The following comments have been submitted:
Comment #1Page Number: 6Paragraph / Figure / Table / Note: 3Comment Intent: ObjectionComment Type: EditorialComment: Using a single definition for attic introduces excessive ambiguity and repetition of qualifiers. Providing multiple definitions would be beneificial. Proposed Change: Attached Dwelling Unit – A Dwelling Unit sharing demising walls, floors, ceilings, or common corridors with another Dwelling Unit or Occupiable Space. Attic – A space volume below between the roof assembly and the ceiling that is not included in the Conditioned Floor Area. Attics may be either vVented Attics or air sealed.[1] Air sealed attics may be either Finished Attics, or Unfinished Sealed Attic. Blower Fan – The fan inside the equipment of a Forced-Air HVAC System that forces the heated and/or cooled air to be distributed within a Dwelling. Commercial Building – All buildings that are not included in the definition of Residential Buildings. Compartmentalization Boundary – The surface that bounds the Infiltration Volume of the Dwelling Unit. Conditioned Floor Area (CFA)[2] – The floor area of the Conditioned Space Volume within a building or Dwelling Unit, not including the floor area of Attics or, crawlspaces, and basements below air sealed and insulated floors. The following specific spaces are addressed to ensure consistent application of this definition: The CFA shall include the floor area of the full width of a wall assembly that is within the Conditioned Space Volume. Exception: If the subject Dwelling Unit shares a wall assembly[3] with another Dwelling Unit, then the CFA of the subject Dwelling Unit shall extend to the midpoint of that shared wall. The CFA shall include the floor area of a basement only if it is contiguous with and dedicated[4] to the subject Dwelling Unit and the party conducting evaluations has either: - Obtained an ACCA Manual J, S, and either B or D report and verified that both the heating and cooling equipment and distribution system are designed to offset the entire design load of the volume; or - Verified through visual inspection that both the heating and cooling equipment and distribution system serve the volume and, in the judgment of the party conducting evaluations, are capable of maintaining space conditions at 78°F (26°C) for cooling and 68°F (20°C) for heating. The CFA shall exclude the floor area of a garage even when it is conditioned. The CFA shall exclude the floor area of a thermally isolated sunroom. The CFA shall exclude the floor area of an Vented Attic or Unfinished Sealed Attic.[5]. The CFA shall exclude the floor area of a crawlspace even when it is Conditioned Space Volume. Conditioned Space Volume (CSV)[6] – The volume within a building or Dwelling Unit serviced by a space heating or cooling system designed to maintain space conditions at 78°F (26°C) for cooling and 68°F (20°C) for heating. The following specific spaces are addressed to ensure consistent application of this definition: If the volume both above and below a floor assembly meets this definition and is part of the subject Dwelling Unit, then the CSV shall include the volume of the full depth of the floor assembly. Otherwise, the volume of the full depth of the floor assembly shall be excluded. Exception: The wall height used to determine the volume of the volume shall extend from the finished floor to the bottom surface of the floor decking above the subject Dwelling Unit for all floors other than the top floor level. For Dwelling Units on the top floor, this dimension shall extend from the top surface of the finished floor to the interior surface of the enclosure air barrier. If the volume of at least one of the spaces horizontally adjacent to a wall assembly meets this definition and that volume is part of the subject Dwelling Unit, CSV shall include the then the volume of the full width of the wall assembly. Otherwise, the volume of the full width of the wall assembly shall be excluded. Exception: If the subject Dwelling Unit shares a wall assembly[7] with another Dwelling Unit, then the CSV of the subject Dwelling Unit shall include half the volume of the full width of that shared wall assembly. The CSV shall exclude the volume of a garage even when it is conditioned. The CSV shall exclude the volume of a thermally isolated sunroom. The CSV shall include the volume of an an Unfinished Sealed Attic crawlspace, a basement only if it is contiguous with and dedicated[8] to the subject Dwelling Unit and the party conducting evaluations has either: - Obtained an ACCA Manual J, S, and either B or D report and verified that both the heating and cooling equipment and distribution system are designed to offset the entire design load of the volume; or - Verified through visual inspection that both the heating and cooling equipment and distribution system serve the volume and, in the judgment of the party conducting evaluations, are capable of maintaining space conditions at 78°F (26°C) for cooling and 68°F (20°C) for heating. The CSV shall include the volume of an adjacent mechanical closet, regardless of access location, only if it is contiguous with and dedicated5 to the subject Dwelling Unit, only includes equipment serving the subject Dwelling Unit, and the party conducting evaluations