Ownership of mobile platforms
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At a height of 5 meters on the tower, there is a nozzle about 400 millimeters in diameter, directly connected to an always-open disc valve; it is located in isolation and is not used frequently, so no platform or stairs have been designed for it. During testing, the workers use a bamboo ladder hung nearby to climb up and operate it. It sways back and forth, which is quite scary. The testing did not go smoothly; the workers kept opening and closing the butterfly valve over and over again, cursing loudly. Some people say a platform should be installed in this place, while others say it’s not necessary and a mobile platform will suffice. The project is EPC; who should manufacture the mobile platform?
If the drawings at the design stage undergo final joint review by both parties and are signed off with no objections. If additional facilities need to be added during later use, the contractor is willing to cover the extra costs; if they are not willing to do so, the owner will have to carry out those temporary additional tasks on their own. (The key is to check whether such detailed contractual terms are specified in the EPC supplementary clauses.)
Such detailed contract terms are not specified in the EPC supplementary clauses, but the EPC party provides the process package. Based on relevant standards, the designer believes that a fixed platform is not necessary. The drawings at the design stage were finally reviewed by both parties and signed off with no objections.
The EPC contract should specify under what circumstances or in which areas operational or maintenance platforms should be installed, as this can lead to disputes. EPC may not be aware of the operating and maintenance conditions.
This kind of thing falls under technical specifications; it’s usually provided by design firms, and the owner doesn’t pay attention to such detailed aspects
During the three checks and four confirmations, no one raised it either.
It should be designed so that EPC personnel can go and give it a try; the specifications state that valves require an operating platform
I think the design department is right; a platform can certainly be used to solve this issue, but why not simply use electric or pneumatic butterfly valves?
The platform affects the channel. Electric or pneumatic butterfly valves are extremely expensive, have a long procurement cycle, and it’s too late to order them now. If the test run hadn’t gone smoothly, no one would have paid attention to this normally open valve.
This post was last edited by Liushui Zhiyun shine on 2019-12-11 at 14:10. For information on where to locate platforms and ladders, refer to HG/T 20546-2009 Specifications for the Layout Design of Chemical Plant Equipment, section 4.1.1 (see attachment). However, the text does not explain what is covered by the term “operation” in it. Company L once had such a rule. Company S requires a higher level of detail than specified in HG/T 20546: To facilitate production operations and maintenance, platforms should generally be provided at elevations above 2000 mm for all process equipment such as manholes, inlet and outlet valves, level gauges, control valves, valves that are used frequently, pressure gauges, thermocouples, etc. In special cases, it must also be ensured that operators and maintenance personnel can carry out operations and maintenance. Both Company L and Company S are leaders in their industry; the design team referred to Company S’s guidelines, which were subsequently approved by the EPC contractor and the project owner.