ANSI/ASSP Z117.1-2022: Entering Confined Spaces

Welding in blue confined space of a pipeline safely with ANSI/ASSP Z117.1-2022 performance requirements.

About 12.5% of all people have claustrophobia, and this fear of tight spaces can be triggered in a variety of environments. In industry, it’s more than an anxiety—confined spaces can be hazardous and even deadly. An American National Standard, ANSI/ASSP Z117.1-2022: Safety Requirements For Entering Confined Spaces, helps to protect the safety and health of employees in contact with confined spaces.

What Are Confined Spaces?

According to ANSI/ASSP Z117.1-2022, a confined space is an:

“Enclosed area large enough and configured to allow a person to bodily enter and has the following characteristics:

  • Its primary function is other than human occupancy.
  • Has restricted entry and exit.”

ANSI/ASSP Z117.1-2022 gives examples of confined spaces, including tanks, silos, vessels, pits, sewers, pipelines, penstock, boilers, septic tanks, utility vaults, tank cars and other mobile containers.

Why Are Confined Spaces Dangerous?

Common hazards present in confined spaces include atmospheric conditions (oxygen deficiency, hydrogen sulfide, methane, and inert gases), engulfment, mechanical asphyxiation (from loose materials like grain, agricultural products, sand, cement, and gravel), and falls.

Among these, the leading cause of incidents and fatalities is atmospheric conditions, as reflected in OSHA’s 2019 fatality database, which the Z117 committee reviewed for the development of ANSI/ASSP Z117.1-2022.

This data revealed 34 cases of possible confined space fatalities: 18 involved asphyxiants and toxic exposures, 12 involved engulfment by grain or water, 3 involved falls, and 1 involved a mechanical auger.

What is ANSI/ASSP Z117.1-2022?

ANSI/ASSP Z117.1-2022 provides minimum safety requirements while entering, exiting, and working in confined spaces at ambient atmospheric pressure.

This standard keeps workers safe from confined spaces by addressing the identification and evaluation of confined spaces, non-permit confined spaces (NPCS), permit required confined spaces (PRCS) permit system, atmospheric testing, entry team responsibilities, hazardous energy isolation and lockout/tagout, ventilation, cleaning and decontamination, personal protective equipment (PPE), training, and other relevant concerns.

ANSI/ASSP Z117.1-2022 revises ANSI/ASSE Z117.1-2016; the change in the title is the result of the American Society of Safety Engineers (ASSE) changing its name to the American Society of Safety Professionals (ASSP) in 2018.

What Does ANSI/ASSP Z117.1-2022 Not Cover?

Since ANSI/ASSP Z117.1-2022 is a performance standard, it does not deal with confined space design. When considering design modifications, another American National Standard, ANSI/ASSP Z590.3-2021: Prevention Through Design Guidelines For Addressing Occupational Hazards And Risks In Design And Redesign Processes, should be consulted. It is also noted in the Foreword of ANSI/ASSP Z117.1-2022 that the design process is best handled by the purchaser, employer, or owner during a project’s design, acquisition, or construction.

This standard does not apply to industries that have their own specific national consensus standards for confined spaces. This includes the maritime, agriculture, and construction industries, among others. Some of these are addressed by OSHA confined spaces standards.

ANSI/ASSP Z117.1-2022 also specifically excludes the following activities: underground mining, tunneling, caisson work, excavations, and intentionally inert confined spaces or other similar tasks.

ANSI/ASSP Z117.1-2022: Safety Requirements For Entering Confined Spaces is available on the ANSI Webstore. Those in need of it and related American National Standards can get it as part of the ANSI/ASSE Z244.1 / ANSI/ASSE Z117.1 – Hazardous Energy Safety Package or the ANSI/ASSE Z490.1 / ANSI/ASSE Z117.1 – Confined Spaces Safety Training Set.

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