GB national standards MT Coal Industry Standards GB / T National Recommended Standard HB Aviation Industry Standards GBn national standard (internal distribution) QJ Aerospace Industry standards GJB national military standards QB, SG Ministry of Light Industry standards ZB Industry Standards (Professional Standards) JZ, JG urban and rural Environmental Protection Department standards ZBn Industry Standard (Internal Distribution) CB China Shipbuilding Corporation standards ZJB professional military standards LD Labor and Personnel Standards JB Machinery Industry Standard (formerly) Machinery Industry Ministry standards JC National Building Materials Bureau standards JB / Z (former) Ministry of Machinery Industry guidance document JJC National Bureau of Metrology standards EJ (former) Ministry of Nuclear Industry standards CAS China Association for Standardization standards YB Metallurgical Department standards CVA China valve industry standards HG Chemical Industry standards Q / TH (former) Machinery Industry Ministry of Chemical General Machinery professional standards SY (former) Ministry of Petroleum standards JB / TQ Machinery and Electronic Industry General Machinery Industry Internal Standards SD hydraulic power standard H high pressure pipe, fittings and fasteners universal design standards Foreign standard code ISO international standards AISI American Iron and Steel Institute standards ANSI American National Standard API American Petroleum Institute standards BS British National Standard MSS American Valve and Fitting Manufacturer Standards Association standard DIN German national standard AWS American Welding Association standard NF French national standard ASI American Society of Standards JIS Japanese Industrial Standards MIL US military standards ASME American Society of Mechanical Engineers standards JPI Japan Petroleum Institute standards ASTM American Society for Testing and Materials Standards