Thursday, January 19, 2017

Protecting Pressure Relief Valves and Safety Relief Valves

scored rupture disc
A rupture disc can provide PRV isolation
Safety and pressure relief valves are common elements of any pressurized system. Their general purpose is to stop system pressure from exceeding a preset value, preventing uncontrolled events that could result in damage to personnel, environment, or assets. Their operating principle and construction are comparatively simple and well understood.

Long term exposure of a relief valve to any number of media can result in corrosion, material buildup, or other conditions which may shorten the useful life of the valve, or worse, impair its proper operation. This excessive wear will increase the ongoing cost of maintaining or replacing a prematurely worn valve. One other aspect of relief valves can be the reduction in their seal integrity or force as the system pressure approaches the setpoint. This could possibly lead to fugitive emissions, an undesirable condition.

A reasonable solution is posed by Fike, globally recognized leader in fire, explosion, and overpressure protection. Isolating a relief or safety valve from the process media through the installation of a rupture disc upstream of the valve inlet will eliminate exposure of the costly valve to effects of the media. It is necessary to establish proper rating and selection for the rupture disc to avoid any impairment of the overall operation of the relief valve, but the selection criteria are not complex. A number of benefits can accrue with this concept.

  • Avoid purchase of relief valves manufactured from exotic materials to accommodate exposure to corrosive media. Rupture disc provides isolation of the valve from the media.
  • Eliminate fugitive emissions at the relief valve. Rupture discs, when properly installed, are leak free and bubble tight.
  • Relief valve inventory can be evaluated for reduction.
  • Longer valve life.
  • Less downtime.
The additional cost for the rupture disc enhancement can have a reasonable payback period, with all factors considered. In any case, the rupture disc protection makes for a cleaner relief valve installation.

Rupture discs and holders are available in sizes and materials for most applications. Share your ideas with a product specialist, combining your process knowledge with their product application expertise to develop an effective solution.