Life Cycle of Grooved Couplings

The typical response by manufacturers is: "The life of the system"

Life-Cycles of various systems utilizing grooved couplings

HVACR Systems 10 - 35 Years
Fire Systems 15 - 25 Years Inspections every 5-6 years.
Data Centers - 10 - 15 Years
Cryogenic Systems 5 - 20 Years
NOTE: Inspections are recommended more frequently than the "Life of the System" identified above. In more critical applications, it may be as frequent as 5 years.

Why should you inspect grooved piping systems before the end of their life cycle?

Grooved coupling manufacturer's Life-Expectancy determinations are based on an engineered perfect installation. This simply is not the reality with field pipe fabrication with a wide quantity and quality of pipe fitting vendors. Here are 3 conditions that warrant inspections before the end of the Life-Cycle of a system.
Visit our Risk Mitigation Page for more details on these conditions.
Risk Mitigation
System Vibration Fatigue
C.U.I. Corrosion Under Insulation
Installation Quality & Conditions

Calculated Failure Rate of Couplings

“Some forums depict grooved piping systems such as Victaulic as notorious leakers compared to welded systems, while others speak to their life-long reliability.”
“One site did relay an estimated failure rate for mechanical, rigid shaft clamp/compression type couplings of 14 failures per million hours. (Weibull shape parameter = 2, characteristic life = 9 years, replacement interval = 15 years).” source LINK: Eng-Tips.com /Victaulic Couplings in Data Center - HVAC/R engineering - Eng-Tips

This translates into 1 failure for every 71,429 hours ~ every 8.15 years.

Cases of Grooved Coupling failures in Water Piping Systems.

Link to Testimonial Page: Click Picture
C.U.I. CORROSION UNDER INSULATION: Failures of Grooved Piping Lead to Them Being Specified OUT of Chilled and Heated Water Applications (by U.S. Govt.)
The recent DRM (Design Requirements Manual) update has significantly changed piping requirements. NIH-DRM Exhibit 6.3
“Piping Designation, Material, Fittings and Joints”1 previously stated that grooved piping was approved for use in various mechanical applications, including chilled water, condenser water, and process cooling water.
The DRM revision, however, has REMOVED grooved piping and the associated joints as an acceptable option for these mechanical and HVAC applications (see updated DRM Revision 1.1, dated 8/22/2018).”
While the industry accepts the use of grooved piping for these applications, it’s impossible to inspect the joints to ensure ongoing integrity once piping is installed and fully insulated without removing and later re-installing the piping insulation

Over the past several years, the NIH Campus has experienced several high-profile failures of grooved piping joints on chilled water and heating water applications. These failures resulted in flooding, loss of building use, impact to research, and significant costs associated with remediation.

Nordblom Case Study: Motivating the Cox Over Coupling Clamp invention
  • Had taken over management of a complex of 3 buildings originally built in the very late 90’s/early 2000s With a mixture of customers, including a large customer that required 24/7 chilled water cooling that could not go down
  • 2 different bolts for Victaulic Grooved Couplings, in two different locations, snapped and caused losses water rushed out, and flooded areas were impacted. The insurance company was concerned this could be systematic and wanted the issue addressed to keep coverages in place. We did a facility-wide inspection and saw that other bolts were either over-torqued and/or were just not the proper bolt for the application. They urgently addressed the situation, or if more such failures, they might lose insurance.
  • The Dilemma
  • Taking down the system to do “dry service” would cost them millions in rental fees.
  • We could utilize roll-out coolers and shut-off valves and do a complete shut-down of non-vital systems for a few days, which would be very expensive and disruptive.
  • Unpredicted failures in certain locations (some labs had millions in equipment) could also be devastating.
Only a small handful (perhaps 10) of roughly ~1100 total couplings were not able to have their bolts replaced and properly tightened in this manner were reserved for future to handle in the least disruptive manner found several additional bolts that showed signs of cracking and likely would have let go over time they encountered plenty of corrosion that was far more than expected, especially under insulation

"We could have lost our underwriting and then have been exposed to the potential for millions in damages in losses depending on what got damaged"