Windows and Window Film
- Knowledge of windows and glass enhances your ability to be successful in the window film industry. Because we are a retrofit business, we have to deal with the many types of existing windows in homes and commercial buildings.
- A glazing system is made up of glass, framing systems, and glazing materials. Once added, window film also becomes part of the glazing system.
- The type of glazing system determines how we measure the windows, install the product and can affect the price of the job.
- Annealed glass, also known as float, plate or sheet glass, is the most common glass in windows today. It is manufactured by pouring molten glass on molten tin. As it cools, the glass floats on the surface to form a large sheet. Although it is the least costly way to make glass and it can be cut to size and shape, this glass is not very strong. Annealed glass does not meet minimal standards for safety (ANSI Z97.1), and it breaks in shards which can become lethal when air-borne.
- Heat treated glass takes longer to make than float glass because it cools more slowly. The result is a glass that is twice as strong as annealed glass. But this glass still does not pass ANSI Z 97.1 and it also breaks in dangerous shards.
- Tempered glass is manufactured by heating and then rapid cooling to increase the strength of the glass. This glass is four times stronger than annealed glass and is resistant to temperature changes. Tempered glass meets the ANSI Z 97.1 code and breaks in people friendly pieces, referred to as dice. However tempered glass is not a security product. Even though it takes more impact than other types of glass it breaks in very small pieces to make entry into the space easy. Seven or 8- mil safety film added to tempered glass makes entry after breakage more difficult. The down side is this glass cannot be cut to size.
Pattern of Breakage
- Tempered after Breakage
- Annealed glass breaks in large, dangerous shards.
- Tempered glass breaks tn small, safer pieces called dice.
- Though single glazing (a single sheet of glass) was once the standard, dual pane glazing, also known as insulating glass units (IG Units) has become the standard in most of the country. Insulated glass actually has nothing to do with the glass, but everything to do with the way the glass is put into the glazing system.
- IG units consist of two or more panes of glass separated by a thin air space. The air space decreases the conduction of heat through the glass. Though a single-glazed window offers an insulating value of about R-1, a dual- glazed model provides twice the value at R-2. For very severe climates, 3 or 4 panes of glass may be used. It is the air space created by the integrated seal that provides the insulating value in an IG unit.
- The integrity of the seal is critical to the life of these windows. If the seal is damaged water vapor gets between the two panes of glass and makes these windows appear cloudy. Two further improve the energy performance of these windows, an inert gas, such as argon, may be used in the air space to slow the transfer of heat through the space. Some gases slow heat transfer more than others.
TYPICAL IG UNIT
- Air Space
- Desiccant Fill
- Metal Spacer
- Secondary Seal
- Primary Seal
- The air space in an IG unit decreases the conduction of heat through a window. Conduction is reduced further with the addition of a gas.
- ANSI Z 97.1 is a test method developed to insure the break-safe characteristics of glass. This need developed with the introduction of sliding glass doors. By the late 60’s and early 70’s the number of lethal injuries involving these doors was at a peak. ANSI Z 97.1 was developed to assure glass would not be lethal if a child ran into a sliding glass door. Today, local and state building codes require that sliding glass doors and other windows near the floor meet this standard.
- CPSC, CRF 1201 is a similar test standard that measures the ability of glass to be safe at a greater impact force. Safety film 4-mil and thicker safety and security window film added to annealed or heat treated glass meets the requirements ANSI Z97.1. Safety film 7-mil and thicker meets requirements for passage of CPSC, CFR 1201.
- Many different types of treatments may be done in the manufacturing process to enhance the energy performance properties of annealed, heat-treated or tempered glass. IG units may have one or more of these types of glass treatments incorporated into the framing system.
- Standard window glass allows the sun’s energy to I pass through it. However, at night, it is equally effective at emitting infrared heat
- Impact-resistant glass is not coated or colored but is related to the construction of the sheets of glass that are put into the framing system. This is the dominant glass in new construction in areas which have adopted wind-loads into building codes.
- Laminated glass is made by bonding a tough layer of polyvinylbutyral (PVB) between two panes of glass under heat and pressure. The result is a laminated glass, similar to that found in automobile windshields.
