UW1981,
I'm not surprised Bonney Forge couldn't provide information that might reduce their sales. Also, there is a liability issue. Reinforcement is required many times for reasons other than area replacement at a branch. Area replacement is straight forward. Other requirements for reinforcement are up to the design engineer.
In the petrochem industry that I'm familiar with, the break between butt-weld piping and socket-weld (or threaded) piping is generally at 2" NPS. 2" NPS & below is socket-weld and above 2" NPS is butt-weld. I've seen this break at 1 1/2" NPS but it's not that common. Assuming the break is at 2" NPS, then all of your piping and branches for run sizes 2" NPS and below would have socket-weld or threaded full or reducing tees.
When your run size is above 2" NPS, all of the branches 2" NPS and below would be sock-o-lets or thread-o-lets. For piping above 2" NPS, welding tees are used for size on size connections and reducing welding tees are common when the branch is one line size smaller than the run.
For the rest of the branches for run piping above 2" NPS, depending on your reinforcement requirements, you can have a stub-in, stub-in with re-pad or weld-o-let. The guideline here is usually economics or client preference. If you don't need reinforcement, go with a stub-in. You can always add reinforcement to a specific branch if required to reduce the SIF's.
Where reinforcement is required and based on economics, weld-o-lets are used up to 6", 8" or 10" branch sizes and re-pads are used for the larger braches. This is based on the total installed cost comparison between using weld-o-lets and re-pads considering material costs (weld-o-let vs. pad), the amount of welding required and labor. Naturally this changes year to year and location to location.
Some of our clients have preferred to use weld-o-lets all the way up to 20" NPS (that's a chunk of steel) and some clients have wanted all connections reinforced, whether required or not.
Back to your original question, my experience is that all branches 2" NPS and smaller are reinforced with an o-let of some kind.
I hope this helps. If you're looking for something in black and white, you're not going to find it. The guidelines I've given are general and based on my experience in my industry, of course there are exceptions.
Good luck,
NozzleTwister
Houston, Texas