Difference between Fittings and Adapters
Many people who work with plumbing and hydraulic systems use the terms adapters and fittings interchangeably. However, these two implements are different hydraulic accessories and are used for completely different purposes.
Hydraulic Fittings
A fitting is a piece that is used to connect hoses and tubes to one another in a safe and secure manner. By using fittings, hydraulic fluid is allowed to flow through tubing without leaking or fluctuating in pressure. Fittings are normally installed into the major components of a plumbing or hydraulic system. This includes the work port of pumps, valves, cylinders, and motors.
In short, fittings are used to facilitate a secure connection between various hoses and tubes that connect to the major components of a plumbing or hydraulic system. Moreover, various types of fittings can be used to create split flow, change the direction of the hydraulic flow, or change the elevation of tubing lines.
Hydraulic Adapters
While adapters can sometimes be used as fittings, their inherent function is entirely different. These small implements help connect at least two different-sized threads to one another. In other words, hydraulic adapters allow us to connect two different components that would normally be mutually incompatible.
There are some cases in which an adapter could also be a fitting, such as a case where a female ORB cylinder is to be attached to the end of a JIC hose. Here, the appropriate adaptor fitting is ORB male by JIC male. Moreover, ORB adapters are usually also fittings.
Most adapters, however, are not fittings and serve an entirely different function in plumbing and hydraulic systems. Adapters are used to allow interchange between differing component standards and different component sizes. If, for example, you are to connect a metric hose end to a BSPP fitting, you will need to use an adapter to do so.
Proprietary Fit
When making sense of hydraulic hose implements and how to put them together, it is important to understand proprietary fit. The construction of hydraulic hose systems and implements is determined by a large variety of national and international standards that dictate specifications for sizes and dimensions.
The standard that is most widely used in the United States is dictated by SAE standards. However, different manufacturers, especially those in other countries, will likely be following other standards like ISO.
Whether you are making use of a fitting or an adapter, it is essential that you find the perfect fit to prevent leakages and subsequent damage to your hydraulic or plumbing system. Accordingly, the best fit is a proprietary fit, and this is the case whether you want to match the hose to an application or properly match the threads of fittings and adapters.
Summary
Fittings are implements used to connect hoses and tubes to major components in a hydraulic system. Conversely, adapters are used to allow connections between hydraulic components of different sizes and types. To ensure proper and safe use of either of these two implements, it is important to always look for a proprietary fit.
Frequently Asked Questions
What is the difference between NPT and BSP threads?
NPT (National Pipe Taper) and BSP (British Standard Pipe) are different thread standards used in industrial piping systems.
NPT threads have a 60-degree thread angle and are typically tapered. BSP threads have a 55-degree thread angle and are available in tapered (BSPT) and parallel (BSPP) configurations.
These differences affect thread engagement, sealing methods, and compatibility. Titan Fittings recommends identifying the correct standard before installing or replacing threaded components.
Can NPT and BSP fittings be connected together?
NPT and BSP fittings generally should not be connected directly because their thread angles, pitches, and profiles differ.
Although some sizes may appear similar and partially engage, mixing incompatible threads can result in leaks, damaged fittings, or connection failure.
Titan Fittings recommends using an appropriately rated NPT-to-BSP adapter when transitioning between thread standards.
How can you identify NPT versus BSP threads?
NPT and BSP threads can be identified by measuring thread diameter and pitch, checking whether the threads are tapered or parallel, and comparing their dimensions against recognized thread standards.
NPT threads use a 60-degree thread profile, while BSP threads use a 55-degree profile.
A thread pitch gauge, caliper, and reference chart are the most practical tools for identification. Because some thread sizes are very similar, Titan Fittings recommends verifying multiple dimensions rather than relying on appearance alone.
What is the difference between BSPT and BSPP threads?
BSPT (British Standard Pipe Taper) threads are tapered and typically use thread engagement with an appropriate sealant to create a pressure-tight connection.
BSPP (British Standard Pipe Parallel) threads have a constant diameter and generally rely on a sealing washer, O-ring, bonded seal, or another designed sealing surface.
Titan Fittings recommends confirming both the thread type and intended sealing method when choosing BSP fittings.
Do NPT and BSP threads require different sealing methods?
Yes. NPT threads commonly use a compatible thread sealant to fill the small gaps between engaged threads.
BSPT connections may also require thread sealant, while BSPP connections typically seal through a washer, O-ring, or dedicated sealing surface rather than the threads themselves.
Titan Fittings recommends using the sealing method specified for the connection and fluid service. Thread sealant should not be applied indiscriminately to every fitting type.
How can I tell whether a pipe fitting is NPT or BSP?
Start by measuring the fitting's thread diameter with a caliper and checking the thread pitch with a gauge. Next, determine whether the thread is tapered or parallel.
Compare these measurements against NPT and BSP thread charts to identify the correct standard. A visual inspection alone is not reliable because some sizes look nearly identical.
Titan Fittings offers thread identification resources to help customers verify compatibility before ordering replacement components.
How do I measure male and female pipe threads?
For male pipe threads, use a caliper to measure the outside thread diameter. For female pipe threads, measure the internal thread diameter at an accessible reference point.
Next, determine the threads per inch (TPI) or pitch using a thread gauge. For tapered threads, measurement location matters because the diameter changes along the thread.
Titan Fittings recommends comparing the measurements with an appropriate thread standard chart rather than assuming the measured diameter equals the nominal fitting size.
What is the difference between nominal pipe size and actual diameter?
Nominal Pipe Size (NPS) is a standardized designation used to identify pipe sizes. It does not always equal the actual inside or outside diameter.
For example, a nominal 1-inch pipe has a standardized outside diameter of 1.315 inches. Its inside diameter varies with wall thickness and pipe schedule.
Titan Fittings recommends checking nominal size, actual dimensions, and pipe schedule when choosing fittings, reducers, or adapters.
How do I determine the correct replacement pipe fitting?
To identify a replacement fitting, verify the existing fitting's connection type, thread standard, nominal size, material, and pressure rating.
Also check the system's operating temperature, fluid compatibility, and sealing requirements.
Titan Fittings recommends matching the complete fitting specification rather than relying on physical appearance or approximate thread engagement. This helps reduce leakage, installation problems, and premature component failure.
What tools are needed to measure pipe fittings accurately?
Common measurement tools include a digital or vernier caliper, thread pitch gauge, ruler, and pipe-thread identification chart.
For more demanding inspections, specialized thread gauges and calibrated measuring equipment may be necessary.
Titan Fittings recommends recording thread diameter, pitch, thread type, and nominal size before ordering replacement fittings.
More questions: Pipe Thread Identification, Sizing & Standards