A. Intent:
1. The requirements of this Code shall regulate the design of residential envelopes which will provide optimal thermal resistance and minimal air infiltration for the effective utilization of energy regardless of the source of that energy (See definition of "residential buildings").
2. Alternate materials - method of construction, design or insulating systems: the provisions of this Code are not intended to prevent the use of any material, method of construction, design, or insulating system not specifically prescribed herein, provided that such construction, design, or insulating systems meet the intent of the Code. Nor is this Code intended to abridge any safety or health requirements.
3. Determination of the design thermal properties of building components, including insulating materials, shall be based upon the values assigned to the materials in the most recent publication of the Handbook of Fundamentals by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE).
4. This Code sets forth criteria for:
a. New residential buildings (type A-1).
b. Additions to existing residential buildings (type A-1).
B. Exempt Buildings: Buildings that are neither heated or cooled.
C. Application To Existing Buildings:
1. Habitable room additions to existing residential buildings may be made without making the entire building or structure comply. The new work shall conform to the applicable provisions of this Code.
2. Any change in the use of a building that was constructed under this Code shall not be permitted unless such building or structure is in compliance with the applicable requirements of this Code as determined by the new use.
D. Definitions:
BUILDING ENVELOPE: The elements of a building which enclose conditioned spaces through which thermal energy may be transferred to or from the exterior.
BUILDING OFFICIAL: The official authorized to act in behalf of the responsible government agency for the enforcement of this Code.
CONDITIONED FLOOR AREA: The horizontal projection of that portion of interior space which is contained within exterior walls and which is conditioned directly or indirectly by an energy-using system.
ENERGY: The capacity for doing work; taking a number of forms which may be transformed from one into another such as thermal (heat), mechanical (work), electrical, and chemical; in U.S. customary units, measured in kilowatt-hours (kwh) or British thermal units (Btu).
ENERGY, NEW: See definition of New Energy.
ENERGY, RECOVERED: See definition of Recovered Energy.
EXTERIOR ENVELOPE: See definition of Building Envelope.
FUEL: A substance which may be used to give heat or generate electricity.
GRADE: The average of the finished ground level at the center of the walls of a building. In case building walls are parallel to and within five feet (5') of a sidewalk(s), the grade shall be the average finished elevation of such sidewalk(s) between side lot lines.
GROSS FLOOR AREA: The sum of areas of the several floors of the building, including basements, cellars, mezzanine and intermediate floored tiers and penthouse of headroom height, measured from the exterior faces of exterior walls or from the centerline of walls separating buildings.
GROSS WALL AREA: The vertical projection of the exterior wall area bounding interior space which is conditioned by an energy-using system; includes opaque wall, window and door areas. The gross area of exterior walls consists of all opaque wall areas, including foundation walls above grade, between floor spandrels, peripheral edges of floors, and window areas including sash, and door areas, where such surfaces are exposed to outdoor air and enclose a heated or mechanically cooled space including interstitial areas between two (2) such spaces.
HVAC: Heating, ventilating and air conditioning.
HABITABLE ROOM ADDITION: Any room or enclosed floor space used or intended to be used for living purposes by human occupants including but not limited to bathrooms, furnace rooms, laundry rooms and enclosed communicating corridors.
HEAT: The form of energy that is transferred by virtue of a temperature difference.
HEATED SPACE: Space, within a building, which is provided with a positive heat supply system.
HISTORIC BUILDINGS: Buildings which have been specifically designated as historically significant by the State or local governing body, or listed in The National Register of Historic Places, or which have been determined to be eligible for listing.
INFILTRATION: The uncontrolled inward air leakage through cracks and interstices in any building element and around windows and doors of a building, caused by the pressure effects of wind and/or the effect of differences in the indoor and outdoor air density.
MOBILE HOME: Any vehicle or similar portable structure used or so constructed as to permit its being conveyed upon the public streets or highways and designed to permit the occupancy thereof as a dwelling unit for one or more persons, provided that any structure in whole on a permanent foundation, with wheels, tongue and hitch permanently removed, shall not be construed as a mobile home.
NEW ENERGY: Energy, other than recovered energy, utilized for the purpose of heating or cooling.
NONDEPLETABLE ENERGY SOURCES: Sources of energy (excluding minerals) derived from incoming solar radiation including photosynthetic processes; from phenomena resulting therefrom including wind, waves and tides, lake or pond thermal differences; and energy derived from the internal heat of the earth, including nocturnal thermal exchanges.