has either: - Obtained an ACCA Manual J, S, and either B or D report and verified that both the heating and cooling equipment and distribution system are designed to offset the entire design load of the volume; or - Verified through visual inspection that both the heating and cooling equipment and distribution system serve the volume and, in the judgment of the party conducting evaluations, are capable of maintaining space conditions at 78°F (26°C) for cooling and 68°F (20°C) for heating. Detached Dwelling Unit – A Dwelling Unit that does not meet the definition of Attached Dwelling Unit. Dwelling – Any building that contains one or two Dwelling Units used, intended, or designed to be built, used, rented, leased, let or hired out to be occupied, or that are occupied for living purposes. Dwelling Unit – A single unit providing complete, independent living facilities for one or more persons, including permanent provisions for living, sleeping, eating, cooking, and sanitation. Dwelling Unit Mechanical Ventilation System – A Ventilation system, operating continuously or through a programmed intermittent schedule, consisting of powered Ventilation equipment,[9] related mechanical components,[10] and automated control devices that provides Dwelling Unit Ventilation at a known or measured airflow rate. Exhaust Ventilation System (Exhaust System) – One or more fans that remove air from the Dwelling Unit, causing outdoor air to enter by Ventilation inlets or normal leakage paths through the Dwelling Unit envelope. Forced-Air HVAC System – A type of HVAC System that incorporates a Blower Fan to move conditioned air. Finished Attic – Conditioned Space Volume that is intended for human activities, including but not limited to those for living, sleeping, dining, or cooking as well as toilets, closets, halls, utility areas and above the main Dwelling Unit. For example the upper floor of a ‘Cape Cod’ home shall be considered a Finished attic. The Finished Attic shall be included in the Conditioned Floor Area and Conditioned Space Volume. HVAC System – Cooling-only, heating-only, or combined cooling-heating equipment, including any supply and/or return distribution systems. Infiltration Volume[11] – The sum of the Conditioned Space Volume of the subject Dwelling Unit, and plus the Conditioned Space Volume and Unconditioned Space Volume of the following adjacent spaces if included[12] during the airtightness measurement of the enclosure: Attics, crawlspaces and the full depth of their floor assemblies above, basements and the full depth of their floor assemblies above, and adjacent mechanical closets and the full width of their wall assemblies between them and the subject Dwelling Unit Occupiable Space – A room or enclosed space designed for human occupancy in which individuals congregate for amusement, educational or similar purposes or in which occupants are engaged at labor, and which is equipped with means of egress and light and Ventilation facilities meeting the requirements of this standard. Residential Building – Includes detached one-family Dwellings and, two-family Dwellings and multiple single-family Dwellings (Townhouses) and Group R-2, R-3, and R-4 buildings three stories or less in height above grade plane.[13] Shall – As used in this Standard, the word “shall” means that the action specified is mandatory and shall be accomplished by the responsible party. Sleeping Unit – A room or space in which people sleep, which can also include permanent provisions for living, eating, and either sanitation or kitchen facilities but not both. Such rooms and spaces that are also part of a Dwelling Unit are not Sleeping Units. Townhouse – A single-family Dwelling Unit constructed in a group of three or more attached units in which each unit extends from the foundation to roof and with open space on at least two sides. Unconditioned Space Volume[14] – The volume within a building or Dwelling Unit that is not Conditioned Space Volume but which contains heat sources or sinks that influence the temperature of the area or room. The following specific spaces are addressed to ensure consistent application of this definition for inclusion in Unconditioned Space Volume: If either one or both of the volumes above and below a floor assembly is Unconditioned Space Volume, then the volume of the full depth of the floor assembly shall be included. If the volume of both of the spaces horizontally adjacent to a wall assembly are Unconditioned Space Volume, then the volume of the full width of the wall assembly shall be included. Exception: If the volume of one of the spaces horizontally adjacent to a wall assembly is a Dwelling Unit other than the subject Dwelling Unit, then the volume of the full width of that wall assembly shall be evenly divided between both adjacent Dwelling Units. The volume of an attached garage shall be included even when it is conditioned. The volume of a thermally isolated sunroom shall be included. The volume of an Attic a crawlspace, or a basement shall be included unless it meets the definition of Conditioned Space Volume. Unfinished Sealed Attic – An unoccupied Attic that is not vented. This space shall not be included in the Conditioned Floor Area, but may be included in the Conditioned Space Volume (CSV) provided it meets the