Instrument Fittings Technical Data

Jump to the Various Sections of this and other Instrument Fittings and Tubing Pages: Gyrolok® Tube Fittings | Interchangeability of Instrument Fittings | Instrument Fittings and Valves Engineering Data | Installation and Assembly of Instrument Fittings | Checking for Leaks in an Instrument Tubing and Fitting Assembly | Insulated Dielectric Instrument Tube Fittings for Cathodic Protection Systems | Instrument Fittings and Tubing Tools and Accessories | Instrument Fittings and Tubing Training | Instrument Tubing Data Charts | Precision Instrument Pipe Fittings | Stainless Steel Ball Valves | 10,000 psi Fittings | Thread Tape and Paste for Instrument Fittings | Instrument Fittings Useful Information | Codes and Standards | Compression Fittings | Excess Flow Valves | Instrument Manifolds, Monoflanges, Valves and Accessories | Tubing SelectionInstrument and Piping Fitting Gauging | PROCHEM Technical Information | Other Useful Fitting Information |


Technical Instrument Fitting Information from Hoke


Gyrolok® Tube Fittings

Gyrolok® Tube Fittings - The Gyrolok tube fitting catalogue has heaps of information on instrument fittings including; Gyrolok Features & Benefits, Gyrolok Design, Pipe Thread Information, SAE Fittings Information, Gyrolok Fitting Dimensional & Application Tables, Replacement Parts, Dielectric Fittings, Chromatography Fittings Tools and Accessories and RS Bonded Seals.

The HOKE Gyrolok Design - HOKE Gyrolok® Tube Fittings have been carefully designed and manufactured to provide a wide range of outstanding leak-tight application capabilities, this bulletin details the features.

Video - Gyrolok® Features and Benefits - This video details the extensive features - from UTube.


Interchangeability of Instrument Fittings

The Issue of Interchangeability - Gyrolok tube fittings are designed to be interchangeable. Hoke guarantees the functional Interchangeability of HOKE Gyrolok® fittings with similar fittings of certain other manufacturers, including Swagelok®, Parker A-LOK®, and Parker CPI.


Instrument Fittings and Valves Engineering Data

Engineering Data pertinent to Instrument Fittings and Valves - A very useful document which Includes Definitions, Liquid Flow Cv Equation, Gas Flow Cv Equation - Subsonic Flow, Chemical Resistance Chart, Industrial - Aerospace and Military Fluids, Technical and Special Properties of commonly used 'O' Rings, Conversions, Comparison of Leakage Rates in Various Units, Typical Specific Gravities and Specific Inherent Hazards on Oxygen Service.

Circle Seal Controls Corrosion Resistance Guide - This is a very useful tool.


Installation and Assembly of Instrument Fittings

UPDATED 2015 ISSUE! Fitting Installation Manual - This pocket Ebook is just the "Instrument Fittings Bees Knees" - full of fantastic information on Pipe Threads - Straight and Taper, Thread Tape and its Application, The Pipe vs. Tubing Decision, Tubing - Advantages / Variables / Derating / Care and Handling / Bending / Bending Information Charts - HOKE Gyrolok Assembly Instructions / Sizes 1?, 25mm and Smaller / Sizes 1¼?, 28mm and Larger 31 / All Sizes / Installation Aids / HOKE Safety Check List and lots more!

Video - Approved Methods for Gyrolok Initial Assembly and Remake - This excellent Gyrolok Installation Training video is a "must view" prior to attempting to install or remake Gyrolok Instrument Fittings.

Gyrolok Installation Instructions - Assembly - Initial setting of ferrules onto tubing or tube stub-ended fittings.

Hoke Gyrolok® Safety Instructions - These instructions on page 56 of this document are a must when designing, installing, commissioning and maintaining Hoke Gyrolok® fittings.


Checking for Leaks in an Instrument Tubing and Fitting Assembly

Checking for Fitting Leaks? - "Leak-Check" is utilised to detect leaks in compressed air/gases. It is non-toxic, non-corrosive and a non-flammable liquid which is effective over a wide temperature range from 0 to 76°C. It can detect the smallest of leaks in any compressed air, gas or oxygen systems undergoing pressure testing. The scientifically formulated liquid can check for escaping gases in piping, inflated equipment.


