| 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 | |
| 7 | | ABTECH Limited | |
| 1 | | Advanced Sensors Ltd | |
| 1 | | Alpha Moisture Systems | |
| 1 | | AnTech Limited | |
| 2 | | Ashridge Engineering Limited | |
| 10 | | ATB Laurence Scott Limited | |
| 5 | | ATB Morley Limited | |
| 2 | | ATB Morley Ltd | |
| 2 | | Authentix Limited | |
| 1 | | Baldwin and Francis Ltd | |
| 13 | | BEKA Associates Limited | |
| 1 | | Bifold Fluid Power | |
| 3 | | Bifold Fluidpower Limited | |
| 2 | | Cable Management Products Limited | |
| 1 | | Cameron | |
| 1 | | Capcis Limited | |
| 2 | | Chalmit Lighting | |
| 14 | | CMP Products Limited | |
| 1 | | Conflow Ltd | |
| 2 | | Controlled Systems Limited | |
| 5 | | Cooper MEDC Limited | |
| 1 | | Crowcon Detection Instruments Limited | |
| 8 | | Crowcon Detection Instruments Ltd | |
| 1 | | Daniamant Ltd | |
| 1 | | David McClure Limited | |
| 1 | | David McClure Ltd | |
| 1 | | Davis Derby Limited | |
| 2 | | Davis Derby Ltd | |
| 1 | | Detectronic Limited | |
| 6 | | Don Electronics Limited | |
| 2 | | Draeger Safety UK Ltd | |
| 4 | | Druck Limited | |
| 2 | | e2v Technologies (UK) Limited | |
| 1 | | e2v Technologies (UK) Ltd | |
| 1 | | Eltron Chromalox | |
| 1 | | European Safety Systems | |
| 1 | | European Safety Systems Limited | |
| 3 | | European Safety Systems Ltd | |
| 3 | | Expo Technologies Ltd | |
| 1 | | Extronics Limited | |
| 2 | | Gai-Tronics (A Division of Hubbell Limited) | |
| 1 | | Gai-Tronics (A Division of Hubbell Ltd) | |
| 3 | | Gas Measurement Instruments Limited | |
| 1 | | Gas Measurement Instruments Ltd | |
| 1 | | GDS Technologies Limited | |
| 3 | | Golder Associates (UK) Ltd | |
| 1 | | H & B Sensors Limited | |
| 1 | | Hadar Lighting | |
| 2 | | Hadar Lighting Ltd | |
| 5 | | Hansford Sensors Limited | |
| 1 | | Hansford Sensors Ltd | |
| 24 | | Hawke International | |
| 3 | | Hohner Automation | |
| 4 | | Honeywell Analytics Limited | |
| 1 | | Honeywell Anakytics Limited | |
| 2 | | Honeywell Analytics | |
| 3 | | Honeywell Analytics Limited | |
| 2 | | Honeywell Analytics Ltd | |
| 2 | | Hydramotion Limited | |
| 1 | | Imtex Controls | |
| 2 | | Imtex Controls Limited | |
| 1 | | Intecpc Limited | |
| 1 | | Intecpc Limited | |
| 1 | | Ion Science Limited | |
| 2 | | ITT Flow Control Ltd | |
| 1 | | ITT Flow Control Ltd. | |
| 2 | | John Crane UK Limited | |
| 1 | | Joy Mining Machinery Ltd | |
| 4 | | KAC Alarm Company Limited | |
| 1 | | Kinetrol Limited | |
| 1 | | Kingspan Environmental Ltd | |
| 5 | | K&TC Manufacturing Limited | |
| 3 | | LMK Thermosafe Limited | |
| 3 | | Measurement Technology Limited | |
| 73 | | Measurement Technology Limited | |
| 1 | | Measurement Technology Limited | |
| 1 | | Michell Instruments Limited | |
| 10 | | Mobrey Limited | |
| 3 | | Monitran Limited | |
| 5 | | Newson Gale | |
| 5 | | Newson Gale Limited | |
| 1 | | Parson Peebles Generation Limited | |
| 1 | | PCME Limited | |
| 1 | | Peppers Cable Glands Limited | |
| 1 | | Perpetuum Limited | |
| 1 | | Pipelines 2 Data | |
| 1 | | Pressure Tech Limited | |
| 1 | | Pyroban Limited | |
| 2 | | Qinetiq Limited | |
| 6 | | Raxton Limited | |
| 2 | | Redapt Engineering Co Ltd | |
| 1 | | Redapt Limited | |
| 2 | | Rockwell Automation Limited | |
| 3 | | Rota Engineering Limited | |
| 6 | | Rotork Controls Limited | |
| 1 | | Rotork Skilmatic | |
| 1 | | Servomex Group Limited | |
| 2 | | Servomex Limited | |
| 1 | | Shaw Moisture Meters | |
| 1 | | Signature Industries Limited | |
| 1 | | SKF (U.K.) Limited, Condition Monitoring Centre (Livingston) | |
| 1 | | Specac Limited | |
| 1 | | Talentum Developments Limited | |
| 6 | | Technolog Limited | |
| 1 | | Thompson Valves | |
| 1 | | Thorn Security Ltd, T/A Tyco Safety Products | |
| 2 | | Tracerco | |
| 3 | | Trolex Limited | |
| 1 | | TrueRead Limited | |
| 1 | | Tyco Valves and Control Ltd. | |
| 1 | | TYCO Valves and Controls | |
| 2 | | Tyco Valves and Controls | |
| 1 | | Tyco Valves & Control Limited | |
| 1 | | T.E.L Engineering Limited also trading as Trolex Engineering | |
| 3 | | Victor Products Limited | |
| 17 | | Walsall Limited | |
| 1 | | Walsall Ltd | |
| 1 | | Westlock Controls Limited | |
| 2 | | Westlock Controls Limited | |
| 1 | | Westlock Controls Ltd | |
| 1 | | Westlock Controls Ltd. | |
| 2 | | Weston Aerospace Limited | |
| 1 | | Wolf Safety Lamp Company Limited | |
| 2 | | Wolf Safety Lamp Company Ltd | |
| 1 | | Wolf Safety Lamp Co. Ltd | |
| 1 | | Wymark Limited | |
| 272 | United States of America | |
| 1,489 | | |