Machine safety: What is ambient air temperature and the relationship to safe operation?

How can the ambient air temperature range from -30 to +120 degrees Fahrenheit inside a manufacturing plant? The product specs call for certification at -5 to +30 degrees Centigrade for safe operation. Do the international machine safety standards address this?


How can the ambient air temperature range from -30 to +120 degrees Fahrenheit inside a manufacturing plant? The product specifications call for certification at -5 to +30 degrees Centigrade for safe operation. How do we accommodate an ambient air temperature range like that? Do the international machine safety standards address this issue?

You know what I say – welcome to the big league!

First of all, is there a common global definition and application for the word ambient air? Think about different locations around the world for manufacturing plants. Phoenix, Arizona? Puebla, Mexico? Xilin, China? Belo Horizonte, Brazil? Riyadh, Saudi Arabia? Innsbruch, Austria? Rotterdam, Netherlands? Is there anything common about ambient air in all of these locations?


I’ve been to a manufacturer in Xilin, China. The large plant had big wide doors that were open all year long. The ambient air (in my definition) was 18 degrees Fahrenheit while I stood by a CNC controlled machine with color graphic HMI operator panels. I was told that the ambient air in July and August often exceeded 120 degrees Fahrenheit. There was no heat and there was no air conditioning in the facility.


So, when a machine safety standard talks about an ambient air temperature requirement for safe operation of a machine safety control element – what does that mean? Is the ambient air temperature of concern that air which is inside of the small cabinet/box containing the safety control element? Or, is it the ambient air temperature around a machine outside of the small cabinet or box? Or, if the small cabinet or box is mounted inside of a large control cabinet is it the ambient air temperature inside of the large control cabinet? How are these questions about ambient air temperature to be interpreted and understood consistently by different languages and cultures in multiple countries? What was intended by the manufacturer of the machine safety control element?


In my opinion, having participated in several discussions around the world on this subject, decision makers really need to fully understand the product, application, and the conditions where the application will ultimately reside to determine the ambient air temperature issue. Having said that, ultimately an interpretation of the requirement stated in the international standard will have to be made. This could mean the addition of some capability to treat or control a defined ambient air temperature to meet the requirements for safe operation.


J.B. Titus, CFSE

Has this presented you with any new perspectives? Add your comments, thoughts or advice to the discussion by submitting your ideas, experiences, and challenges in the comments section below.


Related articles:

NFPA 79: Electrical Standard for Industrial Machinery, 2012 Annotated PDF Edition

IEC 62061 Safety of machinery - Functional safety of safety-related electrical, electronic and programmable electronic control systems

IEC 60204-1 Safety of machinery - Electrical equipment of machines - Part 1: General requirements

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