You’ve been there before. You’ve just finished (or thought you’ve finished) a complex mold remediation project only to find that the testing results showed the presence of a previously undetected microbe. Worst yet, it’s a microorganism that could be toxic to your customer and will most certainly jeopardize your clearance. What do you do now? The following items are some additional steps that can be taken to help prevent and/or remedy the problem:
Pre-tests, although costly, can be a critical benchmark in establishing the amount of cross contamination already present before you arrive. Whether it was because of previous remediation attempts, the movement of air, or even the manipulation of contents before you even arrived on the scene, chances are some mold spores have already migrated to other rooms. What a pre-test can tell you is where you’re starting from, and even more importantly, what you have to achieve in order to have a successful remediation.
• Seek advice
As a professional remediation contractor, the most important thing you can do is to seek consultation with an independent testing company. Although an independent pre-test may be optional, an independent post-test is critical – not only for the customer but also for you. After all, not only will they lend credibility to your clearance, but they will also help recommend ways of explaining and overcoming any negative test results. In a cross-contamination situation, they can often be your best ally and primary source of advice. It for this reason alone that you should not only look to work with testing companies that uphold your level of standards, but also consistently resist the opportunity to accept referral fees or “kick-backs”. This will ensure that they have enough integrity leftover to lend to your jobs.
• Start over
Yes, it can be as simple as that. Sometimes the reason that we don’t obtain clearance is because we didn’t do our job right. Provided that the problem now doesn’t extend outside of the original area remediated, you may still have the opportunity to fix the problem before it gets out of hand. Take a moment and review the scene. Was everything that was supposed to be removed actually removed? Was everything cleaned properly? If so, is there a possibility that the wrong items were removed and the affected items still remain? Were all the waste bags cleaned prior to removal? Take care to not only look at what you can see, but also at what you can’t. Have you checked the ceiling tiles? Did you look under the counter? How about in the air ducts? Then, after taking all these steps, regardless of any conclusions made, clean the entire site a second and third time. Better yet, have a second remediation team clean the second time. This will ensure a fresh outlook and a rested eye towards detail.
• Restrict Access
While you may be aware of your crew’s activities on the project, you can’t always predict the actions of the customer or any consultants. Take care to restrict containment access to only those people with the necessary credentials, safety training, and a legitimate need to view the project. For jobs where the containment will be left unattended in the evenings, invest in a lock and clearly mark all exits and entries with signs indicating the restricted access. Not only will this ensure a tight control of the project, but it will also ensure more efficient results.
• Look around
Sometimes a mold problem is not only an indication of a water problem, but also a sign of a larger maintenance issues. Examine whether the mold problem is more of a symptom of the general condition of the premises or workmanship and go from there. If you have a roof problem, you might also want to take a look at the siding and windows as these trades might have been performed by the same sub-contractor. Keep in mind that if one area exhibits poor workmanship, it might be chronic in other trades. If it is a maintenance issue, the range of problems might be even larger. In this case, look for just about every symptom possible. Keep in mind that sometimes the best way to find additional problems is to ask the customer. Make sure to ask about previous water damage problems regardless of their relevance.
• Check your equipment
Although painfully simple, simply checking your equipment may expose the solution to the problem. Was the HEPA filter cleaned or replaced prior to moving it to the next job? Was every tool disinfected? How about the cleanliness of that camera or the moisture sensor you just brought from the last job? Or even the cleanliness of the testing company’s own testing tools and sensors? Are the filters used on the job in good condition and free of any tears or splits? Are you using the correct Personal Protection Equipment – gloves, PPE suits, full-face masks, and boots? Keep in mind that not only does your preparedness and condition of the equipment demonstrate your abilities, but it also saves you from costly mistakes. Take a moment before each job to have a supervisor examine all equipment and general cleanliness prior to the job to ensure constant success. You will be pleased with the results. Who knows, it may even save you from step 1.
• Do the air math
According to virtually all IAQ resources, 4 changes of air per hour are a must for every remediation process. Still, without much work, many remediators commonly exceed 4 changes per hour and typically work in the range of 6-10. While this, by itself, is not a problem, it becomes a problem when you don’t understand where the make-up air is coming from.
In order to better understand this process, it is important to first understand how CFM’s (cubic feet per minute) are calculated. When deciding the amount of equipment necessary, consider the size of the containment. If the containment is 10 feet by 20 feet and 8 feet tall, you can calculate that the cubic feet of this containment is 1600 (10x20x8). With this in mind, you know that in order to have a minimum of 4 changes of air an hour, you need to move 6400 cubic feet of air an hour (1600×4). You can now look at the rating of various negative air machines and make some decisions. If you’re contemplating using a 2000 CFM machine, you know that this machine can circulate up to 120,000 cubic feet of air an hour (2000x60min in an hour). Now, of course a 2000 CFM machine will not actually produce 2000 CFM’s with the proper filters installed, it will probably only deliver 1800 CFM’s. (To confirm the actual CFMs, install a clean filter and check the CFM gauge on the side of the machine.) That’s why in reality; a 2000 CFM machine will probably circulate 108,000 cubic feet of air an hour (1800x 60 minutes). That means that this one machine alone will circulate the entire cubic feet of air within in your containment approximately 67 times an hour (108,000/1600). Obviously, this should be more than enough to conduct remediation activities, but is it too much?
Chances are, it may be way too much. That is, of course, if you do not make the proper accommodations to supply make-up air as well. Just as containment can be compromised by insufficient exhausting, it can also be compromised by inadequate make-up air. Keep in mind that the goal in remediation air management is to obtain 4 changes per hour while keeping a gentle negative pressure in the containment. Certainly 108,000 CFM of exhausting power is more than a gentle negative pressure. At that rate, the containment would collapse on itself and expose the surrounding environment to cross contamination. And even if it doesn’t collapse, any air sampling would be more representative of the outside environment than the containment air.
Simple ways to allow for make-up air to control this problem would be to duct from the outside with the aid of some basic filters covering the supply air ducts (keep in mind that we don’t want to add any more spores than we already have). More complex methods may involve using HEPA exhausting machines in a reverse manner. This provides superior results, as long as the machines are spotlessly clean and have brand new filters. Keep in mind, however, that when you opt for this method, you still need to make sure that negative pressure is maintained. Manometers are wonderful tools for monitoring these pressures and are the mark of a professional remediator.
• Know your molds
Nothing is more important than knowledge. If you want to better understand your options, it is important to understand the mold you are dealing with on each job. Just because an independent testing company claims to know everything about testing doesn’t always mean that they understand microbiology. Make sure that you not only read and refer the reports you receive, but that you also analyze them. Keep in mind, however, that it is not your position to influence the testing company’s conclusions – after all, it is independent for a reason. What you should know is when an additional testing company should be consulted for a third opinion. Ultimately this decision should be the customer’s decision, but as remediation costs increase on each attempt it will become increasingly difficult to ignore this option.
Secondly, carefully read the report. Make sure that it conclusively demonstrates that remediation attempts have met their objective and illustrates it in quantitative results. A good testing report will not only express conclusions, but will also back it up with visual inspection data, moisture readings, as well as spore sampling data. Look for spore sampling data that has adequate control samples from the outside and even a blank slide if your testing company is particularly precise. Know how to read the report and you will know how to exceed their expectations.
Cross contamination problems are certainly not common, but they are normally avoidable with a little bit of attention to detail and preparation. And while this preparation is time consuming, it is certainly less expensive than doing the job twice.