Ventilated attics are prone to moisture problems in the Coastal Pacific Northwest climate. This presentation discusses recent research investigating the causes of these issues, and presents cutting edge findings regarding potential solutions.
Vapour Permeable Air Barriers: Real World Evaluation - What Works, What Doesn...Lorne Ricketts
As insulation and airtightness requirements increase, vapour permeable liquid and self-adhesive air barrier membrane products are rapidly gaining traction in the North American marketplace. This presentation looks at real world testing of various types of these membranes and identifies potential strengths and weakness of these types of products.
Airflow in Mid to High-rise Multi-Unit Residential BuildingsRDH Building Science
Agenda
1. Understand typical ventilation practices for multi-unit residential buildings including corridor pressurization systems.
2. Understand performance issues associated with the ventilation of high-rise multi-unit residential buildings including the impacts of stack effect, wind, and airtightness.
3. Learn about how the theory of airflow relates well to what is
measured in-service, but that the well understood theory is not always taken into account in design.
State of the Art Review of Unvented Sloped Wood-Framed Roofs in Cold ClimatesRDH Building Science
Typical residential house construction in North America has long had vented attics above living space with the insulation and air control layer at the ceiling plane of the living space. Except for documented wintertime condensation issues in cold climates, such vented attics generally perform quite well, provided that they are ventilated adequately and air leakage from the interior is prevented. However, architects and designers are moving away from empty attics by using the attic space as conditioned storage or bonus rooms, or by designing larger interior volumes with cathedral ceilings. The practical challenges of ventilating cathedralized attics and cathedral ceilings have been significant, both because of increased geometrical complexity and because of the number of penetrations typically required for services.
Spray foam has been used successfully in tens of thousands of unvented roof assemblies throughout North America but some concerns remain in the building industry that these assemblies are inferior to ventilated roof assemblies. The National Building Code of Canada, in particular, makes it difficult for designers to use unvented roof assemblies, even using designs that are approved in similar building codes in the United States and have been proven to be durable, high-performing options. Over the past decade, the authors have been directly involved with studies of both 0.5 pcf (8 kg/m3) open cell spray foam, and 2.0 pcf (32 kg/m3) closed cell spray foam in unvented roof assemblies in various climates with continuous monitoring of temperature and moisture conditions. This paper provides a literature review of research that has been conducted on wood-framed sloped unvented roof assemblies, but will focus on results from a field monitoring study of sloped unvented wood roofs in partnership with the University of Waterloo, as well as a field survey that opened roofs and removed samples from aged unvented roof assemblies.
Presented at the 15th Canadian Conference on Building Science and Technology.
Current Issues with Ventilated Attics
Case Study of Repairs
Attic Roof Hut Research & Monitoring Study – Key Findings
Performance of Potential Solutions
Ongoing Research & Field Trials
Airtightness of Large Buildings - Where We're At and Where We're GoingLorne Ricketts
This document discusses airtightness testing of large buildings. It begins by outlining the impacts of air leakage on building energy consumption, indoor air quality, durability, comfort and more. Despite this, building energy codes provide little guidance on air barriers or verification of performance. The document then reviews differences between testing houses versus high-rises, common test methods and standards, and examples of performance requirements in different jurisdictions. It presents data on airtightness test results and the impact of requirements. It also discusses trends in air barrier materials, impacts of testing, and clarifies the difference between airtightness and actual air leakage.
The Problem With and Solutions for Ventilated AtticsGraham Finch
Presentation from 30th RCI Annual Convention and Tradeshow in San Antonio, TX - March 9, 2015.
Peer reviewed paper and presentation covers review of current issues with ventilated attics in the Pacific Northwest with case studies, the latest research and potential solutions to address mold growth and other moisture issues.
This document summarizes a case study evaluating the energy savings from a deep energy retrofit of a multi-unit residential building in Vancouver, BC. It found that upgrading the building enclosure through exterior wall insulation, triple-glazed windows, and air sealing reduced the building's energy use intensity by 19% from 226 to 183 kWh/m2/yr, matching the 20% savings predicted by energy modeling. Measured savings included a 33% reduction in suite electricity use and a 63% drop in electric baseboard heating. Further energy and cost savings may be possible by upgrading the building's mechanical ventilation system. The study demonstrates that deep energy retrofits can significantly cut energy consumption in existing multi-unit residential buildings.
Challenges Related to Measuring and Reporting Temperature-Dependent Apparent ...RDH Building Science
In North America, the apparent thermal conductivity (and R-value) of building insulation materials is commonly reported at a mean temperature of 24°C (75°F) and practitioners typically assume thermal properties remain constant over the range of temperatures that are experienced in building applications. Researchers have long known and acknowledged the fact that the thermal properties of most building insulation materials change with temperature. There has been little more than academic reason to measure and report this effect. However, interest in temperature-dependent thermal performance has grown with the introduction of new materials, increasing concerns regarding energy performance, and the development of tools transient energy, thermal, and hygrothermal simulation software packages (e.g. Energy Plus, HEAT2, WUFI etc.) that have capacity to account for temperature-dependence. Continue reading by clicking the Download link to the left.
Presented at the 15th Canadian Conference on Building Science and Technology.
Vapour Permeable Air Barriers: Real World Evaluation - What Works, What Doesn...Lorne Ricketts
As insulation and airtightness requirements increase, vapour permeable liquid and self-adhesive air barrier membrane products are rapidly gaining traction in the North American marketplace. This presentation looks at real world testing of various types of these membranes and identifies potential strengths and weakness of these types of products.
Airflow in Mid to High-rise Multi-Unit Residential BuildingsRDH Building Science
Agenda
1. Understand typical ventilation practices for multi-unit residential buildings including corridor pressurization systems.
2. Understand performance issues associated with the ventilation of high-rise multi-unit residential buildings including the impacts of stack effect, wind, and airtightness.
3. Learn about how the theory of airflow relates well to what is
measured in-service, but that the well understood theory is not always taken into account in design.
State of the Art Review of Unvented Sloped Wood-Framed Roofs in Cold ClimatesRDH Building Science
Typical residential house construction in North America has long had vented attics above living space with the insulation and air control layer at the ceiling plane of the living space. Except for documented wintertime condensation issues in cold climates, such vented attics generally perform quite well, provided that they are ventilated adequately and air leakage from the interior is prevented. However, architects and designers are moving away from empty attics by using the attic space as conditioned storage or bonus rooms, or by designing larger interior volumes with cathedral ceilings. The practical challenges of ventilating cathedralized attics and cathedral ceilings have been significant, both because of increased geometrical complexity and because of the number of penetrations typically required for services.
Spray foam has been used successfully in tens of thousands of unvented roof assemblies throughout North America but some concerns remain in the building industry that these assemblies are inferior to ventilated roof assemblies. The National Building Code of Canada, in particular, makes it difficult for designers to use unvented roof assemblies, even using designs that are approved in similar building codes in the United States and have been proven to be durable, high-performing options. Over the past decade, the authors have been directly involved with studies of both 0.5 pcf (8 kg/m3) open cell spray foam, and 2.0 pcf (32 kg/m3) closed cell spray foam in unvented roof assemblies in various climates with continuous monitoring of temperature and moisture conditions. This paper provides a literature review of research that has been conducted on wood-framed sloped unvented roof assemblies, but will focus on results from a field monitoring study of sloped unvented wood roofs in partnership with the University of Waterloo, as well as a field survey that opened roofs and removed samples from aged unvented roof assemblies.
Presented at the 15th Canadian Conference on Building Science and Technology.
Current Issues with Ventilated Attics
Case Study of Repairs
Attic Roof Hut Research & Monitoring Study – Key Findings
Performance of Potential Solutions
Ongoing Research & Field Trials
Airtightness of Large Buildings - Where We're At and Where We're GoingLorne Ricketts
This document discusses airtightness testing of large buildings. It begins by outlining the impacts of air leakage on building energy consumption, indoor air quality, durability, comfort and more. Despite this, building energy codes provide little guidance on air barriers or verification of performance. The document then reviews differences between testing houses versus high-rises, common test methods and standards, and examples of performance requirements in different jurisdictions. It presents data on airtightness test results and the impact of requirements. It also discusses trends in air barrier materials, impacts of testing, and clarifies the difference between airtightness and actual air leakage.
The Problem With and Solutions for Ventilated AtticsGraham Finch
Presentation from 30th RCI Annual Convention and Tradeshow in San Antonio, TX - March 9, 2015.
Peer reviewed paper and presentation covers review of current issues with ventilated attics in the Pacific Northwest with case studies, the latest research and potential solutions to address mold growth and other moisture issues.
