ANSI E1.2 The video is a brief introduction into the second of ESTA’s American National Standards, now in its third edition. Truss and tower units are the basic building blocks of portable structures. The video outlines what the standard offers: minimum requirements and duties for module manufacturers and users. These requirements are all minimum requirements; doing less would be negligent. The video tells the viewer where to get the standard for free courtesy of ProSight Specialty Insurance.