Can an emergency shut-off valve not replace remote control for operating valves?
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Non-conformities identified by the Safety Supervision Bureau: Emergency shut-off valves are used in place of remotely controlled valves for liquefied gas cylinders. With so many bans in place, which one is this violating?
The last edit to this post was made by Hansonwen on 2018-9-13 at 17:52. In principle, the control systems for emergency shut-off valves and remotely controlled on/off valves should be different; remotely controlled on/off valves are generally controlled by a DCS, and their operation is intended to meet the requirements regarding process flow in and out； The emergency shut-off valve should be independent and controlled by a separate ESD or SIS system; its operation occurs only under accident conditions such as high/low liquid levels, power outages, gas outages, or fires. The functions of the two valves need to be distinguished: one is for process use, and the other is for safety purposes. Reference can be made to the provisions on instrument configuration in SHT3007-2014 \"Design Code for Tank Areas in Petrochemical Storage and Transportation Systems\" and SHT3184-2017 \"Design Code for Automation Systems in Petrochemical Tank Areas\"
Agree with the analysis above; the tank farm requires a separate SIS.
Previously, it was usually a manual valve plus a shut-off valve; if an automated control valve was added as well, would that mean there would be three valves for the tank’s inlet and outlet? Manual valves are used to prevent failures in cut-off valves; can they be eliminated now?
During operation, the manual valve should be kept fully open, and it should be closed completely when shutdown – this isn’t difficult at all. For normal control, remote adjustment is used; in emergency situations, the emergency shut-off valve takes action automatically, with safety being the top priority
These days, it is usually a separate automatic shut-off valve, and the shut-off valve can also be operated manually
In situations where an emergency shut-off valve is required, it isn’t necessarily necessary to use a SIS system. However, it needs to have both remote and on-site manual control functions.
Interim Provisions on the Supervision and Management of Major Hazard Sources of Hazardous Chemicals, commonly referred to as Order No. 40, Article 13: “Emergency shut-off devices shall be installed for key facilities within major hazard sources, such as toxic gases, highly toxic liquids, and flammable gases.” “For major hazard sources of grade 1 or 2 involving toxic gases, liquefied gases, or highly toxic liquids, an independent Safety Instrumented System (SIS) must be installed.” Literally speaking, for those required to install emergency shutdown devices, if they are not classified as major hazard sources of level 1 or 2, it is not necessarily required to install a SIS.