What is the real benefit of Zone 0 certification?

In many hazardous locations there is a need to use condition monitoring equipment, e.g. for measuring the vibration levels and temperatures of rotating machinery to diagnose faults such as misalignment, unbalance or impending bearing failure. The equipment needed to do the monitoring must therefore be “intrinsically safe” and incapable of igniting an explosive atmosphere.

The Dangerous Substances and Explosive Atmospheres Regulations (DSEAR) require employers to control the risks to safety from fire and explosions. Consequently, this entails compliance with BS EN 1127 (Explosive atmospheres - explosion prevention and protection), which requires that any electrical equipment used is intrinsically safe and complies with IEC 60079.

The likelihood of an explosive atmosphere existing is dealt with in these standards by the definition of various “zones”. These range from Zone 0, where an explosive atmosphere is likely to be present most of the time, to Zone 2, where it is not likely to occur in normal operation but, if it does occur, will persist for a short period only. With Zone 1 the “grey area” in between these two extremes.


Importantly, it is the responsibility of the plant operator to decide which parts of their plant are in which zones. But this can pose something of a problem. For example, these days there are many Zone 2 certified devices available, such as mobile phones or tablet PCs in special casings. These are fine when used in an area that is clearly Zone 2. But what if someone left a door or a hatch open to a Zone 0 area? Does our Zone 2 now become Zone 1, or worse still Zone 0? Does our previously certified safe, Zone 2 device now constitute a potential hazard?

This is where the real benefit of Zone 0 certification comes in. Basically, you don’t have to think because Zone 0 devices can literally be used anywhere!

There is a price to pay however, as Zone 0 devices are typically more expensive due to increased manufacturing costs (e.g. additional safety components and higher levels of redundancy). However, Test Products International (TPI) believes it has achieved a significant Zone 0 cost breakthrough with the very affordable TPI 9085Ex vibration analyser.

Costing from as little as £4,250 the TPI 9085Ex combines on-meter diagnostics with the all-important ability to TREND readings over time to simplify condition-based maintenance (CBM). Certified for Zone 0 with IECEx, ATEX and North American approval, the TPI 9085Ex can be used in ANY hazardous location anywhere in the world.

The TPI 9085Ex offers on-meter analysis for the detection of machine faults such as unbalance, misalignment, looseness and bearing wear. With full colour OLED display and Bluetooth communications, the TPI 9085Ex features colour coded alarms and zoomable on-screen vibration frequency plots with cursor readout. It can store lists (routes) of up to 1000 machines, each with up to 10 measurement points, with full waveform and frequency spectrum (FFT) capture and transfer to PC-based software.

Additionally, the TPI 9085Ex with its uniquely designed sensor, SIMULTANEOUSLY captures both VIBRATION and TEMPERATURE readings. So, if the indicated level of bearing wear is high and it’s hot then you can be sure that what you have is a worn bearing and not for example pump cavitation.

The included C-Trend PC-based trending and reporting software features all the high-end benefits, such as automatic email notification of alarms and report generation, to implement a full CBM strategy.  Routes and readings can also be transferred to/from the TPI 9085Ex via Bluetooth using a smart phone or tablet running the free TPI Cloud Bridge App. This allows service personnel to be sent routes and return readings over the Internet, no matter where they are in the world. 

For more information please contact TPI Europe’s head office on +44 1293 530196 or take a look on the website at or email This email address is being protected from spambots. You need JavaScript enabled to view it.


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