A LEGAL REQUIREMENT FOR RELIEF DEVICE DOCUMENTATION
Does your plant have Pressure Relief Devices? Do you also have any of the Highly Hazardous Chemicals listed in OSHA Regulations (Standards – 29 CFR) Process Safety Management of Highly Hazardous Chemicals.-1910.119. This standard requires the employer to have a compilation of written process safety information if the quantity is above the threshold value listed in Appendix A of the standard. This process safety information shall include information pertaining to the hazards of the highly hazardous chemicals used or produced by the process, information pertaining to the technology of the process, and information pertaining to the equipment in the process. Information pertaining to the equipment in the process shall include Relief System design and design basis.
EXPERIENCE DRIVEN DESIGN
Our experience indicates that 25% to 50% of existing relief valves will be inadequately sized or poorly installed. The majority of failures occur because the inlet piping to the relief valve is too long or too small. This results in a pressure drop above the ASME 3% limit and means that the pressure in the equipment will rise above the MAWP beyond the allowance provided by ASME. The second largest component of failures is pressure drop in the outlet piping exceeding the ASME 10% limit. This results in valve chatter which reduces the relieving capacity of the system and can easily damage the valve enough to prevent complete reseating.
SOFTWARE DRIVEN CALCULATIONS
Our spreadsheet minimizes the time required to produce the calculations and minimizes errors. Our software, with a five-year track record, provides an analysis of each pressure / vacuum relief device (valves, rupture disks, and vents) based on the appropriate code (ASME, NFPA, API, ASHRAE) and over/ under pressure situation. It can handle gases, liquids and two phase flow.
What ORION ENGINEERING’S Analysis considers:
Our Calculations include:
Our Output Documentation
Complete documentation is provided for each device as required by PSM.
Documentation includes all calculations, a sketch of the proposed or redesigned piping/equipment protected by the device, the design basis, the worst case cause of relief, the required / selected relief device orifice area, a relief device spec sheet, and supporting catalog cuts. The output can easily be tailored to your relief record form.
Orion Engineeringis pleased to offer this service to our industrial clients and would be happy to provide a written proposal for your specific situation.
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I have a number of similar systems and a lot of devices.
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