Mold containment barrier (C) Daniel FriedmanMold Clearance Timing - When to Schedule the Mold Clearance Inspection

  • MOLD CLEARANCE TIMING - CONTENTS: Mold clearance inspection procedures: timing of mold testing after a mold cleanup job; - when to inspect and test a building after mold cleanup. Wait time & other recommendations for mold clearance testing after a mold remediation project. Mold Clearance Procedure Outline: When & How to Inspect and Test after Mold Cleanup. What building areas should be tested? How does a building "pass" a mold clearance inspection & test?
  • POST a QUESTION or READ FAQs about testing & inspecting a building after a mold remediation project

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Mold clearance test details: when to schedule an inspection and testing after a mold cleanup project. Here we explain and describe in more detail the post remediation mold clearance procedures and testing that should be used after a mold remediation or mold cleanup project.

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MOLD CLEARANCE TEST TIMING: When to Inspect & Test a Building After a Mold Cleanup / Remediation Project

This article is part of our ACTION GUIDE which provides an easy to understand step-by-step guide for dealing with toxic or allergenic indoor mold and other indoor contaminants: what to do about mold "mildew," moisture, in your house or office, building-related illness, involving your physician, treatment, sick building investigators, reduction of irritants, and special products to help clean buildings and air.

As we noted at MOLD CLEARANCE INSPECTIONS and CLEARANCE PROCEDURES, the inspection and testing of a building to confirm that a mold cleanup project (mold remediation) has been adequately performed should not be scheduled until

  1. After the mold remediation company has completed all demolition, moldy debris removal, and moldy surface cleanup that are to be performed
  2. After the conditions that caused the mold problem have been corrected (lest we waste the cost of cleanup by having a new mold problem)
  3. After any building air scrubbers or exhaust systems are off for 24 hours or more: equipment used during the remediation project should have been turned off for 24-hours or longer (to allow time for dust settlement indoors). See Sill Air Conditions, below.
  4. Before the mold remediation project containment barriers have been removed. This permits the inspector to evaluate the workmanship of the containment system, its completeness, evidence of failure or collapse. More, this procedure also means that areas of the building outside the remediation work space remain protected against cross-contamination by moldy dust until the inspection and lab work have confirmed that the cleanup was successful. Finally, should the inspection or lab work indicate that more cleaning is needed, this process saves the cost of having to re-install containment as well as the possible cost of having to perform extra cleaning outside of the containment area.
  5. Before the remediation area is re-occupied by people at extra risk from building air quality concerns such as asthmatics, elderly, immune, infants, etc.
  6. While the building remains in still-air conditions: windows and doors to outside are closed.
  7. Building mechanical systems:
    1. If weather conditions permit, the building heating or cooling system should be left off to avoid the risk of re-contaminating those systems before the successful clearance has been confirmed.
    2. An exception may be necessary in cold climates during freezing weather, or in hot humid climates to control humidity.
    3. HVAC systems serving the remediation area, their air handlers and duct work should be included in clearance inspection and testing, and if clearance includes (as we recommend) checking out of the cleanup area for cross contamination, all building HVAC systems should be included in that procedure.

CONTACT us to suggest changes or additions to this mold clearance inspection protocol.

The Role of Still Air Conditions in Post Remediation Mold Clearance Testing

Don't Perform Post Mold Remediation Testing Too Soon

Mold remediation job after cleanup (C) Daniel Friedman24-hours of still air conditions is the minimum time we want to allow for settlement of airborne dust and debris in a buildings before conducting an air or surface dust screening test for mold contamination after a mold cleanup project. Longer dust settlement time is better.

Our photo (left) shows a very clean building basement that has been sealed as well. The air scrubber machine remained in the building but as we asked, it had been turned off prior to our onsite inspection. The containment barriers are not visible in this photo and would need to be verified if only part of the building was being cleaned.

At remediation jobs for which we have been the clearance inspector, we require no less than 24 hours of still air time. The containment is left in place, the air scrubbers are simply turned off. That allows the clearance inspector to evaluate the quality of dust containment that was set up, and if, as sometimes happens, more cleaning is needed, the containment does not have to be put up a second time, thus saving some money.

And allowing settlement time means that if there was poor cleaning, and the air is still contaminated, we can often find that evidence in settled dust - more reliably than may be found by dashing in and simply grabbing a quick "air sample" (We use both methods).

We have rarely encountered a mold remediation company who objected to our clearance protocol - after all, the more confident everyone can be in the quality of the clearance inspection the more all parties are protected, including the mold remediator. In a few cases in which the remediator wanted us to test while their machines were running (and we have done so) once we explain the issues to the client, that has been the end of any debate on time periods.

