The Value of Original Window Repair and Retrofit: Studies and Research

The issue of the retention of original windows in preservation, and lately, in sustainability, is of such importancethat it merits its own web page. It is commonly asked where the arguments are to defend original windows, and how to respond to calls forwindow replacement. The perception of preservationists is that there is a large replacement window industry advertising the attractiveness, the no maintenance, and the energy efficiency of a new window, but no one to promote the attractiveness and energy efficiency of a properly maintained original window. Occasional maintenance is required of a historic window; they were built to be reasonably maintained by the owner of the building. New windows are no maintenance because when they break, they have to be replaced. Maintenance is not possible for a modern window.

Lately, new pressure to replace windows is felt from the green products and third party energy certification industries, which emphasize the energy efficiency of new windows and encourage their installation. To their credit, third party certifiers are beginning to acknowledge that repaired windows have equal value to replacement windows in their point rating systems, or are measuring the efficiency of the building envelope as a whole.

Many studies demonstrate the viability of repairing original windows. Some of them are collected here. All of the studies conclude that original window repair and other conservation strategies provide similar energy benefits of a replacement window, with less impact to the environment as an existing resource.

The national Window Preservation Standards book catalogs specific methods for the assessment, maintenance, repair, preservation and weatherization of older and historic wooden windows. Many detailed methods, procedures and materials are included, as well as basic strategies for saving older and historic windows.

Topics include the Window Preservation Standards Collaborative, guiding principles for window preservation work, window part names and definitions, organizing and planning window preservation projects, and how to use the Standards.

Methods include surveying and assessing conditions, glazing, painting, wood repairs, weatherization updates, storm windows and maintenance with many more. Each treatment standard has a brief description of a specific method with appropriate use, a step-by-step procedure that shows what is done and materials are listed. A special section describes how to judge the character of the completed work with easy observations and simple tests to assure the best quality work.

The results of energy performance testing done at the 2011 National Window Preservation Summit are included. It confirms what is already known: Save the primary sash and frame, add weatherstripping and a storm to make the window meet or exceed current performance standards for air infiltration. All the details are in the book, including which energy upgrade methods worked best.

The Window Preservation Standards book is a non-profit project done in partnership with the Preservation Trades Network, Kentucky Heritage Council and Kentucky Preservation. Ordering information can be found here.

A report just produced by the National Trust for Historic Preservation Green Lab provides cost guidance for homeowners weighing the financial and energy tradeoffs between replacing or repairing older, less efficient windows. This report, "Saving Windows, Saving Money: Evaluating the Energy Performance of Window Retrofit and Replacement", builds on previous research by examining multiple window improvement options, comparing them to replacement windows across multiple climate regions.

Saving Windows, Saving Moneys key findings offer homeowners, contractors, architects and others with compelling evidence of the merits of retrofitting windows as opposed to outright replacement.

Key findings include:

Retrofit measures can achieve performance results comparable to new replacement windows. This study shows that there are readily available retrofit measures that can achieve energy savings close to new, high performance replacement windows when the performance for each upgrade option is taken into account.

Almost every retrofit option Offers a better Return on Investment (ROI) than replacement windows. Findings from the cost analysis showed that new, high performance windows are by far the most expensive measure, costing at least double that of common retrofit options when considering materials, installation and general construction commonly required for an existing home. In all climate zones analyzed, cellular shades, interior storm panels and various exterior storm window configurations offer a higher average return on investment compared to new, efficient replacement windows.

The Bottom Line. Retrofitting windows with high performance enhancements can result in substantial energy savings across a variety of climate zones. Selecting options that retain and retrofit existing windows are the most cost effective way to achieve these energy savings and to lower a homes carbon footprint. Retrofits extend the life of existing windows, avoid production of new materials, reduce waste and preserve a homes character.

WINDOW PRESERVATION STANDARDS COLLABORATIVE

In the Fall of 2010, the top preservation trades people in North America and Europe met for the International Preservation Trades Workshop in Frankfort, Kentucky. Among the gathered were some of the top window restoration experts in the country. Five of these window experts, Duffy Hoffman, John Leeke, Jim Turner, David Gibney and Bob Yapp met and decided it was time to create national standards for the repair and weatherization of old and historic windows.

