Another "Kelvin Kline" designer welding symbol. "If you can't find a real one that works for you, make up your own welding symbol."
I've seen symbols similar to the one you showed, but in my case the icon you showed in the tail was position to the right of the weld symbol where the length should be listed.
I've always said, the dumber the contractor, the better my bank account. The same goes for lazy detailers, because the mistakes will be corrected and the guilty will pay. I had one project where the designer was back charged $180,000 for incorrect welding symbols. Everytime the welders stopped welding because they didn't understand the "nonstandard" welding symbol, their time and the staff's time was charged against the designer. There were some real beauties on that project.
Best regards - Al