Integrity Windows - both Wood Ultrex and All Ultrex - have options for certified mulls. See below.
All (IZ3) assemblies are certified to perform at Design Pressure (DP) level of the lowest rated unit in the assembly*, meeting Air, Water, and Structural requirements per AAMA 450-06. Stepped mulls are not currently available. Assemblies that are factory mulled by Integrity will carry the AAMA 450-06 certification. Field mull kits are available but are not certified.
* Some exceptions apply to particular assembly DP ratings. Please see your local dealer for additional details.
Structural and Standard (frame-to-frame) Wood Ultrex mulls are not certified and do not carry a performance rating.
All Ultrex Reinforced Mull Options or (MRF) mulls are available on all current configurations within the standard All Ultrex minimum & maximum mulling guidelines. The MRF mull is rated to a PG40 per AAMA 450-010 Option 1. The PG rating for the overall assembly will be dependent on the lowest performing member (window, door, or mull). Field mull kits are available but are not certified.
Standard (frame-to-frame) All Ultrex space mulls are not certified and do not carry a performance rating.
Please consult your local dealer for additional information.
For more information, see:
What are the mulling guidelines for Integrity product?
Does Integrity offer a transom window?