Frequently Asked Questions
Will window film stop all interior fading?
No. Window film will not completely eliminate fading from occurring. Depending on the type of window film that is applied, window film can reduce fading by up to 90%. It’s important to note there are multiple causes for fading – UV rays, solar heat and visible light and window film can combat all of these threats.
Will window film damage my residential dual pane windows?
As long as your professional installer uses the right type of window film, your dual pane windows should not be affected. FYI, Johnson Window Films provides “How to Avoid Glass Breakage” support materials to all of their dealers.
Does security film prevent the glass from breaking?
No. Security film does an excellent job at holding broken glass together but it cannot prevent the window from breaking if it comes in contact with a severe force (e.g. hurricane, baseball bat blow).
What is window film made of?
Different polyesters are transformed during the manufacturing process to produce a thin, transparent film that adheres to glass when a pressure sensitive adhesive is activated by a mild solution of dishwashing detergent and water.
Do you install window film on the inside or outside of a building?
Window film is typically installed on the interior side of a window. As it is a finished product, is best installed after all other nearby construction is complete. If access to the interior side of the window is difficult to obtain, an exterior application can be performed.
What is the procedure to install window film?
The individual installation steps, assuming a typical interior application, are as follows:
- Prepare window area by placing drop cloths on floor and / or moving nearby furniture
- Thoroughly clean interior side of glass pane and gaskets with a mild solution of dishwashing detergent and water to remove dirt and other residue
- Wet glass with solution
- Place film against glass
- Squeegee to remove excess solution between glass and film
- Trim film to gasket
- "5-way" film edges to ensure film lies flat
- Wipe film to ensure clean finished product
- Remove drop cloths and replace furniture to original positions
Can you apply window film to Plexiglas®?
No. The film’s specially designed adhesive will not adhere to Plexiglas®.
Can you apply window film to tinted / Low-E glass?
Absolutely! You will notice enhanced energy performance from your tinted / Low-E glass windows after installation.
What is the life expectancy of window film?
The life expectancy of window film is dependent upon multiple variables (climate, exposure to sun, etc). The average life expectancy is ten years and beyond; and, many customers have had window film on their windows for over twenty years.
Will my energy costs decrease?
Absolutely! The amount of money saved depends upon the type of film chosen and certain property-specific variables (location, climate, existing energy costs, HVAC system, etc). After obtaining some basic energy unit costs for a given building, we can conduct a Energy Audit to estimate the annual dollars saved by different film types.
Will my furniture fade be reduced?
Absolutely! Furniture / fabric fade is caused by multiple factors. 10% of fading is caused by miscellaneous factors (i.e. fabric color, material, etc). 25% is caused by heat. 25% is caused by visible light. And the remaining 40% is caused by UV rays. Window films can mitigate 90% of the factors that cause furniture / fabric fade.
How do I clean the filmed surface after installation?
Window films may be washed with common washing solutions (no ammonia-based products) thirty days after installation. Abrasive cleaning agents and bristle brushes which would scratch the film can not be used. Synthetic sponges, squeegees, or soft cloths are recommended in addition to the cleaning solution. To maintain your warranty, do not use tape or other adhesive products on the film.
Window Film “Myth vs. Reality”
Myth – Window Film will stop fading of interior furnishings 100%
Reality: While window film does a tremendous job in reducing the amount of harmful UV Rays (up to 99%) and solar heat (up to 83%), it will not completely eliminate the deteriorating effects of the sun, especially over a long period of time. However, window film is significantly better at stopping fading in comparison to untreated glass.
Myth – Window Film will ruin my view
Reality: Although a dark or reflective film may reduce the view from the outside looking into a car, home or office, it does not mean the same optical restrictions apply from the inside looking out. This is due to Visual Acuity where the human eye basically adjusts to its light surroundings and stabilizes sight enabling an unrestricted sight, even when the light transmission has been reduced by up to 80%.
