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20 August 2013
1
BCA SECTION J CHANGES OVERVIEW
THE BCA: THE GOOD THE BAD & THE UGLY
20 August 2013
MICHAEL SHAW
ESD MANAGER
J1,J2,J3
J5
J6
J7
J8
Refresher
• J1 Insulation and Rooflights
• J2 Glazing and Shading, J3 Building Sealing
• J5 Air-Conditioning & Ventilation
• J6 Artificial Lighting & Power
• J7 Pools & Spas, J8 Metering
20 August 2013
2
Major Changes since 2009
Major Changes since 2009
• Section J major overhaul in BCA2010. Class 2&4 - 6 star
HERS rating, commercial buildings 2:1 benefit/cost ratio.
BCA2013 changes:
• Application of J1, J2 & J3 Building fabric non-conditioned
space exemption clause rewritten
• Fan motor power limits redefined
• Glazing & rooflight clarification: U-value and SGHC are
whole system values
• Application of glazing & rooflight area limits to non-
conditioned “buffer” spaces to allow reduced insulation in
internal envelope wall
20 August 2013
3
R2.2/3.2→
R3.2-4.2
R4.3 → R4.8
R2.7/3.2 → R3.2-4.2
R3.0/3.2 → R3.2-4.2
R3.8/3.2 → R3.7
R3.2 unchanged
}
J1.3 DTS Insulation – Changes 2009-2010+ Roof/Ceiling
J1.3 DTS Insulation – Changes 2009-2010+ Roof/Ceiling
• Table J1.3b introduced to increase ceiling insulation
where there is significant (>0.5%)loss of insulation
20 August 2013
4
R1.4/1.8
→ R3.3
R2.8 → R3.8
R1.4/1.8 → R2.8
R1.7/1.8 → R2.8
R1.9/1.8 → R2.8
R1.7/1.8 → R2.8
}
J1.5 DTS Insulation – Changes 2009-2010+ External Walls
Nil/R1.5
→ R2.0
R2.5 → R3.5
Nil → R2.0
Nil/R1.5 → R2.0
R1.0/1.5 → R2.0
R1.0/1.5 → R2.0
}
J1.6 DTS Insulation – Changes 2009-2010+ Susp. Floors
Worst case exposure (d) from Table 1.6
20 August 2013
5
• BCA2009 allowed <10%, now 5% maximum allowed
• Section J1.4 Rooflight areas for rooflight shaft index<0.5
Rooflight area
as % of floor
area served
<2% 2-3% 3-4% 4-5%
SHGCmax 0.83 0.57 0.43 0.34
U-valuemax 8.5 5.7 4.3 3.4
Example SG clear Low-E clr DG supergreen
J1.4 DTS Rooflights – Changes 2009-2010+
• Control of internal glazing thermal performance in
envelope between conditioned and “buffer” space
• Façade glazing area limits dependent on:
– Climate zone
– Exposure: window orientation and external shading
– U-value and SHGC of glass and frame
– Building type: 1) shopfront, 2) other,
3)accommodation (classes 3 and 9c) AND Internal
– Wall insulation type (option A or B)
J2.4 DTS Glazing stringency between BCA 2009 and 2010+
20 August 2013
6
J2.4 DTS Glazing stringency* between BCA 2009 and 2010+, classes 5-8, 9a & 9b (non-residential)
Zone
*all
ow
ed
gla
zed
are
a in
BC
A2010
as a
perc
en
tag
e o
f B
CA
2009 a
llo
wan
ce
*as an exact percentage of BCA 2009 allowance
J2.4 DTS Glazing stringency* between BCA 2009 and 2010+, classes 3 and 9c (residential accommodation)
Zone
*as an indicative percentage of BCA 2009 allowance
*all
ow
ed
gla
zed
are
a in
BC
A2010
as a
perc
en
tag
e o
f B
CA
2009 a
llo
wan
ce
20 August 2013
7
J3 DTS Building Sealing refresher
• J3.2 Dampers in chimneys & flues solid fuel appliances
• J3.3 Weather-sealed rooflights
• J3.4 Weather-sealed windows and doors (clause J3.4(d)
BCA2010+ requires all entrances to conditioned spaces
>50m2 to have airlock, self-closer or revolving door)
• J3.5 Self-closing dampers for exhaust fans (NEW
habitable rooms in climate zone 5 added in BCA2010+)
• J3.6 Sealing of roof, walls, floors and openings therein
• J3.7 Self closing dampers for evap coolers (NEW
habitable rooms in climate zone 5 added in BCA2010+)
J5.2 DTS Airconditioning & Ventilation Systems BCA2010+
• BCA2013: Fan motor power targets increased by 30% -
New definition includes fan motor losses for all configs
• Reed switches for Class 3 external doors open >1 min
• VSD’s for fans where supply air quantity varies (no PACs)
• Economy cycle threshold lowered from 50-35kWr
o BCA2011+ Eco cycle: frozen food areas of
supermarkets, labs etc exempted, BCA2012+
processes where humidity control needed
20 August 2013
8
J5.2 DTS Airconditioning & Ventilation Systems BCA2010+
• Fan power allowances reduced in 2010 & expressed as
“fan power” the power delivered to a fan
• Fresh air (Part F4) oversupply limit reduced from 50-20%
• Energy reclaim or modulation extended to all other
building classes (not just 9b) with density <1 person/m2
• Maximum fan power to air flow rate ratio reduced by
10% for mech (not A/C) ventilation systems
• BCA2012+: Elec Substation exemptions
J5.4 DTS Heating & Cooling BCA2010+
• Variable speed pump threshold reduced to 3kW pumps
• Maximum pump power targets altered - expressed
separately for chilled, condenser and heating water
• Slight changes to min efficiencies for water heaters
• Direct electric heating prohibited in most cases
• Condenser fan power clauses (e) to (h) simplified
20 August 2013
9
J6 DTS Artificial Lighting & Power BCA2010+
• J6.2 Illumination Power Density target for class 2&4
• Minor changes to Maximum Illumination Power Density
• Formula for room aspect adjustment factor changed
• Table J6.2b adjustment factors for control devices
added: timer for corridor lighting (0.7 adj factor)
• J6.3 (c)(ii) switching zone max size: function-related
refinement to exempt single functional use spaces
J7 DTS Hot Water Supply BCA2010+
• J7.3 swimming pool heating & pumping added
• J7.4 spa pool heating & pumping added
• Water heating fuel must not be electric resistance
• Cover, time switch for water heater & pump
20 August 2013
10
J8 DTS Access for Maintenance & Monitoring BCA2010+
• Exempt: Class 2 > 2,500m2 and common areas < 500m2
• Gas and/or elec: building or SOU’s > 500m2
• Building > 2,500m2
o A/C plant, heating, cooling, air handling
o Artificial lighting
o Appliance power
o Central hot water supply
o Lifts, escalators, travelators
o Other ancillary plant
OR Alternative Solutions permitted
• JV3 modelling comparison to DTS Reference Building
• Glazing/shading requirements too restrictive
(e.g. clear glazed retail shopfronts)
• Larger rooflights preferred
• Green star projects (e.g. IEQ increased fresh air rates)
• Energy efficient design solutions to multi-res commercial
buildings (3 and 9c)