QC Profile

Quality Control & Certification


Most members of Dorrenhaus management team have more than 15 years experience in door closer

industry. Dorrenhaus have paid high attention to the quality management and system construction; research,

develop and manufacture door closer in accordance with international standard since foundation. Dorrenhaus

passed certification for EN ISO9001:2008 and ISO9001:2015 quality management system issued by IFT and

China Certification Center respectively in 2014 and 2016.

Certificate of ISO9001:2008



 Dorrenhaus carry out whole process quality control,  including

raw material (parts) test, process check,  and final product

inspection. The structure of our suface mounted door closer

are as per following picture:


Thereinto, the body, piston, pinion and spring are the key parts

of door closer, they will be inspected by special test equipment

and pass inspection before assembling.


These test equipments includes:

  • Image measuring instrument (for testing the boundary dimension of door closer body);
  • Microhardness and hardness tester (for testing 20Cr carburized layer and hardness of piston and pinion);
  • Spring pressure tester and spring force tester

                             Image measuring instrument


Microhardness tester


              Spring pressure tester


                               Measurement and Detection Laboratory                            Salty Spray Tester


Each cycle in the manufacturing process shall carry out quality transition card system, and check all the parts

and semi-finished products handing over from previous process, if unqualified material are found, they should

be returned to previous process. During the process from assembling to packing, total 9pcs will be taken out

for performance test. After painting, 1pc will be taken out for salt spray test, the adhesive force and antiseptic

ability of the painting will be inspected. In the last process - packaging, inspector will check the appearance

of door closer. Attached please find the sampling inspection standard.


Dorrenhaus self-develop door closer life cycle testing system (1 controlling computer plus 7 testing

platform, 28pcs can be tested at the same time) and 4 sets of life cycle tester (12pcs can be tested at the

same time), each test platform ( life tester) can run all the day, open and close for 12000times every day.

The max. testing life of model: D4016 reach 5mils cycles (testing period continuing for 14months).


                             Door Closer Life Cycle Testing Platform


      Control Panel of Life Cycle Testing System


                      Door Closer Life Cycle Tester   Door Closer Life Cycle Tester & Testing Platform


Normally door closer life cycle test will be made under the following 3 situation:

1) PPAP (Type Tests): before quantity production for a new model;

2) Sampling for large order: if life cycles fail to meet standard or request in the order, goods are not allowed

    to deliver or if delivered, they shall be returned. Anyhow it is rarely happened;

3) Before product certification: only if the same batch pass internal life cycle test, the balanced samples

    could be sent for certification testing. After getting certification, the life cycle of certified model shall be

    tested per quarter, and the test results shall be kept for the annual examination of certification authority.



                                   Test Report for D503 CE Certification


Report for D4000, D8000, D9000 UL Certification


Main international and domestic certification and standard which our door closer passed:

1)American National Standard: ANSI 156.4 Grade 1, life cycle test of 2 mil. cycles

2)American UL228 & UL 10C for 3 hours fire testing

3)European Standard CE: EN1154, life cycle test of 500,000 cycles

4)European Standard CE: EN1634 fire testing

5)China National Standard: QB/T 2698-2005 Grade 1, life cycle test of 1 mil. cycles

6)China Compulsory Product Certification for fire rated door closer



                                      ANSI Certificate for D4000, D8000 & D9000 Series



           CE Certificate for D503, D903, D2000H & D2024



UL 10C Online Certifications Directory for Model D30, D303S, D503, D700, D4016, D8016 & D9016 


By the above mentioned quality management system construction and quality control steps, major quality

problem of Dorrenhaus door closer is seldom happened. Since 2014, Dorrenhaus have been long term

cooperative supplier of global security and protection top brand - A group, and exported nearly

800,000pcs to the customer in 2018.


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