Are IECEx unit verification certificates for Ex equipment assemblies a good option for the Australian hazardous area market? Maybe.

What is an IECEx Unit Verification?

For normal electrical equipment certified under the IECEx scheme the manufacturer must produce a piece of equipment that is designed and tested to the required IEC 60079 standards and must also have a Manufacturing Quality Management System (QMS) in place to ensure the consistency and quality of the equipment they are manufacturing under the IECEx certificate. This makes sense because the end user would like to know that the equipment they are purchasing meets the required standards and that the manufacturer will continue to produce the equipment after the initial certification to the applicable standards and quality benchmarks hence the need to for a QMS.

But what happens if the manufacturer or end user does not want to build multiple units in a continuous production run, they only want to build a single unit or a handful of units under a single production run. In this case it may not be suitable to require the manufacturer to implement a Manufacturing Quality Management System (QMS) because the IECEx Certified Body (Ex CB) can assess the single unit or single production run and manage the quality assurance for the unit or single production run on a case-by-case basis.

To fill this gap, the IECEx introduced an IECEx certificate that covers a defined number of products/items that are produced under a single production run. This form of certificate is known as an IECEx unit verification. The unit verification has a handful of unique features that make it different to a standard IECEx certificate of conformity (CoC) that are worth noting:

1. The IECEx unit verification certificate can only be issued for a defined number of items under a single production run.
2. The IECEx unit verification certificate has largely the same format as the existing CoCs but it also lists the serial numbers or other unique identification of the specific equipment it applies to.
3. For the IECEx Unit Verification to be issued it must also be supported by a full and complete Ex Test Report (Ex TR). And the equipment must meet the full requirements of Standards applied.
4. No Quality Assessment or ISO 9001 certification is required or verified at the time of issuing an IECEx Unit Verification Certificate.
5. The CoC includes “Unit Verification” Text for the QAR field of the Certificate.
6. New issues of issued Unit Verification CoCs are not permitted.
7. Unit Verification may cover repaired items but does not address the repair process.

What Sort of Things Normally Get an IECEx Unit Verification?

Common equipment or assemblies that often get IECEx Unit Verification include:
1. Pressurised Rooms
2. Compressor Skids
3. Generator Packages
4. Hydrogen Electrolysers
5. Unique Specialised Assemblies
6. Heater Packages
7. Complex Control Cabinets
8. Gas Analysers
9. Custom or Single Run Electrical Equipment

So is IECEx Unit Verification Certified Equipment A Good Option for your Australian Site?

Yes and no, as with any of these discussions the devil is in the detail and there are lots of good options as long as the limitations and pitfalls are understood before any big (and usually expensive decisions are made). There are plenty of times particularly in the case of unique and specialised pieces of electrical equipment where an IECEx unit verification certificate is a good option such as a one-off custom moisture sensor for example. However, additional issues begin to arise when we move away from unit verification certificates for equipment and begin to apply unit verification certificates to equipment assemblies containing multiple pieces of already certified equipment.

What are Assembly Certificates?
An assembly certificate is a document that conveys the assurance of the conformity of an equipment assembly with specified requirements, these requirements are covered under IEC TS 60079-46.

IEC TS 60079-46 TECHNICAL SPECIFICATION Explosive atmospheres – Part 46: Equipment assemblies is the IEC technical specification that is applied when the assembly of Ex Equipment results in an assembly that creates a need for additional assessment that is not already completely covered by the individual equipment certificates. As an example, imagine a situation where a supplier manufactures a skid by wiring and interconnecting already certified IECEx equipment. In this case additional assessment would be required and can include (but is not limited to) evaluation of the total heat rise of the assembly, interconnecting wiring methods, glanding, terminations and other installation techniques used to connect the equipment.

