ASSE Mini Tech-Brief:
Confined Spaces

Update and status of the ANSI/ASSE Z117.1-2009 Standard: Safety Requirements for Confined Spaces

As secretariat of the Z117 ANSI Accredited Standards Committee (ASC) for Confined Spaces, ASSE has continued to receive a number of inquiries related to the ANSI/ASSE Z117.1-2009 American National Standard titled: Safety Requirements for Confined Spaces.

During committee revision meetings regarding the 2003 version of the Z117.1 standard, the Z117 ASC reviewed current available data and information addressing confined space incidents, and noted that evidence suggests that the cause of death associated with confined space entry has not changed appreciably during recent years. 

According to the Z117 ASC, a review of 200 confined space fatality cases from the U.S. Department of Labor (DOL) Occupational Safety and Health Administration (OSHA) database occurring between 1993 and 2004 confirmed that the distribution of causes had not changed to any significant degree. The committee also noted that approximately 65 percent of incidents with fatalities involved atmospheric contamination and engulfment accounted for less than 10 percent of the identified causes. However, the fatality cases in this sampling do not represent all U.S. confined space incidents resulting in fatalities.

The aim of the newly revised Z117 Standard is to provide for the minimum performance requirements necessary in developing and implementing a comprehensive confined space program for the protection of workers. Click here for additional details on the revised Z117 standard.

Links and information related to the Z117.1 American National Standard:

The links below address recognition of the Z117 ASC:

The two articles below also address how standards are used by governmental agencies:



Changes to the ASSE/ANSI Z117.1 Standard - Safety Requirements for Confined Spaces


Wednesday, September 30th
11:00 AM – 12:30 PM CDT

Starting November 2nd, the new ASSE/ANSI Z117.1 standard governing confined spaces becomes effective.  This webcast is your first opportunity to obtain the standard and attend an informative session given by an expert in its content.

Interact with Terry Krug, Vice-Chairman of the Z117 Confined Spaces committee, in this special ASSE webcast.  During the session, you’ll explore the new ASSE/ANSI Z117.1 standard and look at the changes which will impact your operations.

Join us for this special webinar, which will take place on Wednesday – September 30th, from 11:00 AM – 12:30 PM central time.


There are usually numerous questions addressing the newly revised ANSI/ASSE Z117.1 Standard (Confined Spaces) and how it has been used in the past related to OSHA and the General Duty Clause.  We know this standard is used by SH&E Professionals on a consistent basis, and this is always a common question.  The link below is to a matrix which includes a collection of examples from 1999 to 2009.  You can also get this information from the OSHA stats page, but we put it together in one file.  

It is important to note these are Federal OSHA examples.  The standard is used and recognized by a wide variety of public and private sector organizations and companies at the international, national, state, and local levels. Click here for the Matrix (doc).


Confined Space Resources from ASSE:

Additional Recognition:

The Z117 ASC letter to OSHA expressing concern with chest and full body harnesses during confined space entry and the OSHA response:

Other Examples:

The links below are decisions from the Occupational Safety and Health Review Commission, which cites/references the Z117.1 Standard:

The file below includes examples of recognition by the U.S. Department of Energy over several decades: Click here fo the DOE Z117 Recognition File (doc).

An example from NASA:

An example from the United States Navy:

Links from NIOSH:

Link from Berkley National Laboratory:

An example from the U.S. Department of the Army:

An example from the U.S. Department of the Air Force:

State Examples:

International Examples:

The link below is to SafeWork Australia:

The link below is from the Australian Air Force

Thanks and regards,

Timothy R. Fisher, CSP, CHMM, ARM, CPEA
Director, Practices and Standards
American Society of Safety Engineers (ASSE) 


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