Tight Rubber Gasket

  • Didier Vassal, Vice President OEM and Maritime Services at Victaulic, compares the flanged and grooved pipe-joining methodologies and explains the advantages that grooved pipe joints provide over flanges. 
    Efficient piping systems are essential for the range of services needed on board a vessel including secondary systems such as bilge and ballast systems, sea and fresh water cooling, lube oil, fire protection and deck wash.
    For these systems, where piping class permits, an effective pipe-joining alternative to welding/flanging is the use of grooved mechanical joints which offer a range of technical, economic and practical benefits. These include enhanced performance; faster, simpler installation and maintenance and weight reduction on board. 

    Performance Issues
    In a flanged pipe joint, two mating flanges are bolted together and compress a gasket to create a seal.  As the bolts and nuts of a flanged joint absorb and compensate for system forces, over time the bolts and nuts can stretch and lose their original tightness due to pressure surges, system working pressure, vibration and thermal expansion and contraction.  When these bolts experience torque relaxation, the gasket will lose its compressive seal, which can result in varying degrees of leakage.
    Depending on the location and function of the piping system, leaks can be costly and hazardous, resulting in maintenance/repair downtime and exposure to risk.  Gasket replacement will be required when the joint is taken apart, as the gasket will bond to the flange faces during the course of time. When the joint is disassembled, the gasket will need to be scraped from both flange faces and these surfaces will need to be cleaned before the gasket is replaced, again increasing maintenance downtime. Due to the bolting forces along with system expansion and contraction, flange gaskets can also develop compression “set” over time, presenting another cause of leakage.
    The design of a grooved mechanical pipe joint overcomes these performance issues.  A groove is first formed in the pipe end and the piping connection is secured by a coupling which houses a resilient, pressure-responsive elastomer gasket. The coupling housing fully encloses the gasket, reinforcing the seal and securing it in position as the coupling engages and forms a positive interlock into the pipe groove.  The latest coupling technology enables pipes up to 24” (600mm) in diameter to be fully assembled with only two nuts and bolts in order to secure the self-restraining joint.  The mechanical joint creates a triple seal due to the design relationship between the pipe, gasket and housings, which is enhanced when the system is pressurized.

    Rigid and Flexible Couplings
    Available in both rigid and flexible forms, grooved mechanical pipe couplings are Class Society Type Approved, and may be used in lieu of welded/flanged methods in 30 systems, subject to installation criteria established by each certifying agency.
    Rigid couplings are used, for example, around areas such as manifolds and valves, where they offer easier access and replacement than flanges. By nature of their design, rigid couplings also provide axial and radial rigidity comparable to flanged or welded joints. 
    Flexible couplings have advantages in applications where relative movement between the pipe and supporting structure is anticipated, in addition to pipe movement resulting from thermal expansion or vibration. Expansion and contraction can stress the flange and piping, which can compromise the gasket over time. When this occurs, the joint is at risk of leaking. Grooved flexible couplings can accommodate pipe displacement in the form of axial movement or angular deflection.  For this reason they are ideal for installing long piping runs especially between blocks where high seas can cause flanges to loosen over time, resulting in leaks and the risk of pipe separation. Both rigid and flexible couplings also provide the benefit of noise and vibration attenuation, eliminating the need for specialised noise reduction components and perishable rubber bellows or similar items.
    Using a mechanical grooved piping system can speed up and simplify both installation and maintenance and improve the efficiency of onboard piping systems. 

    Ease of Installation
    On initial installation, bolt holes of a flange must be precisely aligned and then tightened to hold the joint. The bolt-hole index on equipment inlets and outlets must also line up perfectly with the flange on the piping to be connected to the unit. With only one of a number of fixed positions determined by the number of holes in a flange, a fitting or valve can only be rotated to match the bolt holes. Additionally, the opposite end of the flanged pipe must also line up with its mating flange, which further increases assembly difficulty and the risk of misalignment.
    Grooved piping systems do not have this problem and allow much more convenient installation with a full 360-degree rotation available for the pipe and mating components. There is no bolt-hole pattern to line up, and a coupling can be oriented at any position around the joint. The coupling can be rotated around the pipe to provide easy access to the bolts and simplify access to the equipment.
    In addition to eliminating misalignment during installation, a coupling’s 360-degree orientation capabilities, together with its smaller profile compared to a flange, make the installation of grooved systems ideal for confined spaces.
    Additionally, the installer can orient all of the assembly bolts on each joint in the same position to ease system inspection and maintenance.
    Flanges are roughly twice the outside diameter of the pipe they are attached to.  On average, grooved couplings are only half this size. The size advantage of the smaller design makes the grooved system ideal for jobs where space is limited, such as deck and wall penetrations - a fact recognised as far back as the 1930s when Victaulic couplings were originally used in U.K. shipyards.

