Shuanglong Longping East Road, Longgang District, Shenzhen City. The reexamination center welder certificate is at Shuanglong Longping East Road, Longgang District, Shenzhen City. The welder certificate covers melting welding and thermal cutting operations (electric welding, gas welding, arc welding, electric welding and gas cutting, and others). It is issued by the Work Safety Supervision Administration. Issued; Welders are special jobs and must have a certificate to work. Without a certificate, employment is not allowed.