A new manhole can still contain hazardous air or receive water, gas or engine exhaust. Sampling at the opening does not establish conditions at all work locations or later times; select the gases, instrument, locations and timing for the actual hazards.
This reference material was written and revised with AI. It has not been verified or approved by a professional. Review by a suitably qualified professional and required site approval are necessary before field use.
Stop before proceeding
Exit immediately for gas alarms, ventilation or communication loss, or changing inflow. Do not enter during block lowering or with unstable support or unverified rescue arrangements.
1. Legal and technical scope
Construction excavation is assessed under 1926.651/.652; evaluate the manhole interior separately under Subpart AA, including 1926.1203/.1204 and rescue under 1926.1211. The Subpart P excavation exclusion does not automatically exempt a constructed manhole interior. General-industry entries require the applicable 1910.146 program. This JSA is not an entry permit or a substitute for host, controlling and entry-employer coordination.
Confirm whether federal OSHA or an OSHA-approved State Plan covers this employer and worksite; state requirements and public-sector coverage can differ. Apply the task-specific provisions and limitations identified above.
| Basis | Application |
|---|---|
| OSHA 29 CFR 1926.651 | Excavation conditions, access, utilities and competent-person inspection. |
| OSHA 29 CFR 1926.652 | Excavation protective systems. |
| OSHA 29 CFR 1926.1203 | Construction space evaluation, entry controls and employer coordination. |
| OSHA 29 CFR 1926.1204 | Permit-space program, isolation, entry conditions and atmospheric monitoring requirements with specified exceptions. |
| OSHA 29 CFR 1926.1211 | Rescue capability evaluation, arrangements and retrieval requirements. |
| OSHA State Plans | Official overview of federal and State Plan jurisdiction and differing public-sector coverage, checked 2026-10-12. Individual state rules require a site-specific check. |
2. Scope and required inputs
Included scope
Prepare the foundation, lift and join precast manhole sections, evaluate and authorize any interior finishing, monitor entry, exit, close and hand over the installation.
Separate assessment
Live sewer changeovers, high-pressure cleaning, diving and emergency entry into an unsafe atmosphere require separate specialized procedures. Prefer non-entry assembly and inspection where feasible.
| Input | Evidence needed |
|---|---|
| Evaluate location | Connections and inflows; Work and space classification; Non-entry alternatives; Rescue capability. |
| Inspect blocks | Block ID and condition; Insert and rigging fit; Weight and crane plan; Level and bearing. |
| Authorize entry | Gas instrument and results; Permit and entry limits; Ventilation and isolation; Attendant contact and rescue. |
| Close and handoff | Exit and tool count; Cover and traffic state; Flow restoration sequence; Future entry restrictions. |
No site measurements, equipment manuals for the actual installation, inspection records or signed technical approvals were supplied. Confirm the applicable requirements and actual product instructions before use; record each criterion with its units, source and equipment or work-area ID.
3. Eight-stage JSA
| Job stage | Hazards and effects | Failure factors | Technical and procedural controls | Site verification | P | S | R | A |
|---|---|---|---|---|---|---|---|---|
| 1. Evaluate location | 1. Excavation collapse2. Engulfment3. Oxygen deficiency4. Toxic gas exposure | 1. Pipe links unknown2. Inflow overlooked3. New-space assumption4. Exhaust path missed | 1. Assess soil and utilities2. Map and control inflows3. Evaluate entry and alternatives4. Prepare entry and rescue plan | 1. Connections and inflows2. Work and space classification3. Non-entry alternatives4. Rescue capability | ||||
| 2. Protect excavation | 1. Sidewall collapse2. Opening fall3. Vehicle strike4. Unsafe access | 1. Support inadequate2. Guard removed3. Traffic not separated4. Ladder unsecured | 1. Verify protective system2. Guard openings3. Separate equipment and people4. Provide secure access | 1. Competent inspection2. Rain and groundwater3. Opening and traffic barrier4. Access arrangement | ||||