Myth – Security Film is bullet resistant and hurricane proof
Reality: Many companies claim that security window film will protect glass from such extreme forces such as natural disasters and even bullets. The tests conducted often times use ½” glass and multi-layers of security film—both unrealistic situations in today’s market. And “hurricane proof” is a complete misnomer. If a hurricane can rip open a roof, it only makes sense it can destroy a thin piece of glass window as well.
Myth – Anyone can install window film
Reality: Window film installation may look relatively easy but there are many circumstances that could lead to a poor installation. It’s very easy for the film to become contaminated, thus ruining the film and creating dissatisfaction. A professional installer is experienced with many techniques to prevent problems with the film, and ensure a proper and quality installation.
Why Do I need Window Film?
- Decrease Heat - Today's window film is extremely efficient at controlling the effects of solar energy. Window Film can provide up to 82% heat reduction when applied to untreated glass.
- Reduce Fading - Window Film blocks up to 99% of harmful UV rays. This reduces solar heat and helps to protect your valuable interior furnishings from fading.
- Cut Glare - Whatever the cause - direct sunlight, or reflections from snow, water or surrounding windows - there is a perfect window film solution to help reduce annoying glare.
- Enjoy Energy Savings - Areas of extreme sun or shade can cause interior temperature imbalances and climate control issues. Window film can remedy this problem and significantly reduce air conditioning costs.
- Increase Safety - Acts of vandalism, environmental hazard's and unforeseen accidents can cause glass to shatter and become very dangerous. Window Film can act as a "safety net" by holding shattered glass together.
- Enhance Appearance - Whether it's a contemporary look or a uniform design, there are a variety of window film products that can aesthetically complement the appearance of a home or office building.
- It's Fast and Easy - Professional window film installation is quick and simple. There's minimal disruption to your daily lifestyle or work schedule.
Will Window Film Reduce My Utility Bill?
The more windows there are in your home or building, the greater the benefits of installing window film. That is because window film does much more than simply control heat gain or loss; it also improves the safety, security, energy efficiency, and appearance of your building - all at a fraction of the cost of installing special glass.
Unlike drapes and blinds, window film rejects up to 83% of the heat that would otherwise come through the window. That can translate into a savings of about one ton of air conditioning for every 100 square feet of glass exposed to sunlight.
In addition to keeping solar heat out during the summer months, Window Films keep you warmer in the winter months by reflecting manmade heat back into the building. This can reduce heat loss by up to 30% to save you money and improve occupant comfort.
Window films block out 98% - 99.9% of UV light, thus protecting you from the sun's harmful rays and significantly reducing fabric and furniture fade. They also reduce glare to improve your indoor visibility, especially with respect to computer monitors and televisions.
Definitions:
Ambient
The surrounding or encompassing atmosphere.
Annealed Glass
Manufactured by pouring molten glass onto a bed of molten tin which is then cooled, annealed glass is the product that most people think of as "plate" glass. This flat glass product has little residual surface compression and must be handled with care to minimize thermal stress. It breaks into sharp shards when shattered.
Art / Opalescent / Cathedral Glass
Colored translucent glass, often called art glass, opalescent glass, cathedral glass or stained glass, is also produced by the rolling process, but generally in small, batch type operations. There are usually variegated colors within each sheet produced and no two sheets will match for hue. Thickness will vary within a sheet as well as from sheet to sheet. The maximum thickness produced is usually 1/8". When used as a glazing material, art glass should be glazed in the same manner as tinted / heat absorbing glass. Art glass cannot be tempered.
Attachment Systems
Chemical or mechanical restraint systems that improve the performance of security window film during blasts, high winds and smash-and-grab break-ins.
Blast
A temporary change in the gas density, pressure and velocity of the air surrounding an explosion point. If the initial change is discontinuous, it is referred to as a shock wave. If the initial change is gradual, it is known as a pressure wave.
Blast Over-Pressure
The violent rise in air pressure above normal atmospheric pressure (14.786 pounds per square inch).