Using cutting-edge window testing technology, theCollaborative's testsare verifying "what most people in historic preservation have known for years, old and historic windows can cost effectively be made as or more energy efficient than new, disposable replacement windows."

The National Trust for Historic Preservation's Weatherization Guide for Older and Historic Buildings includes guidance on why and how to care for older and historic windows:

"Window Repair, Rehabilitation and Replacement" , Peter Baker, P.E.

This report was prepared for Building America, Building Technologies Program, Office of Energy Efficiency and Renewable Energy, U.S. Department of Energy to evaluate advanced retrofit measures. A balanced approach is presented to guide contractors and homeowners to decide whether to repair or replace considering many factors, one of which is historic preservation. November 2011

"A Comparative Study of the Cumulative Energy Use of Historical Versus Contemporary Windows" By Frank Shirley, AIA, Fred Gamble, PhD, Jarod Galvin, RA, LEED AP

This study compares the life-cycle costs of two residential window systems in a pre-1940 house in Boston, Massachusetts. One is an original double-hung window with a new triple-track storm unit. The other is a new, vinyl, double-hung replacement window. Results are obtained from an algorithm that yields the total present value of all costs associated with a window system over its entire life, including acquisition, installation, maintenance, and energy. December 2010

"Field Evaluation of Low-E Storm Windows" By S. Craig Drumheller- NAHB Research Center, Christian Kohler- Lawrence Berkeley National Laboratory, Stefanie Minen-Utilivate Technologies

A field evaluation comparing the performance of low emittance (low-e) storm windows with both standard clear storm windows and no storm windows was performed in a cold climate. Six homes with single pane windows were monitored over the period of one heating season. The homes were monitored with no storm windows and with new storm windows. Simple paybacks for the addition of the storm windows were 10 years for the clear glass and 4.5 years for the low-e storm windows. December 2007

"The Effects of Energy Efficiency Treatments on Historic Windows" by Larry Kinney and Amy Ellsworth January 2011

This study focused on empirical testing of the energy efficiency and economy of a range of options for upgrading the energy performance of historic windows. The study involved retrofitting windows in a test home in a historic district in Boulder, Colorado. It included testing in a window laboratory facility developed for the study.

"Thermal Performance of Traditional Windows" by Dr. Paul Baker for Historic Scotland Revised September 2010

Technical Paper 1 tested the use of curtains, shutters, blinds, and secondary glazing. All were shown to reduce the heat loss through the glazing to varying degrees. Secondary glazing was found to be the most effective overall option, as it reduced heat loss through the window by 63%. Timber shutters are the most effective option of the traditional methods, reducing heat loss by 51%; curtains reduced heat loss by 14%; a Victorian roller blind reduced heat loss by 28%; a modern roller blind reduced heat loss by 22%. The greatest reductions in heat loss came from combining these measures (i.e. blinds, shutters and curtains all closed) and by adding extra insulation to these options.

"Slim-profile double-glazing in listed buildings: Re-measuring the thermal performance" by Nicholas Heath & Paul Baker, Historic Scotland 2013

Technical Paper 20 remeasures the efficiency of previously installed slim-profile double glazing in existing historic windows.

"Thermal Assessment of internal Shutters and Window Film Applied to Traditional Single Glazed Sash and Case Windows" by John Currie, Julio Bros Williamson, Jon Stinson & Marie Jonnard, Historic Scotland

Technical Report 23 assesses the effectiveness of two inexpensive and minimally invasive methods for improving the thermal performance of single glazed windows. This technical paper demonstrates that a range of options, including minimally invasive and inexpensive methods, can play a worthwhile role in the overall thermal improvement of buildings.

"Thermal Performance of Historic Windows" by Chris Wood, http://www.buildingconservation.com (England)

"An Analysis of the Thermal Performance of Repaired and Replacement Windows", PDF, Robert Score and Bradford Carpenter, APT Bulletin 40:2, 2009

Window Energy Analysis, Keith Haberern, P.E.

