JJG 1121-2015 Vortex Precession Flowmeters

JJG 198-1994 Velocity Flowmeter

JJF 1004-2004 Metrological Terms and Their Definitions for Flow Rate GB 3836.1-2000 Electrical apparatus for explosive gas atmospheres—Part 1:General requirements GB 3836.1-2010 Explosive atmospheres—Part 1:Equipment—General requirements GB/T 3836.1-2021 Explosive atmospheres—Part 1:Equipment—General requirements GB 3836.2-2000 Electrical apparatus for explosive gas atmospheres—Part 2:Flameproof enclosure “d” GB 3836.2-2010 Explosive atmospheres—Part 2:Equipment protection by flameproof enclosures "d" GB/T 3836.2-2021 Explosive atmospheres—Part 2:Equipment protection by flameproof enclosures “d” GB 3836.3-2000 Electrical apparatus for explosive gas atmospheres—Part 3:Increased safety “e” GB 3836.3-2010 Explosive atmospheres—Part 3:Equipment protection by increased safety "e" GB/T 3836.3-2021 Explosive atmospheres—Part 3:Equipment protection by increased safety “e” GB 3836.4-2000 Electrical apparatus for explosive gas atmospheres—Part 4:Intrinsic safety“i” GB 3836.4-2010 Explosive atmospheres—Part 4:Equipment protection by intrinsic safety "i" GB/T 3836.4-2021 Explosive atmospheres—art 4:Equipment protection by intrinsic safety “i” GB 3836.5-2004 Electrical apparatus for explosive gas atmosphere—Part 5:Pressurized enclosures"p" GB/T 3836.5-2017 Explosive atmospheres—Part 5:Equipment protection by pressurized enclosure"p" GB/T 3836.5-2021 Explosive atmospheres—Part 5:Equipment protection by pressurized enclosure "p" GB 3836.6-2004 Electrical apparatus for explosive gas atmospheres—Part 6:Oil-immersion"o" GB/T 3836.6-2017 Explosive atmospheres—Part 6:Equipment protection by liquid immersion“o” GB 3836.7-2004 Electrical apparatus for explosive gas atmospheres—Part 7:Powder filling"q" GB/T 3836.7-2017 Explosive atmospheres—Part 7:Equipment protection by powder filling“q” GB 3836.8-2003 Electrical apparatus for explosive gas atmospheres—Part 8:Type of protection “n” GB 3836.8-2014 Explosive atmospheres—Part 8:Equipment protection by type of protection “n” GB/T 3836.8-2021 Explosive atmospheres—Part 8: Equipment protection by type of protection “n” GB 3836.9-1990 Electrical apparatus for explosive atmospheres Encapsulated electrical apparatus "m" GB 3836.9-2006 Electrical apparatus for explosive gas atmospheres—Part 9:Encapsulation "m" GB 3836.9-2014 Explosive atmospheres—Part 9:Equipment protection by type of protection “m” GB/T 3836.9-2021 Explosive atmospheres—Part 9:Equipment protection by encapsulation “m” GB 3836.11-1991 Electrical apparatus for explosive atmospheres-Method of test for ascertainment of maximum experimental safe gap GB/T 3836.11-2008 Explosive atmospheres—Part 11:Equipment protection by flameproof enclosures “d”—Method of test for ascertainment of maximum experimental safe gap GB/T 3836.11-2017 Explosive atmospheres—Part 11:Material characteristics for gas and vapour classification—Test methods and data GB/T 3836.11-2022 Explosive atmospheres—Part 11:Material characteristics for gas and vapour classification—Test methods and data GB 3836.12-1991 Electrical apparatus for explosive atmospheres—Classification of gases or vapours with air according to their maximum experimental safe gaps and minimum igniting currents GB/T 3836.12-2008 Explosive atmospheres—Part 12:Classification of mixtures of gases or vapours with air according to their maximum experimental safe gaps and minimum igniting current GB/T 3836.12-2019 Explosive atmospheres—Part 12:Material characteristics for combustible dusts—Test methods GB 3836.13-1997 Electrical apparatus for explosive gas atmospheres—Part 13:Repair and overhaul for apparatus used in explosive gas atmospheres GB 3836.13-2013 Explosive atmospheres—Part 13:Equipment repair,overhaul and reclamation GB/T 3836.13-2021 Explosive atmospheres—Part 13:Equipment repair,overhaul,reclamation and modification GB 3836.14-2000 Electrical apparatus for explosive gas atmospheres—Part 14:Classification of hazardous areas GB 3836.14-2014 Explosive atmospheres—Part 14:Classification of areas—Explosive gas atmosphere GB 3836.15-2000 Electrical apparatus for explosive gas atmospheres—Part 15:Electrical installations in hazardous areas (other than mines) GB/T 3836.15-2017 Explosive atmospheres—Part 15:Electrical installations design,selection