BTU (British Thermal Units)
British Thermal Units are the amount of heat required to raise the temperature of one pound of water one degree Fahrenheit (1 BTU = 252 Calories).
Clear Glass
Clear glass consists of silica sand with added alkaline salts such as lime potash and soda. It is colorless and has a visible light transmittance ranging from 75% to 92%, depending upon thickness. It constitutes the bulk of the flat glass that is used.
Daylight Application (Installation)
The process of applying window film to a piece of glass from edge to edge. A small untreated area of glass remains, which is referred to as a “daylight gap”.
Drag (Suction)
The negative pressure effect felt on the roar face of a structure as the blast wave moves away from the building.
Emissivity
The ratio of radiant energy emitted by a surface to the radiant energy emitted by a black body of the same temperature.
Explosion
A sudden release of energy resulting in a blast wave.
Figured / Patterned Glass
Figured / patterned glass is produced domestically by the continuous pour process in thicknesses of 1/8" to 7/32". A pattern etched on one or both of the rollers is reproduced on the glass. Colors are available but are extremely limited. This type of glass is frequently called "obscure" or "decorative" glass. The pattern diffuses detail of objects viewed through the glass, it does not obscure them. The degree of diffusion achieved is a function of the pattern and whether the pattern is on one or both sides. Some patterns cannot be tempered for safety glazing use because of their depth.
Float Glass
The float glass process accounts for over 90% of the flat glass presently produced in the United States. In this process, molten glass is poured continuously from a furnace onto a large bed of molten tin. The molten glass literally floats on the tin, spreading and seeking a controlled level in the same manner as water poured onto a smooth, flat surface. In the controlled level seeking process, the molten glass is allowed to spread to width of 90" to 140", depending upon the furnace size and glass thickness being produced. The glass slowly solidifies as it travels over the molten tin. It is then cooled under controlled conditions. Afterward, it emerges as a continuous ribbon of glass at essentially room temperature. The product is now flat, fire-finished, and with virtually parallel surfaces.
Glass Edge Strength
(1) Glass is made to withstand from between 3000 to 5000 psi (210 to 350 kg/cm) of edge stress. (2) When edge stress exceeds edge strength, breakage occurs. (3) Edge strength depends on glass size, thickness, how it is cut, and treatment of edge by glazier. (4) A straight clean edge is the strongest. (5) Damaged edges can reduce edge strength by up to 50%.
Ground Zero
The location at which an explosion occurs.
Heat Strengthened Glass
Heat strengthened glass is fabricated by a process similar to that of tempered glass. Some equipment can produce both. The glass is heated to approximately 1100° F and the cooling process is slower than for tempered glass. The strength developed is about twice that of annealed glass.
Hot Spots
Areas particularly affected by solar radiation and the imbalance of solar energy.
Impulse
The amount of energy generated in an explosion. It can be either positive (impact force) or negative (suction force) energy. Impulse is measured by integration of the pressure / time curve recorded in an explosion.
Insulated Glass
Double insulating glass units consist of two panes of glass that enclose a hermetically sealed air space. The panes are held apart by a spacer around the entire perimeter. The spacer contains a moisture absorbent material called a desiccant that serves to keep the enclosed air free of visible moisture.
Laminated Glass
Laminated glass consists of two or more plies of glass interleaved with clear or tinted polyvinyl butyl (PF). The application of heat and pressure bonds the glass and plastic interlayer into one unit. When laminated glass is fractured, the particles of glass tend to adhere to the plastic, affording protection against flying or falling particles. Some combinations of glass and plastic thicknesses do qualify as safety glazing materials under the criteria of ANSI Z97.1-1984 and CPSC 16 CFR 1201.
Lite
A sheet or pane of glass.