    Speed of Assembly
    Because couplings have fewer bolts and no torque requirements up to 12” (300mm), grooved piping is much faster to install than flanging. Unlike flanges that must be welded to the pipe end, grooved valve assemblies do not require welding, which further cuts installation time and eliminates potential heat damage to the valve while also reducing safety risks by eliminating hot works.
    A comparison of a DIN 150 ballast line installed using Victaulic grooved products versus traditional joining methods showed a 66% reduction in total installation time required (150.47 man hours vs. 443.16 man hours).  The time needed to install 52 slip-on flanges and weld elbows and tees compared with 60 rigid couplings showed the largest time differences.
    Couplings require just two bolts up to 24” (600mm) pipe size. For comparison, at the higher size range a flange would require a minimum of 20 sets of nuts and bolts.
    In addition, flanges require time-consuming star pattern tightening with specialised wrenches to measure and ensure that correct torque specifications are achieved. Grooved pipe technology allows couplings to be assembled using  standard hand tools and the joint is properly installed once the mating bolt pads of the coupling housings meet metal-to-metal.  A simple visual inspection confirms correct assembly.  Flanges, on the other hand, do not provide visual confirmation: the only measure to ensure proper assembly is to fill and pressurise the system, check for leaks and retighten the joints as needed.


    The same characteristics of grooved piping systems that accelerate installation—fewer bolts and no torque requirements — also make system maintenance or alteration a quick and simple task. To gain access to a pump or valve, for example, the two bolts of the coupling are loosened, and the housings and gasket are removed from the joint. In a flanged system, multiple bolts need to be removed. The same time-consuming bolt-tightening sequence required upon initial installation is also required upon reassembly of the flange.
    Because they do not require retightening, couplings eliminate much of the routine maintenance associated with flanges.  Unlike a flange that puts variable stress on the gasket, nuts and bolts, a coupling holds the gasket in precise compression from the outside of the pipe joint. Additionally, since coupling gaskets are not subjected to high compressive forces, they do not need to be replaced on a regular maintenance schedule, while flange gaskets need to be replaced when the system is disassembled for maintenance.
    To attenuate system noise and vibration, flanged systems require rubber bellows or braided flexible hoses.   These items can fail due to overextension and, with normal wear, need to be replaced every 10 years on average, incurring cost and system downtime.   Mechanical grooved pipe couplings, however, last the life of the system.  Their ability to accommodate system vibration reduces the risk of joint failure, without the need for speciality products that require periodic repair or replacement. The resilient elastomeric gasket contained within both flexible and rigid couplings is very durable and can handle significant operating pressures and cyclical loading. A system can be pressurized and depressurized repeatedly without fatiguing the elastomer gasket.

    Weight reduction

    Valve assemblies are typically constructed with flanged components. However, this joining method can add unnecessary weight to a piping system. A 6” (150mm) flanged valve assembly constructed with a lug butterfly valve, connected with weld-neck flanges and eight bolts and nuts on each side of the valve, weighs approximately 85 lbs.  A 6” (150mm) valve assembly that utilizes a grooved-end butterfly valve, grooved-end pipe and two rigid couplings to connect the components weighs approximately 35 lbs, representing a 58% weight reduction over the flanged assembly. A grooved valve assembly is therefore, an ideal alternative for the shipbuilding industry.  
    The above-mentioned comparison of a DIN 150 ballast line installed showed  a weight reduction of 30 percent (2,164 lbs vs. 3,115 lbs) when Victaulic grooved products were used instead of traditional joining methods.  The 52 slip-on flanges, bolt sets and gaskets, versus 60 rigid couplings accounted for major weight increases in the welded/flanged system.  
    Weight reductions by using grooved pipe couplings instead of flanges are achievable across a range of pipe sizes. The magnitude of the reduction depends on the pipe diameter and type of coupling used.  In tests where piping was connected using one Victaulic Style 77 coupling – the heaviest coupling in the range – compared with two light-weight PN10 slip-on flanges the total installed weight of the grooved assemblies was significantly lower.  Weight reductions were recorded as follows: 4” (100mm) – 67 percent; 12” (300mm) - 54 percent; 20” (500mm) – 60.5 percent. 
    With the lighter-weight flexible Style 75 or rigid Style 07 couplings and/or a heavier type of flange, weight reductions of 70% are easily achievable.  As an example, a 24” (600mm) flanged set for a TG2 system would weigh 507 lbs but a comparable assembly using Victaulic couplings would weigh only 88 lbs.  Shipyards that have used grooved couplings in preference to flanges on selected systems have recorded weight savings of 12 tons on offshore support vessels and 44 tons on cruise ships.
    The economic benefits of grooved technology to ship owners are clear: less weight means more cargo or passengers and less fuel consumption.  It makes the handling of piping systems on board easier as well.   

