Pipe, Tubing & Fittings

The right pipe fittings depend on more than diameter. The material flowing through the line, operating temperature, pressure, pipe or tube standard, and connection type all affect which component belongs in the system. A fitting that threads or presses into place may still be unsuitable for the service.

DK Hardware carries plumbing fittings, pipe, and tubing for water distribution, drain-waste-vent systems, gas and fuel lines, irrigation, fixture hookups, repairs, and industrial piping. Start with the application, choose an approved material, then verify the size and connection at both ends before ordering.

Pipe Fittings for Water, Gas, Drainage and Irrigation

System	Common Product Types	Details to Confirm	Shop Categories
Potable hot and cold water	Copper, PEX, CPVC, brass, stainless steel	Potable-water approval, temperature, pressure, pipe standard, and connection system	Copper Fittings, PEX Fittings, CPVC Fittings
Drain, waste and vent	PVC DWV, ABS DWV, traps, adapters, cleanouts, caps, and plugs	DWV rating, nominal size, hub or spigot end, and local code	DWV Fittings, ABS Fittings, PVC Fittings
Gas, fuel oil and steam	Black steel, malleable iron, approved press fittings, nipples, and unions	Listed service, pressure, temperature, thread standard, joining method, and code	Black Steel Nipples, Black Malleable Fittings, Press Fittings
Irrigation and service lines	PVC pipe, polyethylene pipe, insert fittings, barbed adapters, and clamps	Pipe material, inside or outside diameter, pressure rating, burial requirements, and clamp type	PVC Pipe, Poly Insert Fittings
Fixtures and appliance hookups	Compression fittings, flare fittings, push-to-connect fittings, tubing, and adapters	Tube outside diameter, end types, material compatibility, and appliance requirements	Compression Fittings, Flare Fittings, Push-to-Connect Fittings
Process and industrial piping	Stainless steel pipe fittings, nipples, tubing connectors, unions, and sanitary components	Material grade, pressure class, connection standard, media compatibility, and cleanability	Stainless Steel Fittings, Stainless Steel Pipe Nipples

Common materials do not make a product suitable for every system listed above. Use the pressure and temperature ratings, certifications, manufacturer instructions, and local plumbing or fuel-gas code that apply to the job.

Shop Plumbing Fittings, Pipe Parts and Tubing

Product Group	Available Categories
Steel pipe and fittings	Black Steel Nipples, Black Malleable Fittings, Galvanized Steel Nipples
Plastic pipe and fittings	PVC Fittings, PVC Pipe, CPVC Fittings, ABS Fittings, DWV Fittings
Copper, PEX and brass	Copper Fittings, PEX Fittings, PEX Pipe & Tubing, Brass Fittings
Mechanical and tool-based connections	Compression Fittings, Press Fittings, Push-to-Connect Fittings, Flare Fittings
Flexible connections and tubing	Hose Fittings, Flexible Fittings, Vinyl Tubing, Poly Insert Fittings
Testing and repair	Test Caps & Plugs, repair couplings, adapters, water hammer arrestors, and replacement fasteners

How to Choose a Pipe Connector Fitting?

A fitting can look right and still be wrong for the job. Before ordering, check:

Application and media: Water, gas, steam, compressed air, chemicals, drainage and irrigation may require different materials, seals and approvals.
Nominal size or tube OD: Pipe and tubing use different sizing systems, so the same stated size does not always mean the same outside diameter.
Schedule or wall thickness: Schedule affects wall thickness and inside diameter, while pressure capacity varies with material, size and temperature.
Connection at each end: Confirm whether each end is male or female thread, socket, spigot, compression, barb, flare, press, push-to-connect or another type.
Pressure and temperature ratings: Make sure both ratings cover the system’s maximum operating conditions, as higher temperatures can reduce allowable working pressure.
Material and joining system: Pipe, fittings, rings, sleeves, jaws, cement, sealants and tools must all be compatible with the same system.
Certifications and code requirements: Potable water, gas, fire protection, sanitary and industrial installations may require specific listings or approvals.
Package quantity: Check whether fittings, sleeves, rings and nipples are sold individually, in packs or by the case.

When replacing an existing fitting, match the connection standard and dimensions, not just the size printed on the old part.

Pipe Size, Tubing Size and Pipe Nipple Measurements

Pipe is commonly identified by a nominal pipe size rather than its measured outside diameter. Tubing is often selected by outside diameter, although copper tube size and PEX plumbing systems also use nominal sizing conventions. Check the product specifications instead of matching parts only by the number printed on the package.

For threaded pipe fittings, verify the thread standard and gender on both ends. NPT is common in the United States, but NPS and other thread standards also exist. A fitting with the right nominal size will not seal correctly if its thread type does not match.