- When struck with flying debris, laminated glass cracks or shatters, but the PBV layer holds the window pane together, and glass fragments tend to adhere to the plastic interlayer. This prevents penetration at the window and the consequential structural and water damage or loss due to burglary.
- Laminated glass varies in strength based on the thickness of the PVB layer, as well as the type of glass used on each side of that layer. The glass may be tempered on both sides, tempered on one side with annealed on one side or annealed on both sides. Because tempered glass is stronger, using it means stronger laminated glass.
Window Film And Specialty Glass Treatments and Glazing Systems
- Many low-e coatings are not friendly to window film. Where a low-e coating is located determines how appropriate a particular window film application may be. A low-e coating on surface 2 tends to be film friendly. However, Tint Depot has prepared a “Film-to-Glass Application Chart” (Catalog # 0234) to clarify which film are appropriate when the low-e coating is on surface 3.
- Impact resistant glass is made up of different materials that expand and contract at different rates when heated by the sun. Window films with low solar energy absorption should be used. Low solar energy absorption films are rated as #1 on the “Film to- Glass Application Chart”.
- Some caution needs to be used with the IG units and window film. If the pane of glass with film absorbs more heat and expands more than the pane without film, the seal may be compromised. To prevent this, again we consult the “Film-to-Glass Application
TYPICAL IG UNIT
- Air Space
Window film is applied to surface ; number 4 of an IG unit
- The frame of the glazing unit supports the glass, minimizes glass edge movement, keeps water and air from the building, and provides cushioning and thermal isolation for the glass. The material of the framing system affects the energy performance of the frame and can affect the ease with which film is installed. Three major types of windows frame materials are:
- Wood Frames are found mostly in older buildings or homes. Wooden frames utilize a chalky glazing compound to hold the glass in the frame. The older the frame, the more fine powdery chalk dust settles on the frames and glass. Today, wooden frames are found in expensive window units in upscale homes. The new wooden frames have gaskets or sealants making window film installation much easier than the older windows with glazing compounds.
- When installing film on windows with older wooden frames both the chalky glazing compound as well as the flaking paint can make them hard to clean. The glazing compound is often uneven, making it difficult to cut a straight line at the edge of the film.
- Steel Frames are generally found in older types of buildings and homes. Steel frames usually use the same type of a chalky glazing compound as seen in older wooden windows. When installing film on steel windows, the frame and the glazing compound may be in some state of deterioration. The glazing compound is generally dried out and the frame may be flaking paint or even rust, making cleaning and cutting edges difficult.
- Aluminum Frames are the primary glass structural support used for glazing units today. The vast majority of residential as well as large display windows are in aluminum frames.
- Glass installed in aluminum windows may be secured with caulk, gaskets or a sealant. Check the gaskets or sealants carefully to be certain the window is stable and the gaskets are resilient before installing film.
- Newer framing materials in the market include:
1. Vinyl frames
2. Vinyl clad
- Vinyl Frames are made primarily from polyrvinyl chloride (PVC). Some manufacturers fill the hollow parts of the frame with foam or fiberglass insulation. Vinyl frames are available in many styles and are generally considered low maintenance since they never need painting. However, ultraviolet (UV) light can fade colors and cause yellowing and “crazing” of the vinyl’s surface.
- Vinyl frames are also not very rigid, requiring large openings to have an internal metal extrusion to support the frame. Vinyl window frames can also soften, warp, and twist if heat builds up within the frame. In very hot, sunny climates, direct exposure to sunlight is not recommended
- Vinyl Clad frames are made by coating or using extruded vinyl over an aluminum or wooden frame. This reduces the need to paint the window frame. Window film installers should take care during installation as it is possible to cut through this material with the knife used in film installation.
- Fiberglass Frames are made of a fiberglass and resin composite. Some frames are hollow; others are filled with fiberglass insulation. Most are pre-finished with a polyurethane coating. They are resistant to warping, shrinking, and rotting and are relatively strong and durable. These window frames are a new development and are not widely available yet.
- Pane or Lite
The frame surrounds a window and a sash surrounds the glass pane (also known as a lite).
