Building Insu. for different climates
Applied Specification and Working Details of Building Insulation
for different Climatic Zones of Iran
Morteza Kasmai, Dr. Mohamad Behrooz Kari, Nadereh Nazari, Farhang Tahmasebi
Consultants: Dr. Mohamad Taghi Rezaei Hariri, Dr. Jamshid Reyazi, Dr. Ali Assghar Saed Samiee
Building and Housing Rerearch Center
Affiliated to the Ministry of Housing and Urban Development
BHRC Publication Number: R –507, Tehran, 2009
Abstract
Although in today’s world building insulation due to its strong effect on consumption of non-renewable energy is significantly important, it has been neglected in our country and in almost the whole country using of building insulation is scare. In this way, we are losing a grate amount of our valuable fossil fuel every day. In This research, the common and applicable guidelines for applying insulation in main elements of building envelope (exterior walls, roof and floor), including working details, for all climatic zones of the country is presented.
Summery
Although in today’s world building insulation due to its strong effect on consumption of non-renewable energy is significantly important, it has been neglected in our country and in almost the whole country using of building insulation is scare. In this way, we are losing a grate amount of our valuable fossil fuel every day. In This research, the common and applicable guidelines for applying insulation in main elements of building envelope (exterior walls, roof and floor), including working details, for all climatic zones of the country is presented. The research has been conducted in 3 phases.
1- Collecting information
Preliminarily investigations revealed that one of the main reasons for rare use of building insulation in recent housing and building development in the country is the complexity of related construction details and application of these details to common construction systems being used in the country. To come up with a design solution for this problem, following data and information have been collected and studied:
– Available resources and documents on using thermal insulation in building envelope
– Interstate research results on using insulation layers in building envelope
– Iranian National Building Code, Building Regulations, Standards and Specifications
for construction details of building envelope
– Working Details being used by leads consulting engineers of the country for different elements of building envelope
The collected information in this phase have been studied, discussed, and criticized by colleagues and consultants of the project. As a result of this discussion, having in mind the narrated results gathered by studying collected resources and documents about use of thermal insulation in building envelope, the following recommendations and guidance for conducting working details of different elements of building envelope have been suggested:
1- Fire hazard and fire protection considerations in relation to the position and specification of insulation layer
2- Necessity of insulation solidity or connection in relation to thermal bridges
3- Application of moisture and vapor barriers where its needed
4- Physical damage protection of insulation layers
5- Installation methods of insulation layers for different elements of building envelope by appropriate screws or angled tie brackets
6- Considering the wide of air layer in cavity walls in relation to conventional heat transfer
7- Number, position and appropriate form of tie brackets for junction of different layers of cavity walls
8- Application of appropriate insulation material in relation to their Permeability and conductivity for different climatic zones of the country
9- Application of appropriate material in relation to their density strength and Permeability for roof insulation
2- Climatic analysis
Since climatic condition of a given place will affect the desired specification (conductivity and permeability) of insulation layers of building envelope, considering two climatic factors of 256 climatology stations, temperature and relative humidity, different cities were classified.
To classify different cities in according to their temperature conditions first, yearly Heating and Cooling Degree Days of these cities have been calculated and to consider the differences between the long run running cost and utilization cost of cooling and heating the building, in calculating the Total Degree Days of these cities the Cooling Degree Days has been multiplied by 1.25 to 2.5, according to the vapor pressure of the given month. To show the importance of applying thermal insulation in building envelope in different places, effective design strategies for these places have been conducted. To draw these strategies, temperature and humidity data of 256 stations were plotted on Building Bioclimatic Chart. To show the priority of main strategies for given places, the yearly percentage of following strategies for the mentioned stations were calculated.
– Conventional Heating – Active Solar
– Passive Solar – Internal Gain
– Comfort Zone – Natural Ventilation
– High Mass – Evaporative Cooling
– Air Conditioning
To study and compare the annual percentage of Heating and Cooling needs of common buildings (buildings that in their design processes effective design strategies were not considered) in different cities, the following assumptions were made:
– Heating need = Conventional Heating + Active Solar + Passive Solar
– Cooling need (arid climate) = Air Conditioning + Evaporative Cooling + High Mass
– Cooling need (arid climate) = Air Conditioning + Natural Ventilation
The result of this study revealed that in almost all of the 256 stations there are approximate needs of heating, cooling, or both to bring the living spaces to comfort zone, so application of thermal insulation in building envelope is highly recommended.
