – Service water heating systems  Part 7 – Electrical power systems and motors
    11. 11. ZONES AND HEATING DEGREE DAYS (HDD) 11 ASHRAE 90.1 Climate zones for BC
    12. 12. ZONES AND HEATING DEGREE DAYS (HDD) 12
    13. 13. ASHRAE 90.1 2010 BUILDING ENVELOPE
    14. 14. ASHRAE 90.1- BUILDING ENVELOPE 14
    15. 15. ASHRAE 90.1- MANDATORY PROVISIONS THIS MEANS THAT THE BUILDING SHOULD BE DESIGNED TO MEET THESE PROVISIONS: Insulation Air leakage • Air-barrier selection and design • Limit to fenestration and doors including cargo doors • Vestibule Fenestration and Doors values • NFRC 15
    16. 16. ASHRAE 90.1 MANDATORY PROVISIONS 16 ASHREA 90.1 Air leakage limits NAFS Air Leakage limits ASHRAE Type Limit Glazed Swinging entrance door & revolving doors 1.0 cfm/ft2 at 1.57psf Curtain wall & Storefront 0.06cfm/ft2 at 1.57psf Other products 0.2cfm/ft2 at 1.57psf or 0.3 cfm/ft2 at 6.24psf NAFS defines air leakage by performance class (R, LC, CW and AW) and air infiltration / exfiltration levels (A2, A3 and Fixed) and can be more stringent: Fixed as low as 0.2 L/s.m2 at 300Pa (or 0.04cfm/ft2 at 6.24psf) Operable as low as 0.5 L/s.m2 at 300Pa (or 0.1cfm/ft2 at 6.24psf)
    17. 17. ASHRAE 90.1 PRESCRIPTIVE METHOD 17 THE PRESCRIPTIVE METHOD CAN ONLY BE USED IF: The vertical fenestration ≤ 40% of Gross wall Area The skylight fenestration ≤ 5% of gross roof area
    18. 18. ASHRAE 90.1 - OPAQUE AREAS  For conditioned spaces the 18 exterior building envelope shall comply with, to either: the residential or the non-residential requirements in the tables  For semi-heated spaces the semi-exterior building envelope needs to comply with the requirements in the tables
    19. 19. ASHRAE 90.1 - PRESCRIPTIVE OPAQUE AREAS 19 THE TABLES CONTAINING THE THERMAL PERFORMANCE REQUIREMENTS ARE PROVIDED IN THE STANDARD, BY CLIMATIC ZONES, AND LOOK LIKE THIS: For all opaque elements (except doors) compliance should be demonstrated by the following methods:  Maximum U-factors, C-factors or F-factors for the entire assembly  Minimum rated R values of insulation Exception: For multiple assemblies within a single class of construction for a single conditioning space, weighed average can be used.
    20. 20. ASHRAE 90.1 PRESCRIPTIVE OPAQUE AREAS 20 Components Zone 5 Non-Residential Residential Semi-Heated U factor R value U factor R value U factor R value Roof - insulation above deck 0.048 (R20.8) 20.0c.i. 0.048 (R20.8) 20.0c.i. 0.119 (R8.4) 7.6c.i. Roof - Attic 0.027 (R37.0) 38.0 0.027 (R37.0) 38.0 0.053 (R18.9) 19.0 Walls - Mass 0.090 (R11.1) 11.4c.i. 0.080 (R12.5) 13.3c.i. 0.151 (R6.6) 5.7c.i. Walls - Steel framed 0.064 (R15.6) 13.0+7.5c.i. 0.064 (R15.6) 13.0+7.5c.i. 0.124 (R8.1) 13.0 Walls - Wood framed 0.064 (R15.6) 13.0+3.8c.i. 0.051 (R19.6) 13.0+7.5c.i. 0.089 (R11.2) 13.0
    21. 21. ASHRAE 90.1 PRESCRIPTIVE - OPAQUE AREAS 21 SO THAT MEANS:  If there is more than nails or screws going through the insulation, it is not continuous  If there are studs, girts, clips, even brick ties they need to be accounted for.  This can be done by calculating the effective U (or R) values of these assemblies
    22. 22. ASHRAE 90.1 PRESCRIPTIVE - OPAQUE AREAS 22 NOMINAL R VALUES Rated R values which do not take into account framing or other element interrupting the insulation vs. EFFECTIVE R VALUES Calculated R values which allows for the impact of thermal bridges
    23. 23. ASHRAE 90.1 PRESCRIPTIVE - OPAQUE AREAS 23 Zone 4&5 = 0.064
    24. 24. ASHRAE 90.1 PRESCRIPTIVE - OPAQUE AREAS 24 Zone 4 = 0.064 Zone 5 = 0.051
