NCC 2022 Volume One - Building Code of Australia Class 2 to 9 buildings


Specification 34 Modelling parameters for J1V3

Specification 34 Modelling parameters for J1V3

This Specification contains the required modelling parameters for J1V3.

The annual greenhouse gas emissions must be calculated for the reference building in accordance with the following:

  1. The reference building must—
    1. comply with Deemed-to-Satisfy Provisions in Parts J4 to J8; and
    2. have the minimum amount of mechanical ventilation required by Part F6.
  2. The external walls must have a solar absorptance of 0.6.
  3. The air-conditioning must—
    1. for 98% of the annual hours of operation, achieve temperatures between—
      1. 18°CDB to 25°CDB for conditioned spaces with transitory occupancy; and
      2. subject to (ii), 21°CDB to 24°CDB in all other conditioned spaces; and
    2. if the proposed building has no mechanically provided cooling or has mixed mode cooling, have the same method of control and control set points for non-mechanical cooling as the proposed building.
  4. The infiltration rate in each zone must be—
    1. 0.7 air changes per hour throughout all zones when there is no mechanically supplied outdoor air; and
    2. 0.35 air changes per hour throughout all zones at all other times.
  5. The artificial lighting must achieve the required maximum illumination power density in Part J7 without applying the control device adjustment factors.
  6. Minimum Energy Performance Standards must be applied to services not covered by Parts J6 to J8.

(1) The annual greenhouse gas emissions must be calculated for the proposed building and the reference building using the same—

  1. annual greenhouse gas emissions calculation method; and
  2. greenhouse gas emissions factors in accordance with (2); and
  3. location in accordance with (3); and
  4. adjacent structures and features; and
  5. orientation; and
  6. building form in accordance with (4); and
  7. testing standards including for insulation, glazing, water heater and unitary air-conditioning equipment; and
  8. fabric and glazing in accordance with (5); and
  9. services in accordance with (6) and S34C4.

(2) For the purposes of (1)(b), greenhouse gas emissions factors must be based on either—

  1. the factors in Table S34C3; or
  2. the current full fuel cycle emissions factors published by the Australian Government, except, where the greenhouse gas intensity of electricity is less than half the greenhouse gas intensity of natural gas—
    1. electricity is to be weighted as 1; and
    2. natural gas is to be weighted as 2.

(3) For the purposes of (1)(c), location must be either—

  1. location where the building is to be constructed if appropriate climatic data is available; or
  2. the nearest location with similar climatic conditions, for which climatic data is available.

(4) For the purposes of (1)(f), building form must include—

  1. the roof geometry; and
  2. the floor plan; and
  3. the number of storeys; and
  4. the location, extent and configuration of ground floors and basements; and
  5. the size and location of glazing; and
  6. external doors.

(5) For the purposes of (1)(h), fabric and glazing must include—

  1. quality of insulation installation; and
  2. thermal resistance of air films including any adjustment factors, moisture content of materials and the like; and
  3. dimensions of external, internal and separating walls; and
  4. internal shading devices, their colour and their criteria for operation.

(6) For the purposes of (1)(i), services must include—

  1. range and type of services and energy sources, other than renewable energy generated on site; and
  2. assumptions and means of calculating the temperature difference across air-conditioning zone boundaries; and
  3. floor coverings and furniture and fittings density; and
  4. internal artificial lighting illumination levels; and
  5. internal heat gains including people, lighting, appliances, meals and other electric power loads; and
  6. air-conditioning, including chiller, fan and boiler equipment, system configuration and zones; and
  7. profiles for occupancy, air-conditioning, lighting and internal heat gains from people, hot meals, appliances, equipment and heated water supply systems based on—
    1. Specification 35; or
    2. NABERS Energy simulation requirements; or
    3. Green Star simulation requirements; or
    4. the actual building if—
      1. the operating hours per year are not less than 2 500; or
      2. the daily operating profiles are not listed in Specification 35; and
  8. supply heated water temperature and rate of use; and
  9. infiltration values, subject to (7); and
  10. sequencing for water heaters, refrigeration chillers and heat rejection equipment such as cooling towers; and
  11. representation of clothing and metabolic rate of the occupants; and
  12. control of air-conditioning except—
    1. the reference building must have variable temperature control for chilled and heated water that modulates the chilled water and heated water temperatures as required to maximise the efficiency of the chiller or boiler operation during periods of low load; and
    2. if the controls for the proposed building are not adequately specified or cannot be simulated, the sample control specifications in Appendix B of AIRAH-DA28 must be used; and
  13. environmental conditions such as ground reflectivity, sky and ground form factors, temperature of external bounding surfaces, air velocities across external surfaces and the like; and
  14. number, sizes, floors and traffic served by lifts and escalators.

(7) For the purposes of (6)(i), the intended building leakage at 50 Pa may be converted into a whole building infiltration value for the proposed building infiltration using Tables 4.16 to 4.24 of CIBSE Guide A if all of the following have been specified:

  1. Additional sealing provisions to those required by Part J5.
  2. An intended building leakage of less than 10 m3/hr.m2 at 50 Pa.
  3. Pressure testing to verify achievement of the intended building leakage.
Table S34C3 Greenhouse gas emissions factors (kgCO2-e/GJ)
Electricity - 236 162 254 101 44 279 191
Gas - 51.53 51.53 51.53 51.53 51.53 51.53 51.53
Table Notes
  1. National emissions factors are not applicable to calculations for buildings in the ACT as they do not take into account investments in renewable electricity generation in the national electricity market made by the ACT.
  2. Values for the ACT can be found in the ACT Appendix.

For the modelling of services for the purposes of calculating annual greenhouse gas emissions

  1. system demand and response for all items of plant must be calculated on a not less frequent than hourly basis; and
  2. energy usage of all items of plant must be calculated with allowances for—
    1. part load performance; and
    2. staging to meet system demand; and
  3. energy usage of cooling plant must be calculated with allowances for—
    1. the impact of chilled water temperature on chiller efficiency; and
    2. the impact of condenser water temperature on water-cooled plant efficiency; and
    3. the impact of ambient temperature on air-cooled plant efficiency; and
    4. the energy use of primary pumps serving individual chillers; and
    5. the energy use of auxiliary equipment, including controls and oil heating for chillers; and
    6. thermal losses in the chilled water system; and
    7. the impact of chilled water temperature on thermal losses in the chilled water system; and
  4. energy usage of water heating systems for space heating must be calculated with allowances for—
    1. the impact of water temperature on water heater efficiency; and
    2. the energy use of primary or feedwater pumps serving individual water heaters; and
    3. thermal losses in water heating systems; and
    4. the thermal mass of water heating systems, accounting for thermal losses during periods when the system is not operating; and
  5. energy usage of fan and pump systems must be calculated with allowances for—
    1. the method of capacity regulation; and
    2. the use of either fixed or variable pressure control; and
  6. energy usage of pump systems must be calculated with allowances for the system fixed static pressure head; and
  7. energy usage of auxiliary equipment associated with co-generation and tri-generation systems, including pumps, cooling towers and jacket heaters, must be calculated; and
  8. where the energy usage of the heated water supply for food preparation and sanitary purposes or the energy usage of lifts and escalators is the same in the proposed building and the reference building, they may be omitted from the calculation of both the proposed building and the reference building; and
  9. energy use of a lift in a building with more than one classification may be apportioned according to the number of storeys of the part for which the annual greenhouse gas emissions and thermal comfort level are being calculated.