Slide 002: Respiratory Protection Selection and Use¶
Slide Visual¶
Slide Overview¶
This slide covers the hierarchy of respiratory protection, how to select the appropriate level for different blasting scenarios, and proper donning, seal check, and maintenance procedures.
Instruction Notes¶
Respiratory Protection Hierarchy¶
OSHA's hierarchy prioritizes engineering controls over PPE: 1. Elimination: Use non-dust-generating processes when possible 2. Engineering controls: Enclosed cabinets with local exhaust ventilation 3. Administrative controls: Limit exposure time, rotate workers 4. PPE (respirators): Last line of defense โ supplements, not replaces, other controls
Respirator Types and Protection Factors¶
| Respirator Type | APF | Best For | Limitations |
|---|---|---|---|
| N95 Filtering Facepiece | 10 | Cabinet blasting with functional LEV | Disposable, no oil resistance |
| P100 Half-Face Elastomeric | 10 | Extended cabinet work, filter changes | Requires fit testing |
| Full-Face Elastomeric | 50 | High-dust situations, unknown contaminants | Requires fit testing, higher cost |
| PAPR (Half/Full-Face) | 25/1000 | Extended work, comfort in heat | Battery powered, maintenance |
| Supplied Air (SAR) + Hood | 1000 | Open blasting, extremely high concentrations | Air supply required, mobility limited |
| SCBA | 10,000 | IDLH atmospheres, emergency response | Heavy, limited air supply |
Selecting the Right Respirator¶
Calculate Required Protection Factor: RPF = Workplace Concentration รท Exposure Limit
Example: Airborne aluminum oxide at 30 mg/mยณ (respirable), ACGIH TLV = 1 mg/mยณ RPF = 30 รท 1 = 30 โ Need APF โฅ 30 โ Full-face respirator (APF 50) or PAPR
For cabinet blasting with functional dust collection: workplace concentration is typically 0.5โ3 mg/mยณ โ N95 (APF 10) is adequate for most operations.
Proper Use Procedures¶
Donning a Half-Face Respirator: 1. Inspect respirator: check straps, valves, gaskets, filter seat 2. Place chin in cup, pull harness over head 3. Adjust lower straps first, then upper straps โ snug but not overtight 4. Perform user seal check: - Positive pressure: Cover exhalation valve, exhale gently. Face should puff slightly. No leaks at edges. - Negative pressure: Cover filter cartridges, inhale. Face should collapse slightly and hold for 10 seconds. 5. If seal check fails: readjust straps or try different respirator size/model
Facial Hair Rule: Users must be clean-shaven where the respirator seals against the face. No exceptions โ even one day of stubble compromises the seal.
Filter/Cartridge Selection¶
- N-series: Not oil resistant. Use for dry particulates (most blasting dust)
- R-series: Resistant to oil. Use when oil mist is present
- P-series: Oil-proof. Use when oil aerosols are present
- 95/99/100: 95%, 99%, 99.97% minimum filtration efficiency
For abrasive blasting: P100 is the gold standard. N95 is acceptable for cabinet work with LEV.
Key Talking Points¶
- A respirator only works if it fits and seals โ fit testing is not optional
- The APF number tells you how much protection the respirator provides
- Facial hair is an absolute disqualifier for tight-fitting respirators
- Cabinet dust collection reduces but does not eliminate respiratory exposure
Learning Objectives (Concept Check)¶
- Select the appropriate respirator type based on hazard assessment and APF calculation
- Demonstrate proper donning and user seal check procedures
- Explain why facial hair compromises respirator effectiveness
Last Updated: 2026-03-19