2. Operational Technology (OT)

2.2.8 Machine certifications

There are several standards of machine certifications. Here we describe the most important ones and how they are differentiated.


It is highly probable that machines or workstations on your production shop floor have a sticker or a symbol reading CE, UL, ATEX etc. Have you wondered what those symbols actually mean?

These acronyms represent standards that guarantee safe procedures for some or all the lifecycle of a machine or workstation, which means it fulfills certain requirements in design, installation, operation, maintenance and disposal (environmental aspects) of the equipment. In the following article we describe some of the most common and important certifications.


Directive 2006/42/EC is a mandatory certification required for machine manufacturers and distributors for their product to be commercialized in the European Union. While the mark is not officially a certification as there is no requirement for follow-up testing by an overseeing organization for all product types. However, the mark is required for sale in the European Union for the specified products and labeling a non-compliant product with the mark is illegal. While the CЄ mark is relevant for a great deal of products, such as all electrical devices, toys or food safe equipment, we only focus on shop floor machines in this article.

In the first steps of the CE directive, it distinguishes the equipment as dangerous or non-dangerous. For the first category, a third party is needed to certify the machine. An example for these entities is the TÜV SÜD. For the second category the proper OEM can do the certification by creating the proper documentation of production and testing.

Aspects considered in the mark:

  • Evaluation of the general usage risk
  • Safety measurements taken for risk reduction
  • Risk due to hazardous materials in the machine or processed by the machine
  • Structural calculations
  • Low voltage analysis
  • Level of electrical and electromagnetic hazard
  • And many others

Whenever these standards are fulfilled, the manufacturer can mark the equipment with the symbol. The symbol stands for “Conformité Européenne” which means “European conformity” in French. When the manufacturer sells a machine, it must be accompanied by the declaration of conformity signed.

ANSI B11 Safety of Machinery

In the United States of America there are no mandatory regulations that forces the OEMs or distributors to certify their machines or workstations. Nevertheless, the American National Standards Institute (ANSI) created the ANSI B11.0-2020 regulation and is highly recommended for companies to demand this to machine manufacturers. Similar in scope to the previous directive in content, the ANSI B11 establishes requirements for design, construction, reconstruction, modification, installation, setup, operation and maintenance of machinery or machine systems.

Based on the ISO Type A-B-C structure for machinery standards, ANSI B11 uses the following framework for risk assessment and risk reduction:

  • Type-A standards: basic safety standards.

Concepts, design principles, and general aspects that are applicable to machinery, e.g. risk assessment based on ANSI B11-2008, determining the high, medium, low and negligible risk of an event to happen.

  • Type-B standards: generic safety standards.

Deals with single safety aspects which can be applied across a wide range of machinery. One example would be warnings of temperature of surfaces.

  • Type-C standards: machine safety standards.

Detailed standards based on the type of machine. An example is the ISO 10218-1:2011 that considers safety of robots and robotic devices in particular.

Similar to the CЄ, organizations can provide services for certifying machines. A relevant and highly recognized company in the USA is UL Solutions. Generally they provide a mark in order to demonstrate that a machine or workstation has fulfilled the requirements of a particular standard.

Certifications from companies

Large corporates with plenty of experience in manufacturing processes can have extended checklists with safety requirements while also demanding particular hardware components. Bosch Production System is an example of the biggest automotive Supplier.

Good to know - important classifications and organizations

NEMA: An ANSI-accredited standards developing organization. Defines NEMA electrical enclosures(from the control cabinets) types:

  • NEMA 1: General Purpose - indoor
  • NEMA 2: Drip-proof-indoor
  • NEMA 3: Dust-tight, rain-tight, sleet-tight outdoor
  • NEMA 4: Water-tight, dust-tight, sleet resistant-indoor & outdoor

IEC Enclosure Classification Designation

  • IP 10: Protected against solid objects up to 50mm, e.g., accidental touch by hands.
  • IP 11: Protected against solid objects up to 50mm, e.g., accidental touch by hands. Protection against vertically falling drops of water e.g., condensation.
  • IP 54: Protected against dust limited ingress (no harmful deposit). Protection against water sprayed from all directions, limited ingress permitted.
  • IP 56: Protected against dust limited ingress (no harmful deposit).

ATEX Zones: ATEX stands for Atmosphere Explosive and is a term used for the European Union 94/9/EC directive. Distinguishes between two types of explosive atmospheres: gas and dust. Although the zones characteristics are identical for both gas and dust, their numbering is different. Zone 0, 1 and 2 refer to gas and Zone 20, 21 and 22 refer to dust.

  • Zone 0 / 20: Constant danger. Permanent presence of explosive gasses or combustive dust.
  • Zone 1 / 21: Potential danger. Occasional presence of explosive gasses or combustible dust during normal duty.
  • Zone 2 / 22: Minor danger. Presence of explosive gasses or combustible dust is not likely to occur or only for a shorter period of time.

Other relevant organizations for the US market:

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