EN 74-2-2008 pdf download.Couplers, spigot pins and baseplates for use in falsework and scaffolds – Part 2: Special couplers – Requirements and test procedures.
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 7.111 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.
9.2.5.3 Test procedure
Increase the test load Pa). displacement controfled with not more than 2 mm per minute. until either:
a) coupler member fractures: or
b) test load P()) reaches a value after which the load cannot be usefully increased.
The test laboratory shall record the maximum load P and the mode of failure of each coupler
9.2.5.4 Evaluation of test results
Analyse the values of statistically in accordance with 10.5 of EN 12811-3:2002 to determine the 5 % quantile Fq5%.
Apply an additional partial safety factor which shall be taken either as 1.25 or may be determined in accordance with EN 12811-3.
9.2.6 Stiffnesses and bending moments of a half coupler
9.2.6.1 Purpose of test
9.2.6.1.1 Bending stiffness c1 UBE and CqMBX and bending moment MB,x
To determine the bending stiffness MBX and C,2MBX and the bending moment resistance of a screw half coupler (HW).
9.2.6.1.2 Bending stiffness Cql,UB,y and C,2MBY and bending moment “By
To determine the bending stiffnesses ce., M8y and C,2MBY and the bending moment resistance of a half coupler,
9.2.6.2 Test arrangements
9.2.6.2.1 Test arrangements for bending stiffness c,, MBx and and bending moment
The coupler is connected by welding to a structural member. Set the equipment up in accordance with Figure 13, in order to apply a test load P to one end of the tube parallel to the axis of the coupler at the distance!, of 750 mm from the axis of the coupler. Provide equipment on the side away from the test load P to measure the change in the angle between the original and the displaced axes of the tube.
9.2.7.3 Test procedure
The coupler shall be subjected to the specified force P, given in Table 8 in accordance with its class.
The coupler shall remain under the force P for at least 10 minutes.
On removal of the coupler from the tubes, the maximum indentation into the tubes caused by a combination of tightening the coupler and the load rind shall be measured.
Each set of measurements shall be used to plot a profile similar to that shown in FIgure 16. The largest value in each case shall be recorded.
9.2.7.4 Evaluation of tests results
Record the maximum value of all the indentations t3 in the Test Report.
9.3 Sleeve couplers with shear studs (SS)
9.3.1 Failure force F1of sleeve couplers
9.3.1.1 Purpose of test
To determine the resistance of a coupler at failure. F1.
9.3.1.2 Test arrangements
The test arrangements for sleeve couplers with shear studs are shown in Figure 17. The coupler shall be placed with studs inserted In the holes In the tubes with a loose spigot where shown in the product manual.
NOTE Where deemed necessary by the manufacturer for normal use, a loose spigot should be Induded In the test arrangement. No loose spigot is shown in Figure 17.EN 74-2-2008 pdf download.