The High Pressure Fittings used in Misting Systems are just one step above the normal pressure. They are typically not much more expensive than your off the shelf hardware store varity. But yet they can be a little harder to fined. Remember, these fitting are 1/4in, 3/8in, or at the most 1/2in in size.
Your choices depend on your operating pressure which depends on a lot of other factors. System capacity, Pump, Budget, number of nozzles needed, etc.
Fittings come in several different materials which equate to different pressure ratings. Plastic (Nylon) fittings, the 1/4in. variety, for high pressures will have a working pressure of 200 to 250 psi. These fittings are ideal for diaphragm pumps and some variety of nozzles.
Tube End with 10/24unc © Misting Solutions.com
When we move into higher pressures there are three different types of fittings for misting. Compression fittings, slip lock fittings, and quick connect. Each one of these can be made with different material. The two main materials are brass or stainless steel. Cast Brass can be questionable rating. Is it strong enough for the size of pipe you are useing. Smaller sizes are generally not a problem. Check to make sure. Machine brass part made out of a solid block of brass to give it the strength for the psi ratings needed.
Typical fittings at the hardware store are only rated for around 150 psi. Some 125 psi and some maybe 200 psi. Small plastic slip-lock fittings may only be rated for around 80 to 100 psi. PVC household fitting for water supplies will be rated for 125 to 150 psi. There typically are not many fittings at hardware store settings that are rated high enough for high pressure misting systems. Some smaller brass 1/4in and 3/8in fittings can operate at several hundred psi but never over 300 or 400 psi. You have got to check the rating.
Cast Brass Fittings - Nickel Plated Quick Connects
Below are 3/8in cast brass fittings designed for misting systems. They have a rating of 1000 psi working pressure.
Quick Connect Fittings for 3/8in Tube © Misting-Solutions.com
Cast Brass Union - Cut in Half for Display
Quick Connect fittings are a nice alternative to Stainless Steel Compression Fittings. As you can see there are a variety of tube Quick Connect Fittings that use a locking set screw. They are made of brass with a nickel plating. They are probably not deemed as reliable as Compression Fittings but they are quick to install.
Quick Connect Unions with Set Screws © Misting Solutions.com
Stainless Steel Fittings
Stainless Steel may be the best material to use with misting. However, it can be expensive, to expensive for most home owner applications. Material costs can be 3 to 5x that of brass slip-locks, quick connects, or plastic tubing.
Stainless Steel fittings are generally the product of choice for most industrial and commercial applications. There is a higher safety margin in the design pressure ratings. Also, a stronger resistance to damage of accidentally bumped, run into, or hit.
Slip-lock fittings for plastic or nylon tubing
There is wide varity of high pressure brass slip-lock fitting for nylon and plastic tubing. Many times they will have a nickel plated coating. The nickel plating give it a silver coloring and help prevent discoloration over time. This give it a good look after years of use. Slip-lock fittings are typically used on plastic or nylon type tubing. They are usually found in the 1/4" and 3/8" size ranges. You don't see 1/2" slip-lock fitting because of the difficulty of making 1/2" plastic or nylon tubing rated at 1000 psi. It can be made but the wall thickness gets so great that flexibility is reduced and the inside diameter is not much bigger than 3/8" tube.