requirements laid out in the definition of CSV. Vented Attic – An attic that does not meet the criteria of either a Finished Attic or an Unfinished Sealed Attic and therefore is not included in either the Conditioned Floor Area or Conditioned Space Volume. Ventilation – The process of supplying outdoor air to or removing indoor air from a Dwelling Unit by natural or mechanical means. Such air may or may not have been conditioned. Whole-House Fan – A forced air system consisting of a fan or blower that exhausts at least 5 ACH of indoor air to the outdoors, thereby drawing outdoor air into a home through open windows and doors for the purpose of cooling the home. [1] (Normative Note) Conditioned Space Volume that is intended for human activities, including but not limited to those for living, sleeping, dining, or cooking as well as toilets, closets, halls, utility areas and above the main Dwelling Unit, (for example a ‘Cape Cod’ home), is not considered Attic space and shall be included in the Conditioned Floor Area. [2] (Informative Note) Informative Annex A contains a table that summarizes parts of a Dwelling Unit that are included in CFA. [3] (Informative Note) For example, a common or demising wall. [4] (Informative Note) That is, it does not span multiple Dwelling Units undivided. [5] (Informative Note) Conditioned Space Volume that is intended for human activities (e.g., for living, sleeping, dining, or cooking; as well as toilets, closets, halls, utility areas, and laundry areas) and above the main Dwelling Unit, such as in a ‘Cape Cod’ home, is not considered Attic space and can be included in the Conditioned Floor Area. [6] (Informative Note) Informative Annex A has a table that summarizes parts of a Dwelling Unit that are included in Conditioned Space Volume. [7] (Informative Note) For example, a common or demising wall. [8] (Informative Note) That is, it does not span multiple Dwelling Units undivided. [9] (Informative Note) Such as motor-driven fans and blowers. [10] (Informative Note) Such as ducts, inlets, dampers, or filters. [11] (Informative Note) Informative Annex A has a table that summarizes parts of a Dwelling Unit that are included in Infiltration Volume. [12] (Informative Note) Sections 4.2.4, 4.2.5, 4.2.6, and 4.2.7 define whether these adjacent spaces are to be included in Infiltration Volume. [13] (Normative Note) The definition of Residential Building corresponds to the IECC definition of Residential Building. The Occupancy Groups R-2, R-3 and R-4 are as established by the International Building Code. [14] (Informative Note) Informative Annex A has a table that summarizes parts of a Dwelling Unit that are included in Unconditioned Space Volume.
Using a single definition for attic introduces excessive ambiguity and repetition of qualifiers. Providing multiple definitions would be beneificial.
Attached Dwelling Unit – A Dwelling Unit sharing demising walls, floors, ceilings, or common corridors with another Dwelling Unit or Occupiable Space.
Attic – A space volume below between the roof assembly and the ceiling that is not included in the Conditioned Floor Area. Attics may be either vVented Attics or air sealed.[1]
Air sealed attics may be either Finished Attics, or Unfinished Sealed Attic.
Blower Fan – The fan inside the equipment of a Forced-Air HVAC System that forces the heated and/or cooled air to be distributed within a Dwelling.
Commercial Building – All buildings that are not included in the definition of Residential Buildings.
Compartmentalization Boundary – The surface that bounds the Infiltration Volume of the Dwelling Unit.
Conditioned Floor Area (CFA)[2] – The floor area of the Conditioned Space Volume within a building or Dwelling Unit, not including the floor area of Attics or, crawlspaces, and basements below air sealed and insulated floors. The following specific spaces are addressed to ensure consistent application of this definition:
Exception: If the subject Dwelling Unit shares a wall assembly[3] with another Dwelling Unit, then the CFA of the subject Dwelling Unit shall extend to the midpoint of that shared wall.
- Obtained an ACCA Manual J, S, and either B or D report and verified that both the heating and cooling equipment and distribution system are designed to offset the entire design load of the volume; or
- Verified through visual inspection that both the heating and cooling equipment and distribution system serve the volume and, in the judgment of the party conducting evaluations, are capable of maintaining space conditions at 78°F (26°C) for cooling and 68°F (20°C) for heating.
Conditioned Space Volume (CSV)[6] – The volume within a building or Dwelling Unit serviced by a space heating or cooling system designed to maintain space conditions at 78°F (26°C) for cooling and 68°F (20°C) for heating. The following specific spaces are addressed to ensure consistent application of this definition:
Exception: The wall height used to determine the volume of the volume shall extend from the finished floor to the bottom surface of the floor decking above the subject Dwelling Unit for all floors other than the top floor level. For Dwelling Units on the top floor, this dimension shall extend from the top surface of the finished floor to the interior surface of the enclosure air barrier.
