2. Agenda
• Why Insulation ???
• Energy Conservation Building Code
• Insulation
– Energy Conservation Building Code
– Selection Criteria
– Insulation Material – Comparison
• Roof System
• Wall System
4. Where Energy goes from a house…
Energy Costs are going through
the roof, walls and windows
5. Energy Demand – Roof & Wall
Need for High Efficient, Insulated Building Envelope
6. The Most Cost-effective Method for
Decreasing Greenhouse Gas Emissions
Building
Insulation
Curbing Global Energy Demand Growth: The Energy Productivity Opportunity Diana Farrell, McKinsey Global Institute May 2007
10. U Value
• Amount heat transmitted in
– unit time
– through unit area of a material or construction and the
boundary air films,
– induced by unit temperature difference between the
environments on each side.
– Units of U are W/m2-ºC (Btu/h-ft2-°F)
– U = k/t (k = thermal conductivity of material & t =
thickness)
Area = 1 m2
T1 = 1oC
U = 13 W/sqm K
(6” RCC Slab)
T2 = 0oC
11. R Value – Thermal resistance
• The reciprocal of the time rate of heat flow
– through a unit area
– induced by a unit temperature difference between two
defined surfaces of material or construction
– Units of R are m2-°C/W (h-ft2-°F/Btu).
– R = 1/U = t/k
(k = thermal conductivity of material & t = thickness)
12. Selection Criteria – Insulation System for
Concrete Building Envelope
• Thermal Performance
– Selection – Thermal Resistance (R-Value) – not on
density & thickness
– Eliminates or minimizes thermal bridging – Ideal Location
– Durable (weather-ability)
• Functional
– Absorbs minimum moisture
– Should not be exposed to fire risks
– Safe & Durable (aging and functional use)
14. Product Comparison–Moisture
Absorption
• Insulation should absorb minimum moisture for best
thermal performance
– Very low water absorption per ASTM C578 standard
Property XPSa EPSa SPUb
Water Absorption, Vol. %
< 0.3c 2.0 - 4.0c 5.0d
Water Vapor Permeance
perm 1.1e 2.0 - 5.0e 2.5 - 3.0e
ng/Pa.s.m2 63 115 - 287 144 - 176
Thermal Resistance
°F.ft2.h/btu 5.0 3.1 - 4.2 6.2
Km2/W 0.88 0.55 - 0.74 1.10
XPS – Extruded Polystyrene ; EPS – Expanded Polystyrene ; SPU – Sprayed Polyurethane
Notes : a. Data from ASTM C-578 ; b. Data from ASTM C-1029; c. Tested 24 hr ; d. Tested 96 hr ;
e. Desiccant Method
15. Product Comparison – R Value retention
CRREL : 80% Minimum Acceptable
• Moisture content affects thermal resistance
– Select an insulation product ( for building envelope ) which
retains its thermal resistance – R Value
Retain R
Value v/s
Exposure
to time @
70% RH
XPS
New Wetting Curves for Common Roof Insulations, U.S. Army Corps of Engineers
Cold Regions Research and Engineering Laboratory (CRREL) April 1991
21. Roof System – U Values
Chemical Waterproofing Chemical
Layer Cement Screed Waterproofing Layer Brick Batt Coba
150
75
75
25
200
200
RCC RCC
Slab Slab
U Value : 3.19 W/m2.K U Value : 2.61 W/m2.K
U Value for 24 hour use : 0.261 W/m2.K
As per ECBC
U Value for daytime use : 0.409 W/m2.K
Geo Textile
Tile
Screed Water Proofing
Layer
Extruded Polystyrene Insulation
Screed
U Value: 0.237 W/m2.K
RCC Slab
A layer of Insulation reduces U value by >10 times
22. Roof System
Screed Pebbles /
Gravels Tile
Protective Membrane
Pavers (Geo Textile)
Water Proofing
Extruded Polystyrene Layer
Insulation Material
Screed Mortar Concrete
Slab
24. Long Lasting Durability – Dallas
Forth Worth International Airport
Project Highlights – PRMA System
• 3,036 squares re-roofed
• 88% of existing insulation reused
• $180,000 saved in new material cost
• $15,000 saved in hauling/landfill
• $100,000 saved in labor costs
Environmental Benefits
• Usable insulation recycled
• New product resource consumption minimized
• Saving in Fossil fuels
• Recycled insulation continues to save energy
27. U VALUE COMPARISON – WALL SYSTEM
Single (Brick) Wall Single (Brick) Wall Double Wall (Brick)
+ ACP with air gap
ACP
9”
thick
cement air
plaster gap
U value: ~1.78 U value: ~1.40 U value: ~0.93
insulation on
external
fascade
U value: ~0.39 U value: ~0.40 U value: ~0.37
Single (Brick) Wall + Double Wall + air gap +
Brick Wall + ACP
50mm Insulation 50mm insulation
+ 50mm
Insulation Source: Owens Corning
Unit in W/m2.K
