Couplers, spigot pins and baseplates for use in falsework and scaffolds - Part 2: Special couplers - Requirements and test procedures

prEN 74-2 specifies for half couplers, reduction couplers for right angle and swivel
couplers, and sleeve couplers with shear suds:
- Materials
- design requirements
- strength classes with different structural parameters including nominal values
for resistances and stiffness which a coupler has to achieve
- test procedures
- assessment
- recommendations for on-going production control
for use principally in falsework and scaffolds. Each coupler is able to be fixed at least to 48.3 mm diameter steel or aluminium tube.
For testing, screw couplers are tightened with a torque of 50 Nm and wedge couplers are tightened with a 500 g hammer until the jarring blow.

Kupplungen, Zentrierbolzen und Fußplatten für Arbeitsgerüste und Traggerüste - Spezialkupplungen - Teil 2: Anforderungen und Prüfverfahren

EN 74-2 legt
   Werkstoffe;
   Baukonstruktive Anforderungen;
   festgelegte Werte für Widerstände und Steifigkeiten, die eine Kupplung bei der Prüfung erreichen muss;
   Versuchsdurchführung und Beurteilung
für die folgenden Spezialkupplungen fest:
   Halbkupplungen, Stoßkupplungen mit Scherbolzen, Normal-Reduzierkupplungen und Dreh-Reduzierkupplungen mit Schraub- oder Keilverschluss.
Sie gibt außerdem Empfehlungen für die laufende Produktionskontrolle.
Diese Kupplungen werden hauptsächlich in temporären Konstruktionen eingesetzt. Jede dieser Kupplungen lässt sich auf jeweils mindestens einer Seite an einem Stahl- oder Aluminiumrohr von 48,3 mm Durchmesser befestigen. Für die jeweils andere Seite von Reduzierkupplungen legt diese Norm Anforderungen an den Durchmesser und die Wanddicke der entsprechenden Rohre fest.
Bei der Prüfung werden Schraubkupplungen mit einem Drehmoment von 50 Nm und Keilkupplungen mit einem 500 g-Hammer bis zum Prellschlag angezogen.
Sonstige spezielle Halbkupplungen, wie z. B durch Nieten angebrachte Halbkupplungen, die hauptsächlich für Bauteile vorgefertigter Arbeitsgerüste verwendet werden, liegen nicht im Anwendungsbereich dieser Norm.
ANMERKUNG   Anhang B enthält Angaben zum Entwurf mit Hilfe von Spezialkupplungen.

Raccords, goujons d'assemblage et semelles pour étaiements et échafaudages - Partie 2: Raccords spéciaux - Exigences et modes opératoires d'essai

L’EN 74 2 spécifie :
   les matériaux ;
   les exigences de conception ;
   les valeurs spécifiées de résistance et de rigidité qu’un raccord doit respecter dans le cadre des essais ;
   les modes opératoires d’essai et l’évaluation ;
pour les raccords spéciaux suivants :
   demi-raccords boulonnés ou par clavette, raccords de prolongation avec broches travaillant en cisaillement, raccords réducteurs orthogonaux et à angle variable.
Elle émet des recommandations relatives au contrôle de la production en cours.
Ces raccords sont principalement utilisés en tant qu’équipements temporaires de chantiers. Chaque raccord peut être monté au moins sur un tube d’acier ou d’alliage d’aluminium de 48,3 mm de diamètre. Pour les raccords réducteurs, la présente norme définit les exigences de diamètre et d’épaisseur de paroi de tubes.
Pour les essais, les raccords boulonnés sont serrés selon un couple de 50 Nm et les raccords par clavette à l’aide d’un marteau de 500 g jusqu’au refus.
Les autres demi-raccords spéciaux, tels que les demi-raccords rivetés, utilisés principalement pour les éléments d’échafaudages préfabriqués, ne relèvent pas du domaine d’application de la présente norme européenne.
NOTE   Certaines informations sur la conception à l’aide de raccords spéciaux figurent en Annexe B.

