Water passing through the window/door and curtain wall from the exterior to the interior is called water penetration. As per ASTM E1105 water penetration test, a water spray rack system is placed on the exterior side of the test specimen, and a positive air pressure difference is applied to the system. This set up simulates a wind driven rain event on the curtain wall to check for field performance of the product and of the installation. TTS performs valuable role in performing the water penetration test for exterior windows/doors and curtain wall of various building according to ASTM E 1105.