Specification conflicts and design resolution · Lesson 2 of 4

Specification conflicts and design resolution: materials, standards and design constraints

How code text changes by edition, what ES-1 and ED-1 are for, where two public guide specifications give different joint spacings and wind statements, why a gauge number is not a thickness, and which metals conflict.

You will be able to: Tell a code requirement from a test standard, a design standard, a guide specification, a manufacturer rule and AFS practice; read an edition correctly; and spot where published values for the same item disagree.

17 min · 12 slides · 16 questions

All lessons in this module

Slide 1 of 12

Code text moves by edition

In IBC 2006 and 2009, section 1504.5 required edge metal on low-slope membrane roofs, except gutters, to be tested for resistance per ANSI/SPRI ES-1.

The 2012 text names Test Methods RE-1, RE-2 and RE-3 of ES-1.

IBC 2021 renumbered the requirement 1504.6 and covers metal edge systems, except gutters and counterflashing, on roofs under 2:12.

Sources

Perimeter Edge Metal Systems for Low-Slope Roofing (presentation file uploaded October 2023) - SPRI (Single Ply Roofing Industry)

Videos for this lesson

What this video shows: A metal roofing supplier's short video on galvanic reaction when dissimilar metals touch in moisture, with copper, steel, aluminum and fastener examples and ways to prevent it.

Video: Mixing Metals on a Metal Roof? How Galvanic Reaction Causes Roof Failure by The Metal Roofing Channel, on YouTube. Chosen from the video's published description.

Glossary

ES-1: ANSI/SPRI/FM 4435/ES-1, a test standard for resistance of roof edge systems to simulated wind on low-slope roofs (2:12 or less). It covers copings and edge systems, not gutters, and does not address weathertightness.
ED-1: SPRI's design standard for edge systems used with low-slope roofing, written because ES-1 became only a test standard. The October 2025 revision discussed here is proposed, not approved.
Edition: The year of a code or standard that a project cites. Code text and standards change by edition, and a section number can point to different text in different editions.
Expansion joint spacing: The largest distance allowed between expansion joints in a run of sheet metal. Public guide specifications give different values: UFGS 32 ft and VA 18 ft for aluminum.
Gauge and thickness: A gauge number is a label, not a thickness: tables can give different decimal inches for the same gauge (stainless does), so a specification should state the thickness in inches and the table used.
Dissimilar metals: Two different metals in contact where moisture is present. The MCA bulletin says copper has a very severe corrosive effect on steel, aluminum and zinc.