NPT, JIC, ORB Or BSPP? A Practical Guide To Identifying Hydraulic Fittings
If you work on hydraulic equipment in Canada, you know the pain of a mystery fitting that will not seal. This guide gives you fast, reliable field checks to identify NPT, JIC, ORB, and BSPP, plus what each standard looks like,how it seals, and where you will commonly find it. You will also get practical tips to stop leaks, choose the right sealant, and avoid rework on your next service window.
Start here: tapered vs straight, then sealing style
Grab a good light and a thread gauge. Your first decision is simple:
- Tapered thread: threads get tighter as you screw in. Likely NPT or NPTF.
- Straight thread: constant diameter. Could be JIC, ORB, or BSPP.
Next, identify how it seals:
- Metal flare seal: look for a cone seat on the fitting nose.
- O-ring seal: look for an O-ring at the face or in the port.
- Thread interference: tapered threads that require sealant.
From here, the rest is fast.
NPT and NPTF, explained and identified
NPT is National Pipe Taper. The thread is tapered and seals at the threads with sealant. NPTF is Dryseal pipe thread, often stamped as NPTF. The F stands for Fuel or Dryseal depending on the source, but in practice it means a tighter form that can seal without compound in ideal conditions. In the field, always use a compatible liquid thread sealant on NPT and NPTF for hydraulics. Loctite 567 is a common choice in shops, and it reduces galling and rework.
How to confirm NPT:
- Taper: measure OD at first and third thread, the OD decreases.
- No cone seat: the nose is flat or slightly chamfered.
- Thread pitch: use a thread gauge, common sizes are coarse per pipe standards.
What is the difference between NPT and JIC hydraulic fittings? NPT is a tapered pipe thread that seals on the threads, while JIC uses a straight thread with a 37 degree flare that seals metal to metal at the cone, not at the thread. You can adapt between them with the right pipe adapters, but do not try to mate them directly.
Should you put Teflon tape on hydraulic fittings? Use liquid thread sealant on NPT or NPTF in hydraulic systems. Tape can shred, migrate, and block valve orifices. If you must use tape in a pinch, start one to two threads back and apply minimal wraps, but paste is the better practice
JIC: the 37 degree flare you see everywhere
JIC stands for Joint Industry Council. It is a straight thread male with a 37 degree cone and a female with a matching 37 degree seat. The seal is metal to metal at the cone.
How to confirm JIC:
- Look for the cone: 37 degree on the male nose, matching female seat.
- Use a seat gauge: a 37 degree gauge fits flush on JIC, not on 45 degree.
- Thread is straight: no taper, threads do not do the sealing.
- Do not confuse with 45 degree SAE flare from automotive or low pressure refrigeration. A 45 degree cone gauge will rock on a 37 degree seat.
Field note: If a JIC flare weeps, inspect for scratches and use a JIC flare seal ring if allowed by your procedure. Tighten to spec, do not over-torque.
ORB: straight thread with an O-ring in the port
ORB means O-ring Boss. It uses a straight thread to draw the male fitting against an O-ring at the port face. The seal is the O-ring, not the thread.
How to confirm ORB:
- Look into the female port: you will see a machined counterbore with an O-ring.
- Male has a straight thread with a hex and a flat under the hex to compress the O-ring.
- No cone seat on the male nose.
Quick check vs JIC: JIC has a 37 degree nose that seals on the flare; ORB has no cone and seals on the O-ring at the face of the port. If you are bridging these, look for orb x jic adapters designed for that transition.
BSPP: the common international parallel thread
BSPP is British Standard Pipe Parallel. It uses a straight parallel thread. It does not seal on the thread. It seals with a bonded washer, an O-ring under the hex, or a captive seal at the face.
How to confirm BSPP:
- Straight thread, no taper.
- Often a flat or 30 degree seat inside the female. Many field connections use a bonded sealing washer under the male hex.
- Threads per inch differ from NPT. Use a pitch gauge and check nominal size by measuring the OD, then reference a BSP size chart. Do not size it like pipe; for example, a 1/2 in BSPP male measures around 0.825 in OD.
- Is BSPP the same as NPT? No. Thread angle and pitch differ, and BSPP is parallel. Do not cross them.