Spojke, vezne centične spojke in podnožne plošče za delovne in nosilne odre - 2. del: Specialne spojke - Zahteve in preskusni postopki

General Information

Status
Published
Publication Date
14-Oct-2008
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
07-Oct-2008
Due Date
12-Dec-2008
Completion Date
15-Oct-2008

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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Kupplungen, Zentrierbolzen und Fußplatten für Arbeitsgerüste und Traggerüste - Spezialkupplungen - Teil 2: Anforderungen und PrüfverfahrenRaccords, goujons d'assemblage et semelles pour étaiements et échafaudages - Partie 2: Raccords spéciaux - Exigences et modes opératoires d'essaiCouplers, spigot pins and baseplates for use in falsework and scaffolds - Part 2: Special couplers - Requirements and test procedures91.220Gradbena opremaConstruction equipmentICS:Ta slovenski standard je istoveten z:EN 74-2:2008SIST EN 74-2:2008en01-december-2008SIST EN 74-2:2008SLOVENSKI

STANDARD
SIST EN 74-2:2008

EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 74-2September 2008ICS 91.220 English VersionCouplers, spigot pins and baseplates for use in falsework andscaffolds - Part 2: Special couplers - Requirements and testproceduresRaccords, goujons d'assemblage et semelles pourétaiements et échafaudages - Partie 2: Raccords spéciaux- Exigences et modes opératoires d'essaiKupplungen, Zentrierbolzen und Fußplatten fürArbeitsgerüste und Traggerüste - Spezialkupplungen - Teil2: Anforderungen und PrüfverfahrenThis European Standard was approved by CEN on 9 August 2008.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN 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 translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36

B-1050 Brussels© 2008 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 74-2:2008: ESIST EN 74-2:2008

EN 74-2:2008 (E) 2 Contents Page Foreword..............................................................................................................................................................3 Introduction.........................................................................................................................................................4 1 Scope......................................................................................................................................................5 2 Normative references............................................................................................................................5 3 Terms and definitions...........................................................................................................................6 4 Symbols..................................................................................................................................................8 5 Types and classification of special couplers.....................................................................................9 6 Transmissible internal forces, moments and related stiffnesses..................................................10 6.1 General..................................................................................................................................................10 6.2 Half coupler..........................................................................................................................................11 6.3 Sleeve coupler with shear studs (SS)................................................................................................12 6.4 Reduction coupler...............................................................................................................................12 7 Reference tubes/bar for coupler tests...............................................................................................14 8 General requirements..........................................................................................................................15 8.1 Materials...............................................................................................................................................15 8.2 Design...................................................................................................................................................15 8.3 Manufacturer’s drawings....................................................................................................................17 8.4 Production control...............................................................................................................................17 9 Tests methods and evaluation of results..........................................................................................17 9.1 General..................................................................................................................................................17 9.2 Half Couplers........................................................................................................................................18 9.3 Sleeve couplers with shear studs (SS)..............................................................................................27 9.4 Reduction couplers.............................................................................................................................30 10 Designation..........................................................................................................................................30 11 Marking.................................................................................................................................................31 12 Test report............................................................................................................................................31 13 Assessment..........................................................................................................................................31 14 Product Manual....................................................................................................................................31 Annex A (informative)

Ongoing production control......................................................................................33 Annex B (informative)

Information about the design of temporary works structures...............................35 B.1 General..................................................................................................................................................35 B.2 Structural design.................................................................................................................................35 Bibliography......................................................................................................................................................41

SIST EN 74-2:2008

EN 74-2:2008 (E) 3 Foreword This document (EN 74-2:2008) has been prepared by Technical Committee CEN/TC 53 “Temporary works equipment”, the secretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by March 2009, and conflicting national standards shall be withdrawn at the latest by March 2009. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights. The couplers specified in this European Standard are intended for use in temporary works for example scaffolds erected in accordance with EN 12811-1 and falsework erected in accordance with EN 12812. In accordance with the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. SIST EN 74-2:2008

EN 74-2:2008 (E) 4 Introduction This is the second of three parts of a standard for couplers. EN 74-1 deals with common types of friction couplers. EN 74-2 deals with other less common types of friction couplers and other couplers. EN 74-3 deals with non-adjustable base plates and loose spigot pins. EN 74-2 is not intended to prevent the development of other types of couplers; for example couplers may be manufactured in aluminium or other materials or be designed for use with steel or aluminium tubes with outside diameters different from those specified in this standard. Whilst such couplers cannot conform to this standard, it is recommended that the principles of this standard are considered in their design and assessment. NOTE In the text of this standard, the term "loose spigot” is used instead of the "spigot pin” in the title. SIST EN 74-2:2008