This document summarizes a case study evaluating the energy savings from a deep energy retrofit of a multi-unit residential building in Vancouver, BC. It found that upgrading the building enclosure through exterior wall insulation, triple-glazed windows, and air sealing reduced the building's energy use intensity by 19% from 226 to 183 kWh/m2/yr, matching the 20% savings predicted by energy modeling. Measured savings included a 33% reduction in suite electricity use and a 63% drop in electric baseboard heating. Further energy and cost savings may be possible by upgrading the building's mechanical ventilation system. The study demonstrates that deep energy retrofits can significantly cut energy consumption in existing multi-unit residential buildings.
Challenges Related to Measuring and Reporting Temperature-Dependent Apparent ...RDH Building Science
In North America, the apparent thermal conductivity (and R-value) of building insulation materials is commonly reported at a mean temperature of 24°C (75°F) and practitioners typically assume thermal properties remain constant over the range of temperatures that are experienced in building applications. Researchers have long known and acknowledged the fact that the thermal properties of most building insulation materials change with temperature. There has been little more than academic reason to measure and report this effect. However, interest in temperature-dependent thermal performance has grown with the introduction of new materials, increasing concerns regarding energy performance, and the development of tools transient energy, thermal, and hygrothermal simulation software packages (e.g. Energy Plus, HEAT2, WUFI etc.) that have capacity to account for temperature-dependence. Continue reading by clicking the Download link to the left.
Presented at the 15th Canadian Conference on Building Science and Technology.
Thermal bridges in concrete construction solutions to address energy code co...RDH Building Science
This document discusses the significant thermal impact that uninsulated concrete slab edges and balconies can have on the effective R-value and energy performance of building walls. While balconies make up a small percentage of total wall area, their low R-value of around R-1 can reduce the overall wall R-value by 40-60%. This negatively impacts energy code compliance and increases heating and cooling loads. The document evaluates different solutions for insulating slab edges and balconies, such as structural cut-outs, insulation wraps, and manufactured thermal breaks. Thermal breaks in particular are shown to improve the overall wall R-value and help meet increasing energy code requirements.
NBEC 2014 - Airflow in Mid to High-rise Multi-Unit Residential BuildingsRDH Building Science
Introduction & Background
- Testing and Measurement Program
- Measured Ventilation Rates (PFT testing)
- Cause of Ventilation Rates
- Extension of Study Findings
- Conclusions & Recommendations
State of the Art of Multi-Unit Residential Building Airtightness: Test Procedures, Performance, and Industry Involvement
Outline:
- Airtightness Test Procedures & Equipment
- Worldwide Regulatory Requirements & Targets for Airtightness
- Airtightness of Multi-Unit Residential Buildings
- Air Barrier Systems
- Industry Preparedness for Airtightness Testing
Moisture Buffering and Ventilation Strategies to Control Indoor Humidity in a...RDH Building Science
Control of the indoor humidity in a marine climate is a challenge, especially under operating conditions where high indoor humidity is a norm. Outdated mechanical equipment, inefficient ventilation design, and occupants’ life styles are some of the contributing factors to high indoor humidity. In this field experimental study, the moisture buffering potential of unfinished drywall in reducing daily indoor humidity peaks, coupled with various ventilation strategies are investigated. Two identical test buildings exposed to real climatic conditions in Burnaby, BC are monitored under varying ventilation rates and schemes.
The interior of the test building is clad with unfinished drywall, while the control building is covered with polyethylene, which has negligible moisture buffering. In this way, the moisture buffering potential of drywall under four test cases is isolated. Under the test cases, the indoor air quality in terms of CO2 concentration, and ventilation heat loss of the two buildings are also evaluated.
The results show that the moisture buffering potential of drywall effectively regulates indoor humidity peaks, and maintains relative humidity levels within acceptable thresholds, when coupled with adequate ventilation as recommended by ASHRAE. When coupled with time-controlled and demand-controlled ventilation schemes, the moisture buffering effect of drywall shows competing benefits.
Presented at the 15th Canadian Conference on Building Science and Technology
This document summarizes key differences between window rating standards in North America (NFRC) and Europe (ISO, Passive House). There are differences in boundary conditions, window geometries, calculation methodologies, and treatment of sloped glazing that can lead to different U-value and SHGC ratings for the same window. Simulation results showed centre of glass U-values can vary by up to 23% depending on the standard used, and frame U-values vary by 11-16%. The differences are most pronounced for larger glazing cavities and affect optimal cavity sizes. Understanding these differences is important for high performance window selection.
This document summarizes a study of the performance of a corridor pressurization ventilation system in a 13-story residential building in Vancouver. Measurements found significant variations in ventilation rates between suites, with most under or over-ventilated. The study found that only 8% of intended ventilation air actually reaches the suites, with significant leakage along the ventilation path. Stack effects and wind pressures were also found to influence ventilation rates and overwhelm the mechanical pressures at times. The document recommends direct ventilation of suites and improved compartmentalization of spaces to limit natural pressures and better control ventilation.
Presentation Outline:
- What are "Super-Insulated" buildings and what are the drivers?
- Thermal bridging- problems and solutions
- Designing of highly insulated walls - insulation placement & durability considerations
- Super-Insulated wood-frame building enclosure design guide
Impact of Heating and Cooling of Expanded Polystyrene and Wool Insulations on...RDH Building Science
The thermal expansion and contraction of insulation products within conventional roof assemblies has been identified as a potential performance concern in the roofing industry. This movement can create gaps between insulation boards, which can short-circuit the insulation with respect to heat flow, and in conventional roof assemblies where the insulation also provides the substrate for the roofing membrane, insulation movement can also adversely affect the durability and integrity of the membrane and roofing system. Problems with creasing and ridging of membranes have been observed in the field, along with stress concentrations and holes around fixed penetrations. In particular, field observations have indicated that shrinkage of expanded polystyrene (EPS) insulation products may put undue stress on the roof membranes and could potentially affect the durability of styrene-butadiene-styrene (SBS) roof membranes.
To investigate these industry concerns regarding the potential effect of dimensional movement of EPS insulation on the performance of SBS membranes, laboratory testing was performed on conventional roof specimens in a purpose-built climate chamber. The roof assemblies were cooled and heated to evaluate the amount of insulation movement, and to then observe the impact of these temperature cycles on the roof assembly. This portion of the investigation in to this issue focused on recreation of the observed field condition (e.g., wrinkled membrane), and direct comparison of the relative performance of different insulation types as a first step towards determining the cause of the observed in-service wrinkling.
Presented at the 15th Canadian Conference on Building Science and Technology.
Presentation on Building Enclosure Airtightness Testing in Washington StateRDH Building Science
This document discusses building airtightness testing that was conducted in Washington State on 31 buildings. It provides an overview of airtightness testing procedures and requirements under the 2009 and 2012 energy codes. Test results showed that while an airtightness of 0.4 cfm/ft2 is attainable, achieving it requires repetitive simple details, experienced teams, and coordination between designers, contractors and trades to minimize air leakage.
NBEC 2014 - Flow Exponent Values and Implications for Air Leakage TestingRDH Building Science
- Introduction to air leakage testing
- Relationship between flow and pressure
- Case study building
- Abnormal flow exponents
- Data extrapolation to operating pressures
- Conclusions/Implications
- Further study
Achieving the Passive House criteria on a high-rise, concrete-framed building located in Vancouver, BC.
Presented at the 2017 NAPHN Conference and Expo by Eric Catania, M.Eng., BEMP, CPHD, LEED AP BD+C, PHI Accredited Passive House Certifier.
Improvements in building efficiency can significantly reduce carbon emissions and are an intrinsic component in greenhouse gas reduction targets. The Passive House concept provides a framework for high-performance building that is growing in popularity in Canada, and particularly in the Pacific Northwest. The Passive House standard requires its buildings to achieve specific performance values for heating energy use intensity, total energy use intensity, spatial temperature variation, heat recovery ventilation performance and air leakage rate. The promised co-benefits of Passive Houses include superior thermal comfort and indoor air quality.
Passive House design is not prescriptive and can incorporate many different design aspects. The wall assembly is no exception. This paper evaluates the hygrothermal performance of a deep-stud wall assembly of a Passive House in Victoria, BC, with regards to moisture durability. The concern with deep or doublestud wall assemblies is the combined effects of reduced drying with wall configurations that place moisture sensitive materials in riskier locations. Consequently, enclosure monitoring was undertaken in an occupied six-plex over the period of one year.
The enclosure monitoring sensor packages were installed in strategic locations in the wall assembly to monitor the conditions of the assembly. The assemblies were evaluated based on the results of an empirical mold risk index. The wall assembly appears to perform acceptably, with minor concerns of mold growth on the North wall. Air leakage is a significant concern for cavity insulated walls, but the airtightness requirements of Passive house minimize this risk.
Presented at the 15th Canadian Conference on Building Science and Technology.
We are going to present information on the following topics relating to Air Tightness Testing.
