• Glazing Overview
  • Thermal Performance Data
  • Product Performance
  • Sound Attenuation
  • Powder Coating
  • Reinforcing Mullions

Glazing Performance Terms

U-Factor: U-factor measures how well a product prevents heat from escaping. The rate of heat loss is indicated in terms of the U-factor (U-value) of a window assembly. U-factor ratings generally fall between 0.20 and 1.20. The insulating value is indicated by the R-value, which is the inverse of the U-factor. The lower the U-factor, the greater a window’s resistance to heat flow and the better its insulating value.

Solar Heat Gain Coefficient: Solar heat gain coefficient (SHGC) measures how well a product blocks heat caused by sunlight. The SHGC is the fraction of incident solar radiation admitted through a window, both directly transmitted and absorbed and subsequently released inward. SHCG is expressed as a number between 0 and 1. The lower a window’s solar heat gain coefficient, the less solar heat it transmits.

Visible Transmittance: The visible transmittance (Vt) is an optical property that indicates the amount of visible light transmitted. Vt is expressed as a number between 0 and 1. The higher the Vt, the more light is transmitted.

Condensation Resistance Rating: Condensation Resistance (CR) measures how well a window or door resists the formation of condensation. CR is expressed as a number between 1 and 100. The higher the number, the better the resistance to condensation.

NFRC

NFRC Labeling

All certified Sierra Pacific Windows and Doors are shipped with both a temporary and permanent label affixed to the glass.

The temporary label is intended to remain on the unit through the construction process and provides the consumers, builders and code officials with energy performance ratings in a comparable, easy-to-read format. The label shows the product is NFRC certified, provides a brief product description, and shows the pertinent thermal performance values.

The permanent label allows for manufacturer identification and performance tracking for the life of the product.

NFRC ratings include U-Factor, SHGC (Solar Heat Gain Coefficient), Vt (Visible Light Transmittance) and CR (Condensation Resistance) values for a variety of glass types and divided light options.

Argon gas not available above 4200 feet in elevation. Triple glaze units over 2200 feet in elevation will have vent tubes and NO Argon gas.

Aluminum Clad Windows  |   Aluminum Clad Doors  |   Wood Exterior Windows  |   Wood Exterior Doors

 

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Understanding Product Performance

The functional performance of window and door products is determined through a series of tests which include air/water infiltration and structural wind loading.  Product performance as specified by AAMA/WDMA/CSA/ 101/I.S.2/A440, otherwise known as the "North American Fenestraton Standard/Specification for windows, doors and skylights" (NAFS), is based upon performance class and performance grade assigned as a result of these and other tests.

Performance Class Designations:
For the 2008 edition of NAFS, the C and HC Performance Classes from previous editions were consolidated into a new "CW" Class.  These classes are: 

  • "R" Class, commonly used in one- and two-family dwelling
  • "LC" Class, commonly used for low- and mid-rise multi-family dwellings and other buildings where larger sizes and higher loading requirements are expected
  • "CW" Class, commonly used in low- and mid-rise buildings where larger sizes, higher loading requirements, limits on deflection and heavier use are expected
  • "AW" Class, commonly used in high-rise and mid-rise building to meet increased loading requirements and limits on deflection and in buildings where frequent and extreme use of the fenestration product is expected

 

AAMA/WDMA/CSA 101/I.S.2/A440-08
Windows and Doors


Performance
Class

Minimum Performance Grade (PG)

Design
Pressure,
Pa (psf)

Structural
Test Pressure,
Pa (psf)

Water Resistance
Test Pressure,
Pa (psf)

R

15

720 (15)

1080 (22.5)

140 (2.90)

LC

25

1200 (25)

1800 (37.5)

180 (3.75)

CW

30

1440 (30)

2160 (45.0)

220 (4.50)

AW

40

1920 (40)

2880 (60.0)

390 (8.00)

 

Performance Grade (PG) Designations:
To qualify for a given Performance Grade (PG), one or more representative specimens of the product must pass all required performance tests for the following:

  1. Operating force (if applicable)
  2. Air leakage resistance
  3. Water penetration resistance
  4. Uniform load deflection test
  5. Uniform load structural test
  6. Forced entry resistance (if applicable)

Additionally, these test specimens must pass all required auxiliary (durability) tests for the applicable product type and desired performance class, including such things as hardware load testing.

Optional Performance Grade (PG):
Optional Performance Grades may be specified in each Performance Class.  Sierra Pacific Windows frequently tests to an optional PG.  For example, Sierra Pacific casement windows are tested to PG 40 rather than the minimum requirement of PG 25, for the LC Performance Class, to best reflect the product performance capability.