    25. 25. ASHRAE 90.1 PRESCRIPTIVE - OPAQUE AREAS 25 Components Residential R values Zone 4 Zone 5 Zone 6 Zone 7 Zone 8 Roof - insulation above deck 20.0c.i. 20.0c.i. 20.0c.i. 20.0c.i. 20.0c.i. Roof - Attic 38.0 38.0 38.0 38.0 49.0 Walls - Mass 11.4c.i. 13.3c.i. 15.2c.i. 15.2c.i. 25.0c.i. Walls - Steel framed 13.0+7.5c.i. 13.0+7.5c.i. 13.0+7.5c.i. 13.0+15.6c.i. 13.0+18.8c.i. Walls - Wood framed 13.0+3.8c.i. 13.0+7.5c.i. 13.0+7.5c.i. 13.0+7.5c.i. 13.0+15.6c.i.
    26. 26. ASHRAE 90.1 PRESCRIPTIVE - FENESTRATION Windows <40% of gross wall area and Skylights <5% gross roof area 26 All fenestration compliance shall be demonstrated through meeting: • U factor no greater than the prescriptive requirements • SHGC no greater than the prescriptive requirements If there are multiple assemblies, compliance shall be based on an area-weighted average U-factor or SHGC (for a single space-conditioning and within a single class of construction). The SHGC can be reduced using a multiplier when a permanent projection provides shading for the window
    27. 27. ASHRAE 90.1 PRESCRIPTIVE - FENESTRATION 27 Components Zone 5 Residential Non-Residential Semi-Heated U factor SHGC U factor SHGC U factor SHGC Non-Metal Framing 0.35 0.40 for all 0.35 0.40 for all 1.20 0.40 for all Metal Framing (curtain wall and storefront) 0.45 0.45 1.20 Metal Framing (entrance doors) 0.80 0.80 1.20 Metal Framing (operable and fixed windows, non-entrance doors) 0.55 0.55 1.20 Skylight (glass, without curb) 0-2% 0.69 0.49 0.69 0.49 1.36 NR 2-5% 0.39 0.39 NR
    28. 28. ASHRAE 90.1 TRADE-OFF 28 The trade-off method allows greater flexibility when some of the building envelope components are not meeting: • The basic requirements for the Prescriptive method (e.g. > 40% window to wall ratio and/or >5% skylight to roof ratio) • The prescriptive R or U values • Trade-offs are made between any building envelope components (but just building envelope component) • It implies that some of the building envelope components exceed the minimum requirements • Schedules of operation, lighting power, equipment power, occupant density, and mechanical systems need to be the same for both the proposed building and the base building
    29. 29. ASHRAE 90.1 TRADE-OFF 29 THE BUILDING ENVELOPE COMPLIES WHEN: Envelope performance factor of proposed building Envelope performance factor of base building ≤ The base building is a building that has 40% fenestration to gross wall area and for which all BE components meet the prescriptive minimum U value The envelope performance factor is calculated using the information contained in normative appendix C
    30. 30. ASHRAE 90.1 TRADE-OFF 30 Need to :  Do take-offs for all the different BE components i.e. floor, roof, wall and fenestration assemblies for every space-conditioning category and every orientation.  Evaluate the U values of each component including SHGC and VT for fenestration.  Enter all the numbers into a series of equations that you can find in normative Appendix C*. COMcheck * (Now has Canadian climate data). Axis – Raymond Letkeman Architects
    31. 31. COMCHECK 31
    32. 32. COMCHECK 32
    33. 33. NECB 2011 BUILDING ENVELOPE
    34. 34. NECB 34
    35. 35. NECB - MANDATORY PROVISIONS 35 NO SPECIFIC MANDATORY PROVISIONS But more specific than ASHRAE on how to deal with effect of structural members that may partially and completely penetrate the envelope In the prescriptive requirements, we find that : Insulation should be installed in a manner that avoids affecting its R value (convection, wetting, etc.). Insulation value required depends on zone, assembly (wall, roof or floor) and location (above or below grade or spaces heated to different temperature) Air leakage should be controlled, including at fenestration and doors, which have limits of air leakage allowable A vestibule is likely required
