Instrument air supply pipeline
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I need technical assistance; currently we are working on-site, and the gas supply pipes are made of galvanized steel pipes. The air source elbows, tees, reducers, and pipe clamps are made of cast iron fittings – is it acceptable to install them in this way? Is there any standard that requires this?
Anyway, that’s how we use it: L
There are significant differences among various companies regarding the materials used for gas supply pipelines. Initially, galvanized pipes and galvanized fittings were commonly used, but this approach led to frequent leaks, as cast iron fittings lacked the strength needed and tended to break and leak. Later, steel galvanized fittings were adopted, which provided a slightly better result than the previous option. Now, many manufacturers, in order to address the issue of leaks in the gas supply pipelines, replace all such pipelines with 304SS material and use welding for connections, thereby completely eliminating problems such as shutdowns and minor repairs caused by gas leaks.
HG_T20510-2014, the Design Specification for Instrument Air Supply, states in section 7.5.2 that when galvanized steel pipes are used in the air supply system, galvanized threaded fittings should be employed; welded connections shall not be used. 8.1.1 The selection of piping material can be determined according to the pipe specifications for the specific project.
SHT 3020-2013 Code for Design of Gas Supply for Petrochemical Instruments 6.1.1 Galvanized steel pipes or stainless steel pipes can be used for the main and branch gas supply pipes on-site. The connecting fittings should be of the same material as the pipeline.
This post was last edited by myface on 2018-8-16 at 16:24. This seems to be a rather general question; generally, one needs to consider the applicable scenarios, the properties of the medium, the pressure level, and the type of connection—such as welding or threading—to determine whether different materials meet the requirements. The following standards can be used as references: GB 50093-2013 Code for Construction and Quality Acceptance of Automation Instrumentation Projects; GB 50236-2011 Code for Construction of Field Equipment and Industrial Pipeline Welding Projects; HG 20512-2014 Code for Design of Instrument Piping and Wiring
It can be installed in this way, but make sure the installation quality is good.
According to the standards, galvanized pipe fittings should be used for connection; welding in this way does not ensure construction quality
Just welded it together; everything was designed to be made of 304 stainless steel, but it was a hassle due to the poor threading skills of the workers on site.
All 304 material – isn’t it expensive for long distances?
All 304 material – isn’t it expensive for long distances?