Low-Emmissivity Glass
Low-emissivity coatings (Low-E) reflect that part of the heat spectrum above 3000 millimicrons wavelength that is called "sensible heat". The heat from hot water or steam radiators and the heat from hot air ducts from a furnace are typical examples of this kind of heat. These coatings have high visible light transmission. In fact, they are nearly invisible on the glass. The visible light transmission is typically about 20 percentage points below that of an equivalent uncoated glass. The major attribute of Low-E insulating units is their sensible heat reflecting character which is apparent from their low U-values. Low-E coatings are applied to glass by vacuum processes and by pyrolitic processes.
Luminescent Coefficient
The rate of visible light transmission and shading co-efficient (Ke ratio). This is a relationship between how much heat gain is rejected and the amount of visible light transmittal.
Mirrors
Most mirrors are manufactured by the wet chemical deposition method, although a few, for specialized use, are made by vacuum deposition. Safety mirrors are available to meet various laws and building codes. A mirror made from tempered glass will have the inherent distortion from the tempering process and cannot have the same quality in reflection as laminated ones made from mirror quality annealed float glass. Transparent, or two-way mirrors, are designed to allow vision through from one direction while presenting a mirror appearance from the opposite side. Their major application is to permit undetected observation for study or surveillance in places such as prisons, gambling casinos and psychiatric treatment centers. A difference in lighting level is necessary; in the room to be studied the lighting level should be at least five times greater than the lighting level in the observation room; ten times greater is even more effective. Two way mirrors are not intended for use in exterior walls.
Negative Phase
The portion of a blast wave, also known as "suction phase", whose pressure is below ambient.
Pane
A glass-filled division of a window, door or wall, or the glass itself.
Plate Glass
Plate glass, manufactured by the grinding and polishing process, is no longer produced in the United States, and words referring to it have been eliminated from the ASTM Specification C103685. It has been replaced by the float glass process.
Positive Phase
The portion of a blast wave whose pressure is above ambient.
Reflected Pressure
The amount of pressure felt by an object standing directly in the path of an expanding blast wave.
Reflective Glass
Reflective glass is a clear or tinted glass coated with an extremely thin layer of metal or metallic oxide.
Rolled Glass
The rolled glass process consists of pouring molten glass from a furnace, then feeding it through rollers to produce the desired thickness. The glass ribbon is then cooled under controlled conditions. There are three general types of rolled glass: figured / patterned, wired and art / opalescent / cathedral glass.
Shading Coefficient (SC)
The ratio of solar heat gain passing through a glazing system to the solar heat gain that occurs under the same conditions if the window were made of clear, unshaded, double strength window glass. The lower the number, the better the shading qualities of the glazing system.
Sheet Glass
The Sheet glass process accounts for a very small portion of U.S. glass production. Some imported sheet glass will continue to be used, mainly in thickness of 1/8" and less.
Side-on Pressure
The pressure felt on the sides and top of an object as the blast pressure wave envelops and passes over and around it.
Sill
The horizontal structure that supports the upright portion of a window frame.
Spandrel Glass
Spandrel glass panels are heat strengthened or tempered glasses with a ceramic frit color permanently fused to one of the surfaces. Glass in spandrel areas is not subject to corrosion as are some other spandrel materials. Pleasing aesthetics and economies can be obtained using a single framing system for an entire wall. Glass spandrel panels can also save energy when insulation is placed behind them.
Standoff Distance
Generally speaking, the further you are from a blast, the better your opportunity to survive. Each site should be evaluated to assess its structural strength, window frame type and attachment, and glass type to determine which style of film application would be most appropriate to withstand the blast at a given distance.
