Licensing issues for special equipment manufacturing and reconstruction units
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During the recent review for renewing the unit’s filling certificate, it was required that pipeline safety relief devices be installed in the liquid-phase enclosed sections between valves. The review experts suggested that safety pressure relief devices must be added in many areas within the station, such as the section between the emergency shut-off valve and the control valve of the loading/unloading dip pipes; they also recommended that safety valves be installed in the section between the boundary valve and the emergency shut-off valve for the pipelines that enter the station from outside. It seems that without clear explanations in this clause, it’s easy to go overboard in taking corrective actions. We’ve installed a valve on each end of the control valve on our pump exports, solely for the purpose of facilitating maintenance; these valves are not closed under normal circumstances. Now we’re supposed to add two more safety valves – it’s frustrating! I’m not sure whether, if I designate the valves at both ends of the pipeline as normally open valves, label them as such, and apply locks, it can be considered that the pipeline is not closed, and thus no pressure relief device is necessary I wonder if any of you sailors have encountered this situation; I would appreciate any advice on how to resolve it. Thank you.
Find out which regulations, rules, or standards require seeking advice from experts; then locate the relevant provisions for examination, and determine what should be done
The expert opinion comes from the \"Rules for Licensing Special Equipment Production and Filling Units\", which states that \"a pipeline safety pressure relief device shall be installed in the liquid-phase enclosed section between valves.\" However, regarding the situation where the valves at both ends are normally open and only closed during maintenance, the specifications do not provide detailed explanations on whether this is acceptable. These days I checked other standards; the \"Regulations on Safety Inspection of Pressure Pipelines – Industrial Pipelines\" state that \"in pipeline systems where thermal expansion or vaporization occurs due to the closure of the valves at both ends, influenced by environmental temperature, sunlight, or heating, safety pressure relief devices must be installed.\" The \"Code for Fire Protection Design of Petrochemical Enterprises\" also specifies that \"for pipelines carrying liquefied hydrocarbons, Class A and B liquids, where the valves at both ends are closed and external factors may cause an increase in the pressure of the fluid, pressure relief safety measures must be taken.\" ” Based on these specifications, can we avoid installing an additional safety pressure relief device by using the approach of keeping our previous valve in the open position and applying a lock?
Based on your description, there is a situation in which both valves of your pipeline are closed; although this happens not often, it does occur from time to time. Indeed, it is necessary to install a relief device in accordance with the several standards you mentioned. The principle is simple: as long as there is a situation where two valves are closed, hazardous materials will be trapped in a space, which can lead to the risk of pressure buildup (especially with liquefied hydrocarbons, liquefied gases, etc.). Such accidents have happened before. Unless the hazardous medium has been properly cleaned and replaced before shutting off the dual valves. Personal opinion, for reference only: handshake
Thank you for your feedback. Following coordination and discussions among leaders and experts, it was determined that a safety pressure relief device needed to be installed on the loading flexible pipe. The main pipeline section at the boundary agreed to our approach of installing an always-open valve and applying a lock to keep it in that position; before closing the valve, it was necessary to completely remove any liquefied gas from that pipeline section.
Thank you for your feedback. Following coordination and discussions among leaders and experts, it was determined that a safety pressure relief device needed to be installed on the loading flexible pipe. The main pipeline section at the boundary agreed to our approach of installing an always-open valve and applying a lock to keep it in that position; before closing the valve, it was necessary to completely remove any liquefied gas from that pipeline section.