EN 74-2:2008 (E) 5 1 Scope EN 74-2 specifies:  materials;  design requirements;  specified values for resistances and stiffnesses which a coupler has to achieve under test;  test procedures and assessment; for the following special couplers:

 screw or wedge half couplers, sleeve couplers with shear studs, right angle reduction couplers and swivel reduction couplers. It gives recommendations for on-going production control. These couplers are for use principally in temporary works.. Each coupler is able to be fixed to at least one side to one 48,3 mm diameter steel or aluminium tube. For the other side of reduction couplers, this standard specifies requirements for the diameter and wall thickness of tubes. For testing, screw couplers are tightened with a torque of 50 Nm and wedge couplers are tightened with a 500 g hammer until the jarring blow. Other special half couplers such as half couplers attached by riveting, used mainly for members of prefabricated scaffolds, are outside the scope of this European Standard. NOTE Information on design using special couplers is given in Annex B. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 74-1:2005, Couplers, spigot pins and baseplates for use in falsework and scaffolds — Part 1: Couplers for tubes — Requirements and test procedures EN 1090-2:2008, Execution of steel structures and aluminium structures — Part 2: Technical requirements for steel structures EN 12811-1:2003, Temporary works equipment — Part 1: Scaffolds — Performance requirements and general design EN 12811-2:2004, Temporary works equipment — Part 2: Information on materials EN 12811-3:2002, Temporary works equipment — Part 3: Load testing EN ISO 898-1:1999, Mechanical properties of fasteners made of carbon steel and alloy steel — Part 1: Bolts, screws and studs (ISO 898-1:1999) SIST EN 74-2:2008

EN 74-2:2008 (E) 6 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 12811-1:2003 and EN 74-1:2005 and the following apply. 3.1 half coupler (HW, HT) coupler which connects a tube of 48,3 mm diameter to another member either by means of welding (HW) or by means of a welded-in threaded element (HT) NOTE See Figures 1 and 2.

Key

a profile of welding Figure 1 — Half coupler connected by welding (HW) SIST EN 74-2:2008

EN 74-2:2008 (E) 7
Key

a profile of welding t thickness of the head of welded-in threaded element 1 welded-in threaded element (bolt, screw, stud, threaded rod) Figure 2 — Half coupler for connection with a welded in threaded element (HT) 3.2 sleeve coupler with shear studs (SS) coupler for connecting 48,3 mm tubes end to end by means of a pair of shear studs on each side engaging with two predetermined holes in each tube NOTE See Figure 3. Where required, a manufacturer may specify the use of a loose spigot (not shown on Figure 3).

Figure 3 — Sleeve coupler with shear studs (SS) SIST EN 74-2:2008

EN 74-2:2008 (E) 8 3.3 reduction coupler (RR and RS) right angle coupler (RR) or swivel coupler (RS) for connecting two tubes with different diameters of which one tube has a diameter of 48,3 mm NOTE See Figure 4.

Figure 4 — Reduction coupler as swivel coupler (RS) 4 Symbols For the purpose of this European Standard, the following symbols apply: ck

characteristic stiffness of a longitudinal spring; Fs slipping force in kN; Ff failure force in kN; Fp pull apart force in kN; Fq share force in kN; MB bending moment in kNm; c3(1),MB bending stiffness in kNm/rad; Fs,c specified value for slipping force in kN; Ff,c specified value for failure force in kN; Fp,c specified value for pull apart force in kN; SIST EN 74-2:2008

EN 74-2:2008 (E) 9 MB,c specified value for bending moment in kNm; c3(1),MB,c
specified value for bending stiffness in kNm/rad;

displacement in millimetres of the transverse tube under load relative to a tube or solid bar in rotational tests; ûi displacement in millimetres of a coupler under load relative to a tube or solid bar; û10 indentation in millimetres; P test load in kN; Pind test load for indentation in kN; Pf,ult ultimate failure force in kN; Pp,ult ultimate pull apart force in kN; Pq,ult ultimate share force in kN; 3 specified angle of rotation of a coupler in degrees. 5 Types and classification of special couplers The types of special couplers are listed in Table 1. The classification is given in Table 2. SIST EN 74-2:2008

