EN 13121-3:2016

GRP tanks and vessels for use above ground - Part 3: Design and workmanship

This European Standard gives requirements for the design, fabrication, inspection, testing and verification of GRP tanks and vessels with or without thermoplastics lining for storage or processing of fluids, factory made or site built, non-pressurized or pressurized up to 10 bar, for use above ground. Further requirements are presented in normative Annex G.
The terms vessels and tanks as used in this part of EN 13121 include branches up to the point of connection to pipe work or other equipment by bolting and supports, brackets or other attachments bonded directly to the shell.
This part of EN 13121 covers vessels and tanks subject to temperatures between - 40 °C and 120 °C.
Excluded from this part of EN 13121 are:
-   tanks and vessels for the transport of fluids;
-   underground storage tanks;
-   spherical vessels;
-   vessels and tanks of irregular shape;
-   tanks and vessels with double containment where the double wall is considered structural;
-   tanks and vessels which are subject to the risk of explosion, or failure of which may cause an emission of radioactivity;
-   specification for fibre reinforced cisterns of one piece and sectional construction for the storage, above ground, of cold water (see EN 13280).

Oberirdische GFK-Tanks und -Behälter - Teil 3: Auslegung und Herstellung

Dieser Teil der EN 13121 legt Anforderungen für Auslegung, Fertigung, Prüfung sowie Nachweis für oberirdische GFK-Tanks und -Behälter mit oder ohne thermoplastische(r) Auskleidung fest, die im Werk oder auf der Baustelle gefertigt und drucklos oder bis zu 10 bar druckbeaufschlagt sind und zur Lagerung oder Verarbeitung von Fluiden dienen.
Die Begriffe Behälter und Tank im Sinne dieses Teils der EN 13121 umfassen auch Abzweige bis zur Verbindung mit Rohrleitungen oder anderen Anlagenteilen, wie Verschraubungen, Stützen, Halterungen oder anderen Anbauteilen, die unmittelbar mit der Schale verbunden sind. Dieser Teil der EN 13121 verlangt neben den festgelegten Anforderungen auch die vollständige Dokumentation der in Abschnitt 5 angegebenen Unterlagen.
Dieser Teil der EN 13121 gilt für Behälter und Tanks, die Temperaturen zwischen −40 °C und 120 °C ausgesetzt sind.
Es ist möglich, dass Tanks und Behälter aufgrund der künftigen Entwicklungen auf dem Gebiet der Harz-technologie für Betriebstemperaturen über 120 °C geeignet sein werden. Sollte diese Situation eintreten und ein Hersteller sich diese Entwicklungen zu Nutze machen wollen, behalten alle anderen Anforderungen der Norm weiterhin ihre Gültigkeit, die Auslegung der betreffenden Tanks und Behälter muss jedoch ausschließ-lich nach dem in 7.9.2 angegebenen Verfahren erfolgen.
Dieser Teil der EN 13121 gilt nicht für:
 Tanks und Behälter für den Transport von Fluiden;
 unterirdische Lagertanks;
 kugelförmige Behälter;
 Behälter und Tanks mit unregelmäßiger Form;
 Tanks und Behälter mit doppelter Sicherheitshülle;
 Tanks und Behälter, die bei Explosion oder Undichtheit die Emission radioaktiver Strahlungen zur Folge haben können;
 einteilige und mehrteilige oberirdische faserverstärkte Tanks für die Lagerung von Kaltwasser (siehe EN 13280:2001).

Réservoirs et récipients en PRV pour applications hors sol - Partie 3 : Conception et fabrication