Pipe nipples are usually listed by nominal pipe size and end-to-end length. A close nipple is typically threaded across nearly its entire body, leaving little or no unthreaded section. Check the drawing or listed dimensions when clearance is limited.

PVC Fittings, PVC Connectors, CPVC and ABS

PVC, CPVC, and ABS are separate piping systems with different applications and joining requirements.

PVC fittings are available for pressure piping, irrigation, pool and spa systems, and DWV work. Select the fitting by its stated application, schedule, connection, and pressure rating.
CPVC fittings are commonly used in compatible hot and cold water systems. Match CTS or IPS dimensions as listed and use cement approved for the specific CPVC system.
ABS fittings are commonly used in drain, waste, and vent systems. Select products specifically marked for DWV service.

Do not substitute one plastic fitting for another because the nominal size or color looks similar. Solvent-weld systems require compatible pipe, fittings, primer when required, and cement. Follow the stated preparation and cure times before testing or placing the line into service. For threaded plastic connections, use only a sealant approved by the pipe and fitting manufacturer.

Copper Pipe Fittings and PEX Connection Methods

Copper and PEX can each support more than one joining method. Choose the method that matches the pipe or tubing, fitting series, approved tool, and installation requirements.

Connection Method	Common Components	Check Before Buying
Soldered copper	Copper fittings, flux, solder, and heat source	Tube size, fitting cup size, solder type, and jobsite fire precautions
Copper press	Press fittings and matched press jaws	Fitting profile, jaw size, tube preparation, service approval, and tool compatibility
PEX crimp or clamp	PEX fittings, rings or clamps, and crimping or clamping tool	PEX type, fitting standard, ring or clamp size, and gauge requirements
PEX expansion	Expansion fittings, sleeves or rings, and expansion tool	Tubing approval, fitting series, sleeve size, and tool head
Push-to-connect	Compatible fitting and prepared pipe or tubing	Approved pipe materials, insertion depth, tube support requirements, and service rating

PEX-A, PEX-B, and PEX-C describe how the tubing is manufactured. They do not make every PEX fitting or connection method interchangeable. Follow the tubing and fitting manufacturer's compatibility information.

Copper does not always require soldering. Depending on the application and product approval, copper tubes may use soldered, press, compression, or push-to-connect fittings.

Black and Galvanized Pipe Fittings vs Stainless Tubing Fittings

Many threaded black steel, galvanized steel, brass, and stainless steel products use NPT connections, but a matching thread does not confirm that two materials belong in the same piping system.

Black steel and malleable iron fittings are commonly specified for certain gas, fuel oil, steam, and compressed-air systems. Confirm the product's listed service and the code governing the installation.
Galvanized steel fittings and nipples use a zinc coating for added corrosion resistance. Confirm whether the material is permitted for the specific water, air, sprinkler, or utility application.
Stainless steel pipe fittings are available in different grades, pressure classes, and connection styles. Check whether the job calls for 304, 316, threaded, welded, press, or sanitary components.

When changing from one metal to another, review the approved transition method and the possibility of galvanic corrosion. A listed adapter or transition fitting may be required.

Pipe Fittings and Tubing Fittings FAQs

How do I choose the right pipe fitting?

Identify the service, pipe or tubing material, size standard, schedule or wall thickness, pressure, temperature, and connection at each end. Then confirm that the fitting is listed for the application and accepted by the code governing the project.

Can different pipe materials be connected?

Yes, when a compatible and approved transition fitting is used. The adapter must match both sizing systems and connection types. Metal combinations may also require corrosion control.

Is PEX or copper better for a water line?

Both can work in approved water-distribution systems. PEX is flexible and supports several mechanical connection methods. Copper is rigid and can use soldered, press, compression, or push-to-connect fittings. The choice depends on code, water conditions, installation method, access, and the existing system.

Can compression fittings be used on copper tubing?

Compression fittings can be used with compatible copper tubing when the fitting is approved for the application. Match the tubing outside diameter and follow the manufacturer's tightening instructions. Do not assume a compression fitting is suitable for concealed or inaccessible locations unless its listing and local code allow it.

What does pipe schedule mean?

Schedule is a wall-thickness series used for many types of pipe. A higher schedule generally has a thicker wall for the same nominal size, but schedule alone does not determine working pressure. Material, diameter, temperature, and product rating also matter.

Shop Pipe Fittings, Tubing Fittings and Pipe Parts at DK Hardware

Browse DK Hardware for new installations, maintenance, and repair work. Compare material, size, schedule, end connections, pressure and temperature ratings, and package quantity before ordering.

Contractors, maintenance teams, and project buyers can request volume pricing for larger material lists. For help matching a replacement, contact our 24/7 support with the manufacturer number, pipe or tube size, material, connection details, and photos of the existing part. Get all plumbing related supplies on DK Hardware.

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