Confined Space Safety
This document will outline the basics of confined space safety, including the differences and requirements for non-permit and permit required spaces.
1. Confined Space Definition & Criteria
What defines a Confined Space?
A space is considered a confined space if it meets ALL three of the following conditions:
- Sized for Entry: It is large enough for an employee to bodily enter and perform work, AND
- Restricted Access: It has limited or restricted means of entry or exit, AND
- Not Designed for Continuous Occupancy: It is not designed for continuous employee occupancy.
Working Rule of Thumb: If you must use your hands to enter or exit, or if working in the space during normal operation poses inherent hazards to your well-being, treat it as a confined space.
Common Examples
Typical confined spaces across campus include:
- Tanks and storage vessels
- Boilers
- Manholes, utility vaults, and tunnels
- Grain storage bins and silos
2. Confined Space Classifications
Types of Confined Spaces
Non-Permit Required Confined Space
A space that meets the three basic criteria but does not contain (or have the potential to contain) any atmospheric or physical hazard capable of causing death or serious physical harm.
- Examples: Fresh air ducts, drop ceiling spaces.
Permit-Required Confined Space
A space that contains or has the potential to contain one or more of the following safety hazards:
- Hazardous atmosphere (oxygen deficiency/enrichment, toxic or flammable gases)
- Engulfment hazard (liquid or flowable solids)
- Internal configuration causing entrapment (converging walls, sloping floors)
- Any other recognized serious safety or health hazard
Who is authorized to enter?
Authorized Personnel Only: Only employees who have completed the official Workplace Safety Confined Space Authorized Employee Training are permitted to enter designated confined spaces.
3. Hazards & Safety Controls
Hazardous Atmospheres
- Oxygen Deficiency (< 19.5% O₂): NOT SAFE. Causes include leaking natural gas lines, rusting metal, drying paint, fuel combustion, bacterial activity, welding/cutting activities, dilution by inert gases (e.g., Nitrogen, Carbon Dioxide), or chemical oxygen consumption.
- Oxygen Enrichment (> 23.5% O₂): FIRE & EXPLOSION HAZARD. Typically caused by leaking oxygen hoses, cylinders, or torches.
General Physical Hazards
- Engulfment: Entrapment by liquid or flowable solid contents (e.g., water, oil, grain, sand).
- Entrapment: Being trapped or asphyxiated due to inwardly converging walls or floor structures sloping downward to a narrow cross-section.
- Asphyxiation: Suffocation or loss of consciousness due to lack of oxygen or dangerous atmospheric conditions.
Required Control Measures
Prior to and during entry, the following controls must be applied:
- Air Monitoring: Test atmospheric conditions prior to entry and continuously as required.
- Ventilation: Use mechanical forced-air ventilation to maintain safe atmospheric conditions.
- Buddy System: Maintain a designated attendant outside the space at all times during entry.
- Entry Permit: Complete and post a fully authorized CS Entry Permit for all permit-required entries.
4. Required Forms & Training Resources
Assessment & Permit Forms