What is the safety valve accumulation limit for a single device?

• A. 5%
• B. 10%
• C. 15%
• D. 20%

Answer: (B)

The key idea is how much the pressure can rise above the valve’s set pressure while the relief device is discharging. This rise is called accumulation. For a single safety valve or relief device, the standard allowed accumulation is 10% of the set pressure. That means during relief, the system pressure can climb up to set pressure plus 10%, but no more. This limit provides a safe margin to prevent excessive overpressure while ensuring the device can relieve quickly enough.

Choosing a smaller value (like 5%) would impose a tighter limit that could risk nuisance relief or mis-tuning of the system, while larger values (15% or 20%) could expose components to higher transient pressures before full relief capacity kicks in. Therefore, 10% is the appropriate and standard limit for a single device.