Insulated Dielectric Instrument Tube Fittings for Cathodic Protection Systems

Need an Insulated Fitting Solution in a Cathodic Protection System? - See page 47 - These dielectric tube fittings are for use in applications where electrical current flowing through a pipe or tube line must be interrupted to protect vital instrumentation and metering equipment. Commonly used in the Natural Gas Transmission industry, the dielectric fitting will prevent current flow resulting from Impressed Current Cathodic Protection Systems, static electricity or even lightning strikes, from reaching sensitive monitoring station equipment.


Instrument Fittings and Tubing Tools and Accessories

Hydraulic Pre-setting Tool - For Safe, Simple, and Cost-effective Assembly of Larger Fittings - Larger tube fittings often require more effort to assemble properly than can be consistently achieved using hand wrenches. HOKE offers a portable Hydraulic Pre-setting Tool to make the assembly of larger fittings safer, simpler and more cost efficient.

Gyrolok® Tools and Accessories - The Gyrogage and presetting tools detailed on page 50 are really useful tools for ensuring correct makeup of Gyrolok® fittings.


Instrument Fittings and Tubing Training

Training and Engineering Support - HOKE offers extensive training designed to ensure that your craftspeople thoroughly understand how a HOKE Gyrolok® fitting functions. By teaching proper tubing preparation and installation procedures, maximum performance is assured. Ask your HOKE distributor for details regarding HOKE's valve and fitting installation workshop and additional support materials. 


Instrument Tubing Data Charts

Stainless Steel Tube - Covering Seamless Stainless Steel Tube in Duplex, Monel, PVC sheathed copper tube and exotic metals. This technical article includes important subjects such as Ferrule hardness, 2.5% Minimum Molybdenum, Pickled & Passivated vs. Bright Annealed Tubing along with weights and working pressures.

Hoke Gyrolok® Tubing Data Charts - These charts are very useful and contain information on design, type of tubing, tubing preparation, calculating Yield, Burst, and Maximum Allowable Working Pressures, Maximum Allowable Stress Values for Material at Various Temperatures, Stainless Steel Calculation Factor Tables, Maximum Working/Burst Pressures and Tubing Tolerances.

Pipe and Tube - Lots of very useful information here including descriptions on seamless and welded, common pipe and tube terms, manufacturing methods, nominal working pressures, pipe dimensions and weights, tube weights and working pressures.

Useful Facts About Stainless Steel - This technical data sheet is full of useful facts and information about stainless steel.

Selection of Materials - This very useful table gives the composition of the various materials used such as 304SS and 316SS etc.

Steel Terms and Definitions - A very useful table full of terms and descriptions.


Precision Instrument Pipe Fittings

Hoke Precision Instrument Pipe Fittings - Looking for a high precision fitting manufactured with high quality NPT threads?

HOKE Gyrolok® Flanges - These Flanges are an excellent way of increasing your plant integrity. Gyrolok® flanges provide a simple, safe interface between pipe flanges and instrument fittings, eliminating the need for pipe threading or welding.


Stainless Steel Ball Valves

Stainless Steel Ball Valves - Ensuring safety is paramount and is achieved with high quality threads and materials of construction. This range of valves are of the highest quality in the market!!


10,000 psi Fittings

10,000psi Fittings Specification - This specification covers 10,000 PSI working pressure screwed pipe fittings and covers subjects such as standards, materials, design criteria, threads and tolerances, Marking and Certification.


Thread Tape and Paste for Instrument Fittings

Thread Tape and Paste - This is an essential component when installing Instrument fittings, it helps prevent galling and also assists with the "seal". It should be noted that there are different grades for various services, typically silver for Stainless Steel, yellow for gas applications by utilities and white for general plumbing. Thread Paste is a general purpose instant sealer for tapered and straight/tapered fittings.


Instrument Fittings Useful Information

 Fittings and Small Bore Tubing Systems - Handbook

This superb 72 page document from the Norwegian Oil and Gas Association covers most engineering aspects of small bore tubing and fittings. 

Unit Conversions for Fittings Applications - Some useful conversions.

Other data can be found at, some valuable technical information can be found here.

Tube and Tube Fittings - This open source book Lessons in Industrial Instrumentation by Tony R. Kuphaldt has a useful section on instrument connections has a useful section on Instrument Tube Fittings - go to page 573. This is a fantastic resource but be prepared for the 50Mbit download!

Just click on the super ICEweb links below for technical information on Instrument Tubing and Fittings.