Replacement Windows and Furnaces in the Heartland: Indianas Energy Conservation Financial Assistance Program by William H. Hill. This is the 1990 study that demonstrates a four hundred year payback using replacement windows.

Measured Winter Performance of Storm Windows by J. H. Klems. This Berkeley storm window research focuses on north-facing storm windows using low e glazing. It uses rigorous scientific analysis to conclude that no difference is found in performance between the low-e storm with an original window and a low-e replacement window.

Building Regulations and Historic Buildings: balancing the needs for energy conservation with those of building conservation The English Heritage Interim Guidance article touches on all parts of preservation and conservation of power and fuel, and the chapter on windows is very relevant.

Repair or Replace Windows in Historic Buildings: Arriving at a Sustainable Solution The Heritage Canada file contains two articles, one from Andrew Powter and Craig Sims discussing how to arrive at a decision to replace or repair original windows, and Susan Turner explains the sustainable nature of window repair rather than replacement.

Life Cycle Of Window Materials - A Comparative Assessment by Asif, Davidson and Muneer. A comparative life cycle assessment of the environmental impact of different window materials is included for its interesting materials energy cost analysis.

What Replacement Windows Cant Replace: The Real Cost of Replacing Historic Windows Walter Sedovic and Jill Gotthelf provide an excellent discussion of the comparative value of window replacement versus repair. Many aspects of sustainability are considered.

Testing the energy performance of wood windows in Cold Climates by Brad James, Andrew Shapiro, Steve Flanders and Dr. David Hemenway is a thoroughly researched paper that concludes that historic windows should not be replaced for energy considerations alone, as retrofitted and replacement windows perform similarly.

Lincoln Hall Windows Research Report: A Case Study of Options for Treatment for Windows at Lincoln Hall, University Of Illinois, Urbana Champaign This report provides empirical data to assess window repair or replacement options for a proposed LEED Gold project, addressing the existing windows in terms of energy consumption.

"What Shall We Do With Our Windows?" by Gordon Bock, Traditional Building Magazine, October 2014

"Storm Windows Save Energy" Home Energy Magazine, 1/28/14 "Old Windows Find a Following" by Katie Zezima. New York Times 7/27/2011.

Windows Aren't Always A Clear Path for Savings: In Quest to Boost Energy-Efficiency, Small Changes Might Have Bigger Payoff by Terri Rupar.Washington Post5/16/2009.

Thinking Of New Windows? Save Your EnergyNational Public Radio (NPR) 10/11/2009.

"What Should I Do About My Windows?" by Bill Mattinson, Ross DePaola, and Dariush Arasteh for Home Energy Magazine. August 2002

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WINDOW REPAIR & RETROFIT: STUDIES & RESEARCH

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Welcome to Window Works of Chattanooga. We are here to provide your home with the best custom made windows on the market made by Alside.Alside sets the standard by which other replacement windows are measured. Over fifty years of innovation has resulted in a collection of windows that are designed and engineered to provide beauty, performance, ease of operation, virtually no maintenance, and increased energy-efficiency.

You will find our replacement windows to be the most affortable in the Chattanooga area while providing the higest of quality. Please browse our website to familarize yourself with our company.

Window Works of Chattanooga is a local family owned and operated business being able to relate closely with our customer the homeowner. We are focused on providing high-quality service and customer satisfaction - we will do everything we can to meet and exceed your expectations.

With a variety of custom windows to choose from, we're sure you'll be happy working with us. Look around our website and if you have any comments or questions, please feel free to contact us.

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Window Works Of Chattanooga - Welcome - Chattanooga, TN

While window contributes to heat loss in most of the homes, it also supports glass panes to protect home from water, dust and other detrimental elements. There are times when the window gets stuck especially when they are painted, venetian blinds do not work right, screens get ragged and glass gets broken. But, not many people know how to keep their windows working properly. This is when they need window repair services in the vicinity.

Window repair and installation services from Window Repair NYC address frame repair problems for many types of windows that include Double Hung Window, Picture Window, Bay Windows, Casement Window, Bow Windows and Basement Window. If you are fed up of the noise and the dirt of the city that makes way into your clean home, then we can proffer you a simple, sensible and affordable solution to get rid of the noise. For old home, repairs are made to the window made of wood, where every single occurrence of splintered wood is repaired. Our window fix and repair services extend the tenure of wood windows, which are certainly the accent of architectural style in your home.

