Proceedings of the ASME/USCG 2013 3rd Workshop on Marine Technology and Standards MTS2013 July 24-25, 2013, Arlington, VA, USA

MTS2013-0304

Grooved Pipe Joints on Shipboard Applications Downloaded from http://asmedigitalcollection.asme.org/MTS/proceedings-pdf/MTS2013/99403/28/2792536/mts2013-0304.pdf by guest on 30 September 2021

Douglas Dole Victaulic Easton, Pennsylvania,

ABSTRACT Grooved piping has been used on shipboard applications since the early 1920’s, first in the than many other parts of the world. It gained rapid acceptance in the UK for its many advantages over flange connections. In the US it was used on many Merchant and Naval vessels constructed during World War II, partly for its speed of installation, but also for its less fussy tolerance requirements with regard to pipe length and joint alignment. It has since grown to become used worldwide in many types of vessels. This paper enumerates grooved pipe joints advantages and its technical underpinnings.

INTRODUCTION Grooved pipe end mechanical joint systems have been employed in various shipboard applications since 1921 in the UK where the joint was originally invented and brought to market. It was initially used in the place of flanged joints for the strain relief they provide as well as space savings. With successful use and service came wider adoption around the globe of shipboard grooved pipe joints and marine class approvals.

28 Published with permission. Grooved pipe joints in shipboard applications

Originally invented just after World War One, as an improvement over low profile flanges that had been held together with “G-Clamps” used on British Large Gallery Flamethrowers, grooved pipe joints were rapidly adopted for applications onboard ships in the UK starting in 1921. UK patent 149,381, issued August 4, 1920 and UK patent 167,265, issued

August 3, 1921 teach the fundamentals of the grooved pipe joint consisting of grooved end Downloaded from http://asmedigitalcollection.asme.org/MTS/proceedings-pdf/MTS2013/99403/28/2792536/mts2013-0304.pdf by guest on 30 September 2021 pipes and a coupling which seals and secures the pipes. Shown below in figure 1 is the basic structure of the grooved joint.

PIPE GROOVES, COUPLING GASKETS AND HOUSINGS

The mechanical grooved pipe-joining system begins by cold forming or machining a groove into the pipe ends. The piping connection is secured by a coupling which houses a resilient, pressure-responsive elastomeric gasket. The coupling housing fully encloses the gasket, reinforcing the seal and securing it in position as the coupling housings engage into the pipe grooves forming a positive mechanical lock. Only two nuts and bolts are needed to secure this self-restraining joint. The grooved pipe mechanical joint creates a triple seal due to the design relationship between groove, gasket and housings, which is enhanced when the system is pressurized positively or negatively. The joint is easy-to-install, leak-free and maintenance-

29 friendly mechanical connection that provides versatility and reliability. The reasons were many.

RAPID ADOPTION BY SHIPBUILDERS

First made available for sale in 1921 in the UK, Shipyards quickly started employing the

new pipe connection. Downloaded from http://asmedigitalcollection.asme.org/MTS/proceedings-pdf/MTS2013/99403/28/2792536/mts2013-0304.pdf by guest on 30 September 2021

WASTE OF VALUABLE SPACE – In the installing of ships pipe-lines for bilge and auxiliary services, water, sanitation and so on, the engineers were often seriously concerned by the wastage in space due to the use of the conventional pipe-joints at the time. Not only were the actual dimensions of the pipe-flanges to be regarded, but there was also the further need for the provision of space to permit spannerage and fittings. Expansion had to be allowed for; a certain degree of flexibility had to be provided by some means or other. Whether the Duct Keel was used or the conventional layout was followed, the employment of the grooved joint effected economies in space, and in many cases a saving in mounting and other structural work.

PIPES LED THROUGH BULKHEADS – Where it was necessary to carry pipes through bulkheads, it was, of course, necessary to prevent inter-bulkhead leakage around the pipe; whatever the construction, the outside of the pipe had to be “sealed” to the bulkhead. A construction commonly used was the form of a double bend, bolted at its middle to the bulkhead, and provided—by its serpentine shape—sufficient flexibility to accommodate expansion. At the same time, however, valuable space was taken up and the bulkhead considerably weakened.

