SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

What kind of tubing? Drip tubing works differently.

First of all, the fitting you are pointing out looks like it is for a 1/2" thread to a 1" barb (not 1" thread to 1/2" barb).

Second, those fittings are designed for "standard" poly pipe. Drip irrigation tubing does not have "standard" dimensions. Each manufacturer makes theirs just a little different. So you have to either go with fittings made by the manufacturer to fit their tubing, or you use "universal" fittings like these made by rain-bird (http://www.sprinklerwarehouse.com/1-2-inch-Easy-Fit-Universal-Fittings-s/1057.htm the tubing fits inside the MDCFCOUP, MDCFEL, or MDCFTEE and the various adapters fit the other side, the idea is that you can take any size drip, run it through one of these three couplers, and place any one of the various adapters on the other side).

So I take it that what you are trying to do is go from a 1" female threaded valve to the 1/2" drip line, and you need a 90 elbow to boot. Your easiest solution that should still be reliable is to start with a 1"(fpt) x 1/2"(fpt) reducer bushing to take care of the 1" to 1/2" transition. If you are using DIG drip tubing, then use the DIG 1/2" fpt to barb elbow. If not, then you need to either get the universal fittings elbow (MDCFEL) and 1/2" fpt adapter (MDCF50MPT) (1/2" adapter goes in the 1"x1/2" bushing, the elbow goes on the adapter, the drip tubing goes in the other side of the elbow directly).

http://www.sprinklerwarehouse.com/PVC-Threaded-Reducing-Bushing-p/439-130.htm
http://www.sprinklerwarehouse.com/15-037-1-2-Barb-Fitting-p/15-037.htm

BTW, are you doing drip irrigation or regular irrigation? (You linked to drip tubing)

If you are doing drip irrigation, then you need a filter and pressure regulator installed between the valve and drip tubing (unless you have a filter and brass regulator BEFORE the valve).

If you are doing "regular" irrigation with drip tubing (which is what you linked to), then you are using the wrong poly pipe. Drip tubing is designed for low pressures and is not designed for direct burial (under mulch, yes, 10" under dirt, NO). You will notice that the tubing you linked to has a pressure rating of ONLY 60 psi. Irrigation poly should have a rating closer to about 150 psi.