Summary of Construction of Special Gas System EngineeringSpecial gas systemIntroduction:Welding construction of special gas system engineering should generally follow the requirements of GB 50646 "Technical Specification for Special Gas System Engineering", and also conform to the current national standard "Code for Construction and Acceptance of Field Equipment and Industrial Pipeline Welding Engineering".Key word:Special gas construction, standard.General Requirements for Construction of Special Gas System EngineeringStainless steel pipes used in special gas systems should be welded by fully automatic rail welder and protected by high purity argon. Measuring instruments for installation and test shall be qualified and used within the validity period. Special construction schemes must be worked out before construction of special gas system projects, and implemented after approval by the owners. Major equipment materials should provide necessary information when entering the site:Product qualification certificate, quality assurance certificate and performance test report;Technical documents for product installation, use, maintenance and test requirements;Product specifications, models, quantities, equipment accessories and special tools.CONCLUSION OF CONSTRUCTION OF SPECIAL GAS SYSTEM ENGINEERINGIf the equipment used in special gas system does not conform to the above-mentioned specifications, it shall not be used in engineering. When the equipment materials are accepted and the welding specimens are appraised, the technical personnel of the construction unit shall verify it on site.