Don't Perform Post Mold Remediation Testing Too Late

However, to protect the mold remediation company from being blamed for contamination that may have occurred due to subsequent building leaks or events, or from cross-contamination of the mold remediation work area by mold from other building areas that was excluded from the project (not an exclusion that we recommend), we suggest that

  1. The post remediation clearance inspection and test be performed before mold containment barriers have been removed.
  2. The post remediation clearance inspection and test should be performed in not more than five days after the completion of the cleanup project. 24-48 hours is recommended.
  3. The post remediation inspection should include a report of visible or known conditions at the building that present a risk of future leaks, moisture problems, and mold contamination

Post-Mold-Remedation Procedures that are Specifically NOT Recommended Include

Violating any of the conditions described above at MOLD CLEARANCE TIMING above.

Taking Down the Containment Barriers Too Soon

Our photo (below left) was part of compelling evidence that the mold remediation crew at this New York City apartment cleanup job had been inexperienced to say the least. The plastic containment barrier had been removed when we arrived to inspect the building. But we found a number of troubling conditions including

The plastic containment barrier had been "hung" from the fire sprinkler heads using duct tape strips. Good grief. What if during the project someone pulls that down and sets off the sprinkler system, creating a new building flood? What if there is a fire during the project and the sprinkler heads have been tampered-with or blocked? And why was the ceiling cavity left open to receive dust during demolition, transporting it over other areas of the apartment?

Mold containment failure (C) Daniel Friedman Mold containment failure (C) Daniel Friedman

Our second photo (above right) shows that the plastic used to seal around an air scrubber exit port had collapsed - probably not a serious failure at this job.

We understand that it can be costly for a mold remediation company to leave equipment idle at a property while waiting for the post-cleanup inspection, testing, lab work, report, and client approval. But that concern should not extend to early removal of the containment system as well.

The temptation to rip down the building containment system before the inspection and clearance test comes from several thoughts in the remediator's viewpoint:

  • It seems efficient to take down and dispose of containment while the full remediation work crew is still on site - avoiding having to send laborers back to the jobsite after the clearance test
  • The remediation company may be confident (perhaps sometimes overconfident) that their work has been successful
  • The remediation company may not want the clearance inspector to evaluate their containment methods, especially where amateur workmanship have been involved.

By premature takedown of the dust containment system risks costs we introduced above.

  • It prevents the inspector from supporting the remediation company's workmanship on the containment system by direct observation
  • Early containment removal this procedure also means that areas of the building outside the remediation work space remain protected against cross-contamination by moldy dust until the inspection and lab work have confirmed that the cleanup was successful.
  • Finally, should the inspection or lab work indicate that more cleaning is needed, this process saves the cost of having to re-install containment as well as the possible cost of having to perform extra cleaning outside of the containment area.

Leaving the Air Scrubbers Running

Remediators - some - would like you to test while their air machine is running, having the fantasy that even if they didn't remove all the mold they should-have, the scrubber will hide that fact ... until later, after everyone has gone and the remaining mold propagates again.

Sometimes this approach - leaving a scrubber on - allows the remediator to shoot themselves in the foot, especially when the company foolishly did not vent the air machine to the outdoors. In that case if there is problem dust and debris remaining, the machine is simply stirring it up further. You cannot remove an indoor air particle problem by vacuuming the air. As long as the particle source remains there is, in a practical effect, an infinite particle source.

Leaving Building Windows & Doors Open

A second approach that some remediators like is to have the clearance performed while the building is being aggressively ventilated with outdoor air. This too can obscure an in-building remaining mold or particle source problem in or out of the remediation area, and in some conditions can also bring in excessive levels of outdoor pollen or mold. Or moisture, or even rain at an unattended building.

While ventilating a building with outdoor air may work in some cases to help clean up a building interior, it is impossible to distinguish reliably between outdoor conditions and indoor building conditions if the building windows and doors are open 24-hours before or during the clearance inspection.

U.S. EPA Guidance for Mold Clearance Inspection After a Mold Cleanup

Our complete collection of US and international mold standards references are collected at MOLD STANDARDS.

From the US EPA we include this more general advice on the criteria for a mold cleanup job: [Our comments are in brackets]

How Do I Know When the Remediation or Cleanup is Finished?

  • You must have completely fixed the water or moisture problem before the cleanup or remediation can be considered finished. [See MOLD PREVENTION GUIDE]
  • You should have completed mold removal.  Visible mold and moldy odors should not be present.  Please note that mold may cause staining and cosmetic damage.  [See MOLD CLEANUP, VISUAL CHARACTERISTICS and see ACCEPTABLE MOLD LEVEL. Remember that no building is mold-free except perhaps inside of a manufacturing "clean room" - mold exists in air everywhere and small amounts of molds will be found in settled dust just about everywhere - don't set a target of "zero mold".]
  • You should have revisited the site(s) shortly after cleanup and it should show no signs of water damage or mold growth.  See MOLD CLEARANCE TIMING.
  • People should have been able to occupy or re-occupy the area without health complaints or physical symptoms.  [See MOLD RELATED ILLNESS GUIDE.]
  • Ultimately, this is a judgment call [and must include an understanding of the original location, extent, type, and cause of mold contamination that was to be removed as well as the chances of other mold contamination in the building that was not addressed]; there is no easy answer. If you have concerns or questions consult our Frequently Asked Questions database and ask a question [or Contact Us directly at] if you don't find what you need.

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