Gaskets, Sealants and Tapes
- Gaskets, sealants and tapes are used in a window frame to provide an effective seal, cushion the glass and provide thermal insulation for the glass. As these materials age, they can become brittle and lose their ability to function. Older materials often flake and can make cleaning windows more difficult.
- Gaskets are solid vinyl sections that go between the glass and the frame. To seal out the elements. They should remain elastic over the life of the window. These will be found in most commercial aluminum window frames and some residential sliding glass doors.
- Sealants are used alone or with gaskets and tapes. Sealants are often referred to as caulk but they are very different materials. Modern sealants are resilient and long lasting, made of silicone, polysulfides, polyurethane or acrylics. Caulks do not use the long lasting higher quality materials as used in sealants. Sealants are climate specific so what is applicable in northern climates is not necessarily the right choice for southern climates. Many low-end residential windows use sealants to hold glass in place. These materials are applied with a sealant gun.
- Tapes are often used in combination with gaskets or sealants to hold a window temporarily while place vinyl gaskets or while sealants cure.
- Of the many window styles found in buildings, some window styles are easier to install window film on than others. Some window types are:
- A casement window is hinged on one side and swings out when you turn a crank (some are inward-swinging). Because it opens fully, it affords good ventilation and is easy to clean.
- A double-hung window allows you to raise the bottom or lower the top for excellent ventilation control. Single-hung windows look similar, but only the lower sash opens.
- A slider window is made from two separate sashes fit into tracks. One sash may be stationary. A slider is easy to operate and most types are particularly weather-tight.
- An awning window hinges at the top and tilts out at the bottom, providing partial ventilation. These are often used above doors or other windows or may be grouped in sets.
- A Jalousie or “louvered” window is excellent for ventilation but a poor insulator-they leak a great deal of air. These often have a textured glass that is not appropriate for window film.
- A hopper window hinges at the bottom. A hopper is normally used for ventilation above a door or window, where protected by building overhangs.
- A round-top and other geometrically-shaped windows are used as architectural • accents. These generally use annealed glass and are cut to shape, making glass breakage because of imperfect edges a problem.
- A bow window is made from several windows positioned side-by-side to create an arcing form. They are similar to bay windows.
- A tilt-tum window is generally found in new houses or in replacement windows. It tilts out for ventilation but also can be opened fully for cleaning or as an emergency escape. The tilt may be from a vertical or a horizontal side.
- The bay window is made from a central sash and two angled side sashes. It is used to expand the glass area in a room for drama, light or views. The angled side windows are often operable casements or double-hung windows.
- A seamless bent-glass comer window is a fairly new product that offers unobstructed views at the corner of a house. This window has two pieces of glass butted to form a corner and secured with a clear sealant. Film may be used on these windows but it must be trimmed next to the sealant. It cannot bridge the sealant.
- Colonial or French Panes may be found in double hung, casements, sliders, bay, bow, tilt windows as well as sliding glass doors and patio doors. Colonial panes divide a window into small squares or rectangles. The dividers, called mullions, may be permanent or removable. If they are removable, remove before applying window film, but not when doing a Solar Graphic. If they are permanent, pre-cutting the film to the exact size will make adding window film easier. Because applying window film on these takes longer, you may
- Glass block is a light-allowing alternative to conventional windows, used both in exterior and interior walls. Various patterns allow varying degrees of view or privacy. When these are exposed to sun they can admit a lot of heat. Glass blocks are not smooth so window film cannot be applied to solve heat gain problems.
- A terrace or patio door is hinged and has glass lites. Hinged glass-lite doors mounted in pairs that swing independently are called French doors. The small panes in these windows are very similar to colonial panes.
- An exterior sliding door has one fixed panel and one panel that glides along top and bottom tracks or two panels that move. Three or more panels may operate to create a whole wall of glass that opens. These doors operate easily, seal out the weather while admitting plenty of light.
Glass and Glazing
Knowledge of windows only enhances your knowledge of film,,.
- To understand the glass and framing systems used in residential and commercial windows.
What we will cover:
- Framing systems
- Glazing materials
- Glass types
- IG Units
Knowledge of Windows and Glass
- Critical for selecting optimum film for optimum performance
- Film choice must be compatible with glass and window construction
- The type of glass and glazing system that film is applied to is critical to the performance of film.
