🔒 Confined Space Entry Playbook
Manage confined space entry safely on commercial construction projects. Proper permit procedures, atmosphere testing, and rescue planning protect workers from engulfment, atmospheric hazards, and entrapment.
Why This Matters
| Without Proper Confined Space Procedures | With Proper Procedures |
|---|---|
| Multiple fatalities from atmospheric hazards | Atmosphere tested before and during entry |
| Entrapment with no rescue plan | Rescue plan established before entry |
| Workers enter unaware of hazards | Permit documents hazards and controls |
| Unauthorized entries without oversight | Entry supervisor, attendant, and entrant roles defined |
| No documentation for OSHA or legal defense | Full permit trail and atmospheric readings logged |
Plan Before Entry
Confined space rescues are complex. The moment someone is unconscious in a manhole, it's too late to figure out who has rescue training. Establish the rescue plan before anyone enters.
Confined Space vs. Permit-Required Confined Space
| Type | Definition | Examples |
|---|---|---|
| Confined Space | Space large enough to enter, limited entry/egress, not designed for occupancy | Crawl space, duct, pipe run |
| Permit-Required (PRCS) | Confined space PLUS one or more: hazardous atmosphere, engulfment hazard, configuration that traps, or other serious hazard | Manhole, vault, tank, elevator pit with mechanical hazards |
If it's a PRCS, you need a permit and the full workflow below.
Identifying Confined Spaces on Commercial Projects
| Location | Common Confined Spaces |
|---|---|
| Site/Utility | Manholes, vaults, drainage structures, storm sewers |
| Building | Elevator pits, crawl spaces, mechanical rooms with tanks |
| Process | Tanks, silos, vessels, boilers |
| Distribution | Pipe runs, ductwork, tunnels |
| Underground | Trenches over 4 feet with limited egress |
Roles and Responsibilities
| Role | Responsibilities |
|---|---|
| Entry Supervisor | Authorize entry, verify permit conditions met, terminate entry if conditions change, sign and close permit |
| Entrant | Enter space, understand hazards, wear PPE, communicate with attendant, evacuate on signal |
| Attendant | Monitor entrants from outside, maintain communication, summon rescue, never enter to rescue |
| Rescue Team | Standby or on-call per plan; must be trained and equipped for the specific space |
Step-by-Step Entry Permit Workflow
Phase 1: Identify → Evaluate → Classify
- Identify — Survey the site for confined spaces before work begins
- Evaluate — Determine if each space is confined and if it meets PRCS criteria
- Classify — Document as non-permit confined space or PRCS; label PRCS spaces
Phase 2: Permit → Pre-Entry
-
Permit — Complete the confined space entry permit with:
- Space identification and location
- Hazards (atmospheric, engulfment, configuration)
- Required controls and PPE
- Acceptable atmospheric limits
- Rescue plan (on-site team or 911)
- Entry supervisor and permit expiration
-
Pre-Entry — Before anyone enters:
- Conduct atmosphere testing (see below)
- Verify ventilation if required
- Confirm rescue team is ready
- Brief all entrants and attendant
Phase 3: Entry → Monitoring → Exit → Close
- Entry — Entrants enter only after permit conditions are met
- Monitoring — Attendant monitors continuously; re-test atmosphere as required (typically every 15–30 minutes or per procedure)
- Exit — All entrants exit; permit expires when work is complete or conditions change
- Close — Entry supervisor signs off; file permit for record retention
Atmosphere Testing Requirements
Test in this order: O₂ → LEL (combustible gas) → H₂S → CO
| Gas | Acceptable Limit | Action if Exceeded |
|---|---|---|
| Oxygen (O₂) | 19.5% – 23.5% | Below 19.5%: hypoxia risk. Above 23.5%: fire/explosion risk. Do not enter. |
| LEL (Lower Explosive Limit) | < 10% | Evacuate immediately above 10%; ventilate and re-test before re-entry |
| Hydrogen Sulfide (H₂S) | < 10 ppm | IDLH at 100 ppm; evacuate per SDS and procedure |
| Carbon Monoxide (CO) | < 25 ppm (8-hr TWA) | Evacuate at 35 ppm; IDLH at 1,200 ppm |
Calibrate and Document
Calibrate gas monitors before each use (bump test). Log all atmospheric readings on the permit.
