What should linked chairs be able to endure?

The EN 14703 test explained:

Part 1 of the test is carried out with a row of 11 chairs, which are attached to each other by 10 links.
Part 2 of the test is carried out with a row of 5 chairs and 4 links.

Part 1:
A.
The pull over test. The outer legs of the two outer seats of a row of 11 linked chairs are fixed to the rear against an edge of a maximum of 12 mm high.
Stand behind the seats and grab only the middle seat at the backrest. Pull the whole row backwards until all chairs lay down with the back on the floor and then set the row upright again by the same backrest.
With the same procedure, the row must also be pulled  to the front (outer legs of the outer seats now fixed on the front side) until the backrest touches the floor and then back again.

B. The displacement test. The row of 11 chairs is standing on a hard floor with a smooth surface (concrete, linoleum, tile, wood, etc.). The outer legs are fixed again on a edge of max 12 mm.Connect a spring balance on the middle chair at the height of the seat. Pull the chair first forward  and later backwards with a force of 20 kg. The row may, measured on the floor height on the middle seat, bend in both ways only  to a maximum of 20 cm.

Part 2:
C.
The horizontal impact test. Connect a row of five seats with 4 links.
Fix the outer legs on both the front and the back. Place on the outer two seats a weight of 160 kg.
A free hanging weight on which a basketball is placed,  crashes 10 times on the front and 10 times on the rear of the middle chair at the height of the seat.
The weight including the ball is 50 kg and is released at a distance of 60 cm  on the middle chair.

Following these 3 tests,  this is what your chair and link should be able to endure:

A. On link and the point where it hooks to the chair a lot of force is exerted. The two links of the centre chair must be so strong that the weight of five seats on the right and five seats left can be pulled over. The middle seat itself must be able to take the weight of 10 chairs.

B. The difficulty in the displacement test is minimising the occurrence of play between the coupling and seat. In the row of 11 chairs there are 10 links in which on the left and right side some play can occur. A total of 20 points of possible slack. Even minimal play works cumulatively through the following chairs and makes it almost impossible to pass this test.

C. In this way the strength of the coupling for multiple impact moments is tested. But also the strength of the linked chair due to the loading of 160 kg. The 20 collisions of 50kg give evidence that the combination of chair and link can handle a high load.

The construction of a coupling in accordance with EN 14703 requires a specific and careful approach.
At least 95% of the current  links and ways of linking do not meet this test.
The Chairing system passes this test and can be used on hundreds of chair models..