| 3. Inspect blocks | 1. Dropped section2. Stack overturn3. Insert failure4. Foundation settlement | 1. Cracked block2. Weak storage3. Wrong lifting insert4. Uneven base | 1. Match weight and rigging2. Inspect lifting points3. Stabilize storage4. Verify foundation | 1. Block ID and condition2. Insert and rigging fit3. Weight and crane plan4. Level and bearing | ||||
| 4. Lower and join | 1. Worker crushed2. Joint pinch3. Block movement4. Rigging release | 1. Person inside2. Hand alignment3. Support incomplete4. Tension released early | 1. Clear inside and below2. Use alignment tools3. Check full bearing and joint4. Release by planned sequence | 1. Personnel clear2. Joint and alignment3. Stable support4. Rigging release criteria | ||||
| 5. Authorize entry | 1. Hazardous air2. Rescue delay3. Unexpected inflow4. Entrant isolated | 1. Opening-only test2. Rescue unprepared3. Isolation incomplete4. No attendant | 1. Test actual work locations2. Verify ventilation and rescue3. Control incoming hazards4. Establish attendant and contact | 1. Gas instrument and results2. Permit and entry limits3. Ventilation and isolation4. Attendant contact and rescue | ||||
| 6. Finish and monitor | 1. Changing atmosphere2. Material exposure3. Exhaust ingress4. Lost communication | 1. Monitoring inadequate2. Wrong coating3. Engine moved4. Contact interrupted | 1. Maintain required monitoring2. Control finishing materials3. Keep intake air clean4. Exit on unsafe change | 1. Work-zone measurements2. Material and ventilation3. External inflow sources4. Attendant and communication | ||||
| 7. Evacuate and respond | 1. Rescuer overcome2. Retrieval injury3. Extra fall4. Delayed response | 1. Impulsive entry2. Unplanned retrieval3. Opening unguarded4. No capable service | 1. Exit and raise alarm2. Use prepared rescue system3. Keep unauthorized people out4. Activate designated responders | 1. Entrant accountability2. Retrieval limits3. Rescue access and equipment4. Response contact | ||||
| 8. Close and handoff | 1. Entrant trapped2. Cover displaced3. Tool falls4. Flow restored early | 1. People not counted2. Fixing unchecked3. Tools left4. Sequence confused | 1. Account for people and tools2. Secure cover and barriers3. Check interior status4. Authorize staged restoration | 1. Exit and tool count2. Cover and traffic state3. Flow restoration sequence4. Future entry restrictions |
P = likelihood; S = severity; R = risk under the site method; A = the site-defined acceptance/authorization decision. Complete only after actual assessment. Blank cells and checklist prompts are not completed inspections.
4. Fictional scenario and failure mechanisms
Retained AI-generated educational illustration from the source edition; not a real incident photograph, approved installation drawing or evidence of equipment suitability.
The scenario and record comparisons are fictional teaching examples, not records of real incidents, measurements, inspections, signatures or approvals.
| Item | Fictional scenario |
|---|---|
| Initial | Interior finishing is planned in a newly assembled manhole. |
| Change | Only the opening was sampled; then the duct moves and a nearby engine directs exhaust toward it. |
| Failure | The crew relies on the old opening result and the fact that the structure is new. |
| Outcome | Workers can be exposed to hazardous air and an impulsive rescuer can become another casualty. |
| Barrier | Hold or evacuate entry, control incoming hazards and verify current work-zone air, ventilation, communication and rescue readiness. |
Why the controls matter
A new manhole can still contain hazardous air or receive water, gas or engine exhaust. Sampling at the opening does not establish conditions at all work locations or later times; select the gases, instrument, locations and timing for the actual hazards.
A running blower is not proof of clean air at the worker. Verify intake quality, duct position and delivery with the required testing/monitoring. For construction permit entry, use continuous atmospheric monitoring unless a documented regulatory exception applies; do not quietly substitute occasional checks.
A supported and joined block is not permission for entry. Treat load-support release and entry authorization as separate decisions. Prepare rescue before entry, including service capability, access and any non-entry retrieval limitations; simply writing 911 is not a complete rescue plan.
