| Applicant country / location | Applicant | Certificate No | | | Issue date | Manufacturer | Apparatus | |
|---|
| 102 |  Australia |  |
| 1 | Austria | |
| 7 | Belgium | |
| 25 | Canada | |
| 32 | China | |
| 1 | Czech Republic | |
| 8 | Denmark | |
| 5 | Finland | |
| 26 | France | |
| 272 | Germany | |
| 7 | India | |
| 2 | Ireland | |
| 2 | Israel | |
| 19 | Italy | |
| 48 | Japan | |
| 50 | Korea, Republic of | |
| 1 | Latvia | |
| 2 | New Zealand | |
| 15 | Norway | |
| 5 | Poland | |
| 2 | Russian Federation | |
| 4 | Singapore | |
| 4 | South Africa | |
| 1 | Spain | |
| 16 | Sweden | |
| 17 | Switzerland | |
| 2 | Thailand | |
| 6 | The Netherlands | |
| 1 | Turkey | |
| 322 | United Kingdom | |
| 258 |  United States of America | |
| 1 | | Industrial Scientific Corporation | |
| 5 | | ABB Inc. | |
| 5 | | Adalet, A Scott Fetzer Co. | |
| 1 | | AMETEK Drexelbrook | |
| 2 | | Amphenol Industrial | |
| 5 | | Amphenol Industrial Operations | |
| 1 | | ASCO | |
| 1 | | ASCO Valve, Inc. | |
| 1 | | Atlantic Scientific Corporation (MTL Global Surge Technologies) | |
| 1 | | Baker Hughes Inc. | |
| 4 | | Baldor Electric Company | |
| 1 | | Baseline-Mocon Inc. | |
| 5 | | Bently Nevada LLC | |
| 4 | | Brodie Meter Co. LLC | |
| 3 | | Brooks Instrument LLC | |
| 1 | | Crane Valve Services | |
| 1 | | Crystal Engineering Corp. | |
| 2 | | Daniel Measurement and Control Incorporated | |
| 3 | | Deere & Company | |
| 5 | | Detector Electronics Corporation | |
| 1 | | EGS Electrical Group LLC | |
| 1 | | Eveready Battery Co. Inc. | |
| 1 | | Federal Signal Corporation | |
| 1 | | Federal Signal Corp. | |
| 2 | | Fisher Controls a Division of Emerson Process Management | |
| 1 | | Fisher Controls International Inc. | |
| 2 | | Fisher Controls International LLC | |
| 1 | | Fisher Controls International, Inc. | |
| 1 | | Fisher Controls International, LLC | |
| 1 | | Flowserve Corporation | |
| 1 | | Flowserve US Inc | |
| 3 | | Fluid Components International LLC | |
| 1 | | FMC Technologies Measurement Solutions Inc. | |
| 1 | | FMC Technologies Measurements Solutions Inc. | |
| 1 | | GE Infrastructure Sensing Inc. | |
| 1 | | GE Infrastructure Sensing, Inc. | |
| 1 | | GP:50 Ltd | |
| 5 | | Hazardous Location Solutions LLC | |
| 2 | | Honeywell Analytics | |
| 1 | | Honeywell Analytics Inc. | |
| 3 | | Honeywell International | |
| 3 | | HONEYWELL INTERNATIONAL Inc. | |
| 2 | | Industrial Scientific Corporation | |
| 2 | | Industrial Scientific Corp. | |
| 2 | | Industrial Scientific Co. | |
| 1 | | Infinova LLC. | |
| 2 | | Intermec Technologies Corporation | |
| 1 | | Intermec Technologies Corp. | |
| 2 | | Invensys Systems Incorporated | |
| 2 | | Invensys Systems Inc. | |
| 1 | | Invensys Systems, Inc | |
| 1 | | Invensys Systems, Inc. | |
| 1 | | ITT | |
| 1 | | ITT Corp. | |
| 26 | | Joy Mining Machinery | |
| 1 | | Joy Mining Machinery | |
| 1 | | Joy Mining Machinery Ltd | |
| 1 | | K-Tek Corporation | |
| 5 | | K-Tek Corp. | |
| 2 | | Kistler Instrument Corp | |
| 6 | | Kistler Instrument Corporation | |
| 1 | | Knappco Civacon | |
| 1 | | KOEHLER-BRIGHT STAR | |
| 1 | | KOEHLER – BRIGHT STAR, Inc. | |
| 1 | | Lectrodryer LLC | |
| 1 | | Magnetrol International Inc. | |
| 1 | | Matric Limited | |
| 1 | | Micro Motion | |
| 2 | | Micro Motion Inc. | |
| 4 | | Micro Motion, Inc. | |
| 2 | | Mine Safety Appliances | |
| 5 | | Mine Safety Appliances Co. | |
| 3 | | Mine Safety Appliances Co. (Instrument Division) | |
| 1 | | Moore Industries International | |
| 2 | | OPW Fuel Management Systems | |
| 1 | | Otto Communications, Div. of Otto Engineering Inc. | |
| 5 | | PARKER HANNIFIN CORPORATION | |
| 1 | | Pelco | |
| 1 | | Pelican Products Inc. | |
| 2 | | Pepperl + Fuchs Inc. | |
| 1 | | Quest Technologies, Inc. a 3M Company | |
| 2 | | RAE Systems | |
| 1 | | RAE Systems Inc | |
| 1 | | Rae Systems Inc. | |
| 1 | | Relcom Inc | |
| 1 | | Reliance Electric Company | |
| 1 | | RKI Instruments | |
| 1 | | Rockwell Automation - Allen Bradley Co. Inc | |
| 7 | | Rosemount Inc | |
| 17 | | Rosemount Incorporated | |
| 9 | | Rosemount Inc. | |
| 1 | | Scott Health & Safety, Division of Scott Technologies | |
| 1 | | Sierra Instruments Inc. | |
| 2 | | SOR Incorporated | |
| 1 | | SOR, Inc | |
| 2 | | Spectrex Ltd | |
| 1 | | Sperian Protection | |
| 1 | | Sperian Protection Instrumentation | |
| 1 | | TopWorx Inc. | |
| 2 | | TYCO THERMAL CONTROLS | |
| 15 | | Tyco Thermal Controls LLC | |
| 3 | | Veeder-Root Co. | |
| 2 | | Veeder Root Co. | |
| 1 | | VorTek Instruments, LLC | |
| 1,263 | | |