BLDR Pro for Permit Documentation
Use BLDR Pro to store confined space permits, atmosphere reading logs, and photos of gas monitor displays. Attach documentation to daily reports and project files. When OSHA or an incident investigation asks "was the atmosphere tested?" — you'll have timestamped proof.
Rescue Plan
Decide before entry — not during an emergency.
| Option | When to Use | Requirements |
|---|---|---|
| On-Site Rescue Team | Complex spaces, high entry frequency | Trained, equipped, practice drills; response time within 4 minutes |
| 911 / External Rescue | Lower risk, infrequent entry | Verify local rescue capability; provide space info to fire department |
Rescue plan must include: Who is called, contact numbers, space information, access/egress points, and that rescue personnel do not enter unless trained and equipped.
Pre-Entry Permit Checklist
Before signing the permit, the entry supervisor must verify:
- Atmosphere tested (O₂, LEL, H₂S, CO) — results within limits
- Rescue team or 911 plan confirmed and ready
- Ventilation in place if required
- PPE available and correct for hazards
- Entrant and attendant trained and briefed
- Communication method established
- Permit expiration time set
Communication and Monitoring
- Attendant stays outside — Never leaves post while entrants are inside
- Continuous communication — Visual, verbal, or mechanical (pull signal, radio)
- Re-test atmosphere — Per procedure (e.g., every 15–30 minutes or when conditions change)
- Evacuate signal — All entrants must recognize and respond immediately
Metrics to Track
| Metric | Target | Frequency |
|---|---|---|
| Permits issued per confined space entry | 100% | Per entry |
| Atmospheric readings logged | 100% | Per test |
| Rescue drills conducted | Per plan (e.g., annually) | Quarterly review |
| Unauthorized entries | 0 | Per incident |
| Attendant training completion | 100% | Annual |
Common Mistakes
| Mistake | Problem | Fix |
|---|---|---|
| Entering without a permit | Invisible hazards (low O₂, H₂S) kill quickly | Never enter PRCS without completed permit |
| Skipping atmosphere testing | "It's just a manhole" — fatal assumption | Test every time, in correct order |
| Attendant enters to rescue | Two victims instead of one | Attendant summons rescue; never enters |
| No rescue plan | Delayed response, fatalities | Establish plan before first entry |
| Outdated permit | Conditions change (rain, adjacent work) | Re-evaluate and re-issue permit when conditions change |
Troubleshooting
"We're not sure if it's a confined space"
- If it has limited entry/egress and wasn't designed for occupancy, treat it as confined. Evaluate for PRCS criteria. When in doubt, treat as PRCS.
"Atmosphere readings are borderline"
- Do not enter. Ventilate, re-test, or reclassify. "Borderline" means unsafe.
"Our local fire department doesn't do confined space rescue"
- You must have an on-site rescue team or contract with a rescue service. 911 is not a plan if they're not equipped for confined space.
"Subcontractor is entering a confined space we didn't know about"
- GC must identify all confined spaces in the pre-construction phase and communicate to all subs. Audit sub work plans; require sub permits for any PRCS entry.
"Permit expired but work isn't finished"
- Do not continue. Conditions may have changed. Re-evaluate the space, re-test atmosphere, and issue a new permit before re-entry. Permits typically expire at end of shift or when conditions change.
Related Resources
| Resource | Link |
|---|---|
| Confined Space Guide | Confined Space Guide |
| JSA/JHA Playbook | JSA/JHA Process |
| Incident Reporting Playbook | Incident Reporting |
| Trenching Toolbox Talk | Trenching Safety |