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Lloyds Register Technical Association

AN INTERPRETATION OF THE IMOGUIDELINES ON THE APPLICATION

OF PLASTIC PIPES ON SHIPS

by

D. J. Cox

Paper No. 7. Session 1993-94


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The author of this paper retains the right of subsequent

publication, subject to the sanction of the Committee of

Lloyds Register of Shipping. Any opinions expressed and

statements made in this paper and in the subsequent

discussions are those of the individual and not those of

Lloyds Register of Shipping.

Written contributions to the discussion of this paper are

invited from members of the Lloyds Register Technical

Association. To ensure inclusion in the discussion paper,

the contributions should be received by the Hon. Secretary

in London not later than the 6th September 1994.

Hon. Sec. R. A. Goodwin71 Fenchurch Street, London, EC3M 4BS


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AN INTERPRETATION OF THE IMO GUIDELINES ON THEAPPLICATION OF PLASTIC PIPES ON SHIPSby

D. J. Cox

TABLE OF CONTENTS

SYNOPSIS

1. INTRODUCTION1.1 LR Rules1.2 IMO Guidelines

2. DESCRIPTION2.1 General2.2 Properties2.3 GRP Pipe Construction

3. PRESENT APPROVAL OF PLASTICS PIPE ANDPIPING SYSTEMS

4. INTERPRETATION OF THE IMO GUIDELINES4.1 Introduction4.2 Material Design Properties and Performance

Criteria1.0 Requirements applicable to all piping

systems.1.1 General 1.2 Internal pressure1.3 External pressure1.4 Axial strength1.5 Temperature

1.6 Impact resistance1.7 Ageing1.8 Fatigue1.9 Erosion resistance1.10 Fluid absorption1.11 Material compatibility2.0 Requirements applicable to piping systems

depending on service and/or locations.2.1 Fire endurance2.2 Flame spread2.3 Smoke generation2.4 Toxicity2.5 Electrical conductivity2.6 Fire protection coatings

4.3 Material Approval and Quality Control duringManufacture

4.4 Installation4.4.1 Supports4.4.2 External loads4.4.3 Strength of connections4.4.4 Control during installation4.4.5 Testing after installation on board4.4.6 Penetrations of fire divisions4.4.7 Penetrations of watertight bulkheads and

decks

4.4.8 Methods of repair

5. FUTURE APPROVAL OF PLASTICS PIPE ANDPIPING SYSTEMS

6. SUMMARY

7. ACKNOWLEDGEMENTS

8. STANDARDS

APPENDIX ASolas References

APPENDIX BPipe Joining Methods

APPENDIX CDefects

APPENDIX DData Requirements

David Cox began his sea-going career as a Marine Engineer Cadet with the Royal Fleet Auxiliary. Heremained at sea, serving with various shipping companies, until 1978 when he joined the CEGB at DeptfordPower Station, becoming a Senior Authorised Operations Engineer. From 1980 to 1989 he worked at seawith P&O Shipping. During his sea going career he worked on a wide variety of ships including Passenger,Dry Cargo, Gas and Oil tankers. Mr.Cox joined Lloyd's Register in 1989 and is now a Senior Surveyorin Piping Systems Department. His work within that department has involved the General and TypeApproval of glass reinforced plastic pipes. At present he specialises in Liquefied Gas Carriers and haslectured on the subject, both in H.Q. and abroad.


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SYNOPSIS

The Maritime Safety Committee (MSC) of the InternationalMaritime Organization (IMO.), at its sixty first session inDecember 1992, approved The Guidelines for the Applicationof Plastic Pipes on Ships. These guidelines were issued asMSC/Circ.580 on 21st December 1992, and subsequently

adopted by the IMO Assembly at its eighteenth session inNovember 1993, and are now contained within AssemblyResolution A.753(18).

While the use of plastics pipes in shore based applicationshas expanded and is now well established, the use of plasticspipes on ships has, to date, been limited by fire safety aspects.In addressing this issue, the IMO Guidelines have opened thedoor to the wider application of plastics pipes on ships.

In order to implement many aspects of the IMO Guidelines,Administrations will need to make their own decisions as tothe testing and use of plastics piping. It is the intention of thispaper to assist Surveyors in the interpretation and implemen-tation of the IMO Guidelines with respect to the work ofLloyd's Register of Shipping (LR) by proposing a starting pointfor future discussion on the subject.


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1. INTRODUCTION

1.1 LR Rules

Lloyd's Register Rules detailing the acceptance of plasticspipes have existed since the introduction of the ProvisionalRules for Plastic Pipes in 1963. The use of plastics pipes isdealt with by the present Rules in Part 5, Chapter 12, Section5,

the text of which is being revised to take account of the IMOGuidelines. Until recently a common use of plastic pipes hasbeen in the ballast system of crude oil tankers, both for newconstructions and the replacement of steel pipe on existingships. (Figures 1&2)

1.2 IMO Guidelines

In November 1993 the IMO Assembly adopted TheGuidelines for the Application of Plastic Pipes on Ships. Theseguidelines, previously issued as MSC/Circ.580, are containedwithin Assembly Resolution A.753(18).

The Guidelines evolved from requests by variousGovernments for an interpretation of terms such as steel or

other equivalent material which appear in Solas 1974 and itsamendments (See Appendix A), with particular reference tothe use of plastics pipes on ships. The status of the Guidelinesis advisory. They cover the design, installation and testing ofplastic pipes, with or without reinforcement, in essential or nonessential systems. Within the Guidelines there is freedom topermit the development of Classification Rules, Internationaland National Standards, while allowing the development ofnew technology.

The Guidelines do not cover flexible pipes or couplings,although these will need to be considered by LR.

The Guidelines are detailed, reflecting the amount of workwhich has gone into their formulation. However, they cover awide subject and while comprehensive in many respects, suchas fire endurance testing requirements, they give only generalguidance in other areas, leaving it to the respectiveAdministrations to apply criteria, which will be acceptable tothem.

Figure 1 New Installation

(Reproduced courtesy of Ameron)

Figure 2Existing ship, replacement of steel pipe with G.R.P.

(Reproduced courtesy of Shell Seatex)


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2. DESCRIPTION

2.1 General

Before detailing the topics covered by the Guidelines it maybe useful to give a general description of plastics pipes and themeaning of some of the terms commonly encountered.

Plastics used for piping systems on board ships can be

divided into two basic resin groups, thermoplastics and ther-mosets.Thermoplastics soften on heating and harden on cooling.

The process is reversible and there is no chemical change to thematerial. The material can be worked eg. bending and welding.

Thermosets, once having set or cured can no longer besoftened or moulded by the application of heat. Curing is anirreversible reaction as it involves a chemical change to thecross linking, or polymerization.

Typically the plastics used for piping are composite mate-rials which consist of:

Resin System + Reinforcement + Additives

a) Resin System:Polyester This is a common resin which is dissolved in asolvent such as styrene to make it a liquid. In order to curethe resin a catalyst is added. This curing process gives offheat (Exothermic reaction). Polyester resins are cheap,have good physical properties, and can be easily modifiedto specific uses.Epoxy These resins are cured with the aid of hardeners.Again this hardening process gives of heat. Epoxy resins aretough, have high chemical resistance, and low shrinkage.Other systems such as vinylester and phenolic are alsoavailable.

b) Reinforcement:Carbon fibre Used as a filament winding within the resin

system or as an outer layer.Glass fibre Increases strength and reduces expansionand contraction.

c) Additives:Additives are used to modify the physical properties orcolour of the resin base. They can be organic or inorganic,fibrous or granular. Some examples of additives and theiruses are given below:

Mica Temperature resistance.Carbon Resists ultra violet degradation. Provideselectrical conductivity.Pigments Provides opaqueness and colour.