    Growing Trend

    Grooved piping systems can offer significant advantages over their flanged equivalents because of their speed of installation, maintainability and reduced weight.  These characteristics, coupled with additional benefits such as reliability, ease of alignment and lower safety risks, are leading owners, engineers and shipyards to choose grooved mechanical systems instead of flanges.
    This growing trend towards the use of grooved technology is supported by suppliers of equipment such as heat exchangers, box coolers and chillers, along with valve and compressor manufacturers, many of whom are now providing their products with grooved end connections.  The range of services where grooved pipe couplings may be used is steadily increasing. Building on successful applications in water systems, Victaulic is continuing its long history of innovation to develop fire-resistant gaskets and gain Type Approval for their use on maritime fuel services.  

    (As published in the April 2014 edition of Maritime Reporter & Engineering News - http://magazines.marinelink.com/Magazines/MaritimeReporter)

  • compressed asbestos gaskets. Positive seating is achieved with no metal-to-metal contact to cause friction and wear. The flow in the piping is sealed tight on both sides with an open space in between. "To inspect for leakage," explained Mr. Daniels, "you just take a quick glance into the open space

  • field installation and increased flexibility. A large selection of springs is available to handle a wide range of applications and pressure drops. Seat tightness is precision engineered to provide the same low leakage characteristics as single seated, unbalanced valve designs. The bonnet gasket is spiral

  • Victaulic developed a new nitrile gasket for the maritime industry: the Grade T “Type A” gasket, designed for use with specific Victaulic couplings and flange adapters, and designed to simplify gasket specification and offers superior fire-resistant performance. The nitrile Grade T Type A gasket can be

  • to both sides of the penetration, also cures to a rubber-like mass that withstands tremendous pressures, enabling it to achieve its gas and watertight ratings. Milcom selected the RISE system for several reasons. "First and foremost, I'm confident that RISE offers the best fire-stop protection

  • tanker and shoreside service. The valves handle high-pressure drops in either throttling or on/off service and will maintain flow characteristic and tight shut-off and start-up through cool-down and defrost. Other key features include: positive guiding, for accurate control and reduced trim wear

  • —Literature Available According to Clemco Industries, Burlingame, Calif., the Clemlite™ system of abrasive blast hoses, couplings and nozzles can heighten productivity by lightening operators' loads by as much as 62 percent, while offering improved safety and economy. Combining ultra-light weight wi

  • Victaulic, a manufacturer of mechanical pipe joining systems, introduces Vic-Press, an IACS-approved flame-free press system for joining small-diameter stainless steel pipe. With Type Approval certification from IACS member agency Germanischer Lloyd, Vic-Press offers a quick, simple, safe and reliable means

  • Jim Scott, who was instrumental in the development of the conical seal in the 1950s, founded Seco Seals, Inc. in 1969 to fill the need for conical seals for 37 degree flared tube fittings. Since then, the company has become the standard for 37 degree flared tube fitting seals for every application, from

  • An energy-saving device that replaced steam traps on U.S. Navy ships won a $25,000 prize for the inventor, a civilian employee of the Navy, at a ceremony on the White House lawn. President Carter made the presentation to Lawrence L. Guzick for a constant flow Drain Orifice that is saving the U.S.

  • use pressure resistant materials such as thermoplastic rubbers to add buoyancy Fiber optics are processed in several different configurations including tight buffered constructions reinforced with aramid fiber and fiber optics encapsulated inside hermetically sealed stainless tubes. Both the plastic and

  • , access hatches allow easy repair or replacement of the propulsion units Vertically layered rubber fenders grip a steel hull like fingers, maintaining tight control yet easy disengagement with very little abrasion Two GM Detroit Diesel 16V-71N engines generate 1,070 hp, and are splayed 15 degrees off

  • MN Oct-16#59  function for their semi-auto-
tight, ABYC-compliant and fully)
    October 2016 - Marine News page: 59

    global Extreme Boat Lifts from duced a new reverse part number safety standards worldwide. Water- Golden Boat Lifts lookup function for their semi-auto- tight, ABYC-compliant and fully Golden Elevator Lifts are ideal for ca- matic and robotic MIG gun online corrosion-resistant, they come in nals, embankments

