tapered/NPT -vs- straight/BSP - is BSPP worth the cost?

[Harry in Ky]

Another vote for O ring ports. BSPP may be as effective, but much more expensive, with fewer options as far as fitting style and multi-sizing combinations available. O ring fittings can be found anywhere. For me, it's O ring port components and JIC lines and hoses. NPT is rarely an option except in cases where the component is only available that way.

 

[hayden]

I hate NPT. Very prone to leaking, and very difficult to fix when they do leak, especially if you have a bunch of stacked parts like you have planned. O-ring Boss (ORB), or o-ring face seal (ORFS), or JIC are my preferences. Also check DiscountHydraulicHose.com

 

[Tinhack]

Really, tapered threads are best used in low pressure assembled once situations.

Hogwash! All my shop 10,000 psi pumps and hoses use NPT fittings. If your NPT fitting is leaking, it was installed incorrectly. Any fitting will leak if you don't know how to use it.

 

[etpm]

Hogwash! All my shop 10,000 psi pumps and hoses use NPT fittings. If your NPT fitting is leaking, it was installed incorrectly. Any fitting will leak if you don't know how to use it.

Good for you. I'm glad your stuff doesn't leak. And I'm sure you regularly unmake and remake those NPT connections. Nevertheless it doesn't change the facts stated in my post. Because they are facts.
Eric

 

[Shenandoah MF1760]

One of the issues with NPT is the same with anything, cheap garbage from overseas.

I've seen people split low quality NPT fittings with loose threads in an attempt to get them to seal, despite pipe dope or tape even on systems below 150 psi.

I like BSPP, but it's usually only available at industrial suppliers and typically in stainless.

It all boils down to what's the application, how permanent is the installation, how much are you willing to spend, how long are you willing to wait on parts, and are the o-rings (if involved) compatible with the fluid?

If I was running pipe for natural gas, propane or a compressor I'd probably go cheap with black iron and NPT.

If I'm working on my tractor I'd go stainless and braided hoses with BSPP, the brewery I'd use stainless and tri-clover fittings.

 

[aa2tn]

Well I worked in an aerospace company's hydraulic maintenance department for 20 years and we used everything. Pressures up to 10K, temperatures up to 250F, and several different fluids. Most all, probably 90 percent of our leaks were fittings with O-rings. If money or availability is a problem mix in just enough O ring fittings to make it easy to repair when the time comes. One thing we always did with not fittings is to use both tape and dope, and stay off the first thread to avoid contamination issues.