Section Contents:

Relevant standards
Code information

Relevant standards. Select and specify vinyl siding that has been certified through the VSI Vinyl Siding Certification Program. This program allows manufacturers to certify, with independent third-party verification, that their products comply with ASTM D3679, the accepted industry standard for quality. VSI sponsors the program to assure specifiers and consumers of consistent performance attributes in their vinyl siding products.

Through the VSI Vinyl Siding Certification Program, an independent testing laboratory - Architectural Testing, Inc. - reviews the manufacturer's quality control program and performance test results, and conducts unannounced plant inspections twice each year, performing a dozen different quality checks on samples of each certified product. The repeated, consistent application of these rigorous quality tests ensures the success and validity of the certification program.

ASTM D3679 Testing Requirements
Test Purpose Process
Length and Width Ensures siding meets the advertised length and width Length: Average the length at three places on the siding

Width: Measure only what will be exposed once a piece is installed
Thickness Ensures siding meets the advertised thickness (and is a minimum of 0.035" thick) Measure, in thousandths of inches, in five or more places on the siding
Color Ensures uniformity and accuracy of color to manufacturers' specifications at the time siding is produced Reflect light off a piece of siding as an instrument "reads" the color
Gloss Ensures a consistent level of gloss on the siding, per manufacturers' specifications Measure the reflection off several different pieces of the same brand
Camber Measures the straightness of the siding Lay siding flat against a straightedge and measure any difference; cannot be more than 1/8"
Heat Shrinkage Measures the shrinkage that occurs after siding is extruded Place in a hot air oven or water bath (160 F); should not shrink by more than 3 percent
Linear Expansion Ensures siding will not buckle under extreme temperature changes Freeze then heat a small piece of siding (-22 F to +54 F); measure expansion and contraction
Surface Distortion (also called "oil canning") Ensures siding will not bulge, wave, or ripple in the heat Heat a piece of siding on a wall to 120 F and inspect
Impact Resistance Ensures siding will withstand nailing or cutting during installation Drop an eight-pound weight on a piece of siding with a force equal to 60 inch-pounds; should not crack or tear at point of impact
Windload Resistance Tests siding's ability to stay on the wall in heavy winds Subject siding on a wall to low-grade hurricane winds (80 mph)
Weathering Performance Ensures siding retains uniform color over time without chipping, cracking, peeling, or flaking Test pieces outside in various climates (dry/desert, cold/wet, and hot/humid) for two years

Currently, all of VSI's siding manufacturer members - the vast majority of the industry - offer certified product lines. Specifiers and consumers can identify certified vinyl siding products by the label shown to the right. For a current listing of all certified products, which are available in many different styles and brands, please visit VSI's website at

Code information. Vinyl siding and accessories are approved for use by all three national model building codes - the Southern Building Code Congress International (SBCCI), Building Officials and Code Administrators International, Inc. (BOCA), and the International Conference of Building Officials (ICBO). Local and regional code bodies may also have codes governing the use of vinyl siding in their area of jurisdiction, so it's always important to check with all code bodies that exert influence over a project. Although local codes can be found that restrict the use of vinyl siding due to historical concerns, weather conditions or other factors, most cities and communities welcome the use of vinyl siding. In fact, even locales with very hot summers, frequent hailstorms or hurricanes, such as Dade County, Fla., accept many vinyl siding products. Performance tests have verified that some vinyl siding products can even withstand wind speeds of 155 mph or more, which can be found in Category 5 hurricanes. Vinyl siding cannot be used, however, on buildings higher than 50 feet.