Window Repair NYC specializes in assisting homeowners to get the most from skilled and veteran professionals in the locality. The company is fully licensed and insured to bring you the assurance that you may expect your service provider to have. For homeowners facing some problems with windows and doors at home, we offer a cost-free and no obligation quote. Besides, we even visit your home to look into the matter before repairing windows. Our professionals offer you the sincere advice as to whether the time has come to go for window repair and installation services or not. All you are required to do is just give us a call as and when you stumble upon the problem. Our representative immediately rushes to your home after getting the call and explains you the entire process.

By choosing our company for window repair and replacement, you can grab the rare opportunity to trim down your overall costs, incurred otherwise from window installation and window repair. Be it a metro area or a suburban area, we are always ready to visit your home with all the equipments required for repairing and fixing windows. In addition, our experts offer you honest advice on what will be the best solution for you after analyzing the situation properly. Window Repair NYC guarantees extensive knowledge, expert professionals and durable results. With a perfect combination of professionalism and quality repair services, you can save both your time and money.

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Window Repair NYC: Best Window Repair & Installation Experts

Looking for information on home window types, let us help you with our guide to home window types. We'll describe for you the different window types for your home to aide you in that final decision of what type is right for you.

Casement windows are swinging, crank windows. They swing from the side and typically in an outward fashion, however, they can be designed to swing inward. They are operated with a crank mechanism rather than a push open or pull open method like most other windows.

Double hung windows are the most commonly used type of windows. They open either by pushing the bottom sash up or pushing the top sash down and when partially opened will stay in place. With double hung windows the sashes of the window not only slide down or up but also opens inward and outward allowing for easy and convenient cleaning especially on upper floors of the house.

Sliding windows are exactly what their name implies. They slide open similar to how a patio door slides open, however, unlike a patio door that opens from both sides a sliding window has one fixed side and one sliding side.

Hopper windows are more commonly used in basements. They are similar to a casement window in that they are hinged but instead of hinges on the side and opening out they are hinged on the bottom and open inward from the top.

Awning windows are similar to hopper windows with the exception that they are hinged on the top instead of the bottom and swing open from the bottom outward instead of from the top inward. Awning windows typically have a crank or some other similar mechanism that is important in keeping the window open in the event of high wind where without the crank they would slam shut.

Fixed windows are exactly that, fixed. They are not hinged, they do not open in any way so they do not offer any kind of ventilation whatsoever. Fixed windows are by far the least expensive of all windows because they do not require any hardware. They also offer the best seal and therefore are the most energy efficient of windows.

Bay windows have multiple panels that extend beyond the wall of your home. They are great for creating the illusion of a larger area in a small space. Commonly bay windows have a fixed center window and casement windows on the sides so you have the choice of having a bay window that can be opened for air and ventilation.

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Window Replacement - Windooows.com

Replacement windows are one of the best investments you can make in your home. By replacing your home windows you can save monthly on your heating and cooling costs, and add curb appeal with an improved visual appearance. When it comes to replacement windows, you have a big task ahead of you. We have constructed our library to be used as a resource for homeowners with home replacement windows projects. Some of what you will find in our library are:

Replacement windows have evolved greatly over the years. Wood is still the standard, but vinyl replacement windows and fiberglass are becoming more common. We've listed some of the most popular materials for replacement windows:

Replacement windows made by companies such as Andersen Windows, Jeld-Wen (Jen-Weld) Windows, Pella Windows, and Milgard Windows are very similar. We have constructed a list of the most popular styles of replacement windows and their descriptions. Here are the most common styles of replacement windows:

Replacement windows are a great investment. You'll want to make sure you are choosing the right replacement windows for your home and your budget. We offer Free Replacement Window Quotes from local contractors.