La présente Norme Européenne spécifie les exigences concernant la conception, la fabrication, le contrôle, les essais et la vérification des réservoirs et des récipients en PRV avec ou sans revêtement en thermoplastique, pour applications hors sol, destinés au stockage ou au traitement de fluides, fabriqués en atelier ou construits sur site, non soumis à la pression ou soumis à une pression allant jusqu’à 10 bar. Des exigences supplémentaires sont données dans l’Annexe G normative.
Les termes récipients et réservoirs, tels qu’ils sont utilisés dans la présente partie de l’EN 13121, incluent les tubulures jusqu’au point de raccordement à la tuyauterie ou à un autre équipement par boulonnage et les supports, consoles ou autres attaches fixés directement sur l’enveloppe.
La présente partie de l’EN 13121 couvre les réservoirs et les récipients soumis à des températures comprises entre - 40 °C et + 120 °C.
Sont exclus de la présente partie de l’EN 13121 :
-   les réservoirs et récipients destinés au transport des fluides ;
-   les réservoirs de stockage enterrés ;
-   les récipients sphériques ;
-   les récipients et réservoirs de forme irrégulière ;
-   les réservoirs et récipients à double enveloppe dans lesquels la double paroi est considérée comme étant structurelle ;
-   les réservoirs et récipients qui sont soumis à un risque d’explosion ou dont la défaillance risque de causer une émission radioactive ;
-   la spécification relative aux citernes renforcées par des fibres, construites en une pièce ou à partir de plusieurs éléments, destinées au stockage de l’eau froide, hors sol (voir l’EN 13280).

Nadzemni rezervoarji in posode iz umetnih mas, ojačanih s steklenimi vlakni - 3. del: Konstruiranje in izdelava

Ta del standarda EN 13121 podaja zahteve za projektiranje, izdelavo, pregled, preskušanje in preverjanje nadzemnih rezervoarjev in posod iz umetnih mas, ojačanih s steklenimi vlakni, z ali brez termoplastične obloge, za skladiščenje ali obdelavo tekočin, ki so industrijsko pripravljeni ali zgrajeni na mestu uporabe ter niso pod tlakom ali so pod največjim tlakom 10 barov.
Izraza posode in rezervoarji, kot se uporabljata v tem delu standarda EN 13121, vključujeta razvejitve do točke priključitve na cevno napeljavo ali drugo opremo z vijaki in oporniki, nosilci ali drugimi priključki, ki so vezani neposredno na ogrodje. Poleg dokončnih zahtev ta del standarda EN 13121 zahteva tudi, da so postavke v 5. točki v celoti dokumentirane.
Ta del standarda EN 13121 zajema posode in rezervoarje, ki so izpostavljeni temperaturam od –40 °C do 120 °C.
Tehnologija na področju smole bo v prihodnje morda napredovala do te mere, da bo omogočala uporabo rezervoarjev in posod pri temperaturah nad 120 °C. Če se bo to zgodilo in se takrat proizvajalec odloči, da bo takšen napredek izkoristil, vse druge zahteve iz tega standarda ostanejo v veljavi, takšni rezervoarji in posode pa morajo biti zasnovani samo v skladu z metodo napredne zasnove iz točke 7.9.2.
Ta del standarda EN 13121 ne zajema:
– rezervoarjev in posod za transport tekočin;
– podzemnih rezervoarjev;
– sferičnih posod;
– posod in rezervoarjev nepravilne oblike;
– rezervoarjev in posod z ojačano hrambo;
– rezervoarjev in posod, pri katerih obstaja nevarnost eksplozije ali okvare, ki lahko povzroči radioaktivne emisije;
– specifikacije za z vlakni ojačene cisterne v enem kosu in sestavljive cisterne za nadzemno skladiščenje hladne vode (glej standard EN 13280:2001).

General Information

• Status: Published
• Publication Date: 12-Apr-2016
• Withdrawal Date: 30-Oct-2016
• ICS: 23.020.10 - Stationary containers and tanks
• Technical Committee: CEN/TC 210 - GRP tanks and vessels
• Drafting Committee: CEN/TC 210 - GRP tanks and vessels
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 13-Apr-2016
• Due Date: 25-Feb-2016
• Completion Date: 13-Apr-2016
• Directive: 2014/68/EU - Directive 2014/68/EU of the European Parliament and of the Council of 15 May 2014 on the harmonisation of the laws of the Member States relating to the making available on the market of pressure equipment
• Directive: 97/23/EC - Directive 97/23/EC of the European Parliament and of the Council of 29 May 1997 on the approximation of the laws of the Member States concerning pressure equipment
• Mandate: M/071 - Mandate to CEN for standardization in the field of Pressure equipment
• Ref Project: SIST EN 13121-3:2016 - GRP tanks and vessels for use above ground - Part 3: Design and workmanship