OPAQUE AREAS: All exposed areas of a building envelope which enclose conditioned space, except openings for windows, skylights, doors and building service systems.
R: The thermal resistance of a -
material, or a building (R-1).
envelope section. u
RECOVERED ENERGY: Energy utilized which would otherwise be wasted from an energy system.
REHEAT: The application of sensible heat to supply air that has been previously cooled below the temperature of the conditioned space by either mechanical refrigeration or the introduction of outdoor air to provide cooling.
RESET: Adjustment of the set point of a control instrument to a higher or lower value automatically or manually to conserve energy.
RESIDENTIAL BUILDING TYPE A-1: All dwelling units including multi-family buildings not exceeding thirty five feet (35') in height. Mobile Homes are excluded from this definition.
ROOF ASSEMBLY: A. A roof assembly shall be considered as all components of the roof/ceiling envelope through which heat flows, thereby creating a building transmission heat loss or gain, where such assembly is exposed to outdoor air and encloses a heated or mechanically cooled space.
B. A gross area of a roof assembly consists of the total interior surface of such assembly, including skylights exposed to the heated or mechanically cooled space.
C. When return air ceiling plenums are employed, the roof/ceiling assembly shall:
1. For thermal transmittance purposes, not include the ceiling proper nor the plenum space as part of the assembly and,
2. For gross area purposes, be based upon the interior face of the upper plenum surface.
SERVICE SYSTEMS: All energy-using systems in a building that are operated to provide services for the occupants or processes housed therein, including but not limited to HVAC, service water heating, illumination, transportation, cooking or food preparation, laundering or similar functions.
SERVICE WATER HEATING: Supply of hot water for domestic or commercial purposes other than comfort heating.
SERVICE WATER HEATING DEMAND: The maximum design rate of energy withdrawal from a service water heating system in a designated period of time (usually an hour a day).
SOLAR ENERGY SOURCE: Source of thermal, chemical or electrical energy derived directly from conversion of incident solar radiation.
THERMAL TRANSMITTANCE (U): Overall coefficient of heat transmission (air to air) expressed in units of Btu per hour per square foot per degree Fahrenheit. It is the time rate of heat flow. The U value applies to combinations of different materials used in series along the heat flow path, single materials that comprise a building section, cavity air spaces, and surface air films on both sides of building element (U-1/R).
THERMAL TRANSMITTANCE (Uo): Overall (weighted average) heat transmission of a gross area of the exterior building envelope, expressed in units of Btu per hour per square foot of floor area per degree Fahrenheit.
THERMOSTAT: An instrument which measures changes in temperature and controls equipment for maintaining a desired temperature.
E. Plans And Specifications: Plans and Specifications shall be submitted with each application for a building permit.
1. The plans and specifications shall show in sufficient detail all pertinent data and features of the building including design criteria, exterior and interior envelope component materials, R-values of the envelope elements, and R-values of the insulating materials to indicate conformance with the requirements of this Code.
2. Buildings designed with a value of overall thermal transmittance (Uo) equal to or smaller than one resulting from the R-value requirements presented herein shall be considered to meet the Code requirements.
F. Building Classification For Purpose Of This Code: Same as residential definition (Type A-1). All dwelling units including multi-family buildings not exceeding thirty five feet (35') in height.
G. Building Design By Acceptable Practice For Residential Buildings (Type A-1): Requirements contained in this Section are applicable to only Type A-1 buildings. Such buildings, when constructed in accordance with this Section, are deemed to comply with this Code.
1. Opaque Exterior Wall Assemblies: Opaque exterior wall assemblies shall have a combined minimum R-value of nineteen (19), except when the overall heat transmission of the gross area of the exterior building envelope is designed and constructed such that the overall transmittance (U9) is equal to or small than one resulting from the other prescriptive R-value requirements of this Code. (See subsection E2 of this Section)
2. Walls:
a. The exterior wall envelope may be selected from but not limited to the types illustrated in subsection J, Table No. 1 of this Section. Depending on the kind of insulation, the R-value of that insulation and the type of glazing, the maximum permissible percentage of exterior wall to be glazed shall be determined from the glazing chart in subsection J, Table No. 2 of this Section.
b. The exterior wall area shall be calculated using:
(1) The horizontal distance of the perimeter of the exterior wall separating heated from unheated spaces.
