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Reflections from 2018 Year End Reporting – Part 1: Validation Sequence Impact on Data Validity

Posted: February 21st, 2019

Authors: Matt C. 

Welcome to the first of a five-part blog series hosted by ALL4’s Continuous Monitoring Systems (CMS) Practice Area.  Each blog will look back at some of the key technical issues that our team encountered while completing CMS reports for the second half and fourth quarter of 2018 reporting periods.  In Part 1, we focus on a topic that seems to come up quite frequently for us across industries and CMS of all types – that is, the impact a validation sequence has on CMS data validity.

If you are familiar with CMS, the idea of a validation (sometime referred to as “calibration”) sequence is not foreign to you.  If you aren’t, then let’s quickly review.  Continuous Monitoring Systems often consist of multiple analyzers (or monitors) that link together to produce data for compliance demonstration purposes.  Each of the analyzers in the system are typically validated (checked for accuracy) on a regular basis (or after a maintenance activity), and the analyzer validations are completed in sequence.  For example, a carbon monoxide (CO) analyzer validation may be followed by an oxygen (O2) validation.  So how does the validation sequence impact the validity of the data recorded by the system?

Well, validations take time to run, and the data collected during a validation is not valid and is excluded from hourly compliance averages.  The applicable regulation stipulates the minimum amount of valid data points needed to calculate a valid hourly average during maintenance or validation hours.  The timing of the validation sequence could prevent the minimum amount of valid data points from being collected within an hour, resulting in invalid hourly averages that need to be unnecessarily reported as downtime.  In other words, the CMS could be accruing avoidable invalid data that decreases the overall monitor availability for the reporting period.  This issue is sometimes compounded because the validation sequence timing can affect the data validity for multiple CMS.  An example of this might be an O2 analyzer relied upon by a corrected concentration emission limitation (ppmvd @ 15% O2) continuous emissions monitoring systems (CEMS) at a facility, such as CO and/or nitrogen oxides (NOX).  The timing of the O2 analyzer’s calibration could be the cause of invalid hourly compliance averages for both the CO and NOX corrected concentration emissions.  This can be further complicated by the time associated with the validation of other analyzers preceding or following in the validation sequence, such as sulfur dioxide (SO2).

We encountered multiple examples of this while completing CMS reports this past month, and successfully worked with our clients and supporting vendors to adjust the validation sequence (and sometimes even the recommended blended validation gases) to maximize data availability for our clients.  Maximizing data availability is important for ALL4 and our clients to avoid any potential penalties or fines because of federal and state data availability requirements.  If you have questions about validation sequences at your facility, or any other aspects of CMS, please reach out to me.  I can be reached at (610) 933-5246 extension 139, or at mcarideo@all4inc.com.

Don’t forget to read Part 2 this five-part blog series on how ancillary analyzers can affect CMS data validity!  To ensure that you do not miss out on the action, signup below for our 4 The Record articles to receive timely updates of current hot issues, as well as in-depth articles that highlight important regulatory topics.


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