Remediation
Mold remediation equipment, and what not to use (S520)
In plain English
Structural remediation is the part of a mold job that deals with the building itself, not contents or HVAC. Before it starts, the S520 says lead and asbestos take precedence and "shall" be handled under the law, and if load-bearing or other structural parts are damaged enough to come out, a qualified structural engineer "shall" be involved. Equipment must meet safety and inspection laws and be used according to the manufacturer's instructions and label directions, by workers trained to use it.
Inspection and monitoring tools (thermo-hygrometers, thermal cameras, moisture meters) should be used the same way in the same spots throughout the job so readings compare. Material moisture readings are compared with dry materials of the same kind; temperature and humidity are recorded inside and outside the work area before and during the job, with steps taken if conditions favor growth; and anything a thermal camera flags should be confirmed another way, such as a moisture meter. Pressure and containment should be monitored regularly (a manometer, the direction the plastic bows, or smoke), starting before any material is disturbed and continuing until the post-remediation evaluation or verification shows the contamination is gone.
Air filtration devices are used to create negative pressure or scrub the air, should be HEPA-filtered and leak-tested so all air passes through the filter, and their exhaust airflow is best checked with an anemometer. The S520 says to change pre-filters with the unit running; change HEPA filters away from the job where a release won't matter; recheck the unit after a filter change, a drop, damage or use in wet conditions; HEPA-vacuum and damp-wipe it before the final evaluation or before containment comes down; make sure its exhaust doesn't put anyone at risk; and seal the intake before moving it.
Dust should be captured at the source with shrouds and vacuums on demolition tools. HEPA vacuums should be used throughout, checked each shift, bagged or sealed for transport, serviced where a release can be contained, and never swapped for a shop vac or household vacuum. Misting is for suppressing dust only, works better with a little surfactant or detergent in the water, needs care so it doesn't add moisture, and the settled residue must be wiped or rinsed off.
What not to use, according to the S520: misting or fogging disinfectants, oxidizers, sanitizers or stain removers to kill mold instead of removing it; and ozone or any biocide delivered as a gas or vapor to kill mold, or as a substitute for removal. That includes stand-alone use of hydroxyl generators, UV lights, photocatalytic oxidation, fogged enzymes or diffused essential oils in place of physically removing the mold. Any antimicrobial device "shall" be registered with the authority having jurisdiction. Generators, heaters, water heaters and temporary air conditioning brought onto the job must meet codes.
Key points
- Lead and asbestos first; a structural engineer for load-bearing removal.
- Same meter, same spots; confirm thermal-camera findings with a moisture meter.
- Monitor pressure from before demolition until the area passes.
- HEPA, leak-tested air scrubbers; seal the intake before moving them.
- HEPA vacuums only, never a shop vac or household vacuum.
- No ozone, fogging, UV, hydroxyl or essential oils in place of removal.
Official text
This topic is covered in our own words because the standard behind it is copyrighted; we cite it below rather than reproduce it.
Citations
- IICRC S520, ANSI/IICRC S520 Standard for Professional Mold Remediation — Secs. 9–9.1.8, structural remediation, equipment and tools, inspection and monitoring tools, air filtration devices, source capture, HEPA vacuums, misting, ozone and antimicrobial devices, supplemental systems, pp. 44–46. Best practice