Replacement Window Materials Aluminum Windows Fiberglass Windows Steel Windows Vinyl Windows Wood Windows Replacement Window Manufacturers Andersen Windows Certainteed Windows Gerkin Windows Hurd Windows Jeld-Wen Windows Loewen Windows Marvin Windows Milgard Windows Napco Windows Pella Windows Silver Line Windows Simonton Windows Thermal Industries Windows Weather Shield Windows Replacement Window Styles Awning Windows Bay Windows Bow Windows Casement Windows Double Hung Windows Fixed Frame Windows Garden Windows Single Hung Windows Skylight Windows Sliding Windows

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Replacement Windows - Installation for Vinyl, Wood ...

Tweaking.com - Windows Repair is a tool designed help fix a large majority of known Windows problems including; registry errors, file permissions, issues with Internet Explorer, Windows Updates, Windows Firewall and more. Malware and poorly installed programs can modify your default settings resulting in your machine working badly - or worse. With Tweaking.com Windows Repair you can restore Windows original settings fixing many of these problems outright.

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Tweaking.com - Windows Repair

Award of Excellence 2006 - 2015

Gulf Coast Windows has been an established business in the greater Houston area for over 35 years. While we are best known for our services of installing and replacing windows, we also install and replace composite fiberglass entry doors. Our company prides itself in offering trustworthy and reliable service to the great city of Houston and its surrounding areas. We've been the recpient of the prestigious Pinnacle Award from the Better Business Bureau (BBB); the Pinnacle Award is the highest award presented by the BBB within their business category. In addition, the BBB has also given us the Award for Excellence from 2006 through 2015. At Gulf Coast Windows, when it comes to be the meeting all of your window and glass door replacement needs, we guarantee the best service in Houston.

More than Just a Window

Gulf Coast Windows offers a variety of solutions for new or replacement windows. Our composite windows, one of our most energy efficient and technologically advanced products, are designed to meet the specific solar and energy needs of Houston area residents, and can be completely customized to improve performance based on a number of different factors, including the design of your home and your personal preferences!

The secret behind the windows performance is its exceptionally low air infiltration ratings, lowframe conduction and our exclusive Heat Reflectorcoatings with Argon Gas. These unique benefitscan lower the energy consumption of a typical home by as much as 40%.

Our composite windows are easy to install and easy to clean, which makes them very popular. They can be customized to fit any size opening, and they provide a powerful seal in order to reduce the risk of air leaks. These windows can tilt or rotate to simplify and speed up cleaning. Our in-house experts are always ready to demonstrate our composite windows and discuss your windows options.

If you're not sure what type of doors or windows you need, our friendly and professionally trained staff will assist you in selecting the right products for you, whether it be composite vinyl, aluminum, wood clad, hurricane, or storm windows and doors. Please call us or complete our quote form to discuss your needs. We offer free in-house consultations.

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Gulf Coast Windows - Window replacement company, Houston

Windows provide our homes with light, warmth, and ventilation, but they can also negatively impact a home's energy efficiency. You can reduce energy costs by installing energy-efficient windows in your home. If your budget is tight, energy efficiency improvements to existing windows can also help.

You can improve the energy efficiency of existing windows by adding storm windows, caulking and weatherstripping, and using window treatments or coverings.

Adding storm windows can reduce air leakage and improve comfort. Caulking and weatherstripping can reduce air leakage around windows. Use caulk for stationary cracks, gaps, or joints less than one-quarter-inch wide, and weatherstripping for building components that move, such as doors and operable windows. Window treatments or coverings can reduce heat loss in the winter and heat gain in the summer. Most window treatments, however, aren't effective at reducing air leakage or infiltration.

If your home has very old and/or inefficient windows, it might be more cost-effective to replace them than to try to improve their energy efficiency. New, energy-efficient windows eventually pay for themselves through lower heating and cooling costs, and sometimes even lighting costs.

When properly selected and installed, energy-efficient windows can help minimize your heating, cooling, and lighting costs. Improving window performance in your home involves design, selection, and installation.

Before selecting new windows for your home, determine what types of windows will work best and where to improve your home's energy efficiency. It's a good idea to understand the energy performance ratings of windows so youll know what energy performance ratings you need for your windows based on your climate and the home's design.