- Choosing film involves matching the glass and window type with a film that performs well on that glazing system.
- Your customers satisfaction with window film not only depends on the quality of film supplied by Tint Depot. Films but also on the glazing system that it becomes part of.
- Understanding and being able to identify both glass and framing system allows you to become an expert on what film is appropriate with which glazing system and why.
- The glazing system Is made up of:
- The framing system
- The glazing materials
- The glass
- Film, if added
- A glazing system is comprised of:
- glass or glass with film
- framing system
- glazing materials (gaskets, seals and materials) used to stabilize the glass in the frame.
Types of Glass
- Chemically strengthened (Seldom seen in the film business)
- Glass is one of the oldest man-made materials. The basic materials has remained unchanged over centuries.
- Types of glass are categorized by the amount of heat used in the manufacturing process; hot, hotter and hottest.
- A the low end of the heat process scale is annealed glass, followed by heat-treated glass and then tempered glass.
Annealed Float Glass
- Most common window glass
- Molten glass poured on molten tin, glass floats on surface
- Less costly to make
- Can be cut to size or shape
- The most common window glass in annealed float glass, also known as annealed glass or float glass.
- This glass gets its name from the manufacturing process to make it. Molten glass is poured onto a bed on molten tin. The glass “floats” on the surface.
- The process used to make this glass is less costly than other methods. But the manufacturing methods leave it subject to easy breakage.
Annealed Float Glass…more
- Breaks in shards
- Listed tensile strength 5000 psi
- Does not meet ANSI Z97.1
- Annealed glass in the most fragile of all manufactured glass. It is subject to breakage from airborne debris, human impact, compression and thermal stress.
- When annealed glass breaks, it does so in many small and large sharp, irregular-shaped pieces (shards).
- Depending on why the glass broke, these jagged pieces of glass can be propelled at high speeds, capable of producing serious bodily injuries and even death (particularly in the cases of explosion, earthquakes, and serve wind storms).
- Tensile Strength is the load glass can take under a stretching type of lead before break (tear)
• When glass is vertical it loses 1/2 of its tensile strength
- NSI 297.1 is an impact test that is done with an impactor which swings into the glass.
- Instructor –
- Pass out test procedure.
- Slower to make because cools slowly
- Twice as strong as annealed glass
- Breaks in shards
- Listed tensile strength 10,000 psi
- Does not meet ANSI Z97.1
- The process used to make heat-treated glass is slower than making annealed glass.
- The process used is similar to tempered glass but the glass is not heated as hot and it is cooled more slowly.
- A piece of heat treated glass is about twice as strong as annealed glass. This type of glass has less bow and warp than tempered glass.
- Heat-treated glass is more resistant than annealed glass to:
- heat induced stress,
- wind-loads and
- impact of wind-borne debris and hail
- Heat treated glass is generally not accepted as a safety glazing product as it tends to break in the same jagged shards as annealed glass.
- Made with rapid heating and rapid cooling of edge, increasing edge strength.
- Four times stronger than annealed glass
- Listed tensile strength 20,000 psi
- Tempered glass is the result of both rapid heating and rapid cooling which changes the structure of the glass, an increase in strength.
- After a sheet of glass is heated to around 1200° F., the outer surfaces of the glass are rapidly cooled. This increases the strength at the edge of the glass.
- Tempered glass is about four times stronger than regular annealed glass. The change in the structure of the glass has two main benefits.
- glass is much stronger
- when broken, it goes into small fragments.
- The product’s main benefit is use in an area of high risk for accidental human impact.
- Sliding glass doors, shop front windows, and car windows are important applications for tempered glass.
More on Tempered Glass
- Resistant to temperature change.
- Cannot be cut.
- Breaks in people-friendly pieces.
- Not a security product.
- Meets ANSI Z97.1
- Tempered glass is very resistant to temperature change that can result in glass cracking. This is known as thermal stres fracture.
- Tempered glass is often used in coated or colored glass because these additions lead to an increase in solar heat absorption, which greatly stresses glass. Annealed glass would break easier under these conditions.