What is Air Leakage –The common Air Leakage Paths - General Principles & the Air Line - Building Tight – Walls, Dry Lining & Ceilings - Harron Homes some specific detail - ATTMA Competent persons Scheme & Certificate Lodgement - Temporary Sealing - Checklist
The objective of this presentation is to provide you with an overview on what is Air Leakage / Air Tightness Testing, what the general principles are when it comes to achieving the required levels of Air Tightness for compliance with the Building Regs.
We also provide some guidelines on how you can achieve it.
We outline the changes to Air Tightness testing with the introduction of the ATTMA Competent persons scheme & Certificate Lodgement, along with what is and what isn’t acceptable regarding temporary sealing.
Conventional Roofing Assemblies: Measuring the Thermal Benefits of Light to D...RDH Building Science
Presentation Overview:
• Conventional Roofing Designs
and Current Issues
• Conventional Roofing Field
Monitoring and Research
Program
• Measured Insulation Performance
• Selecting Roofing Membrane
Color and Insulation Strategy for
Optimum Energy Efficiency
• Case Studies
Overview:
- Background
- Net Zero Building Enclosure Targets & Potential Savings
- Interior and Exterior Building Enclosure Retrofit Strategies
- Hygrothermal Considerations & Risk Assessment Evaluation Methodology
- Economics of Net Zero Building Enclosure Retrofits
Energy Efficient Building Enclosure Design Guidelines for Wood-Frame BuildingsRDH Building Science
The document summarizes a new guide for designing energy efficient building enclosures for wood-frame buildings. It provides an overview of the guide's contents, which include chapters on building and energy codes, moisture and thermal control strategies, recommendations for highly insulated wall and roof assemblies, and construction detailing. The guide aims to help designers meet current and upcoming energy code requirements with wood-frame construction and provides guidance on enclosure designs for different climate zones in North America.
Ever increasing thermal performance requirements for wood-frame walls have had a dramatic impact on how we build walls. To meet these targets, exterior insulation is becoming more and more common, and methods to support the cladding are required that are strong and rigid, yet do not create significant thermal bridging through the insulation. This presentation discusses the results of recent structural testing of various different arrangements on long fasteners through exterior insulation as a method of supporting cladding while limiting thermal bridging.
Building enclosure presentation and studyMark Smith
The document discusses building enclosure layers and energy codes. It provides details on vapor control layers, thermal control layers, air control layers, and liquid water control layers. Key points include common materials used for each layer, requirements that vary by climate zone and state codes, and common installation errors to avoid. Michigan uses the 2015 IECC code for residential and 2013 ASHRAE 90.1 code for commercial buildings.
Presentation by BSRIA Compliance's Andy McGrath looking at why airtightness testing is a requirement of the Building Regulations. Will look at:
What causes Air Leakage
Common Air Leakage points
Part L Building Regulations & Testing regimes
Este documento describe la mortalidad materna y la hemorragia obstétrica. Resume las definiciones, causas, factores de riesgo, clasificaciones, tratamientos y estadísticas relacionadas con la mortalidad materna y la hemorragia obstétrica. La hemorragia obstétrica es una de las principales causas de muerte materna y afecta desproporcionadamente a países en desarrollo. Un tratamiento rápido y efectivo es crucial para prevenir muertes.
Thermal bridges in concrete construction solutions to address energy code co...RDH Building Science
This document discusses the significant thermal impact that uninsulated concrete slab edges and balconies can have on the effective R-value and energy performance of building walls. While balconies make up a small percentage of total wall area, their low R-value of around R-1 can reduce the overall wall R-value by 40-60%. This negatively impacts energy code compliance and increases heating and cooling loads. The document evaluates different solutions for insulating slab edges and balconies, such as structural cut-outs, insulation wraps, and manufactured thermal breaks. Thermal breaks in particular are shown to improve the overall wall R-value and help meet increasing energy code requirements.
NBEC 2014 - Airflow in Mid to High-rise Multi-Unit Residential BuildingsRDH Building Science
Introduction & Background
- Testing and Measurement Program
- Measured Ventilation Rates (PFT testing)
- Cause of Ventilation Rates
- Extension of Study Findings
- Conclusions & Recommendations
State of the Art of Multi-Unit Residential Building Airtightness: Test Procedures, Performance, and Industry Involvement
Outline:
- Airtightness Test Procedures & Equipment
- Worldwide Regulatory Requirements & Targets for Airtightness
- Airtightness of Multi-Unit Residential Buildings
- Air Barrier Systems
- Industry Preparedness for Airtightness Testing
Moisture Buffering and Ventilation Strategies to Control Indoor Humidity in a...RDH Building Science
Control of the indoor humidity in a marine climate is a challenge, especially under operating conditions where high indoor humidity is a norm. Outdated mechanical equipment, inefficient ventilation design, and occupants’ life styles are some of the contributing factors to high indoor humidity. In this field experimental study, the moisture buffering potential of unfinished drywall in reducing daily indoor humidity peaks, coupled with various ventilation strategies are investigated. Two identical test buildings exposed to real climatic conditions in Burnaby, BC are monitored under varying ventilation rates and schemes.
The interior of the test building is clad with unfinished drywall, while the control building is covered with polyethylene, which has negligible moisture buffering. In this way, the moisture buffering potential of drywall under four test cases is isolated. Under the test cases, the indoor air quality in terms of CO2 concentration, and ventilation heat loss of the two buildings are also evaluated.
The results show that the moisture buffering potential of drywall effectively regulates indoor humidity peaks, and maintains relative humidity levels within acceptable thresholds, when coupled with adequate ventilation as recommended by ASHRAE. When coupled with time-controlled and demand-controlled ventilation schemes, the moisture buffering effect of drywall shows competing benefits.
Presented at the 15th Canadian Conference on Building Science and Technology
This document summarizes key differences between window rating standards in North America (NFRC) and Europe (ISO, Passive House). There are differences in boundary conditions, window geometries, calculation methodologies, and treatment of sloped glazing that can lead to different U-value and SHGC ratings for the same window. Simulation results showed centre of glass U-values can vary by up to 23% depending on the standard used, and frame U-values vary by 11-16%. The differences are most pronounced for larger glazing cavities and affect optimal cavity sizes. Understanding these differences is important for high performance window selection.
This document summarizes a study of the performance of a corridor pressurization ventilation system in a 13-story residential building in Vancouver. Measurements found significant variations in ventilation rates between suites, with most under or over-ventilated. The study found that only 8% of intended ventilation air actually reaches the suites, with significant leakage along the ventilation path. Stack effects and wind pressures were also found to influence ventilation rates and overwhelm the mechanical pressures at times. The document recommends direct ventilation of suites and improved compartmentalization of spaces to limit natural pressures and better control ventilation.
Presentation Outline:
- What are "Super-Insulated" buildings and what are the drivers?
- Thermal bridging- problems and solutions
- Designing of highly insulated walls - insulation placement & durability considerations
- Super-Insulated wood-frame building enclosure design guide
Impact of Heating and Cooling of Expanded Polystyrene and Wool Insulations on...RDH Building Science
The thermal expansion and contraction of insulation products within conventional roof assemblies has been identified as a potential performance concern in the roofing industry. This movement can create gaps between insulation boards, which can short-circuit the insulation with respect to heat flow, and in conventional roof assemblies where the insulation also provides the substrate for the roofing membrane, insulation movement can also adversely affect the durability and integrity of the membrane and roofing system. Problems with creasing and ridging of membranes have been observed in the field, along with stress concentrations and holes around fixed penetrations. In particular, field observations have indicated that shrinkage of expanded polystyrene (EPS) insulation products may put undue stress on the roof membranes and could potentially affect the durability of styrene-butadiene-styrene (SBS) roof membranes.
To investigate these industry concerns regarding the potential effect of dimensional movement of EPS insulation on the performance of SBS membranes, laboratory testing was performed on conventional roof specimens in a purpose-built climate chamber. The roof assemblies were cooled and heated to evaluate the amount of insulation movement, and to then observe the impact of these temperature cycles on the roof assembly. This portion of the investigation in to this issue focused on recreation of the observed field condition (e.g., wrinkled membrane), and direct comparison of the relative performance of different insulation types as a first step towards determining the cause of the observed in-service wrinkling.
Presented at the 15th Canadian Conference on Building Science and Technology.
Presentation on Building Enclosure Airtightness Testing in Washington StateRDH Building Science
This document discusses building airtightness testing that was conducted in Washington State on 31 buildings. It provides an overview of airtightness testing procedures and requirements under the 2009 and 2012 energy codes. Test results showed that while an airtightness of 0.4 cfm/ft2 is attainable, achieving it requires repetitive simple details, experienced teams, and coordination between designers, contractors and trades to minimize air leakage.
