Student Material 001: Respiratory Protection and Ventilation Reference Guide
Material ID: U10M3-MAT-001
Purpose: Quick reference for respirator selection, fit checking, filter schedules, and ventilation monitoring
Respirator Selection Guide
| Blasting Scenario |
Hazard Level |
Required APF |
Recommended Respirator |
| Cabinet blasting, LEV functional |
Low |
10 |
N95 filtering facepiece or P100 half-face |
| Cabinet blasting, LEV marginal |
Moderate |
10–50 |
P100 half-face or full-face elastomeric |
| Media change / filter maintenance |
Moderate |
10 |
P100 half-face minimum |
| Cabinet blasting, LEV failed |
High |
50+ |
Full-face elastomeric + P100; stop work |
| Open blasting (any) |
Very High |
1000 |
Supplied Air Respirator with blasting hood |
| Unknown contaminants / lead paint |
Variable |
50+ |
Full-face + P100; consider SAR |
Assigned Protection Factors (APF) Quick Reference
| Respirator Type |
APF |
Maximum Use Concentration |
| N95 Filtering Facepiece |
10 |
10x exposure limit |
| P100 Half-Face Elastomeric |
10 |
10x exposure limit |
| Full-Face Elastomeric (P100) |
50 |
50x exposure limit |
| PAPR Half-Face |
50 |
50x exposure limit |
| PAPR Loose-Fitting Hood |
25 |
25x exposure limit |
| PAPR Full-Face/Helmet |
1000 |
1000x exposure limit |
| SAR Half-Face |
50 |
50x exposure limit |
| SAR Full-Face |
1000 |
1000x exposure limit |
| SAR with Blasting Hood |
1000 |
1000x exposure limit |
User Seal Check Procedure (Quick Reference)
Positive Pressure Check:
1. Cover exhalation valve
2. Exhale gently
3. Facepiece should puff outward
4. Hold 10 seconds — no air escape at edges
5. FAIL = air escapes → readjust straps
Negative Pressure Check:
1. Cover both filter cartridges
2. Inhale gently
3. Facepiece should collapse inward
4. Hold 10 seconds — facepiece stays collapsed
5. FAIL = facepiece springs back → readjust or resize
Filter Replacement Guide
| Filter Type |
Replace When |
Maximum Use Life |
| N95 disposable |
Soiled, damaged, wet, or breathing resistance increases |
8 hours or one shift |
| P100 cartridge |
Breathing resistance increases noticeably |
40 hours or 30 days (whichever first) |
| Combination (OV/P100) |
Organic vapor breakthrough OR breathing resistance |
Per manufacturer schedule |
| HEPA (PAPR) |
ΔP increases on PAPR unit OR per schedule |
Per manufacturer schedule |
Ventilation System Monitoring Checklist
| Parameter |
How to Measure |
Acceptable Range |
Action If Out of Range |
| Filter ΔP |
Read gauge on dust collector |
0.5–4" WC (varies by mfr) |
Replace filters if >4" WC |
| Capture velocity at openings |
Smoke tube or velometer |
≥200 fpm inward |
Check ductwork, fan, filters |
| Duct transport velocity |
Pitot tube traverse |
≥3500 fpm |
Increase fan speed or resize duct |
| Cabinet containment |
Smoke tube at seals |
All smoke drawn inward |
Repair seals, check collector |
| Dust collector bin level |
Visual inspection |
<75% full |
Empty bin |
| Fan belt condition |
Visual + tension check |
No cracks, proper tension |
Replace belt |
Common Exposure Limits for Blasting Materials
| Substance |
OSHA PEL (8-hr TWA) |
NIOSH REL |
ACGIH TLV |
| Crystalline silica (respirable) |
50 μg/m³ |
50 μg/m³ |
25 μg/m³ |
| Aluminum oxide (respirable) |
5 mg/m³ |
5 mg/m³ |
1 mg/m³ |
| Garnet (as PNOS, respirable) |
5 mg/m³ |
— |
3 mg/m³ |
| Glass bead (as PNOS, respirable) |
5 mg/m³ |
— |
3 mg/m³ |
| Total particulate (PNOS) |
15 mg/m³ |
— |
10 mg/m³ |
| Lead (dust) |
50 μg/m³ |
50 μg/m³ |
50 μg/m³ |
| Cadmium (dust) |
5 μg/m³ |
Lowest feasible |
10 μg/m³ |
Last Updated: 2026-03-19