- Tempered glass has been available to the architectural market about 35 years.
- Tempered glass is not a security product.
- It is strong, it will break.
- Tempered glass will not protect merchandise in shop windows.
- It does not slow entry in smash and grab crimes. When in breaks, the pieces are more people friendly.
Pattern of Breakage
- Tempered after Breakage
- The breakage patterns of glass are important when window film is used to retain broken glass and when that film nust remain in the frame.
- Annealed, a large shard
- Tempered breakage in very small pieces. Safer to people but leaves very little In the frame.
- The more left in the frame the more there is for film to remain attached to after breakage.
Identifying Tempered Glass
– Has a corner etching, “bug”
– Sometimes the bug Is behind the frame
– All sliding glass doors must be tempered
- Most tempered glass is identified through a clearly visible corner etching stating that the glass complies with safety glazing standards. The presence of this marking is intended to assure that the glass is fully tempered.
- If there is no corner etching, the most direct way to tell the difference between annealed glass and heat strengthened glass in a window is by using two sheets of “polarized film”. One sheet should be positioned on each side of the glass pane and the character of the light that shines trough the glass is examined. Annealed glass will exhibit a neutral appearance, while heat-strengthened glass will appear mottled.
- Most glass in use around the world is annealed and sometimes heat-treated. This type of glass needs film to protect people from the sharp, jagged shards of broken glass. This means there is a tremendous market opportunity for window film in just the area of safety.
- Both heat treated and tempered glass are produced to a specified size and cannot be cut, edged or drilled once the glass has been heat treated.
The Role of Window Film
- Performs much like tinted or reflective glass
- More options available
- May be changed
- A retrofit product
- The window film business is based on the shortcomings of glass
- Film will address many of these shortcomings
- To understand glass is to realize where your opportunities are to make it better.
The Framing System
- Holds the glass
- Minimizes glass edge movement
- Keeps water and air out of the building
- Provides cushioning
- Provide thermal isolation for the glass
- The framing system of a window serves to:
- hold the glass
- minimize the edge movement of the glass
- keep water and air out of the building
- provide cushioning
- provide thermal isolation for the glass
- In residential applications, most frames are wood, vinyl, or aluminum. In most commercial buildings, aluminum and steel are most common.
- The framing system should provide support for the glass and is an integral part of the building structure.
Gaskets, Sealants, and Tapes
- Provide an effective seal
- Cushion the glass
- Provide a thermal insulation between glass and frame
- Glazing materials
- Gaskets, sealants, and tapes are used between the frame and glass to:
- provide an effective seal
- cushion the glass
- provide thermal insulation between the glass and the frame
- Solid or foam sections made of rubber.
- Must be resistant to the elements but must maintain elasticity over the life of the window.
- A gasket works by applying pressure on the edge of the glass to stabilize the glass
- Gaskets are solid or foam sections made of very elastic rubber type materials. These materials include neoprene, vinyl and silicone.
- Gasket materials must be resistant to the elements but must maintain elasticity and hardness over the life of the window.
- Used alone or with gaskets or tapes.
- Silicone, polysulfides, polyurethane, acrylics
- Some work in one climate, some in another.
- Applied soft with a sealant gun.
- Sealants may be used alone or may be combined with gaskets or tapes.
- Common sealants are silicons, polysulfides, polyurethane, butyl, acrylics and other materials that can be applied with a sealant gun, which used to be known as a caulking gun – say caulking and you will indicate you are old school. Sealant is the new word.
- This material is very soft when applied and may be shaped before it cures.
- Each of the types of sealant has varying levels of performance in different situations. The same sealant may not work equally well in both North Dakota and Arizona.
- Often used in combination.
- Can be used to hold window temporarily while sealants cure or placing a vinyl gasket.
- Tapes are used in the design of window systems and perform similarly to gaskets and tapes.
- Tapes normally have a rectangular cross section. Because the requirements of a framing system can be fairly demanding, in many cases, tape is used as a backup to a sealant application.
- The tape can provide a temporary cushioning effect while the sealant is curing or provide a holding method prior to the application of a vinyl gasket.