2.2 Properties.

The properties of a glass reinforced plastic (GRP) pipe will varyconsiderably depending on the choice of resins, hardeners,roving, roving form, winding angle of the roving and the glasscontent of the reinforcement. The physical properties of afinished pipe can therefore be altered as required and while thisis an advantage to the designer, it presents problems to thoseapproving a pipe for use on board ship. Pipes, which are madefrom the same materials and which have the same wall thick-ness, will not necessarily have the same strength. Therefore inaddition to prototype testing of a Manufacturers pipes, anexamination of the Quality Control System will be very impor-tant, to ensure repeatable properties in their product.

Figures 3, 4 and 5 give an idea of the form of typicalstress/strain curves for plastics and steel materials. In generalplastics have a lower ultimate strength and modulus of elastic-

ity than metals, with a lower limiting operating temperature.Despite this the processing of plastics is fairly easy, they havea low density and are not susceptible to corrosion. Weightsaving and lack of corrosion are the main reasons for the useof plastic pipes on board ships.

Figure 3Typical stress/strain curve, unreinforced plastic

Stress

Strain

Un-reiforced

Plastic

Stress

Strain

Reinfor

cedPl

astic

s

Stress

Strain

Steel

Figure 4Typical stress/strain curve, reinforced plastic

Figure 5Typical stress/strain curve, steel


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2.3 GRP Pipe Construction

For the majority of services on board ship reinforced ther-mosets will be used, usually GRP. The construction of a typicalGRP pipe is shown in figure 6.

GRP pipes may incorporate some, or all, of the followingfeatures in their construction.

a) Reinforcement:Glass filaments (8 to 14 microns diameter) are twistedtogether in bundles of about 200, to form a continuousglass strand. In turn up to 60 of these strands are bundledto form a continuous glass roving.These continuous glass rovings are used as reinforcement

in a GRP pipe (See figure 7). They have high strength anda modulus of elasticity many times greater than that of thePolyester resin. In a composite pipe therefore, the glassfibres carry a correspondingly higher stress, thus addingstrength to the pipe.Typical grades of glass used as reinforcements are E Glass,which is a general purpose glass with low alkali content,and C Glass which is a high silica alkaline glass used wherea greater degree of chemical resistance is required.The glass can be used in a variety of forms such as;

Uni-directional strandsBi- directional strand.Continuous filament matChopped strand mat

Uni-directional Woven (See figure 8)

b) Liners:These may consist of a thermoplastic resin inner layer,which is added to increase a pipes resistance to chemicalattack and wear. This layer may, or may not, be rein-forced.The proportions of glass and resin in a typical pipeincorporating a reinforced liner are as follows:

Pipe 70% Glass, 30% ResinLiner 10% Glass, 90% Resin

c) Conductive elements:These are used to increase the electrical conductivity ofthe pipe.This can be achieved by the use of:

Additives Incorporated into the resin mix, ie Carbon.Conductive filaments Carbon fibre.Coatings Incorporated into the design as an outeror inner layer.

d) Fire Resistance:An additional degree of fire resistance can be given to aGRP pipe by the inclusion of additives to the resin, or theuse of a special coating of intumescent fire resistant mate-rial.

Coating-Insulation/

Fire protection

Filament wound reinforcement and resin

Resin rich inner layer

Resin rich outer layer

Filament wound

reinforcement

Uni-Directional

Glass Roving

Chopped Strand mat Bi-Directional Roving

Continuous

Filament mat

Figure 6 GRP pipe construction

Figure 7 Filament wound reinforcement

Figure 8 Glass roving


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3. PRESENT APPROVAL OF PIPE ANDPIPING SYSTEMS.

As stated earlier, LRs requirements are given in Part 5,Chapter 12, Section 5.of the Rules. Additional guidance canbe found in other documents such as Plan Approval CircularES/CIRC/PSD/91/037 or Approval of Load Line Conditions

of Assignment Guidance Notes, Revision Number 2. To datethe approval procedure has been based on the limited accep-tance detailed in these documents.

Pipes intended to be used in non essential services, such assanitary and domestic systems need not have been of a typeapproved by LR. The Manufacturers documentation showingconstruction, physical properties and joining methods mayhowever have been submitted.

Pipes used in other systems, such as Cargo and Ballast linesare required to be approved and this would have involvedsubmission of the Manufacturers product information, anexamination of the manufacturing works, and evidence of test-ing on selected sizes of pipe. In addition to the testing requiredby LR it is normal for pipe Manufacturers to have carried outtheir own programme of testing before applying to LR forapproval, and details of these tests are usually supplied tosupport any application for approval. The amount of testingrequired by LR has been limited. This does not mean that thetest requirements were not sufficiently stringent. It should beremembered that the services in which plastics pipes have beenaccepted until now have been either non essential, or, as in thecase of ballast lines in ballast tanks, in locations which are phys-ically protected and where failure will not result in flooding ordanger to the ship.

The Approval system to date has proved satisfactory withvery few reported cases of pipe failure. It is now intended toextend acceptance to other services, and therefore factorsother than those of internal pressure and temperature, againstwhich plastic pipes have been examined in the past, should betaken into account. The suitability of any pipe must now bedemonstrated by subjecting it to the testing regime detailed inthe Guidelines.

4. INTERPRETATION OF THE IMOGUIDELINES

4.1 Part 1 Introduction.

Part 1 of the IMO Guidelines covers the Purpose, Scope,Philosophy and Definitions and needs no interpretation.

4.2 Part 2 Material Design Properties and PerformanceCriteria.

This part of the IMO Guidelines is divided into two sections.The first relates to the testing requirements which are applica-ble to all pipes whilst the second relates to those additionaltests which may be required depending on the service and/orlocation of the pipes.

1.0 Requirements applicable to all piping systems.

1.1 General.

This sub-section gives several general statements whichshould be considered. Paragraph 1.2 states, The specificationof the piping should be to a recognised standard acceptable tothe Administration.... There are several published standardscovering the manufacture and testing of plastic pipes. Thesestandards, however, are not specifically intended for pipeswhich are to be used on ships and while many of the standardsdetail test methods which can be used to assess the suitabilityof a plastic pipe, it will be necessary to establish minimumacceptance criteria from these tests for marine applications.

1.2 Internal Pressure.

The nominal internal pressure for a pipe is found by acomparison of the short term and long term hydrostaticstrength as follows;

PN = Pst/4 PN = Plt/2.5

PN = Nominal Internal Pressure.Pst = Short Term Hydraulic Test Failure Pressure.Plt = Long Term Hydraulic Test Failure Pressure.(100000 hrs.)

Figure 9 shows this diagrammatically, where the strengthdecreases over a period of 100000 hrs. The short term hydro-static test failure pressure is divided by a safety factor of 4, andthe long term hydrostatic test failure pressure by a safety factor

100

70

50

Time (Hours) 100 000

2528

InternalPressure

(Bar)

Figure 9 Internal pressure test curve


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of 2.5. The nominal internal pressure for a pipe being taken asthe lesser of these two values.

These long and short term hydrostatic failure pressures canbe found by a combination of prototype testing and calcula-tion. Due to the length of time stipulated for the long termtest it is expected that testing will be carried out to a suitablestandard, such as ASTM 2837 and ASTM D 1598. These stan-dards allow tests to be carried out over a shorter period of

time and the results extrapolated. It should be rememberedthat the nominal internal pressure may need to be adjusted totake account of results obtained from ageing tests, and afurther allowance will also have to be made where a high maxi-mum service temperature is envisaged.