Do BSPP threads need sealant? Use a bonded washer or face seal. Do not rely on thread sealant to make a BSPP joint seal. You can add a small amount of hydraulic-compatible non-hardening sealant on threads for lubrication, but the primary seal is at the face.
How to identify BSPP fitting sizes: measure the male OD with calipers, count threads per inch with a gauge, and match to a BSPP chart. Confirm the sealing method, usually a bonded washer.
Side-by-side field checks you can do in minutes
- Thread pitch gauges: confirm pitch first. If the pitch does not match any NPT table and the OD is constant, suspect BSPP or a metric parallel.
- Cone angle check: use a combined 37 degree and 45 degree gauge. JIC is 37 degree. SAE flare is 45 degree. If neither sits, look for ORB or BSPP.
- Taper check: run a nut or measure OD across threads. Taper indicates NPT or NPTF.
- Seal location: O-ring in the port equals ORB. Bonded washer at the face equals BSPP. Metal to metal cone equals JIC. Thread-only seal equals NPT or NPTF.
Where you will see these in Canada
- NPT and NPTF: legacy machinery, manifolds, and general industrial piping across Canada.
- JIC: very common on mobile equipment, cylinders, and hose assemblies.
- ORB: widely used in pumps, valves, and aluminum or steel manifolds where an O-ring boss port is standard.
- BSPP: frequent on imported equipment, marine and forestry gear, and UK or EU sourced components.
Leak prevention and rework reduction
- Clean and inspect: dirt on a cone or O-ring face will weep under pressure.
- Replace O-rings: match material to the fluid and temperature. Lightly oil before assembly.
- Use the right sealant: liquid thread sealant on NPT or NPTF; do not rely on tape.
- Do not mix standards: never try to mate NPT to BSPP or JIC without an adapter.
- Torque correctly: follow manufacturer torque charts. Over-torque can crack flares and flatten O-rings.
- Support hoses and reduce vibration: add clamps and guards. Protect high movement loops with proper routing
If you need quick tests during a shutdown, a small hand pump and a temporary gauge help you confirm a suspect joint before you button up. A tidy bench test can save an hour on a cold restart.
Quick answers to common questions
- How to determine hydraulic fitting type? Check taper vs straight, locate the seal (threads, cone, O-ring, or washer), then measure pitch and angles with gauges.
- How do you tell what hydraulic fitting you have? Use cone gauges for 37 degree vs 45 degree, check for an O-ring in the port for ORB, and use thread pitch gauges plus OD measurements to separate NPT from BSPP.
- What does JIC stand for in hydraulic fittings? Joint Industry Council.
- What does the F stand for in NPTF? Dryseal or Fuel in older texts; in practice it indicates the Dryseal form. Treat it like NPT for assembly and use paste sealant in hydraulics.
- How to keep hydraulic fittings from leaking? Match standards correctly, clean and inspect surfaces, use the right sealant or washer, torque to spec, and support hoses to limit vibration.
Need adapters or replacements fast?
If you confirm you have mixed standards on the same machine, use proper hydraulic adapters to bridge them safely. When you are ready to order, you can browse hydraulic fittings and adapters by family. For example:
- jic fitting
- npt fitting
- bspp fittings
If you are connecting different thread families, see hydraulic adapters.
Summary
Correctly identifying NPT, JIC, ORB, and BSPP comes down to three checks: tapered or straight threads, where the seal lives, and the cone or face geometry. NPT and NPTF are tapered and seal at the threads with paste. JIC is a straight thread that seals on a 37 degree flare. ORB is straight thread with an O-ring in the port. BSPP is parallel and seals with a bonded washer or face seal. Use thread pitch gauges, a 37 degree and 45 degree cone gauge, and calipers for size confirmation. Avoid tape on hydraulic systems, use liquid sealant on NPT, replace worn O-rings, torque to spec, and support hoses to cut vibration and leaks.
Island Hydrostatics stocks fittings and adapters for Canadian conditions, with Canada-wide shipping and FREE shipping on orders over $99. Need help identifying a fitting? Bring a sample or contact our team, and we will match it and recommend the right adapter so your next startup runs clean and dry.
