One of the most difficult jobs is to produce the correct. The bolts or the flange shall be numbered with the cross bolting pattern sequence to be used. Bolts, screws and nuts with british standard whitworth threads rationalized series. Aws structural bolting inspection endorsement building. The step by step guide will also explain the machinery and process required in different stages of manufacturing. The energy taken to twist the nut up the thread of the bolt measured. Fletcher and company huntington, west virginia usa abstract. Hydratight offers safe, online bolt renewal or hot bolting services on all asme flanges.
Robertson, mining engineer national institute for occupational safety and health pittsburgh research laboratory pittsburgh, pennsylvania usa gregory e. The process of manufacturing for bolts, screws, studs and other external threaded fasteners are explained with showing differences between bolts, screws and studs. A hot bolting operation on a heat exchanger was being conducted during startup at a gas oil hydrodesulfurization unit. Safety manuals and procedural outlines are available from the american petroleum institute api, american society. Continue this sequence until all bolts are tightened. Employs tooling with controllable outputs and adopts calculation to determine the. Joints with ring joints or solid metal gaskets of soft iron. Do not use jointing compounds or release agents on gasket flange faces.
The research program on riveted and bolted structural joints, was started through the initiative of professor w. The ctst range of manual return topside bolt tensioning. Check studs and nuts for proper size, piping material specifications and cleanliness. Obtaining a leakfree flange connection can be a difficult task onsite without a plethora of equipment to fall back on. Tightening of structural joints fasteners bolting categories 8. Wi lson prior to the organization of the illinois cooperative highway research program and has extended over a period of twenty years. Candidates seeking the aws structural bolting inspection endorsement shall pass a openbook written examination on structural bolting inspection consisting of at least 40 multiple choice questions in two hours. Using hot taps for in service pipeline connections contd exhibit 2. Installation and inspection of high strength bolts in the building construction industry while high strength bolts are one of the most important elements of the structural system of modern steel frame buildings and other structures, their installation is frequently misunderstood. Guideline for bolted flanged joint assembly in process.
Integrity assessment of hot bolting tool international. Presenting timetested standard as well as reliable emerging knowledge on threaded fasteners and joints, this book covers how to select parts and materials, predict behavior, control assembly processes, and solve onthejob problems. Examining the process of hot bolting hot bolting is a controversial approach to tightening or replacing a bolt or flange on a pipe that is live full of hot liquid or gas. List the qualifications of the head state inspector. Structural steel bolting illinois department of transportation. Since the conrect internal tension is a function of the change in length of a bolt, this tensio. Bolting in rock is a permanent act, one that affects every climbers experience forever. A proper gasket installation, bolts with correct tension, and an evenly divided bolt strength must be adhered to to create a good flange connection. Start the tightening procedure by lubricating the nuts and bolts. Education training bolting inspection experience bolting experience f. Screwed, flanged, or clamped pipe manual hydraulic shears mechanical bolting or pipe cutting compressed airactuated fasteners hot work safety continued tm. Visually examine and clean flanges, bolts, nuts and washers. The paper addresses a part of the integrity assessment of the new hot bolting tools. Then hand tighten till they are snug against the flanges.
Hot work hazards can be avoided if there is an alternative method to complete the job. The 5 step guide to torque tightening for leakfree flange. The dangers of hot bolting at the very least is a severe injury. Specification for the purchase of structural bolts and. Manager engineering 10 january 2007 uncontrolled on printing page 4 of 10 asnzs 2451. A risk assessment shall be performed prior to hot bolting to confirm the flange will not leak or fail during the procedure. How bolts screws studs and other threaded fasteners are made. Personally, i think even a descent trail is far less offensive than a bunch of man made metal hanging off. A hotbolting operation on a heat exchanger was being conducted during startup at a gas oil hydrodesulfurization unit. Unless specified by customer requirements all bolting will be per exhibit a. If an air wrench is used make sure the pressure is set to the minimum. The purpose of this hot bolting procedure is to provide minimum. Clean flanges and check for scars on the flange surface area check studs and nuts for.
Rock bolting article about rock bolting by the free. Although most flanges are designed to keep integrity in case of removal of one bolt, this requires that the remaining bolts are of such quality that they can sustain the connections total loading and maintain the gasket stress. The bolts must average a minimum of at least 5% over the required pretension. Qualification of new hot bolting tools was carried out by the joint efforts of producer, operator and classification society. Structural bolts installation as41001998 working definitions torque is not used as a measure for the tensioning of structural bolting. Morsafe online bolt renewal services english hydratight. It examines key issues affecting bolting in the automotive, pressure vessel, petrochemical, aerospace, and structural steel industries. Connection transmits the force by friction produced between the faying surfaces by the clamping action f the bolts. Onsite technical procedure has to be read and understood. The general manager, quality manager, engineering manager. In many documented accidents where hot bolting failed, there have been fatal casualties, fire, explosion, and loss of equipment and plant. It must also be able to withstand the temperature and pressure to which it will be subjected.
Hot bolting is the act of tightening a bolted connection while the bolted joint assembly flangeheat exchanger manway is in operation. Successful candidates must correctly answer 72% of. Is a daily diary maintained by the state head inspector. Rock bolting and soil nailing for luxury villa construction on peter island, british virgin islands, by keller group profits rise gives keller group new confidence applications for the cpa include pipeline trenching, utility work, anchoring and rock bolting, rough terrain construction, and long reach work.