While the Guidelines allow for a combination of testingand calculation, the proportion of testing is not stated and theselection of sizes for testing will therefore be a matter of judge-ment. For a small range of pipe sizes with similar constructionthe testing of a single size may be adequate. However, forlarger ranges, testing of pipes from the top, middle and bottomof the range may be the minimum required. This testing willof course help to verify the calculations used to cover theremaining sizes. It should be realised however that the

Manufacturer may change the winding angle of the roving forthe larger sizes in a range, and it will be necessary to take thisinto account when selecting the pipe sizes to be tested, toensure that pipes incorporating these changes in constructionmethod are covered.

1.3 External pressure.

The requirement that piping be subjected to an externalpressure test is included in the section applicable to all pipingsystems. However, paragraph 3.1 of the Guidelines states thatexternal pressure is to be taken into account for installationswhich may be subjected to vacuum conditions inside the pipeor a head of liquid outside the pipe. These conditions will not

apply to all pipes.It is anticipated that the nominal external pressure for each

pipe size will be determined by a combination of testing andcalculation. The sizes required to be tested may be decided inthe same way as those for internal pressure testing. The resultsfrom these tests again being used to verify calculations for theremaining sizes. After the collapse pressure is determined afactor of safety of 3 is applied.

PN ext = Pcol/3

PN ext Nominal External Pressure RatingPcol Collapse Pressure

When steel or copper piping is employed onboard ships theRule thickness is calculated using the material properties,together with the appropriate formula given in Part 5Chapter 12 of the Societys Rules. This ensures that any pipingused is suitable for the internal design pressure of the system.While the calculations do not specifically take into accountthe additional factors given in the Guidelines, these aspectsare not ignored. For some pipes, calculations carried out inaccordance with the Rules would indicate that a thin pipe wallis adequate. However, regardless of this calculated value,there is a minimum value for wall thickness, below which pipesare not accepted, and these values are given in Part 5, Chapter12, Table 12.2.4. This table for minimum wall thickness ensuresthat pipes are not only suitable for the internal working pres-sure, but have a robustness, adequate for shipboard use.Similarly, where plastic pipes are used on board ships, an addi-tional thickness may be required, over and above thatobtained from calculations.

Many plastic pipes used in shore based applications aresuitable for the internal working pressure but are so thin thatthey deform or sag under their own weight when notsupported. Such pipes would be perfectly adequate as sayunderground pipes, where additional support is given by thetrench infill, but may not have the robustness necessary foruse on board ships.

Plastic pipes intended for use in dry compartments and on

the open deck will not be subject to an external head of liquidin the same manner as pipes located inside tanks. They mayhowever be subjected to other forces such as wave action,transportation, personnel traffic, or to vacuum conditions.

It is therefore suggested that testing to determine the pipesresistance to deformation under external load be carried outirrespective of whether the pipe is subjected to an externalpressure due to liquid head when it is in service. Testing to arecognised standard such as ASTM D 2412, which involvesdeforming a sample of pipe between parallel plates to measurethe deflection under load, would give an indication of a pipesrobustness.

1.4 Axial strength.

As stated in the Guidelines, the sum of the longitudinalstresses due to pressure, weight and other dynamic andsustained loads should not exceed the allowable longitudinalstress. When determining the longitudinal stresses in a system,thermal expansion and contraction should also be taken intoaccount.

The requirements of this section can only be dealt withwhen full details of the pipe and piping system are known.While these matters could be dealt with during the PlanApproval stage, Plan Approval for Classification purposes isonly concerned with the appraisal of schematic piping plans.The only Rule requirement for a complete pipe stress analysisbeing that given in the Gas Ship Rules Chapter 5. This is

however only in respect of cargo piping subject to tempera-tures below -110c. It is therefore not considered necessary toappraise calculations of expected pipe stresses, other than forlow temperature gas carriers, or examine details of the pipefastenings and hangings with respect to axial strength. For LRto carry out a pipe stress analysis, or even verify a pipingsystem designers calculations on every system employingplastic piping would be time consuming, and could beexpected to add considerably to the fees already charged.Consequently it may be acceptable to simply confirm that theBuilder has taken these matters into account in his design.

When considering GRP pipes care should be taken toensure that the sum of the longitudinal stresses does notexceed half the hoop stress at the nominal internal pressure.

This is particularly important as, while filament windingangles commonly vary between 55 and 85, it is possible toproduce a reinforced plastic pipe with a 90 winding angle,that is, limited axial strength.

1.5 Temperature.

A reduction in the physical properties of plastics materialswhen subjected to an increase in temperature is to beexpected. Pipe Manufacturers will normally provide relevantinformation in the form of a graph or table. In order however,for acceptance to be given to any pipe, testing of the resinmaterial should be carried out to determine the heat distortiontemperature using ISO 75 Method A, or equivalent.This is a

simple test involving a rectangular test specimen positionedbetween two supports, loaded in the centre, and thensubjected to an increase in temperature. The minimum heatdistortion temperature of the resin, that is the temperature at


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which the rate of material softening rapidly increases, shouldnot be less than 80c. From the test results the maximum work-ing temperature (Max WT) can be determined as follows.

Max WT = Min. Heat Distortion Temp -20c

Degradation at high temperatures may also be increasedby other factors such as the presence of oxygen. At low

temperatures plastics pipes become less ductile, althoughthere is some evidence that it is possible for plastic pipes toretain acceptable physical properties down to -175c. Ingeneral however plastic pipes on ships are expected to be usedin systems down to about -40c.

Where plastics pipes are proposed for low temperatureservice the Manufacturer would be expected to submitevidence of the pipes suitability, and any testing supportingthe Manufacturer's claim should be witnessed.

Fluctuation in operating temperature can, in time, lead tocrazing of the pipe material.

1.6 Impact resistance.

Plastics pipes are vulnerable to impact damage and wheredamage of this nature is likely to occur, for example wherepipes are located in the vicinity of a stores crane, suitableprotection should be provided.

The impact resistance of a plastic pipe should be measuredusing a suitable standard such as ASTM D 2444. The valuesobtained from this testing will enable future comparisons tobe made, thus aiding the selection of pipes for specific loca-tions.

1.7 Ageing.

Ageing may affect the physical properties of plastics pipes.It is normal for Manufacturers to have carried out testing to

measure the effect of ageing on their pipes. Unfortunately,where tests have been performed by a Manufacturer, the test-ing has usually been carried out with respect to their mainmarket, that is land based installations. Testing may haveinvolved exposing samples to ultra violet (UV) radiation,burying them in the ground for extended periods or ageingsamples in an oven. The Guidelines, however, require testingto be carried out to show that the pipes will not degrade signif -icantly after exposure to, not only the effects of UV radiation,but also salt water, oil, grease, temperature and humidity.

It should be confirmed that the Manufacturer has consid-ered these aspects and that any testing carried out is relevantto the intended use and/or location of the pipes. Where testingindicates that the properties of a pipe may be adversely

affected, the Manufacturer should take steps to counter anyageing effects. For example, the tensile strength of a plasticpipe can be adversely affected by UV radiation, which maygive rise to embrittlement or crazing. This is due to the photonenergy at the UV wavelength causing a dissociation of thechemical bonds in the polymerized chains. The effect of UVradiation can however be reduced by covering the pipe witha coating or by adding UV stabilizers or opaque fillers, suchas carbon, to the pipe material.

1.8 Fatigue.

The effects of cyclic and fluctuating load are to be consid-ered by the designer. For example, plastic pipes may have alimited fatigue endurance when subjected to highfrequencies.This is due to localised temperature build upwhich can occur within the material, although below 100 Hzthis is not expected to be a problem.

While the evaluation of test specimens is mentioned in theGuidelines, the designer may also rely on previous experiencewith a similar material. No specific testing is required and itis considered that this matter can be left to the pipeManufacturer and system designer.