Analytical, Instrumentation and Mechanical Heat Tracing and Tube Bundles - A Tubing Bundle consists of a small diameter tube or group of tubes packaged in an insulated, weatherproofed jacket. It may be steam or electric traced to provide freeze protection or temperature maintenance. Tubing Bundles are used in Instrument hook-up and impulse lines, Analyser sample transport, Insulated Tubing and Jacketed Tubing. This page provides many relevant free technical references to Analytical, Instrumentation and Mechanical Heat Tracing and Tube Bundles.


Codes and Standards - A useful list of Instrument Fitting and Tubing Codes and Standards.


Compression Fittings - This is "Essential" reading for any Instrument Engineer or Technician.


Excess Flow Valves - These devices are a real "Safety Boost" in that they limit flow in the event of a rupture.


Instrument Manifolds, Monoflanges, Valves and Accessories - Information on what is a great addition to an Instrument Engineers Instrument take-off design engineering arsenal. Saving potential "failure points" means enhanced safety!


Tubing Selection - Instrument Tubing has to treated with "Respect" in that there are many facets of any design of tubing systems. This page goes into great detail with many tips.


Instrument and Piping Fitting Gauging

The following excellent links are compliments of Glastonbury Southern Gage.

  • Fittings Technical Information covering NPT Pipe Threads, Sealing Theory, Pipe Nomenclature, Gauging, Indirect Measurement, Dryseal, Step Plug and Ring, Zones and Truncation Limits, Interchangability of Gauges and Straight Pipe Threads.
  • Definition of Terms- A list of terms pertaining to thread gauges.
  • Gage Criteria - Includes Standards, Reference documents and Gauge criteria.
  • Gage Allowances - A feature which must be considered is the allowance. This computed amount is subtracted from the basic pitch diameter to attain an adjusted maximum size for the external product. The purpose of this is to guarantee ease of assembling the internal and external products.
  • Thread Forms - External and Internal thread Geometry, Unified Inch Screw Threads per ASME B1.1, Federal Standard H28/2, Inch "J" Series SCrew Threads: per Military Standard, MIL-S-8879C (25 July 1991): Metric Screw Threads:per ASME B1.13M, Federal Standard H28/21, Tolerance and Allowance Grades.
  • Master Setting Plugs - Master Set Plug Gages, Thread Ring Diagnostics & Setting, Tightness of Fit
  • Use Of Thread Plug Gages - Description on the use of "Go" and "No Go" gauges.
  • Southern Style Thread Rings - This page explains the use and setting of the Southern Style Ring.
  • AGD Style Thread Rings - This page explains the use and setting of the American Gage Design (AGD) Ring.
  • Comparison Of Southern Style and AGD Ring - This page is an analysis of the differences between the Southern Style Ring and the American Gage Design (AGD) Ring.
  • Variable Thread Gages - A thread gaging system comprises a list of thread characteristics that must be inspected and the gaging necessary to inspect these characteristics to assure product acceptability. Many organizations through their quality system provide methods / systems for the inspection and acceptability of their product. ASME has set an industry standard of gaging systems for screw threads known as ASME B1.3M. These systems provide different levels of inspection to insure dimensional conformance has been achieved. Covers system 21, 21A, 22 and 23.
  • Pipe Thread History
  • Frequently Asked Questions about Thread Gauges - Some of your questions answered here.
  • Download Comprehensive Technical Book on Gauges - This is a large download >20Megs but is worth it for your library, coving all the Glastonbury Southern Gauge Technical Data it is a great resource.
  • What is a Fixed Limit Gauge? - Part 1 and Part 2 - The objective of this publication is to offer, in usable, simple terms, a basic summary, and source of information for those individuals given responsibility for the purchase and use of attribute or fixed limit gages.

Understanding GO/NO GO Gauges - (Fixed Limit Gauging) - One of the most frequent questions that we are asked at is, "how do I choose a plug gauge for my measurement application." Therefore I put together this document to help you understand the concept of fixed limit gauging. From A.A. Jansson.

The following technical information on other products are from PROCHEM PIPELINE PRODUCTS.