Decision sequence
| Step | Decision |
|---|---|
| Known | Only the opening was sampled; then the duct moves and a nearby engine directs exhaust toward it. |
| Unknown | Actual condition, extent of damage and suitability of gas instrument and results, permit and entry limits remain to be established. |
| Hold | The crew relies on the old opening result and the fact that the structure is new. |
| Evidence | Link gas instrument and results, permit and entry limits, ventilation and isolation, attendant contact and rescue, entrant accountability, retrieval limits to the affected equipment or work area. |
| Next | Hold or evacuate entry, control incoming hazards and verify current work-zone air, ventilation, communication and rescue readiness. |
5. Conditional decisions and common errors
| Condition | Action | Evidence | Proceed when |
|---|---|---|---|
| Only opening sampled | Hold entry | Work-zone gas assessment | Entry conditions verified |
| Ventilation or contact lost | Exit immediately | People accounted and re-evaluation | Re-entry authorized |
| Inflow changes | Exit and control source | Line, rainfall and exhaust review | Inflow controlled |
| Entrant collapses | Activate prepared rescue | Rescue team and equipment | No improvised entry |
Similar appearance, different evidence
The scenario and record comparisons are fictional teaching examples, not records of real incidents, measurements, inspections, signatures or approvals.
| Comparison | Supported decision | Insufficient basis |
|---|---|---|
| Condition | Work-zone gas assessment | Only opening sampled has not been resolved. |
| Evidence | Line, rainfall and exhaust review | A photograph or a completed-looking task without the relevant inspection record. |
| Release | No improvised entry | Completion of one step does not release the excluded tasks in section 2. |
6. Roles and responsibilities
| Role | Responsibility |
|---|---|
| Work supervisor | Assign the task boundary, stop authority, interfaces and emergency communication for precast manhole assembly and interior finishing. |
| Technical lead | Confirm Connections and inflows; Work and space classification; Non-entry alternatives; Rescue capability. Resolve design and manufacturer limits before work. |
| Authorized crew | Apply Block ID and condition; Insert and rigging fit; Weight and crane plan; Level and bearing. Stop when the working arrangement changes. |
| Inspector / receiving lead | Review Gas instrument and results; Permit and entry limits; Ventilation and isolation; Attendant contact and rescue. Transfer Exit and tool count; Cover and traffic state; Flow restoration sequence; Future entry restrictions. |
Role labels allocate responsibilities; they do not confer a legal qualification. Verify the competence, training and authority required for the actual task.
Record and handoff perspective
| Stage | Record controls | Verification |
|---|---|---|
| Evaluate location | 1. Record connections and inflows2. Record work and space classification3. Record non-entry alternatives | 1. Work and space classification2. Non-entry alternatives3. Rescue capability |
| Inspect blocks | 1. Record block id and condition2. Record insert and rigging fit3. Record weight and crane plan | 1. Insert and rigging fit2. Weight and crane plan3. Level and bearing |
| Lower and join | 1. Record personnel clear2. Record joint and alignment3. Record stable support | 1. Joint and alignment2. Stable support3. Rigging release criteria |
| Authorize entry | 1. Record gas instrument and results2. Record permit and entry limits3. Record ventilation and isolation | 1. Permit and entry limits2. Ventilation and isolation3. Attendant contact and rescue |
| Evacuate and respond | 1. Record entrant accountability2. Record retrieval limits3. Record rescue access and equipment | 1. Retrieval limits2. Rescue access and equipment3. Response contact |
| Close and handoff | 1. Record exit and tool count2. Record cover and traffic state3. Record flow restoration sequence | 1. Cover and traffic state2. Flow restoration sequence3. Future entry restrictions |
7. Hold points and record comparison
| Hold point | Evidence before release | Actual record |
|---|---|---|
| HP-0 Start | Prepare the foundation, lift and join precast manhole sections, evaluate and authorize any interior finishing, monitor entry, exit, close and hand over the installation. | |
| HP-1 Lower and join | Personnel clear; Joint and alignment; Stable support; Rigging release criteria | |
| HP-2 Authorize entry | Gas instrument and results; Permit and entry limits; Ventilation and isolation; Attendant contact and rescue | |
| HP-3 Finish and monitor | Work-zone measurements; Material and ventilation; External inflow sources; Attendant and communication | |
| HP-4 Close and handoff | Exit and tool count; Cover and traffic state; Flow restoration sequence; Future entry restrictions |
These are internal hold points, not issued permits. Recheck affected points after a change, fault or shift handoff; link the actual approval record.
Record comparison
The scenario and record comparisons are fictional teaching examples, not records of real incidents, measurements, inspections, signatures or approvals.
