IICRC S520 Condition Reference
The three S520 Conditions (normal ecology, settled spores, actual growth) in plain English.
Reference
Conditions
- Condition 1 (normal fungal ecology) An indoor environment that may have settled spores, fungal fragments, or traces of growth whose identity, location, and quantity are reflective of a normal fungal ecology for a similar indoor environment. This is the goal state of remediation.
- Condition 2 (settled spores) An indoor environment primarily contaminated with settled spores dispersed directly or indirectly from a Condition 3 area. No actual growth, but an elevated settled-spore load.
- Condition 3 (actual growth) An indoor environment contaminated with actual mold growth and associated spores. Growth may be active or dormant, visible or hidden.
Goal of remediation: return Condition 2 and Condition 3 areas to Condition 1.
Checked against published worked examples from: IICRC S520-2024 Condition framework.
Details, formula, and sources
Formula or table(reference page; no compute) IICRC S520-2024 Condition framework: Condition 1 (normal fungal ecology, the goal state), Condition 2 (settled spores dispersed from a Condition 3 area, no actual growth), Condition 3 (actual growth, active or dormant, visible or hidden). Remediation returns Condition 2 and 3 areas to Condition 1. Original plain-English summary; standard text not reproduced.
Source and editionIICRC S520-2024 (Standard for Professional Mold Remediation) Condition framework, by section.
Free accessIICRC S520-2024 licensed; original plain-English summaries free here.
What governsEstimate. AHJ and licensed professional govern.