Definition Of Terms
A Low-E (low-emissivity) coat is a microscopically thin glazing for windows that changes the amount of heat that can pass through them. Low-E coats save money and energy by maintaining a more stable temperature inside buildings, and thus reducing the need for heating or cooling. They can also block UV rays. A high solar gain Low-E coat allows more heat to pass through a window, and is useful for colder climates. A low solar gain coat is appropriate for hot climates because it allows less heat to pass through a window.
Low-E
International Residential Code (IRC- 2006) Section R 310.1 - 310.5
Egress/Rescue Opening Code Requirements for One- and Two-Family Dwellings
Visible Transmittance
U-factor
Solar Heat Gain Coefficient
EMERGENCY ESCAPE AND RESCUE REQUIRED:
R 310.1
Basements and every sleeping room shall have at least one operable emergency and rescue opening. Such opening shall open directly into a public street, public alley, yard or court. Where basements contain one or more sleeping rooms, emergency egress and rescue openings shall be required in each sleeping room, but shall not be required in adjoining areas of the basement. Where emergency escape and rescue openings are provided they shall have a sill height of not more than 44 inches (1118 mm) above the floor. Where a door opening having a threshold below the adjacent ground elevation serves as an emergency escape and rescue opening and is provided with a bulkhead enclosure, the bulkhead enclosure shall comply with Section R310.3. The net clear opening dimensions required by this section shall be obtained by the normal operation of the emergency escape and rescue opening from the inside. Emergency escape and rescue openings with a finished sill height below the adjacent ground elevation shall be provided with a window well in accordance with Section R310.2.
MINIMUM OPENING AREA:
R 310.1.1
All emergency escape and rescue openings shall have a minimum net clear opening of 5.7 square feet (0.530 m2). Exception: Grade floor openings shall have a minimum net clear opening of 5 square feet (0.465 m2).
MINIMUM OPENING HEIGHT:
R 310.1.2
The minimum net clear opening height shall be 24 inches (610 MM).
MINIMUM OPENING WIDTH:
R 310.1.3
The minimum net clear opening width shall be 20 inches (508 mm).
OPERATIONAL CONSTRAINTS:
R 310.1.4
Emergency escape and rescue openings shall be operational from the inside of the room without the use of keys or tools or special knowledge.
WINDOW WELLS:
R310.2
The minimum horizontal area of the window well shall be 9 square feet (0.9 m2), with a minimum horizontal projection and width of 36 inches (914 mm). The area of the window well shall allow the emergency escape and rescue opening to be fully opened. Exception: The ladder or steps required by SECTION R 310.2.1 shall be permitted to encroach a maximum of 6 inches (152 mm) into the required dimensions of the window well.
LADDER AND STEPS:
R 310.2.1
Window wells with a vertical depth greater than 44 inches (1118 mm) shall be equipped with a permanently affixed ladder or steps usable with the window in the fully open position. Ladders or steps required by this section shall not be required to comply with Sections R311.5 and R311.6. Ladders or rungs shall have an inside width of at least 12 inches (305 mm), shall project at least 3 inches (76mm) from the wall and shall be spaced not more than 18 inches (457 mm) on center vertically for the full height of the window well.
BULKHEAD ENCLOSURES:
R 310.3
Bulkhead enclosures shall provide direct access to the basement. The bulkhead enclosure with the door panels in the fully open position shall provide the minimum net clear opening required by Section R 310.1.1. Bulkhead enclosures shall also comply with Section R 311.5.8.2.
BARS, GRILLS, COVERS, AND SCREENS:
R 310.3
Bars, grills, covers, screens or similar devices are permitted to be placed over emergency escape and rescue openings, bulkhead enclosures, or window wells that serve such openings, provided the minimum net clear opening size complies with Sections R 310.1.1 to R 310.1.3, and such devices shall be releasable or removable from the inside without the use of a key, tool, special knowledge or force greater than that which is required for normal operation of the escape and rescue opening.
EMERGENCY ESCAPE WINDOWS UNDER DECKS AND PORCHES:
R 310.5
Emergency escape windows are allowed to be installed under decks and porches provided the location of the deck allow the emergency escape window to be fully opened and provides a path not less than 36 inches (914 mm) in height to a yard or court.Type your paragraph here.
Condensation Resistance
The U-factor is a rating given to a window based on how much heat loss it allows. U-factor generally range from 0.2 (very little heat loss) to 1.2 (high heat loss). The U-factor is the inverse of the R-value of a window, which measures a window’s insulating value. Thus, a high R-value is the same as a low U-factor, and means that a window does not allow much heat to escape.
A poorly-made window cannot get a low U-factor. Single-pane windows are about 1.0 and double-panes are about 0.4. If you live in a colder climate, or find that you are always heating your home, buying windows with a low U-factor is a good way to save energy and money. The National Fenestration Rating Council (NFRC) offers reliable U-factor ratings for windows that they have certified.
The Solar Heat Gain Coefficient (SHGC) is a number assigned to a window that tells you how much heat that window lets pass into your home from the sun. SHGC numbers range from 0 to 1, and the lower the number, the less heat will enter your home. Thus, in hot climates a low SGGC is desirable, while in cold climates a higher SHGC is desirable. The National Fenestration Rating Council (NFRC) offers reliable SHGC ratings for windows that they have certified.
Visible Transmittance (VT) is a measure of how much light passes through a window. VTs ranged from 0 (no light) to 1 (all light). VT is an important quality to consider when purchasing a window because sunlight can fade furniture and carpets or damage precious art. Sunlight can also affect the ambience of a room in your home. A special coating on windows call low-E can provide even better protection against UV rays along with great insulation. The National Fenestration Rating Council (NFRC) offers reliable VT ratings for windows that they have certified.
Condensation Resistance (CR) measures how well a window resists the formation of condensation on the inside surface. CR is expressed as a number between 1 and 100. The rating value is based on interior surface temperatures at 30%, 50%, and 70% indoor relative humidity for a given outside air temperature of 0 Fahrenheit under 15 mph wind conditions. The higher the number, the better a product is able to resist condensation. CR is meant to compare products and their potential for condensation formation. CR is an optional rating on the NFRC label.