Relations

• Replaces: EN 13121-3:2008+A1:2010/AC:2011 - GRP tanks and vessels for use above ground - Part 3: Design and workmanship
• Effective Date: 20-Apr-2016
• Replaces: EN 13121-3:2008+A1:2010 - GRP tanks and vessels for use above ground - Part 3: Design and workmanship
• Effective Date: 27-Feb-2013
• Revised: FprEN 13121-3 - GRP tanks and vessels for use above ground - Part 3: Design and workmanship
• Effective Date: 18-Jan-2023

Overview - EN 13121-3:2016 (GRP tanks and vessels, Part 3: Design and workmanship)

EN 13121-3:2016 is the European standard that sets design, fabrication, inspection, testing and verification requirements for glass‑fibre reinforced plastic (GRP) tanks and vessels for use above ground. It covers factory‑made and site‑built tanks and vessels (with or without thermoplastics linings) for storage or processing of fluids, non‑pressurized up to and including pressures of 10 bar, and operating temperatures between −40 °C and 120 °C. The standard also includes branches, supports and attachments bonded directly to the shell. Additional mandatory requirements appear in Normative Annex G.

Excluded are transport tanks, underground tanks, spherical or highly irregular vessels, double‑wall structural containment, and vessels exposed to explosion or radioactive release risks.

Key technical topics and requirements

• Scope and documentation - information to be supplied, manufacturer documentation and final records.
• Materials and linings - requirements for GRP laminates, chemical protective barriers, thermoplastic and resin‑based linings, flammability and electrical resistivity.
• Mechanical properties - laminate construction, thickness, inter‑laminar shear strength, peel and pull‑off strength; selection of allowable design factors.
• Design strain and loadings - limit design strains, laminate loadings and methods to determine mechanical values (with and without test data).
• Structural design methods - verification by the partial factor method, load combinations, and design calculations.
• Component and shell design - detailed treatment of cylindrical shells, conical shells, dished ends, flat bottoms, skirts, stiffening rings, and buckling criteria.
• Joints, openings and connections - circumferential seams, branch connections, pads, nozzles, prevention of peel failures and pull‑out loads.
• Testing and inspection - factory and site testing, inspection procedures and verification requirements.

Practical applications and users

Who uses EN 13121‑3:

• Design engineers and structural engineers specifying GRP tanks and vessels
• Manufacturers and fabricators responsible for workmanship, laminating and lining
• Quality inspectors and notified bodies performing testing, inspection and certification
• Plant owners and operators procuring above‑ground storage and process vessels for chemicals, wastewater, process fluids and compatible liquids

Typical applications:

• Above‑ground chemical storage and processing tanks
• Corrosion‑resistant process vessels with thermoplastic linings
• Site‑built or factory‑made GRP containment for industrial plants and water treatment

Related standards

• This part is one element of the EN 13121 series for GRP tanks and vessels.
• For one‑piece or sectional FR cisterns for cold water storage see EN 13280 (referenced in the scope).
• See Normative Annex G in EN 13121‑3 for further mandatory requirements.

Keywords: GRP tanks, GRP vessels, EN 13121‑3, design and workmanship, thermoplastics lining, laminate thickness, mechanical properties, above ground storage, tank inspection, partial factor method.

Standards Content (Sample)