Tempered Glass
Tempered glass is fabricated by subjecting annealed glass to a special heat-treating process. The most commonly used process is to heat the glass uniformly to approximately 1150° F, and then rapidly cool it by blowing air uniformly onto both surfaces simultaneously. The cooling process locks the outer surfaces of the glass in a state of high compression and the central portion, or core, in compensating tension. The color, clarity, chemical composition and light transmission characteristics remain unchanged. Likewise, compression strength, hardness, specific gravity, expansion coefficient, softening point, thermal conductivity, thermal transmittance and stiffness are unchanged. The only physical property that changes is tensile or bending strength. Under uniform loading, tempered glass is about four times stronger than annealed glass of the same size and thickness, and is thus more resistant to thermally induced stresses, cyclic wind loading and hail stone impacts. When broken, tempered glass breaks into a multitude of small fragments of more-or-less cubical shape. Therefore, it qualifies as a safety glazing material under the criteria of Federal Standard 16 CFR 1201 and the American National Standards Institute (ANSI) Z97.1-1984, when so labeled and certified. Spots or blotches may, at times, be visible on tempered glass, especially when viewed through polarizing lenses or in certain types of reflected light. The intensity will vary with lighting conditions and viewing angle. This is caused by the strain pattern induced during the cooling stage, and is not inherently a cause for rejection.
Thermal Stress
(1) All glass absorbs energy when exposed to solar radiation. (2) Tinted glass absorbs more energy than clear glass. (3) Occurs when there is a temperature differential between center of glass and shaded edges. (4) The ability of the glass not to break is determined by its edge strength.
Tinted / Heat Absorbing Glass
Tinted or heat absorbing glass is made by adding various colorants to the normal, clear glass batch to create a desired color. The four colors available by the float process are bronze, gray, green and blue. Visible light transmittance will vary from 14% to 83%, depending upon color and thickness. The color density is a function of thickness, and increases as the thickness increases; visible light transmittance will decrease as thickness increases. Tinting reduces the solar transmittance of glass, has little effect upon solar reflectance, and hence increases solar absorption (heat). This explains why heat strengthening or tempering is sometimes required for the thicker tinted glasses. Adding a metallic coating also has the same effect on thinner glasses.
TNT Equivalence
The quantity (Ib / kg) of an explosive material expressed in terms of the equivalent mass of TNT required to generate similar blast values.
Total Solar Absorption
The ratio (percentage) of the total amount of solar energy that is absorbed by glass compared to the amount of total solar energy that hits the glass. This solar energy is neither transmitted through the glass nor reflected back out into the atmosphere.
Total Solar Reflectance
The ratio (percentage) of total solar energy which is reflected outward by glass compared to the total amount of solar energy falling on the glass. (Use of window film can affect this.)
Total Solar Transmittance
The ratio (percentage) of the amount of total solar energy in the entire solar wavelength range that passes through glass compared to the amount of total solar energy falling on the glass. (Use of window film can affect this.)
Transmissivity
The amount of radiant energy transmitted from a radiating object through the atmosphere to a target after reduction by atmospheric absorption and scattering.
U-Value
U-value measures the heat transfer that occurs through the inside and outside surfaces of glass. The U-value is a function of temperature and is expressed in BTUs (sec definition) per square foot per hour per degree Fahrenheit (BTU / sq. ft. / hr. / F°). Better insulation systems, including window film, have lower U-values.
Ultraviolet (UV)
The damaging portion of the solar energy spectrum that causes fading and deterioration to fabrics, furniture and furnishings. UV rays also age skin and cause skin cancer.
Ultraviolet (UV) Inhibitors
Chemical and material elements added to products such as window film and lotions to block and / or filter out varying amounts of harmful UV rays.
Ultraviolet (UV) Transmittance
The ratio of the amount of total ultraviolet solar energy that passes through glass compared to the amount of total UV solar energy that falls on the glass. (Use of window film can affect this.)
Visible Light Reflectance
The percentage of total visible light that is reflected by glass and that can be seen.
Visible Light Transmittance
The ratio (percentage) of the total amount of visible solar energy (usually called light) that passes through glass compared to the total amount of visible solar energy that falls on the glass. (Use of window film can affect this.)
Wet Glaze
The application of silicone sealant or similar liquid-state material around the perimeter of the glass, e.g., a bead of silicone mastic used to bond the film to the glass to the window frame.
