Industry News

    Richard McNitt
Post by On 23 September 2012 In CPCA Corner

Certifying Your Products for Use in Hazardous Locations

Certification of electrical equipment for use in hazardous locations has become a complex landscape of confusing options. The process can be frustrating, expensive and time-consuming.

If you keep certification in mind from the beginning of your design cycle through prototyping and final production, you can avoid many of the delays and pitfalls that occur from inadequate understanding of the required standards, thereby speeding your time to market.

If you are an end-user it is important that all products you will use in your application have the proper certifications for safe installation in hazardous areas.

Armed with knowledge and working with a trusted certification agency (there are many to choose from in Canada who are approved by Industry Canada), both manufacturers and end-users can reduce hassles from the certification process.

Why certification – and the right certification partner – is essential

Designed and constructed to reduce the risk of igniting the surrounding atmosphere, hazardous location equipment has been included in national codes and safety standards for many years. Generally, locations are regarded as hazardous when fire or explosion may result from the presence of flammable gases, vapors, liquids, combustible dust, ignitable fibers or flyings.

By getting your equipment certified, you not only meet regulatory requirements in many jurisdictions, you also build and sustain market acceptance of your brand.

Before submitting a Certification package, think about its organization. You can help make the process smooth and efficient if you prepare an enclosed table of contents and drawing list; these can be invaluable in getting the prompt attention of the certification engineer at the other end.

By making the certification process a partnership – between a well-informed and well-prepared manufacturer and a knowledgeable, resourceful certification agency, many hurdles can be avoided and equipment used in hazardous locations can be certified in an efficient and effective manner.

Step 1: Know your market and the standards that apply

If you have not designed your equipment to a standard, it likely will not comply. By understanding and reading applicable standards first, you can strip time and money from the certification process.

Where do you want to sell the equipment? Each jurisdiction has its own set of standards, but most are members of International Certification Schemes. This means that, in general, you will have a choice of complying with specific country or regional standard(s), or internationally harmonized standard(s).

Most countries will have their own “National Deviations” to the internationally harmonized standards; these are mainly limited to those that accommodate local installation codes and regulations.

Canada CSA Standards; C22.2 Series, and/or CAN/CSA C22.2 Series (based on IEC with National Deviations)
USA ANSI∖XX, where XX is the symbol of the standard writer (ISA, FM, UL, etc.), and/or ANSI standards based on IEC, with National Deviations
EU EN Series Standards, based on IEC with National Deviations
Australia IECEx Scheme Certificate = IEC Standards without Deviations
Far East IEC based Standards with National Deviations
ROTW In general, the rest of the world uses IEC based Standards with Deviations

Whether you choose to comply with regional or international standards depends on whether you intend to sell your product in one, or a limited number of specific markets; or whether you intend to sell your products globally. From Table 1.1, you can see that all major markets, as well as most of the rest of the world (ROTW), uses some type of IEC based Standards with National Deviations.

For North America, in addition to Hazardous Locations Standards, your equipment must comply with the applicable Ordinary Locations Standards.

No matter where you want to market, regionally or globally, you will have to determine the method(s) of ignition protection you will utilize. This depends on where the equipment will operate, the equipment’s ratings and use, and other design considerations. There are numerous websites and publications that detail the different methods of protection, and the standard(s) applicable to each.

Once you know which standards apply to your markets, be sure to obtain, read, understand and incorporate their requirements into your product design. A few standards are provided free of charge by some certification agencies; others are offered for sale by certification agencies, standards writing organizations, national accreditors, technical bookstores, and other sources. Most technical libraries, universities, colleges and trade schools also maintain a collection of certification standards.

Tests

The Tests section of the standard(s) should be reviewed, not only to ensure prototype equipment will be able to pass, but also to get an idea of the sample requirements. You don’t want sample requests to come as a complete surprise later on.

Markings

One of the most important sections to review is the Markings section. A drawing of the nameplate(s) will be required that includes information (nameplate material, dimensions, markings, marking method, adhesive nameplate manufacturer and catalogue number, etc.) for each unique model, configuration, ratings, etc.

To indicate the approval for the Canadian market, a capital C is placed right before the logo of the Certification Body (CB), and a US indicates the approval for the United States. A directory of SCC-accredited CB’s can be found on the SCC website (www.scc.ca) under “Accreditation”.

The exact method of marking must be stated. For hazardous locations equipment, markings must be permanent, such as engraved or etched to the surface of the equipment, or printed or etched onto a metal nameplate secured to the equipment. If an adhesive label is used, it must be approved by the appropriate certification agency.

Step 2: Apply the standards to your products

Standards requirements don’t find their way into products by osmosis. The time you spend on understanding requirements to the point where they can be translated into product design (and to Certification Drawings) will be well-rewarded.

In most cases, requirements are reasonably straightforward, asking you to ensure your equipment meets them. There may be other instances where a requirement is subject to interpretation, as it relates to your equipment. In these cases, it is important to find the right answer rather than to just guess at it.

Most certification agencies will have some mechanism for answering technical questions. For this service, it is best to ask questions that can be answered Yes/No, or with a short explanation.

For more detailed questions, you may need to initiate a project with a certification agency. Most offer some type of Technical Information Service to review designs and answer standard-related questions. This can be a great upfront investment, providing valuable information that can help save time and possible mistakes further down the road.

