gbi pro series walls and roofs - mgbc.org.my › downloads › 20150123-workshop-on... · gbi pro...
Post on 31-May-2020
9 Views
Preview:
TRANSCRIPT
GBI PRO SERIES
PASSIVE DESIGN Passive design strategy
to orientate,
to shade,
to insulate,
to ventilate and
to daylit buildings.
Building
Envelope
GBI PRO SERIES
Assumptions
The concept of OTTV is based on the assumption that the envelope of the building is completely enclosed.
In the OTTV formulation, the following items are not considered:
1. internal shading devices eg curtains
2. solar reflection or shading from adjacent buildings 3. green walls
CONCEPT OF OTTV
GBI PRO SERIES
THERMAL RESISTANCE Relationships between thermal conductivity, thermal resistance and U-value
1 R
U =
Material thickness
k R =
Thermal conductivity k =
GBI PRO SERIES
SC) x WWR x CF x(194 U(WWR)6UWWR)(1α15OTTVi fw
MS1525:2007 Clause 5.2.2 says
+
Heat
Conduction
through
Windows
+
Solar Heat
Gain
through
Windows
Heat
Conduction
through
Walls
OTTV =
The formula for the OTTV of any given wall orientation is as follows:
0.2% to 5% 10% to 20% 70% to 85%
CONCEPT OF OTTV
GBI PRO SERIES
15 (1-WWR) Uw where = Solar Absorption = Colour of walls and WWR = Window-to-Wall Ratio and Uw = U-value of the wall 15 x x Wall area ratio x U-value of Wall
Heat Conduction through Walls
GBI PRO SERIES
Black glass 0.99
Red brick, dark brown paint 0.88
Asphalt pavement 0.82
Bare uncoloured concrete 0.65
Green paint 0.47
White semi-gloss paint 0.25
Silver paint 0.25
Polished aluminium sheet 0.12
Absorptivity, for Wall and Roof Surfaces Heat Conduction through Walls
GBI PRO SERIES
External walls
Aircond
zone
Non aircond
zone
Plan View
External walls
Aircond
zone
Non aircond
zone
OTTV
X
GBI PRO SERIES
Plan View
External walls
Aircond zone
Aircond zone
Core
External walls
Aircond zone
Aircond zone
X Core
OTTV
GBI PRO SERIES
External walls
Aircond zone
Aircond zone
Core
External walls
Aircond zone
Aircond zone
Core
Plan View X
OTTV
GBI PRO SERIES
OTTV
applies to
external
walls only Highrise
aircond zone
Lowrise aircond
zone
M&E
Plantroom
X
OTTV
GBI PRO SERIES
Highrise
aircond zone
Lowrise non- aircond
zone
M&E
Plantroom
OTTV applies to external
walls of aircond spaces only
OTTV
GBI PRO SERIES OTTV
Different types of finishes
to external walls
W1 : curtain wall type 1
W2 : curtain wall type 2
W3 : curtain wall type 3
W4 : brick wall, aluminium
cladding
W5 : RC wall, plastered and
painted
W6 : curtain wall type 4
W7 : shopfront glazing
W1 W2 W3
W4
W5
W7
W6
GBI PRO SERIES OTTV
Wall Area WWR Uw SC 1 SC 2 Uf
W1 365 0.45 0.15 0.8 0.32 0.79 3.8
W2 1,400 0.45 0.15 0.8 0.32 1 3.8
W3 895 0.45 0.15 0.8 0.32 0.86 3.8
W4 635 0.31 0.50 3.3 0.28 0.79 5.5
W5 480 0.25 0.75 3.3 0.55 1 6.7
W6 50 0.75 0.15 0.8 0.45 0.6 5.2
W7 180 0.55 0.25 0.8 0.56 0.6 5.2
Total 4,005
W1 W2 W3
W4
W5
W7
W6 West Elevation
GBI PRO SERIES
0.6 Heavy
(Above 50 kg/m²)
0.4 Light
(Under 50 kg/m²)
Maximum U-Value (W/m²K) Roof Weight
Group
MS1525:2007 Clause 5.5.1 Table 9. Maximum U-value for roof (W/m²K)
Roof U-values
GBI PRO SERIES
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0 50 100 150 200 250 300 350
Insulation to lightweight roof
RO
OF
U-V
AL
UE
(W
/m2K
)
INSULATION THICKNESS (mm)
MS 1525 lightweight roof
< 0.4 W/m2K
Roof U-values
GBI PRO SERIES
0.0
0.5
1.0
1.5
2.0
2.5
3.0
0 50 100 150 200 250 300 350
INSULATION THICKNESS (mm)
RO
OF
U-V
AL
UE
(W
/m2K
)
MS 1525 heavyweight roof
< 0.6 W/m2K
Roof U-values Insulation to heavyweight roof
GBI PRO SERIES
– Polystyrene Foam
– mass, thickness and thermal resistance slow down heat transfer
– Mineral Wool (Rock wool)
– reflect radiant heat
– high thermal emissivity
Common roof insulation materials
Roof U-values
GBI PRO SERIES
Clause 5.6.1 The concept of RTTV applies if the roof is provided
with skylight, and the entire enclosure below is fully air-conditioned.
Clause 5.6.2
The maximum recommended RTTV is 25 W/m2.