Exception: If the subject Dwelling Unit shares a wall assembly[7] with another Dwelling Unit, then the CSV of the subject Dwelling Unit shall include half the volume of the full width of that shared wall assembly.
Detached Dwelling Unit – A Dwelling Unit that does not meet the definition of Attached Dwelling Unit.
Dwelling – Any building that contains one or two Dwelling Units used, intended, or designed to be built, used, rented, leased, let or hired out to be occupied, or that are occupied for living purposes.
Dwelling Unit – A single unit providing complete, independent living facilities for one or more persons, including permanent provisions for living, sleeping, eating, cooking, and sanitation.
Dwelling Unit Mechanical Ventilation System – A Ventilation system, operating continuously or through a programmed intermittent schedule, consisting of powered Ventilation equipment,[9] related mechanical components,[10] and automated control devices that provides Dwelling Unit Ventilation at a known or measured airflow rate.
Exhaust Ventilation System (Exhaust System) – One or more fans that remove air from the Dwelling Unit, causing outdoor air to enter by Ventilation inlets or normal leakage paths through the Dwelling Unit envelope.
Forced-Air HVAC System – A type of HVAC System that incorporates a Blower Fan to move conditioned air.
Finished Attic – Conditioned Space Volume that is intended for human activities, including but not limited to those for living, sleeping, dining, or cooking as well as toilets, closets, halls, utility areas and above the main Dwelling Unit. For example the upper floor of a ‘Cape Cod’ home shall be considered a Finished attic. The Finished Attic shall be included in the Conditioned Floor Area and Conditioned Space Volume.
HVAC System – Cooling-only, heating-only, or combined cooling-heating equipment, including any supply and/or return distribution systems.
Infiltration Volume[11] – The sum of the Conditioned Space Volume of the subject Dwelling Unit, and plus the Conditioned Space Volume and Unconditioned Space Volume of the following adjacent spaces if included[12] during the airtightness measurement of the enclosure: Attics, crawlspaces and the full depth of their floor assemblies above, basements and the full depth of their floor assemblies above, and adjacent mechanical closets and the full width of their wall assemblies between them and the subject Dwelling Unit
Occupiable Space – A room or enclosed space designed for human occupancy in which individuals congregate for amusement, educational or similar purposes or in which occupants are engaged at labor, and which is equipped with means of egress and light and Ventilation facilities meeting the requirements of this standard.
Residential Building – Includes detached one-family Dwellings and, two-family Dwellings and multiple single-family Dwellings (Townhouses) and Group R-2, R-3, and R-4 buildings three stories or less in height above grade plane.[13]
Shall – As used in this Standard, the word “shall” means that the action specified is mandatory and shall be accomplished by the responsible party.
Sleeping Unit – A room or space in which people sleep, which can also include permanent provisions for living, eating, and either sanitation or kitchen facilities but not both. Such rooms and spaces that are also part of a Dwelling Unit are not Sleeping Units.
Townhouse – A single-family Dwelling Unit constructed in a group of three or more attached units in which each unit extends from the foundation to roof and with open space on at least two sides.
Unconditioned Space Volume[14] – The volume within a building or Dwelling Unit that is not Conditioned Space Volume but which contains heat sources or sinks that influence the temperature of the area or room. The following specific spaces are addressed to ensure consistent application of this definition for inclusion in Unconditioned Space Volume:
Exception: If the volume of one of the spaces horizontally adjacent to a wall assembly is a Dwelling Unit other than the subject Dwelling Unit, then the volume of the full width of that wall assembly shall be evenly divided between both adjacent Dwelling Units.
Unfinished Sealed Attic – An unoccupied Attic that is not vented. This space shall not be included in the Conditioned Floor Area, but may be included in the Conditioned Space Volume (CSV) provided it meets the requirements laid out in the definition of CSV.
Vented Attic – An attic that does not meet the criteria of either a Finished Attic or an Unfinished Sealed Attic and therefore is not included in either the Conditioned Floor Area or Conditioned Space Volume.
Ventilation – The process of supplying outdoor air to or removing indoor air from a Dwelling Unit by natural or mechanical means. Such air may or may not have been conditioned.