EN 74-2:2008 (E) 10

Table 1 — Types of couplers Type Identification Arrangement HW Connection of a tube to a member with a coupler directly welded to the member

Half coupler HT Connection of a tube to a member with a coupler which incorporates a welded in threaded element Sleeve coupler with shear studs SS Tubes connected end to end coaxially using holes in the tubes and studs

Right angle RR Tube of 48,3 mm diameter connected to a tube of another diameter at a right angle

Reduction coupler Swivel RS Tube of 48,3 mm diameter connected to a tube of another diameter at any angle

Table 2 — Classification of couplers Class Type of coupler A B unclassified Half coupler v v — Sleeve coupler with shear studs — — v Reduction coupler

— — v

6 Transmissible internal forces, moments and related stiffnesses 6.1 General In general a connection between two members is able to transmit three internal forces and three moments at right angle. There are related stiffnesses. The connection of a tube to another member by a threaded element fixed half coupler (HT) or by weldable half coupler (HW) is designed to transmit three forces. Additionally, a Class B half coupler connected by a welded-in threaded element (HT) is designed to transmit one bending moment and a Class B screw weldable half coupler (HW) is designed to transmit two bending moments as listed in Table 3. A sleeve coupler with shear studs (SS) is designed to transmit one force and one bending moment as listed in Table 4. A right angle reduction coupler (RR) is designed to transmit three forces at right angle in three directions as listed in Table 5. A swivel reduction coupler (RS) is designed to transmit one force as listed in Table 6. NOTE The influence of the moments resulting from eccentricities of the connection is considered in the test. SIST EN 74-2:2008

EN 74-2:2008 (E) 11 6.2 Half coupler Table 3 shows the structural parameters which are specified. Table 3 — Structural parameters for half couplers (HT and HW) Class A B HW Structural parameters (see Figure 5) HW/HT Screw coupler Wedge coupler HT Slipping force Fs v v v v Failure force Ff v v v v Pull apart force Fp v v v v Shear force Fq v v v v Bending moment MB,x — v — — Force or moment

Bending moment MB,y — v v v Bending stiffness cϕ,MB,x — v — — Connection stiffness Bending stiffness cϕ,MB,y — v v v v Structural parameters are specified in Table 8.

Key x,y
direction of principal axis
Figure 5 — Forces and moments for a half coupler SIST EN 74-2:2008

EN 74-2:2008 (E) 12 6.3 Sleeve coupler with shear studs (SS) Table 4 shows which structural parameters are specified. Table 4 — Structural parameters for a sleeve coupler with shear studs (SS) Structural parameter See Figure 6 Unclassified Failure force Ff v Bending moment MB v v Structural parameters are specified in Table 8.

Figure 6 — Forces and moments for a sleeve coupler with shear studs (SS) 6.4 Reduction coupler Tables 5 and 6 show the structural parameters specified. Table 5 — Structural parameters for a right angle reduction coupler type (RR) Tube Structural parameter see Figure 7 Unclassified Slipping force Fs,1 v 1

Diameter 48,3 mm Failure force Ff,1 v Slipping force Fs,2 v 2
Diameter different from 48,3 mm Failure force Ff,2 v

Pull-apart force Fp v v Structural parameters are specified in Table 8. SIST EN 74-2:2008

EN 74-2:2008 (E) 13

Key 1 tube 1 48,3 mm outside diameter 2 tube 2 of a different outside diameter Figure 7 — Forces for a right angle reduction coupler

Table 6 — Structural parameters for a swivel reduction coupler type (RS) Tube Structural parameter (see Figure 8) Unclassified Slipping force Fs,1 v 1

Diameter 48,3 mm Failure force Ff,1 v Slipping force Fs,2 v 2

Diameter different from 48,3 mm Failure force Ff,2 v v Structural parameters are specified in Table 8.