GENERAL SAVING – The grooved joint, in conjunction with a bulkhead adapter (Figure 2) consisting of a short tube with a central flange, saved a great amount of valuable space, didn’t weaken the bulkhead, was easy to access, flexible, and allowed free expansion and contraction. There was also a substantial saving in cost by the simplification of the surrounding structural work.

THE DUCT KEEL

Among the most important modifications, at the time, in ship structure was put forward with a view of minimizing both initial and running costs of steamers, the Duct Keel undoubtedly took a

30 prominent position. The idea itself was extremely simple, provision being made for a long continuous unobstructed passage between the outer bottom and the tank top of a vessel, in which space can be housed important pipe-lines serving the bilges and tanks of a large cargo or passenger steamer. In the case of the bulk-oil carrying vessel the space provided was used for housing the main pipe-lines. The advantages of the Duct Keel were, briefly, that it enables

bilge-lines, tank-lines, supplies and exhausts to oil-fuel heating systems, etc., to be Downloaded from http://asmedigitalcollection.asme.org/MTS/proceedings-pdf/MTS2013/99403/28/2792536/mts2013-0304.pdf by guest on 30 September 2021 concentrated in one fore and aft accessible compartment, thereby eliminating the evils attendant to the piercing of bulkheads, the running of oil and ballast suction pipes through tanks and of water and other pipes through holds. For reasons of structural strength, the duct could only be of a limited size, and it therefore became a matter of importance so to arrange the piping systems as to permit of the maximum value being obtained from the adoption of the design. With ordinary standard circular flanges, it was possible to install quite a respectable number of pipe-lines. That number could be increased by substituting for the circular flanges, hydraulic shape flanges, which had already been done in some cases, but the most advantageous results were obtained by adopting the grooved pipe joint.

The simplicity of the joint, its small diameter, its flexibility and reliability, are all points which weighed largely with progressive ship owners. From Figure 3 below it can be readily appreciated that it formed a most convenient joint for use in the important pipe passage formed by the Duct Keel. There was no doubt that the owners, who adopted the Duct Keel system of ship construction, appreciably added to its value by adopting the grooved joint.

Figure 2 – “Bulkhead Adaptor” Figure 3 – Grooved Joint Space Savings vs. with the earliest of Grooved Joint Flanged Joints Again with Type “A” Couplings Couplings Known as Type “A”

31 Below is a partial listing of UK shipyards (as of the late 1920s) that were early adopters as well as the ships fitted with grooved pipe joints on various systems of shipboard piping.

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32 EARLY MARINE USERS OF GROUNDED PIPING

WHEN BUILT AND SIZE OF VESSEL OWNERS BUILT BY USE REMARKS DISPLACE- JOINTS MENT ROTORUA New Zealand J. Brown & 1911 6” Oil suction Joints fitted early in Shipping Co., Co., Ltd., 12,000 tons 5” line. 1923. Installation London Clydebank Bilge water watched by “Lloyds” and “Board of Trade”. Downloaded from http://asmedigitalcollection.asme.org/MTS/proceedings-pdf/MTS2013/99403/28/2792536/mts2013-0304.pdf by guest on 30 September 2021 MOLDAVIA Peninsular and Cammell, 1922 8” Oil suction Joints fitted in 1925. Oriental Steam Laird & Co., 16,000 tons line. Navigation Co., Ltd., Ltd. London Birkenhead MALOJA Peninsular and Harland & 1923 2 ½” to Water for Joints fitted in 1923. Oriental Steam Wolff, Ltd., 20,000 tons 5” baths and Navigation Co., Belfast various. Ltd., London PEGU P. Henderson & Wm. Denny 1921 3” Wash Deck. Joints fitted in 1921. Co., Glasgow. & Bros., Ltd. 8,000 tons Dumbarton. SHIRVAN Baltic Trading Co., Sir W. G. 1926 2 ½” Wash Deck. Joints fitted in 1926. Ltd. Armstrong 8,500 tons Whitworth & Co., Ltd. Walker SHIRAK Baltic Trading Co., Sir W. G. 1926 2 ½” Wash Deck. Joints fitted in 1926. Ltd. Armstrong 8,500 tons Whitworth & Co., Ltd. Walker OTIRA Shaw Savill & Harland & 1919 4” Water. Joints fitted in 1923. Albion Co. Wolff, Ltd., 10,000 tons Belfast KEMENDINE P. Henderson & Wm. Denny 1924 1 ¾ “ to Wash Deck. Joints fitted in 1924. Co., Glasgow & Bros., Ltd. 8,000 tons 3 ½” Fresh and salt Dumbarton water supplies MOOLTAN Peninsular and Harland & 1923 3 ½” Water. Joints fitted in 1923. Oriental Steam Wolff, Ltd. 12,000 tons Navigation Co., Belfast Ltd., London MATOROA Messrs. Geo Harland & 1922 6” Oil. Joints fitted in 1926. Thompson & Co., Wolff, Ltd. 12,000 tons 7 Billitier Sq. Belfast London TAMOROA Harland & 1922 6” Oil. Joints fitted in 1926. Wolff, Ltd., 12,361 tons Belfast AMARAPOORA P. Henderson & Wm. Denny 1920 3” Wash Deck, Co., Glasgow. & Bros., Ltd., 8,000 tons Fresh and salt Dumbarton water supplies (LIGHTSHIP) Irish Lights Office, Henry Robb 1926 2 ½” to 4 Compressed ALBATROSS Dublin. Ltd., Leith. ½” Air. Wash Deck.