SLOVENSKI STANDARD
01-junij-2016
1DGRPHãþD
SIST EN 13121-3:2008+A1:2010
SIST EN 13121-3:2008+A1:2010/AC:2011
1DG]HPQLUH]HUYRDUMLLQSRVRGHL]XPHWQLKPDVRMDþDQLKVVWHNOHQLPLYODNQL
GHO.RQVWUXLUDQMHLQL]GHODYD
GRP tanks and vessels for use above ground - Part 3: Design and workmanship
Oberirdische GFK-Tanks und -Behälter - Teil 3: Auslegung und Herstellung
Réservoirs et récipients en PRV pour applications hors sol - Partie 3 : Conception et
fabrication
Ta slovenski standard je istoveten z: EN 13121-3:2016
ICS:
23.020.10 1HSUHPLþQHSRVRGHLQ Stationary containers and
UH]HUYRDUML tanks
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 13121-3
EUROPEAN STANDARD
NORME EUROPÉENNE
April 2016
EUROPÄISCHE NORM
ICS 23.020.10 Supersedes EN 13121-3:2008+A1:2010
English Version
GRP tanks and vessels for use above ground - Part 3:
Design and workmanship
Réservoirs et récipients en PRV pour applications hors Oberirdische GFK-Tanks und -Behälter - Teil 3:
sol - Partie 3 : Conception et fabrication Auslegung und Herstellung
This European Standard was approved by CEN on 10 January 2016.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2016 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 13121-3:2016 E
worldwide for CEN national Members.

