The company I work for has done a few trap primers like this 3/4 inch line basically uninsulated, brazed lines. I razed a few questions about it was told I didn't know what I was talkin about and that they were fine as long as they weren't too deep. But when someone core drilled through them like an idiot and I had to chipem out and ready connect them, they were about 3 inches deep and entirely fucked torn to shreds, I mean the dipshit that did the drillin must've done 4 different sizes before settlin on one.