TL;DR
An ignition barrier is the minimal protective covering building codes allow over spray foam insulation in attics and crawl spaces entered only for service, slowing the foam's involvement in a fire long enough to matter. Acceptable materials include 1.5-inch mineral fiber, 1/4-inch plywood, or intumescent coatings tested for the purpose, a lighter standard than the 15-minute thermal barrier such as 1/2-inch drywall required where spaces are habitable.
What it means
An ignition barrier is the minimal protective covering building codes allow over spray foam insulation in attics and crawl spaces entered only for service, slowing the foam's involvement in a fire long enough to matter. Acceptable materials include 1.5-inch mineral fiber, 1/4-inch plywood, or intumescent coatings tested for the purpose, a lighter standard than the 15-minute thermal barrier such as 1/2-inch drywall required where spaces are habitable. Inspectors check for it wherever foam remains exposed, and uncoated foam is a common correction item.
Where it sits in the glossary
Ignition barrier is part of the Trade jargon group inside the ProFix Directory glossary. Browse every term in this category from the glossary index.
Why Ohio homeowners should know it
This is a term Ohio homeowners encounter when reading contractor quotes, hiring paperwork, or inspection reports. Understanding it well enough to ask one good follow-up question is usually all the protection a homeowner needs.
ProFix Directory keeps definitions short on the index page and saves the longer context — Ohio-specific rules, where the term comes from, and which ProFix tools touch it — for these per-term pages so the term is easy to cite and easy to share.
ProFix tools that touch this term
See also
License: CC-BY-4.0 — quote freely with attribution to ProFix Editorial Team / ProFix Directory.