Testing Substantiates FortiFlash® Premium Performance

The International Code Council Evaluation Services has developed standardized acceptance criteria for a wide range of building materials. These acceptance criteria require that a building material demonstrate its ability to perform for its intended purpose through a series of standardized tests. The International Code Council’s AC148 outlines the acceptance criteria for self-adhesive flashing products used for flashing wall penetrations. These acceptance criteria represent the most comprehensive testing regimen against which a self-adhesive flashing product can be measured. That’s why very few self-adhesive flashing products have met the AC148 standards.

Meeting the AC148 acceptance criteria is not mandatory. Yet, it is widely accepted that the AC148 acceptance criteria offers architects, specifiers and builders the most reliable measure of how a flashing product will perform in the field.

The FortiFlash product line has been tested against the AC148 acceptance criteria by a third party testing organization and has met the AC148 standards (see ICC ESR-1591 listed at www.ico-es.org). These tests are noted at right and explained in detail on the back of this sheet.

Additional Testing

In addition to the International Code Council’s AC148 test, there is an additional test that has been designed by the American Society for Testing and Materials (ASTM) to demonstrate the performance of a flashing product when incorporated into a “manufactured assembly” and exposed to adverse weather conditions. Known as the E-331 test, the test determines the resistance of exterior windows and doors to water penetration while simulating wind-driven rain.

The E-331 test completed on FortiFlash demonstrates that the product can withstand wind-driven rain to 50 miles per hour in a wall system.


There are a broad range of self-adhesive flashing products on the market today. Their performance on the jobsite and effectiveness in the wall system varies widely. Before you choose a self-adhesive flashing for your application, you need to know how it performs.

FortiFlash flashing has met the most stringent performance criteria for self-adhesive flashing materials. In addition, FortiFlash has demonstrated performance in thousands of homes as an exceptional protection against water intrusion. Fortifiber is so confident that FortiFlash will perform, that it comes with a 10-Year Limited Product Warranty that provides warranty protection far beyond what other manufacturers make available. See www.Fortifiber.com for details.

AC148 Test Criteria

A) Resistance to UV Exposure

Purpose: To demonstrate that exposure to ultraviolet radiation on the jobsite will not cause deterioration in product performance.
FortiFlash samples were subjected to 21 UV “cycles” by exposing them to UV at 135 to 140℉ for 10 hours per day, followed by conditioning at room temperature for 14 hours – for a 24 hour cycle.

After a total UV exposure time of 210 hours, there was no visible cracking or structural changes such as peeling, chipping, flaking or pitting when observed under magnification.

B) Accelerated Aging – Part 1

Purpose: To demonstrate that repeated exposure to heat will not cause deterioration in product durability.
After the UV exposure cycles were completed, the samples were subjected to accelerated aging when exposed to heat. This involved subjecting them to 25 aging “cycles.” Each aging cycle involved drying the specimens in an oven at 120℉ for three hours with all surfaces exposed, and then immersing them in water at room temperature for 3 hours. The specimens were then blotted dry and air dried for 18 hours at 75℉ with all surfaces exposed.

When the 25 cycles were complete, the samples did not demonstrate any sign of visible damage when inspected under magnification.

C) Accelerated Aging – Part 2

Purpose: To demonstrate that repeated exposure to heat and cold will not cause deterioration in product performance.
A different set of UV-exposed samples was subjected to 25 cycles of accelerated aging when exposed to heat and then cold. This involved drying the specimens in an oven at 120℉ for three hours with all surfaces exposed, immersing the samples in water at room temperature for 3 hours and then placing the specimens at 40℉ for 18 hours.

When the 25 cycles were complete, there was no visible damage, such as cracking or chipping to the specimens.

D) Tensile Strength

Purpose: To demonstrate that the flashing material does not lose durability after exposure to UV.
The tensile strength of un-aged and UV-aged samples was tested using a standard testing apparatus. The results of the test demonstrate that FortiFlash exceeded the minimum tensile strength requirements of AC148.

E) Nail Sealability

Purpose: To demonstrate that the flashing material self-seals around fasteners and is waterproof.
Samples of the flashing material were attached to plywood and galvanized roofing nails were driven through the flashing into the plywood. Each sample was then inserted in a dual-chambered water testing apparatus, so that the sample was immersed from above in five inches of water; and water that passed through the nail penetrations could be measured. The entire apparatus was then placed in a refrigerator for three days.

When the test cycle was complete, there were no signs of water accumulation in the lower test chamber – indicating that the flashing material’s protective capabilities had not been compromised. Nor were there signs of water on the nail shanks, or between the plywood and flashing membrane.

F) Pliability

Purpose: To demonstrate that the flashing material is easy to install, even when exposed to low temperatures.
Samples were refrigerated at 32℉ for four hours. They were then placed under tension and bent 180 degrees around a 1/8″ diameter mandrel.

When examined under a microscope, the samples demonstrated no signs of cracking.

G) Peel Adhesion

Purpose: To demonstrate the flashing material’s long term adhesion performance and durability.
Five new samples and five aged samples were attached to OSB substrate, per the ASTM C794 standard testing methodology. Peel strength tests were conducted on the new samples after a seven day curing period and on aged samples using standard testing machinery. The criterion for acceptable performance is that the aged samples must demonstrate a peel strength that exceeds 75% of the new samples.

All samples tested exceeded the minimum 75% peel-adhesion strength.

H) Water Resistance

Purpose: To demonstrate that the flashing material’s water resistance does not deteriorate with jobsite exposure.
Samples that had been UV-exposed and aged were placed in a testing apparatus that exposed the material to a column of water for a period of two hours. The samples showed no signs of leakage during or after the two hour period.