Flange Cuff Vision

The Flange Cuff was engineered to provide our clients a safe efficient way to successfully hot bolt 4-bolt flanges without shutting down production.

The Flange Cuff comes in 2 frame sizes with inter-changeable teeth to accommodate 1", 1 ½", 2" and 3" flange diameters and fits 150# raised faced flanges. The compact chain-like design allows for easy access to flanged connection in tight areas.

The Flange Cuff was designed to meet the minimum allowable stress values in accordance with ASME B31.3 and ASME Sec. VII, Div. 1.

Our state-of-the-art technology has assisted our clients to remain in compliance with regulatory agencies and maintain production incident free.

The Flange Cuff has successfully changed over 1600 4-bolt flanges without incident or loss of production for multiple clients in the Gulf of Mexico.

Flange Cuff Mission

The principle concept of the Flange Cuff is to achieve the engineered torque setting on the swing bolt. The torque setting will differ on each size of a 150# flange (1"-3"), as well as being dependent on the diameter and materials of the studs.

Once the correct torque is achieved on the swing bolt, the amount of clamping force applied by the Cuff will be equivalent to the required gasket seating force.

When the required clamping force has been achieved then one stud may be removed from the flange at a time. Once the new stud is installed, it is recommended to hand tighten and torque the stud to 5 ft-lbs.

After the Cuff is removed, Each stud will need to be torqued in a cross pattern sequence according to Best Practices.

Torque Details

Earlier Versions

Generation 1

Generation 2

Revision History

  • Generation 1 & 2 Models of the Flange Cuff weren't designed for tight, inaccessible areas. It was re-submitted back to engineering to design a Cuff that could be "snaked" in to tight areas. The "chain link" design was conceived.
  • Generation 1 & 2 Models of the Flange Cuff didn't allow for a Nut Splitter to be properly placed in-between the teeth of the Cuff. The Generation 3 model was designed so that the body of the Cuff was recessed below the top of the teeth.
  • Interchangeable teeth were designed to decrease the amount of full body sizes needed on projects, as well as to better replace worn parts.
  • The swing gate stud replaced the stud and two-nut design, to reduce the potential of dropped objects when working at heights.



What are the pressure and temperature limitations?
  • As of now, with the current design of the Flange Cuff, the pressure and temperature limitations are based upon the same limitation of a 150# RF Class flange of SA-105 material. The SA-105 150# RF Class flange has a max rating of 285 psi @ 100F.
  • As temperature rises the rating of the MAOP is lowered. Because the Flange Cuff is rated upon the tolerances of the flange it is applied to, the max pressure will lower as temperature increases.
  • If a flange cuff will need to be utilized in a high temperature or high pressure scenario, then this must be sent to engineering to determine if the Flange Cuff can be used safely.
  • The Flange Cuff was design based upon "Hot-Bolting" 4-bolt flanges of SA-105 material 150# Class RF flange with A-193 Grade B7 studs with spiral wound gasket. The Flange Cuff can be used in other scenarios but will need to be proved through engineering and testing.

Is it just for the 150# flanges?
  • As of now, the Flange Cuff was engineered and designed for 150# RF Class Flanges with spiral wound gaskets. The concept of the Cuff is completed, but given the need to utilize the Cuff on different size flanges "diameter or class", different material studs or different gaskets a Flange Cuff can be made to meet those requirements.
  • Disadvantages: Flanges with a high count bolt pattern will leave little room for the Cuff teeth to grip the flange body. The Cuff will have to be engineered and tested to ensure the teeth grip uniformly and creates enough downward pressure to meet the required gasket seating force. Then more than likely, a procedure will be written or altered to account for that particular application.

Has the Flange Cuff been used in a real application?
  • Yes, the Flange Cuff has been used in the Gulf of Mexico and has successfully changed over 1600 4-bolt flanges for multiple clients.

Are all generations of the Flange Cuff available?
  • No, only the generation 3 is available.

What are the advantages and disadvantages of the current generation of the Flange Cuff?
  • One of the advantages of the Gen 3 Model is its multi-hinged design. The multi-hinged design allows the stresses of the Cuff to be distributed through-out the Cuff body. This reduces the amount of localized stress risers, which in turn allows the Cuff to be lighter.
  • Also, because of its multi-hinged design the Flange Cuff will lay flat. This enables us to fit the Flange Cuff into tight areas accessing more flanges. Where the old generations, with the single hinged design, will only allow access to the flanges that have a reasonable amount of room around the flange.
  • On the Gen 3 Module the stud was changed to a swing bolt. The swing bolt is permanently attached to the Cuff body to assist in preventing dropped objects
  • The inter-changeable teeth was conceived to reduce the amount of Cuff's needed on a job site. It decreases foot-print (space requirements), equipment day rate from the original and enables us to replace broken or worn parts easier and cheaper.
  • There are certain amounts of space requirements needed around the flange body.
  • Once a Flange Cuff has been put on, a thorough inspection needs to be completed to make sure the all of the body parts are aligned and applying pressure evenly.

How many times can the Flange Cuff be used?
  • There is no set number of times the Cuff can be used. But it does need to be inspected before each use. If the teeth look worn or there is grooving in the teeth that can be visibly seen, then that set will need to be sent back to NACHER for a thorough inspection.

Are the wedges damaged during utilization?
  • There will be slight grooving in the teeth when used multiple times. But for typical usage the teeth are not damaged.

What is the function of the swing bolt? What is the specific torque it needs?
  • Tightening the swing bolt allows the Flange Cuff to reach the required gasket seating force. A torque wrench is used to apply the torque.
  • The torque in the third column of the table below is equivalent to the amount of pressure required by the flange gasket:

How much does the Flange Cuff weigh?
  • The 1"-1½" cuff weighs approximately 35lbs.
  • The 2"-3" cuff weighs approximately 45lbs.

Is it required a specific training for the pipe fitters?
  • Yes, there will be a required training session for all users of the Flange Cuff. This can either be completed onsite, at the NACHER facility or by a training video.
  • Two training courses are available:
    • Flange Cuff Competency: 4hrs
    • Hot Bolt Principles: 4hrs
  • Since the Flange Cuff and Hot Bolting go hand-in-hand, our training accommodates for both skill sets.

Contact Us

Please contact us for pricing and availability:
  • FlangeCuff LLC
  • P.O. Box 51564 Lafayette, LA 70505
  • (337)-344-4833
  • Clayton@FlangeCuff.com

FLANGE CUFF 2016 (C). All Rights Reserved.