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MPP - Your Playbook to

Reducing the Risk of Legionella

Think of the MPP as a playbook used to guide you in the steps you need to take in reducing the risk of legionella occurring in the cooling tower.  As any good playbook does, it must contain both the offensive and defensive steps you plan to take.  It is important to familiarize yourself with this crucial guide.  Take time to read through your plan and know what the key points are in treating your cooling tower.  When an inspection of the cooling tower occurs, the inspector will refer back to the MPP so it is very important to know where to find things.


Just like in any sporting event, the key to staying in the lead is having a strong offense.  The same rule applies when it comes to reducing the risk of legionella.  The purpose of the MPP is to outline all the offensive steps being taken to preclude a positive result for the harmful bacteria that can cause a potential problem.  At the start, a risk assessment should be conducted on the cooling tower system to identify any potential problem areas.  Next, the process control measures must be established.  Included in this are the tower cleanings (to be performed twice each year), weekly testing and inspection of the tower system, quarterly compliance inspections and routine maintenance and part replacement.  The MPP must state exactly what will be accomplished during these visits.  The MPP must also show how the bacteriological and legionella culture testings will be performed and with what frequency.  It is also required that the MPP contain the manufacturer’s specifications for the tower, a flow diagram of the cooling tower system and the chain of command for communication.  There are other items that will need to be covered and/or have samples as part of the MPP, including but not limited to: safety data sheets, copies of service and inspection reports, pesticide and product licenses and safety precautions.


As any strategist will say, your offense is only as good as your defense.  While staying ahead of legionella is the goal, what happens when it is detected?  The MPP also must contain the defensive steps that will need to be taken when a test comes back indicating a presence of legionella or heterotrophic bacteria.  There are four (4) levels of results for both of these testing protocols.  Each has its own specific process that must be followed, ranging from maintaining the current water chemistry and biocide levels all the way up to immediate disinfection within a very tight time frame and retesting the water until results show the tower has been brought back into compliance.  We have found it to be helpful to include a table for both test protocols that show exactly what steps each result will generate.  The MPP must spell out these corrective actions in detail so that an owner can show they are working to keep and/or restore their tower to compliance as specified in the regulations.


As in any game, the ultimate goal is to stay in the lead.  Inspectors, much like referees, are watching to make sure owners are following all the rules as laid out in the regulations.  When you stray from these rules, a warning flag is thrown and penalties are assessed.  The goal is to reduce these occurrences and the resulting fines.


We understand that it is a very time-consuming project to get your MPP in place.  As one of our services to cooling tower owners, NuChem is pleased to offer our assistance in preparing this document for you.  Call and speak with one of our representatives today.  You’ll be glad you did!

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