Wired Glass
Wired glass is produced on the same equipment as figured / pattered glass. A welded wire netting or parallel wires are introduced into the molten glass just before entering the rolls to embed the wire into the glass. Patterned wired glass has a pattern on one or both sides, and is sometimes called "rough" wired glass. Polished wire glass is produced by grinding and polishing rolled wired glass blanks. Tinted / heat absorbing wired glass is available only as an import. The heat absorbing characteristic in conjunction with the normally poor cut edges and the wire netting can cause a high rate of breakage from thermal stress, especially in non-vertical applications. The major uses of wired glass are in institutional buildings and fire rated windows and doors. All wires must be completely embedded in the glass. Some misalignment of the wires may be noticeable, but this is not considered cause for rejection. Wired glass cannot be tempered.
This section contains answers to some frequently asked questions. To skip directly to a certain section of the page, select the category from below.
Scratched Glass and Scratch Removal
Construction Window Cleaning
Insulated Glass Units (IG Units)
Low-E Coatings
Heat Treated Glass
Scratched Glass and Scratch Removal
Q. What are the most common causes of scratched glass?
A. Workers putting tools on windows, plasterers wiping plaster off glass, painters and texture crews dry scraping glass, untrained window cleaners removing construction debris from glass, and defective tempered glass can all result in scratched glass.
Q. Do metal scrapers or razor blades scratch glass.
A. No. Metal scrapers and razor blades alone will not scratch glass. However, abrasive materials, such as sand or fabricating debris from the tempering process, trapped by a metal scraper or razor blade, can scratch glass.
Q. Can scratches be taken out of glass? Does it matter if it is tempered?
A. Yes. Most single scratches can be removed from glass. It's very difficult to remove scratches over the entire surface of defective tempered glass. If attempted, glass distortion may result.
Q. Can chips be removed from glass?
A. Yes, but we do not recommend that practice. Removing chips requires the removal of significant amounts of glass and often results in severe glass distortion.
Q. How deep of a scratch can be removed from glass?
A. A scratch you can catch your finger nail in can usually be removed. Scratches much deeper than this might result in glass distortion.
Q. Can acid graffiti be removed from glass?
A. Yes. With the proper equipment, most acid graffiti can be easily removed from glass without any destoration.
Construction Window Cleaning
Q. What is construction window cleaning?
A. This type of window cleaning requires the window cleaner to be specifically trained to remove several types of construction debris from the glass without scratching.
Q. What are the most common tools used to remove construction debris from glass?
A. Metal scrapers and razor blades have been the standard for construction window cleaning and remain the proven method to safely remove construction debris from glass without scratching.
Q. What chemicals are used to remove plaster, concrete and mortar from glass?
A. Products with phosphoric acid are commonly used. The acid disolves the cement in the debris and makes it much easier to remove. Beware of any side effects on surrounding stucco and IG seals.
Q. What is used or recommended to wet the window in construction window cleaning?
A. High quality window brushs are used for their ability to spread adequate water without scratching the glass. They help prevent sand from getting trapped between the brush and the glass. Strip washers are also commonly used, but hold less water and carry a higher risk of trapping construction debris, which can scratch glass more easily.
Q. Can steel wool be used to clean glass in a construction enviroment, without scratching the glass?
A. Yes. Steel wool is sometimes used to remove construction debris from glass, but carries a higher risk of scratching glass. If construction debris gets trapped between the steel wool and glass, scratching could result. Also, if steel wool is to be used, use only new steel wool. If rust is present in old steel wool, scratched glass will result.
Insulated Glass Units (IG Units)
Q. What is an insulated glass unit?
A. An insulated glass unit, commonly refereed to as an IG unit, is two or more pieces of glass separated by a spacer to allow air or gas to be sealed between the panes.
Q. How are the surfaces of IG units identified?
A. The surface facing the exterior of the building is surface #1, the surfaces inside the IG glass unit are #2 and #3, and the surface facing the interior of the building is surface #4. (This is an example of a IG unit consisting of two pieces of glass.)