Slipcritical connections are recommended for joints subjected to stress reversal, severe stress fluctuation, impact, vibration or where slip is objectionable. The purpose of this procedure is to outline the process of bolting procedure. Their application would extend the hot bolting operation, increase the safety and simplify the working process. As with every bolt pretensioning method, turnofnut may only be performed after all steel plies in a connection have been drawn into firm contact, i. All connections are to be installed, tightened and inspected in accordance with the latest issue of the specifications for structural joints using a325 or. Tonisco system oy is over 45year old finnish company specialized in hot tapping and line stopping. Hot bolting is the sequential removal, cleaning and replacement of bolts in a flanged joint, while the system is pressurized. These services are performed without any damage, leakages or interruptions in daily production. Hot bolting allows for corroding studs and nuts to be removed as part of preventative maintenance while the line is in service. The following is a sample bolting procedure using a manual or hydraulic torque wrench. Hot bolting procedure section d chapter 31 version. A guidance procedure for the removal and replacement of flanged joint bolting on live piping and equipment factors affecting the use of metric bolting in lieu of inch bolting in classdesignated pipe flanges.
This 2016 edition of the structural bolting handbook is based principally upon the june 2014 edition of the rcsc specification for structural joints using highstrength bolts, cited by the 2010 aisc specification for structural steel buildings aisc 36010. Highstrength bolting, engineering journal, american institute of steel construction, vol. Structural bolting handbook, 2001, steel structures technology center, inc. Tonisco has a wide range of hot tapping equipment for various needs. Thoroughly clean the flange faces and check for scars. Our expertise and experience in tension and torque has created a company with unrivalled technological and process leadership in bolt tightening.
Examining the process of hot bolting hot bolting is a controversial approach to tightening or replacing a bolt or flange on a pipe that is live full of hot liquid or. Inspection of bolting observation of bolting operations shall be the primary method used to confirm that the procedures, materials, and workmanship incorporated in construction are those that have been specified and approved for the project. Patriot internationals specially designed hot bolt clamp provides an external clamping force to maintain the joint integrity whilst the hot bolting procedure is undertaken. With tensioners, the action is not directly on the nut. Turnofnut bolting method applied bolting technology. Structural steel bolting the installation of fasteners in bridge connections is a critical element in the proper behavior of the structure. It might seem like common sense to not tighten bolts containing hot fluids or gases, but supporters of this practice often say, we always did it that way. Bolting procedures lubrication lubricating the bolt was mentioned earlier as one of the variables that would reduce the k factor. Measure the bolt length, the distance from the end of the bolt to the washer face at the bolt head to shank interface. Field manual for structural bolting state of michigan.
Rock bolting article about rock bolting by the free dictionary. Bolting procedure for steel structures tgn weld australia. Install the bolt in the tension calibrator with the required spacers or washers so that the bolt stickout is flush with the nut to a maximum of three threads. Steel structures tightening procedures bolted and riveted. All connections are to be installed, tightened and inspected in accordance with the latest issue of the specifications for structural joints using a325 or a490 bolts for slip. Schematic of hot tapping procedure are also available that allow a hot tap to be performed by a single operator, without additional blocking or bracing. The combined effects of bolt relaxation, approximately 10% during the first 24 hours after installation, gasket creep, vibration in the system, thermal expansion and elastic interaction during bolt tightening contribute to torque loss.
Examining the process of hot bolting aztec bolting. Today, hydratight has manufacturing facilities in four locations on two continents. The lubricant must be the correct one for the bolt material being used. The energy taken to twist the nut up the thread of the bolt measured in nm.
However, significant changes regarding structural bolting were implemented by the 2016 aisc specification for structural steel buildings. Introduction the turnofnut method shall be the bolt installation procedure used by medford fabrication for pretension bolts. Our clamps are not restricted to 4 or 8 bolt flanges. Lubricate the bolts, nuts and nut bearing surfaces.
Direct tension indicators dtis are special washers with raised protrusions figure 12 on. The earlier version of the model specification for the purchase of structural bolting assemblies and holding down bolts may be used for nonce marked bolting assemblies. The editors have successfully created a useful rather than scholarly handbook with chapters written in a straightforward, howtodoit manner. The dangers of hot bolting fluid sealing association. This hydratight system is a safe and secure solution that allows bolt replacement on a 4bolt. In the field, however, it would not be feasible to measure the. The nominal size of the bolt holes other than holes in a base plate shall be 2mm larger than the nominal bolt diameter for a bolt not greater than 24mm in. At least trailserosion can be reversed over time if they become a problem. This hydratight system is a safe and secure solution that allows bolt replacement on a 4 bolt.
When tightening, always use the correct sequential bolt order for the flange. All flange sizes have the posibility for failure when disturbed during a hot bolt procedure. While bolting standard practicehas remained fairly consistent over the years, there have been some recent changes thanks to new research and innovation in fastener products and specifications. Tightening torque is not influenced by the bolt length so. A rotational capacity test consists of 2 assemblies. The colour coding system shall identify the diameter of the fastener and the type of protective. Torque procedure this document defines general requirements for assembly of flanged joints in piping systems where controlled tightening of stud bolt using torque measurement is mandated. Fugitive emissions from piping systems and other equipment.
Inspection for the bolt itself is possible even after tightening. The gasketretaining ring slipped during this operation, causing a massive explosion and the loss of 17 lives. Hot bolting allows for corroding studs and nuts to be removed as part of. The first pass, lightly tighten the first bolt then move directly across or 180 degrees for the second bolt, then move14 turn around the circle or 90 degrees for the third bolt and directly across for the fourth. Bolting seminar 7 of 12 sample bolting procedure continued joint preparation 1. What type of bolt installation inspection forms are used to record the information. Bolts, screws and nuts with british standard whitworth threads rationalized. When carrying out the potentially dangerous procedure of exchanging. Guideline for bolted flanged joint assembly in process plants.
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