1. SALT SPRAY TEST:
THIS IS A TEST DEVELOPED BY THE AUTO INDUSTRY FOR SALT CORROSION. HISTORICALLY, THIS WAS CAUSED BY WINTER ROAD SALTING. IT HAS BEEN EXPANDED AS A GENERAL ALKALINE TEST. THE STANDARDS ARE PRESCRIBED IN ASTM B117.

2. KESTERNICH TEST:
THIS IS A TEST DEVELOPED ORIGINALLY IN GERMANY FOR THE VOLKSWAGEN COMPANY. THEY SAW A NEED FOR CORROSION TESTING WITHIN THE ACID RANGE. THIS HAS BECOME AN ACCEPTED TEST OF CORROSION RESISTANCE FOR PRODUCTS IN THE BUILDING MATERIAL TRADE, AND IS THE CORROSION TEST CHOSEN BY FACTORY MUTUAL TESTING LABS. THE STANDARDS ARE PRESCRIBED IN DIN 50018.

ALTHOUGH SALT SPRAY TESTS ARE GENERALLY USED FOR COMPARISON PURPOSES, THEY DO NOT TAKE INTO ACCOUNT THE ACIDS INTRODUCED INTO PRESSURE TREATED LUMBER (CCA) OR NATURALLY-OCCURRING ACIDS IN REDWOOD OR CEDAR (TANNIN). THE KESTERNICH TAKES THE ACIDIC PART OF THE APPLICATION INTO ACCOUNT.

3. ASYMMETRICAL THREAD:
THREAD ANGLES ON STANDARD DECKING SCREWS ARE A SYMMETRICAL 60 DEGREES. AN ASYMMETRICAL THREAD REDUCES THIS ANGLE TO 45 DEGREES, WITH 10 DEGREES ON TOP OF THE THREAD, AND 35 DEGREES ON THE BOTTOM ANGLE. THE RESULT IS A THREAD WITH A MORE "KNIFE-LIKE" EDGE THAT CUTS INTO WOOD EASIER, DOESN'T DISPLACE AS MUCH WOOD, AND HAS A FLATTER TOP ANGLE FACING TOWARDS THE SCREW HEAD. THE BENEFITS ARE LOWER DRIVING TORQUE, LESS WOOD SPLITTING, AND INCREASED PULL-OUT.