Instrumentation - Includes information on:

  • Anderson Greenwood
  • ATKOMATIC Solenoid Valves
  • BuTech Pressure Systems - System components are available in every imaginable alloy to handle pressures form vacuum to 150,000 PSI (10,000 bar) in tube and pipe sizes from 1/8" to 1" and temperatures from -423°F (-253°C) to over 1200°F (649°C). Suitable for extreme application of erosive or corrosive solids, liquids or gases.
  • Circor Tech
  • Circle Seal
  • Classic Filters - These filters are suitable for a variety of gas and liquid applications and are used in a wide range of industries around the world. The disposable microfibre filter elements are extremely efficient as well as being low cost. There are a number of benefits with this type of element and they offer high flow rates with very low pressure drops.
  • DOPAK® Sampling Systems - Due to the growing complexity of the industrial processes in general and more specific for processes in the (petro)chemical and pharmaceutical industries, the need for tests and analyses increases continuously. The need for representative samples plays a critical role in ensuring product verification. Yet sampling directly from the process often includes the risk of exposure to the operator, as well as contamination and pollution to the environment. The Manual Sample Systems method reduces such risks with its patented design and simple method of operation.
  • GO Regulator®
  • GYROLOK® Twin Ferrule Tube Fittings
  • HOKE® Instrumentation Valves
  • King Instrument Company - King Instrument Company offers a comprehensive line of variable area flow metres including acrylic, polysulfone, glass and metal tube metres. Optional alarms and 4-20 mA transmitter available on selected models. See more technical information on ICEweb's Flow page.
  • Leak-Check
  • Prochem NPT Ball Valves - Full Bore 2-piece threaded valves allowing straight-through flow. Virtually no head loss and a superior performer with mildly abrasive as well as corrosive fluids. Ideal for in-line control of process fluids.
  • Saddles
  • Stainless Steel Braided Hoses - Teflon® Lined
  • Stainless Steel Tube
  • Thread Tape & Thread Paste
  • Tooling
  • HOKE® Pipe Fittings

Hydraulic - Includes information on:

  • Tube-Mac Piping Technologies
  • Tube-Mac - PYPLOK System
  • Tube-Mac Non-welded Flange Connections
  • Seamless Steel Tubes
  • PYPLOK Tooling
  • Stainless Steel Ball Valves - Hydraulic
  • Stainless Steel JIC Fittings - JIC Fittings and Adaptors provide a straightforward, positive, mechanical seal. They have been used for many years for reliable sealing in commercial, industrial and military applications. They are proven to supply dependable, reusable connections under a wide range of operating conditions including extremes of vibration, temperature and shock.

Valves and Actuators - Includes information on;

  • Prochem Actuated Valve Packages - Specialising in Poyam, ATC, BSM, Pacson and Habonim - Prochem can deliver actuated valves in any combination to suit your valve, actuator and control system specification.
  • AMPO Poyam Valves - These are high-technology valves with best performance and low maintenance costs. Applications include Cryogenic Service, High Pressure, General Service, Metal Seated and Special Application.
  • BSM Valving Solutions - Emergency Fast Track Valve Producers and Delivery Specialists, providing Ultra fast deliveries. Hard to obtain valves need specialist engineering. These valves are manufactured in a wide range of exotic materials to tight specifications.
  • ATC Actuators - The heart of the ATC actuator design is the revolutionary torque conversion mechanism combined with the integrated actuator spring. The simple operating principle offers a combination of high efficiency and small displacement, thereby creating greater design flexibility and improved reliability. This design flexibility, combined with the innovative integration of all actuator parts, results in the most compact actuator available in the market. In virtually all applications, irrespective of hydraulic or pneumatic supply, the ATC actuator diameter is smaller than the Face-to-Face dimension of the valve.
  • Pacson Valves - These are high integrity valves specifically designed for the Oil and Gas Industry.
  • Anderson Greenwood Primary Isolation Valves - Anderson Greenwood Instrumentation Products provide the ultimate solutions for a compact range of forged body Primary Isolation Valves, featuring a choice of end connections, body styles and valve technology.
  • Habonim Industrial Valves and Actuators - Habonim’s new series of ZERO-Stem-Leak valves, is based on the HermetiX technology. HermetiX is a patented stem seal designed to reduce stem leaks to a minimum and to provide maintenance-free service.