and erection GB 3836.15-2024 Explosive atmospheres—Part 15:Specification of electrical installations design,selection and erection GB 3836.16-2006 Electrical apparatus for explosive gas atmospheres—Part 16:Inspection and maintenance of electrical installation(other than mines) GB/T 3836.16-2017 Explosive atmospheres—Part 16:Electrical installations inspection and maintenance GB/T 3836.16-2022 Explosive atmospheres—Part 16:Electrical installations inspection and maintenance GB 3836.16-2024 Explosive atmospheres—Part 16:Specification of electrical installations inspection and maintenance GB 3836.17-2007 Electrical apparatus for explosive gas atmosphere—Part 17:Construction and use of rooms or buildings protected by pressurization GB/T 3836.17-2019 Explosive atmospheres—Part 17:Equipment protection by pressurized room “p” and artifically ventilated room “v” GB 3836.18-2010 Explosive atmospheres—Part 18:Intrinsically safe system GB/T 3836.18-2017 Explosive atmospheres—Part 18:Intrinsically safe electrical systems GB/T 3836.18-2024 Explosive atmospheres—Part 18:Intrinsically safe electrical systems GB 3836.19-2010 Explosive atmospheres—Part 19:Fieldbus intrinsically safe concept(FISCO) GB 3836.20-2010 Explosive atmospheres—Part 20:Equipment with equipment protection level (EPL) Ga GB/T 3836.21-2017 Explosive atmospheres—Part 21:Application of quality systems for equipment manufacture GB/T 3836.21-2022 Explosive atmospheres—Part 21:Application of quality management systemsfor Ex Product manufacture GB/T 3836.22-2017 Explosive atmospheres—Part 22:Protection of equipment and transmission system using optical radiation GB/T 3836.22-2023 Explosive atmospheres—Part 22:Protection of equipment and transmission system using optical radiation GB/T 3836.23-2017 Explosive atmospheres—Part 23:Group Ⅰ,category EPL Maequipment intended to remain functionalin atmospheres endangered by firedamp and/or coal dust GB/T 3836.24-2017 Explosive atmospheres—Part 24:Equipment protection by special protection“s” GB/T 3836.25-2019 Explosive atmospheres—Part 25:Requirements for process sealing between flammable process fluids and electrical systems GB/T 3836.26-2019 Explosive atmospheres—Part 26:Electrostatic hazards—Guidance GB/T 3836.27-2019 Explosive atmospheres—Part 27:Electrostatic hazards—Test GB/T 3836.28-2021 Explosive atmospheres—Part 28:Non-electrical equipment for explosive atmospheres—Basic method and requirements GB/T 3836.29-2021 Explosive atmospheres—Part 29:Non-electrical equipment for explosive atmospheres—Constructional safety “c”,control of ignition source “b”, liquid immersion “k” GB/T 3836.30-2021 Explosive atmospheres—Part 30:Equipment and components in explosive atmospheres in underground mines GB/T 3836.31-2021 Explosive atmospheres—Part 31:Equipment dust ignition protection by enclosure “t” GB/T 3836.32-2021 Explosive atmospheres—Part 32:Intrinsically safe systems with electronically controlled spark duration limitation GB/T 3836.33-2021 Explosive atmospheres—Part 33:Equipment in adverse service conditions GB/T 3836.34-2021 Explosive atmospheres—Part 34:Equipment assemblies GB/T 3836.35-2021 Explosive atmospheres—Part 35:Classification of areas for explosive dust atmospheres GB/T 3836.36-2022 Explosive atmospheres—Part 36:Electrical safety devices for the control of potential ignition sources from Ex Equipment GB/Z 3836.37-2025 Explosive atmospheres—Part 37:Equipment protection by 2-wire intrinsically safe ethernet concept (2-WISE) GB 4208-1993 Degrees of protection provided by enclosure (IP code) GB/T 4208-2008 Degrees of protection provided by enclosure(IP code) GB/T 4208-2017 Degrees of protection provided by enclosure(IP code) GB 50251-2015 Code for design of gas transmission pipeline engineering GB/T 13609-1999 Natural gas—Sampling guidelines GB/T 13609-2012 Natural gas sampling guidelines GB/T 13609-2017 Natural gas sampling guidelines GB/T 13609-2025 Natural gas—Gas sampling GB/T 13610-2003 Analysis of natural gas by gas Chromatography GB/T 13610-2014 Analysis of natural gas composipion—Gas chromatography GB/T 13610-2020 Analysis of natural gas composition—Gas chromatography GB/T 17747.2-2011 Natural gas—Calculation of compression factor—Part 2:Calculation using molar composition analysis GB 17820-2012 Natural gas OIML R137-1&2:2012