33 EARLY MARINE USERS OF GROUNDED PIPING WHEN BUILT AND SIZE OF VESSEL OWNERS BUILT BY USE REMARKS DISPLACE- JOINTS MENT BAVARIAN Ellerman Lines, Sunderland 1895 2½” Wash Deck Ltd., . Shipbuilding 3,000 tons Co. Sunderland Downloaded from http://asmedigitalcollection.asme.org/MTS/proceedings-pdf/MTS2013/99403/28/2792536/mts2013-0304.pdf by guest on 30 September 2021 NARKUNDA P. & O. Steam Harland & 1920 3½” Fuel oil and air Joints fitted in 1927. Navigation Co., Wolff, Ltd., 16,000 tibs 6” lines to tanks. London. Belfast (LIGHTSHIPS) Irish Lights Office, Henry Robb 1923 1½”, 2”, Compressed GUILLEMOT Dublin Ltd., Leith. 3”, 4½” air lines TERN/PETREL Irish Lights Office, Compressed KITTIWAKE Dublin air lines. BEAVERHILL Canadian Pacific Barclay Curle 1927 2” to 4½” Bilge and Steamships ltd., & Co., Ltd., 10,500 tons ballast suction London Glasgow lines. BEAVERFORD Canadian Pacific Barclay Curle 1927 2” to 4½” Bilge and Steamships ltd., & Co., Ltd., 10,500 tons ballast suction London Glasgow lines. BEAVERBURN Canadian Pacific Wm. Denny & 1927 2” to 4½” Bilge and Steamships ltd., Bros., Ltd., 10,500 tons ballast suction London Dumbarton lines. BEAVERDALE Canadian Pacific Sir W. G. 1927 2” to 5” Bilge and Steamships ltd., Armstrong 10,500 tons ballast suction London Whitworth & lines Co., Ltd. BEAVERBRAE Canadian Pacific Sir W. G. 1927 2” to 5” Bilge and Steamships ltd., Armstrong 10,500 tons ballast suction London Whitworth & lines Co., Ltd. HIGHLAND Nelson Lines, ltd. Harland & 1928 2” to 4” Fresh water MONARCH Wolff Ltd., 15,000 tons suction Belfast HIGHLAND Nelson Lines, Ltd. Harland & 1928 2” to 4” Fresh water Motor vessel under CHIEFTAIN Wolff Ltd., 15,000 tons suction construction. Belfast LADY NELSON Canadian Cammell Laird 1928 11/2” to Bilge, ballast Vessel under Government & Co., Ltd. 7,750 tons 5” and oil fuel construction. Merchant Marine, suction lines. London. DUKE OF London, Midland Wm. Denny & 1927 2” to 5” Wash Deck, LANCASTER and Scottish Bros., Ltd., 3,800 tons Bilge and Railway Dumbarton ballast lines. DUKE OF London, Midland Wm. Denny & 1928 2” to 5” Wash Deck. Vessel under ARGYLL and Scottish Bros., Ltd., 3,800 tons 5” Bilge and construction Railway Dumbarton ballast lines. DUKE OF London, Midland Wm. Denny & 1928 2” to 5” Discharge Fitted by North ROTHESAY and Scottish Bros. Ltd., 3,800 tons 13” piping Eastern Marine Railway. Dumbarton. Engineering Co., in 1926