Whole-House Fan – A forced air system consisting of a fan or blower that exhausts at least 5 ACH of indoor air to the outdoors, thereby drawing outdoor air into a home through open windows and doors for the purpose of cooling the home.
[1] (Normative Note) Conditioned Space Volume that is intended for human activities, including but not limited to those for living, sleeping, dining, or cooking as well as toilets, closets, halls, utility areas and above the main Dwelling Unit, (for example a ‘Cape Cod’ home), is not considered Attic space and shall be included in the Conditioned Floor Area.
[2] (Informative Note) Informative Annex A contains a table that summarizes parts of a Dwelling Unit that are included in CFA.
[3] (Informative Note) For example, a common or demising wall.
[4] (Informative Note) That is, it does not span multiple Dwelling Units undivided.
[5] (Informative Note) Conditioned Space Volume that is intended for human activities (e.g., for living, sleeping, dining, or cooking; as well as toilets, closets, halls, utility areas, and laundry areas) and above the main Dwelling Unit, such as in a ‘Cape Cod’ home, is not considered Attic space and can be included in the Conditioned Floor Area.
[6] (Informative Note) Informative Annex A has a table that summarizes parts of a Dwelling Unit that are included in Conditioned Space Volume.
[7] (Informative Note) For example, a common or demising wall.
[8] (Informative Note) That is, it does not span multiple Dwelling Units undivided.
[9] (Informative Note) Such as motor-driven fans and blowers.
[10] (Informative Note) Such as ducts, inlets, dampers, or filters.
[11] (Informative Note) Informative Annex A has a table that summarizes parts of a Dwelling Unit that are included in Infiltration Volume.
[12] (Informative Note) Sections 4.2.4, 4.2.5, 4.2.6, and 4.2.7 define whether these adjacent spaces are to be included in Infiltration Volume.
[13] (Normative Note) The definition of Residential Building corresponds to the IECC definition of Residential Building. The Occupancy Groups R-2, R-3 and R-4 are as established by the International Building Code.
[14] (Informative Note) Informative Annex A has a table that summarizes parts of a Dwelling Unit that are included in Unconditioned Space Volume.
Comment #2Page Number: 6Paragraph / Figure / Table / Note: Definition for Infiltration VolumeComment Intent: ObjectionComment Type: TechnicalComment: There is a fundamental problem with the proposed updated definition of Infiltration Volume, involving its impact on Standard 301. Both Std 380 and Std 301 rely on shared definitions, and Infiltration Volume is a critical one. Until now, Infiltration Volume always encompassed the entirety of Conditioned Space Volume (CSV). Because Std 301 implicitly requires that simulations of a home be single-zone models (i.e. controlled by a single thermostat), Std 301 effectively requires that Infiltration Volume include the entirety of CSV. While I understand and applaud the goals of this change in the definition, I believe the current iteration is not viable without further work and collaboration between the sub-committees responsible for Std 301 and Std 380. The collaboration might also need to involve the software vendors and RESNET’s Energy Modeling Director. I do not know how readily any of the Accredited software vendors could transition to a multi-zone ERI simulation, assuming Std 301 was changed to make that possible. Raters and their Builder clients may also find this change problematic. For instance, if a house plan is modeled assuming that all of CSV is in the Infiltration Volume, and then testing at final forces the Infiltration Volume to exclude part of CSV, it is likely to cause a significant change in the HERS Index for that home versus the house plan. ----------------------------- In addition, the current proposed definition makes a vague distinction between "... the Conditioned Space Volume of the subject Dwelling Unit ..." versus "... the Conditioned Space Volume and Unconditioned Space Volume of the following adjacent spaces if included during the airtightness measurement of the enclosure ...". Note that the definition for Conditioned Space Volume does not allow for such a distinction.
There is a fundamental problem with the proposed updated definition of Infiltration Volume, involving its impact on Standard 301.
Both Std 380 and Std 301 rely on shared definitions, and Infiltration Volume is a critical one. Until now, Infiltration Volume always encompassed the entirety of Conditioned Space Volume (CSV). Because Std 301 implicitly requires that simulations of a home be single-zone models (i.e. controlled by a single thermostat), Std 301 effectively requires that Infiltration Volume include the entirety of CSV.
While I understand and applaud the goals of this change in the definition, I believe the current iteration is not viable without further work and collaboration between the sub-committees responsible for Std 301 and Std 380. The collaboration might also need to involve the software vendors and RESNET’s Energy Modeling Director.
I do not know how readily any of the Accredited software vendors could transition to a multi-zone ERI simulation, assuming Std 301 was changed to make that possible.