In this research, the priority and importance of applying thermal insulation to different elements of building envelope in different parts of the country was shown by calculating and comparing annual Total Degree Days and annual percentage of Heating and Cooling needs. The end result of these calculations showed that considering the priority of thermal insulation implication in building envelope, all parts of the country could be classified in 4 groups:
Group 1 – Low priority, Degree Days < 2500
Group 2 – Medium priority, 2500 >Degree Days < 3000
Group 3 – High priority, 3000 >Degree Days < 3500
Group 4 – Very High priority, Degree Days > 3500
To take into consideration the effect of moisture and humidity in selection and application of thermal insulation for building envelope, vapor presser of mentioned stations were studied. According to the result of this study and the related recommendations, stations that their vapor pressure in hottest month of the year was higher than 20 HP were considered as hummed stations. Almost all of the cities located in narrow southern shore of Caspian Sea and northern shore of Persian Golf and Amman Sea are hummed and named as hummed climate. Use of vapor barrier with permeable insulation material is recommended in this climate. The rest of the stations are in arid climate.
3- Working Details
In final phase of this research, at first, with respect to different climatic conditions of the country in respect to application of thermal insulation in different elements of building envelope, guidelines for installation of thermal layers with spatial screws, cavity wall ties and angled tie brackets, installation of vapor barriers and moisture barriers, appropriate methods of installing insulation layers in cavity walls and safety factors in installation process of thermal insulation were presented. Preparing working details for installation of thermal insulation layers in different opaque exterior elements of existing and new buildings was the next part of this phase and the working details were recommended in the following order.
3-1 Existing Walls
For the existing walls, combination of 4 different insulation materials (glass wool, rock wool, expanded polystyrene and polyurethane) and 3 different external finishing materials (facing brick, facing stone tile and brick with cement plaster) were presented to be installed on existing exterior walls.
3-1-1 Glass wool + facing brick, cement plaster or facing stone tile
3-1-2 expanded polystyrene + facing stone, or facing brick
3-1-3 polyurethane + facing brick, cement plaster or facing stone
3-1-4 rock wool + facing stone, cement plaster or facing brick
3-2 Solid Walls
For this type of walls combination with 4 available and commonly used insulation materials, rock wool or glass wool (with vapor barrier) and expanded polystyrene or polyurethane, for external thermal insulation and internal thermal insulation are presented
3-2-1 Solid 11 cm. brick wall with facing brick, or cement plaster
3-2-2 Solid 22 cm. brick wall with facing brick, facing stone or cement plaster
3-2-3 Solid 15 cm. Concrete wall with facing brick, facing stone or cement plaster
3-2-4 Solid 20 cm. masonry or concrete block wall with facing brick, facing stone or cement plaster
3-3 Composite Walls
For this type of walls, combination of 4 available and commonly used insulation materials, rock wool or glass wool (with vapor barrier) and expanded polystyrene or polyurethane, for external thermal insulation and internal thermal insulation are presented.
3-3-1 External 11 cm. brick wall with facing brick, or cement plaster and 22 cm. internal wall with plaster
3-3-2 Combination of tow 11 cm. brick wall, external wall with facing brick, facing stone or cement plaster and internal wall with plaster
3-3-3 External 11 cm. brick wall with facing brick, facing stone or cement plaster and internal 15 cm. concrete wall with plaster
3-3-4 External 11 cm. brick wall with facing brick, facing stone or cement plaster and internal 20-cm. masonry or concrete block wall with plaster
3-4 Flat Roofs
3-4-1 Solid concrete or masonry roof with thermal insulation under water insulation
3-4-2 Solid concrete or masonry roof with thermal insulation above water insulation
3-5 Composite Flat Roofs
3-6 Pitched Roofs
3-6-1 Corrugated iron sheet with thermal insulation above suspended ceiling
3-6-2 Corrugated iron sheet with thermal insulation beneath suspended ceiling
3-6-3 Gable roof
3-6-4 Corrugated asbestos cement roof for hummed and arid climates
3-6-3 Sandwich panel roof
3-7 Pitched Straight Barrel Vault Roofs
3-7-1 Straight Barrel Vault roof covered with asbestos cement tiles for hummed and arid climates
3-7-2 Straight Barrel Vault covered with gable roof
3-8 Pitched Concrete Slab Roofs
3-8-1 Concrete Slab roof covered with gable for hummed and arid climates
3-8-2 Concrete Slab roof covered with corrugated asbestos cement for hummed and arid climates
3-8-3 Concrete Slab roof covered with asbestos cement tiles for hummed and arid climates
3-9 Floors in contact with natural ground
3-10 Floors in contact with unheated space
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