NBEC 2014 - Flow Exponent Values and Implications for Air Leakage TestingRDH Building Science
- Introduction to air leakage testing
- Relationship between flow and pressure
- Case study building
- Abnormal flow exponents
- Data extrapolation to operating pressures
- Conclusions/Implications
- Further study
Achieving the Passive House criteria on a high-rise, concrete-framed building located in Vancouver, BC.
Presented at the 2017 NAPHN Conference and Expo by Eric Catania, M.Eng., BEMP, CPHD, LEED AP BD+C, PHI Accredited Passive House Certifier.
Improvements in building efficiency can significantly reduce carbon emissions and are an intrinsic component in greenhouse gas reduction targets. The Passive House concept provides a framework for high-performance building that is growing in popularity in Canada, and particularly in the Pacific Northwest. The Passive House standard requires its buildings to achieve specific performance values for heating energy use intensity, total energy use intensity, spatial temperature variation, heat recovery ventilation performance and air leakage rate. The promised co-benefits of Passive Houses include superior thermal comfort and indoor air quality.
Passive House design is not prescriptive and can incorporate many different design aspects. The wall assembly is no exception. This paper evaluates the hygrothermal performance of a deep-stud wall assembly of a Passive House in Victoria, BC, with regards to moisture durability. The concern with deep or doublestud wall assemblies is the combined effects of reduced drying with wall configurations that place moisture sensitive materials in riskier locations. Consequently, enclosure monitoring was undertaken in an occupied six-plex over the period of one year.
The enclosure monitoring sensor packages were installed in strategic locations in the wall assembly to monitor the conditions of the assembly. The assemblies were evaluated based on the results of an empirical mold risk index. The wall assembly appears to perform acceptably, with minor concerns of mold growth on the North wall. Air leakage is a significant concern for cavity insulated walls, but the airtightness requirements of Passive house minimize this risk.
Presented at the 15th Canadian Conference on Building Science and Technology.
We are going to present information on the following topics relating to Air Tightness Testing.
What is Air Leakage –The common Air Leakage Paths - General Principles & the Air Line - Building Tight – Walls, Dry Lining & Ceilings - Harron Homes some specific detail - ATTMA Competent persons Scheme & Certificate Lodgement - Temporary Sealing - Checklist
The objective of this presentation is to provide you with an overview on what is Air Leakage / Air Tightness Testing, what the general principles are when it comes to achieving the required levels of Air Tightness for compliance with the Building Regs.
We also provide some guidelines on how you can achieve it.
We outline the changes to Air Tightness testing with the introduction of the ATTMA Competent persons scheme & Certificate Lodgement, along with what is and what isn’t acceptable regarding temporary sealing.
Conventional Roofing Assemblies: Measuring the Thermal Benefits of Light to D...RDH Building Science
Presentation Overview:
• Conventional Roofing Designs
and Current Issues
• Conventional Roofing Field
Monitoring and Research
Program
• Measured Insulation Performance
• Selecting Roofing Membrane
Color and Insulation Strategy for
Optimum Energy Efficiency
• Case Studies
Overview:
- Background
- Net Zero Building Enclosure Targets & Potential Savings
- Interior and Exterior Building Enclosure Retrofit Strategies
- Hygrothermal Considerations & Risk Assessment Evaluation Methodology
- Economics of Net Zero Building Enclosure Retrofits
Energy Efficient Building Enclosure Design Guidelines for Wood-Frame BuildingsRDH Building Science
The document summarizes a new guide for designing energy efficient building enclosures for wood-frame buildings. It provides an overview of the guide's contents, which include chapters on building and energy codes, moisture and thermal control strategies, recommendations for highly insulated wall and roof assemblies, and construction detailing. The guide aims to help designers meet current and upcoming energy code requirements with wood-frame construction and provides guidance on enclosure designs for different climate zones in North America.
Ever increasing thermal performance requirements for wood-frame walls have had a dramatic impact on how we build walls. To meet these targets, exterior insulation is becoming more and more common, and methods to support the cladding are required that are strong and rigid, yet do not create significant thermal bridging through the insulation. This presentation discusses the results of recent structural testing of various different arrangements on long fasteners through exterior insulation as a method of supporting cladding while limiting thermal bridging.
Building enclosure presentation and studyMark Smith
The document discusses building enclosure layers and energy codes. It provides details on vapor control layers, thermal control layers, air control layers, and liquid water control layers. Key points include common materials used for each layer, requirements that vary by climate zone and state codes, and common installation errors to avoid. Michigan uses the 2015 IECC code for residential and 2013 ASHRAE 90.1 code for commercial buildings.
Presentation by BSRIA Compliance's Andy McGrath looking at why airtightness testing is a requirement of the Building Regulations. Will look at:
What causes Air Leakage
Common Air Leakage points
Part L Building Regulations & Testing regimes
Este documento describe la mortalidad materna y la hemorragia obstétrica. Resume las definiciones, causas, factores de riesgo, clasificaciones, tratamientos y estadísticas relacionadas con la mortalidad materna y la hemorragia obstétrica. La hemorragia obstétrica es una de las principales causas de muerte materna y afecta desproporcionadamente a países en desarrollo. Un tratamiento rápido y efectivo es crucial para prevenir muertes.
Microbiome, gut function and immunity finalElla Allred
The microbiome refers to the trillions of microorganisms that live in and on the human body. The microbiome plays a crucial role in human health, affecting functions of the immune system, digestive system, and other body systems. The microbiome is established early in life, beginning in the placenta and developing further during birth and through breastfeeding. Maintaining a healthy microbiome involves avoiding overuse of antibiotics, eating a high-fiber diet with fermented foods, limiting stress, and consuming prebiotic and probiotic supplements. Imbalances in the microbiome are linked to various diseases like IBS, IBD, and metabolic disorders.
Presented at the BCBEC Building Smart with Safe and Durable Wall Assemblies Symposium Feb 2, 2017, by Lorne Ricketts.
Ever increasing thermal performance requirements for wood-frame walls have had a dramatic impact on how we build walls. To meet these targets, exterior insulation is becoming more and more common, and methods to support the cladding are required that are strong and rigid, yet do not create significant thermal bridging through the insulation. This presentation discusses the results of recent structural testing of various different arrangements on long fasteners through exterior insulation as a method of supporting cladding while limiting thermal bridging.
This document discusses three criminal cases: the case of serial killer Cary Stayner who killed 4 women, the case of Bernard Madoff who committed the largest fraud in history, and the case of Andrea Yates who killed all of her children in under an hour. It analyzes these cases using criminal analysis approaches, identifying the types of crimes and whether they were expressive or instrumental. Rational choice theory and strain theory are applied to help understand the motivations and behaviors of Stayner and Yates. Madoff's case is examined in depth using an economic theory lens to understand his massive Ponzi scheme as a white collar crime.
The definition of a "Super-Insulated" building, with a problem and solution based look at thermal bridging. The energy codes in the Pacific Northwest are some of the most stringent, but are also the best implemented in North America. Effective R-values are considered in the Energy codes and include the impacts of insulation installation and thermal bridges. A look into the other drivers behind Super-insulation such as comfort, passive design and mold-free enclosures.
The Tradition and Science of Window Installations - Where are We Headed with ...Graham Finch
Presentation on the impact of more highly insulated and passive house wall designs and practices on the installation of windows. Presented at the 2016 Euroline technology forum.
High Performance Walls - Solutions for Thermal BridgingGraham Finch
The document provides an overview of high performance wall assemblies that minimize thermal bridging and maximize energy efficiency. It discusses recent trends toward more insulated building enclosures to meet stricter energy codes. Various strategies for constructing highly insulated wall assemblies are presented, including attaching exterior insulation. The summary examines different cladding attachment systems and compares their thermal performance, highlighting methods like clip and rail systems that reduce thermal bridging. Case studies demonstrate how these technologies have been applied to new and existing buildings.
Energy codes and standards require ever increasing thermal performance. This presentation looks at different ways to achieve higher insulation levels without compromising durability.
This visual dictionary document defines and provides images of various construction materials and components. It includes definitions and images for items like air barriers, attic ventilation materials, backhoes, batter boards, brick bonds, bulldozers, cladding types, concrete masonry units, doors, electrical components, framing elements, gypsum board, heat pumps, insulation materials, lintels, mortar joints, oriented strand board, plumbing fixtures, plywood, rebar, roofing materials, steep roof shapes and terms, stonework, vapor retarders, waterproofing, weeps holes, welded wire fabric, and window types. The document acts as a reference for many common construction items.
The front office is the nerve center of the hotel and oversees key functions like check-in, bell services, and guest relations. It can be divided into 5 areas: reception, bell services, mail/information, concierge, and cashiers/night auditors. Room clerks maintain the room rack to track occupancy and availability, check reservations, and notify housekeeping and operators when guests check-out. The registration process categorizes guests as groups, reservations, or walk-ins. Other front office roles include doormen, bellmen, elevator operators, and mail/information clerks. Automation has been sought to improve efficiency of front office, reservation, and accounting functions.
