Understanding OSHA's Confined Space Requirements
Confined space entry is one of the most hazardous activities in any workplace. OSHA's Permit-Required Confined Space standard (29 CFR 1910.146) requires comprehensive programs to protect workers from serious hazards.
What Qualifies as a Confined Space?
A confined space has three characteristics:
**Large enough** for an employee to enter and perform work**Limited means of entry or exit** (not designed for continuous occupancy)**Not designed for continuous human occupancy**Examples: tanks, vessels, silos, storage bins, vaults, pits, manholes, tunnels, pipelines
Permit-Required vs. Non-Permit Spaces
A permit-required confined space has one or more of these hazards:
Hazardous atmosphere: - oxygen deficiency/enrichment, flammable gases, toxic substancesEngulfment hazard: - risk of being buried by materialConfiguration hazard: - inwardly converging walls, sloping floorsOther serious hazards: - energy sources, moving partsKey Program Elements
1. Written Program
Your program must include:
Methods for identifying confined spacesProcedures for atmospheric testingPermit system requirementsEntry proceduresRescue and emergency servicesTraining requirements2. Atmospheric Testing
Test before entry and continuously during work:
Oxygen: 19.5% to 23.5% required
Below 19.5%: oxygen deficient (asphyxiation risk)Above 23.5%: oxygen enriched (fire/explosion risk)Flammable gases: Below 10% of LEL (Lower Explosive Limit)
Toxic substances: Below OSHA PEL (Permissible Exposure Limit)
Testing order matters: Test for oxygen first, then flammables, then toxics.
Stratification: Test at multiple levels (top, middle, bottom) as gases stratify by density.
3. Ventilation
Before entry:
Ventilate space to remove hazardous atmospheresContinue ventilation during entry when possiblePosition air supply to sweep entire spaceMonitor effectiveness with continuous testing4. Permit System
Entry permits must include:
Space identification and purposeDate and authorized durationNames of entrants and attendantsName of entry supervisorHazards of the spaceIsolation methodsAtmospheric test resultsRescue proceduresCommunication methodsEquipment required5. Rescue Planning
You must have rescue capability before entry:
Non-entry rescue (preferred):
Retrieval lines attached to entrantsMechanical retrieval device at entry pointAllows rescue without entering the spaceEntry rescue:
Trained rescue team (internal or external)Appropriate equipment immediately availablePractice rescues from representative spacesThird-party rescue services:
Verify capability and availabilityProvide information about your spacesConduct joint training/drillsRoles and Responsibilities
Entry Supervisor
Issues permitsVerifies safety measuresTerminates entry when conditions changeCancels permits when entry is completeAttendant
Maintains communication with entrantsMonitors for hazardsControls access to the spaceSummons rescue if neededNever enters the space for rescueEntrant
Follows proceduresMaintains communicationAlerts attendant to hazardsExits when ordered or conditions changeCommon Violations and Mistakes
Frequently cited issues:
No atmospheric testing before entryInadequate rescue planningUntrained personnelNo attendant stationed at entryFailure to isolate energy sourcesPermits not properly completedUsing non-explosion-proof equipment in flammable atmospheresTraining Requirements
Initial training must ensure:
Understanding of space hazardsProper use of equipmentKnowledge of signs and symptoms of exposureCommunication proceduresRole-specific dutiesRefresher training when:
Duties changeHazards changeInadequate knowledge observedAnnual review recommendedRecent Developments and Best Practices
Enhanced monitoring technology:
Wireless gas detection with real-time data transmissionVideo monitoring of entrantsPersonal locator devicesImproved rescue equipment:
Self-contained breathing apparatus specifically designed for confined space rescueAdvanced communication systemsLighter, more portable retrieval systemsProgram improvements:
Pre-entry briefings for all entriesPost-entry debriefs to capture lessons learnedRegular rescue drills (not just annual)Integration with contractor safety programsCritical Dynamics provides comprehensive confined space program development, training, and rescue planning services. Contact us to evaluate your program against current best practices.