process plant

Hazardous Area Verification Dossier Compliance

Don’t be caught short – make sure your Hazardous Areas Compliance information is available and accessible.  

Author: Brad Guy 

We’ve written previously about defining and managing hazardous areas. In today’s article, we’ll talk about another critical part of hazardous areas management – the verification dossier. 

Overview and Definitions

Where a flammable atmosphere is created in an area that requires special precautions for the construction, installation and use of equipment that will prevent an explosion, the area will need to be classified into zones, gas (or dust) groups and temperature classes for the selection of equipment that can be used in that area. 

From this moment all documentation in relation to the installation needs to be available and access given to all those that work in or in relation to the hazardous areas.  This collection of documentation is referred to in AS/NZS 60079.14 as the “verification dossier”. 

AS/NZS 60079.14:2017 


3.1.2 Verification Dossier 

 set of documents showing the compliance of electrical equipment and installations 

4.2 Documentation 

It is necessary to ensure that any installation complies with the relevant equipment certificate as well as with this standard and any other requirements specific to the plant on which the installation takes place. To achieve this result, a verification dossier shall be prepared for every installation and shall be either kept on the premises or stored in another location. In the latter case, a document shall be left on the premises indicating who the owner or owners are and where that information is kept, so that when required, copies may be obtained. 

NOTE The verification dossier can be kept as hard copy or in electronic form. Methods accepted by legislation in each country can have an impact on the form in which the documentation will be legally accepted. 

Verification dossiers come in many different forms as the standard describes above and may be hard copy, soft copy or in App form that can be used to complete inspections using certified phones or tablets.  

Compiling of documentation for the Verification Dossier needs to start from first conception of the hazardous area as it is much easier to collect it as the project proceeds rather than try to collect it after the project is well underway or plant has been operational for some time. 

From experience we’ve observed that the Verification Dossier on many sites is not complete, varying from not existing at all, to a verification dossier that may contain outdated information or minor discrepancies. 

The AS/NZS 60079 series of standards separates the dossier into several different sections summarised below; – 


  • Area classification documents 
  • Plan showing zonal extents (including elevation gives more clarity to actual extents)   
  • Classification schedule report including: 
  • Explanation of the hazardous areas 
  • Flammable gas/vapours that form the hazardous area 
  • Gas subgroups (IIA, IIB or IIC) 
  • Temperature class or ignition temperature (T1, T2, T3, T4, T5 or T6) 
  • Combustible dusts that form the hazardous area 
  • Dust subgroups (IIIA, IIIB or IIIC) 
  • Maximum permissible dust layer thickness 
  • Material characteristics: 
  • Electrical resistivity 
  • Minimum ignition temperature of the dust cloud 
  • Minimum ignition temperature of the dust layer 
  • Minimum ignition energy of the dust cloud 
  • Eternal influences 
  • Optional assessment of consequences of ignition (Explosion Protection Levels [EPL’s]) 


  • Manufacturer’s instructions for selection, installation and initial inspection 
  • Conditions of installation for electrical equipment that has an “X” suffix on the certificate number 
  • For intrinsically safe systems a descriptive system document for the system 
  • Details of any calculations 
  • Purging and pressurisation ventilation rates 
  • Intrinsically safe calculations (see previous article on IS calculations) 
  • Power distribution calculations for Ex e installations 
  • Thermal distribution calculations for Ex d installations 
  • Conformity Assessments or Fitness for Purpose reports for equipment that does not have suitable certification (AUSEx – now superseded by ANZEx, IECEx) 
  • Overhaul and repair documentation in relation to certified electrical equipment by a certified AS/NZS 3800 (IEC 60079.19) workshop 


  • Information on equipment installation for the protection type (Ex d, Ex e, Ex i, Ex n, Ex p, Ex t etc.) 
  • Information on equipment suitability for the environment 
  • Temperature ratings 
  • Type of protection 
  • IP rating 
  • Corrosion resistance 
  • Electrical drawings including 
  • Cable schedules 
  • Wiring diagrams 
  • Electrical schematics etc. 
  • Circuit identification 
  • Details of selection criteria for glanding used for the type of protection and the environment 
  • Inspection results 
  • Initial Detailed Inspection results 
  • Previous inspection results 
  • Qualifications and competencies for all personnel for example; – 
  • HA classifier 
  • HA designer 
  • HA equipment installer 
  • HA installation inspector etc. 

Each installation will be different and there may be different requirements for information that may be required to be kept in the verification dossier. 

The recommendations above are set out in AS/NZS 60079.14 and AS/NZS 60079.17 to use relevant points mentioned above as a minimum, with the variation in plant size, and type, the verification dossier can end up being quite large. 

There may already be information and systems in place that cover certain requirements for the dossier. In these cases, it’s important to note that the information does not need to be duplicated.  Likewise, information included in the verification dossier does not need to be kept together in one location or system. It simply needs to be accessible to those that require it. 

One of those that may require access to the dossier is the Electrical Safety Office as they perform random audits. (See our previous article on random ESO audits here) 

In conclusion, the verification dossier may be kept in several different places and forms, it is a live document that needs to be current at any point in time, it needs to be accessible to all that require information in relation to the hazardous areas.