34 EARLY MARINE USERS OF GROUNDED PIPEING WHEN BUILT AND SIZE OF VESSEL OWNERS BUILT BY USE REMARKS DISPLACE- JOINTS MENT Wilh. Wihelmsen, Deutsche 1928 8” Motor vessel under Werke, A G., 9,500 tons Kiel M. V. CINGA- Prince Line, Blythswood 1929 2”, 3”, Double Joints installed by Downloaded from http://asmedigitalcollection.asme.org/MTS/proceedings-pdf/MTS2013/99403/28/2792536/mts2013-0304.pdf by guest on 30 September 2021 LESE PRINCE London. Shipg. Co., 4”, 5” & bottom pump Munro & Miller Ltd., Glasgow. 6” arrangement. M. V. , Harland & 1929 1 ½”, 2” Cold fresh BRITANNIC Liverpool Wolff, ltd., & 2 ½” water mains. Belfast S.S. ARMA- Australind Steam Wm. Denny & 1929 3”, 3 ½” Bilge, ballast DALE Ship Co., London. Bros. & 4” and engine oil Dumbarton. fuel pipes. S.S. PACIFIC Furness Withy & A/S 1929 3”, 4” & Oil and water RANGER Co., London Burmeister & 5” lines to ballast Wain’s tanks. Maskinog Skibsbyggeri, Copenhagen S.S. Union S. S. Co., of Ardrossan 1929 2”, Oil fuel pipes WAIMARINO New Zealand Dockyard Co., 2 ½” 3” and water Ltd. & 4” pipes.

Table 1 – Early UK list of vessels using grooved joints

35 THE EARLY RECOGNIZED ADVANTAGES

The recognized advantages grooved pipe joints brought to shipbuilding were many, including:

• Compact and leak tight pipe joints. • Valuable working tolerance in pipe length • Valuable working tolerance in pipe angle at the joints

• Grooved pipe fittings used to avoid bends and sets Downloaded from http://asmedigitalcollection.asme.org/MTS/proceedings-pdf/MTS2013/99403/28/2792536/mts2013-0304.pdf by guest on 30 September 2021 • Simplified planning and fitting pipe work • Reduction in pipe template work • Reduction/ elimination of pipe strain and stress at each joint due to flexing in rough seas • Elimination of stuffing boxes and pipe offsets to accommodate pipe expansion and contraction • Space savings vs. flanged connections • Easy to pass pipe through lighten holes in the ships structure (no flanges on the end of the pipes) • Easy to install, only two bolts per joint, easy access to the bolts • No bolt torqueing, simply tighten “pad to pad” • Ease of removing a pipe section without disturbing to rest, union at every joint • Does not require highly skilled labor • Pipe easily grooved with hand tools or on adapted threading equipment or pipe lathes • Time savings, in planning, fabrication, and installation • Vibration and noise attenuation

COMMENTS OF SUPERINTENDENT ENGINEERS

WHAT EARLY USERS SAID

From the Superintendent Engineer of a well-known Shipping Company :-- “With reference to the joints fitted to the oil pipe lines .. “In all cases where these were applied, either too long or short lengths of piping, there has not been the slightest sign of failures, consequently no new ones have been fitted since the vessel was converted to oil burning and this, in spite of the fact that on a number of occasions the vessel has encountered very heavy weather, which caused considerable damage elsewhere.

“I may say that should any more conversions be contemplated, similar joints would unhesitatingly be employed as we have every confidence in their tightness and flexibility.”

From another Superintendent Engineer :-- “I am pleased to be able to confirm my previous report that the Victaulic joints have proved quite satisfactory during the five years the steamer has been in commission.”

