Confined Space Entry Activity Hazard Analysis
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Confined space entry remains one of the deadliest activities in construction. OSHA data consistently shows that 60% of confined space fatalities involve would-be rescuers who enter without proper equipment or training. On USACE and DoD construction projects, EM 385-1-1 Section 06.G imposes requirements that exceed OSHA general industry standards, recognizing that construction confined spaces present unique challenges: changing atmospheric conditions, multiple trades working sequentially, and spaces not originally designed for human entry.
This Activity Hazard Analysis covers permit-required confined space entry as a Definable Feature of Work under USACE contract requirements. The initial Risk Assessment Code of High (2) reflects the catastrophic severity potential, since atmospheric hazards and engulfment can cause death within minutes, combined with the occasional probability of encountering these conditions on an active construction site. With full implementation of atmospheric monitoring, ventilation, rescue planning, and trained entry teams, the residual RAC reduces to Low (5).
Every confined space entry on a USACE project requires a site-specific permit signed by the Entry Supervisor before any person breaks the plane of the opening. This AHA must be reviewed with the entire entry team, including the entrant, attendant, and entry supervisor, before each entry. It must be updated when space conditions change, when new hazards are identified, or after any emergency or rescue event.
Disclaimer
This content is provided for general informational and educational purposes only. It is not a substitute for a site-specific Job Safety Analysis conducted by a qualified safety professional familiar with your workplace conditions, equipment, and personnel. OSHA citations, BLS statistics, and hazard controls referenced here may not reflect the most current standards or apply to your specific situation. Always consult current OSHA regulations, manufacturer guidelines, and a competent person before beginning work. Health & Safety Systems LLC assumes no liability for actions taken based on this content.
Definable Feature of Work (DFOW)
Confined Space Entry & Work
Entry into and work within permit-required confined spaces including manholes, vaults, tanks, vessels, pits, tunnels, pipelines, and other spaces that meet the OSHA definition under 29 CFR 1926.1202. Includes pre-entry preparation, atmospheric monitoring, entry operations, and rescue standby.
Typical Duration: Individual entries typically 1-4 hours; DFOW may span days to weeks depending on scope of interior work
EM 385-1-1 References
Section 06.G: Confined Spaces
Primary section governing all confined space operations on USACE projects. Requires written confined space program, permit system, atmospheric monitoring, ventilation, rescue capability, and competent person oversight. More stringent than OSHA 1926 Subpart AA in several areas.
Section 06.G.01: Confined Space Program
Contractor must establish a written confined space program that identifies all permit-required confined spaces on the project, classifies hazards, and establishes entry procedures. Program must be included in the Accident Prevention Plan (APP).
Section 06.G.02: Entry Permits
Permits must be completed and signed by the Entry Supervisor before entry. Permits document atmospheric test results, ventilation status, communication methods, rescue provisions, and authorized entrants. Permits are valid for one shift maximum.
Section 06.G.03: Atmospheric Testing and Monitoring
Requires pre-entry testing and continuous monitoring during entry for oxygen, flammable gases, and toxic substances. Testing must be performed by a competent person using calibrated, direct-reading instruments.
Section 06.A: Personal Protective Equipment
PPE selection based on hazard assessment specific to the confined space. May include supplied-air respirators, chemical-resistant clothing, and retrieval harnesses.
Section 06.G.05: Rescue and Emergency Services
Non-entry rescue is the preferred method. If entry rescue is necessary, rescue team must be trained, equipped, and capable of responding within a timeframe appropriate to the identified hazards. Rescue drills required.
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Start Free TrialRisk Assessment Code (RAC)
The RAC matrix combines hazard severity and probability to assign a risk level before and after controls are applied. This AHA demonstrates risk reduction from initial to residual conditions.
