Tubing for Instrumentation Service

 

 

1. PURPOSE

 

1.1       This engineering standard defines the criteria for selection of instrument tubing, bundled tubing, and electrically traced tubing.

 

 

2. SCOPE

 

2.1       This standard applies to all instrument packages except instrumentation for ultra-high purity service.

 

 

3. RELATED DOCUMENTS

 

3.1      Company Engineering Documents

 

4PS52001A    Copper Tubing, Brass Fittings, and Valves for Instrument Service

 

4PS52002A    Stainless Steel Tubing, Fittings, and Valves for Instrument Service 170 bar g

(2500 psig) Maximum

 

4PS52003A    Stainless Steel Tubing, Fittings, and Valves for Instrument Service 415 bar g

(6000 psig) Maximum

 

4PS52004A    Bundled Tubing for Instrument Service

 

4PS52005A    Electrically Traced Tubing for Instrument Service

 

4API-90641    Stainless Steel Tubing and Fittings for High Pressure Applications up to

206 bar g (3000 psig)

 

 

4. CRITERIA FOR TUBING SELECTION

 

4.1       Copper is the cost-preferred tubing for instrument service. Project scope, process pressure, process temperature, site conditions, such as atmospheric corrosion or customer request, might supersede this preference. Refer to 4PS52001A for additional information.

 

4.2      Stainless steel tubing will be specified when one or more of the conditions in paragraph 4.1 or

4PS52001A are not met. For additional information, refer to 4PS52002A and 4PS52003A with

temperature ranges of -30 to +150°C (-20 to +300°F) and 4API-90641 with temperature ranges of -223 to +148°C (-452 to +300°F).

 

4.3       All process tubing will be 3/8 inch OD. Analyzer sample tubing will be 1/4 inch OD to minimize lag time. Instrument air supply tubing within the last 450 mm (18 in) maximum of a user will be 3/8 inch OD unless otherwise specified by the project scope or customer request.

 

4PS52000A, Rev. 2, Page 2 of 2

 

4.4      Tubing will be specified in coils only. Minimum lengths of 150 m (500 ft) will be selected when

Company is supplying the tubing.

 

4.4       Bundled tubing will be specified when the use results in a lower installation cost over individual tubes. Refer to 4PS52004A for additional information.

 

4.5       Electrically traced tubing will be specified when freeze protection or maintaining a constant temperature is a requirement. Refer to 4PS52005A for additional information.

 

4.6      Nonmetallic tubing shall not be considered for general use unless authorized by Company

Global Operations (GO).