This document summarizes front office operations in a hotel. It discusses the four stages of the guest cycle: pre-arrival, arrival, occupancy, and departure. It describes front office recordkeeping systems and documents. It also outlines the functions of the front desk and the hotel's telecommunications systems. Finally, it identifies common property management systems used in hotel front offices to support operations.
This document outlines plans to upgrade an existing brake system for an FSAE race car to be 15% lighter, more compact, and higher performing. It discusses analyzing the current system, brainstorming concepts including a 2-piston and 4-piston caliper design, and selecting a final design of a rigid 2-piston caliper machined from billet aluminum to interface with other vehicle components. The project will apply knowledge from previous designs, utilize 5-axis CNC machining, and consider braking balance and vehicle setup through analysis and testing.
Ini Dia 10 Ciri Hubungan Moms dengan Si Kecil yang Goals Banget!Caroline Winata
Pemerintah mengumumkan rencana untuk membangun pusat perbelanjaan baru di pusat kota untuk mendukung pertumbuhan ekonomi. Rencana ini mendapat dukungan dari kalangan bisnis tetapi ditentang oleh kelompok lingkungan karena khawatir akan mengganggu ekosistem setempat. Perdebatan masih berlanjut mengenai dampak sosial ekonomi dan lingkungan dari rencana pembangunan tersebut.
The document summarizes key aspects of the periodic table. It describes how the periodic table is organized into horizontal rows called periods and vertical columns called families or groups. Elements within the same group have similar physical and chemical properties. Metals are found on the left and center of the periodic table and have properties like conductivity and malleability. Non-metals are on the right and have varying properties, often gaining electrons in reactions. Metalloids between metals and non-metals have intermediate properties. Different families like alkali metals, halogens, and noble gases are also described in terms of their physical properties and reactivity.
El documento resume los principales puntos de la Constitución de Ecuador y el Código del Trabajo relacionados con el trabajo. Establece que todos tienen derecho a trabajar libremente y a formas alternativas de resolución de conflictos. Reconoce el voluntariado y estipula que el trabajo debe ser remunerado, salvo casos excepcionales. Detalla requisitos de contratos laborales como duración mínima, jornada máxima, vacaciones anuales y responsabilidad de empleadores.
Genge, kerr assessing the effects of climate change on buildings using the pi...Gerald R. (Jerry) Genge
The Canadian Public Infrastructure Engineering Vulnerability Committee Climate Change Assessment protocol was applied to an existing 40+-year old residential apartment in Toronto. Key findings included a need to respond to Climate Change by altering the design parameters for buildings being designed today to be better able to respond and to improve predictive models.
This document summarizes the credentials and roof coating products of Neogard, a leading producer of elastomeric coating membranes. Neogard has over 45 years of experience innovating polymeric coating technologies. Their fluid-applied roof coating systems form seamless, cool roof membranes for low-slope roofs. These coatings improve energy efficiency by reflecting sunlight, helping to lower building temperatures and cooling costs. Neogard coatings can extend the life of existing roofing materials, reducing waste and costs compared to replacement.
In this time of rising temperatures, abundant rain and socioeconomic imbalance, this seminar will suggest that green roofs are a powerful green building Best Management Practices (BMPs).
This presentation will outline the application, feasibility, benefits and challenges of green roofs in commercial application and put several widely debated questions into perspective: modular trays v. contiguous installations, upfront cost v. long-term investment, green roof v. other options, public access v. limited access, etc. Using local, national and international examples, she will explore green roof issues re: longevity, energy savings, stormwater management, maintenance, incentives and LEED points.
The three learning objectives are a) to understand green roof ROI for commercial buildings, b) to compare stormwater strategies of green roofs v underground cisterns and porous pavers and c) to compare green roofs to a solar roof or a white reflective roof.
Green roofs are a means to lowering the overall ambient temperature, reducing longterm costs on our buildings, sequestering CO2 and producing O2, improving the quality of life in our cities and boosting our green economy. Come learn more about green roofs at this seminar on May 7th.
Create Cool Green Cities! Combat Global Warming!
Contribute for Climate Change issues!
Reduce Energy Consumption in Buildings!
Have Energy Efficient Buildings!
Reduce our City Temp by 2-30C!
Can We Make Life of Common Man Comfortable!
2012 09 - eeba nahbrcip-prod_bldr struct designAmber Joan Wood
This document summarizes a presentation on energy efficient structural design and framing systems. It discusses advanced framing techniques like insulated 3-stud corners, rim headers, continuous drywall, and modular fireplaces that can improve a home's energy efficiency. It provides examples of how these techniques were implemented in test homes and reduced energy use by 30-50% according to modeling and monitoring results. Quality assurance measures like inspection, testing and retesting helped achieve low air infiltration rates below 2 ACH50 in one of the test homes.
The document discusses the features and benefits of replacement windows from a home improvement company. It provides details on licenses, insurance, successful past projects, dealer criteria, questions to ask dealers, and factors homeowners consider like energy efficiency, maintenance, appearance, security, and sound reduction. It also summarizes the company's history and highlights their technology, glass packages, and window performance benefits.
This document provides an outline for a seminar on window detailing. It discusses various window frame materials, functions of glazing, interactions between windows and building components, and terminology related to window performance. It also outlines objectives for detailing windows to address fire safety, water resistance, air and vapor infiltration, structural stability, cost, schedule, and code requirements.
Rainscreen Cladding Summit – December 3rd & 4th, 2018ROCKWOOL
ROCKWOOL™ provided event at the Marshall County Facility and The Peabody Memphis; hosted by Todd Kimmel along with Keith P. Nelson and presented by ROCKWOOL™.
he ROCKWOOL™ provided event at the Marshall County Facility and The Peabody Memphis; hosted by Todd Kimmel along with Keith P. Nelson and presented by ROCKWOOL™.
Thank you for your attendance, participation, and discussions, at the Cladding Summit. We sincerely hope that you found the presentations informative and engaging.
ROCKWOOL is committed to the continued development of high value educational presentations and seminars. Your thoughts and feedback will help to improve our efforts to deliver more value for you and future participants.
ERSystems is a company based in Rockford, MN that specializes in cool roof restoration and reflective roof coatings. They work with 18 employees and aim to expand to 21 employees by the end of the year. ERSystems restored about 36 million square feet of roof in 2007 and is a leader in the reflective roofing industry. Their vision is to develop roofs that last 2-4 times longer than uncoated roofs and minimize environmental impact through the use of coatings and regular maintenance.
Do it-yourself energy efficient projectsAdriana Galue
This document discusses steps to improve home energy efficiency. The biggest energy consumers are space heating, appliances/lighting, and water heating. An energy audit identifies energy losses from conduction, convection, and framing/windows. The first step is an audit to find waste and recommend retrofits. The second step is weatherizing by sealing leaks around windows, doors, outlets and ducts. The third step is proper insulation of attics, walls, floors, and foundations. The fourth step is improving windows. The fifth step covers appliances, lighting, ventilation, and reducing phantom loads. Improving efficiency through simple projects provides great savings.
Energy efficient construction and trainig practices - 1 BasicsMotiva
Best Energy Efficient Construction and Training Practices - 1 Basics
Material is primarily intended for further-education purposes for professional workers. Material can be used in teaching in classroom or self-study.
Teachers and students can use the power point material as a whole or they can pick up the most useful parts.
Including: Energy and moisture of building site, Construction site heating, U-value, Air humidity and condensation point, Drying,and Ventilation.
Co-funded by the intelligent Energy Europe Programme of the European Union. The sole responsibility for the content of this publication lies with the authors. It does not necessarily reflect the opinion of the European Union. Neither the EASME nor the European Commission are responsible for any use that may be made of the information contained therein.
The good practices and principles required for the energy efficient building have been included in the teaching material. The writers are not responsible for their suitability to individual building projects as such. The individual building projects have to be made according to the building design of the targets in question
The document contains plans, diagrams and technical specifications for a multi-level building project. Key elements include moveable louvers on the east and west sides to control sunlight, a photovoltaic solar panel system, water tanks for rain and grey water collection, and trombe walls to passively heat and cool interior spaces. Sustainable materials like recycled plastic, timber and concrete are specified. Diagrams show the building's water, solar and structural systems. Renderings depict the exterior design and landscaped rooftop.
To save energy seal ducts. New code requirements will test ducts for air leakage. Find out the best way to seal your HVAC system whether it's a retrofit or a new system.
This document proposes modifying California's Title 24 building energy efficiency standards to include cool roofs as a prescriptive requirement for nonresidential buildings with low-sloped roofs. Cool roofs have high solar reflectance and thermal emittance, which helps reduce cooling energy usage and peak electricity demand. The proposal recommends establishing minimum solar reflectance requirements for roofs in each climate zone based on life cycle cost analysis showing savings. It outlines changes to the prescriptive, performance, and overall envelope compliance options to incorporate these requirements. Cool roof technologies are widely available for most low-sloped roofing materials at low additional cost.
