Supply voltage and logic-level margins
The CD4069UBPW: Quiescent current maxes at 1 µA, so the standby power is negligible even in battery-backed designs; the 3.4mA output drive per channel is enough for CMOS fan-out but won't drive a relay directly.
Propagation delay and signal-chain timing
Maximum propagation delay is 50 ns at 15V supply into a 50 pF load — this sets the upper data rate at roughly 10 MHz for a single inverter stage, though cascading six inverters in a ring adds 300 ns of latency end-to-end. The 50pF load capacitance is typical of a short PCB trace plus one CMOS gate input; driving longer traces or multiple loads increases the effective delay beyond the datasheet figure.