MCA conducts many technical studies and research projects in partnership with member and industry partners. These studies include bulletins, white papers, manuals and reports that ensure that metal is at the forefront of innovation, and proactive with codes and standards.
This white paper is published to clarify to the architectural and design community the key principles and background information employed in Drained / Back Ventilated or Pressure Equalized Rain Screen wall systems. It is also available as a resource to the General Contractor, Code Official or Owner communities to explain how the design properties of these two systems accomplish water infiltration management and prevention.
While the building and fire codes are primarily concerned with structural and fire performance of single-skin architectural metal wall panels, there are often other performance indicators used within the construction industry to define an acceptable application. Single-skin architectural metal wall panels are most often defined as those metal sheets and coils that are natural metals (copper, zinc, etc.), stainless steel, or coated-metals that have a surface layer added (painted, dipped, plated, etc.) to a metal substrate. Visual appearance is often defined in architectural specifications that are based on code requirements, architectural requirements, and appearance goals that are beyond the scope of the code. This document states the unified position of the Metal Construction Association and its members with regards to visual acceptance parameters.
The truth is that there are any number of combinations for installation and fabrication tolerances for preformed metal used in roofing and wall construction. The basic rule of thumb is: “Everything should look straight when viewed from a distance of 25'. Particular products or applications might require more stringent tolerances to assure performance.”
This document will discuss procedures that have been used by a number of MCA members for many years. This information is primarily derived from the Preformed Metal Wall Specification Guidelines that was developed in the 1990’s to address a series of topics important to the preformed metal wall industry.