The popularity of LED and other innovative technologies for outdoor luminaires is driven by today’s focus on cost savings, energy savings and environmental sustainability. But if the outdoor luminaire fails prematurely, the costs of repair or replacement quickly offset any savings or other benefits that might have been realised.
Multiple studies have shown that the root cause of premature failure in outdoor luminaires can often be traced to a failure to equalize pressures within the luminaire’s housing.
Susan presented findings from a comparative study of vented and non-vented LED Roadway Streetlight housings. She discussed how luminaire longevity can be affected by the formation of condensation, the diffusion process, and the impact of factors such as temperature. As this study demonstrates, pressure differentials can compromise housing seals and joints, as well as other connection points within the LED lamp itself – which can reduce the longevity of the power-supply drivers and other electronics. Additional data, from a lifetime study of Protective Vents in outdoor enclosures, will further substantiate the benefits of venting enclosures to prevent premature failure of the sensitive electronics within.
Talk by Susan Chambers, W.L. Gore & Associates (UK) Ltd
Thermal bridging can greatly impact the thermal performance of building envelopes. This presentation discusses research from ASHRAE RP-1365 that quantified thermal bridging in common construction details using 3D modeling. It found that accounting for thermal bridges can decrease a wall's effective R-value by over 30%. The presentation also showed that improving details like slab edges and balcony connections through methods like insulation and thermal breaks provided significant energy savings compared to simply adding clear wall insulation. Overall, the research demonstrates the importance of considering thermal bridging when assessing building envelope performance and codes.
The document provides information for homeowners considering replacing their windows, including dealer criteria, questions to ask dealers, factors to consider in new windows, and information about window performance. It emphasizes the importance of energy efficiency, maintenance-free design, easy cleaning and operation, and lifetime warranties when selecting a replacement window provider.
Panache Green tech Solutions Pvt. Ltd. ( PGTS) takes the privilege to introduce itself as pioneers in providing Energy Efficient Building Enveloping with its range of innovative products, systems & to deliver the Concept of “Cool Homes without AC!”
Panache started its journey in 2008 as Aesthetic Solutions and in a short span of 6 years it has a wide spectrum clientele of Platinum , Gold LEED rated buildings ,Commercial , Residential and Industrial projects.
Panache with the conscious efforts to promote environment friendly approach , comprises a complete product range of water based products & excels to innovate in sustainable designs , products & systems for various applications.
Please visit:- www.panachegreen.com
Follow our Facebook Page by liking the link
https://www.facebook.com/panachegreen.pgtech
Follow us on twitter
https://twitter.com/PanacheGTech
http://panachegreen.blogspot.in/
Thermal insulation provides several key benefits for buildings located in tropical countries. It creates an insulated envelope that stops heat and cold from transferring into or out of the building. This maintains interior temperatures for longer periods and improves human comfort while reducing energy costs. The document discusses the necessity of insulation, design considerations, common application methods, and case studies. It also covers the Energy Conservation Building Code which determines minimum insulation thickness requirements. External insulation on roofs and walls is most effective at stopping heat at its source, while internal insulation provides faster cooling for individual rooms.
Advanced control scheme of doubly fed induction generator for wind turbine us...IJECEIAES
This paper describes a speed control device for generating electrical energy on an electricity network based on the doubly fed induction generator (DFIG) used for wind power conversion systems. At first, a double-fed induction generator model was constructed. A control law is formulated to govern the flow of energy between the stator of a DFIG and the energy network using three types of controllers: proportional integral (PI), sliding mode controller (SMC) and second order sliding mode controller (SOSMC). Their different results in terms of power reference tracking, reaction to unexpected speed fluctuations, sensitivity to perturbations, and resilience against machine parameter alterations are compared. MATLAB/Simulink was used to conduct the simulations for the preceding study. Multiple simulations have shown very satisfying results, and the investigations demonstrate the efficacy and power-enhancing capabilities of the suggested control system.
Harnessing WebAssembly for Real-time Stateless Streaming PipelinesChristina Lin
Traditionally, dealing with real-time data pipelines has involved significant overhead, even for straightforward tasks like data transformation or masking. However, in this talk, we’ll venture into the dynamic realm of WebAssembly (WASM) and discover how it can revolutionize the creation of stateless streaming pipelines within a Kafka (Redpanda) broker. These pipelines are adept at managing low-latency, high-data-volume scenarios.
A review on techniques and modelling methodologies used for checking electrom...nooriasukmaningtyas
The proper function of the integrated circuit (IC) in an inhibiting electromagnetic environment has always been a serious concern throughout the decades of revolution in the world of electronics, from disjunct devices to today’s integrated circuit technology, where billions of transistors are combined on a single chip. The automotive industry and smart vehicles in particular, are confronting design issues such as being prone to electromagnetic interference (EMI). Electronic control devices calculate incorrect outputs because of EMI and sensors give misleading values which can prove fatal in case of automotives. In this paper, the authors have non exhaustively tried to review research work concerned with the investigation of EMI in ICs and prediction of this EMI using various modelling methodologies and measurement setups.
KuberTENes Birthday Bash Guadalajara - K8sGPT first impressionsVictor Morales
K8sGPT is a tool that analyzes and diagnoses Kubernetes clusters. This presentation was used to share the requirements and dependencies to deploy K8sGPT in a local environment.
Electric vehicle and photovoltaic advanced roles in enhancing the financial p...IJECEIAES
Climate change's impact on the planet forced the United Nations and governments to promote green energies and electric transportation. The deployments of photovoltaic (PV) and electric vehicle (EV) systems gained stronger momentum due to their numerous advantages over fossil fuel types. The advantages go beyond sustainability to reach financial support and stability. The work in this paper introduces the hybrid system between PV and EV to support industrial and commercial plants. This paper covers the theoretical framework of the proposed hybrid system including the required equation to complete the cost analysis when PV and EV are present. In addition, the proposed design diagram which sets the priorities and requirements of the system is presented. The proposed approach allows setup to advance their power stability, especially during power outages. The presented information supports researchers and plant owners to complete the necessary analysis while promoting the deployment of clean energy. The result of a case study that represents a dairy milk farmer supports the theoretical works and highlights its advanced benefits to existing plants. The short return on investment of the proposed approach supports the paper's novelty approach for the sustainable electrical system. In addition, the proposed system allows for an isolated power setup without the need for a transmission line which enhances the safety of the electrical network
TIME DIVISION MULTIPLEXING TECHNIQUE FOR COMMUNICATION SYSTEMHODECEDSIET
Time Division Multiplexing (TDM) is a method of transmitting multiple signals over a single communication channel by dividing the signal into many segments, each having a very short duration of time. These time slots are then allocated to different data streams, allowing multiple signals to share the same transmission medium efficiently. TDM is widely used in telecommunications and data communication systems.
### How TDM Works
1. **Time Slots Allocation**: The core principle of TDM is to assign distinct time slots to each signal. During each time slot, the respective signal is transmitted, and then the process repeats cyclically. For example, if there are four signals to be transmitted, the TDM cycle will divide time into four slots, each assigned to one signal.
2. **Synchronization**: Synchronization is crucial in TDM systems to ensure that the signals are correctly aligned with their respective time slots. Both the transmitter and receiver must be synchronized to avoid any overlap or loss of data. This synchronization is typically maintained by a clock signal that ensures time slots are accurately aligned.
3. **Frame Structure**: TDM data is organized into frames, where each frame consists of a set of time slots. Each frame is repeated at regular intervals, ensuring continuous transmission of data streams. The frame structure helps in managing the data streams and maintaining the synchronization between the transmitter and receiver.
4. **Multiplexer and Demultiplexer**: At the transmitting end, a multiplexer combines multiple input signals into a single composite signal by assigning each signal to a specific time slot. At the receiving end, a demultiplexer separates the composite signal back into individual signals based on their respective time slots.
### Types of TDM
1. **Synchronous TDM**: In synchronous TDM, time slots are pre-assigned to each signal, regardless of whether the signal has data to transmit or not. This can lead to inefficiencies if some time slots remain empty due to the absence of data.
2. **Asynchronous TDM (or Statistical TDM)**: Asynchronous TDM addresses the inefficiencies of synchronous TDM by allocating time slots dynamically based on the presence of data. Time slots are assigned only when there is data to transmit, which optimizes the use of the communication channel.
### Applications of TDM
- **Telecommunications**: TDM is extensively used in telecommunication systems, such as in T1 and E1 lines, where multiple telephone calls are transmitted over a single line by assigning each call to a specific time slot.
