Shared Learning - Safe Inspection before Repumping

What happened?

During a leak sealing operation on 19 November 2013 in Belgium on a 16” MOV (Motor Operated Valve) a steam explosion occurred resulting in the death of two employees. (Not Furmanite Employees)

What went wrong?

The incident occurred in Unit 72 (Continuous Catalytic Reforming) of the Antwerp Refinery. The line contained Boiler Feed Water operating at 70Bar/1,015 Psi and 280°C/536°F. While the workers were repumping the clamp/enclosure that was installed on the Bonnet of the valve, (the two workers were employed by an external contractor) the bonnet bolts suddenly ruptured. The valve bonnet was launched 25m/75ft into the production unit.

Background/Additional Information

The clamp/enclosure was installed in 2011. This was the 7^th (seventh) repump on the clamp/enclosure. Furmanite has a policy that after 3 {three} repump’s, engineering has to be made aware of this and the job has to be given extra attention to evaluate any possible factors that could be causing the requirement for it to be re pumped again and to consider if there are any extra safety factors that we must be made aware of. There is always a risk that when injecting at high pressures and temperatures, some of the older style compound ingredients or breakdown products in them may have previously been acting in a negative way on the internal parts of the system or the bolts. There is also a possibility that the actual medium (boiler feed water) has chemicals in it that could have been acting in a negative way on the valve parts or bolts as well.  

Investigation Results

            Immediate Causes

            Apart from the actual rupturing of the bonnet bolts, the exact cause of this is still unknown and under investigation.

 

How do we prevent it from happening again?

In all cases when attempting to seal high pressure and high temperature leaks, extreme caution must be used at all times.

No matter what the type of job is, review the area and the situation and ensure that if something were to happen, you are not in the path of destruction, and have two easily accessible routes of escape.

Before repumping anything, always check the structural integrity and the tightness of the bolts on the clamps/enclosures, restraints ect the best as you can. If there is any doubt as to their integrity, then do not proceed, consult engineering with your findings, and continue with a more complete review of the job.

After the third repump engineering must be made aware of the situation so that a complete review can be made to determine if there is a requirement to change the sealant being used, change the procedure being used and for any new safety precautions that must now be put in place.

 

What actions do I take?

 

·         All Furmanite Techs to be issued with this Safety Alert. (SDC Managers Globally)

·         All workshop supervisors / SDC Managers to ensure that leak sealing techs have access to a complete set of safety information on the compounds / substances that they use in their day-to-day operations and that their employees have been given suitable and sufficient information and instruction on their safe use. (SDC Managers Globally)

·         All Leak Sealing Procedures / risk assessments to be altered to reflect this safety alert. (Process Integrity Service Line Leadership)

·         All leak sealing class rooms training or CBT to include reference to the third repump rule and its requirements. (Global Engineering Manager)

·         Engineering Teams providing Chemchecks  and or engineering reviews are to make techs aware of the potential problems associated with working on Boiler Feedwater (with its chemical additives) and the effect it may have on the internal valve parts and associated bolting. (Engineering dept. manager)