1.9 Erosion resistance.

Again, as with fatigue there are no specific test require-ments in the Guidelines. Until specific operating experienceis gained the Manufacturers advice should be sought in thesematters. Where erosion is considered to be a problem it willbe necessary to obtain the Manufacturers confirmation as tothe suitability of their pipes, or request suitable testing.

To counter the effects of erosion, the Manufacturer canchange the pipe materials, increase the wall thickness or adda special liner to the pipes.

1.10 Fluid absorption.

Most plastics materials will absorb liquids to some degree,although this is usually a slow process. Fluid absorption testing

is therefore to be carried out to an acceptable standard. It mustbe remembered that the testing should cover, not only the fluidbeing carried inside the pipe, but also any fluid through whichthe pipe passes or with which it may come into contact, forexample, where pipes are located inside a ballast tank.

It may be necessary to carry out testing on any internal orexternal pipe coatings. It should be borne in mind that coatingswhich are separately applied to the pipe for fire resistancepurposes may be destroyed, or their properties greatlyimpaired by the absorption of certain liquids.

In general, Polymers are insoluble in water but the addi-tives, fillers and stabilizers used in the pipe construction areoften soluble, Styrene being an example.

1.11 Material compatibility.

Whereas plastic materials in general have a good chemicalresistance to a wide range of substances, most plastics aresusceptible to damage by at least one group of chemicals. Thisis of special concern when considering plastics pipes for useon chemical tankers, where the list of chemical cargoes mayrun into hundreds, not forgetting the solvents or cleanerswhich may also be used on board. Damage such as embrittle-ment, crazing, softening, swelling or absorption of the productcould occur. Where relevant information is not available, suit-able testing should be requested.

Consideration should also be given to the compatibility ofany fire resistant coating used, not only with respect to the

liquids which it may come into contact with, but also with theeffects of paints which may be applied.

2.0 Requirements Applicable to Piping Systems Dependingon Service and/or Locations.

2.1 Fire Endurance.

The fire endurance aspects are probably the most compre-hensive of all the sections in the Guidelines. Plastic pipes andtheir fittings, which are used in piping systems essential forthe safety of a ship, are required to possess a minimum levelof fire endurance. There are three levels of fire endurance test-ing given in the Guidelines, Level 1 (L1), Level 2 (L2) and

Level 3 (L3).Level 1 is the most severe test. Pipes are required to with-stand the fire test, detailed in Appendix 1 of the Guidelines,for 60 minutes in a dry condition. The severity of the test is


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designed to ensure the integrity of the pipe is maintainedduring a full scale hydrocarbon fire. This level is not onlyapplied to essential services but also to systems where failureof the pipe would release flammable liquids into the fire. Thetime /temperature relationship is given in figure 10, where itis compared to the SOLAS fire test curve.

Level 2 requires a pipe to be tested using the same testprocedure as that given for level 1, but for a duration of only

30 minutes in a dry condition.This level is intended for pipesin essential services, where the integrity of the pipe is requiredto be maintained after a fire of short duration such that thesystem can be restored.

Level 3 is intended for water filled pipes, where theintegrity of the pipe is required to be maintained such thatthe system can be restored after a fire of short duration. Thetest procedure is given in the Guidelines, Appendix 2.

Level 1 and 2 testing is carried out on a dry pipe inside afurnace, while level 3 is an open test on a liquid full pipe. Thisdifference in the test method is necessary due to the dangerof a liquid full pipe bursting inside a hot furnace.

In all the above tests it should be noted that where a fireprotective coating is necessary for a pipe to achieve the

required level of fire endurance, the coating becomes an inte-gral part of the fire endurance rating of the pipe. Such coatingshave not previously been considered acceptable by LR andwhere fitted, their long term integrity will become a necessarysafety factor worthy of periodic survey.

Appendix 4 of The Guidelines lists the relative fireendurance requirements in the form of a matrix. This matrixcovers most piping systems, and takes into account both thepipe contents and its location. It can be seen from the matrixthat the fire endurance requirements for say a ballast line willchange from 0 when the pipe is situated inside a ballast tank,to L3 when the pipe passes into the pump room or machineryspace. In the matrix a 0 is used for those locations where plas-tic pipes are accepted but no fire endurance testing is

required.Throughout the matrix, footnotes have been added to

detail additional requirements covering specific situations.For example, footnote 1 states that where non metallic pipingis used, remotely controlled valves are to be provided at theships side and that these valves are to be controlled fromoutside the space. This is applicable to all sea water pipeswhere there is a risk of flooding should fire damage occur.

When using the matrix it may be helpful to note that it wasdeveloped with fire safety aspects in mind, and references tospaces, or connections between spaces, refer to the spacesbounded by fire division boundaries, and not necessarily indi-vidual compartments within these fire division boundaries.Furthermore, other than footnotes 7 and 10, no differentia-

tion is made between the various types of ships, passenger,dry cargo, tanker etc.The Level 1 fire test is a 1 hour test at temperatures up to

1100c, in the dry condition. At the time of writing this paperit is understood that no plastics pipe has yet withstood sucha test, with or without a fire protective coating.In fact unpro-tected plastics pipes can be expected to endure only 3 to 6minutes exposure to this test.

Both SOLAS and Part 5, Chapter 13, Section 2.1.3. ofthe Ship Rules state that materials sensitive to heat are notto be used in certain services. However, the Guidelinesprovide an internationally agreed fire endurance standardwhich will permit the use of these materials where they arecurrently prohibited. It is recognised that these standards

are severe, however, it is not unreasonable to require suchtesting in order that Administrations can be confident thatthe pipes will provide a minimum level of safety in a firesituation.

2.2 Flame Spread.

The flame spread characteristics of a plastics pipe shouldbe determined using the testing procedure given inResolution A653(16) Recommendation on the ImprovedFire Test Procedures for Surface Flammability of Bulkheads,Ceiling, and Deck Finish Materials, as modified in accor-

dance with Appendix 3 of the Guidelines. Because the testinggiven in resolution A 653(16) uses a flat test piece, Appendix3 of the Guidelines detail the modifications necessary toenable a pipe to be tested using the same test rig. The testrequirement relates to all pipes, except those within tanks,cofferdams, void spaces, pipe tunnels and ducts, where a fireis unlikely to occur. This approach differs from the flameretardant testing requirements for electrical cables, whichare applied to cables in all locations, as electrical cables canin themselves be the source of a fire.

2.3 Smoke Generation, and,2.4 Toxicity.

IMO has been concerned for many years about smokegeneration and the levels of toxicity given off from burningmaterial on ships, however, at present, there is no agreedtesting standard. Any testing procedure must be able to accu-rately measure the smoke or toxic products given off duringtests and be repeatable so that accurate comparisons can bemade between samples. Smoke and toxicity tests arecurrently being evaluated, although it may be some timebefore agreed test procedures and acceptance criteria aredeveloped. Until these matters are finalized toxicity andsmoke generation should still be considered when approvingpipe materials and fire protection coatings, as someAdministrations may wish to limit the use of plastic pipes inaccommodation, service and control spaces.

Any consideration will be based on the results of flamespread or non combustibility testing which may be carriedout by the Manufacturer, together with any experiencegained from the use of similar materials.

1200

1000

800

600

400

200

0

0 10 20 30 40 50 60

Time (minutes)

Temperature(C)

SOLAS

Guidelines Appendix 1

Figure 10 IMO and SOLAS fire test curves


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2.5 Electrical Conductivity.

Some liquids are non conductive and the flow of suchliquid through a pipe can generate electrostatic charges onthe surface of the pipe. This is not a problem for conductiveliquids or systems incorporating steel pipes as any electro-static charge is led to earth via the liquid or the steel pipewall and pipe brackets. Plastics materials however, are poor

conductors of electricity and an electrostatic charge canaccumulate in the pipe. Sudden discharge of this electro-static charge, in the form of sparks, can cause explosions inhazardous areas and damage to the inner or outer surfaceof a pipe, resulting in the outflow of pipe contents.

