OSHA’s General Industry Regulation: 29 CFR 1910.146, Permit-Required Confined Spaces

“You can’t overstate the impact the confined space legislation has had on the safety of workers. Before the standard was implemented, there was no guidance on gas detection. Few workers carried gas monitors, and there was little concern over entering a confined space. Today, everything is different. This standard gives greater visibility into gas hazards and has initiated a focus on safety that has paved the way for similar legislation around the world.” –Dave Wagner, Director of Applications Engineering and Product Knowledge, Industrial Scientific, www.indsci.com


OSHA issued a general industry standard (29 CFR 1910.146) on January 14, 1993, to require protection for employees who enter permit-required confined spaces. The permit space standard, which provides a comprehensive regulatory framework for the safe performance of entry operations in general industry workplaces, became effective April 15, 1993.

Why Standard is Important

OSHA’s Permit-Required Confined Spaces manual overviews this standard, stating: “Many workplaces contain spaces that are considered to be ‘confined,’ because their configurations hinder the activities of employees who must enter into, work in or exit from them. Due to the work environment, employees who perform tasks in confined spaces also face increased risk of exposure to serious physical injury from hazards, such as entrapment, engulfment and hazardous atmospheric conditions.”

Confinement itself may pose entrapment hazards, and work in confined spaces may keep employees closer to hazards, such as machinery components, than they would be otherwise. The terms “permit-required confined space” and “permit space” refer to spaces that meet OSHA’s definition of a “confined space” and contain health or safety hazards. For this reason, OSHA requires workers to have a permit to enter these spaces.

Key Compliance Requirements

According to osha.gov, OSHA’s standard for confined spaces (29 CFR 1910.146) contains the requirements for practices and procedures to protect employees in general industry from the hazards of entering permit spaces. Employers in general industry must evaluate their workplaces to determine if spaces are permit spaces. If a workplace contains permit spaces, the employer must inform exposed employees of their existence, location and the hazards they pose. This can be done by posting danger signs, such as “DANGER—PERMIT-REQUIRED CONFINED SPACE—AUTHORIZED ENTRANTS ONLY” or using an equally effective means.

If employees are not to enter and work in permit spaces, employers must take effective measures to prevent them from entering these spaces. If employees are expected to enter permit spaces, the employer must develop a written permit space program and make it available to employees or their representatives.

Alternative to a full permit entry under certain conditions described in the standard, the employer may use alternate procedures for worker entry into a permit space. For example, if an employer can demonstrate with monitoring and inspection data that the only hazard is an actual or potential hazardous atmosphere that can be made safe for entry using continuous forced-air ventilation, the employer may be exempted from some requirements, such as permits and attendants. However, even in these circumstances, the employer must test the internal atmosphere of the space for oxygen content; flammable gases and vapors; and the potential for toxic air contaminants—before any employee enters it. The employer must also provide continuous ventilation and verify that the required measurements are performed before entry.


OSHA offers help and training through several programs, including technical assistance about effective safety and health programs, state plans, workplace consultations, voluntary protection programs, strategic partnerships, training and education.

For a complete detailed on this standard, go to https://bit.ly/2re6oei.

For an article on gas detection in confined spaces, see “Gas Detection and Monitoring in Confined Spaces,” Workplace Material Handling & Safety, March 2018. Go to workplacepub.com for more on this and many other safety topics.

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