  • MN Oct-16#57  of instrumentation and 
very tight spaces.       
    October 2016 - Marine News page: 57

    pany’s QSK95 engine is a modular ting solution and can be ? tted into ter separators is ideal for workboats. selection of instrumentation and very tight spaces. www.Mini-Brute.com control panels engineered to help www.stonemarineseals.com marine operators protect and en- hance engine operation

  • MN Oct-16#46  and meet such an impossibly tight timetable? By 
sion to)
    October 2016 - Marine News page: 46

    How was MARTAC able to overcome the propeller supply propellers that they need, so MARTAC made the deci- bottleneck and meet such an impossibly tight timetable? By sion to design and build propellers themselves. As part of leveraging the facility of the HydroComp PropCad software this new in-house

  • MN Oct-16#12  
remarkably. It is a very tight market and there is ?)
    October 2016 - Marine News page: 12

    services, platform decommis- President, sioning, offshore towing, etc. and this business has slowed American Salvage remarkably. It is a very tight market and there is ? erce competition for the work that is available. Concurrently Association in the U.S., there is the added pressure of increased

  • MT Oct-16#58  Handling System
Working to a tight deadline, Red Marine delivered)
    October 2016 - Marine Technology Reporter page: 58

    applications, with the possibility of cutting softlines up to 350mm and more. www.allspeeds.co.uk Photo: Allspeeds Clamp Handling System Working to a tight deadline, Red Marine delivered a Subsea Clamp Han- dling System on an eight-week fast-track project for a U.S. based pro- vider of subsea riserless

  • MR Sep-16#62 MR
Products & Services)
    September 2016 - Maritime Reporter and Engineering News page: 62


  • MR Sep-16#34  Giant 
Holds Firm in a Tight Market
Tokyo-based Nippon)
    September 2016 - Maritime Reporter and Engineering News page: 34

    oices NYK NYK Maritime & Logistics Giant Holds Firm in a Tight Market Tokyo-based Nippon Yusen Kaisha (NYK) Group is not only one of the world’s largest ship owners with a diverse fleet of more than 800 ships, it is a growing global mari- time logistics powerhouse. Mari- time Reporter & Engineering

  • MR Sep-16#19  yard addressed customer  very tight schedules. ing in people)
    September 2016 - Maritime Reporter and Engineering News page: 19

    deck and signi? cantly aids the cal for any shipyard, so too is invest- o 23 days Dry Dock on Floating Dry This year the yard addressed customer very tight schedules. ing in people, and to that end GBSL Dock No. 2 demand by upgrading workshops, pur- • Manitowoc 1800 Crane gives announced strengthening

  • MN Sep-16#46 ech file
Sennebogen 870 Material Handlers: 
    September 2016 - Marine News page: 46

    ech file T Sennebogen 870 Material Handlers: Versatile, Powerful and Reliable Material Handlers provide critical link in Hudson River PCB Remediation opper barges are used for a wide range of applications; down the river ? lled with dredged sediments and water re- from grain carriage to bulk commodities

  • MR Aug-16#107  time he was able to work in tight  They were able to repair)
    August 2016 - Maritime Reporter and Engineering News page: 107

    Guam by Viega on how to install Viega connections with a battery tool. During ? ttings and responded with urgency. this time he was able to work in tight They were able to repair the pipe with- areas and not disturb cables, insulation out the need to “go dark.” They built a and ? nished areas. After

  • MR Aug-16#106 . areas were located in very tight areas, so 
and safe way)
    August 2016 - Maritime Reporter and Engineering News page: 106

    penetrations. Some threading. Viega offers a quick, reliable ratio between markets. Military repre- and MRO solutions. areas were located in very tight areas, so and safe way to install piping, while al- sents 30% of our sales, with Commercial the pipes had to be cut and placed above lowing the

  • MR Aug-16#60  to make everything ?  t in the tight avail- The Astican Shipyard)
    August 2016 - Maritime Reporter and Engineering News page: 60

    tailor-made for each vessel shipyards. Marine in Port of Tenerife, which is al- modernized and updatd its facilities. to make everything ? t in the tight avail- The Astican Shipyard in Las Palmas ready opened. Dredgers, tankers, sup- The latest investment program at As- able spaces. Pipes had to be