While LR presently recognizes the need for some pipesto be electrically conductive, such as those within the cargotanks of products tankers, the Guidelines now extend thisrequirement to any pipe in areas which may becomehazardous in a fault condition, regardless of the fluid beingcarried. This will now include all pipes within cargo tankson crude oil and product tankers, together with pipes inhazardous areas on deck and spaces adjacent to cargo tanks,where a dangerous atmosphere may be present.

Where it is necessary to have an electrically conductivepipe, testing will need to be carried out to verify that theresistance per unit length of pipe does not exceed 1x10 5

Ohms/m. There are two types of testing, for volume orsurface conductivity.

The test for volume conductivity involves measuring theelectrical resistance through a sample of plastic between twoembedded electrodes. The test gives good repeatableresults.

The test for surface conductivity measures the electricalresistance between electrodes which are placed on thesurface of a pipe. As this test is very sensitive to the surfaceconditions, repeatability is hard to achieve and this makescomparisons between tests difficult. It is however, the

surface conductivity which is important and hence this is thetesting which should be requested. Testing to ASTM F 927or ASTM D 257 could be accepted.

After installation on board, the resistance between anypoint in the piping installation and earth should be checkedand is not to exceed 1x106 Ohms. Any earthing straps usedare to be accessible for inspection.

2.6 Fire Protect ion Coatings.

Various methods have been proposed to protect plasticspipes in a fire situation.

A common method is to coat both pipe and fittings withan intumescent coating. These coatings consist of a combi-

nation of chemicals in an epoxy resin. The chemicals arechosen so that in a fire situation they will expand and char,forming an insulating barrier around the pipes. A disadvan-tage with this system is that while the expansion and charringis taking place, smoke and fumes are usually given off. Someof these fumes may be toxic and therefore any proposal touse such coatings inside machinery or accommodation areasshould be carefully considered.

Other coatings may consist of mineral fibre or ceramiclayers.

Where the fire endurance of a pipe is dependent on theprotective coating, the IMO rating, L1, L2, etc., is valid onlyfor the combination of pipe and coating that has been tested.

It should also be noted that plastics pipes are vulnerableto axial heat penetration from conventional metallic fittings,ie.valves, which if not insulated can act as very effective heatsinks in a fire. Adequate protection of those fittings for thefire test and in service is very important to the success of the

installation. Similarly metallic pipe supports, if allowed toget hot, can have a deleterious effect on the piping systemin a fire.

Modifying the pipe material may be beneficial in reduc-ing flame spread, smoke generation and toxicity.

4.3 Part 3 Material Approval and Quality Control During

Manufacture.Amendments are currently being made to LRs Rules to

take account of the Guidelines. Once published, the revisedRules will state LRs requirements for material approval andQuality Control (QC) during manufacture.

As already mentioned, the physical properties of acomposite pipe are dependent on many aspects such as thematerials used, type of reinforcement, angle of windings,cure time etc. It is therefore important that a Manufacturerhas a system of quality control which wil l ensure that all pipeproduction will possess identical properties to those of thepipes which have been tested.

It is expected that following any request for LR Approvalof plastic pipes the LR Surveyor will visit the Pipe

Manufacturers Works to examine the pipe productionmethod and witness the agreed tests, ensuring that:

All Materials used are in accordance with those givenin the approval documentation.

When alternative materials are used, the details of thesealternative materials have been submitted as part of theapproval documentation.

Adequate records are kept of the materials purchased,including date received. To ensure that materials areused within their expected shelf life.

Storage conditions are adequate, ie.temperature andhumidity.

Adequate testing and inspection is carried out on the

raw materials before use. The pipe manufacturing procedures, as submitted, are

being adhered to.(ie.Winding angle, curing time,temperature)

Procedures exist for rectification of faults should theybe found during testing or inspection.

The results of this testing and inspection are recorded. Completed pipes and fittings are labelled correctly and

adequately. Pipes are stored in a reasonable manner prior to ship-

ment of an order.

4.4 Part 4 Installation.

4.4.1 Supports.

As with any piping system the design of brackets and theirspacing is important. Plastics pipes, and PVC pipes in partic-ular, expand much more than steel pipes. This should not initself cause any problems in a system specifically designedfor plastics pipes. It is worth noting however that whereminor modifications, or replacement of steel pipes with plas-tics pipes, is undertaken on an existing ship, several factorswill need to be considered.

The support brackets used for steel pipes will probablynot be suitable for a plastics pipe, even if the pipe is of thesame outside diameter. The plastic pipe brackets should bedesigned to allow for the increased movement of the pipe

with temperature variations. Due to this increased move-ment, the brackets must not be over tightened, as this couldlead to pipe damage by crushing. Where movement isexpected between a pipe and bracket, saddles or a thin metal


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cladding can be fitted in way of the bracket strap to accom-modate any wear, without affecting the performance of thepipe.(Figure 11).

As plastics pipes are not rigidly clamped, provision mayneed to be made to take thrust loads and the weight of thepipes when they are mounted in the vertical position. Theseforces can be transmitted to the pipe bracket by means ofsaddles which are bonded to the pipe.(See figure 12).

Further, the span between supports may need to be shorterfor a plastics pipe than for a steel pipe. The Manufacturersdocumentation will usually give information as to the accept-able spacing. This should only be treated as a guide,particularly as such documentation is normally of a generalnature and applies to land based installations, which are notsubject to forces such as roll, pitch, heave or wave loading expe-rienced on a ship.

Any heavy items, such as valves or filter bodies, should beindependently supported to prevent excessive forces on theplastic pipe.

4.4.2 External Loads.

Temporary point loading may occur in places where personnelare likely to walk over the pipes or in stores handling areas.Where such locations are identified, suitable protection shouldbe provided. This is not a matter that can be dealt with at thePlan Approval stage and therefore are best dealt with by theon site Surveyor.

4.4.3 Strength of Connections.

There are various methods of joining plastics pipes, several ofwhich are shown in Appendix B, together with a brief expla-nation of each one. It should be noted that, irrespective of theproperties of the pipe and the testing carried out, the use ofplastic pipe may be limited by the joining method used. Forexample joints incorporating a single or double O-ring areregarded as slip joints similar to mechanical couplings, whetheror not a locking ring is employed.

4.4.3.1 Adhesives.

These are used for joining pipe to pipe or pipe to fittings (Seefigure 13). The adhesive normally consists of two parts, a resinand hardener, which are supplied in pre-measured quantities,ready to be mixed together just before use. The chemicals

should be stored under the correct conditions. They have alimited shelf life, and must be used before the Manufacturersexpiry date.

Each adhesive will vary depending on the manufacture andmake of pipe used and subsequently the choice of adhesive willbe very important. In fact the internal pressure rating of a GRPpiping system may be reduced by as much as 50% by changingfrom an epoxy to a vinylester adhesive. It will, therefore, benecessary to know the properties of any adhesive which is tobe used.

