How to Choose the Right Fittings Selecting Your Fittings Basic Fitting Types
Pipe Thread Sizes
Certificates of Fittings Compliance
After you've decided on the right pump, chromatography system, or fermentation equipment, you'll want to make the right connections. The wrong fittings can cause leaks, unwanted flow restrictions, and costly downtime. The proper fittings let your equipment do the work that you intend it to do. That's why Masterflex offers such a large selection of fittings. Whether you're connecting microbore tubing or pipes, you'll find the right fitting for your application among the wide range of fitting types and sizes offered here.
- Consider the Tubing Used
Barbed fittings work best with flexible tubing such as silicone or PharMed®. Compression fittings work well with rigid tubing such as PTFE or polypropylene.
- Determine Material Compatibility
Fluids that are incompatible with fitting material may cause leakage or system damage. For highly corrosive fluids, PTFE fittings are best. See our Chemical Resistance Charts to check the material compatibility of your fluid.
- Check Temperature and Pressure Conditions
Make sure the fittings you choose are rated for your operating conditions. Most fittings are not capable of performing at their maximum temperature and maximum pressure ratings simultaneously.
slide into soft tubing. Tubing elasticity holds the tubing onto the fitting for low-pressure installations.
| Barbed |
are quick-disconnecting fittings to use with hose. Connect a female coupler to a male adapter and pull down the arms for a secure connection. Capable of withstanding high-pressure applications.
| Cam |
are a type of compression fitting designed for HPLC and other high-pressure applications. These fittings withstand pressures as high as 1000 psi.
| Chromatography |
have a nut that compresses rigid tubing against fitting body for high-pressure applications.
| Compression |
are designed to work with microtubing and luer-type syringes. Standard-sized connecting ends make luer fittings, stopcocks, and manifolds completely interchangeable for surefire installations.
| Luer |
are threaded in NPT (National Pipe Taper), UNF (Unified Fine Thread), or BSP (British Standard Pipe) sizes for permanent, high-pressure pipe connections.
| Pipe |
Quick Disconnect Fittings
allow you to make and break tubing connections without separating tubing from fitting. Available with barbed, pipe, compression, and John Guest® connections.
| Quick |
are designed for contamination-free tubing connections. Most of these autoclavable fittings meet FDA and USDA requirements and 3A Sanitary Standards.
| Sanitary |
Originally, pipes were specified with a standardized outside diameter (OD) and wall thickness so that the nominal pipe size would approximately equal the inside diameter (ID). Because this relationship between the OD, wall thickness, and nominal pipe size no longer holds true, NPT (National Pipe Taper) and UNF (Unified Fine Thread) inch scales are different from the standard English inch scale.
also offers BSP British Standard Pipe) fittings for connecting systems that use both NPT and BSP thread configurations. See the table below for a comparison of these two thread styles.
|Size ||Threads per inch |
|NPT ||BSP |
|1/8" ||27 ||28 |
|1/4" ||18 ||19 |
|3/8" ||18 ||19 |
|1/2" ||14 ||14 |
|3/4" ||14 ||14 |
Our customer service teams can provide a certificate of resin or elastomer compliance for many of our fittings, tubing, and gasket products. You can request this FREE documentation at the time of purchase by checking the "compliance" option for a specific item. Certificates list your company's PO number, order reference number, catalog number, formulation, compounding number, lot number (where applicable), and the regulations and agencies the fitting, tubing, or gasket complies with, including FDA, USP, USDA, National Formulary, NSF International, GMP, and 3A.
Look for the "certification icon" throughout these sections to easily identify when a certificate of fitting compliance is available. Shop products with Certificate of Compliance available.