  • MR Aug-16#52  insu- bow thruster enable tight maneuvering,  suring 405)
    August 2016 - Maritime Reporter and Engineering News page: 52

    vectorable with a capacity of 120,000 tons and mea- and which would incorporate high-speed speed, with using special high-tech insu- bow thruster enable tight maneuvering, suring 405 m x 66 m, which is a strong engines, a clutch between thruster and lation materials on deck and bulkheads and the vessel

  • MT Jul-16#68 MTR 100
management solutions, connectors as 
Seco Seals)
    July 2016 - Marine Technology Reporter page: 68

    MTR 100 management solutions, connectors as Seco Seals, Inc. Shark Marine well as other custom products. Shark Jim Scott, who was instrumental in the Canada-based Shark Marine Tech- Marine’s MAKO diver delivery sys- development of the conical seal in the nologies Inc. develops and delivers in- 1950s

  • MT Jul-16#43  pipes (like the ribs of ?  sh  tight sandstone or carbonate)
    July 2016 - Marine Technology Reporter page: 43

    acid to extend a series of option for shale, the system is ideal for ership says. The company says getting nozzle-ended pipes (like the ribs of ? sh tight sandstone or carbonate akin to that in early with its front-end engineering; bones) from the casing along a length found in the North Sea and the

  • MN Aug-16#88  and maintenance in tight  Shipyard, Gunderson Marine)
    August 2016 - Marine News page: 88

    allow 360 degrees of rotation, easing Bristol Harbor Groups, Corn Island in four tracks. Tracks offered include installation and maintenance in tight Shipyard, Gunderson Marine, Halter Marine Culinary Management, Ma- spaces, reducing the size of wall and Marine, Moran Towing Corporation, rine

  • MN Aug-16#54  
It takes a tough man to run a tight enterprise. At least )
    August 2016 - Marine News page: 54

    underway in the Gulf of Mexico. transportation industry unless you are safe. As a company Bouchard Transportation Co., Inc. It takes a tough man to run a tight enterprise. At least we still have one goal: Zero spills, zero injuries and zero that’s the way an unapologetic Morton S. Bouchard III damages.

  • MN Jul-16#58  
eliminates over and under tight-
ening, which can lead)
    July 2016 - Marine News page: 58

    Gauge Superlok’s tube ? tting with a self- measuring gauge installed on each ? tting and compression end valve eliminates over and under tight- ening, which can lead to replace- ment expenses and worker safety concerns. Improperly tightened ? t- tings account for most connection Electronic

  • MN Jul-16#51 VESSELS
Marquette Z-drive Towboat from Master Marine 
by a)
    July 2016 - Marine News page: 51

    VESSELS Marquette Z-drive Towboat from Master Marine by a pair of Thompson Power Systems Caterpillar C32 Tier 3 1,000-hp engines at 1,800 rpm connected to ZF Ma- rine ZF AT 5111WM-FP Z-drives with 1,650 mm (65”) 4-bladed propellers in nozzles. The package gives the boat a running speed of 10 knots with

  • MN Jul-16#28   maneuverability was super tight but it was still easy)
    July 2016 - Marine News page: 28

    to a speed proximately eight to 10 degrees). The actual radiuses and of eight or nine knots,” says Guarino. “After that, they maneuverability was super tight but it was still easy to steer the boat.” would start contributing to the resistance instead of help- Pre-Swirl Stators reduce the rotational losses

How Watertight is Your Company’s Integrity)
    July 2016 - Marine News page: 20

    REGULATORY COMPLIANCE How Watertight is Your Company’s Integrity? A watertight boat is a beautiful thing. It keeps you a? oat in heavy seas. Can you say the same for your company’s integrity? By Captain Katharine Sweeney Vessels are built with speci? c hull and environmental protection policy which

Preparing for New Fire-Fighter Regulation)
    July 2016 - Maritime Reporter and Engineering News page: 44

    MARINE ELECTRONICS Preparing for New Fire-Fighter Regulations New SOLAS resolution mandates change to ? re-? ghting communication systems. Will you be ready? BY NIELS PETER AGDAL & CLAUS HORNBECH n November 30, 2012 the during ? re-? ghting operations or if the Maritime Safety Commit- Fire Party

  • MR Jul-16#21  onto  constraints given the tight operating margins that)
    July 2016 - Maritime Reporter and Engineering News page: 21

    to wind and weather cluding Cargo, Project Cargo, Hull & Machinery, Ter- tainers will no longer need to be moved/reloaded onto constraints given the tight operating margins that these minal Operators, and related Inland Marine LOB’s. trains. The fewer times you have to handle a container ships will

  • MR May-16#78 MR
Products & Services)
    May 2016 - Maritime Reporter and Engineering News page: 78