4.4.3.2 Couplings.

Where flanged joints are used, the flanges may be pre formedonto the end of the pipe length in the factory. In this case theglass filament roving is drawn up around a former to producethe flange. It would be expected that any faults at this stage

will be picked up by the QC inspections during manufacture.Alternatively, molded flanges can be attached to the pipes onsite (See figure 14). It is usually necessary to machine the outersurface of a GRP pipe in way of the flange. The pre formedflange is then slipped over this prepared end and fixed in posi-tion with adhesive. The machining of the pipe end can becarried out using a special tool supplied by the Manufacturerand, when correctly used, this should produce a good outersurface concentric with the pipe bore. The length and profileof the cut is important if problems are to be avoided at a laterstage(See figure 15). If the hub of the flange is not positionedhard against the back of the cut, a gap will be left. While this

Bracket

Saddle

Bracket Saddle

Figure 12 Pipe thrust saddle

Figure 13 Adhesive Bonded Joint (Spigot and Socket)(Reproduced courtesy of Ameron)

Figure 11 Pipe bracket


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13

gap may subsequently be filled with resin, the resultant thin-ning of the pipe wall in this area leads to a reduction in strength.This has been known to lead to cracking. Incorrect machiningof the pipe could also lead to local overheating which may causedegradation and softening of the resin. To overcome theseproblem, it is important that the pipe Manufacturers instruc-tions are followed with respect to the use of cutting fluids, feedrates and the correct cutting tools. It is possible for the

Manufacturer to supply the pipe sections with pre machinedends, but of course this may add to the installation costs and itis a decision for the Shipyard whether pipes are purchased inthis condition.

Couplings of the mechanical type provide a convenientmethod of joining pipes, however, these couplings vary indesign depending on whether they are intended to join plasticto plastic, or plastic to steel. Usually the coupling bolt tighten-ing torque is less for a plastic pipe, therefore it is importantthat the correct type of coupling is used, and the Manufacturersfitting instructions followed.

Where pipes are required to be electrically conductive, theelectrical continuity must be maintained across the pipeconnections by the use of bonding straps, conductive adhesiveor conductive O rings.

While corrosion is not expected to affect plastics piping, thecouplings may contain metal parts which in some cases aresubject to increased corrosion and should therefore be care-fully inspected at regular intervals.

It should be noted that screwed couplings are available butare not considered acceptable for use on board ships.

4.4.4 Control During Installation.

The Guidelines detail the qualification procedure necessaryfor each person required to carry out the joint bonding. Thisis a self certification process, the testing being carried out bythe Manufacturer or the Yard who will maintain a record show-ing the bonding procedure, performance qualification, datesand results of testing for each person. These records should beavailable for inspection.

For essential services, each qualified person should makeone test joint, representative of each type to be used. The test

joint should then be hydrostatically tested to an internal pres-sure of 4 times design pressure for 1 hour. During the test thereshould be no separation of the joint or leakage. This testingshould be witnessed and carried out at the place of construc-tion, where conditions and equipment may differ from thosewhere the bonders qualification procedure was carried out.

There should also be a system of Quality Control checks toensure repeatability of the joining method and it must beensured that conditions, such as humidity, temperature andcleanliness, are suitable for the joining process, that is, withinthe limits set by the Manufacturer.

4.4.5 Testing After Installation On Board.

a) Pressure testing:The Guidelines require that pressure testing be carriedout after installation on board, that is:

1.5 x WP for essential services.Leak Test for other services.

From Classification aspects, pressure testing shouldgenerally be in accordance with Part 5, Chapter 12, Section7 of the Rules. The requirements of Pt.5, Ch.12.7.2.2. relat-ing to pipes which have been assembled on board will alsoapply to plastic pipe systems where bonding has beencarried out on board.After any pressure testing the test pipe should be exam-ined for evidence of damage such as cracking or crazing

of the surfaces.

b) Conductivity:The resistance to earth should be measured whereconductive piping is required to be fitted. Readings are tobe greater than 1x106 Ohms from any point on the pipeto earth.It is expected that in some systems a mixture of conductiveand non conductive piping will be used, for example,ballast lines passing from a dangerous to safe zone. It willtherefore be necessary to ensure that the correct pipe hasbeen used in each location, and the resistance to earthverified where necessary.

c) Non Destructive Examination (NDE):The Manufacturers QC System should ensure that thepipes produced are free from defects. However, wherepipes are joined on site by adhesive bonding methods, non

,

Figure 14 Cemented flange joint

Figure 15 Adhesive bonded flange


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destructive testing may be required. The examination ofGRP pipes has previously been addressed in the discus-sion document on LRTA paper Developments inUltrasonic NDE by J.W.Hamilton. The situation remainsas stated in this document, that while various techniquessuch as radiography, eddy currents and acoustic emissionhave been tried, there are as yet no practical proceduresfor thick section GRP pipe inspection. Examination will

therefore be limited to pressure testing and visual inspec-tion. A light can sometimes be used to aid the visualinspection. This is a simple procedure whereby a brightlight is placed inside a GRP pipe. The light is visible whenviewed from outside the pipe and should show up anyirregularities in the roving, air bubbles, or trapped foreignparticles. Clearly this test will not work on pipes whichincorporate opaque fillers or colouring.

d) Defects:The inspection of pipes is detailed in several Codes andNational Standards. Several of the more common defectsare given in Appendix C.

4.4.6 Penetration of Fire Divisions.

The Guidelines require that fire resistance is not impairedwhere penetrations are made for the passage of plastic pipesthrough A or B class divisions. They also state that anyarrangements should be tested in accordance withRecommendations for fire test procedures for A B andF bulkheads (Resolution A.517(13)), as amended.

Where it is necessary to lead plastic pipes through fire divi-sions the arrangements should be submitted for approval.

4.4.7 Penetration of Watertight Bulkheads and Decks.

Any penetrations of watertight bulkheads or decks should

maintain the watertight integrity and strength of the deck orbulkhead. Further, where the deck or bulkhead is also a firedivision, a metallic shut off valve should be fitted at the deckor bulkhead, if destruction of the plastic pipe will cause inflowof liquids from tanks. This valve is to be operable from abovethe freeboard deck. Details of any such penetrations should besubmitted for approval.

4.4.8 Methods of Repair.

The Guidelines state that pipe material should be capable oftemporary repair by the ships staff, and that the necessarymaterials and tools be kept on board. Currently LR Rules donot cover repairs to piping systems.

Damage caused by falling objects, weld splatter etc. is likelyto occur to plastic pipes, either in service or during fitting outstages of newbuilding. This possibility should be anticipatedand the pipes adequately protected. Where damage doesoccur, the damaged section should ideally be removed andreplaced with material of the same type. Patch type repairsare possible, but in each case a full 360 wrap around of thelaminate, with sufficient overlap of the damaged area, shouldbe made.

Full details of any repair procedure, indicating the materi-als used, curing temperatures etc, should be submitted forconsideration. In most cases it will be necessary for a prototypetest to be carried out to verify that the strength of the pipe willbe maintained. Such repairs may be considered permanentsubject to periodic examination at suitable intervals, and fulldetails of any repairs should be retained on board.