(2) The vertical dimension shall be the distance from the finish ceiling of the roof/ceiling assembly to:
(A) The finish floor over an unheated area or
(B) Grade if the interior space is heated below or at that level. Uninsulated foundation walls shall not be included in wall area.
3. Glazing Area: The glazing area shall:
a. Be calculated at the finish opening area.
b. Include all exterior doors.
c. Be unlimited if installed in a south facing wall provided:
(1) The glazing is dual or triple and
(2) The glazing is protected from summer sun intrusion with an opaque overhand protruding a minimum of thirty inches (30") including guttering or one-third (1/3) the overhead to sill distance, whichever is greater, or other appropriate shading is provided (south is defined as falling in a cone limited +30 degrees from true solar south).
4. Roof/Ceiling: The roof/ceiling assembly shall have a combined minimum value of R-30 except under the condition of subsection E2 of this Section. See typical roof/ceiling assemblies, subsection J3, Table No. 3 of this Section.
5. Floors Over Unheated Spaces: The floor assemblies shall be insulated with minimum R-19, except under the condition of subsection E2 of this Section.
6. Foundation Walls: Foundation walls in heated basements shall be insulated with a minimum of R-10 from underside of floor to two feet (2') below grade (see "grade" definition) on either the exterior or interior of the foundation wall, except under the condition of subsection E2 of this Section.
7. Slab On Ground Floor: Slab on ground floor shall be thermally insulated under for a distance of two feet (2') from the slab edge and down from the top of the slab to the bottom of the slab or two feet (2') from the top of the slab to a depth two feet (2') below grade along its perimeter with a proven and accepted thermal insulation having a total R-value of ten (10) or better.
8. Air Leakage: All openings or penetrations shall be caulked, gasketed, or weatherstripped including exterior joints around windows and door frames; openings between walls and foundations, between walls and roof/ceilings and between wall panels; openings at penetrations of utility services through walls, floors, and doors; and all other such openings.
9. Exterior Doors And Windows: All exterior doors and windows shall be designed to minimize air leakage into or from the building envelope.
10. Foundations: Foundations shall have a sill sealer between the sill plate and supporting foundation wall.
11. Aluminum Windows: All aluminum windows shall have a thermal break between the interior and exterior walls.
H. Service Water Heating For Type A-1 Buildings:
1. Heat Efficient Method: Hot water for domestic, sanitary and swimming pool purposes shall be generated and delivered in a manner conducive to saving heat energy.
2. Pipe Wrap: It is recommended that service hot water pipes be installed with a commercially available pipe wrap.
3. Temperature Controls:
a. Automatic: Service water heating systems shall be equipped with automatic temperature controls.
b. Shut Down: A separate switch shall be provided to permit turning off energy supplied to electric service water heating systems. A separate valve shall be provided to permit turning off the energy supplied to the main burner(s) of all other types of service water heating systems.
I. Building Mechanical Equipment And Control For Residential Buildings (Type A-1):
1. All HVAC devices, components and their elements shall conform to the requirements of this Section.
2. Combustion Heating Equipment: All gas and oil fired comfort heating equipment shall show a minimum combustion efficiency of seventy five percent (75%) at maximum rated output. Combustion efficiency is defined at one hundred percent (100%) minus stack losses in percent of heat input. Stack losses are:
a. Loss due to sensible heat in dry flue gas.
b. Loss due to incomplete combustion.
c. Loss due to sensible and latent heat in moisture formed by combustion of hydrogen in the flue.
3. Control:
a. Temperature: Each HVAC system shall be provided with at least one thermostat for the regulation of temperature. It is recommended that each thermostat be set as follows:
(1) Where used to control heating, a maximum temperature of seventy two degrees Fahrenheit (72°F).
(2) Where used to control cooling, a minimum temperature of seventy six degrees Fahrenheit (76°F).
4. Thermostats: At least one thermostat for regulation of space temperature shall be provided for each separate HVAC system and/or for each dwelling unit.
5. Duct Insulation: All ducts, plenums and enclosures not installed within the heated space by thermally insulated with a minimum of R-6 and shall have all transverse joints sealed with tape or mastic.
6. Dampers: It is recommended that fireplaces have operable dampers and utilize outside combustion air. (Ord. 80-118; 1998 Code)