IEC TS 60079-46 provides the requirements for the design, construction, assembly, testing, inspection, marking, documenting and assessment of equipment assemblies such that the items of Ex Equipment and the interconnection of the items of equipment form an assembly that also meets other parts of the ISO 80079 and IEC 60079 series. It’s important to note that IEC TS 60079-46 would not be applied to equipment which is covered, in its entirety, by one or more IEC 60079 and ISO 80079 equipment types of protection, or to pressurised rooms, “p”, in accordance with IEC 60079-13, artificial ventilation for the protection of analyser(s) houses in accordance with IEC TR 60079-16, and other standards addressing specific Ex assemblies;

So why does it get more complicated for big packages and equipment assemblies such as hydrogen electrolysers or compressor packages? 

There are a handful of elements that must be considered when purchasing equipment assemblies covered by an IECEx Certificate for the Australian market. Often unit verification for equipment assemblies seems like a simpler and cheaper option to ensure compliance of complex packages and assemblies because the supplier/OEM is required to get the package or assembly IECEx certified before shipping, and because Australia accepts IECEx certificates it should all be fine to connect a supply to the equipment on arrival with limited additional hazardous area compliance work required. But it’s not that simple and may not be worth the effort, or additional cost to pay an IECEx Certified Body (IECEx CB) to supply a unit verification certificate in this case because of some of the requirements detailed in AS/NZS 60079.14. Here are three things to consider in any decisions about the IECEx certification of equipment assemblies headed for Australia:

1. The IEC Operations Document OD 33 in section 2 states: “As Unit verification certificates covers specific items, any changes to products covered by an IECEx Unit Verification Certificate, that are not already provided for by the certificate, eg additional cable / conduit entries, shall require the issuing of new Unit Verification Certificate. In such situations, it is recommended that the owner of the equipment, seeking product changes consults the equipment manufacturer, prior to undertaking any such modification.”  This can introduce complications when design changes are required after the assembly has been certified, or in cases when identical spare and replacement components cannot be found to repair the equipment during routine maintenance

2. Certificates for assemblies that are made up of a number of items of certified equipment or components are often issued under the IECEx scheme by an IECEx Certified Body. In Australia under AS/NZS 60079.14 a certificate for this type of assembly is considered as valid only for the initial installation of the assembly on-site. After it is installed the assembly certificate is often considered as non-binding and the assembly needs to be managed as part of the site installation. Because of this the introduction of an assembly to site must be treated as a site installation and is therefore subject to any regulatory inspections or other requirements for site installations of normal ex equipment.

3. The IEC 60079 standards differ from the AS/NZS 60079 standards because the AS/NZS versions are modified to take into account Australian/New Zealand conditions. As a result, a certificate under the IECEx or ANZEx scheme for an assembly made up of more than one item of electrical equipment is not accepted for use in Australia unless one of the following additional steps are taken:

a. The certificate is validated as including the requirements of the latest edition of AS/NZS 60079.14, or
b. The assembly is independently inspected in accordance with AS/NZS 60079.14 for conformity.

In addition to points a) or b) above, each individual item of equipment used on the assembly must meet the requirements of AS/NZS 60079.14 relating to documentation and inspection. The practical implications for this are that once the assembly is installed it must be treated as a site installation as the assembly certificate at that stage is likely non-binding. This means the normal compliance requirements listed in AS/NZS 60079.14 will likely apply. For this reason, it often makes more sense to save the money spent paying an IECEx CB to validate the equipment assembly and issue a certificate and instead spend the time, effort and money ensuring the manufacturer builds the equipment assembly to AS/NZS 60079.14 as this will be the standard applied as soon as the equipment is installed. This article is not suggesting that equipment assembly certificates don’t have a place in the Australian hazardous area market, it is simply to suggest that their utility is limited and, in many cases the money if often better spent ensuring the equipment assemblies are built to AS/NZS 60079.14 right from the start because once installed, the assembly certificate is usually considered as non-binding.

“This following information represents and opinion only of a general nature, the specifics of each individual situation must be taken into account with reference to the relevant Legislation, Codes of Practice and Australian Standards. Lithium Oil and Gas should be contacted for professional advice if there is any doubt.”