A Contrarian View: Standards, Sensors, Squirrels, Unintended Consequences

By Heinz P. Bloch, P.E.

Several months ago, I happened to look at API-618. In the process, I noted that this venerable standard covering reciprocating compressors had grown from 34 pages to 39 (in 1974), to 111 pages (1986), to 166 pages (1995). There’s been at least one edition since—I don’t know how many pages it currently comprises. Standards and edicts will be with us for a while. Adhering to them will be expensive, as will not adhering. Take your pick. Consider the following example.

Some jurisdictions in Texas require certification (and fees) before a lawn-sprinkler servicing company can do business. In Harris County, where I spend much of the year, sprinkler systems must include rain sensors. If it rains, these systems either shut down or won’t start. If there’s no precipitation, the cycle timer calls for the sprinkler to run, and it will. Unfortunately, the sprinkler doesn’t know that it might start raining in, say, about an hour.

Even as rain threatens, my cycle-timed sprinkler system starts and dispenses water. If the sky opens up a little later, sprinkling earlier will have been a waste. When I’m home and listening to (and trusting) the weather report, I can save money and precious resources by deferring the sprinkler’s run to the following day. While no great harm is done up to that point, problems can arise later.

That’s what happened with a mature oak tree that once graced my front lawn. It provided ample shade and likely saved in excess of $200 on my yearly air-conditioning bill. Last December, the tree suddenly lost its leaves: It had died from lack of water, and needed to be removed by a commercial landscaper.

With the cooperation of the previous homeowner, it was determined that a single pair of low-voltage wires running from the rain sensor to the sprinkler system’s control module had caught the attention of a neighborhood squirrel. One of the wires was chewed through—probably in mid-2014.

That squirrel had caused a chain of events costing close to $2,000 for tree removal and a tiny replacement tree. The $2,000 does not include the likely incremental power that will be consumed over the next decade. That’s what it will take until my small and unimpressive replacement tree provides a measure of shade.

The above experiences led to several observations, some of them astute and others, perhaps, not so astute.

• Not all standards improve with successive editions.
• Prevailing sprinkler legislation makes little sense if it starts raining right after a sprinkler system completes its running cycle.
• A small animal can cost you more than prevailing legislation will have saved you in the past or will save you in the future.
• The unintended consequences of installing an instrument can cause grief and/or waste energy. It may even do harm to the very environment it was expected to protect.
• I should have used a checklist. Checklists are useful for preventive maintenance in plant environments and around the house.
• I should have acted on my distrust of squirrels or acquired a taste for them. The process operators at my former employer’s OXY-Unit in Baton Rouge, LA, did just that. In mid-1971, they invited me to share lunch, but suggested I not ask what was in the stew. They had a way of taking care of pesky squirrels, raccoons, and opossums.
• Rain-sensor wiring at 2,300 V would keep squirrels off my property.

If you wonder about my agenda, I don’t have one. I trust you will draw your own conclusions. MT

heinzpbloch@gmail.com