Step 3: Gather and submit product information

Once you are ready to proceed with certification, the agency will require certain information to begin your project:

What exactly do you want to certify? Be sure to define:

  • the Series / Catalogue / Type / Model / Other Designation code(s), complete with all suffixes (as it/they will appear on the equipment nameplate)
  • the complete electrical ratings (V, A, Hz, HP, etc) for each Series/Type/Model to be included in the Certification

There are many cases where the certification will include a series of products with many different configurations and/or optional accessories. Some or all of the ratings will be dependent on the specific model within the series. In these cases, it will be necessary to summarize all “series”, “models” and/or suffixes, and their complete meanings. It may be necessary to have a table or model nomenclature guide.

Depending on the certification, other applicable ratings may need to be included, such as Enclosure Ratings, Process Pressure and Process Temperature, the words “Dual Seal” or “Single Seal,” reference to an installation drawing, and other warnings, cautions or explanatory notes as required by the standard(s) or to clarify the extent of the certification.

Step 4: Your agency’s certification report

Knowing what to expect from a certification report can help you collect all relevant product information for your certification agency and prepare for the certification process.

The purpose of a certification report is to show objective evidence of compliance with the applicable standards. Actually, the report provides a summary; the actual evidence is the original test data and evaluation records which are retained by certification agencies for the project.

In North America, Certification Reports are also used as a reference during required follow-up audits of equipment from production.

The main sections of a Certification Report cover:

  • Identification of Product – see Step 3 above
  • Hazardous Locations designation – sometimes included as part of Description of Product, or under Markings
  • Applicable Requirements – the standard(s) used to evaluate the equipment
  • Markings – required equipment markings and warnings (see Markings above)
  • Description of Equipment – functional and constructional description; may include manufacturing or construction drawings (or drawing list).
  • Certification Drawings – prepared by the manufacturer, giving a full and correct specification of the explosion safety aspects of the electrical equipment (see Drawings below)
  • Test Section – summary of the testing, test conditions and results

The most time-consuming part of a Certification Report is the Description of Equipment, especially the Constructional Description, and this is where the manufacturer can help save time and money during the project. You know your equipment, and can probably produce a constructional description of the equipment more expediently than the certification agency.

Description of Equipment

This section is central to any Certification Report, filling two main functions:

  • documenting for the manufacturer (and certification agency) the details of the exact construction which is required in order for the product to bear the appropriate mark, and;
  • showing (or summarizing) compliance of the constructional aspects of the product to the requirements of the applicable standard(s). In some cases, it may also show compliance with test requirements.

As a guideline, the project file should contain sufficient information that the product could be constructed. That means for “certified” components, the manufacturer, model and ratings; for printed circuit board’s, board and trace layouts; for enclosures, casting/machining drawings; etc. Not all of this information will be included in the Certification Report, but it should be in the project file.

Normally, there are two sections within the Description:

  • The General section contains a brief (1-2 sentences) general description of the equipment. This may include the function of the equipment, the general application, where/how the equipment is mounted, how the user connects electrical power and signal wiring, or other pertinent details. This section may also include a model nomenclature guide and complete details of “Series”, “Types” and/or “Models”, including all suffixes, options, accessories, etc., as well as a description/explanation of all “Model-dependent” ratings.
  • The Construction section details the specifics of construction of the product. You can accomplish this in two ways:
    1. A basic report referring to the manufacturer’s drawings identifying which drawings show compliance to which requirements. In most cases, regular “manufacturing drawings” will not have sufficient information, and specialized “Certification Drawings” (see below) must be produced by informed manufacturers, showing critical safety-related components, dimensions, specifications, etc., clearly identified, for the full range of models, options, accessories, etc.
    2. A more detailed report, where the critical safety-related components, dimensions, specifications, etc. for all models, are described in the text of the Report. This is more difficult and time-consuming to write, as each requirement must be addressed and objective evidence of compliance provided (or summarized and retained in Engineering files). In this case, your drawings are referenced as a description of the construction of the equipment, but not as evidence of compliance to the constructional aspects of the applicable standard(s).

No matter which style of Report, care must be exercised when including manufacturers’ drawings (or drawing list) in the Certification Report. When you include a drawing, you include everything on that drawing unless it is specifically excluded in either the Report or drawing notes.

Certification Drawings

The Certification Drawing is a summary of all constructional requirements of the applicable standards, and verifies that the equipment complies; or at least that the manufacturer is aware of the requirements.

A Certification Drawing is not the same thing as a construction or manufacturing drawing. It must be prepared to comply with IEC 60079-0, General Requirements Clause 24 - Documentation, “The manufacturer shall prepare documents that give a full and correct specification of the explosion safety aspects of the electrical equipment.”

Ideally, the Certification Drawing(s) should show how the equipment complies with each constructional requirement contained within the applicable Standards used for evaluation. If the Standard requires a 25-mm length and a 0.010-mm gap, the Certification drawing should contain this information adjacent to the joint. If the Standard requires a minimum separation of 0.5-mm, the Certification drawing should note that for all traces, a minimum of 0.5-mm separation shall be maintained. In North America these requirements must be translated to the appropriate Manufacturing Drawings.

In North America, certification agencies still require Manufacturing Drawings. These must document, for the manufacturer (and the certification agency), the details of the exact construction required for the product to bear the appropriate mark.

Read 156796 times Last modified on Monday, 16 June 2014 15:05
  Richard McNitt

Business Development Manager, Hazardous Locations
CSA Group

www.csagroup.org

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