Contents Page
European foreword . 8
Introduction . 9
1 Scope . 10
2 Normative references . 10
3 Terms and definitions . 12
4 Symbols and abbreviations . 13
5 Information and requirements to be supplied and documented. 16
5.1 General . 16
5.2 Information to be obtained by the manufacturer . 16
5.3 Information to be prepared by the manufacturer . 17
5.4 Final documentation . 18
6 Material . 18
6.1 General . 18
6.2 Chemical protective barrier . 18
6.2.1 General . 18
6.2.2 Thermoplastics linings . 18
6.2.3 Resin based linings . 18
6.3 Flammability . 18
6.4 Electrical resistivity . 19
7 Mechanical properties . 19
7.1 General . 19
7.2 Heat deflection temperature . 19
7.3 Laminate construction . 19
7.4 Laminate thickness . 21
7.5 Laminate properties . 21
7.6 Inter-laminar shear strength . 21
7.6.1 Laminate . 21
7.6.2 Thermoplastics linings . 21
7.7 Peel strength of laminates . 22
7.8 Pull-off strength of laminates and thermoplastic liner . 22
7.9 Selection of physical properties of materials and allowable design factors . 22
7.9.1 General . 22
7.9.2 Basic design . 22
7.9.3 Advanced design . 23
7.9.4 Design factors . 24
7.9.5 Overall design factors K and F . 24
8 Determination of design strain and loadings . 27
8.1 General . 27
8.2 Limit design strains . 28
8.2.1 General . 28
8.2.2 Limit resin strain ε . 28
ar
8.2.3 Limit strain for laminate or lamina ε . 28
lim
8.2.4 Limit test strain ε . 29
test
8.3 Limit design laminate loadings . 29
8.4 Determination of the mechanical values from laminates . 29
8.4.1 General . 29
8.4.2 Calculation of laminate values without experimental test data . 29
8.4.3 Laminate with experimental data . 30
8.5 Laminate thickness . 30
9 Design . 30
9.1 Introduction. 30
9.2 Determination of external loads . 31
9.2.1 Snow loads . 31
9.2.2 Wind loads . 31
9.2.3 Seismic loads . 32
9.2.4 Insulation loads . 33
9.2.5 Loads resulting from connections . 33
9.2.6 Agitation . 34
9.2.7 Pressure due to inadequate venting . 34
9.2.8 Personnel loading . 34
9.2.9 Internal stresses in vessels and tanks due temperatures . 34
9.3 Verification by the partial factor method . 34
9.3.1 General . 34
9.3.2 Dimensioning by using (A⋅γ)-factored loads . 40
9.4 Drawings and design calculations . 41
9.5 Design details . 41
9.5.1 Design temperature TS . 41
9.5.2 Pressure . 41
10 Design analysis . 42
10.1 Symbols and units . 42
10.2 Vertical vessels or tanks, cylinders under loads (t < 0,01∙D) . 44
10.2.1 Circumferential loadings . 44
10.2.2 Combined axial loading . 45
10.3 Cylindrical shells subject to compressive loadings — critical buckling criteria . 46
10.3.1 General . 46
10.3.2 Critical axial buckling load . 46
10.3.3 Critical circumferential buckling pressure . 47
10.3.4 Combined axial and radial compressive loadings . 48
10.3.5 Critical buckling pressure for cylindrical shell stiffened with external or internal rings . 49
10.4 Conical shells . 50
10.4.1 General requirements . 50
10.4.2 Shallow conical ends . 52
10.4.3 Conical ends subject to internal pressure . 52
10.4.4 Conical ends subject to external pressure . 54
10.4.5 Shell conical covers . 56
10.5 Dished end . 57
10.5.1 General requirements . 57
10.5.2 Dished ends subject to internal pressure . 58
10.5.3 Stability for dished ends subject to external pressure . 59
10.6 Design of flat bottoms and skirts for vertical tanks and vessels . 60
10.6.1 Definitions . 60
10.6.2 Fully supported, flat bottom tanks . 60
10.6.3 Vessels with flat bases subjected to pressure . 67
10.6.4 Dished bottom and conical bottom configurations . 67
10.7 Circumferential seams for cylindrical joints . 77
10.7.1 General . 77
10.7.2 Construction without thermoplastics liner . 79
10.7.3 Construction with thermoplastics liner . 79
10.8 Openings, branches and compensating laminate . 79
10.8.1 General . 79
10.8.2 Symbols . 80
10.8.3 Compensation requirements for openings . 80
10.8.4 Pull out load from nozzles . 87
10.8.5 Prevention of failure in peel . 87
10.8.6 Pad connections . 87
10.8.7 Screwed connections . 89
10.8.8 Access and inspecting openings . 89
10.8.9 Gusset on branches . 89
10.9 Flat Panels or Blind flanges. 89
10.9.1 General . 89
10.9.2 Symbols . 90
10.9.3 Circular panels . 90
10.10 Horizontal tanks and vessels . 93
10.10.1 Types of supports . 93
10.10.2 Symbols . 95
10.10.3 Unit loads of the cylindrical shell . 96
10.10.4 Unit loads on saddle position . 103
10.10.5 Unit loads for horizontal loads at the vessel . 109
10.11 Large diameter pipes and pipe fittings . 110
10.11.1 General . 110
10.11.2 Joints . 111
10.11.3 Elbows . 112
10.11.4 Large cut-outs and Tees . 112
11 Bolted flange connections . 115
11.1 General . 115
11.2 Full face flanges design . 121
11.2.1 General . 121
11.2.2 Symbols . 122
11.2.3 Pipe loads on flanges . 124
11.2.4 Gasket load and bolt torque. 124
11.2.5 Summary of loads . 125
11.2.6 Total bending moment . 125
11.2.7 Flange design. 125
11.2.8 Flange slope . 127