36 US SHIPBUILDING

Subsequent to the introduction of grooved piping in the UK, the US started seeing grooved piping appear in 1926, first in the oil field and in natural gas, later in shipbuilding. The advantages recognized in the UK were also important in the US with 300 or more ships employing grooved joints up into the early phases of WWII. A partial listing of those vessels is included below in Table 2. Downloaded from http://asmedigitalcollection.asme.org/MTS/proceedings-pdf/MTS2013/99403/28/2792536/mts2013-0304.pdf by guest on 30 September 2021

President Jackson Wallace E. Pratt Esso Nashville President Monroe Esso Baytown Corsicana President Hayes Texas Sun Caddo President Garfield Rhode Island Calusa President Adams Louisiana Catawba President VanBuren Florida H. S. Falk Mormacpenn W. H. Berg J. P. Pulliam Mormacyork H. D. Collier Great Lakes Fleet Mormacland O.M. Bernuth William A. Irvin Mormaemail Tidewater Associated Nathan I. Miller Exchester Pennsylvania Sun John Hulst Exchequer Cimarron Ralph H. Watson Excelsior Seakay E. W. Pargny Examinister Esso New Orleans Alva C. Dinkey Delbrazil Ohio Henry C. Frick Delargentino M.E. Lombardi D. G. Kerr Delorleans Esso Augusta William J. Olcott Joseph Lykes America Sun Henry H. Rogers Zoella Lykes Esso Little Rock William B. Dickson Reuben Tipton Oklahoma George W. Perkins Fred Morris Esso Williamsburg James A. Farrell John Lykes Atlantic Sun William E. Corey Pochahontas Virginia J.H. McLean American Manufacturer Esso Richmond Cornell American Leader Esso Raleigh Thomas F. Cole American Builder U.S.S. Salamonie J. P. Morgan American Engineer Pan-Virginia B. M. Clemson American Packer Pan-Georgia John w. Gates Cape Alava Pan-Delaware Peter A. B. Widener Cape Flattery Pan-Carolina Mataasa Cape Cleare Pan-Pennsylvania William A. McGonagle G. Harrison Smith Mercury Richard Trimble Esso Bayonne Esso Baton rouge Isaac L. Ellwood Esso Bayway R.W. Gallagher Queen City Esso Houston Esso Baltimore E. C. Collins Esso Boston Esso Charleston George F. Baker Pan-New York Henry Phipps

37 Pan-Maryland Platte Taurus Pan-Rhode Island Esso Annapolis Wallace Markay Esso Albany Amasa Stone Neosho Mobilfuel Diamond Alkali Esso Trenton Mobilube Dow Chemical Esso Montpelier L. P. St. Clair Thunder Bay Quarries Esso Concord Victor H. Kelly

Table 2 - Partial listing of ships that utilized Grooved Joints in the USA Downloaded from http://asmedigitalcollection.asme.org/MTS/proceedings-pdf/MTS2013/99403/28/2792536/mts2013-0304.pdf by guest on 30 September 2021

EARLY GROOVED JOINT SHIPBOARD APPLICATIONS

• For air vent pipes to fuel oil tanks • For pipes in alleyways • Pipes passing through cabins • For fresh water and sanitary services • For wash deck and fire services • Compressed air services of all descriptions. e.g., on Diesel-engine ships, for charging purposes and filling starter bottles. • For torpedo air compressing engines, etc. • For hydraulic services of all kinds, e.g., telemeters, hydraulic steering gears. • For refrigeration services • On oil tankers for fuel oil filling • Great advantage in Duct Keels

EARLY APPROVALS

Sanctioned by U.S. Maritime Commission – Bureau of Marine Inspection and Navigation – American Bureau of Shipping – British Board of Trade – Lloyd’s Register of Shipping – Bureau Veritas – British Corporation.

WORLD WAR II

World War II saw even more use of grooved piping on shipboard applications. The following Figures 4 & 5 are from a 1944 Victaulic publication.

38 Downloaded from http://asmedigitalcollection.asme.org/MTS/proceedings-pdf/MTS2013/99403/28/2792536/mts2013-0304.pdf by guest on 30 September 2021

Figure 4 – From 1944 Victaulic Co. of America Catalog and Engineering Manual (Page 18)

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Figure 5 – From 1944 Victaulic Co. of America Catalog and Engineering Manual (Page 19)

Technical features of the flexible grooved pipe joint.

