The digitalization of maintenance is continuously progressing. Digital maintenance plans, mobile documentation, QR codes, and ERP connections make smartphones and tablets indispensable tools in the process industry today.
With the new AK practice of the NAMUR working group 4.7 Explosion Protection a frequently discussed topic is now specified: Under what conditions may ATEX devices of category 3 (Zone 2/22) be used temporarily in areas of Zone 1 or 21 during maintenance work?Important in advance: No general approval for Zone 1 eingesetzt werden?
The most important statement of the new AK practice is:
The publication does not constitute a general approval of category 3 devices for Zone 1 or Zone 21.
On the contrary:
If suitable category 2 devices for Zone 1/21 are available, they should generally be preferred.
If suitable devices of category 2 are available for zone 1/21, they should generally be used preferentially.
The NAMUR only describes a possible explosion protection concept that can be applied within the framework of a company risk assessment. It is not a change to the ATEX directive or the zoning.
Why is this topic even being discussed?
In many companies, a practical problem arises:
Modern smartphones and tablets of Category 2 (Zone 1/21) often do not offer the same performance as current consumer or industrial devices of Category 3 (Zone 2/22). Reasons include:
outdated operating systems
limited hardware
limited device selection
lack of support for modern enterprise software
The selection of powerful devices in category 3, on the other hand, is significantly larger. This led to the question of whether such devices can also be used for maintenance activities under certain conditions.
The restrictions are crucial
The NAMUR clearly states that category 3 devices may only be carried in Zone 1/21 temporarily under strictly defined conditions.
These include, among others:
exclusively for maintenance activities
no permanent stay in the Ex area
no unattended storage
immediate evacuation of the area in case of gas alarm, solvent smell, or dust emission
no charging or opening of the device in the Ex area
no use of USB or other interfaces
Protection against falling
Removal of the device after a fall until inspection
documented risk assessment
Operating instructions and training of employees
Especially important: The ban remains in place for activities with foreseeable explosive atmospheres
This point is often overlooked.
NAMUR explicitly states:
Category 3 devices must not be used in work where the occurrence of an explosive atmosphere is to be expected.
This includes, for example:
Sampling
Discharge and transfer processes
Dosing through manholes
Filter changes
Cleaning work with possible substance release
For such activities, a device that is approved for Zone 1/21 (Category 2) is still required.
What technical requirements apply?
Even when using Category 3 devices, the AK practice specifies minimum requirements:
ATEX Category 3 according to Directive 2014/34/EU
Explosion group IIC
Temperature class T4
Dust group IIIB
Protection class at least IP54
Additionally, the devices must be documented, tested, and released by the operator.
What does this mean for operators?
The new AK practice offers companies more flexibility in the digitalization of maintenance.
However, it does not replace any risk assessment. and no legal requirements.
Each operator must assess individually,
whether the described boundary conditions are met,
what organizational measures are necessary,
and which work is permissible with category-3 devices.
Our recommendation from ATEXshop
The publication from NAMUR shows that modern mobile working tools can increasingly become part of safe maintenance processes.
Nevertheless, the following still applies:
For regular use in Zone 1 or Zone 21 we generally recommend ATEX-certified devices of category 2.
Category-3 devices can only be used within the framework of the explosion protection concept described by NAMUR and a documented risk assessment.
A blanket approval for Zone 1 or 21 does not exist.nicht.
Anyone wishing to use smartphones or tablets in explosion-hazardous areas should therefore not only pay attention to the choice of devices but also consider the organizational requirements and the operational documentation.
Do you have questions about selecting suitable ATEX smartphones or tablets? The team from ATEXshop.deis happy to assist you in selecting a compliant and practical solution for your area of application.