HVAC Psychrometric Chart Practice Questions Fire Protection Plumbing Quick Reference

Fire Protection Plumbing Quick Reference

1. Pipe Materials & Applications

Material Pressure Rating Common Uses Joining Method
Steel (Schedule 40) 150-300 psi Main supply lines, standpipes Grooved, threaded, welded
CPVC 100-175 psi Residential sprinklers Solvent cement
Copper (Type K) 100-200 psi Small systems, corrosive environments Soldered, pressed
PEX 80-160 psi Limited residential applications Crimp fittings
⚠ CRITICAL: Never mix pipe materials without proper dielectric unions to prevent galvanic corrosion.

2. Water Supply Requirements

System Type Minimum Pressure Duration Storage Requirements
Standpipe 100 psi at top outlet 30 minutes 500 gal minimum
Automatic Sprinkler 7 psi at remote head 30-90 minutes Per hydraulic calc
Fire Pump Supply 20 psi suction Full demand duration No vortexing

3. Backflow Prevention

Device Type Application Test Frequency
Double Check Valve Low hazard connections Annually
Reduced Pressure Zone (RPZ) High hazard connections Semi-annually
Pressure Vacuum Breaker Non-potable systems Annually
✓ BEST PRACTICE: Install test ports on both sides of backflow preventers for proper testing.

4. Standpipe System Requirements

Class Outlet Size Hose Connection Pressure Limit
I 2.5" Fire Dept use only 100 psi max
II 1.5" Occupant use 65 psi max
III 1.5" & 2.5" Dual purpose 100 psi max

5. Inspection & Maintenance

⚠ WARNING: Never use galvanized pipe downstream of fire pumps (risk of dezincification).

6. Drainage Requirements

Component Slope Discharge Location
Main Drains 1% minimum Floor drain with air gap
Valve Drainage Positive flow Visible discharge
Test Headers N/A Outside or approved drain

Reference Standards: NFPA 13 (Sprinklers), NFPA 14 (Standpipes), NFPA 24 (Private Service Mains), IPC Chapter 9