Mental Reprogramming

I gave a lecture today in rigging class I have done several time before. It is the introductory lecture to the "engineering" section of the course. The semester starts with a review of common systems and then transitions into the workings and selection parameters for the components of those systems - this is the section I started today.

Traditionally this class has centered around some terms: ultimate load, safe working load, proof load, safety factor, minimum failure load, design factor, working load limit. We talk about "rated" and "unrated" and we talk about "malleable" and "drop forged" and how these terms effect component selection. Then usually I ask then which of the terms above appear to go together, and then once we have them grouped we look at the relationship of one group to another, how to relate minimum failure load to working load limit, what is design factor, and how does proof load fit into all of this.

After all of that we talk about entertainment industry traditionally applied safety factors, what to apply in what kind of situation. Finally I talk to them about what it means to derate your safety factor, and what you need to do in terms of inspection, training, retirement, and engineering to protect yourself and the performers under those derated circumstances.

At least, that's what I used to do. Today was very different. Today I spent most of the time hearing myself in my head doing a mantra reminding myself: "Don't say safety factor! Don't say safety factor! Don't say safety factor!"

Safety Factor - No, Design Factor - Yes. (Bread good, fire bad...)

One of the most significant things to my experience as a Subject Matter Expert on the ETCP Rigging Certification was a sort of circling the wagons on technical terms. Actually this has been one of the biggest pluses of the experience going all the way back to the ESTA Certification Program Committee several years ago. I assume that it is a benefit of any high level professional interaction and I would advise everyone to seek out these kinds of gatherings and conversations.

Somewhere along the way in our deliberations we stumbled on the idea that you can't say safety factor anymore. My assumption is that this comes form industry and from litigation. The tone in the room was that by saying you employed a safety factor you were somehow warranting that you had made something safe, when really all you had done was to make something safer as there is always and will always be some element of risk in this kind of engineering. Our job is to design systems to best mitigate and minimize that risk - hence: design factor.

I guess saferty factor sounds stupid.

Today it was me that sounded stupid, hitching up every time I got to what has in the past been "safety factor" and having to remember to insert "design factor." I missed it about half the time. Finally I gave up and explained the issue to the class and then threw on top of it that SWL or safe working load was likely on its way out too. Time to remember to use working load limit.

It bothers me that we can't use the traditional language when the process we're describing isn't changing. If it really is for legal reasons, doesn't it seem appropriate that the process is what is important rather than the language. Derating the ultimate load is making the installation safer. Why should we not be able to call the coefficient applied to the ultimate to arrive at the safer number the safety factor?

And why can't they call flame proofing, flame proofing rather than application of flame retardant? Isn't it clear that eventually everything will burn? Does using different language somehow help that?

And weren't seatbelts originally safety belts?

I am going to miss safety factor.