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Mold Risk KPIs

Read this article to find out how Conserv's mold risk KPI helps you interpret the environment in your spaces and take action.

Conserv cloud is a free, cloud-based environmental monitoring tool. You can create an account at https://app.conserv.io.

KPIs should help us answer the simple question "How are we doing?" -- read more about our KPI philosophy in our article "Understanding Preservation KPIs".

Take the example of the temperature and relative humidity chart so common in environmental monitoring reports.


This chart does very little to evaluate the risk of mold in your collection.

What if instead of the typical chart you could tell your team, "During most months our mold risk has been "Low" but over the last 30 days the mold risk has gone up to "High".

With an immediate sense of "How we're doing?" your team can then visually assess any mold risks based on data and work with the facilities team to improve the environment.

The mold risk calculations

To calculate mold risk we have to understand the cumulative impact of many temperature and relative humidity readings over time.

Mold risk increases as the favorable conditions for mold growth persist over time, and mold risk decreases the more time spent in unfavorable conditions for mold.

As a rule of thumb, mold spores start to germinate above 65% RH, so one approach to handling mold is to keep the RH below the 65% level. (Note that other factors may also affect the risk for mold growth, such as airflow and history of past growth).

We start by calculating a mold risk score based on temperature and relative humidity for each sensor reading, one at a time.

When a reading shows unfavorable conditions for mold we assign a score of 0. When a reading shows favorable conditions we assign a score between 0 and 1 based on the severity.

We add these numbers up to get the mold risk score (table below). As the number increases from 0, mold risks increase, and once the number gets over 1 it's likely that mold is active.

Mold Risk Score Mold Risk Status
0 None
0 - 0.50 Low
0.50 - 1.00 Medium
1.0 High
> 1.0 Active

Importantly, if the conditions have been unfavorable for mold for 24 straight hours, we reset the mold risk score to zero.

The Conserv mold risk score is loosely based on the logic used by the Image Permanence Institute.

Be good to your future self and team by visually documenting mold with the Conserv observations feature - How to create an observation


Here's an example of a space that likely has active mold - it would be very difficult to eyeball this from the chart. The mold risk score quantifies our risk at a glance.


What's next

With the mold risk KPIs you can get your team aligned on "how are we doing?" and begin to lead the conversation on what needs to be done to improve your collection.

The primary purpose of good metrics is not just to answer questions; Good metrics also help your organization ask better questions to address the root cause of problems.