Raters and their Builder clients may also find this change problematic. For instance, if a house plan is modeled assuming that all of CSV is in the Infiltration Volume, and then testing at final forces the Infiltration Volume to exclude part of CSV, it is likely to cause a significant change in the HERS Index for that home versus the house plan.
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In addition, the current proposed definition makes a vague distinction between "... the Conditioned Space Volume of the subject Dwelling Unit ..." versus "... the Conditioned Space Volume and Unconditioned Space Volume of the following adjacent spaces if included during the airtightness measurement of the enclosure ...". Note that the definition for Conditioned Space Volume does not allow for such a distinction.
Comment #3Page Number: 9Paragraph / Figure / Table / Note: Section 4.2.4.1Comment Intent: Not an ObjectionComment Type: EditorialComment: This section includes an unnecessary distinction for whether sealed (unvented) attics are classified as being in Conditioned Space Volume or Unconditioned Space Volume. For simplicity, the unnecessary content should be struck. Proposed Change: 4.2.4.1. If an Attic is contiguous with and dedicated[1] to the subject Dwelling Unit and is either: a) Conditioned Space Volume or b) Unconditioned Space Volume, unvented, and its roof deck and exterior walls are both insulated and air-sealed; then any exterior Attic access doors, hatches, and vents shall be closed to the extent possible. The pressure difference between the Attic and subject Dwelling Unit shall be evaluated during the airtightness test, per Section 4.4.1.3 (one-point airtightness test) or 4.4.2.3 (multi-point airtightness test), to determine whether to include the Attic in the Infiltration Volume. [1] (Informative Note) That is, it does not span multiple Dwelling Units undivided.
This section includes an unnecessary distinction for whether sealed (unvented) attics are classified as being in Conditioned Space Volume or Unconditioned Space Volume. For simplicity, the unnecessary content should be struck.
4.2.4.1. If an Attic is contiguous with and dedicated[1] to the subject Dwelling Unit and is either: a) Conditioned Space Volume or b) Unconditioned Space Volume, unvented, and its roof deck and exterior walls are both insulated and air-sealed; then any exterior Attic access doors, hatches, and vents shall be closed to the extent possible. The pressure difference between the Attic and subject Dwelling Unit shall be evaluated during the airtightness test, per Section 4.4.1.3 (one-point airtightness test) or 4.4.2.3 (multi-point airtightness test), to determine whether to include the Attic in the Infiltration Volume.
[1] (Informative Note) That is, it does not span multiple Dwelling Units undivided.
Comment #4Page Number: 9-10Paragraph / Figure / Table / Note: Section 4.2.5.1Comment Intent: ObjectionComment Type: TechnicalComment: Conflicting procedural steps in 4.2.5 (Crawlspaces) vs 4.2.8: Although section 4.2.8 requires “All doors between rooms inside the Conditioned Space Volume shall be opened,” section 4.2.5 calls for all doors & hatches between crawlspaces and the rest of the home to be closed. If that crawlspace happens to be within CSV, then section 4.2.5.1 allows such doors & hatches to be opened, but the existing language can be interpreted to only allow that if that conditioned crawlspace also has its exterior walls insulated. Since there are plenty of conditioned crawlspaces that are within CSV but do not have insulated foundation walls, this is a problem. Proposed Change: 4.2.5.1. If a crawlspace is contiguous with and dedicated18 to the subject Dwelling Unit and is either: a) Conditioned Space Volume or b) Unconditioned Space Volume, that is unvented, and its with all exterior walls are both insulated and air-sealed; then any exterior crawlspace access doors, hatches, and vents shall be closed to the extent possible. The pressure difference between the crawlspace and subject Dwelling Unit shall be evaluated during the airtightness test, per Section 4.4.1.3 (one-point airtightness test) or 4.4.2.3 (multi-point airtightness test), to determine whether to include the crawlspace and full depth of its floor assembly above in the Infiltration Volume.
Conflicting procedural steps in 4.2.5 (Crawlspaces) vs 4.2.8:
4.2.5.1. If a crawlspace is contiguous with and dedicated18 to the subject Dwelling Unit and is either: a) Conditioned Space Volume or b) Unconditioned Space Volume, that is unvented, and its with all exterior walls are both insulated and air-sealed; then any exterior crawlspace access doors, hatches, and vents shall be closed to the extent possible. The pressure difference between the crawlspace and subject Dwelling Unit shall be evaluated during the airtightness test, per Section 4.4.1.3 (one-point airtightness test) or 4.4.2.3 (multi-point airtightness test), to determine whether to include the crawlspace and full depth of its floor assembly above in the Infiltration Volume.
