HSE releases alert over hardness faults with clamp connectors
As per HSE inspectors, the failure of a 1” vector Techlok connector caused the release of gas in December 2014. Subsequent enquiries have revealed that the problem was not just limited to the 1” vector Techlok connector but was also prevalent in the 1.5” and 2” clamp connector segments as well.
Dutyholders have been advised to verify the fitness of any 2” or smaller Techlok or Destec G range clamp connectors supplied before 2010. This applies to those used in the field as well as those kept in stock for later use.
HSE inspectors have found out that hydrogen cracking was the root cause for their failure. As the metal clamps were made too hard, with values in excess of 48-50HRC on the Rockwell hardness scale, their susceptibility towards cracking increased because of the reduced ductility.
Before 2010, the safety checks, such as hardness checks, on these clamps were not made and there wasn’t enough quality controls on individual components to identify which component did not sufficiently receive the correct heat treatment and thus lacked ductility.
In order to ensure that the clamps are fit for use, the HSE has recommended their inspectors to ensure that the records of suppliers show that the material properties of the clamps are fully certified. In the absence of this HSE inspectors should carry out appropriate non-destructive tests to check for hardness.
These checks will not be required for segments which have been manufactured after 2010.
Dutyholders have been advised to verify the fitness of any 2” or smaller Techlok or Destec G range clamp connectors supplied before 2010. This applies to those used in the field as well as those kept in stock for later use.
HSE inspectors have found out that hydrogen cracking was the root cause for their failure. As the metal clamps were made too hard, with values in excess of 48-50HRC on the Rockwell hardness scale, their susceptibility towards cracking increased because of the reduced ductility.
Before 2010, the safety checks, such as hardness checks, on these clamps were not made and there wasn’t enough quality controls on individual components to identify which component did not sufficiently receive the correct heat treatment and thus lacked ductility.
In order to ensure that the clamps are fit for use, the HSE has recommended their inspectors to ensure that the records of suppliers show that the material properties of the clamps are fully certified. In the absence of this HSE inspectors should carry out appropriate non-destructive tests to check for hardness.
These checks will not be required for segments which have been manufactured after 2010.
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