Fike’s ValveGuard Strategy

In industries where the safe operation of pressurised systems is paramount, engineers and safety professionals continually seek solutions to mitigate potential risks. One such approach involves employing a rupture disc in series with a relief valve. This configuration enhances process safety by providing a reliable and efficient means of pressure relief.

What are the Benefits:

Many industrial processing companies have found that installing rupture discs upstream of pressure relief valves are an effective way of reducing overall leakage.

Rupture discs are effectively leak tight, single-use metallic pressure relief devices engineered to open when the process pressure reaches the disc’s set burst pressure. In these upstream assemblies, the process media only reaches isolated pressure relief valves when the rupture disc activates. The combination of pressure relief valves and upstream rupture discs will largely eliminate fugitive emissions. At the same time, the safety of the installation against overpressure conditions remains at the required level.

In addition to the improved emissions control, this isolation may reduce the total cost of ownership of expensive pressure relief valves. During normal operation, the valve is protected from corrosive or viscous media, potentially resulting in less cleaning, maintenance, downtime and expensive valve trim.

Finally, upstream rupture discs can extend the service life of pressure relief valves, reducing the loss of production time needed for removal and re-assembling of the device. This is possible because the added rupture disc allows for ‘in-situ’ testing of the pressure relief valve (without the need to uninstall it) by demonstrating its unchanged performance. A limited volume is created between the rupture disc and valve inlet, where isolated pressure may be introduced to measure and register as evidence of acceptable valve performance.

Selection and Installation Considerations:

To safely realise the benefits of installing rupture discs upstream of pressure relief valves, several measures must be considered.

The rupture disc should not impede or interfere with the operation of the pressure relief valve. To achieve this, the rupture disc must be ‘non-fragmenting,’ so upon activation, loose parts do not enter the valve and obstruct the orifice or restrict the valve from closing. A sufficient distance between the rupture disc and the valve seat is required to prevent obstruction. However, the rupture disc must still be installed close enough to the valve to avoid the creation of reflective pressure waves during the opening of the disc. When installing rupture disc devices upstream of relief valves, the rupture disc size should be at least the same nominal size as the inlet of the relief valve. Additionally, the rated relief capacity of the valve, as stated by the manufacturer, is to be reduced by 10 percent, or to the certified combination capacity value (where certified by a recognised third party). Finally, the set pressure of the rupture disc device is typically set at the same pressure as the PRV, which itself is set in accordance with the applicable legislative standards and guidelines.

Search related articles:   Fike Europe BV - UK OfficeIssue 96Bursting Disks