In October 2015 I wrote about justifying our Maximum Intended Inventories (MII) so that we balance business needs with risks associated with large quantities of highly hazardous chemicals on site. Now we have come full circle and now a facility is being asked to define their MII as it relates to their material and energy balances.
Background
The process involved is a closed-loop process that uses anhydrous ammonia as a refrigerant and the refrigerant process is a covered process that is attached to another covered process. The ammonia process was built in 2002, so the facility documented the material and energy balances for the refrigeration process. In doing so they listed the Refrigeration Tonnage for their major components, a very common method of meeting this requirement… but here’s the catch.
An agency is now taking issue with the process’s MII based on the process design. This means the agency is tying the MII to the material and energy balance. In other words, what I was trying to drive home last October, is that we NEED to justify our MII in some manner. In a closed loop process, we can calculate the amount of ammonia that is needed to meet the design of the process. We can have a little bit of a buffer for fugitive losses, but we are talking a couple thousands of pounds – not tens of thousands of pounds!
In this situation, ammonia refrigeration is NOT a major process for the facility so the training the personnel who are responsible for the process is NOT what we would see had they attended a “refrigeration school”. Since the personnel was not well versed in the intricacies of how refrigeration works, when they hit a snag in the process not providing the refrigeration as they had hoped for, the answer was… “more ammonia”.
Another contributing factor to this situation is the plant goes into a major shutdown/turnaround at least every five (5) years. In doing so the facility has the practice to put all of their HHC’s into the process’s single largest vessel in order to limit their risks when thousands of contractors are climbing all over the plant. The other reason is, all the other processes are using flammable liquids and gasses and by draining the process back to the tank farm(s), the facility can limit their HAZLOCs and thus they reduce their Flame Retardant Clothing (FRC) areas for the contractors. They applied this same design to their new ammonia process and installed a 30,000-gallon bullet (hugely oversized for a process contain 10,000 gallons or ~50,000 pounds).
So we have a team running a process that is not responding in the manner they expected and they came to the conclusion that more ammonia was the answer. And since there was plenty of room in the 30,000-gallon receiver they got more ammonia… and some more… and some more and when it was all said and done, by the time the agency showed up they had added 10,000 pounds, which exceeded their documented MII that was provided by the design and installation engineering firm and… was about 10,000 more than the process was designed for, based on the same engineering firms’ material and energy balance for the process. Turns out more ammonia was not the problem and that some fine tuning was needed to make the process more responsive.
Now we have an agency asking us to explain why the process has X pounds of an HHC when their MII and their material and energy balance says they only need Y. Would our argument be? Sometimes it is easy to loose sight of what the INTENT of OSHA’s PSM and EPA’s RMP standard are… REDUCTION of INVENTORIES of HHC/EHS’s. And just because our process is a “covered process” (i.e. we have already exceeded the threshold amount) this is NOT a license to store as much as we want. In a closed loop process such as an ammonia refrigeration process, these two bits of data MUST match up if we stand a chance at justifying our MII.
And finally, merely because a tank/vessel can hold X pounds/gallons safely does not mean we can put X pounds/gallons in it – it may be safe for the tank/vessel but that is NOT practicing PROCESS Safety!