Dust Pipe T's or Y's which is better

I'm in the middle of redoing my dust collection pipe. Moving from 7" tape / screws to a 8" Nordfab type of system in prep for my new DC arriving in the next month or so.

Gave the drawing of my shop to the pipe manufacturer have the following issue:

I have a main trunk moving down the middle of the shop with 2 branches. The branches have all of the machines. All of the pipe is 8" except the drops which are 8x6x8 Wye's to 6" & 5" gates.

The pipe manufacturer gave me 2 - "T" sections for the main branches. They are not Wye's like I was expecting, a hard T. I questioned them on the efficiency of the T vs the Wye and they said the T's are very efficient and will not know any difference. The air has to make a sharp 90deg turn to get to the main trunk vs a sloping curve with a Wye.

I'm skeptical... At this point I'd like other recommendations, should I send back the 8x8x8 T's and ask for 8x8x8 Wye's to allow a better slope into the main trunk going to the dust collector or just stick with the 90deg T sections.

I'd challenge the supplier to show the T is as efficient as a Y and/or contact Nordfab for their opinion (in their own design document they only show Y's for branches, although they do make Ts). I've always avoided sharp corners - not just for efficiency but also avoids any potential trap points

In all my reading and research before designing my dust collection system I don't ever remember a "T" recommended for dust collection.

Read what acknowledged authority Bill Pentz has to say, especially on Ducting / Ducting Components / Fittings / Wyes:
http://billpentz.com/woodworking/cyc...g.cfm#fittings

I'd send them back and insist on wyes. Show them the diagram if needed.
Attachment 365943

The entire Pentz site is often recommended for a little light reading on the why and how of dust collection.

JKJ

That is what I thought. I was so surprised about getting a T and not Wye's for those connections. I'll return them and get the right ones.

Tees are an absolutely "no-no" for a dust collection system...

Adding a wye and an elbow to complete the 90 if needed is pricey in 8" nordfab. 6" is better but still hundreds of dollars per pair. You will need to plan the extra room for that pair as well. Also make sure you are getting the long radius 6" 90s as the sell a short radius as well.