What You Need to Know About the Injection of Valve Bonnets


On the 19th of November 2013, 3pm, a steam explosion occurred at the Antwerp Refinery, Belgium.  The accident involved the boiler feed water system (operating pressure 70 bar (1015 psi), operating temperature 280 °C (536°F)) of unit 72 (continuous catalytic reforming, CCR).  Two contractors were re-injecting sealant on a leak box on the bonnet‐to‐body flange of a 16 inch motorized valve, when suddenly the studs of the flange failed.  The bonnet was launched into the process area, and landed at a 25 m distance.” ¹  Both technicians lost their lives.

We all know that there are risks when injecting at high pressures and temperatures and we also know that the equipment being injected is leaking for various reasons. Was the flange tightened in a controlled manner?  Was the flange alignment within tolerance?  Were the correct fasteners used?  Was the correct gasket installed? Has the flange previously been injected? So on and so forth.

At Innovator the safety of our people is of paramount importance.  That is why we have developed a proactive approach when dealing with bonnets or blind flange leaks.  The table below is taken from Innovator’s “Leak Repair Field Report” which is filled out by the Lead Technician performing leak repair at client sites.  This report is filled out on every leak repair job.

Before injecting any bonnet or blind flange we ask our clients to inspect the studs to ensure the integrity is intact.  If this can’t be done, or if the studs fail inspection, we provide our clients with two options: (1) Remove and replace each stud one at a time, using load rated c‐clamps, (2) Take measurements to design and manufacture a strongback to be installed on the valve prior to injecting.

By taking these proactive safety measures we feel that we are providing the best solution for the wellbeing of our employees completing these repairs, as well as the employees and equipment on our client’s site.  This is why at Innovator we consider ourselves “Your Partner In Building A Leak Free Workplace.”

For more information please contact your local Innovator representative.

¹ Source – TOTAL Refining and Chemicals – HSE Alert 2013-35