- **Digital Audio and Video Broadcasting**: TDM is used in broadcasting systems to transmit multiple audio or video streams over a single channel, ensuring efficient use of bandwidth.
- **Computer Networks**: TDM is used in network protocols and systems to manage the transmission of data from multiple sources over a single network medium.
### Advantages of TDM
- **Efficient Use of Bandwidth**: TDM all
A SYSTEMATIC RISK ASSESSMENT APPROACH FOR SECURING THE SMART IRRIGATION SYSTEMSIJNSA Journal
The smart irrigation system represents an innovative approach to optimize water usage in agricultural and landscaping practices. The integration of cutting-edge technologies, including sensors, actuators, and data analysis, empowers this system to provide accurate monitoring and control of irrigation processes by leveraging real-time environmental conditions. The main objective of a smart irrigation system is to optimize water efficiency, minimize expenses, and foster the adoption of sustainable water management methods. This paper conducts a systematic risk assessment by exploring the key components/assets and their functionalities in the smart irrigation system. The crucial role of sensors in gathering data on soil moisture, weather patterns, and plant well-being is emphasized in this system. These sensors enable intelligent decision-making in irrigation scheduling and water distribution, leading to enhanced water efficiency and sustainable water management practices. Actuators enable automated control of irrigation devices, ensuring precise and targeted water delivery to plants. Additionally, the paper addresses the potential threat and vulnerabilities associated with smart irrigation systems. It discusses limitations of the system, such as power constraints and computational capabilities, and calculates the potential security risks. The paper suggests possible risk treatment methods for effective secure system operation. In conclusion, the paper emphasizes the significant benefits of implementing smart irrigation systems, including improved water conservation, increased crop yield, and reduced environmental impact. Additionally, based on the security analysis conducted, the paper recommends the implementation of countermeasures and security approaches to address vulnerabilities and ensure the integrity and reliability of the system. By incorporating these measures, smart irrigation technology can revolutionize water management practices in agriculture, promoting sustainability, resource efficiency, and safeguarding against potential security threats.
ACEP Magazine edition 4th launched on 05.06.2024Rahul
This document provides information about the third edition of the magazine "Sthapatya" published by the Association of Civil Engineers (Practicing) Aurangabad. It includes messages from current and past presidents of ACEP, memories and photos from past ACEP events, information on life time achievement awards given by ACEP, and a technical article on concrete maintenance, repairs and strengthening. The document highlights activities of ACEP and provides a technical educational article for members.
Literature Review Basics and Understanding Reference Management.pptxDr Ramhari Poudyal
Three-day training on academic research focuses on analytical tools at United Technical College, supported by the University Grant Commission, Nepal. 24-26 May 2024
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Factors Affecting Moisture Problems in Attics
What influences attic moisture issues &
what can we control by design?
Roof orientation (solar radiation)
Roof slope (solar radiation)
Roofing material/color
Adjacent buildings – shading
Trees – shading & debris
Outdoor climate
Indoor climate
Roof Leaks
Insulation R-value
Air leakage from house
Duct leakage in attic
Duct discharge location
Vent area and distribution
Sheathing durability
Roof maintenance
Other things…
6. 6 of 85
Where are we Seeing the Biggest Issues?
1. Air leakage (ceiling details)
2. Exhaust duct leaks & discharge location (roof, soffit, or wall)
3. Inadequate venting provisions (amount, vent location, or materials)
4. Outdoor moisture: night sky condensation on underside of sheathing
5. Wetting through shingles/roofing (tipping the moisture balance)
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The Localized Nature of Air Leakage Condensation
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Standard Faith-Based Air-Sealing Approach
Air-sealing details, duct exhaust
details often not provided & left
up to the contractor
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The Localized Nature of Leaking Penetrations
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Typical Issues – Impact of Orientation
South Facing
North Facing
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Typical Issues – Impact of Orientation
North =
Soaked
South (Partially
Shaded) = Damp
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Case Study: Two Steps Forward, One Step Backwards
2007 investigation of 5 year old large townhouse complex
Was experiencing many of the typical attic problems
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An Assortment of Issues – Exhaust Duct Details
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An Assortment of Issues – Exhaust Duct Details
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An Assortment of Issues – Inadequate Ridge ‘Vent’ Material
Almost no effective net
free area, 5 layers of filter
fabric
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An Assortment of Issues – Ceiling Air Leakage
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But we know how to solve these problems...
Guide to Best Practices for Air Sealing and
Insulation Retrofits - Produced by RDH and published
by BC Housing
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Key Findings from Field Investigations
Seeing widespread issues with
mold growth in wood-frame attics in
Coastal Pacific Northwest in past
decade
Wetting exceeding drying capacity
provided by ventilation
Problem is most often NOT due to
a lack of ventilation
Usual culprits of air-leakage
condensation (leaky ceiling, leaky
ducts & discharge point)
Also seeing supplemental exterior
moisture sources (night sky
condensation, rainwater seepage)
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Industry Trends – Less Heat Flow into Attic Spaces
<1970’s attic construction with
excessive air leakage and heat loss
into the attic
1980’s to 1990’s attic construction with
moderate air leakage and heat loss into
the attic
2000’s attic construction with minimal air
leakage and heat loss into the attic
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Research Study
Controlled field monitoring study
to isolate exterior wetting
mechanisms from interior
sources (air, vapour)
To specifically evaluate impact of
orientation, slope (3:12, 4:12 and
6:12) & shingle underlay
Remove influence of air leakage
or heat gain from house
Monitor the performance of
surface treatments Theoretical attic with no air
leakage or heat loss into
the attic and unrestricted
ventilation
(Arrangement for Study)
Typical ventilated attic
construction with air
leakage and heat loss into
the attic
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Roof Test Hut Field Monitoring Setup
a) 3:12 Slope roof with roofing felt underlay b) 4:12 Slope roof with roofing felt underlay
c) 6:12 Slope roof with roofing felt underlay d) 3:12 Control roof with SAM underlay
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Monitoring Equipment & Sensors
Moisture Content, Temperature, Relative
Humidity and surface Condensation sensors –
north and south slopes x 4 huts
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Results - Seasonal Averages
0
5
10
15
20
25
30
Fall 2012 Winter
2012/2013
Spring 2013 Summer
2013
Fall 2013 Winter
2013/2014
Spring 2014
MoistureContent(%)
MC-FULL-N-CONT MC-FULL-S-CONT MC-FULL-N-312 MC-FULL-S-312
MC-FULL-N-412 MC-FULL-S-412 MC-FULL-N-612 MC-FULL-S-612
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Long-Term Impacts of Elevated Moisture Contents
North 3:12 after 1 year North 4:12 after 1 year
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Tracking Mold Growth
TABLE 2: VITTANEN’S MOLD GROWTH INDEX DESCRIPTIONS
INDEX GROWTH RATE DESCRIPTION
0 No growth Spores not activated
1 Small amounts of mold on surface (microscope) Initial stages of growth
2 <10% coverage of mold on surface (microscope) ___
3 10% – 30% coverage of mold on surface (visual) New spores produced
4 30% – 70% coverage of mold on surface (visual) Moderate growth
5 >70% coverage of mold on surface (visual) Plenty of growth
6 Very heavy and tight growth Coverage around 100%
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Why is the Sheathing Wet? What is the Mechanism?
Night sky condensation!
(Important: It happen when all moisture sources eliminated.)
Radiative heat loss from roof surface
to colder night sky
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When Does it Occur?
0
100
200
Oct 02 Oct 03 Oct 04 Oct 05 Oct 06
S
Solar Radiation CONDENSE-Plywood-312
Increa
0
5
10
15
20
25
30
Oct 02 Oct 03 Oct 04 Oct 05 Oct 06
MoistureContent[%]andTemperature[°C]
Condensation
0
5
10
15
20
25
30
Oct 02 Oct 03 Oct 04 Oct 05 Oct 06
MoistureContent[%]andTemperature[°C]
MC-FULL-N-312 MC-IN-SURF-N-312 T-IN-N-312-Plywood
T-N-312-Embedded Outdoor - Temperature Outdoor - Dewpoint
COND-N-312 Sheathing Solar Radiation
Condensation
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When Does it Occur?