FLEXIBILITY

The coupling illustrated below is of the type known as “flexible” in that each coupling permits angular deflection of pipe lengths in any direction. In addition, each coupling automatically takes care of contraction and expansion of pipe lengths via the axial clearance between the “keys” and the width of the groove in each pipe end. See Figure 6. The coupling housings are bolted together and meet each other “metal to metal” or what is known as “pad to pad” fixing the diameter of the keys that engage the grooves at a diameter nominally slightly larger than the groove diameter. This results a small radial clearance between the keys and floor of the groove which helps facilitate the angular flexibility and a small amount of rotational movement capability. When fitting pipes from bulkhead to bulkhead, or from deck to deck, flexible couplings give a valuable “working tolerance” in both length and angle of the pipes. In ship operation, these same tolerances are no less valuable. They absorb and eliminate the potentially damaging strains and stresses imposed on rigidly connected, joints, and brackets by the natural “working” and movement of the hull.

40 Downloaded from http://asmedigitalcollection.asme.org/MTS/proceedings-pdf/MTS2013/99403/28/2792536/mts2013-0304.pdf by guest on 30 September 2021

Figure 6 – Grooved Pipe Joint, Flexible Type

POSITIVE LOCK OF PIPE LENGTHS

The coupling lock of pipe lengths is no guess-work affair. It is a positive engagement of metal housings with grooved pipe lengths. See Figure 7. This lock develops the full strength of the pipe wall with full circumferential engagement of the pipe ends. Pipes resist pull out or blow off under pressure or vacuum, - under vibration or movement due to this positive mechanical engagement.

Figure 7 – Grooved Pipe Joint Positive Engagement of Coupling Housings with Grooved End Pipe 41 SEALING

Grooved pipe joint gaskets (seals) provide a triple seal. First the gasket is stretched a modest amount to fit over the pipe ends. This “stretch” actully provides an intial sealing even without the coupling housings installed. Second the couplings housings are installed which compresses the gaskets radially tighter against the surface of the pipe. In this state, sealing has been enhanced by compression as the elastomic seal conforms tightly to the pipe surface,

sealing on typical pipe surfaces such as painted, varnished, bare, galvanized and the like and is Downloaded from http://asmedigitalcollection.asme.org/MTS/proceedings-pdf/MTS2013/99403/28/2792536/mts2013-0304.pdf by guest on 30 September 2021 leak tight against very low pressure gases and liquids. Third, the gasket shape responds to pressure or vacuum (negative pressure) in a manner further intensifying sealing force against the pipe surfaces, see Figure 8 below (pressure shown in top of figure, negative pressure at bottom). Given its ability to seal negative pressure, grooved piping is often used in “submerged” applications, such as within tanks.

Figure 8 – Grooved Pipe Joint, Gasket, Sealing Enhancement Under Pressure; Positive Pressure Top, Negative Pressure Bottom

SPACE, WEIGTH SAVINGS

Size and weight of joints used in ships’ piping is of unusual importance. Grooved pipe joint couplings are compact and require considerably less space than flanged joints. Grooved piping can be nested snugly against the bulkhead, against the overhead, in the bilges or among other pipe lines. An example comparison of the space saving, weight saving, (Figure 9) and number of bolts is as follows: A typical 4” coupling weighs 7 lbs., has two bolts; - 4” flanged joint weighs 32 lbs., has 8 bolts.

42

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Figure 9 – 4" (114,3mm) Grooved Joint Coupling vs. 4" ANSI Class 150 lb. Flange Weight Comparison

CONSTRUCTION SAVINGS

Every flexible coupling provided an easy-fitting flexible pipe end tolerance, - elimnated the tedius exactitude of rigid pipe work. Less skillled labor could do the job, - a small socket wrench was the only tool needed. Ordinary pipe was used with grooved ends instead of screwed thread or beveled end. Each coupling incorporated the features of a pipe union, - pipe sections or fittings could be removed without disturbing rest of system.