Various Framing Systems
- These gaskets can be installation challenges
- Structural Rubber Gasket
- Wood Sash
- Thin Tubular Aluminum Or Steel
- Thick Tubular Aluminum Or Steel
- Solid Aluminum Or Steel
- Some various cross sections of framing systems used in commercial buildings.
- Gaskets in these systems can provide challenges in film installation.
- Sometimes “uneven” gaskets are trimmed back to aide in film installation.
Insulated Glass Units
- Originally found only in colder climates.
- Consists of two or more sheets of glass fabricated into an IG Unit.
- Between the glass a clear airspace is filled with either air or an inert gas.
- An IG Unit consists of at least two sheets of glass that are separated by an airspace of constant thickness.
- Clear, annealed monolithic glass is most commonly used in these units.
- Other types of glass may be used to achieve certain performance characteristics.
Insulated Glass (IG) Unit
- Insulation comes from the air space.
- Breaks the conduction of heat from the room and the cold outside.
- The integrity of the seal is critical to the life of these units.
- Insulated glass has nothing to do with the insulating properties of the actual glass used in one of these units.
- The insulation properties of these windows come from the air space that is between two pieces of glass.
- Captured air in this airspace has a significant R-Value.
- (Review that R-value is the passage of heat through a material and is base on temperature difference.)
TYPICAL IG UNIT
- Desiccant Fill
- Metal Spacer
- Secondary Seal
- Primary Seal
- A spacer is used to create the airspace that is critical in these units.
- The seal between the glass sheets is designed to trap the
- The glazing materials serve to keep air, water and other items from entering the framing area that could cause deterioration of the unit.
- A desiccant may be incorporated into the edge seal to absorb water vapor that could enter the airspace.
- Expansion in day — contraction at night due to temperature change causes stress on the seal.
IG Unit and Film
- Window films that absorb too much heat, can cause seal failure and thermal breakage in these units.
- Some IG Units may use inert gases that are heavier than air to reduce convective air movement within the unit to provide uneven better insulation properties.
- Some very dark or metalized films that absorb heat can cause problems with the integrity of an IG Unit. We will discuss this later in the section on glass breakage and IG Unit failure.
- Pass IG Unit to class for them to inspect
- Why are these units more effective in cooler rather than warmer climates.
Other Types of IG Units
- Heat mirrors
- IG Units with film
- Triple or quad pane units
- Heat mirrors are IG units with film suspended between the panes.
- Coating on the film is designed to reflect heat back into the room
- Triple and even quadruple pane IG units are also available, although they are not as popular due to costs.
- Basic – Monolithic
– annealed, heat-strengthened, tempered
- Value added – processes
– Tinted or colored
– Reflective coatings
Wired, textured, patterned
- Basic glass is monolithic single sheet glass in either annealed, heat-strengthened or tempered.
- That glass may go through value-added processing, to change its basic performance characteristics.
- Glass may be laminated with other materials to strengthen and resist impact.
- Glass may be coated to give it Low-E properties.
- Tinted and reflective coatings are applied during manufacturing and have similar performance characteristics to solar control window film.
- It Is Important to understand the relationship of film to glass that has been modified.
- A single sheet of glass of constant thickness.
- Most commonly:
– Heat treated
- Monolithic is the simplest giass construction type.
- It consists of a single sheet of glass of a constant thickness
- Monolithic glass may be annealed, heat treated, or tempered.
- Constructed like a sandwich.
- A filling or interlayer of poly vinyl butyral (PVB) has a layer of monolithic glass on each side.
-Annealed both sides
-Annealed one, other tempered
– Both tempered
- Laminated glass is constructed like a sandwich.
- A filling or interlayer of poly vinyl butyral (PVB) has a layer of monolithic glass on each side. The glass may be tempered or annealed.
- This interlayer tends to hold the broken glass together.
- Laminated glass is the dominate glass of South Florida new construction.
- The more tempered the stronger. To meet Florida buildings codes laminated glass can meet the following condition by combining type of glass with the PVB
- 110 mph wind – no tempered
- 120 mph wind – one tempered
- 130 mph wind – two tempered
- or more PVB
More on Laminated Glass
- The inner layer holds broken glass together.
- Designed to take more abuse.
- Car windshields are laminated glass.