  Clad Performance Grades

  Wood Performance Grades

Increasing in increments of 5 psf, Optional Performance Grades are capped at a maximum of 100 psf for all Performance Classes except AW, which has no maximum PG.

A typical performance rating would appear as:

Class C-PG 30-H, where Class C = performance class "C"
PG 30 = performance grade 30
H = product type (hung window- vertical sliding)

Product tests and the resulting performance ratings are valid for four years.  Until a product has been retested to the 2008 version of the NAFS standard, it will show a different performance rating based on the previous (2005) standard.

Please contact your Sierra Pacific Windows representative with any additional questions you might have regarding product performance.

Sound Attenuation

Sound attenuation can be an important consideration when choosing windows and doors. Sound Transmission Class (STC) is a method of rating that provides a single value to represent sound transmission loss. While the method is frequently used, it is based on noise reduction achieved over a range of frequencies associated with indoor environment (human speech or office equipment). Outdoor-Indoor Transmission Class (OITC) is actually a better measure of a window's or door's transmission loss because it is based on a range of lower frequency sounds (traffic, trains, aircraft, etc.). Both rating numbers are provided for Sierra Pacific products.

OITC ratings are typically lower than STC ratings because lower frequency sounds are more difficult to attenuate.

 

  Sierra Pacific Windows Sound Transmission Ratings

 

Powder Coating

The coating on Sierra Pacific’s exterior extruded aluminum is a modified polyester powder formulated with a special proprietary resin that offers excellent mechanical characteristics such as hardness, impact resistance, adhesion and flexibility. In addition, our coating also provides outstanding chemical resistance, abrasion resistance and corrosion protection.

These high performance coatings are designed to meet AAMA 2604 specifications and have surpassed the five year South Florida Exposure requirement. AAMA 2605 coatings are available upon request.

  AAMA 2605 Coating Specifications

    Mechanical Durability

  • Higher surface hardness/scratch resistance than common liquid coatings
    • Reduced chance of damage to coating during installation
    • Better longevity against mechanical damage
      • High resistance to cleaners and chemicals
      • High resistance to windborne abrasives

    Superior Exterior Performance

  • High resistance to acid rain and corrosive atmosphere
  • Meets ASTM/AAMA 4,000 hour salt spray resistance testing
  • Meets 4,000 hour ASTM humidity testing
  • High resistance to chalking
  • High resistance to film coating erosion
  • Improved color and gloss retention

  AAMA 2604 Coating Specifications

    Mechanical Durability

  • Higher surface hardness/scratch resistance than common liquid coatings
    • Reduced chance of damage to coating during installation
    • Better longevity against mechanical damage
      • High resistance to cleaners and chemicals
      • High resistance to windborne abrasives

    Exterior Performance

  • High resistance to acid rain and corrosive atmosphere
  • Meets ASTM/AAMA 3,000 hour salt spray resistance testing
  • Meets 3,000 hour ASTM humidity testing
  • High resistance to chalking
  • High resistance to film coating erosion
  • Improved color and gloss retention

Windload Reinforcing Mullions

Need for structural reinforcement
Large mull composites of windows are very popular. Many of these composites are installed in homes and buildings constructed on mountains, canyon rims or oceanside. While these sites provide magnificent views, they also introduce the potential for exposing windows to very strong windloads.

Standard mulling methods of joining window units is more than sufficient for many composites. Under heavy windload situations, however, standard mullion joints could bow (deflect) beyond their design limits. In these situations, it is necessary to consider additional structural mullion reinforcement.

Structural alternatives
Assuming that structural reinforcement is required, there are currently two options. First, the customer can supply his own. He can add additional framing or secure the services of a structural engineer to design specific supports. The second option is to use a structural reinforcement option supplied by Sierra Pacific Windows.

Sierra Pacific Windows offers two structural reinforcement alternatives. The first is a 1/2" narrow aluminum support. This system consists of two symmetrically interlocking aluminum extrusions with end brackets to anchor the extrusions to the framing structure. Since the narrow support widens the mullion joint by only 1/2", there is minimal visual interference. It works with both wood and aluminum clad wood product.

  Aluminum Structural Reinforcement

For higher windload requirements, a second alternative is available. Steel tubing (typically 1-1/2" x 4") can provide support beyond the capacity of the aluminum. Utilizing welded steel plates for anchoring into frame walls, steel tubing provides additional support for larger mull composites. Note that this option will add a minimum of 2-1/4" to the width of the mullion joint.

  Steel Tubing Structural Reinforcement

Either support alternative can be used horizontally or vertically. Sierra Pacific Windows also has mull cover options to complete the installation.