In Brief

  • Many of the nomenclatures used in industry standards for machines rely on seemingly simple ranking systems; however, because many of the classifications utilize alphabetical or numerical designators, confusion is common.

  • As is the case in many specific fields of study, one must first be familiar with the basic expressions that are often used in order to speak intelligently about a given topic.

  • This article is a primer for those looking for a single reference source to understand this seemingly confusing lexicon.

When OSH personnel and controls engineers collaborate with suppliers to implement protective measures for industrial equipment, the discussion can quickly get off track, as various terminologies and jargon are used, often with little to no true understanding of what the terms actually mean. Often, the only way to decipher these code words has been to track down the appropriate standard for context. This article is a primer for those looking for a single reference source to understand this seemingly confusing lexicon.

As is the case in many specific fields of study, one must first be familiar with the basic expressions that are often used to speak intelligently about a given topic, and industrial safety is no different. In the safety marketplace, safety standards are heavily relied on to present basic concepts and specific definitions to establish common ground. Many of the nomenclatures used in these standards rely on seemingly simple ranking systems; however, because many of the classifications utilize alphabetical or numerical designators (Figure 1), confusion is common.

Stratification of Safety Standards

Most safety standards aim to provide the audience (readers) with an overall framework and guidance for decisions during the entire life cycle of machinery to enable them to maintain machines that are safe for their intended use. Many standards-developing organizations use the following structure (Figure 2):

  • Type-A standards (basic safety standards) contain basic concepts, principles for design and general aspects that can be applied to machinery.

  • Type-B standards (generic safety standards) deal with one safety aspect or one type of safeguard that can be used across a wide range of machinery: a) Type-B1 standards cover particular safety aspects (e.g., safety distances, surface temperature, noise); b) Type-B2 standards cover a safeguarding device (e.g., two-hand controls, interlocking devices, pressure-sensitive devices, guards).

  • Type-C standards (machine safety standards) contain detailed safety requirements for a particular machine or group of machines.

This stratification was first developed by ISO/IEC Guide 51 and was implemented in Europe during the development of European Norms (EN) standards; these documents were then elevated to international (ISO or IEC) standards, and the interrelationships as laid out were maintained. Many organizations follow ISO/IEC Guide 51, which was updated in April 2014. As a practical application of this structure in use in North America, the ANSI B11 (2010) series of standards for machine tools has implemented a similar organization (Figure 3, p. 30).

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