SIST EN 74-2:2008
EN 74-2:2008 (E) 14

Key 1 tube 1 48,3 mm outside diameter 2 tube 2 of a different outside diameter Figure 8 — Forces for a swivel reduction coupler (RS) 7 Reference tubes/bar for coupler tests For the purpose of testing, reference tubes and solid bars with a diameter of 48,3 mm shall be in accordance with EN 74-1. The tubes used for testing reduction couplers with diameters other than 48,3 mm shall be in accordance with Table 7, in which the diameters may have a deviation of ± 0,5 mm. Table 7 — Steel reference tubes RTR(n) for reduction couplers other than 48,3 mm outside diameter Steel reference n Outside diameter

(mm) Wall thickness
(mm) Wall thickness tolerance (including finishing) (mm) Yield stress

(N/mm²) 1 38,0 2 42,4 3 60,3 3,2 4 63,5 4,0 RTR(n) 5 76,1 4,5 +0,1 -0,2 235 ≤ ReH ≤ 265

SIST EN 74-2:2008

EN 74-2:2008 (E) 15 8 General requirements 8.1 Materials All members of couplers shall conform to the requirements specified in clause 6.1 of EN 74 -1:2005. The bodies of half couplers (HW and HT) shall conform to the welding requirements for execution Class 2 (EXC2) of EN 1090-2:2008. A threaded element shall be weldable and correspond as a minimum to M14 and strength Class 5.6 specified in EN ISO 898-1:1999. 8.2 Design 8.2.1 All couplers and coupler members shall conform to the requirements specified in clause 6.2.2, 6.2.3 and 6.2.6 of EN 74-1:2005. 8.2.2 A coupler of a specified type shall conform to all requirements specified in Table 8. It means for any structural parameter that the evaluated test results shall achieve at least the specified values in this standard. Except for indentation, each value evaluated from a set of tests shall be equal to or greater than the specified value. NOTE The slipping resistance is dependent on the bolt tension. For a given torque this tension is considerably increased when the integral friction coefficient on the thread is low. This integral friction coefficient is significantly influenced by the type of corrosion protection and by the lubrication of the bolt and nut connection. 8.2.3 Half couplers may be manufactured from parts of swivel couplers in accordance with EN 74-1 (half swivel couplers) or as a separate member. For a half coupler (HT), the threaded element for bolting to the other member shall be welded into the half coupler body with a surrounding line of welding. The body of a half coupler (HW) shall be welded to the other member with a surrounding line of welding to exclude air. The welding procedures shall be carried out in accordance with execution Class 2 (EXC2) of EN 1090-2:2008. 8.2.4 Sleeve couplers with shear studs shall be able to connect tubes with holes in accordance with the dimensions given below and to conform to the requirements given in 8.2.2. The distance between the end of a tube and each centre of the hole shall be 32,5 mm ± 1 mm. The diameter of the hole shall be 14 mm ± 0,5 mm. If required by the manufacturer a loose spigot should be used. SIST EN 74-2:2008

EN 74-2:2008 (E) 16 Table 8 — Tests parameters and specified values Specified values Class Type Property parameter Test clause Test parameter A B unclas-sified ∆1 ≤ 7 mm 7,0 kN 10,0 kN — Slipping force Fs,c 9.2.2 1 ≤ ∆2 ≤ 2 mm 10,0 kN 15,0 kN — Failure force

Ff,c 9.2.3 Pf,ult 14,0 kN 20,0 kN — Pull-apart force

Fp,c 9.2.4 Pp,ult 20,0 kN 30,0 kN — Pind = 4,7 kN ≤ 1,5 mm — — Indentation ∆10 9.2.7 Pind = 6,67 kN — ≤ 1,5 mm — Shear force

Fq,c 9.2.5 Pq,ult 14,0 kN 20,0 kN — cϕ1,MB,y,c MB/1,65 = 0,48 kNm — 15,0 kNm/rad — Bending stiffness on steel tube cϕ2,MB,y,c MB = 0,8 kNm — 6,0 kNm/rad — cϕ1,MB,y,c MB/1,65 = 0,48 kNm — 13,0 kNm/rad — Bending stiffness on aluminium tube cϕ,2,MB,y,c MB = 0,8 kNm — 5,0 kNm/rad — Half coupler (HW,HT) Bending moment MB,y,c 2MB — 1,6 kNm — cϕ1,MB,x,c MB/1,65 = 0,48 kNm — 15,0 kNm/rad — Only for screw coupler (HW) Bending stiffness on steel tube cϕ2,MB,x,c 9.2.6 MB = 0,8 kNm — 6,0 kNm/rad — cϕ1,MB,x,c MB/1,65 = 0,48 kNm — 13,0 kNm/rad — Bending stiffness on aluminium tube cϕ2,MB,x,c MB = 0,8 kNm — 5,0 kNm/rad —