Initial Risk (Before Controls)
High (2)
Severity: Catastrophic | Probability: Occasional
Residual Risk (After Controls)
Low (5)
Severity: Marginal | Probability: Unlikely
Step-by-Step AHA Breakdown
Step 1: Identify and classify the confined space
Hazards
- Misclassification of a permit-required space as non-permit, leading to entry without proper controls
- Unknown atmospheric hazards from previous contents, biological decomposition, or adjacent processes
- Unidentified engulfment or entrapment hazards
Controls
- Evaluate the space against OSHA 1926.1202 criteria: limited openings, not designed for continuous occupancy, large enough to enter and perform work
- Research space history including previous contents, connected systems, and adjacent processes
- Classify as permit-required if any atmospheric, engulfment, entrapment, or other serious hazard exists or could exist
- Document classification on the confined space inventory and in the project APP
Step 2: Prepare confined space entry permit
Hazards
- Incomplete hazard identification leading to inadequate controls
- Failure to isolate energy sources connected to the space
- Entry without authorization or proper documentation
Controls
- Entry Supervisor completes all sections of the confined space entry permit
- Identify all energy sources (mechanical, electrical, hydraulic, pneumatic, chemical, thermal) and document isolation method for each
- Verify lockout/tagout of all energy sources; blank or disconnect all lines that could introduce hazardous materials
- Establish communication methods between entrant and attendant
- Document rescue provisions and verify rescue team availability
- Post completed permit at the entry point
Step 3: Isolate the space and establish ventilation
Hazards
- Unexpected energy release from improperly isolated systems
- Introduction of hazardous atmosphere from connected piping or adjacent spaces
- Oxygen-deficient or oxygen-enriched atmosphere
Controls
- Lock out and tag out all energy sources per EM 385-1-1 Section 12.D
- Blank or disconnect all lines that could introduce hazardous substances; do not rely on valves alone
- Install continuous forced-air mechanical ventilation before entry and maintain throughout
- Position ventilation to supply fresh air to the work area and exhaust contaminated air away from the entry point
- Do not use pure oxygen for ventilation
Step 4: Perform atmospheric testing
Hazards
- Oxygen deficiency (below 19.5%) causing unconsciousness and death
- Oxygen enrichment (above 23.5%) creating fire and explosion risk
- Flammable gas or vapor accumulation above 10% LEL
- Toxic gas exposure (H2S, CO, and other space-specific contaminants)
Controls
- Test atmosphere with calibrated direct-reading instrument before any person enters the space
- Test at multiple levels (top, middle, bottom) to account for gas stratification
- Test in the following order: oxygen, flammable gases, toxic gases
- Entry criteria: O2 19.5-23.5%, LEL below 10%, toxic gases below applicable PEL/TLV
- Record all test results on the entry permit with time, location, and reading
- Do not enter if any reading exceeds acceptable limits until conditions are corrected and re-tested
Step 5: Brief entry team and don PPE
Hazards
- Workers unaware of space-specific hazards or emergency procedures
- Inadequate PPE selection for the hazards present
- Retrieval system not properly fitted or connected
Controls
- Entry Supervisor briefs all team members on space hazards, entry permit conditions, communication signals, and emergency procedures
- Each entrant dons PPE based on hazard assessment: retrieval harness with D-ring, hard hat, gloves, and additional protection as conditions require
- Connect retrieval line to harness D-ring and mechanical retrieval device (tripod/davit) unless retrieval line creates a greater hazard
- Attendant verifies communication equipment is functional
- All team members sign the entry permit
Step 6: Enter and perform work in the confined space
Hazards
- Atmospheric changes during work from welding, painting, grinding, or chemical use
- Heat stress from limited air circulation and physical exertion
- Slips and falls on wet, uneven, or sloped interior surfaces
- Entrapment from converging walls, sloped floors, or stored materials
Controls
- Continuous atmospheric monitoring by entrant wearing a personal 4-gas monitor
- Attendant monitors entrant condition and maintains continuous communication
- Attendant maintains accurate count of all persons in the space at all times
- Immediate evacuation if any atmospheric alarm triggers, if the entrant shows signs of distress, or if conditions change
- Maintain forced-air ventilation continuously; increase ventilation if contaminant-generating work is performed inside
- Schedule work/rest cycles for heat stress management in poorly ventilated spaces
Step 7: Maintain rescue standby
Hazards
- Delayed rescue response resulting in entrant death or permanent injury
- Untrained rescuers becoming additional victims
- Rescue equipment failure or unavailability
Controls
- Non-entry retrieval system (tripod/davit with mechanical winch) set up and ready at the entry point
- Trained rescue team on site or within documented response time appropriate to the hazards
- Rescue team has practiced retrieval from a comparable space within the past 12 months
- SCBA or SAR available for rescue team use
- Emergency services notified of confined space work location and access routes
- Under no circumstances shall an untrained person attempt entry rescue
Step 8: Exit the space and close out the permit
Hazards
- Entrant collapse during egress from accumulated exposure or exertion
- Space left unsecured after entry, allowing unauthorized re-entry
- Failure to document conditions for subsequent entries
Controls
- Attendant verifies all entrants have exited and accounts for all personnel
- Remove all tools, equipment, and materials from the space
- Secure the entry opening to prevent unauthorized entry (cover, barricade, or lock)
- Entry Supervisor cancels the entry permit and documents final atmospheric readings
- Retain completed permits for the duration of the project
- Debrief the entry team; document any observations for future entries
Competent & Qualified Persons
EM 385-1-1 requires designated competent and qualified persons for specific activities. These individuals must have the training, experience, and authority to identify hazards and take corrective action.
Entry Supervisor
Must be designated in writing. Responsible for authorizing entry, verifying that all permit conditions are met, terminating entry when conditions change, and ensuring rescue services are available. Must have training in atmospheric monitoring, hazard recognition, and confined space entry procedures per EM 385-1-1.
EM 385-1-1 Reference: Section EM 385-1-1 Section 06.G.01
Attendant
Trained in attendant duties including continuous monitoring of entrants, maintaining communication, keeping an accurate headcount, recognizing signs of exposure, and initiating non-entry rescue. Must not enter the space for any reason. Must not perform duties that interfere with monitoring.
EM 385-1-1 Reference: Section EM 385-1-1 Section 06.G.01
Confined Space Rescue Team Member
Must be trained and certified in confined space rescue techniques, SCBA/SAR use, first aid and CPR. Must have practiced making rescues from confined spaces within the past 12 months. If using third-party rescue services, contractor must verify capability and response time.