Exaggerated for clarify

Figure 10 – Grooved Pipe “Union” at Every Joint, Ease of Pipe Section Removal

SPACE SAVINGS

The grooved joint was radally smaller than the flanged joint. This means they could be positioned closer to bulkheads an decks than flanged joints saving valuable space. Also, each coupling being secured with two bolts in all sizes, arranged parallel with each other and tangentially with the pipe and being “track head” style with heavy hex nuts, meant easy access to the nuts for one wrench/ socket installation. The coupling could also be rotated around the

43 pipes ends prior to fully tighening the nuts to facilitate even easier access. Conversly flange bolts are arranged parallel with each other and parallel with the pipe, are heavy hex head on the bolt and nut requiring two wrench tightening/ sequential/ staged torquing, numbering 4, 8, 12 per flange and so on as pipe size increases, the closer to the bulkhead or deck, the more difficult the access to bolts and nuts. See Figure 11 below. Downloaded from http://asmedigitalcollection.asme.org/MTS/proceedings-pdf/MTS2013/99403/28/2792536/mts2013-0304.pdf by guest on 30 September 2021

Figure 11 – Grooved Pipe Joint, Space Savings and Easy Bolting Access (Type “B” Couplings) vs. Flanged

44 NOISE AND VIBRATION ATTENUATION

Excessive vibration and noise are to be two of the main challenges in the shipbuilding industry. Not only do they decrease the lifetime of the system but they are also key elements in the comfort of passengers and crew.

All piping systems have vibration which is generated by equipment. In addition, some Downloaded from http://asmedigitalcollection.asme.org/MTS/proceedings-pdf/MTS2013/99403/28/2792536/mts2013-0304.pdf by guest on 30 September 2021 system movement can be expected from pressure thrusts during operation, most noticeable during the startup and shutdown of equipment due to the use of resilient pipe hangers and supports, and equipment mountings. In recognition of this, the piping system must be made flexible enough to permit equipment movement, or thermal expansion/contraction without reducing the performance of vibration isolators, and to prevent potentially damaging stains and stresses at connections.

In mechanical rooms, pumps, chillers, fans and boilers frequently create noise and vibration which can be difficult to contain. For example, oscillatory forces can be generated due to the lack of balance of rotating components such as from pump vanes. This can be reduced by “field balancing”, however, this requires specialized equipment, which makes it difficult, expensive and impractical.

INDEPENDENT TESTS

Faced with the need to diminish noise and vibration from equipment connected to piping systems, designers have traditionally specified elastomeric flexible arch connectors. However, independent tests have demonstrated that flexible grooved joints are far more effective at reducing noise and vibration.

When the structure of a flexible grooved pipe joint is examined, it can be seen why it effectively reduces sound transmission. The resilient elastomeric gasket, contained inside the internal cavity of the coupling housing, creates a discontinuity similar to that of a flex connector. The elastomeric material from which the gasket is made also serves to absorb vibration. See Figure 12

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Exaggerated for clarify Figure 12

FIGURE 12: The flexibility of grooved piping joints reduces the transmission of stain and therefore stresses through a piping system, while an elastomeric gasket and coupling housing combine to dampen vibration.

The key distinctions of a flexible grooved pipe joint over a flex connector are inherent in the design of the coupling. Its unique construction enables the gasket to seal against the pipe, while the coupling housing provides both space for the elastomeric material to flex. Overall, the coupling works to create a permanent leak-tight seal with no need for additional end load restraint.

NUTECH Testing Corporation/SE Laboratories, Inc. in the USA applied a vertical acceleration to one end of a pipe assembly, measured the responses and compared the performance of flexible grooved joints to elastomeric flexible arch connectors. The results showed that flexible grooved joints displayed the best vibration isolation/attenuation characteristics (Figure 5).

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FIGURE 13: Percentage of additional decrease in sound provided by a series of three flexible grooved pipe joints.

For any given pipe diameter, vibration isolation increases as the number of flexible grooved joints increases (i.e. less vibration is transmitted with each additional joint). A typical arrangement is to place three flexible grooved joints close to the source of vibration. This can be achieved in a variety of ways (see Figure 14). The use of additional grooved joints - whether flexible or rigid - in the system will further reduce the transmission of vibration.

These test results substantiate the use of flexible grooved joints for pump or equipment connections, not only because of their superior attenuation characteristics, but also because of their ability to accommodate misalignments and reduce strains and stresses at pump or equipment connections.