Bending moment
MB,x,c

2MB — 1,6 kNm — Failure force Ff,c 9.3.1 Pf,ult — — 40,0 kN Sleeve coupler with shear studs (SS) Bending moment MB,c 9.3.2 ∆4 ≤ 5 mm — — 1,4 kNm ∆1 ≤ 7 mm — — 7,0 kN Slipping force Fs,c 9.4.2 1 ≤ ∆2 ≤ 2 mm — — 10,0 kN Failure force Ff,c 9.4.2 Pf,ult — — 20,0 kN Pull apart force Fp,c 9.4.3 Pp,ult — — 20,0 kN Right angle reduction coupler (RR) Indentation ∆10 9.4.4 Pind = 6,67 kN — — ≤ 1,5 mm SIST EN 74-2:2008

EN 74-2:2008 (E) 17 Table 8 (continued) Specified values Classes Type Property parameter Test clause Test parameter A B unclas-sified ∆1 ≤ 7 mm — — 7,0 kN Slipping force Fs,c 9.4.2 1 ≤ ∆2 ≤ 2 mm — — 10,0 kN Failure force Ff,c 9.4.2 Pf,ult — — 14,0 kN Swivel reduction coupler (RS) Indentation ∆10 9.4.4 Pind = 4,7 kN — — ≤ 1,5 mm 8.3 Manufacturer’s drawings For each coupler model, the manufacturer shall record on the drawings sufficient information for unambiguous identification and as a base for subsequent inspection. This includes: a) geometry; b) dimensions and tolerances; c) mass with tolerance; d) material specification for each element of the coupler; e) type of surface protection of each element of the coupler. 8.4 Production control 8.4.1 An appropriate method of quality control during each production programme shall ensure that couplers satisfy the performance requirements of this standard and that they conform to the manufacturer’s drawings. When the ongoing production control follows one of the inspection methods set out in Annex A, it can be assumed that the couplers produced under this regime conform to the requirements of this clause. 8.4.2 When ongoing production control procedures differ from those recommended in Annex A, they should be drawn up by a person competent do so. NOTE Although it is not a requirement of this standard, it is recommended that manufacturers submit their production control procedures periodically to third party inspections. 9 Tests methods and evaluation of results 9.1 General Basic requirements for testing are given in EN 12811-3. Requirements for testing shall conform to clauses 7.1.2 to 7.1.11 of EN 74-1:2005. The minimum number of tests carried out on different types and classes of each coupler shall be in accordance with Table 9. SIST EN 74-2:2008

EN 74-2:2008 (E) 18 Any aspects of the evaluation of tests results where not specified in this standard shall be carried out in accordance with EN 12811-3. Table 9 — Minimum number of tests for each coupler type Number of tests Type of coupler Type of test RTR RTS1 RTS2 RTS3 RTA RB Slipping force Fs — 10 — — 5 — Failure force Ff — — — — — 5 Pull apart force Fp — — — — — 5 Shear force Fq — — — — — 5 Indentation — — 5 — — — Half coupler (HW,HT) Cruciform bending moment MB,y Only for Class B — 10 — — 5 — Only for Class B screw coupler (HW) Cruciform bending moment MB,x — 10 — — 5 — Failure force Fs — 5 — — — — Sleeve coupler with shear studs (SS) Bending moment MB —