EM 385-1-1 Reference: Section EM 385-1-1 Section 06.G.05
Atmospheric Monitoring Competent Person
Trained in the use, calibration, and limitations of direct-reading atmospheric monitoring instruments. Must understand gas properties (specific gravity, LEL/UEL, PELs/TLVs) and be able to interpret readings in context of the space configuration.
EM 385-1-1 Reference: Section EM 385-1-1 Section 06.G.03
Equipment, Training & Inspection Requirements
Required Equipment
Training Requirements
- OSHA 30-Hour Construction Safety (required for supervisors on USACE projects)
- Site-specific safety orientation per EM 385-1-1 Section 01.A.13
- Confined space entry training per 29 CFR 1926.1207 (authorized entrants)
- Confined space attendant training per 29 CFR 1926.1209
- Entry Supervisor training per 29 CFR 1926.1210
- Atmospheric monitoring equipment operation and calibration
- Confined space rescue training with hands-on practice (rescue team members)
- CPR and first aid certification (rescue team members)
- SCBA/SAR donning, use, and emergency procedures (rescue team members)
- Lockout/tagout training per EM 385-1-1 Section 12.D
- Hazard Communication training for substances that may be present in or introduced to the space
Inspection Requirements
- Daily calibration bump test of all atmospheric monitoring instruments before use
- Full calibration of atmospheric monitors per manufacturer schedule (typically every 30 days)
- Pre-entry atmospheric testing at multiple levels in the space
- Continuous atmospheric monitoring during all entry operations
- Pre-use inspection of retrieval system (tripod/davit, winch, retrieval line, harness)
- Annual load testing of mechanical retrieval equipment
- Monthly inspection of SCBA/SAR equipment and air supply
- Pre-entry verification of all energy isolation points (lockout/tagout)
- Post-entry inspection of the space opening to verify it is secured against unauthorized entry
- Weekly documented safety inspection of confined space operations by site safety representative
Applicable OSHA Standards
29 CFR 1926.1203
General Requirements (Confined Spaces in Construction)
Requires employers to identify confined spaces and permit-required confined spaces, inform exposed employees, and prevent unauthorized entry. Establishes the framework for the construction confined space program.
29 CFR 1926.1204
Permit-Required Confined Space Program
Requires a written program for permit space entry including hazard evaluation, entry procedures, atmospheric monitoring, ventilation, communication, rescue, and permit documentation.
29 CFR 1926.1211
Rescue and Emergency Services
Requires evaluation of rescue service capability and response time. On-site rescue teams must practice retrieval from representative spaces annually. Non-entry rescue is preferred when feasible.
29 CFR 1926.1204(e)
Atmospheric Testing Requirements
Specifies testing sequence (oxygen, flammables, toxics), acceptable entry conditions, and continuous monitoring requirements during entry operations.
29 CFR 1926.1206
Entry Permit
Defines required content of confined space entry permits including space identification, purpose of entry, date/duration, authorized entrants, hazards, controls, atmospheric test results, rescue provisions, and communication procedures.
Required Personal Protective Equipment
Frequently Asked Questions
When does a confined space require a permit under EM 385-1-1?
A confined space requires a permit when it contains or has the potential to contain a hazardous atmosphere, contains material with engulfment potential, has an internal configuration that could trap or asphyxiate an entrant, or contains any other recognized serious safety or health hazard. On USACE projects, EM 385-1-1 Section 06.G generally requires permit-based entry for all confined spaces unless the space has been formally reclassified through documented testing and hazard elimination.
Can a permit-required confined space be reclassified as non-permit?
Yes, under 29 CFR 1926.1203(g), a permit space may be reclassified as a non-permit space if all hazards can be permanently eliminated without entry (or through entry under the permit program). Atmospheric hazards must be eliminated through continuous forced-air ventilation, and the space must be documented and re-evaluated if conditions change. Reclassification must be documented and available for review by the COR.
What is the required rescue response time on USACE projects?
EM 385-1-1 does not specify an exact response time in minutes, but requires that rescue capability be appropriate to the hazards present. For spaces with IDLH atmospheres, rescue must be immediately available (on-site rescue team with equipment ready). For non-IDLH spaces, the contractor must document that the rescue service can respond within a timeframe that prevents serious injury. Many USACE safety offices require on-site rescue capability for all permit-required entries.
How often must atmospheric monitoring instruments be calibrated?
A bump test (functional check with known concentration of calibration gas) is required before each use, typically at the start of each shift. Full span calibration must be performed per manufacturer recommendations, which is typically every 30 days or after any failed bump test. Calibration records must be maintained and available for review. Instruments that fail bump testing must be removed from service until full calibration is completed.
What is the difference between a confined space AHA and a confined space entry permit?
The AHA is a pre-task planning document that identifies all hazards associated with confined space entry as a DFOW, establishes controls, and documents training and equipment requirements. It is submitted once and covers the general activity. The entry permit is a shift-specific authorization document completed before each individual entry that documents actual atmospheric readings, specific isolation points, named entrants and attendants, and rescue provisions for that entry. Both are required on USACE projects; they serve complementary but distinct purposes.