Comment #5Page Number: 11Paragraph / Figure / Table / Note: 4.2.6.1Comment Intent: ObjectionComment Type: TechnicalComment: Conflicting procedural steps in 4.2.6 (Basements) vs 4.2.8: Although section 4.2.8 requires “All doors between rooms inside the Conditioned Space Volume shall be opened,” section 4.2.6 calls for all doors between basements and the rest of the home to be closed. If that basement happens to be within CSV, then section 4.2.6.1 allows such doors to be opened, but the existing language can be interpreted to only allow that if that conditioned basement also has its exterior walls insulated. Since there are plenty of conditioned basements that are within CSV but do not have insulated foundation walls, this is a problem. Proposed Change: 4.2.6.1. If a basement is contiguous with and dedicated18 to the subject Dwelling Unit and is either: a) Conditioned Space Volume or b) Unconditioned Space Volume, that is unvented, and its with all exterior walls are both insulated and air-sealed; then any exterior basement access doors, hatches, and vents shall be closed to the extent possible. The pressure difference between the basement and subject Dwelling Unit shall be evaluated during the airtightness test, per Section 4.4.1.3 (one-point airtightness test) or 4.4.2.3 (multi-point airtightness test), to determine whether to include the basement and full depth of its floor assembly above in the Infiltration Volume.
Conflicting procedural steps in 4.2.6 (Basements) vs 4.2.8:
4.2.6.1. If a basement is contiguous with and dedicated18 to the subject Dwelling Unit and is either: a) Conditioned Space Volume or b) Unconditioned Space Volume, that is unvented, and its with all exterior walls are both insulated and air-sealed; then any exterior basement access doors, hatches, and vents shall be closed to the extent possible. The pressure difference between the basement and subject Dwelling Unit shall be evaluated during the airtightness test, per Section 4.4.1.3 (one-point airtightness test) or 4.4.2.3 (multi-point airtightness test), to determine whether to include the basement and full depth of its floor assembly above in the Infiltration Volume.
Comment #6Page Number: 19-20Paragraph / Figure / Table / Note: Section 4.4.1.3Comment Intent: ObjectionComment Type: TechnicalComment: This section indicates that “Additional air-moving fans” are allowed to be used to force an Attic, crawlspace, basement, or adjacent mechanical closet into compliance with the Infiltration Volume criteria. The language here is unclear. I can imagine someone taking this to mean that a Duct Blaster could be installed in the hatch opening between a Sealed Attic and the main space, and operated until the pressure differential with the main space falls either above or below the Infiltration Volume threshold, whichever is preferable for the ERI. In other words, I see this as an opportunity to game the results. Proposed Change: 4.4.1.3. If an Attic, crawlspace, basement, or adjacent mechanical closet is to be evaluated for inclusion in the Infiltration Volume, per Sections 4.2.4.1, 4.2.5.1, 4.2.6.1, 4.2.6.2, or 4.2.7.1, then a manometer shall be used to measure the pressure difference between that space and the subject Dwelling Unit to verify that it is ≤ 10% of the induced enclosure pressure difference measured in Section 4.4.1.2.[1] To achieve this limit, openings between the adjacent space and the subject Dwelling Unit are permitted to be created during this test.[2] Where no direct opening exists between the adjacent space and the subject Dwelling Unit, Aadditional air-moving fans are also permitted to be operated in the exterior openings of the adjacent space to achieve this limit, as long as the same induced enclosure pressure difference as the subject Dwelling Unit is achieved and the airflow of the additional air-moving fans is included in the recorded airflow. [1] (Informative Note) For example, if the induced enclosure pressure difference is 50 Pa, then the pressure differential between the adjacent space and the subject Dwelling Unit must be ≤5 Pa for the space to be included in the Infiltration Volume. [2] (Informative Note) Examples include, but are not limited to, opening doors and hatches between the adjacent space and the subject Dwelling Unit or removing the blower compartment panel of a Forced Air HVAC System in the adjacent space.
This section indicates that “Additional air-moving fans” are allowed to be used to force an Attic, crawlspace, basement, or adjacent mechanical closet into compliance with the Infiltration Volume criteria.