Manufacturing - Includes information on:

  • Quality Management System
  • Fully Traceable and Complying Threads
  • Leaders in Thread Manufacture
  • Exotic Alloys
  • Engineered Solutions
  • World Class Manufacturing
  • Safety, Integrity and Reliability
  • Special Service
  • Standard Products - BSP Fittings
  • Standard Products - NPT Fittings
  • Standard Products - Other

Piping Products - Includes information on:

  • Branch Fittings - Details on a range of Buttweld, Socketweld, Threaded and Flanged reinforced branch fittings from 8 (1/4") NB upwards.
  • BSP Fittings - Prochem manufactures a complete range (from 6 (1/8") - 100 (4") NB) of BSP tapered, BSP parallel and BSP fastening and sealing threads for a variety of applications, in class 150 and 3000. All our BSP threaded fittings are checked with calibrated gauges during manufacture. Each batch is further confirmed as being in compliance with the international standard and before they are released into the market, all products undergo a final visual and dimensional inspection by thread profiling.
  • Buttweld Fittings - Concentric and eccentric reducers, equal and reducing tees, 45° and 90° elbows, buttweld caps and stub ends, are all part of the comprehensive range of buttweld fittings carried by Prochem.
  • Duplex Stainless Steels - Duplex Stainless Steels are unlike the 300 (Austenitic) and 400 (Ferritic) series of stainless steels in that they have a structure consisting of approximately equal amounts of both ferrite and austenite. Therefore, they are often referred to as ferritic-austenitic stainless steels. With a chromium content ranging from 18 to 28 percent, they have improved passivity compared to standard grades. The nickel content ranges from 4.5 to 8 percent which is insufficient to promote a complete austenitic crystal structure, hence the mixed ferrite-austenite structure. Most grades contain molybdenum in the range of 2.5 to 4 percent plus small amounts of nitrogen - enhancing both strength and pitting resistance.
  • Flanges - A flange is designed to connect sections of pipe, or to join a pipe to an assembly such as a pressure vessel, valve or pump. Flanges are joined by bolting, and sealing is completed with the use of gaskets, and fixed to the piping system by welding or threading.
  • Heat Exchanger, Condensor & Boiling Tubes - Useful technical datasheet.
  • Hygienic and Tube - Prochem is well established as a supplier to the food industry. A comprehensive range of BSM, Tri-clover and buttweld fittings and valves are available throughout Australia, complete with welded and annealed polished tubes to suit. 
  • NPT Fittings - NPT fittings are designed for high-pressure (class 3000 - class 6000) applications, and have a distinctive profile for maximum strength. All NPT products are checked with calibrated gauges during the manufacturing process and each batch is further confirmed as being in compliance with the international thread standard. Before they are released into the market, each item is subject to a final visual and dimensional inspection by thread profiling. Materials used comply with ASTM A403 or A182.
  • Pipe Nipples - Pipe nipples are available in ASTM A403 WP316/316L or 304/304L materials, from 6 (1/8?) NB upwards, threaded BSP or NPT, bevelled or plain ended. Prochem has the ability to manufacture pipe nipples up to 6000 mm (6 m) in length in sizes 6 NB to 80 NB.
  • Saflok Self-Locking Quick Coupler Range - Prochem provides the safest quick couplers on the market from Saflok. Included the patented locking cam arm, the Saflok design has no peer among other quick couplings.
  • Socketweld Fittings - Prochem manufactures and supplies an extensive range of the highest quality Socketweld fittings, all thoroughly inspected to ensure complete dimensional compatibility with the requirements of the ASME B16.11 manufacturing standards.
  • Swage and Pipe Nipples - Prochem manufactures, stocks and supplies a range of plain, bevelled and threaded concentric and eccentric swage nipples, from 8 (1/4") NB through to 100 (4") NB, with other sizes available on request. All swage nipples are either manufactured from seamless pipe or bar material and have an available working pressure equivavlent to straight seamless pipe. These fittings are available in ASTM A403 WP316/316L or 304/304L materials with other materials available on request.
  • Stainless Steel Shim - Grade 316 shim, annealed and with a hardness rating of HV200, is available in coiled 305 mm (12?) wide rolls, in various thicknesses and sold by the linear metre.
  • Stainless Water Solutions Package - With increased height of buildings, pressures, and life time expectations, people are turning to Stainless Steel for their Water Solutions. These pipe and fittings bear the Water Mark logo ensuring compliance to the industry specifications. Coupled with roll grooving, Prochem has the complete package to offer your Water Solutions package. All designers, architects and builders should contact Prochem to see how we can save you money!!
  • Swing and Spring Check Valves.


Welded Duplex Tube - Welded Duplex Tube to: ASTM SA789/A789 UNS S31803/S32205.

Other Useful Fitting Information

The following technical links are available via Swagelok

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