For labeling energy-efficient windows, ENERGY STAR has established minimum energy performance rating criteria by climate. However, these criteria don't account for a home's design, such as window orientation.

Windows are an important element in passive solar home design, which uses solar energy at the site to provide heating, cooling, and lighting for a house. Passive solar design strategies vary by building location and regional climate, but the basic window guidelines remain the sameselect, orient, and size glass to maximize solar heat gain in winter and minimize it in summer.

In heating-dominated climates, major glazing areas should generally face south to collect solar heat during the winter when the sun is low in the sky. In the summer, when the sun is high overhead, overhangs or other shading devices prevent excessive heat gain.

To be effective, south-facing windows should have a solar heat gain coefficient (SHGC) of greater than 0.6 to maximize solar heat gain during the winter, a U-factor of 0.35 or less to reduce conductive heat transfer, and a high visible transmittance (VT) for good visible light transfer. See Energy Performance Ratings to learn more about these ratings.

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Energy-Efficient Windows | Department of Energy

Glass is an amorphous (non-crystalline) solid which is often transparent and has widespread practical, technological, and decorative usage in things like window panes, tableware, and optoelectronics. The most familiar, and historically the oldest, types of glass are based on the chemical compound silica (silicon dioxide), the primary constituent of sand. The term glass, in popular usage, is often used to refer only to this type of material, which is familiar from use as window glass and in glass bottles. Of the many silica-based glasses that exist, ordinary glazing and container glass is formed from a specific type called soda-lime glass, composed of approximately 75% silicon dioxide (SiO2), sodium oxide (Na2O) from sodium carbonate (Na2CO3), calcium oxide, also called lime (CaO), and several minor additives. A very clear and durable quartz glass can be made from pure silica; the other compounds above are used to improve the temperature workability[clarification needed] of the product.

Many applications of silicate glasses derive from their optical transparency, which gives rise to one of silicate glasses' primary uses as window panes. Glass will transmit, reflect and refract light; these qualities can be enhanced by cutting and polishing to make optical lenses, prisms, fine glassware, and optical fibers for high speed data transmission by light. Glass can be colored by adding metallic salts, and can also be painted. These qualities have led to the extensive use of glass in the manufacture of art objects and in particular, stained glass windows. Although brittle, silicate glass is extremely durable, and many examples of glass fragments exist from early glass-making cultures. Because glass can be formed or molded into any shape, and also because it is a sterile product, it has been traditionally used for vessels: bowls, vases, bottles, jars and drinking glasses. In its most solid forms it has also been used for paperweights, marbles, and beads. When extruded as glass fiber and matted as glass wool in a way to trap air, it becomes a thermal insulating material, and when these glass fibers are embedded into an organic polymer plastic, they are a key structural reinforcement part of the composite material fiberglass.

In science, the term glass is often defined in a broader sense, encompassing every solid that possesses a non-crystalline (i.e. amorphous) atomic-scale structure and that exhibits a glass transition when heated towards the liquid state. Thus, porcelains and many polymer thermoplastics familiar from everyday use are physically glasses also. These sorts of glasses can be made of quite different kinds of materials: metallic alloys, ionic melts, aqueous solutions, molecular liquids, and polymers. For many applications (bottles, eyewear) polymer glasses (acrylic glass, polycarbonate, polyethylene terephthalate) are a lighter alternative to traditional silica glasses.

Silica (the chemical compound SiO2) is a common fundamental constituent of glass. In nature, vitrification of quartz occurs when lightning strikes sand, forming hollow, branching rootlike structures called fulgurite.

Fused quartz is a glass made from chemically-pure silica. However, its high melting-temperature (1723C) and viscosity make it difficult to work with.[1] Normally, other substances are added to simplify processing. One is sodium carbonate (Na2CO3, "soda"), which lowers the glass transition temperature. The soda makes the glass water soluble, which is usually undesirable, so lime (calcium oxide [CaO], generally obtained from limestone), some magnesium oxide (MgO) and aluminium oxide (Al2O3) are added to provide for a better chemical durability. The resulting glass contains about 70 to 74% silica by weight and is called a soda-lime glass.[2] Soda-lime glasses account for about 90% of manufactured glass.

