I’m sure they’re not happy and they’d much rather just weld a simple branch connection as shown in Fig.328.5.4D (1) and move on. Most fabricators would, but the powers to be didn’t spec that out as an option! I don’t think I’ve ever been in a shop where someone hasn’t asked me “do we have to weld this fitting all the way out?” Is the B31.3 going to tell you how much weld to apply? No it’s not, unless the design engineer wants to calculate each weld in accordance to para. 304.3.3! That’s a possibility but in my experience, not a probability.

So with that being said, do you have the correct fitting for the intended service (pressure/temperature)? I mention this because there are an array of both full size and reducing size Olet fittings that can be used depending on branch and run thickness and subsequently, the amount of weld will vary. If I remember correctly, there is also a PipeOlet (not manufactured by Bonney Forge) that many fabricators overlook or forget about that’s also an integrally reinforced fitting and very specific to the run/branch thickness. If possible to use and because of the PipeOlet’s reinforcement design, much of the weld size problem is eliminated while reinforcement requirements satisfied.

That said, Bonney Forge has a “Weldolet Installation Manual” that gives a description of applying the reinforcing beads (fill & cap) but of course, doesn’t provide any reference to a code/standard of construction.

They say as quoted:
“REINFORCING BEADS- Reinforcing welds should be made at the crotch bevel areas of the fitting to provide maximum weld at the crotch tapering to minimum at the skirt. Particular care should be taken to weld only up to the “weld line”(they reference sketch). This eliminates the unnecessary use of continuous passes and prevents the erroneous practice of welding up to the rib on the skirt portion of the fitting. A continuous cover bead should be added to fill the bevel and provide a smooth tapered weld.”

The crutch of understanding the problem is twofold-
1. The basic principles of an integrally reinforced fitting (adding mass {fitting & weld] replaces material removed {hole})
2. Why 0.7T of the branch thickness is used as the reinforcing fillet weld size as required on all B31.3 branch connections. (Reduces/breaks the stress riser condition of the branch connection)

My advice, fill the bevel out and add the reinforcing fillet as recommended by the fitting manufacturers.