As it is the intention of the Guidelines that the repair ofdamaged piping can be carried out at any time, it is anticipated

that a limited amount of repair material will be carried onboard, for example:

a) Lengths of pipe. It is unusual for a ship to carry sparelengths of pipe of every size on board. It is not howeverenvisaged that much, if any, spare plastic piping will becarried. The emphasis being on temporary, in service,repairs of the Patch type, until such time as a permanent

repair, or the replacement of damaged pipe sections canbe carried out (See Figure 16).

b) Flanges/elbows/tees etc. As for lengths of straight pipe,

it is not envisaged that many, if any, of these fittings willbe carried on board.

c) Couplings Couplings of the mechanical type may becarried, as it can be expected that they will be used to facil-itate removal of pipe sections for maintenance purposes,and the replacement of damaged pipe sections withoutresorting to laminating joints. It is important to check that,where a repair has been carried out, the correct couplinghas been used and that the Manufacturers fitting instruc-tions have been followed.

d) Resins and Hardeners. For most of the repairs expectedto be carried out on board it will be necessary to use aresin and a hardener. These are commonly supplied inseparate tins which contain the correct quantities, ready

for mixing. Under normal circumstances these will not beused and as such may be stored for prolonged periods. TheManufacturers recommendations must therefore befollowed with regard to the conditions under which thesechemicals are stored and used. Factors such as low temper-atures or high humidity could impair the curing andadhesion of any repair, seriously affecting the propertiesof any repaired pipe.

e) Rovings. For the purposes of repair, these are usuallymade from woven glass strands. The storage life andconditions are not as critical as for resins and hardeners,however, care should still be taken to prevent physicaldamage to the roving or impregnation with water or oilproducts before use.

f) Fire Coatings. Where a section of pipe has been given afire protective coating, this will need to be removed inorder to expose a section of pipe requiring repair. It willtherefore be necessary to ensure that any fire protection

Figure 16 Temporary repair saddle


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coating is reinstated satisfactorily after repairs. Some fireprotection coatings are sprayed on, while other coatingsmay consist of a separate barrier, such as fire resistantlagging. In the case of spray coatings the same precautionsapply as for resins and hardeners, that is, limited shelf lifeand correct conditions for application.

g) Electrical bonding straps. Spare bonding straps of eachtype used on board may not be carried. Consequently,

where conductive pipes are required to be fitted it will beimportant to check that any bonding straps are undam-aged and have been correctly replaced. A check of theelectrical resistance to earth should be carried out afterany repairs.

h) Availability of spares. Considering the low density ofplastics materials, and therefore their low weight, it shouldbe possible to airfreight most items needed to carry out arepair. While it is anticipated that the worldwide availabil-ity will improve, with the increased use of plastics pipes,the present speed of delivery worldwide means thereshould be no major delays in acquiring spares fromManufacturers.After a ship has been delivered and has left the Building

Yard it may be necessary for repairs to be carried out usingpipes or fittings manufactured by a company different tothose originally fitted. In each case the pipe used shouldbe of an approved type and suitable for the intendedservice. If the joining method incorporates an adhesivejoint, details of the pipe materials and adhesives shouldbe examined to ensure compatibility.

i) Information held on board. It is expected that the mate-rial Manufacturers instructions will be followed when anyrepair is undertaken, and instructions detailing the proce-dures to be followed must be available on board.

5. FUTURE APPROVAL OF PLASTICS PIPEAND PIPING SYSTEMS.(INCORPORATING THE GUIDELINES)

Having decided on an interpretation of the Guidelines, it willbe necessary to produce general requirements which can beused to assess the suitability of any plastics pipe requiring

approval in future.It is anticipated that the information to be submitted willbe similar to LRs present Data submission requirements, (seeAppendix D).

Once the details of the pipe material and constructionmethod have been examined, a test programme will be drawnup covering the testing detailed in the Guidelines.

It will also be necessary for the place of manufacture to beinspected with respect to the Quality Control System, to ensurethe system of pipe production is such that repeatable propertiescan be achieved for the pipes.

As with our present approval procedure the pipeManufacturer should indicate those services in which the pipesare intended to be used. A statement of the intended uses isneeded in order that a suitable test programme can beproduced. The Manufacturer, however, may be unaware of thefull range of services in which plastic pipes will now be permit-ted on board ships. In this case it will be necessary to brieflyexamine the product before suggesting a list of services inwhich the pipe may be accepted. While some of the requiredtesting may already have been carried out, it is expected thatin most cases additional testing will be specified. TheManufacturer will also need to consider whether it is intendedto use the pipes in locations where a level of fire endurance isrequired, and if so, to which fire endurance level the pipe is tobe tested. Careful consideration of these matters at an earlystage of any application for approval will help to preventunnecessary and expensive testing, while ensuring that thepipes are approved for all the services intended.

For many of the tests, required by the Guidelines, there areno test methods given, or set values at which pipes will beconsidered to have failed. It will therefore often be left to theManufacturer to decide on the test method to be used. Theresults obtained from this testing should be recorded so thatfuture comparisons can be made between different pipes, orwhere a Manufacturer changes the materials used. Eventuallythis accumulated data may be used to set acceptance criteria.

Tables 1 and 2 list the test requirements detailed in theGuidelines, indicating those tests which should be witnessedby the Surveyor, together with suggested testing standards, andthe minimum sample range where appropriate.

Table 1 Requirements covering all piping systems

Test Standard Sizes

Internal pressure IMO Guidelines Top, Middle,Short term (w) Bottom (of range)Long term (w)

External pressure (w) IMO Guidelines Top, Middle,Bottom (of range) (i)

Load deformation ASTM D 2412 Top, Middle,Bottom (of range)

Axial strength Installation design

Temperature ISO 75 Method A One sample oflimitations each type of resin

Impact resistance ASTM D 2444 One sample of each type ofconstruction (ii)

Ageing Manufacturer's Each type ofstandard construction (ii)

Fatigue Manufacturer's One sample of standard or service each type ofexperience construction (i)

Errosion resistance Installation design (i ) (ii)

Fluid absorption Manufacturer's (i) (ii)standard

Material compatibility Manufacturer's (i) (ii)

standard(w) Test to be witnessed(i) If applicable(ii) to include any coatings

Table 2 Additional requirements depending on serviceand/or location

Test Standard Sizes

Fire endurance Guidelines Each size and typeLevel 1, 2 or 3 (w) Appendix 1 and 2 of construction (i)

Flame spread (w) Guidelines Each size and typeAppendix 3 of construction (i)

Smoke generation To be considered (i)

Toxity To be considered (i)

Electrical ASTM F 927 or Each size and typeconductivity (w) ASTM D 257 of construction (i)

(w) Test to be witnessed(i) If applicable

(ii) to include any coatings


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6. SUMMARY

The Guidelines are intended to aid Administrations whenmaking decisions on the use of plastics piping. They have beenwritten in such a way that Administrations can, in many cases,apply their own acceptance criteria as they see fit.

Experience is yet to be gained from the use of plastic pipes

in many of the services listed in the Guidelines and it can beexpected that requirements will change as their use increases.In order, however, to deal with the expected increase in the

use of plastic pipes following the introduction of theGuidelines, it is now necessary for LR to re-assess the previousacceptance criteria and extend the scope of services for whichplastic pipes could be accepted.

7. ACKNOWLEDGEMENTS

The author would like to express sincere thanks to all thosewithin Engineering Services Group who offered advice andassistance, in particular Mr.R.Moore for his contribution.

The author would also like to thank Capt. W.Roselaar,Ameron, Mr.G.Grimm, Shell Seatex and Mr.D.van der Kamp,

Wavin for their valuable advice and supply of material used inthe preparation of this paper.


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8. STANDARDS

API 15LR Specification for Low Pressure FiberglassLine Pipe.

API 15HR Specification for High Pressure FiberglassLine Pipe.

ASTM B 117 Salt Spray (Fog) Testing.

ASTM D 257 D-C Resistance or Conductance ofInsulating Materials.ASTM D 570 Test for Water Absorption.ASTM D 648 Test for Deflection Temperature Under

Flexural Load.ASTM D 883-86b Standard Definitions of Terms Relating to

Plastics.ASTM D 1598 Time to Failure of Plastic Pipe Under

Constant Internal Pressure.ASTM D 1599 Test for Short Term Rupture Strength of

Pipe and Fittings.ASTM D 2412 Test for External Loading Properties of

RTRP. Parallel Plate Loading.ASTM D 2444 Impact Resistance of Thermoplastic Pipe

and Fittings by Means of a Tup (fallingweight).