- The dominate glass for new construction In Florida
- Laminated glass is designed to withstand higher than normal loads and impact from snow and wind.
- It is also helpful for noise reduction. Laminated glass provides an effective barrier to entry and reduces the likelihood of flying glass.
- Car windshields are made of laminated glass.
- The new glass of the hurricane belt.
Bullet and Blast Resistance Glass
- Uses multiple laminates of glass or a combination of glass and polycarbonate.
- Only approved film can be used on these types of glass.
- Bullet resistant glass is a type of laminated glass that uses multiple laminates of glass or a combination of glass and polycarbonate.
- The level of protection required determines the ultimate thickness of the glass.
- Even though you will see reports for film making glass bullet resistant — Glass thickness is the key.
- Blast resistant glass is very similar to bulletproof glass with the addition of specifically designed reinforced frames.
- In some case, tempered glass and an “anchored form of window film” may also be considered adequate protection.
- Reflects heat back to the room
- The coating is selective, reflecting longer-wave infrared back into the room.
- Designed for northern climates.
- Usually Low-E coating inside the IG unit surface which surface, not standard
- Low-E glass is a coated or “designed” glass that reflects heat back into the room while admitting visible light.
- Low-E glass is part of an insulated glass unit (double-pane). The coating on the glass is selective passing on the shorter wave visible light into the room. When longer wave infrared energy strikes the window from inside the room, the coating reflects the heat back into the room. The purpose of this is to keeps heat in the room during the winter.
- Basic Low E-windows do nothing to keep the sun out. Low- E windows were originally designed for northern climates. With insulated glass Low-E units up to 32% less heat passes through the window.
- Pass sample
- How does this sample look different from clear glass?
- In the filed, how will you tell if a window is Low-E?
The Surface of the IG unit that has the Low- E Coating is critical to film performance …
- Air Space
- Surface 2 Film Friendly
- Surface 2 Film Un-Friendly
- Desiccant Fill
- Metal Spacer
- Secondary Seal
- Primary Seal
– Color may be either in or applied on glass
– Reduces glare and absorbs heat
– Absorbed heat can be a problem in sunbelt windows
- Originally tinted glass had the color mixed in the raw material before forming into sheets. This method is used it produces glass that is colored consistently throughout its thickness.
- Today, most tinted or colored glass is created by applying the color as a surface coating during manufacturing.
- Tinted glass is designed to reduce glare and absorb heat. The heat-absorbing characteristics of the glass is sometimes exceeded and the heat is then radiated into the cooler room. This type of glass can have significant solar control properties and in some cases reduce a high percentage of ultraviolet transmission.
- Pass three samples of tinted glass
- How do these compare in appearance
- How are they similar to film?
- How are they different from film?
- Reflective coatings
– Metallic oxide on the glass surface
– Reduces heat and visible light transmission.
– Changes the properties of the glass much the same as film.
- Reflective coated glass has a metallic or metallic oxide coating applied onto or into the glass surface to reduce solar heat energy and visible light transmission.
- A wide range of these coatings is available with different visual and infrared transmission characteristics.
- As with film, these glass products offer varying levels of aesthetic appeal, energy savings and occupant comfort.
- Pass three samples of reflective glass
- How do these compare In appearance?
- How are they similar to film?
- How are they different from film
Other Types of Glass
- Wired, patterned, and textured glass are an issue with film and glass breakage
- The manufacturing processes for these types of glass introduces edge flaws.
- Unique types of glass introduce unique issues when adding film.
- Of particular concern is that the manufacturing process associated with these types of glass typically introduces surface and edge flaws that make the filming of these surfaces risky.
- Wired glass is a fire glass – not a security glass and certainly not a safety glass.
- Horrible accidents have occurred with this glass
- This glass doe not meet ANSI Z 97.1
- The addition of 4-mil film makes this glass safer.
- 1/8″ or 3/16″ used for residential windows
- 1/4″ most common commercial glass
- 3/8″ or higher retains more heat
- Various thickness of glass is used in monolithic, IG units or in laminated glass.
- Thickness increases strength.
- Thicker glass retains more heat and will become and issue in our discussion of film and glass breakage.