| Manufacturer country / location | Manufacturer | Certificate No | | | Issue date | Apparatus | |
|---|
| 80 |  Australia |  |
| 4 | Austria | |
| 1 | Belgium | |
| 1 | Brazil | |
| 19 | Canada | |
| 26 | China | |
| 3 | Czech Republic | |
| 10 | Denmark | |
| 14 | Finland | |
| 44 | France | |
| 2 | France Metropolitain | |
| 330 | Germany | |
| 1 | Hungary | |
| 6 | India | |
| 4 | Ireland | |
| 2 | Israel | |
| 25 | Italy | |
| 44 | Japan | |
| 79 | Korea, Republic of | |
| 2 | Latvia | |
| 3 | Malaysia | |
| 5 | New Zealand | |
| 21 | Norway | |
| 21 | Poland | |
| 6 | Portugal | |
| 1 | Russian Federation | |
| 7 | Singapore | |
| 2 | Slovenia | |
| 1 | South Africa | |
| 2 | Spain | |
| 11 | Sweden | |
| 16 | Switzerland | |
| 12 | Taiwan | |
| 1 | Thailand | |
| 13 | The Netherlands | |
| 398 | United Kingdom | |
| 272 |  United States of America | |
| 1 | | ABB Inc (Totalflow®) | |
| 4 | | ABB Inc. | |
| 9 | | Adalet, A Scott Fetzer Co. | |
| 2 | | Adalet/ Scott Fetzer Company | |
| 1 | | Adalet/Scott Fetzer | |
| 4 | | Adalet/Scott Fetzer Co. | |
| 4 | | ADS Environmental Services | |
| 1 | | Atlantic Scientific Corporation | |
| 1 | | Baldor | |
| 17 | | Baldor Electric Company | |
| 1 | | Barksdale Inc. | |
| 6 | | Bently Nevada LLC | |
| 1 | | Brodie Meter Co. LLC | |
| 1 | | Brooks Instrument | |
| 1 | | Brooks Instrument LLC | |
| 1 | | Bubezi Controls | |
| 1 | | Crystal Engineering Corp. | |
| 6 | | Daniel Measurement and Control Incorporated | |
| 1 | | Detector Electronics Company | |
| 1 | | Detector Electronics Corporation | |
| 5 | | Dixon Bayco | |
| 3 | | EGS Electrical Group LLC | |
| 1 | | Environment One Corporation | |
| 1 | | Expro Meters, Inc. | |
| 2 | | Fairchild Industrial Products Company | |
| 1 | | Fireye, Inc | |
| 1 | | Fireye, Inc. | |
| 5 | | Fisher Controls International LLC | |
| 1 | | Fisher Controls International, LLC | |
| 1 | | FMC Technologies Measurement Solutions | |
| 1 | | FMC Technologies Measurement Solutions Inc. | |
| 2 | | Franklin Fueling Systems | |
| 1 | | Gai-Tronics Corp. | |
| 1 | | Gaumer Process | |
| 2 | | GE Infrastructure Sensing | |
| 1 | | GP:50 Ltd | |
| 1 | | Honeywell Analytics Limited | |
| 2 | | Honeywell Analytics Inc. | |
| 1 | | Honeywell Control Systems Limited | |
| 1 | | Honeywell Enraf Americas Inc. | |
| 3 | | Honeywell International | |
| 2 | | Honeywell International Inc. | |
| 1 | | Honeywell International Industry Solutions | |
| 2 | | HONEYWELL PROCESS SOLUTIONS | |
| 1 | | Honeywell Sensing and Control | |
| 5 | | Industrial Scientific Corporation | |
| 1 | | Industrial Scientific Corp. | |
| 1 | | Intermec Technologies Corporation | |
| 1 | | Invensys Systems, Inc | |
| 1 | | ITT Corporation - BIW Connector Systems | |
| 1 | | ITT Corporation – BIW Connector Systems | |
| 12 | | Joy Mining Machinery | |
| 1 | | Joy Mining Machinery, Inc | |
| 5 | | Joy Mining Machinery, Inc. | |
| 5 | | K-Tek Corp. | |
| 1 | | Killark, Div of Hubbell Inc (Delaware) | |
| 2 | | Knappco Civacon | |
| 1 | | KOEHLER – BRIGHT STAR, Inc. | |
| 1 | | Kurz Instruments Inc. | |
| 1 | | Masoneilan Dresser | |
| 1 | | Micro Motion | |
| 1 | | Micro Motion Inc. | |
| 9 | | Micro Motion, Inc. | |
| 2 | | Mine Safety Appliances | |
| 3 | | Mine Safety Appliances Company | |
| 3 | | Mine Safety Appliances Co. | |
| 1 | | Mine Safety Appliances Co. (Instrument Division) | |
| 1 | | Moore Industries-International, Inc | |
| 1 | | Moore Industries International Inc | |
| 1 | | Ocean Design Incorporated | |
| 1 | | Ohmart/Vega Corp. | |
| 2 | | OPW Fuel Management Systems | |
| 3 | | PARKER HANNIFIN CORPORATION | |
| 1 | | Pelco | |
| 1 | | Pelican Products Inc | |
| 1 | | Pelican Products Inc. | |
| 1 | | Pepperl & Fuchs | |
| 1 | | Pepperl + Fuchs Inc. | |
| 1 | | Physical Acoustics Corporation | |
| 1 | | PMFG LLC | |
| 1 | | Purge Solutions | |
| 1 | | Quest Technologies, Inc. a 3M Company | |
| 1 | | RAE Systems | |
| 2 | | RAE Systems | |
| 2 | | Rae Systems Inc. | |
| 1 | | Rohrback Cosasco Systems | |
| 1 | | Rosemount Analytical Gas Chromatograph Division | |
| 1 | | Rosemount Analytical Incorporated | |
| 1 | | Rosemount Analytical Inc., Process Analytic Division | |
| 1 | | Rosemount Analytical, Gas Chromatographs Division | |
| 3 | | Rosemount Inc | |
| 2 | | Rosemount Incoporated | |
| 21 | | Rosemount Incorporated | |
| 6 | | Rosemount Inc. | |
| 1 | | Rotork Process Controls | |
| 2 | | Spectrex Ltd | |
| 1 | | Sperian Protection Instrumentation LLC | |
| 5 | | Thermon Manufacturing Company | |
| 3 | | Topworx Inc | |
| 3 | | Topworx Incorporated | |
| 1 | | TopWorx Inc. | |
| 1 | | Trimble Navigation Limited | |
| 1 | | Tuthill Corporation | |
| 19 | | Tyco Thermal Controls LLC | |
| 2 | | United Electric Controls Company | |
| 1 | | United Electric Controls Co. | |
| 3 | | Versa Products Company, Inc. | |
| 2 | | Weatherford International Ltd. | |
| 1 | | Wilcoxon Research | |
| 1,489 | | |