Strength Test

We are evolving safety with repeated strength tests.

The seats of KOTOBUKI SEATING undergo rigorous tests (e.g., load, environment and impact tests) before they take shape. This is only possible by making full use of a lot of data and technology. We are constantly researching the pursuit of safety and durability from new perspectives. The aim of this is to allow everyone to experience a high level of sitting comfort over a long period of time.

Seat Strength Test Method

Seat: Static Load Test

■Test MethodWe apply pressure up to 3.0 kN (306 kgf) using a φ200mm pressure plate at the front-center of the seat
■Judgment Criteria (1) No deformation or looseness of parts should be found with a visual confirmation.
(2) There should be no abnormal shapes or noises when taking a seat.

*Comparison with the test method in the JIS standards…
JIS S 1203 : 1.3 kN
Our criteria : 3.0 kN
Accordingly, our load setting is 2.3 times that of the seat strength test (test category 3) in JIS S 1203.

Seat: Repeated Drop Test

■Test Method We elevate a 35 kg and φ200 mm steel ball bag to a height of 120 mm and then allow it to drop naturally at the front-center of the seat. We repeat this operation up to 30,000 times.
■Judgment Criteria (1) No deformation or looseness of parts should be found with a visual confirmation.
(2) There should be no abnormal shapes or noises when taking a seat.

*Comparison with the test method in the JIS standards…
JIS S 1016 : 15 kg × 9.8 m/s 2 × 0.15 m = 22.05 J × 8,000 times
Our criteria : 35 kg × 9.8m/s 2 × 0.12 m = 41.16 J × 30,000 times
Accordingly, the amount of drop energy per time is 1.9 times that of the repeated impact test in JIS S 1016.

Seat: Repeated Seat Return Test

■Test Method We repeat the automatic seat return operation 100,000 times with no load.
■Judgment Criteria (1) No deformation or looseness of parts should be found with a visual confirmation.
(2) There should be no abnormal shapes in the automatic seat return operation.
(3) There should be no abnormal noises when taking a seat or at the time of the seat return operation.

Surface of the Backrest: Static Load Test

■Test Method We apply pressure up to 1.5 kN (153 kgf) using a φ200mm pressure plate at the front-center of the surface of the backrest.
■Judgment Criteria (1) No deformation or looseness of parts should be found with a visual confirmation.
(2) There should be no abnormal shapes or noises when taking a seat.

*Comparison with the test method in the JIS standards…
JIS S 1203 : 0.56 kN
Our criteria : 1.5kN
Accordingly, our load setting is 2.7 times that of the back strength test (test category 3) in JIS S 1203.

Rear of the Backrest: Static Load Test

■Test Method We apply pressure up to 1.5 kN (153 kgf) using a φ200mm pressure plate at the front-center of the rear of the backrest.
■Judgment Criteria (1) No deformation or looseness of parts should be found with a visual confirmation.
(2) There should be no abnormal shapes or noises when taking a seat.

Writing Table: Static Load Test

■Test Method We apply pressure up to 0.3 kN (31 kgf) using a φ80mm pressure plate at the center of the writing table.
■Judgment Criteria (1) No deformation or looseness of parts should be found with a visual confirmation.
(2) There should be no abnormal shapes or noises during the storage operation.

Outer Surface of the Arms: Static Load Test

■Test Method We apply pressure up to 0.5 kN (51 kgf) using a φ80mm pressure plate at the outer surface of the arms.
■Judgment Criteria (1) No deformation or looseness of parts should be found with a visual confirmation.
(2) There should be no abnormal shapes or noises when taking a seat.

Top Surface of the Arms: Static Load Test

■Test Method We apply pressure up to 0.8 kN (82 kgf) using a φ80mm pressure plate at the front-center of the top surface of the arms.
■Judgment Criteria (1) No deformation or looseness of parts should be found with a visual confirmation.
(2) There should be no abnormal shapes or noises when taking a seat.

■The above are the standard strength and durability test methods for floor-fixed type seats.
■We apply other test methods as reference according to the purpose such as the usage status of each facility (halls/theaters, stadiums, student desk chairs and standalone chairs) and materials.
・JIS S 1203 : Furniture – Chairs and Stools – Strength and Durability Test Method
・JIS L 1096 : Woven and Knitted Fabric Test Method
・JIS A 1415 : Exposure Test Method with a Laboratory Light Source for High Polymer Building Materials
・JIS K 6400 : Soft Foaming Materials – Physical Characteristics (Urethane Foam for Cushions)
・BS5852 : Ignition Evaluation Test with Smoking and Burning for Cloth-covered Seats