HVAC Psychrometric Chart Practice Questions
Fire Protection in HVAC Systems
Fire Protection in HVAC Systems
Last Updated: [Current Date]
1. Fire Dampers & Smoke Dampers
| Type |
Location |
Activation |
Testing Frequency |
| Fire Damper |
Fire-rated walls, floors, partitions |
Fusible link (165°F/74°C typical) |
Annually |
| Smoke Damper |
Smoke barriers, elevator shafts |
Smoke detector signal |
Semi-annually |
| Combination Damper |
Atriums, high-risk zones |
Smoke detector + heat |
Quarterly |
⚠ CRITICAL: Never block damper access panels. Ensure proper labeling for maintenance.
2. Ductwork Fire Protection
| Requirement |
Standard |
Details |
| Fire-Rated Ducts |
UL 555S |
Required for shafts penetrating fire barriers |
| Duct Insulation |
NFPA 90A |
Must be non-combustible (flame spread ≤25) |
| Grease Ducts |
NFPA 96 |
Must have 18" clearance from combustibles |
⚠ WARNING: Flexible duct connectors cannot be used as fire dampers.
3. Smoke Control Systems
| System Type |
Application |
Key Requirement |
| Stairwell Pressurization |
High-rise buildings |
0.05-0.10 in. w.g. pressure differential |
| Zone Smoke Control |
Atriums, large spaces |
Automatic activation by smoke detectors |
| Exhaust Systems |
Parking garages, kitchens |
6 air changes per hour (ACH) minimum |
✓ BEST PRACTICE: Test smoke control systems under both automatic and manual modes annually.
4. Clearance Requirements
- Combustibles: 18" minimum from furnaces/boilers
- Electrical: 3' clearance from HVAC equipment
- Access: 30" clearance for maintenance in front of equipment
5. Maintenance Checklist
| Item |
Frequency |
Action |
| Fire/Smoke Dampers |
Annually |
Operational test, visual inspection |
| Ductwork |
Biannually |
Inspect for damage, proper sealing |
| Smoke Detectors |
Quarterly |
Function test, clean as needed |
| Grease Ducts |
Per NFPA 96 |
Professional cleaning |
Reference Standards: NFPA 90A, NFPA 92, NFPA 96, IMC Chapter 6, UL 555/555S