Most common glass contains other ingredients to change its properties. Lead glass or flint glass is more 'brilliant' because the increased refractive index causes noticeably more specular reflection and increased optical dispersion. Adding barium also increases the refractive index. Thorium oxide gives glass a high refractive index and low dispersion and was formerly used in producing high-quality lenses, but due to its radioactivity has been replaced by lanthanum oxide in modern eyeglasses.[citation needed] Iron can be incorporated into glass to absorb infrared energy, for example in heat absorbing filters for movie projectors, while cerium(IV) oxide can be used for glass that absorbs UV wavelengths.[3]

The following is a list of the more common types of silicate glasses, and their ingredients, properties, and applications:

Another common glass ingredient is crushed alkali glass or "cullet" ready for recycled glass. The recycled glass saves on raw materials and energy. Impurities in the cullet can lead to product and equipment failure. Fining agents such as sodium sulfate, sodium chloride, or antimony oxide may be added to reduce the number of air bubbles in the glass mixture.[2]Glass batch calculation is the method by which the correct raw material mixture is determined to achieve the desired glass composition.

Glass is in widespread use largely due to the production of glass compositions that are transparent to visible light. In contrast, polycrystalline materials do not generally transmit visible light.[7] The individual crystallites may be transparent, but their facets (grain boundaries) reflect or scatter light resulting in diffuse reflection. Glass does not contain the internal subdivisions associated with grain boundaries in polycrystals and hence does not scatter light in the same manner as a polycrystalline material. The surface of a glass is often smooth since during glass formation the molecules of the supercooled liquid are not forced to dispose in rigid crystal geometries and can follow surface tension, which imposes a microscopically smooth surface. These properties, which give glass its clearness, can be retained even if glass is partially light-absorbingi.e., colored.[8]

Glass has the ability to refract, reflect, and transmit light following geometrical optics, without scattering it. It is used in the manufacture of lenses and windows. Common glass has a refraction index around 1.5. This may be modified by adding low-density materials such as boron, which lowers the index of refraction (see crown glass), or increased (to as much as 1.8) with high-density materials such as (classically) lead oxide (see flint glass and lead glass), or in modern uses, less toxic oxides of zirconium, titanium, or barium. These high-index glasses (inaccurately known as "crystal" when used in glass vessels) causes more chromatic dispersion of light, and are prized for their diamond-like optical properties.

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Glass - Wikipedia, the free encyclopedia

Home > Uncategorized > Solved: Missing Base Filtering Engine in Windows 7 December 12th, 2011 admin

UPDATE 21 Jan 2012: If you are missing just BFE, the information below should be helpful. However, if you are missing BFE, Windows Firewall, Security Center and a couple of other services after a virus infection, you are going to need a more comprehensive security services fix. The second post by Farstrider (that starts you can also try this:) works great. After getting the Norton 5013,3 error on yet another customer computer, I found this solution fixed the Norton problem without requiring me to reinstall the OS. HOWEVER, even still the Security Center service was still not starting, fixing that required me to download and run the Security Center registry entry from here (reboot afterward). Good Luck.

It looks like there is a virus now that can take out the Base Filtering Engine Service in Windows 7, and I suppose then in Vista and XP as well. I noticed this problem on a computer that I removed a virus from. Everything looked fine until I went to install Norton Antivirus and it barfed with an error message about Error 5013,3. The instructions to fix the problem included restarting the Base Filtering Engine Service but oops, it wasnt even there. As it turns out, the fix for this is easier than you might think.

The fix I used was to recreate the BFE service entry in the registry, which had been deleted. The registry entry that needs to be recreated is:

HKEY_LOCAL_MACHINESYSTEMCurrentControlSetservicesBFE

According to this Microsoft Technet article, you can just export the key from a working machine of the same OS and import it (just double click on the exported and moved .reg file) into the problem machine. I can tell you this absolutely worked like a charm for me.

WordPress wont let me attach a copy of my Windows 7 x64 BFE entry, but if you need one, this link should work, otherwise leave a comment and Ill try and mail it to you..

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Lexington Computer Repair BlogSolved: Missing Base ...