The procedures for leak detection systems are spelled out in an EPA Guidance Document.  You may download the document using the icon below:

 

   EPA Guidance Document

 

 

 

Baghouse leak detectors are installed as indicators of fabric filter performance.  The results from the leak detectors are NOT meant to be correlated with particulate emission test results.  The results from the sensor are recorded during a representative period of well-controlled emissions and alarm level is set based on those results.

 

The guidance document provides procedures for the initial and periodic setup of the alarm point.  It also contains required on-going quality assurance procedures to make sure that the monitoring system is functioning properly (see below).

 

 

 

 

The EPA Guidance requires that you conduct the following quality assurance checks:

 

   Monthly zero and span electronic drift checks, 
   Periodic probe inspection and cleaning, and 
   Yearly sensor alarm setup 

 

The Guidance Document requirement for monthly checks is shown below:

 

 

 

 

The procedures for conducting the electronic drift checks are highlighted below:

 

 

 

 

 

For some probe systems, these procedures require significant labor by a technician as well as specialized equipment to generate the required signals (pico amps).  The patented PCME DT990 probe conducts these electronic checks automatically and the results are displayed on the operator interface.  In the event that a calibration check fails, an alarm is generated and the alarm log in the user interface is updated.

 

 

The requirement for periodic sensor cleaning can also be a labor-intensive activity.  The highlighted section below describes the requirement in the Guidance Document:

 

 

 

 

 

This requires you to periodically remove the probe and clean it, although it can be difficult to determine how often this cleaning must occur.  Excessive dust build-up can either cause alarm conditions to be suppressed or it can also cause false alarms.

 

The PCME DT990 probe has a patented electronic procedure called a contamination check.  By sensing the difference between the current from the measuring probe and a check probe, the sensor generates a “percent contamination” result that actually reflects how dust build-up is affecting the measurement.  The contamination result is available at the operator interface at all times.  When the contamination result exceeds 25% an alarm is generated and logged.  This alarm is the operator’s cue to initiate the cleaning procedure.

 

MACT standards also require/allow you to set the alarm point of the leak detection system at least once per year.  The alarm point is based on the typical response of the detector during normal operation of the baghouse.  The alarm point also needs to be adjusted whenever the characteristics of the particulate change.  If the size, composition, or charge of the particulate changes; the response of the leak detector will change as well.  B3 Systems can conduct the initial installation and setup of the leak detector system (see Service Plan).  We also offer a yearly service contract that includes the yearly setup.  Because of the digital communication properties of the PCME network, setup and diagnostics can be conducted remotely using a modem or Ethernet connection.

 

 

 

Our team of MACT compliance experts are ready to answer your questions about how to implement the regulations at your facility.  We can also help with finding the right sensor for your particular application.