Q. On which surface of an IG unit is the tempering stamp usually located?
A. There is no standard or regulation specifying the location of the tempering stamp.
Low-E Coatings
Q. What are Low-E coatings?
A. Low-E coatings were developed to limit the amount of UV rays in buildings, which aids in the reduction of energy consumption. There are two main types of Low-E coatings, hard and soft. Hard coatings are usually applied during the manufacturing process of glass and are very durable. Soft coatings are usually applied after glass manufacturing and are applied in a vacuum chamber, usually with the sputter coating process.
Q. On which surface of an IG unit are Low-E coatings applied?
A. Soft coatings are located inside the insulated glass unit, on surface #2 in warm climates and surface #3 in cold climates. Hard coatings are usually applied on surface #1 or #2, depending on the application.
Heat Treated Glass
Q. What is heat treated glass?
A. There are two main types of heat treated glass, fully tempered and heat strengthened.
Q. What is fully tempered glass?
A. Usually just called tempered glass, fully tempered glass is a safety glass used in many applications where the possibility of human contact is high. This glass is 4-5 times stronger than non-tempered glass and breaks into very small pieces when fractured. According to Federal Specification ASTM C1048-85, fully tempered glass must have a surface compression of 10,000 psi or more, or a edge compression of 9,600 psi or more.
Q. What is heat strengthened glass?
A. Heat strengthened glass is twice as strong as non-tempered glass and must have a surface compression of between 3,500 and 10,000 psi, or an edge compression of 5,500 and 9,700 psi. Fracture characheristics of heat strengthened glass vary widely from much like annealed glass to similar to fully tempered glass. For this reason, heat strengthened glass does not qualify as a safety glass.
Q. What is safety glass?
A. Fully tempered glass and laminated glass are classified as safety glass.
Q. What is laminated glass?
A. Laminated glass consists of two or more panes of glass with a tough plastic interlayer made of polyvinyl butyral (PVB), bonded together under heat and pressure. Laminated glass is also used as an effective sound control product. Laminated glass is commonly used in airports, sound studios, schools and in houses near freeways to keep away unwanted noise from airplanes, heavy machinery and traffic.
Q. When was safety glass first required in houses and buildings?
A. The base requirements were established by the federal government in 1977 through the Consumer Product Safety Commision CPSC 16 CFR Part 1201.
Q. Where is safety glass usually located in a house?
A. Anywhere glass is more prone to human contact such as doors, windows close to the floor, stair landings and tub/shower enclosures. Check you local building code for details or more specific locations.
Q. How is tempered glass made?
A. Tempered glass must first be cut to the finished size, since it cannot be cut or modified after it is tempered. Then the edges are belt seamed or sanded to remove any sharp edges. Next it is washed to remove all fabricating debris. Finally it is heated to almost 1200°F and then quick cooled, which produces the temper.
Q. How do you know if glass in a window is tempered?
A. All tempered glass windows must have a permanent tempering stamp applied to each piece of glass to signify it is tempered. Click here to view an example of a tempering stamp.
Q. Where is the tempering stamp located on the glass?
A. Tempering stamps are located in the corner of each and every piece of tempered glass. Click here to view an example of a tempering stamp.
Q. Is tempered glass softer than non-tempered glass?
A. No. Tempered glass in not softer or harder than non-tempered glass.
Q. Is the surface of tempered glass rougher or more porous than non-tempered glass?
A. No. Quality tempered glass surfaces are just as smooth as non-tempered glass.
Q. Why are some tempered glass surfaces rough?
A. Poor quality tempered glass commonly has fabricating debris fused to it's surface during the tempering process. This is usually a result of tempering contaminated glass.
Q. Is there a standard for washing glass before tempering?
A. No. But, it is highly advised that all glass be washed prior to tempering to remove all fabricating debris.
Contact Judd Coe
Email juddcoe@msn.com
Office 303-934-8329
Cell 303-520-TINT (8468)
Fax 303-979-3133