    36. 36. NECB - PRESCRIPTIVE METHOD THE PRESCRIPTIVE METHOD CAN ONLY 36 BE USED IF: FDWR ≤ 0.40 for HDD < 4000 FDWR ≤(2000- 0.2*HDD) 3000 for 4000 ≤ HDD ≤ 7000 FDWR ≤ 0.20 for HDD > 7000 & The skylight fenestration ≤ 5% of gross roof area
    37. 37. NECB - THERMAL BRIDGING THERMAL BRIDGING 37 CREATED BY STRUCTURAL MEMBERS The thermal bridging effect of closely spaced repetitive structural members (e.g. studs) and of ancillary members (e.g. sill and plates) should be taken into account. The thermal bridging of major structural elements that are parallel to the building envelope can be ignored, provided that they do not increase the thermal transmittance to more than twice than permitted. The thermal bridging of major structural elements that must penetrate the building envelope need not be taken into account, provided that the sum of the areas is less than 2% of the above ground building envelope. Service equipment, shelf angle, ties and associate fasteners as well as minor structural members need not be taken into account!!!
    38. 38. NECB PRESCRIPTIVE INSULATION 38 The prescriptive method requires: 4xW W W 4xW
    39. 39. NECB PRESCRIPTIVEWALLS ABOVE GRADE  No difference between residential and non-residential  No difference between the different type of construction 39 Assemblies Any Occupancy R values (effective) Zone 4 Zone 5 Zone 6 Zone 7 Zone 8 Walls 18 20.4 23 27 31 Roofs 25 31 31 35 40 Floors 25 31 31 35 40 Walls - mass 11.4 Walls - steel framed 15.6 Walls - wood framed 19.6 Roofs - insulation above 20.8 Roofs - attic 37.0
    40. 40. NECB PRESCRIPTIVE FENESTRATION AND DOORS 40 Components U values (effective) Zone 4 Zone 5 Zone 6 Zone 7 Zone 8 All Fenestration 0.42 0.39 0.39 0.39 0.28 All Doors 0.42 0.39 0.39 0.39 0.28  No difference between residential and non-residential  No difference between the different type of assemblies  No SHGC requirements  Exceptions:  Skylights that represent < 2% of gross roof area can have a thermal transmittance of no more than 0.60  Doors that represent < 2% of gross wall area can have a thermal transmittance of no more than 0.77 Non-metal 0.35 Metal framing (CW) 0.45 Metal framing (others) 0.55 Entrance doors 0.80 Skylights 0.58
    41. 41. NECB - PRESCRIPTIVE METHOD 41
    42. 42. NECB - TRADE-OFF METHODS 42 THERE ARE 2 TRADE-OFF PATHS: Simple trade-off calculations Detailed trade-off path Proposed Bldg Envelope Annual Energy Consumption Reference Bldg Envelope energy target ≤ Calculation are done using an energy model with set requirements ≤ Proposed building Reference building
    43. 43. NECB - DETAILED TRADE-OFF METHOD THE DETAILED METHOD CONSISTS OF: 43 Same building size and shape, roof slope, and building orientation for the proposed and reference building Same assumptions for space heating and cooling Allowable fenestration and door areas in the proposed building can be varied, while it is set per the prescriptive requirements in the reference building Take into account thermal mass and SHGC Air leakage and solar absorbance cannot be varied
    44. 44. COMPARISON OF 2 STANDARDS 44 ASHRAE 90.1 2010 NECB 2011 Mandatory requirements Yes, for all methods Not for energy modeling Prescriptive requirements Generally less demanding R values Stringent, specific • Framing Take into account Take into account • Structure Not clear Specific (if this then…) • Cladding attachments Take into account Some can be ignored • Service penetrations Ignore Specific (if this then…) • Walls More categories Less categories • Fenestration & doors More categories Less categories Trade-off methods Complex, no benefit if FDWR <40% Simple or software Benefit if FDWR <40%
