🔹 Spring Return Actuators (Fail-Safe Required)
Specs usually call for spring return when:
a. Fire & smoke dampers (UL555/UL555S listed)
b. Life safety systems where a defined fail position is mandatory
c. Exhaust or fresh air dampers in pressurization systems
d. Critical valves (chilled water, hot water, condenser water) that must e. close/open on power failure
f. Codes/standards (ASHRAE, UL, NFPA) require a safe position

🔹 Non-Spring Return Actuators (Fail-Safe Not Required)
Specs allow non-spring return in:
a. Standard HVAC dampers for comfort control
b. Mixing or modulating dampers where power loss does not compromise safety
c. Valves in secondary loops where fail position is not critical
d. Energy management applications where cost-efficiency is prioritized

👉 Spec Compliance Tip:
Check Division 23 (HVAC) and Life-Safety sections of the spec.

f the sequence of operation says “damper shall fail closed” or “valve shall fail open” → Spring return is mandatory.

If no fail-safe is mentioned → Non-spring return is acceptable.

Rule of Thumb: Safety-driven = Spring Return. Comfort-driven = Non-Spring Return.