Confined Space Hazard Control Matrix Field Reference
| Hazard | Protective Device / Control | OSHA / Standard Reference |
|---|---|---|
| Oxygen Deficiency (<19.5%) or Enrichment (>23.5%) | Continuous atmospheric monitoring; forced-air ventilation; supplied-air respirator or SCBA as required | 29 CFR 1910.146(d)(5)(iii); 29 CFR 1910.134 |
| Flammable Gas or Vapor (>10% LEL) | Continuous monitoring; ventilation to maintain <10% LEL; intrinsically safe tools/equipment | 29 CFR 1910.146(d)(5)(iii); 29 CFR 1910.307 |
| Toxic Atmosphere (above PEL or IDLH) | Ventilation; continuous monitoring; respiratory protection (APR, PAPR, SAR, SCBA) per hazard | 29 CFR 1910.146(d)(5)(iii); 29 CFR 1910.134 |
| Engulfment in Flowable Solids or Liquids | Isolation (blanking, blinding, disconnecting lines); drain/remove material; no-entry until eliminated | 29 CFR 1910.146(b); 29 CFR 1910.146(d)(3) |
| Mechanical/Energy Hazards | Lockout/tagout; block or secure moving parts; release stored energy | 29 CFR 1910.146(d)(3); 29 CFR 1910.147 |
| Falls During Entry/Exit | Full-body harness; lifeline; tripod or davit arm retrieval system (enable non-entry rescue) | 29 CFR 1910.146(k)(3); ANSI Z359 |
| Noise >85 dBA | Hearing protection; administrative controls; quieter equipment selection | 29 CFR 1910.95 |
| Chemical Splash or Contact | Chemical-resistant gloves/boots/clothing; eye/face protection per SDS and task | 29 CFR 1910.132; 1910.133; 1910.138 |
| Heat Stress | Ventilation; hydration; work/rest cycles; cooling PPE; monitoring for symptoms | OSHA Technical Manual Section III: Chapter 4 |
• Use this matrix with your written permit-required confined space program, entry permits, and air monitoring logs.
• Control hierarchy: eliminate or isolate hazards first, then engineering controls, then administrative controls and PPE.
• Always follow manufacturer instructions and company policies.
