All the way with Section J Glazing CPD answers Michael Shaw, June 2011

Conditioned space & Envelope Group exercise (p8) Your task: 1. a) define “building envelope” for the purposes of BCA Section J Answer: The parts of a building’s fabric that separate a conditioned space or habitable room from—fabricconditioned space habitable room (a) the exterior of the building; or (b)a non- conditioned space including—conditioned space (i) the floor of a rooftop plant room, lift-machine room or the like; and (ii) the floor above a carpark or warehouse; and (iii) the common wall with a carpark, warehouse or the like.carparkcommon wallcarpark Pp4-6

Conditioned space & Envelope Group exercise (p8) Your task: 1.b) highlight the envelope for this building on north elevation, plan and section Note: attendees at earlier seminar dates will have a similar design in their handouts pp4-6

Thermal envelope - Answer

Assessment activity - section Thermal envelope - Answer

Glazing calculator Group exercise Your task: 1.c) Define the level 1 north facing façade area in elevation and enter the relevant information into the glazing calculator Hint: privacy screens between balconies are full height walls and act to provide same or better shading than extending the horizontal slab overhang by distance P beyond window edge.

North façade – enter into glazing calculator

WWR north = 40% Façade area excludes assumed 200mm thickness of floorslab Note: Clear 6mm single glazing with an unbroken aluminium frame has been assumed as window type to complete the glazing calculator assessment

Glazing calculator Group exercise Your task: 2. Interpret the climate zone 1 glazing charts from EDG Note 66 and give an indicative glazing type that will achieve DTS compliance on the north façade without altering the shading overhang (balcony) or window size. Answer: overhang P/H~0.4, choose U=2.7. SHGC=0.30 gives WWR=35%, To maintain WWR of 40%, SHGC will be <0.30 Indicative glass type – Double glazed low-E with very dark tint

Glazing design for climate zone 1 Double glazing low-E

Glazing calculator Group exercise Your task: 3. a) Using the glazing design charts and any prior experience you have of the glazing calculator, sketch or suggest two ways that DTS compliance could be met by altering the geometry of the design and adopting glazing with a SHGC of 0.5 which will have much better visible light transmission properties. Some possible answers: Reduce area of glazing to the north façade Introduce motorised shading device to extend shading overhang when required (or simply widen the balcony above) Note: both of these answers can impact on daylighting in the space

Performance-based solution Group exercise Your task: 3. b) Assuming that you have been quoted $8,000 for JV3 and two weeks modelling time, how would you justify to this nation-wide client that a JV3 performance-based solution will deliver a better design and documentation outcome? Answer: DTS solutions will not achieve the daylight requirements in the brief, nor allow good design for the accommodation buildings (class 3) DTS solutions are different for different climate zones. Finding a JV3 solution that performs better than DTS in the harsh climate zone 1 is likely to achieve compliance in milder climates, 5 and 7 (standardising documentation and construction)

Performance-based solution Group exercise Your task: 3. c) Outline your ideas on the steps required in a design process to achieve a stress-free JV3 alternative solution Answer: Develop design ideas with an understanding of passive design principles and the glazing limitations imposed by the DTS requirements on each façade orientation Where major façade orientations are not using their full glazing area allowances, talk to a JV3 energy modeller about the possibilities of strategically exceeding the DTS requirements on key orientations Once design is largely complete, conduct preliminary modelling and only then apply for development approval