ASTM D 2563 Classification Visual Defects in RTRP.ASTM D 2583 Hardness Test Barcol.ASTM D 2837 Obtaining Hydrostatic Design Basis for

Thermoplastic Pipe Materials.ASTM D 2924 Test for External Pressure Resistance of

RTRP.ASTM D 2996 Specification for RTRP.ASTM F 927 Electrical Conductivity.ISO 75 Method A


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APPENDIX ASOLAS REFERENCES

Chapter II-1 Reg.17.9.4.steel or other equivalent material(discharges led through theshell plating)

Chapter II-1 Reg.21.1.3.steel or other suitable material (all bilge pipes in or undercoal bunkers or fuel storage tanks or in boiler or machineryspaces)

Chapter II-2 Reg.5.3.3.4steel or other equivalent heat resisting material to the satis-faction of the Administration (piping systems essential for therelease of systems)

Chapter II-2 Reg.15.2.8.steel or other approved material (oil fuel pipes)

Chapter II-2 Reg.18.2.1.materials approved by the Administration having regard tothe temperature such divisions are required to withstand(pipes penetrating A or B class division)

Chapter II-2 Reg.18.2.2.a material approved by the Administration having regard tothe fire risk (the pipes conveying oil or combustible liquidsthrough accommodation and service spaces)

Chapter II-2 Reg.18.2.3.materials readily rendered ineffective by heat (overboardscuppers, sanitary discharges, and other outlets which are closeto the water line and where the failure of the material in theevent of fire would give rise to danger of flooding)

Chapter II-2 Reg.18.2.4.material readily rendered ineffective by heat (cargo ventpiping and cargo piping of tanks dedicated for carrying crudeoil and petroleum products having a flashpoint notexceeding 60c


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APPENDIX BJOINTS AND JOINING METHODS

General.

a) The Manufacturer's recommendations should befollowed carefully.

b) Joints must not reduce the rating of the pipe system.c) Joint strength should be checked at the Surveyors discre-tion.

d) Pipes must be adequately supported, while allowing forexpansion and contraction.

e) Heavy valves and fittings must be adequately supported.f) Where electrically conductive pipe systems are required,

the continuity of a conductive path across the joints is tobe ensured ie.conductive adhesive , conductive O ringsor external bonding straps may be required.

1. Adhesive Bonded Joints.(Figure A1)This is a rigid joint (flange or socket type), made using atwo-component adhesives.The following assembly procedures are critical: preparation of the pipe, dryness and cleanliness,

mixing proportions of adhesive, application of adhesive, bringing together of the pipes, curing time and curing temperature.

Problems: these joints are difficult to control in situ and are

practically impossible to remake in the event of leak-age,

pipe wall thickness may be reduced too much in wayof the joint,

internal voids, resin rich areas, eccentric machining of the pipe ends, inadequate support and/or system design allowing

excessive stress to be transmitted to the rigid gluedjoint,

the pipes are not normally dismountable unlessflanges are incorporated in the system.

2. Rubber Seal Joint(Spigot and Socket).(Figure A2)A non-rigid joint using an Oring seal which can be

supplied ready for Dry assembly. accommodates limited angular misalignment, accommodates limited expansion or contraction.

Problems: centre to centre alignment of joint is critical, depth of engagement of spigot into socket is critical, anchoring of pipe is essential.

3. Rubber Seal Lock Joint.(Figure A3)A non rigid joint using an Oring seal with the additionof a locking key to prevent pull out of the joint. Thisjoint is little used in marine installations, but widely usedashore in buried systems where anchor fixing points arenot readily available.

anchoring of the pipes is not critical.

4. Double O Ring Joint.(Figure A4)A non rigid joint using two O ring seals, similar to therubber seal joint (Spigot and Socket), the outer O ringis used to keep the inner seal surfaces clean. limited angular misalignment can be accommodated

which is normally sufficient for shipboard applica-tions,

anchoring of the pipes is essential.

, , ,

,

,

,

,

, , ,

, , , ,

Figure A1 Adhesive bonded jointFigure A3 Rubber seal lock joint single 'O' ring

Figure A4 Rubber seal lock joint double 'O' ring

Figure A2 Rubber seal joint single 'O' ring


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5. Mechanical Couplings.(Figure A5)A non rigid joint which can be used on plain ended pipefor the connection of GRP, steel or cast iron pipes. Suitablevariants of the coupling can be used for connection toflanged valve, bulkhead spool piece etc. pipe outside diameter is critical, angular alignment is critical, anchoring of pipe is essential.

6. Shell type flange connection.(Figure A6)While this is not the Manufacturer's production joint, it isincluded to show one repair method which should be usedon installations where pipes have been damaged. Thedamaged sections are cut off and GRP collars adhesivelybonded to the pipe ends. The pipes are then drawntogether with the use of steel backing rings and throughbolts. This method can also be used on plain ended pipes.

Although it has some of the drawbacks associated withadhesive bonded joints, it is fully dismountable and thecollars can be attached in controlled workshop conditions.

, ,

, , , ,

GRP 'collars' on pipe endsSteel backing rings

Figure A5 Mechanical coupling Figure A6 Shell type flange connection


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APPENDIX CDEFECTS

Typical defects, together with suggested maximum acceptable level

Defect Description Inside Pipe Outside Pipe

Blister Bubbles of air trapped None 6mm dia. x 1.5mm

beneath the laminate high (i)surface

Chip Small pieces broken None 6mm long with nooff due to impact damage to thedamage glass laminate

Crack Separation or splitting None Noneof the laminate

Scratch Small surface grooves Acceptable provided no damage toglass laminate

Crazing Fine cracks at or under None Slight, if no damagesurface to the laminates (ii)

Pin hole Porous surface 3mm dia. x 0.5mm deep (i)

Exposed or At the surface or a None Noneunwetted glass cut edgefibres

Foreign particles Trapped particles None None (i)

(i) Blisters, pin holes and surface foreign particles may be ground and filled provided there isno damage to the laminates and the physical properties of the pipe are not affected.

(ii) Crazing may occur after impact damage or pressure testing.

All repair procedures should be agreed on a case by case basis prior to commencementof work.


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APPENDIX DDATA REQUIREMENTS

EXTRACT FROM PLAN APPROVAL CIRCULARES/CIRC/PSD/91/037

4. Data to be submitted for approval

Where G.R.P. piping, which has not previously beenapproved, is proposed for installation on board ships, thefollowing data should be submitted for consideration.4.1 The pipe manufacturers name and address.4.2 The trade name and reference numbers or designa-

tion specific to the piping.4.3 The resin type, polyester or epoxide, together with

the manufacturers name and address and full tradename and reference number.

4.4 The catalyst and accelerator types employed in thecase of reinforced polyester resin pipes, or harden-ers, where epoxide resins are employed, also theirmanufacturers name and address and the full tradename and reference number for these additives.

4.5 A statement of all reinforcements employed,together with manufacturers trade names and refer-ence numbers. Where the reference number doesnot identify the mass per unit area in the case ofchopped strand mats or woven products or the texnumber of a roving used in a filament windingprocess, these are to be detailed.

4.6 Full information regarding the type of gel-coat orthermoplastic liner employed during construction,as appropriate.

4.7 A full statement of the manufacturing process, iden-

tifying the order in which the reinforcements areplaced, the mass of reinforcement employed in thesuccessive layers during construction and theresin/reinforcement ratios in the individual layers ofthe construction.

4.8 The cure and post cure temperatures and timesemployed.

4.9 Details of the quality control methods and testsconducted, both during manufacture and on thefinished products.

4.10 The dimensions and tolerances permitted of thefinished products.

4.11 A full statement of tests conducted on the subjectpiping to evaluate its bursting pressure, weepingpressure, resistance of flexural fatigue, deflectionunder load, resistance to build up of static electricalcharges and resistance to fire.

4.12 Recommendations for installation, including joiningof pipe sections to each other and to metallic piping,also the distance between supports.

lloyds gre.pdf

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