The language here is unclear. I can imagine someone taking this to mean that a Duct Blaster could be installed in the hatch opening between a Sealed Attic and the main space, and operated until the pressure differential with the main space falls either above or below the Infiltration Volume threshold, whichever is preferable for the ERI. In other words, I see this as an opportunity to game the results.
4.4.1.3. If an Attic, crawlspace, basement, or adjacent mechanical closet is to be evaluated for inclusion in the Infiltration Volume, per Sections 4.2.4.1, 4.2.5.1, 4.2.6.1, 4.2.6.2, or 4.2.7.1, then a manometer shall be used to measure the pressure difference between that space and the subject Dwelling Unit to verify that it is ≤ 10% of the induced enclosure pressure difference measured in Section 4.4.1.2.[1] To achieve this limit, openings between the adjacent space and the subject Dwelling Unit are permitted to be created during this test.[2] Where no direct opening exists between the adjacent space and the subject Dwelling Unit, Aadditional air-moving fans are also permitted to be operated in the exterior openings of the adjacent space to achieve this limit, as long as the same induced enclosure pressure difference as the subject Dwelling Unit is achieved and the airflow of the additional air-moving fans is included in the recorded airflow.
[1] (Informative Note) For example, if the induced enclosure pressure difference is 50 Pa, then the pressure differential between the adjacent space and the subject Dwelling Unit must be ≤5 Pa for the space to be included in the Infiltration Volume.
[2] (Informative Note) Examples include, but are not limited to, opening doors and hatches between the adjacent space and the subject Dwelling Unit or removing the blower compartment panel of a Forced Air HVAC System in the adjacent space.
Comment #7Page Number: 7Comment Intent: Not an ObjectionComment Type: TechnicalComment: JUSTIFICATION: Clarity, Consistency, Comprehensiveness, and Improvement of Likelihood of Successful Execution in the Field While Meeting Intent COMMENT ONE: Is the full shared wall assembly modeled,or only up to the CFA boundary? Proposed Change: TEXT REFERENCE TO COMMENT ONE: Exception: If the subject Dwelling Unit shares a wall assembly with another Dwelling Unit, then the CFA of the subject Dwelling Unit shall extend to the midpoint of that shared wall assembly
Comment #8Page Number: 8Comment Intent: Not an ObjectionComment Type: TechnicalComment: JUSTIFICATION: Clarity, Consistency, Comprehensiveness, and Improvement of Likelihood of Successful Execution in the Field While Meeting Intent COMMENT ONE: Essentially the entire volume of an adiabatic floor assembly is modeled? Or is this attempting to refer to a unit with another unit above and cover how to deal with the rim/band area (which we are being directed to model as wall surface?) Proposed Change: TEXT REFERENCE TO COMMENT ONE: Exception: The wall wall height used to determine the volume of the volume shall extend from the finished floor to the bottom surfaceside of the floor decking above the subject Dwelling Unit for all floors other than the topnon-top floor level.
Comment #9Page Number: 11Comment Intent: Not an ObjectionComment Type: TechnicalComment: JUSTIFICATION: Clarity, Consistency, Comprehensiveness, and Improvement of Likelihood of Successful Execution in the Field While Meeting Intent COMMENT ONE: Included as unconditioned? Or included as conditioned? Proposed Change: TEXT REFERENCE TO COMMENT ONE: If either one or both of the volumes above and below a floor assembly is Unconditioned Space Volume, then the volume of the full depth of the floor assembly shall be included.
Comment #10Page Number: 23Comment Intent: ObjectionComment Type: TechnicalComment: JUSTIFICATION: Clarity, Consistency, Comprehensiveness, and Improvement of Likelihood of Successful Execution in the Field While Meeting Intent COMMENT ONE: This is mandatory as a ‘shall’ per 4.2.4.1, which then requires a re-run of the BD to get the ‘correct’ # for a sprayfoamed attic, surely? Seems like 4.4 is written as having attic space open, then test the boundary and close if the 10% delta is not met, but 4.2 is written as everything is closed, then re-run BD if the 10% IS met? Proposed Change: TEXT REFERENCE TO COMMENT ONE: 4.4.1.3. If an Attic, crawlspace, basement, or adjacent mechanical closet is to be evaluated for inclusion in the Infiltration Volume, per Sections 4.2.4.1, 4.2.5.1, 4.2.6.1, 4.2.6.2, or 4.2.7.1, then a manometer shall be used to measure the pressure difference between that space and the subject Dwelling Unit to verify that it is ≤ 10% of the induced enclosure pressure difference measured in Section 4.4.1.2.