    45. 45. OVERALL 45 Prescriptive method, for either standard, is for simpler buildings Trade-off method may get you the desired result, but cannot do anything for you when most of the BE components are below
    46. 46. CONCLUSION REGARDING THE STANDARDS  Wood frame is well suited for prescriptive but: 46  New standards will generally require exterior insulation to meet the max U-factor with 2x6 residential  Only zone 4 in ASHRAE (but not in NEBC) could do without exterior insulation in residential  For non-combustible building, the prescriptive method is not a likely candidate  This is especially true for exposed concrete tower and buildings with high window/wall ratio  Exterior insulated assemblies can probably meet it but structure penetrating through (balcony slabs, parapet, etc.) need to be taken into account  The trade-off methods is an option  NECB simplified is the easiest but not necessarily best  You need to have something to trade off with  Glazing ratio has the biggest impact and it is hard to make up for it with insulation
    47. 47. EFFECTIVE R VALUES
    48. 48. CONSIDERING THERMAL BRIDGING Computer Modeling Hand Calculations  Series calculation method  Parallel path calculation method  Isothermal planes method Lab Measurement 48
    49. 49. ACCEPTABLE CALCULATION METHODS 49 Construction Classes Testing or Modeling Series calculation method Parallel path calculation method Isothermal planes method Roofs Insulation above deck P P Attic (wood joists) P P Attic (steel joists) P P Walls Mass P P Steel framed P P Wood framed P P
    50. 50. WHERE TO FIND INFORMATION 50 Resource material ASHRAE 90.1 Appendix A
    51. 51. TABLES –WOOD FRAMED WALLS 51
    52. 52. TABLES – STEEL FRAMED WALLS 52
    53. 53. TABLES – MASS WALLS 53 If adding steel studs with Batt , table 9.2B can be used (as per previous)
    54. 54. AREA WEIGHTED AVERAGE (SAME CLASS) 54 R1.25 for 9” slab edge R15 for 8’3” wall 1 푅 = 0.75 × 1 1.25 + 8.25 × 1 15 9 푅 ≅ 7.8
    55. 55. L2,par apet Lro of HEAT LOSS 55
    56. 56. 3D MODELING  Time-transient dynamic 3D heat 56 transfer model that is capable of accurately modeling:  Complex geometries  Radiation through air spaces  Radiation to the interior and exterior space  Conduction of small areas of highly thermal conductive materials through larger areas of highly insulating materials  Calibrate the model using existing lab testing
    57. 57. COMMON CONSTRUCTION 57
    58. 58. COMMON CONSTRUCTION DETAILS 58
    59. 59. CLADDING ATTACHMENTS Horizontal Vertical Z-Girts Z-Girts Mixed Z-Girts Intermittent Z-Girts 59
    60. 60. EFFECT OF THERMAL BRIDGING IN 3D 60 NECB 2011 ASHRAE 90.1 2010 * Assembly does not include any interior insulation but the wall cavity and different materials offer additional insulating value. *
    61. 61. IMPROVED GIRT SYSTEMS 61
    62. 62. CLIP SYSTEMS 62
    63. 63. Spray Foam GLAZING SPANDREL AREAS 63 No Spray Foam
    64. 64. GLAZING SPANDREL AREAS 3.4 4.2 4.8 5.0 7.4 8.2 8.8 9.1 10 9 8 7 6 5 4 3 2 1 0 0 5 10 15 20 25 30 Spandrel Section R Value Back Pan Insulation Detail 22 (Air in Stud Cavity) Detail 23 (Spray Foam in Stud Cavity) 64
    65. 65. CONCRETEWALLS 65 ≈ ≈
    66. 66. CONCRETE WALLS 66
    67. 67. CONSIDERING THERMAL BRIDGING 67 Resource material Building Envelope Thermal Bridging Guide
    68. 68. BE THERMAL BRIDGING GUIDE  ASHRAE 90.1 does not 68 address major thermal bridges such as slab edges, shelf angles, parapets, flashings at window perimeters, etc.  In practice, these details are largely overlooked.
