IIAR

Blow out panels are sections of walls, louvers, hatches or doors that are designed to relieve pressure from an explosion. We are sometimes asked about the requirements for blow out panels for refrigeration engine rooms. To be clear, there is no code requirement for them for ammonia refrigeration systems. Section 911 of the International Fire Code (fire protection systems chapter) describes rules that are applicable when a hazardous material exceeds certain quantities. The code generally describes flammable gas as one of those materials that necessitate the use of blow out panels when specified quantities are exceeded. Of course, ammonia is a flammable gas under certain conditions. HOWEVER, chapter 35 of the IFC provides some specific exceptions to the definition of flammable gases. Most important to our industry is Exception #1: “Gases used as refrigerants in refrigeration systems (see section 606)”. Section 606 is the section on mechanical refrigeration with which most of us are very familiar, and there are no requirements for blowout panels within it. Some underwriters have been known to require blowout panels in engine rooms, and this has led some to believe that they are generally a requirement. Underwriters certainly have the discretion to require more stringent protections to buildings they insure, and they will typically provide design guidelines that will meet their requirements. However, there are many protections inherent in an ammonia refrigeration system design including generous ventilation requirements. With these protections and with proper maintenance and operation, the risk of an explosion is significantly minimized.

Ammonia inventory reporting is a necessity, and something that requires a bit of thought and preparation. We have received calls about what form to fill out if a facility has ordered 10,000 lbs. of replacement ammonia. First, there is the yearly inventory reporting requirement under the Emergency Planning and Community Right to Know Act (EPCRA) 312. This includes a Tier I or Tier II (if requested) report to the SERC (state emergency response commission), LEPC (Local Emergency Planning Committee) and the local fire department and must be done by July 1 annually. This report is on your entire inventory. Next, if a facility has received 10,000 lbs of refrigerant for a “re-charge” or “top-off”, it will be considered “otherwise used” under EPCRA 313. Additional conditions of this requirement are that facilities employ 10 or more people, and that the facility is classified as Standard Industrial (this is almost always the case). EPCRA 313 form “R” would be used to report this quantity (the amount added, but not the entire charge) by March 1 for the preceding year.

But when the reporting happens, and the ammonia orders are filled, an obvious question arises…What happened to the refrigerant that was in the system to begin with? This question might not come up immediately upon reporting, but a system manager would do well to figure it out ahead of any regulator that might take a look at the reports or invoices and ask that question. What I am suggesting is that when an annual report is filed, it is not a good idea to repeatedly report the same calculated figure of the inventory year after year and then later order more ammonia to “top off” the system. A savvy inspector would ask the question above, and wonder whether or not there was an unreported major release. So while it is likely an effort in futility to try to calculate exact losses, it is a good idea to make some reasonable estimate of refrigerant that was lost throughout the year and include that loss in annual reports. Typical sources of minor refrigerant loss are: purgers, compressor shaft seals, valve stem packing, oil draining operations, and minor repairs. An often-cited rule of thumb is 5%-10% loss annually of the total system charge, depending upon the age, size and condition of a system. It is worth keeping in mind that losses of 100 lbs. / 24 hours are to be reported to the EPA and the National Response Center. Losses beyond that figure need to be accounted for, whether they are caused by an accidental release, or intentional removal for maintenance or re-configuration.

IIAR will be introducing a newly revised and updated PSM/RMP guidance manual at the IIAR Annual Conference in Milwaukee. One new feature of the guideline is the minor leak reporting program, within the mechanical integrity section. This will help operators keep up with small leaks that do not warrant an immediate shut down, but can be addressed during planned maintenance. This is one means of helping to estimate annual losses so that when inventory reporting comes around, a more accurate accounting can be done and preparation can be made for the justification of adding more refrigerant to your system.