Mould Investigation Tool

How to use

Enter the site details, visible mould area, material type, and moisture status. If air sampling data is available, enter it in the optional section. Press Calculate to determine the IICRC contamination condition, EPA remediation scope, and required worker protection level.

Contamination details

Visible mould area

Total surface area affected by visible mould growth or suspected contamination

m²

Distribution

Spatial pattern of contamination across the building or area

Material type

Substrate on which mould is growing

Moisture source status

Current status of the moisture source driving mould growth

Mould visible to naked eye

Confirmation of visible growth or staining during inspection

Musty odour present

Presence of mould-related odour in the affected area

Air sampling (optional)

Air sampling available

Check if laboratory spore-trap or culture air sampling results are available

Enable

Reference guide

This tab summarises the IICRC S520 (3rd Ed.) condition definitions, EPA remediation scope levels, and worker protection requirements. Use alongside the Investigation Assessment tab for a complete mould investigation record.

IICRC S520 condition definitions

Condition	Definition	Key indicators
Condition 1 Normal fungal ecology	An indoor environment that may have settled spores, hyphal fragments, or traces of actual growth whose identity, location, and quantity are reflective of normal fungal ecology for a similar indoor environment.	No visible growth; no abnormal odour; spore counts consistent with outdoor baseline.
Condition 2 Settled spores	An indoor environment that is primarily contaminated with settled spores that originated from a Condition 3 environment, and which may or may not contain traces of actual growth.	Elevated indoor spore counts; staining or discolouration; recent moisture event with resolved source.
Condition 3 Actual growth	An indoor environment contaminated with the presence of actual mould growth and associated spores. Actual growth includes growth that is active or dormant, visible or hidden.	Visible mould colonies; active or recent moisture source; atypical species detected; widespread distribution.

EPA remediation scope (EPA 402-K-01-001)

Level	Affected area	Recommended contractor	Key controls
Level I Small	< 0.093 m² (< 1 ft²)	Occupant self-remediation possible	HEPA vacuum; damp wipe with detergent; no containment required; N95 minimum.
Level II Small-medium	0.093–0.93 m² (1–10 ft²)	Building maintenance staff (trained)	Mini containment; seal affected area with poly sheeting; HEPA vacuum and damp wipe; PPE required.
Level III Medium	0.93–9.3 m² (10–100 ft²)	Trained remediation professional	Full containment; negative air pressure; HEPA filtration; decontamination chamber recommended; bag-and-tag waste disposal.
Level IV Large	> 9.3 m² (> 100 ft²)	Licensed mould remediation contractor	Full containment with decontamination chamber; negative pressure HEPA units mandatory; licensed contractor; clearance testing required post-remediation.

Worker protection levels (IICRC S520)

Level	Conditions / area	Respirator	Coveralls	Gloves	Eye protection
Level I	Condition 1/2; non-porous; small area	N95 disposable	Not required	Nitrile gloves	Safety glasses
Level II	Condition 2; porous; < 3 m²	Half-face respirator with P100 cartridges	Disposable coveralls	Nitrile gloves	Goggles or face shield
Level III	Condition 3; OR area 3–10 m²	Full-face P100 respirator or PAPR	Disposable Tyvek coveralls	Inner and outer gloves (double glove)	Full-face respirator or goggles
Level IV	Condition 3 AND > 10 m²; OR atypical species	Full-face PAPR or supplied-air respirator	Tyvek suit with hood and boot covers	Double gloves (inner nitrile, outer heavy-duty)	Full-face respirator

Standards referenced: IICRC S520 Standard and Reference Guide for Professional Mold Remediation, 3rd Edition; EPA Mold Remediation in Schools and Commercial Buildings (EPA 402-K-01-001); AIHA Recognition, Evaluation and Control of Indoor Mold (2008). Area thresholds are indicative — professional judgement is required for complex or atypical cases. All remediation should be preceded by identification and correction of the moisture source.