    69. 69. WHAT IS THE GUIDE 69  Started with AHSRAE 1635RP project when linear transmittance got introduced to North America  BE Thermal Guide looked at over 400 details familiar to the BC MURB market including:
    70. 70. CONCEPTUAL LEAP 70 Types of Transmittances Clear Field Linear Point o   U psi chi
    71. 71. LINEAR TRANSMITTANCE 71 oQ Q sla b Q Additional heat loss due to the slab
    72. 72. OVERVIEW OF THE GUIDE 72  Introduction  Part 1 Building Envelope Thermal Analysis (BETA) Guide  Part 2 Energy and Cost Analysis  Part 3 Significance, Insights, and Next Steps  Appendix A Material Data Catalogue  Appendix B Thermal Data Catalogue  Appendix C Energy Modeling Analysis and Results  Appendix D Construction Costs  Appendix E Cost Benefit Analysis
    73. 73. RESULTS – APPENDIX B 73
    74. 74. FROM BAD TO BETTER 74
    75. 75. HOW MUCH EXTRA LOST CAN DETAILS ADD?  Standard 90.1 Prescriptive Requirements for Zone 5 Non- 75 Residential  Mass Wall, U-0.090 or R-11.4 ci  Steel-Framed Wall, U-0.064 or R-13 + R-7.5 ci Mass wall with R-12 insulation inboard Steel stud with R-10 exterior insulation and horizontal girts at 24”o.c and R-12 in the stud cavity
    76. 76. EXAMPLE BUILDING  Mass Concrete Wall 76  Exposed concrete slab  Un-insulated concrete parapet  Punched window in concrete opening  Steel-Framed Wall  Exterior insulated structural steel floor intersection  Insulated steel stud parapet  Punched window in steel stud opening with perimeter flashing  10 floors  20% glazing  No Balconies  Standard details
    77. 77. IMPACT OF DETAILS Transmittance Type 77 Mass Concrete Wall Exterior Insulated Steel Stud Heat Loss (BTU/hr oF) % of Total Heat Loss (BTU/hr oF) % of Total Clear Wall 118 52 % 98 67 % Slab 92 40% 24 17 % Parapet 9 4% 4 3 % Window transition 8 4% 19 13 % Total 227 100 % 145 100 %
    78. 78. IMPACT OF DETAILS Performance Metric 78 Mass Concrete Wall Exterior Insulated Steel Stud ASHRAE Prescriptive Requirements Overall Performance ASHRAE Prescriptive Requirements Overall Performance U (Btu/hrft2oF) 0.09 0.14 0.064 0.091 “Effective” R (hr ft2 oF/BTU) R-11 R-7 R-15.6 R-11 % Difference 44% 35%
    79. 79. IMPACT OF DETAILS 79 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Additional Contribution to Space Heating Energy (GJ/m2 of Floor Area) Clear Wall Only Including Poor Details Including Efficient Details Details can have a greater impact More Insulation is not the silver bullet
    80. 80. CONCLUSION  Details such as slab 80 penetration are easy to account for in calculation  Codes do not yet take into account details such as window transitions  It will likely become increasingly more difficult to ignore thermal bridging at intersections of assemblies  Move beyond simply adding “more insulation”
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    82. 82. CORPORATE OVERVIEW  Established in 1946  MHGI = MHL + MHC  Technical divisions  16 offices across North America  Over 750 employees Our Vision To be the first call for engineering solutions that make a difference 82
    83. 83. MORRISON HERSHFIELD GROUP INC. 83 Morrison Hershfield Limited Canada (580 staff) Technical Divisions:  Buildings & Facilities  Infrastructure & Transportation  Industrial Offices:  Vancouver, Victoria & Nanaimo, BC  Calgary and Edmonton AB  Toronto, Burlington and Ottawa ON  St. John’s, NL
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