IIAR

BY KEM RUSSELL

When big things happen they really draw our attention, but in most cases it’s the little things we miss that can result in unexpected and sometimes undesirable results. We might breeze along taking account of larger items, not realizing or taking time to think that little details can make a big difference. As engineers, contractors, owners and operators, and educators we each have to pay attention to the little details to make the whole (the big thing) work correctly. Here are some examples of how little details can make a big difference . . .

A large freezing processing facility had been shut down for several weeks as new pieces of equipment were installed. Along with the new equipment, a much needed upgrade in the control assemblies for the new equipment was also done. One thing that was especially needed was new insulation.

In the past when I had visited this facility, all of the control valve assemblies for the freezing equipment had been extremely iced up. In almost all cases you could not operate a hand valve, or even find the hand valve under the ice. Any adjustment to control valves required ice removal before adjustments could be made. Newly assigned personnel to the refrigeration department were given the task of carefully removing the ice from the valve assemblies, which was a continual job since the freezing process did not shutdown.

With correctly applied new insulation and vapor barrier the control assemblies would be kept frost free. In addition the low pressure receiver (LPR) was also completely re-insulated. This included not only the vessel, but the ammonia pumps, float column, and associated piping.

The day I arrived at this facility just happened to be the day the system was started back up. At first all seemed to be going well, then one of the new operators noticed they were low on ammonia in their three (3) high pressure receivers. The Chief Engineer said “We can’t be low on ammonia. We had it all when we shut down and we haven’t had any leaks or releases. So, go find where it went!”

A clue to where the ammonia was – came when the single operating screw compressor used for the initial pull down started to unusually frost up. Fortunately, it was shutdown prior to any serious damage happening. Why was the ammonia flooding back?

At the LPR, an operator climbed up a ladder to check the operating floats. The make-up float appeared to be closed, which when closed would de-energize the LPR liquid make-up solenoid. The high level shutdown float appeared to not be closed indicating that liquid hadn’t reached that high.

As everyone stood by the LPR the discussion went something like, “It’s winter and cold outside. Maybe the liquid migrated up to one of the condensers?” It hadn’t. “Maybe some of the liquid feed valves on the new equipment are leaking.” This wasn’t it either.

The suggestion was made to verify the float switches on the LPR were working correctly. The head of the make-up float was removed and tipped back and forth. The liquid feed solenoid clicked ON and OFF with the float switch. That seemed to be working. Maybe the float ball in the float had failed. The entire make-up float was changed out, with no change in the result. An operator was on a ladder up next to the make-up float when the second float check was done. As everyone was standing around wondering what in the world was going on, the operator on the ladder pulled the head up off the float and dropped it back down. Then he noticed something, “Hey, how far down is the head supposed to go?” The answer was just a little bit further than it was going down, same thing was happening with the high level float.

When the float column was reinsulated, the insulators had installed the insulation around the float chamber just a little bit higher than previously installed. This additional insulation kept both floats from operating correctly. Now we all knew where the ammonia was. The LPR was very nearly completely full.

Just a little bit of extra insulation had made a big difference and could have resulted in a very expensive accident.

Here’s another example of a little detail that caused confusion.

I was working with the Chief Engineer at a facility that was also about to start-up. The Chief was going through the system using the P&ID’s to not only check things in the system (line sizing, valves, valve tags, etc.) but also to help understand what went where and how it worked.

In the machine room there was a float drainer assembly to remove any liquid that might condense in the main hot gas supply line feeding out the system. The Chief Engineer looked at that assembly and its piping, looked at the drawing and asked me, “I just cannot figure out how this works.”

I explained how the float worked. The Chief thanked me and said he understood how this worked, but still couldn’t match up what he was seeing with what was on the P&ID’s. I looked at the drawing for a few seconds and said “You see those two little lines connecting to the drainer. They are switched. The one on top should go in the bottom and the one on the bottom should go to the top.” The small detail on the drawing had been missed. Fortunately, the Chief Engineer picked up on the error, others may not have.

Lessons learned about little details also impact our personal lives. Here’s a personal experience.

My youngest daughter and I had planned a long multi-day hike. We had planned for this hike for months and carefully selected all of the gear and equipment we thought we would need. We considered not only the function of each item, but also its weight. The trail began in another State, and we flew, and then got transportation to the trail head from some very helpful people. We started out on a pretty warm day and over the next several hours finally made the 20 miles to our first destination.

I was really hungry, but first we had to set up our camp. After selecting a nice flat spot, we each set up our tents. Then I got water to heat and pour into our freezedried meals to re-hydrate and cook.

Since the first part of the trip was on a plane, there are certain items you cannot bring with you. A fuel canister is one of those. Fortunately, we were able to purchase two small fuel canisters after we landed so we were all set.

I got the small stove screwed onto the fuel canister, the water in the small pot, and had our two freeze dried dinners close by. Now I was ready to light the stove. I always carry two small lighters, one as a backup. However, since we flew I couldn’t take my small lighters on the plane, and I had planned to get those lighters when I bought the fuel. Unfortunately, I hadn’t. For want of a small flame, or even a spark, dinner wasn’t going to be cooked or eaten that night. Fortunately for us there was a small store about a mile up a road where I was able to buy four little lighters. Lack of just one detail – a small flame just about put a great hike off to a very hungry start.

Little details can result in misunderstanding, confusion, accident, or just an unpleasant condition. Paying attentions to those little details can make a big difference so you don’t have to learn a hard or unpleasant lesson later.