— 5 — — Slipping force Fs 10 10 — — — — Failure force Ff — — — — — 5a Pull-apart force Fp — — — — — 5a Right angle reduction coupler (RR) Indentation 5 — 5 — — — Slipping force Fs 10 10 — — — — Failure force Ff — — — — — 5a Swivel reduction coupler (RS) Indentation 5 — 5 — — — NOTE For reference tubes, see Table 7 and Clause 5 of EN 74-1:2005. a If RB is not available a tube with the same outside diameter may be used. 9.2 Half Couplers 9.2.1 General If a coupler can be used both as a weldable half coupler (HW) (without a welded-in threaded element) and as a half coupler connected by a welded-in threaded element (HT), only the less favourable coupler type need be tested. 9.2.2 Slipping force Fs of a half coupler 9.2.2.1 Purpose of test To determine the resistance Fs of a coupler to slipping along a tube and the relative displacements between the tube and the other member. SIST EN 74-2:2008

EN 74-2:2008 (E) 19 9.2.2.2 Test arrangements Connect the coupler to a member by welding (HW) or by welded-in threaded element (HT). If both applications are to be used, tests shall be carried out with couplers connected by welding (HW). Provide equipment to apply a test load P to the tube at the axis of the tube, see Figure 9. Make provision for measuring the displacement û2 between the tube and the member and û1 between the back of the coupler and the tube.

Key 1 rigid structural member 2 reference tube 3 half coupler Figure 9 — Test arrangement for slipping test of a weldable half coupler 9.2.2.3 Requirements for pre-loads The zero for both load–displacement measurements shall be set under a pre-load of 0,4 kN. 9.2.2.4 Test procedure The connection shall be subjected to a load P(i) applied axially. The displacements ûi of the couplers shall be measured. The test load P(i) shall be increased uniformly at a rate of loading not exceeding 0,3 kN per second until the coupler begins to slip. Thereafter, a rate of slip of 2,0 mm per minute shall not be exceeded. The plotted load displacement curves P(i) = f(ûi) shall include at least one displacement measuring point for every 1,0 kN increase in load P. Load displacement curves P(i) = f(ûi) shall be plotted until either: a) displacement ûi reaches the maximum values given in Table 8; or SIST EN 74-2:2008

EN 74-2:2008 (E) 20 b) test load P reaches a value of twice the specified force given in Table 8; or

c) test load reaches a maximum value Pmax whereafter the load cannot be usefully increased further. 9.2.2.5 Evaluation of test results The slipping force Fs(i) of the specimen is the lowest measured force between a displacement û2 of 1 and 2 mm. Analyse the values of Fs(i) statistically in accordance with 10.5 of EN 12811-3:2002 to determine the 5 % quantile Fs5%. 9.2.3 Failure force Ff of a half coupler 9.2.3.1 Purpose of test To determine the resistance Ff of a coupler at failure. 9.2.3.2 Test arrangement Connect the coupler to a member by welding (HW) or by a welded-in threaded element (HT). If both applications are to be used, tests shall be carried out with a coupler connected by welding (HW). The coupler shall be located touching the abutment, and shall be fixed on the solid bar to prevent the coupler sliding during the test. The abutment shall be on the side of the solid bar remote from the member. Provide equipment to apply a test load P to the tube at the axis of the tube, see Figure 10.

Key 1 rigid structural member 2 reference tube 3 half coupler 4 abutment Figure 10 — Test arrangement for failure test SIST EN 74-2:2008

EN 74-2:2008 (E) 21 9.2.3.3 Test procedure Increase the test load P(i), displacement controlled with not more than 2 mm per minute, until either: a) coupler member fractures; or b) test load P(i) reaches a value after which the load cannot be usefully increased. Each maximum load Pmax and the nature of the failure mode of the coupler shall be recorded. 9.2.3.4 Evaluation of test results Analyse the values of Pmax statistically in accordance with 10.5 of EN 12811-3:2002 to determine the 5 % quantile Fs5%. Apply an additional partial safety factor R2 which shall be taken either as 1,25 or may be determined in accordance with EN 12811-3. 9.2.4 Pull-apart force Fp of a half coupler 9.2.4.1 Purpose of test To determine the resistance of Fp given by the coupler to separation of the tube and the structural member. 9.2.4.2 Test arrangement Connect the coupler to a structural member by welding (HW) or by welded-in threaded element (HT). If both applications shall be used, the test shall be carried out with the coupler connected by welded-in threaded element (HT). Provide equipment to apply half the test load P/2 to the tube at two points equidistant from the axis of the coupler, see Figure 11.

Key 1 rigid structural member 2 half coupler 3 solid reference bar F
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