Swagelok SS-810-1-8 Male Connector, 1/2 in. Tube x 1/2 in. MNPT

The Swagelok SS-810-1-8 is the standard way to land a 1/2 in. instrument or process tube on a tapered 1/2 in. male NPT port. One end is a two-ferrule Swagelok tube-fitting connection; the other is a machined 1/2 in. male NPT thread, so the fitting screws into a female pipe port on a valve, manifold, gauge adapter or vessel and then accepts the tubing run. It is cut from 316 stainless steel bar, and the Swagelok data page lists it as not bored through and without a flow restrictor.

Technical specifications

Reading the ordering number

Swagelok builds fitting numbers from blocks. In SS-810-1-8, SS is 316 stainless steel, 810 is the tube size code for 1/2 in. outside diameter, the first 1 is the fitting type (male connector) and the closing 8 is the pipe size in eighths of an inch, so 8 means 1/2 in. NPT. Compare SS-810-1-4, which keeps the 1/2 in. tube end but lands on a 1/4 in. pipe thread, or SS-810-2-8, the 90 degree version with the same threads. Catalog suffixes change the end: RT is ISO tapered thread, RS is ISO parallel with a straight shoulder, ST is an SAE/MS straight thread with O-ring and W is a weld end. Those are different part numbers and should not be assumed from this page.

Add CP to the number for individual bagging, or BQ for the cleaning-and-packaging level the catalog describes with silver-plated front ferrule and Krytox-treated nut, for example when oxygen or analytical service requires it.

Pressure, threads and sealing

A tube fitting is only as strong as its weakest end. The tube end is rated to the working pressure of the tubing you fit, which comes from the Swagelok Tubing Data catalog; the NPT end is rated from the pipe-thread table, where a 1/2 in. male 316 stainless connector is listed at 7700 psig (530 bar) at ambient temperature. The threads follow ASME B1.20.1. Tapered threads need a sealant, and the catalog points to SWAK anaerobic sealant or PTFE tape. Seat the thread, then make up the tube end separately; never turn the fitting body to tighten the nut.

Because the rating is ambient, derate for temperature using the tubing and material data rather than reading 7700 psig as a service limit. The nominal opening E is 0.41 in., which is the smallest passage in the fitting; where flow area matters, compare it with the tube bore you intend to run.

Installing the tube end

Use fully annealed tubing that is softer than or equal to the fitting material, with a clean, scratch-free outside surface. Push the tube firmly onto the shoulder inside the body, finger-tighten the nut, then turn it one and one-quarter turns with a wrench for 1/2 in. size and check pull-up with the correct Swagelok gap inspection gauge. The catalog states that no torque is transmitted to the tubing during installation and that connections can be disconnected and retightened. Depressurise before adjusting any fitting, and do not mix ferrules, nuts or bodies from different makers: the catalog notes there is no industry design standard for two-ferrule tube fittings.

Where the SS-810-1-8 is used

A 1/2 in. tube to 1/2 in. NPT male connector is one of the most common fittings in instrumentation and small-bore process systems. Typical positions include the outlet of an instrument isolation valve or manifold, the process connection of a pressure transmitter or gauge, sample lines from a pipe tapping to an analyser, chemical injection lines, hydraulic and pneumatic supply headers, and utility lines for nitrogen, instrument air or cooling water on skids.

Why 316 stainless steel suits Gulf sites

In Oman’s oil and gas fields, refineries, desalination plants and coastal utilities, fittings are exposed to heat, sand, humidity and salt-laden air. 316 stainless steel contains molybdenum, which gives it better resistance to chloride pitting than 304 stainless steel, and it is the usual default material for instrument tubing systems in these environments. In very aggressive offshore or splash-zone conditions, operators sometimes specify higher alloys; in that case the material prefix of the part number changes, and the requirement should be stated in the enquiry.

Good practice for leak-free connections

• Cut tube squarely and deburr inside and outside before insertion.
• Keep fittings capped in storage so sand and dust do not enter the body or damage the ferrules.
• Apply thread sealant to the NPT end only, keeping it off the first thread so it does not enter the system.
• Support long tube runs with clamps so vibration is not carried into the fitting.
• Use the gap inspection gauge on initial make-up and keep spare gauges with the installation crew.
• For reassembly, tighten the nut to its previously pulled-up position and then slightly snug it with a wrench.

What to include in an RFQ

• Part number SS-810-1-8 exactly, plus any suffix such as CP or BQ.
• Quantity and whether spare nuts and ferrule sets are required.
• Tubing size, wall thickness and material if tubing is also needed.
• Any project material certificates or traceability documents required.

Documents and quotation

The reference for this page is Swagelok catalog MS-01-140, Gaugeable Tube Fittings and Adapter Fittings. It holds the ordering numbers, dimension tables, pressure ratings and installation steps summarised above, and is attached for download. Send SS-810-1-8 with the quantity and any cleaning or packaging option and we will quote.

Before ordering, please confirm the part number, tube size and thread type against the attached catalog, as nearby codes differ by one character. Related items: product category.