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Safety Elements for Gas Installations
Introduction
Pressure relief devices are elements used in any container that contains gases or liquids at pressures greater than atmospheric that prevent the container from breaking due to excessive pressure increases.
These safety features are commonly used on any pressure vessel. They can be found in equipment in the chemical, food, gas, oil, energy, etc. industries. or in elements for domestic use, such as electric water heaters.
Function
Its function is to protect the different equipment (vessels, heat exchangers, pumps, compressors "Compressor (machine), etc.) against a high increase in pressure, generally due to a failure in the process.
They act by releasing the fluid (liquid or gas) that circulates or is stored in the protected equipment, either to the atmosphere or to a pipe or collection container specially designed for this function.
Guys
Several types of devices can be found: pressure safety valves (PSV), vacuum breaker valves, rupture disks (RD).
As a general rule, the device must act, that is, allow the fluid to escape from the container, at a pressure lower than the failure pressure of the container. They must also allow the passage of a fluid flow rate such that it ensures the immediate decrease in pressure in the container under any operating condition of the system in question.
Examples of use
For example, in a tank that receives air from a compressor "Compressor (machine)"), the safety valve must open at a pressure lower than the burst pressure of the tank and must allow the output of a flow rate equal to or greater than the flow rate that the compressor is capable of delivering.
When rupture discs are installed below PSV's, the asme code requires that a pressure gauge, needle valve, free vent, or axiometer gauge be installed in the space between the rupture disc and the PSV. If a pressure switch is used to activate an alarm, the setting shall not exceed 5% of the burst pressure specified for the rupture disc.
When rupture discs are installed, disc holders must be provided and installed with locks to prevent installing the discs in reverse. Rupture discs will be installed only in disc holders specifically approved for the disc to be used. In general, the disc holder will be the same brand as the disc to be used. Disc holders of another brand should be used only with approval of the plant engineer.
Safety Elements for Gas Installations
Introduction
Pressure relief devices are elements used in any container that contains gases or liquids at pressures greater than atmospheric that prevent the container from breaking due to excessive pressure increases.
These safety features are commonly used on any pressure vessel. They can be found in equipment in the chemical, food, gas, oil, energy, etc. industries. or in elements for domestic use, such as electric water heaters.
Function
Its function is to protect the different equipment (vessels, heat exchangers, pumps, compressors "Compressor (machine), etc.) against a high increase in pressure, generally due to a failure in the process.
They act by releasing the fluid (liquid or gas) that circulates or is stored in the protected equipment, either to the atmosphere or to a pipe or collection container specially designed for this function.
Guys
Several types of devices can be found: pressure safety valves (PSV), vacuum breaker valves, rupture disks (RD).
As a general rule, the device must act, that is, allow the fluid to escape from the container, at a pressure lower than the failure pressure of the container. They must also allow the passage of a fluid flow rate such that it ensures the immediate decrease in pressure in the container under any operating condition of the system in question.
Examples of use
For example, in a tank that receives air from a compressor "Compressor (machine)"), the safety valve must open at a pressure lower than the burst pressure of the tank and must allow the output of a flow rate equal to or greater than the flow rate that the compressor is capable of delivering.
When rupture discs are installed below PSV's, the requires that a pressure gauge, needle valve, free vent, or axiometer gauge be installed in the space between the rupture disc and the PSV. If a pressure switch is used to activate an alarm, the setting shall not exceed 5% of the burst pressure specified for the rupture disc.
Users should be warned that the rupture disc will not burst at its design pressure if back pressure is generated between the disc and the safety valve or safety relief valve, resulting in leakage of the rupture disc due to corrosion or other cause. Adequate monitoring procedures should be in place in the field to detect any backpressure before it becomes a problem.
Some rupture disc installations will require the use of gaskets to seal both sides of the disc. Standard pipe gaskets may not be useful for rupture disc installations.
The packing material should be selected in such a way as to provide metal-to-metal seal of the disc and disc holder without showing slippage. The disc manufacturer and plant group should be consulted to ensure proper packaging is being used.
In processes in which several rupture discs vent to a collecting system, instrumentation must be available to indicate which rupture disc is open. This is particularly important in bach processes where after some period the “evidence” shown by an axiometer gauge may not be present (for example, all pressures tend to equalize after the system has a shutdown trip). Pressure sensors and temperature measuring elements connected to a recorder or alarm may be required to “capture” the event when this occurs.[1].
If there is a possibility of freezing of the PRD, protection must be provided by either tracing and/or insulation. This can be especially critical in pilot-operated PRDs.
Find more "Safety Elements for Gas Installations" in the following countries:
When rupture discs are installed, disc holders must be provided and installed with locks to prevent installing the discs in reverse. Rupture discs will be installed only in disc holders specifically approved for the disc to be used. In general, the disc holder will be the same brand as the disc to be used. Disc holders of another brand should be used only with approval of the plant engineer.
Users should be warned that the rupture disc will not burst at its design pressure if back pressure is generated between the disc and the safety valve or safety relief valve, resulting in leakage of the rupture disc due to corrosion or other cause. Adequate monitoring procedures should be in place in the field to detect any backpressure before it becomes a problem.
Some rupture disc installations will require the use of gaskets to seal both sides of the disc. Standard pipe gaskets may not be useful for rupture disc installations.
The packing material should be selected in such a way as to provide metal-to-metal seal of the disc and disc holder without showing slippage. The disc manufacturer and plant group should be consulted to ensure proper packaging is being used.
In processes in which several rupture discs vent to a collecting system, instrumentation must be available to indicate which rupture disc is open. This is particularly important in bach processes where after some period the “evidence” shown by an axiometer gauge may not be present (for example, all pressures tend to equalize after the system has a shutdown trip). Pressure sensors and temperature measuring elements connected to a recorder or alarm may be required to “capture” the event when this occurs.[1].
If there is a possibility of freezing of the PRD, protection must be provided by either tracing and/or insulation. This can be especially critical in pilot-operated PRDs.
Find more "Safety Elements for Gas Installations" in the following countries: