Tag Archives: resources

Future Trends for Architectural Conservation

As part of the sesquicentennial celebration of Canadian Confederation independence, the National Trust for Canada and the Association for Preservation Technology International co-sponsored the largest joint conference of heritage professionals. Over 1,100 attendees from twenty countries attended the week-long event focused both on technical issues and heritage planning.

The shear size of the conference was overwhelming, but the host city, Ottawa, (APTI) was an ideal venue because of its position as the capitol city of Canada, the quantity of heritage resources, including the Rideau Canal World Heritage Site, and beautiful world class museums and parks.

As with all APTI annual conferences, the week begins with two day long workshops highlighting the craft of preservation. This year’s workshops included Logs & Timbers, Masonry Mortars, and Digital Tools for Documentation. Masonry Mortars has been offered several times over the last five years at APTI conferences and is always popular demonstrating the continual need to understand mass masonry walls, their performance, and specialized products and skills required to restore and preserve the walls.
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HOW ROBOTS CAN ASSIST WITH CONSERVATION
National Trust conferences, in both Canada and the United States offer many tours during the course of the conference and one of tours focused on robotics for heritage conservation. A conservation lab at Carlton University, founded after World War II and one of Ottawa’s public universities, has created a curriculum around the use of robotics to enhance the preservation craft of traditional materials. Conference attendees viewed a demonstration of a robotic arm manufactured in Germany, by the supplier of robotic arms to the automotive industry, with a custom built “hand” designed to hold stone cutting tools. As a demonstration, the Carlton University staff carved a block of sandstone scheduled to replace original material on the Canadian parliament buildings as part of a massive restoration effort. The demonstration was fascinating in the speed by which the robot carved the material with fine accuracy. Attendees were interested in the conservation aspect of the robot and asked about the stone cutting techniques and potential replacement of stone carvers.

Since the robot uses circular drill bits as cutting tools resulting in smoother finishes than traditional chisel cutting, some attendees were skeptical of the robot as a tool for capturing traditional stone techniques. As to the replacement of stone carvers, the response was straight forward: there are fewer and fewer trades personnel that know how to carve stone. The robot is envisioned as a method to allow traditional stone decoration to return to modern design.
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With seven separate tracks of Paper Sessions, it was impossible to take in the full offerings of the joint conference. The use of robots, technology, and computer software simulations continued throughout some of tracks of the Paper Sessions. Particularly interesting was hearing from archeologists in Italy and Chile that, unlike US archeologists, are involved in the documentation, history, and preservation of building materials. Using traditional archeological approaches to documentation and recordation, the archeologists combined their research, historic photographs, current images, on-site destructive testing in unique ways of explaining the chronology of construction and materials used.

Demonstrating the continued convergence of building envelop science with preservation science, many Paper Sessions focused on windows, energy retrofits, and the need to develop better science and research of traditional construction means and methods. One session on mass masonry walls hypothesized that mass masonry walls have a temperature ductility allowing them to expand during cold wet weather in order to accommodate the stress induced by freezing temperatures. One early study in the 1960’s documented the phenomena but without sufficient repeated testing. The engineer making the presentation asked for all those in the audience to create an accessible database of masonry performance in order to expand the collective knowledge base.
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THE FUTURE OF PRESERVATION LOOKS MODERN
One of the plenary speakers called on heritage preservation to continue leadership in the adaptive reuse of existing buildings, specifically mid-century modern structures, because of the huge environmental impact conservation efforts will have on global warming, waste reduction, and heritage values.

Attendance at APTI national conferences are a great way to gain new knowledge, converse with professional peers, anticipate future trends, evaluate current business practices, and interact outside day to day professional demands.

Written by Peter Meijer, AIA, NCARB / Principal

Analysis: Best Practices for Providing Effective Daylight in Mid-Century Modern Structures

DOCOMOMO_OREGON and the Northwest Chapter of the Association for Preservation Technology recently held an Energy Conservation Symposium that explored issues facing mid-century modern buildings: How can modern historic buildings comply with today’s energy conservation standards? Is it possible to maintain the integrity of the historic building materials and aesthetics while also meeting new energy conservation requirements?

At PMA we believe that while challenging, it is possible to maintain the integrity of these historic mid-century modern buildings and meet new energy conservation requirements. In an effort to explore this possibility, we submitted an abstract for the symposium, and Halla Hoffer, AIA, subsequently presented on Best Practices for Providing Effective Daylight in Mid-Century Modern Structures.

BACKGROUND
Effective daylighting can reduce both lighting and cooling loads while improving user comfort, satisfaction, and health. Despite plentiful glass, using daylight in mid-century modern building can be challenging. Glare and uneven light distribution can cause user discomfort and pose challenges to effectively daylighting spaces. Frequently, artificial lighting is used to balance lighting in spaces over lit by the sun, negating any potential energy savings. For existing buildings, the available methods to provide effective daylighting are limited by the existing constructions and configuration. To both preserve existing structures and provide ample daylight a critical question must be answered – what are the best practices for improving daylight in existing buildings? This study provides insight to daylighting existing structures, specifically, how light can be controlled and distributed in mid-century modern buildings with plentiful glazing.

