ChipFuller:
Industry practice depends on the plant, the management philosophy, personnel needs/demands/unions, operating requirements, and a lot of other factors - just as in your plant operations. The present situation is that EPA and OSHA have no standards, rules, guidelines, or regulations on Ammonia connections or leak monitoring limits (except where it concerns spills and fugitive emissions) to my knowledge. There are literally hundreds of thousands of piped, process connections existing in the US alone - and nothing is done to monitor, inspect or regulate the screwed, flanged or hosed connections that are in storage tank areas, overhead pipe racks, on sleepers, inside process buildings, with or without expansion facilities, etc. In fact, I personally know that protection against liquid ammonia expansion betweeen two block valves is strictly up the owner and his PSM routine within the plant. There are no laws to "protect" you from spilling liquid NH3 or hurting someone - the involved plants must take a pro-active role in seeing to it that the operation is safe. Only AFTER an incident is the government able to step in - not BEFORE. This is unfortunate and it leaves the employees and personnel with the decision of plant/labor management.
I believe there is concern for the multiple times the liquid NH3 connections have to be made, and I personally agree that there is possibility for fugitive emissions or leakage. A monitoring system is a step in the right direction, but operability has to be respected and maintained; otherwise, a more serious accident can take place. Your safety department and your operators should be involved and allowed to work this problem out in concert with a total safety concern. In this specific example, I can attest to the fact that it should be very simple to detect fugitive NH3 emissions (if that is what you're after). A simple, metal shroud around the immediate area where the connections are should be ample to allow detection and also leave safe and ample room for operations and access. It is fortuitous that NH3 has such strong and pungent properties that a "sniffer" can easily pick up the ppms. This helps in not having to totally enclose the area and simply getting by with a shroud. I believe this will work and I would go with this first.
Art Montemayor
Spring, TX