11.3 Stub flange design with backing ring . 133
11.3.1 General . 133
11.3.2 Loads, bending moment and design for backing ring made of steel or GRP . 134
11.3.3 Stub flange loadings . 135
11.3.4 Stub shear interface design. 135
11.3.5 Stub end or flange design . 135
11.3.6 Seating stress . 136
11.4 Butt and strap jointed flanges at vessels or tanks . 138
12 Supports for vessels and tanks . 138
12.1 General . 138
12.2 Supports and mountings for tanks and vessels . 139
12.2.1 General considerations for supports . 139
12.2.2 Supports for vertical vessels . 139
13 Seismic loading . 145
14 Design calculation for tank and vessel anchorage . 145
14.1 General . 145
14.2 Design for uplift. 145
14.3 Design for anchor bolts. 145
15 Structures and fittings . 149
15.1 General . 149
15.2 Internal structures and fittings . 149
15.3 External structures and fittings. 149
15.4 Lifting devices . 149
16 Local load analysis . 154
17 Quality Control. 154
17.1 General . 154
17.2 Works requirements . 154
17.2.1 General . 154
17.2.2 Raw materials storage . 154
17.2.3 Manufacturing area . 154
17.2.4 Conditions for laminating . 154
17.3 Documentation to be prepared by the manufacturer . 155
17.3.1 Technical documentation . 155
17.3.2 Records and documentation requirements for raw materials . 155
17.3.3 Manufacturing documentation requirements . 156
17.3.4 Quality control documentation requirements . 156
17.4 Manufacture. 161
17.4.1 General . 161
17.4.2 Fabrication of thermoplastics liners . 162
17.4.3 Fabrication of laminates . 162
17.4.4 Imperfections in laminates . 163
17.4.5 Curing . 163
17.5 Inspection and testing after completion of fabrication . 163
17.5.1 Visual and dimensional inspection . 163
17.5.2 Physical test to be carried out . 164
17.5.3 Coupon testing . 164
17.6 Experimental Design Verification Method for pressure vessel . 165
17.6.1 General . 165
17.6.2 Manufacture of the prototype vessel . 165
17.6.3 Tests to be applied to prototype vessels . 166
18 Marking . 166
Annex A (informative) Product testing for serial or batch production process . 168
A.1 Initial type testing (ITT) . 168
A.2 Testing of samples . 168
A.2.1 General . 168
A.2.2 Batch release tests (BRT) . 168
A.2.3 Process control tests . 169
A.3 Inspection and test records . 170
A.3.1 General . 170
A.3.2 Marking . 170
A.3.3 Delivery, installation, maintenance . 170
Annex B (informative) Derivation of laminate properties from laminate properties . 171
B.1 General . 171
B.2 Lamina/laminate thickness . 171
B.3 Laminate modulus . 172
B.4 Determination of laminate flexural stiffness . 173
B.5 Determination of laminate strains from load resultants . 173
Annex C (normative) Pressure and leak testing . 175
C.1 General . 175
C.2 Open top tanks . 175
C.3 Static head test of closed tanks and vessels . 176
C.3.1 Contents having a specific gravity up to 1,0 . 176
C.3.2 Contents having a specific gravity greater than 1,0 . 176
C.4 Hydraulic pressure test . 176
C.4.1 Test done in the working attitude . 176
C.4.2 Tests done in other than the working attitudes . 176
C.4.3 Pneumatic testing . 177
C.4.4 Vacuum test . 177
Annex D (normative) Methods of tests . 178
D.1 General . 178
D.1.1 Tests . 178
D.1.2 Accuracy of test equipment. 178
D.2 Loss on ignition . 179
D.3 Tensile strength of thermoplastics welds . 179
D.4 Bend test for thermoplastics welds . 179
D.4.1 Introduction . 179
D.4.2 Test arrangement . 179
D.4.3 Test pieces . 180
D.4.4 Method of test . 180
D.4.5 Requirements from flexural test . 180
D.4.6 Test report . 180
D.5 Ultimate tensile unit strength of laminates . 181
D.5.1 Test pieces and procedure . 181
D.5.2 Simple laminates . 181
D.5.3 Combined laminates . 181
D.6 Unit tensile modulus of laminates . 182
D.7 Inter laminar shear strength of laminates . 184
D.7.1 Form of test specimen . 184
D.7.2 Number of test specimens . 184
D.7.3 Procedure . 184
D.7.4 Results . 184
D.7.5 Report . 184
D.8 Lap shear strength of bond between thermoplastics lining and laminate or between
laminates . 185
D.8.1 Form of the test specimen . 185
D.8.2 Number of test specimens . 185
D.8.3 Procedure . 185
D.8.4 Report . 186
D.9 Peel strength of bond between laminate layers . 186
D.9.1 Form of the specimen . 186
D.9.2 Number of specimens . 186
D.9.3 Procedure . 187
D.9.4 Report . 187
D.10 Flexural short-term creep test (flexural modulus E and E test) . 189
1h 24h
D.10.1 General . 189
D.10.2 Definitions . 189
D.10.3 Test device . 189
D.10.4 Test pieces . 190
D.10.5 Procedure . 190
D.10.6 Calculation . 190
D.11 Barcol hardness . 191
D.12 Determination of electrical resistivity . 191
D.13 Glass transition temperature by DSC of cured resin . 191
D.14 Spark testing of thermoplastics welds . 191
D.14.1 General . 191
D.14.2 Apparatus . 192
D.14.3 Procedure . 192
D.15 Long term flexural creep test . 192
D.15.1 General . 192
D.15.2 Definitions . 192
D.15.3 Test device .
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