1963 RESIDENTIAL TOWER
This study explores and analyzes how common daylighting strategies can be implemented on existing mid-century modern structures. The study focuses on a sixteen-story 1963 residential tower in Portland, Oregon, and explores how interior reflectivity, interior/exterior light shelves, shading, and glazing can impact daylight availability and distribution. The study looks at a variety of ways each strategy can be implemented and analyzes the results to determine best practices based on daylight distribution/availability, glare, lighting loads, and heating/cooling loads.
on Best Practices for Providing Effective Daylight in Mid-Century Modern Structures

TOOLS USED FOR SPECIFIC ANALYSIS
Emerging tools and technologies provide effective methods of analyzing hundreds of different daylighting simulations. Applications such as Grasshopper and Dynamo, which are visual programming environments for Rhinoceros 3D and Revit respectively, allow users to explore a variety of different design interventions and determine optimal solutions. Prior to starting the daylight analysis, we began with a “base geometry” of the existing conditions that we modeled in Rhinoceros 3D. We then developed a Grasshopper file to create daylighting interventions. For this study the interventions consisted of interior light shelves and exterior shading devices based on numerical inputs for shelf depth and height. Using Grasshopper in lieu of traditional 3D modeling allowed us to systematically test multiple variations of intervention geometry. In addition to studying how new geometries would impact daylighting we also studied how existing/new materials could impact daylighting performance.
on Best Practices for Providing Effective Daylight in Mid-Century Modern Structures

The daylighting analysis was performed using DIVA for Rhino, a plug-in that performs daylighting and energy analysis directly in Rhino. DIVA also offers several Grasshopper nodes, allowing the analysis to be controlled and managed directly in Grasshopper. For this analysis the primary results we extracted and used to measure performance included:

Annual Daylight: Percentage of time space receives at least 300 lux. This value can be mapped over the area under analysis. Typically, areas that receive 300 lux at least 50% of the time have the potential for daylighting.

Spatial Daylight Autonomy (sDA): Percentage of a space that receives 300 lux for at least 50% of the annual occupied hours. This metric provides a single number for quickly determining daylight potential. A value over 55 indicates that daylighting will be at a minimum nominally accepted by occupants. A value over 75 denotes a space where daylighting will likely be preferred by occupants.

Annual Sunlight Exposure (ASE): Percentage of a space that receives over 1,000 lux for at least 250 hours per year. High values indicate that the space may be overlit and cause glare/discomfort.

Daylight Factor: A ratio comparing light levels on the interior of the structure to the light levels on the exterior. Typically, a value under 2% indicates that the space cannot be adequately daylit, a value between 2%-5% is preferred for daylighting, and a value over 5% indicates that the space is well daylight, but may be overlit.

on Best Practices for Providing Effective Daylight in Mid-Century Modern Structures

CONCLUSIONS
Reflective interior surfaces can have a significant impact on daylight distribution.

Without any shading there is a high probability for glare according to ASE and DF values.

Interior light shelves alone can reduce the ASE values and the probability of glare.

Interior light shelves alone are not as effective as exterior shading devices in reducing glare.

A combination of reflective interior materials, interior light shelves, and exterior shading devices is the most effective method to provide adequate levels and even distribution of light.

Written and presented by Halla Hoffer, AIA, Assoc. DBIA / Associate

Abstract: Best Practices for Providing Effective Daylight in Mid-Century Modern Structures

When we think of energy conservation standards for our built environment an increasing amount of existing buildings do not comply with today’s standards. A large portion of these existing buildings are from the mid-century modern era. Additionally, mid-century modern buildings are approaching historic status, if not already there. This status compounds finding the best way to integrate current energy standards because aesthetic impacts to a historic resource must be kept to a minimum. At PMA we believe that while challenging, it is possible to maintain the integrity of historic mid-century modern buildings while meeting new energy conservation requirements. In an effort to explore this possibility, we have submitted an abstract for an upcoming Energy Conservation in Mid-Century Modern Buildings Symposium presented jointly by APT Northwest and DOCOMOMO_Oregon.
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ABSTRACT: BEST PRACTICES FOR PROVIDING EFFECTIVE DAYLIGHT IN MID-CENTURY MODERN STRUCTURES
Effective daylighting can reduce both lighting and cooling loads while improving user comfort, satisfaction, and health. Despite plentiful glass, using daylight in mid-century modern building can be challenging. Glare and uneven light distribution can cause user discomfort and pose challenges to effectively daylighting spaces. Frequently, artificial lighting is used to balance lighting in spaces over lit by the sun, negating any potential energy savings. For existing buildings, the available methods to provide effective daylighting are limited by the existing constructions and configuration. To both preserve existing structures and provide ample daylight a critical question must be answered – what are the best practices for improving daylight in existing buildings? This study provides insight to daylighting existing structures, specifically, how light can be controlled and distributed in mid-century modern buildings with plentiful glazing.

Emerging tools and technologies provide effective methods of analyzing hundreds of different daylighting simulations. Applications such as Grasshopper and Dynamo allow users to explore a variety of different design interventions and determine optimal solutions. This study explores and analyzes how common daylighting strategies can be implemented on existing mid-century modern structures. The study focuses on a 1963 residential tower in Portland, Oregon, and explores how interior reflectivity, interior/exterior light shelves, shading, and glazing can impact daylight availability and distribution. The study looks at a variety of ways each strategy can be implemented and analyzes the results to determine best practices based on daylight distribution/availability, glare, lighting loads, and heating/cooling loads.

Speaker Bio
Halla Hoffer, AIA, Assoc. DBIA
Associate / Peter Meijer Architect, PC

Halla is passionate about rehabilitating historic and existing architecture by integrating the latest energy technologies to maintain the structures inherent sustainability. Halla joined PMA in 2012 and was promoted to Associate in 2016. She is a specialist in energy and environmental management, as well as building science performance for civic, educational, and residential resources. Halla meets the Secretary of the Interior’s Historic Preservation Professional Qualification Standards (36 CFR Part 61).