0
100
200
300
400
Oct 02 Oct 03 Oct 04 Oct 05 Oct 06
SolarR
Solar Radiation CONDENSE-Plywood-312
IncreasingSu
0
5
10
15
20
25
30
Oct 02 Oct 03 Oct 04 Oct 05 Oct 06
MoistureContent[%]andTemperature[°C]
Condensation
0
5
10
15
20
25
30
Oct 02 Oct 03 Oct 04 Oct 05 Oct 06
MoistureContent[%]andTemperature[°C]
MC-FULL-N-312 MC-IN-SURF-N-312 T-IN-N-312-Plywood
T-N-312-Embedded Outdoor - Temperature Outdoor - Dewpoint
COND-N-312 Sheathing Solar Radiation
Condensation
0
100
200
300
400
500
600
700
800
900
1000
Oct 02 Oct 03 Oct 04 Oct 05 Oct 06
SolarRadiation[W/m2]
Solar Radiation CONDENSE-Plywood-312
IncreasingSurfaceCondensation
20
25
30
mperature[°C]
20
25
30
emperature[°C]
0
100
200
Oct 02 Oct 03 Oct 04 Oct 05 Oct 06
Solar Radiation CONDENSE-Plywood-312
Inc
0
5
10
15
20
25
30
Oct 02 Oct 03 Oct 04 Oct 05 Oct 06
MoistureContent[%]andTemperature[°C]
Condensation
0
5
10
15
20
25
30
Oct 02 Oct 03 Oct 04 Oct 05 Oct 06
MoistureContent[%]andTemperature[°C]
MC-FULL-N-312 MC-IN-SURF-N-312 T-IN-N-312-Plywood
T-N-312-Embedded Outdoor - Temperature Outdoor - Dewpoint
COND-N-312 Sheathing Solar Radiation
Condensation
Heavy Condensation
Daily Solar Radiation
Cycles
Dry
Light Condensation
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Shingle & Sheathing Temperature Depressions
2.6 2.5 2.5
2.6
2.4 2.5
0.9 0.9 0.9 1.0 1.0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
312-N 312-S 412-N* 412-S 612-N 612-S
TemperatureDepressionfromAmbient
(°C)
Avg Shingle T Avg Interior Sheathing Surface T
*412-N sheathing temperature unavailable due to sensor malfunction
Average Shingle and Sheathing Temperature Depression compared to
Ambient Temperature for Winter
(December 1, 2013 to January 31, 2014).
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Hours of Potential Condensation - Sheathing
0
100
200
300
400
500
600
700
800
0.00
0.25
0.50
0.75
1.00
1.25
1.50
North South
HoursofPotentialCondensation
TemperatueDepressionfromAmbient(°C)
3:12 Temp 4:12 Temp 6:12 Temp 3:12 Hours 4:12 Hours 6:12 Hours
150 to 300 hours per year
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On the Flip Side: Solar Heat Gain & Drying During the Day
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On the Flip Side: Solar Heat Gain & Drying Potential
0
5
10
15
20
25
30
35
40
45
50
55
60
Aug 21 00:00 Aug 21 06:00 Aug 21 12:00 Aug 21 18:00 Aug 22 00:00
Temperature[°C]
Temperatures - 3:12 and 6:12 Slope Roofs - Early Spring Conditions
T-OUT-N-612-Shingle
T-OUT-S-612-Shingle
T-IN-N-612-Plywood
T-IN-S-612-Plywood
T-OUT-N-312-Shingle
T-OUT-S-312-Shingle
T-IN-N-312-Plywood
T-IN-S-312-Plywood
Outdoor - Dewpoint
Outdoor - Temperature
South Shingles 55°C
North Shingles
35-40°C
South Sheathing = 35°C
North Sheathing = 31°C
Ambient
Air up to
21°C
Lots of cloud cover changes the wetting and drying balance.
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A Localized Problem...
Seattle
Portland
Vancouver
San Francisco
Calgary
High Risk Climate for
Night Sky Radiation Attic
Moisture Issues
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Key Findings – The Cause of the Pacific Northwest Problems
Roof sheathing in well ventilated attics (also soffits, canopies) experiences elevated
moisture levels in winter
Occurs despite elimination of typical wetting mechanisms within attics (air
leakage, duct leakage, rain water leaks etc.)
Moisture level is above equilibrium level indicating additional wetting sources
Night sky cooling causes wetting when sheathing drops below ambient dewpoint (few
hundred hours per year) in attic
Difficult to stop it from occurring
Fungal growth occurs due to elevated moisture content and condensation on
underside of sheathing
More fungal growth on north than south – drying matters, the heat from a ceiling
above a house will help too
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Monitoring of Potential Mitigation Strategies
Vented underlayment to
de-couple night sky radiation
cooling effects
Surface treatments to kill &
prevent fungal growth
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Vented Underlay - Night Sky Radiation De-Coupler?
Vented shingle underlay
installed in one roof in 2nd
year of study
Purpose: try to de-couple
night sky cooling effects from
sheathing
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Vented Underlay – The Double Edged Sword
South Orientation – Vented Underlay vs Direct Applied Shingles
0
50
100
150
200
250
300
350
400
450
-5
0
5
10
15
20
25
Jan 16 Jan 17 Jan 18
SolarRadiation(W/m2)
Temperature(°C)
T-OUT-S-VENT (Shingles) T-IN-S-VENT (Sheathing)
T-OUT-S-312 (Shingles) T-IN-S-312 (Sheathing)
Outdoor T T-Drainmat-S-VENT
Solar Radiation
Shingles – direct applied
Shingles – vent mat
6°C drop in
shingle
1°C drop in
sheathing
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Vented Underlay – The Double Edged Sword
0
2
4
6
8
10
12
14
16
6
8
10
12
14
16
18
20
22
Day Night Avg
Temperature(°C)
MoistureContent(%)
Spring
VENT-N-MC VENT-S-MC 312-N-MC 312-S-MC
VENT-N-T VENT-S-T 312-N-T 312-S-T
North
South
North
South
Vent Normal
Spring (March 1, 2013 to April 30, 2013) Diurnal Moisture Content (SURF) and Temperature
Averages for North and South Oriented Vented and Control (Direct Applied Shingles) Roof
Assemblies
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Visual Assessment of Surface Treatment Efficacy
VISUAL ASSESSMENT OF SURFACE TREATMENT EFFICACY
Test
Roof
Surface Treatments (north left, south right)
Sansin
Boracol®
20-2
Copper
Naphthenate
Bleach
Thompsons
WaterSeal®
Kilz®Paint
Zinc
Naphthenate
Sansin
Boracol®
20-2BD
Control
3:12
4:12
6:12
VISUAL ASSESSMENT SCALE
Pristine or very light fungal growth
Moderate fungal growth
Significant fungal growth
In our experience Kilz® & Boracol® 20-
2BD while okay here after 2 years may
not be best long term for fungal growth
Need duplicate samples – slope not a big factor (heartwood vs
sapwood is)
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Wood Preservative & Fungicide Surface Treatments
The best decay fungicide looked okay in years 1 and
2 – but not in year 3
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Summary – Mitigation Strategy Performance
Thermally de-coupling the exposed shingles from the sheathing did
not work well
Did not significantly increase sheathing temperature at night, but did
reduce drying from solar heat gain
Surface treatments appear to be a potentially viable solution if right
product is developed – currently available products not quite
effective (nor developed specifically for this application)
Concurrent work by FP Innovations to perform accelerated testing of
some new biocides/fungicides
Ongoing monitoring of huts to monitor long-term field performance of
next generation treatments
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Concurrent Fungicide/Biocide Research – FP Innovations
Developed an accelerated 12
week test method to evaluate
new fungicides applied to
wood products
Have already tested a
handful of newly innovated &
proprietary fungicides &
coatings
A few promising formulations
completely prevented mold
growth
Follow-up with field testing
Images courtesy FP Innovations
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Field Trials & Monitoring of 9 New Treatments – Round 2
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Ongoing Monitoring of New Surface Treatments
Most Promising
fungicide/biocide is water
repelling & contains several
“active” ingredients to
prevent long term mold
growth.
Note it is not a wood
preservative it is a fungicide
Currently undergoing
environmental testing &
available soon?
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Final Thoughts
Ventilated attics & roof assemblies ‘built to code’ are experiencing mold
growth on underside of sheathing (plywood or OSB)
Wetting from night sky condensation and may be exacerbated by air
leaks & water leaks
Hard to reliably stop night sky condensation
Ventilation on its own is not a solution
Mold growth may be minor but perceived as risk
Could build other roof assemblies but unlikely to replace ventilated attics
any time soon
Need to address durability & sensitivity of wood based sheathings to mold
growth, various groups are developing products
Just make sure the fungicide is no more harmful to humans than the
mold is…
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Additional Resources
RDH Technical Bulletin No. 10 - Mold in Vented
Wood-Frame Roofs in the Coastal Pacific Northwest
RDH Blog Article – Re-Thinking Ventilated Attics:
How to Stop Mold Growth in Coastal Climates
Why Wood Frame Attics Get Wet & Mouldy in the
Pacific Northwest - Conference Paper at 30th RCI
International Convention & Tradeshow
Guide to Best Practices for Air Sealing and
Insulation Retrofits - Produced by RDH and published
by BC Housing
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FOR FURTHER INFORMATION PLEASE VISIT
www.rdh.com and www.buildingsciencelabs.com
Lorne Ricketts - lricketts@rdh.com
Discussion + Questions