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Building Take-off

Intent of use


EE4 uses a compliance checking approach to building energy simulation and was not intended to be a design tool. EE4 evaluates building designs strictly according to the Model National Energy Code for Buildings (MNECB) 1997 and "Performance Compliance for Buildings" (MNECB/CS, NRC 1999). On that basis, EE4 incorporates assumptions concerning: air infiltration; supply and exhaust fan operation; occupant densities; schedules of operation; heating and cooling equipment load/part load performance; heat flows and gains; and below grade heat losses; that respond to the specific concerns of the MNECB. There is no Code requirement for EE4 to account for common building automation strategies such as: optimal start/stop; peak load shaving; carbon dioxide ventilation control; internal temperature resets; and equipment interlock strategies.

Guidelines for Building Take-off

Additional modelling rules and simplifying assumptions (addressing some of the control strategies listed above) were developed for use as part of Natural Resources Canada’s (NRCan’s) validation of new building designs compliance requirements. Written explanations describing your inputs and omissions from the simulation are essential to performing the review, and must be provided.
Submitted simulations must incorporate the following guidelines:

  1. Building must be zoned according to the modelling rules outlined in the EE4 Modelling Guide.  Explanations of the zoning strategies (orientation, systems, heating zones versus heating and cooling zones, etc.) must be provided in addition to a zoning diagram;
  2. Simulation must represent all assemblies exposed to ambient conditions, including below grade walls and slabs, and slabs on grade;
  3. Building spaces identified in the simulation should include specific assembly characteristics from the drawings such as walls, roofs, doors, overhanging floors, windows, lighting, below grade areas. These should be summarized in an area-specific spreadsheet outlining lengths, widths and heights of assemblies for verification;
  4. Window overhang geometry must be included when present in the design documents;
  5. Envelope assemblies must be entered in a layer by layer format unless a written explanation is provided as to why this was not possible;
  6. All spaces within the heated envelope (building shell) must be accounted for -- including basements, stairwells, mechanical/electrical/service rooms, corridors, loading docks, storage areas (see MNECB definition "Floor surface area"). Attached unheated spaces such as parking garages, service areas, garbage/recycling enclosures may be omitted provided that the common assemblies (floors, walls, and roofs) are described in the simulation as partitions;
  7. Process equipment (e.g. cooled display cases) can be omitted provided that they contain their own heating, cooling and ventilation system and do not utilize the building systems for these purposes.
  8. Construction documents (drawings and specifications, and/or shop drawings) must be submitted for verification of the simulation. Manufacturer's literature or test data supporting whole window U-values and Solar Heat Gain Coefficients must be submitted. Manufacturer's specifications for equipment (examples: chillers, air-handling systems, heat recovery ventilators, pumps, cooling towers, etc.) must also be provided;
  9. Where window data is not available, entered windows must utilize the ASHRAE Fundamentals Handbook default window u-values and solar heat gain coefficients, or provide a detailed FRAMEplus on-line or LBL Windows 4.1  output.
  10. Written explanations for deviations from the MNECB schedules, occupant densities, minimum outdoor air supply rates, or any EE4 default value, must be provided.
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