RTTV MS1525:2007 Clause 5.6
GBI PRO SERIES
Difference in concept between Roof U-value and UHI
Roof U-value measures heat conducted through the roof construction AND
Applies where habitable or living spaces are found directly below it. Habitable spaces below roof need not be fully enclosed or aircond,
and includes pool decks, outdoor dining etc
UHI is about reflecting away solar radiation to achieve a cooler micro-climate.
Once heat comes in, it takes a lot of energy to get it out,
regardless whether the spaces below are occupied or not. OTTV vs ETTV
Roof U-values and UHI
GBI PRO SERIES
Difference in concept between Roof U-value and UHI
Can secondary roofs eg horizontal pergolas or screens be used to calculate Roof U-value?
No, because they can only provide shade but are not a part of the roof construction.
But they can be used to be a part of the calculation to reduce
UHI, ie SM12A of NRNC.
Roof U-values and UHI
GBI PRO SERIES
Secondary Roofs
Roof U-values and UHI
Secondary Roof Over
y Primary Roof
Habitable space
Section
Roof U-value applies here
SRI (UHI) applies here
GBI PRO SERIES
What are vertical planting?
Includes perimeter planting at edges of carparks
Can vertical planting outside building façade score? No, as mentioned in Innovation (FAQ11.1), vertical
planting must be part of the building facade. But will contribute towards greenscape areas under
SM4B NRNC or SM11 RNC
How to calculate OTTV if there exists double volume void decks or roof gardens? Show plan and perspective
Vertical Planting
GBI PRO SERIES
Can PV be used in calculating roof hardscape or Roof U-value?
Similar to pergolas. If PV is constructed as a feature above landscaped area, it
does not count. Same with PV on wall surfaces.
It will count only if it is BIPV, ie it forms part of the roof construction.
What is the SRI of PV surfaces?
SRI is about 40%
New technologies create PV with less SRI.
GBI PRO SERIES
Can insulation below rc slab be a part of Roof U-value? No, because the heat is already in contact with the
structure, and it will spread out into other structures. Hence, it is better to be placed above the structure.
But in renovation works, insulation below rc slab in ceiling space can be considered.
Can mechanical plant, equipment or water tanks be
calculated as a part of Roof U-value? No, for plantrooms exposed to the sky, Roof U-values are
calculated based on the construction of the roof, and excludes mechanical plant, etc.
GBI PRO SERIES
Can materials with low SRI, eg dark timber deck or dark
coloured tiles score under Roof Hardscape? In NRNC, can score in SM12A so long as SRI > 29
but cannot score in SM12B where SRI > 78
GBI PRO SERIES SM12A Hardscape & Greenery Application
Provide any combination of the following strategies for 50% of the site hardscape (including sidewalks, courtyards, plazas and parking lots): 1) Shade (within 5 years of occupancy); 2) Paving materials with a Solar Reflectance Index (SRI) of at least 29; 3) Open grid pavement system;
SM12B Roof Application 1) Use roofing material with a Solar Reflectance Index (SRI) equal to or greater than the value in the table below for a minimum of 75% of the roof surface; OR 2) Install a vegetated roof for at least 50% of the roof area; OR 3) Install high albedo and vegetated roof surfaces that, in combination, meet the following criteria: (Area of SRI Roof / 0.75) + (Area of vegetated roof / 0.5) ≥ Total Roof Area Roof Type Gradient SRI Low-Sloped Roof < 2:12, SRI > 78 Steep-Sloped Roof > 2:12, SRI > 29
GBI PRO SERIES
NRNC SM12B (Area of SRI/0.75) + (Area of vegetated roof / 0.5) > Total Roof Area (1,743/0.75) + (630/0.5) = 3,586 sm Total roof area = 3,221 sm hence, 1 pt achieved
High Albedo
Vegetated
Roof
Hardscape w
high albedo
GBI PRO SERIES
NRNC RNC
EE4 RE Based on actual usage
EE3 RE Based on the total common area energy usage and is proportionally based on GFA of the project.
SM4 Landscape The computation of the landscape coverage area is proportionally based on the GFA of the project.
SM11 Greenscape & Water Bodies The computation of the greenscape and water bodies coverage area is proportionally based on the GFA of the project.
SM12 Greenery (Hardscape) The computation of the hardscape coverage area is proportionally based on GFA of the project.
SM12 Hardscape The computation of the hardscape coverage area is proportionally based on GFA of the project.
GBI PRO SERIES
NRNC RNC SM10 Parking Capacity The computation of the parking capacity is proportionally based on GFA of the project.
WE3 Irrigation Based on area of landscape irrigation needs defined in SM4.
WE3 Irrigation Based on area of landscape irrigation needs defined in SM11.
WE1 Rainwater Harvesting Based on actual usage including area of landscape irrigation defined in SM4.
WE1 Rainwater Harvesting Based on actual usage including area of landscape irrigation defined in SM11.
IN1 Herb Garden Based on area of landscape defined in SM4.
IN1 Herb Garden Based on area of landscape defined in SM11.
GBI PRO SERIES
Clause 5.2 OTTV applies to building envelope, where OTTV < 50 W/m2
Clause 5.5 Roof U-value refers to the thermal transmittance of the roof, where Roof U-value < 0.4 - 0.6 W/m2K
Clause 5.6 RTTV applies to roof with skylights, where RTTV < 25 W/m2
SUMMARY
top related