47 Flexible Coupling

Rigid* Coupling

Flange

3

2 Downloaded from http://asmedigitalcollection.asme.org/MTS/proceedings-pdf/MTS2013/99403/28/2792536/mts2013-0304.pdf by guest on 30 September 2021

1

Pump or Equipment

Nipple or Reducer 3

1 2

1 2 3

FIGURE 14: Three possible ways to arrange grooved flexible

1 joints in a piping system to deliver proven and effective 2 vibration/sound attenuation. 3

48 Hot Work

Grooved piping reduces the need for hot work and the safety precautions associated with it. Fire watches, ventilation (see Figure 15 below), warning signs, fire extinguishers at the ready (see figure 16 below), rescue procedures and trip hazards are all reduced with grooved piping. Downloaded from http://asmedigitalcollection.asme.org/MTS/proceedings-pdf/MTS2013/99403/28/2792536/mts2013-0304.pdf by guest on 30 September 2021

Figure 15 - Hot Work (Welding) Ventilation

Figure 16 - Fire extinguisher readiness

Bulkhead/ wall penetrations

Grooved piping requires smaller diameter penetration holes through bulkheads and wall than does flanged piping and thus lighter reinforcement of these penetrations due the smaller hole sizes. See Figures 17 and 18 below.

49

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Figure 17 - Bulkhead/ wall penetrations with grooved piping.

Figure 18 - Grooved piping vs. flanged piping wall penetration reinforcement

GROOVED PIPING SPECIFICATIONS

The first grooved pipe specification was written by the US military during or just after WWII. It was MIL-C-10387 for grooved pipes and couplings and MIL-C-10388 for grooved pipe fittings. Next came AWWA-C606 issued in the late 1960s widely used today.

In the early 1990s ASTM F-1476 was issued covering grooved pipe joints for marine applications as well as other “Gasketed Mechanical Couplings” used in marine applications. Companion standard ASTM F-1548 was issued shortly thereafter covering fittings for use with “Gasketed Mechanical Couplings”. In the early 2000’s, ISO standards 15837 and 15838 were issued, their basis being the above ASTM standards respectively.

APPROVALS

The earliest approvals occurred in the UK in the 1920s.

Victaulic Couplings had the sanction of the American Bureau of Shipping, Board of Trade, Lloyd’s Register of Shipping, Bureau Veritas, British Corporation and various departments of the U. S. Government, subject to a few applications that had to be submitted for approval. The coupling was suitable for water, air, oil and gas, at temperatures up to 150° F, but not for steam.

50 Later more approvals, including some in the US.

Sanctioned by U. S. Maritime commission – Bureau of Marine Inspection and Navigation – American Bureau of Shipping – British Board of Trade – Lloyd’s Register of Shipping – Bureau Veritas – British Corporation.

Approvals today include:

• ABS – American Bureau of Shipping (USA) Downloaded from http://asmedigitalcollection.asme.org/MTS/proceedings-pdf/MTS2013/99403/28/2792536/mts2013-0304.pdf by guest on 30 September 2021 • BV – Bureau Veritas () • CCS – China Classification Society (China) • DNV – Det Norske Veritas (Norway) • GL – Germanischer Lloyd (Germany) • KR – Korean Register of Shipping (South Korea) • LR – Lloyds Register (United Kingdom) • RINA – Registro Italiano Navale (Italy)

Today, grooved piping couplings have US Coast Guard approval for many shipboard applications.

• Potable Cold and Hot Water • Machinery Sea Water Cooling-inboard of the sea valve • Hot and Chilled Water for Air Conditioning • Bilge and Ballast systems • Cargo oil systems • Fire main/Sprinkler/Foam Systems-outside of the engine room • Fuel/Lube Oil Systems-outside of machinery spaces • Domestic Sanitary Drains and Deck Scuppers • Compressed Air

SUMMARY:

Grooved Piping Systems have had a long history of successful application on board ships and continue to be employed globally. The advantages are many, including Technical, Economic, Serviceability and Reliability, among others. They continue to grow in preference over other pipe joining methods with more and more ship yards, marine engineers and vessel owners who recognize its unique advantages.

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