The boxes are static record prompts, not interactive or saved approvals. A tick does not establish suitability or permission to restart. Record the evidence, person, time and unresolved issues; retain the change history.
| Record | Insufficient | Record checklist |
|---|---|---|
| Evaluate location | "Checked" without target, criteria or result | □ Connections and inflows□ Work and space classification□ Non-entry alternatives□ Rescue capability |
| Inspect blocks | "Checked" without target, criteria or result | □ Block ID and condition□ Insert and rigging fit□ Weight and crane plan□ Level and bearing |
| Authorize entry | "Checked" without target, criteria or result | □ Gas instrument and results□ Permit and entry limits□ Ventilation and isolation□ Attendant contact and rescue |
| Close and handoff | "Checked" without target, criteria or result | □ Exit and tool count□ Cover and traffic state□ Flow restoration sequence□ Future entry restrictions |
8. Site checklist and emergency response
| Check | Result | Person / action |
|---|---|---|
| □ Evaluate location: Connections and inflows | ||
| □ Protect excavation: Competent inspection | ||
| □ Inspect blocks: Block ID and condition | ||
| □ Lower and join: Personnel clear | ||
| □ Authorize entry: Gas instrument and results | ||
| □ Finish and monitor: Work-zone measurements | ||
| □ Evacuate and respond: Entrant accountability | ||
| □ Close and handoff: Exit and tool count | ||
| □ Emergency access and handoff restrictions |
Stop work
Exit immediately for gas alarms, ventilation or communication loss, or changing inflow. Do not enter during block lowering or with unstable support or unverified rescue arrangements.
Emergency response
Evacuate, raise the alarm and activate the prearranged capable rescue service; call 911 as part of that plan. The attendant must not improvise unprotected entry. A dust respirator does not protect against oxygen deficiency. Control the opening and remaining inflow hazards.
9. Sources and review limits
Public-source review: 2026-10-12. Official regulation pages and specific technical references are distinguished below; no agency or manufacturer has approved this content.
| Source | Reviewed scope and limitation |
|---|---|
| OSHA 29 CFR 1926.651 | Excavation conditions, access, utilities and competent-person inspection. |
| OSHA 29 CFR 1926.652 | Excavation protective systems. |
| OSHA 29 CFR 1926.1203 | Construction space evaluation, entry controls and employer coordination. |
| OSHA 29 CFR 1926.1204 | Permit-space program, isolation, entry conditions and atmospheric monitoring requirements with specified exceptions. |
| OSHA 29 CFR 1926.1211 | Rescue capability evaluation, arrangements and retrieval requirements. |
| OSHA State Plans | Official overview of federal and State Plan jurisdiction and differing public-sector coverage, checked 2026-10-12. Individual state rules require a site-specific check. |
No site measurements, equipment manuals for the actual installation, inspection records or signed technical approvals were supplied. Confirm the applicable requirements and actual product instructions before use; record each criterion with its units, source and equipment or work-area ID.
10. PDF guidance and FAQ
PDF A covers basic task controls; B focuses on technical failures; C covers supervision, records and handover. The article has eight stages with four items per main cell; each PDF has six key stages with three items per main cell. P/S/R/A, measurements, confirmations and signatures remain blank for actual site assessment.
Content group
jsa-manhole-assembly
Does a newly built manhole avoid confined-space review?
No. Assess its configuration and actual or potential hazards, not only its age.
Is a normal oxygen reading enough?
No. Assess relevant toxic/flammable hazards, inflow, access, ventilation, monitoring and rescue conditions.
Can the morning reading be reused after a break?
Confirm current conditions and changes under the entry procedure before re-entry; maintain the required monitoring during work.
Should the attendant immediately climb down to a fallen coworker?
No improvised entry. Activate the prepared rescue arrangement and keep unauthorized people out.
Has a professional approved this JSA?
This reference material was written and revised with AI. It has not been verified or approved by a professional. Review by a suitably qualified professional and required site approval are necessary before field use.
11. Revision history and authorship
This reference material was written and revised with AI. It has not been verified or approved by a professional. Review by a suitably qualified professional and required site approval are necessary before field use.
Korean source created 2026-09-19. This US edition adapts the Korean source; earlier editorial revisions do not constitute professional approval of this edition.
| Date | Edition | Change | Review status |
|---|---|---|---|
| 2026-10-12 | 1.0 | US localization: preserve task judgments; replace Korean legal applicability with scoped US references. | AI editorial and output checks; no professional technical approval. |