CEMS Tubing Damage

CEMS Tubing Damage

At a multi-unit facility, it was observed that most of the certified emissions monitoring system sample tubing heating circuits indicated open continuity. The heating circuits are important to maintain transported sample temperature needed for CEMS accuracy (emissions compliance).

After a brief investigation it became clear that the installation was performed by construction personnel that did not understand the sensitive nature of the tubing assemblies.

Engineering properly cascaded the OEM requirements of not less than a 20.5 inch bend radius into the construction drawings.  The OEM information was also available to the Contractor staff.  However, the sample tubing was observed to be strained by being conformed to tight radius cable tray, pulled taught over edges of grating, and in some cases poorly tied with nylon ties that broke leaving the tubing to move with the wind.

All these visible defects were in addition to the probability that the equipment was mishandled during installation.  All of the sample lines at each CEMS installation have bend radius below 20.5 inches in violation of the OEM specifications, resulting in irreversible damage to the sample lines.  Nearly all the 15 assemblies had circuit failures and needed costly replacement.

Contractor Savings

Minimal to no cost savings by performing an unsupervised installation.

Repair Costs

Owner: Difficulty with CEMS certification and continued compliance. Contractor: $50,000/unit to replace.

Supporting Images: 

Templates Tells the Truth!

If the Sample tubing is bent to a tighter radius than the template it violates the manufactures mnimum radius guidlines and is subjected to damage.


Sample Tubing pulled tight around a corner of tray (two places in this photo).  Also shows routing of tray/cable inside a ladder cage which is prohibited.

Creativity is Important in Construction...

Someone recognized the tubing was pulled over a hard grating edge...  Problem appeared to be resolved with liberal use of zip ties to hold a softener (gloves) in place...  There are several quality problems with this installation.