- PURPOSE
1.1 This engineering standard defines the criteria for the selection of bundled tubing used for instrument service.
- SCOPE
2.1 This standard applies to all field instrument packages, except instrumentation for ultra-high purity service.
- RELATED DOCUMENTS
3.3 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
- GENERAL
4.1 The use of copper tube bundles shall only be considered for runs in excess of 16 m (50 ft).
Stainless steel tube bundles shall be used for any run in excess of 6 m (20 ft) if at least 6 m
(100 ft) of each size will be installed over the entire job.
4.2 Spare tubes are not required in tube bundles, except in those cases where there is a probable future application. The standard number of tubes available in a bundle might provide spares.
- MATERIAL SELECTION
5.1 Bundled tubing for instrument service shall be fabricated of metal tubes enclosed in a black polyethylene jacket.
5.2 Stainless steel tubing bundles shall be of cabled construction. The tubing, fittings, and valves used to terminate the tubing shall conform to 4PS52001A for copper tubing, or 4PS52002A or 4PS52003A for stainless steel tubing.
5.3 Copper tubing bundles may be either cabled or parallel construction (parallel is preferred for cost reasons).
5.4 Each tube within a bundle shall be identified with numeric markings repeated at intervals not to exceed 150 mm (6 in).
5.5 Each tube bundle shall include an insulated communication wire.
5.6 Bundled tubing used in hazardous locations shall be provided with a flame-retardant jacket.
5.7 Armored tube construction shall only be considered for special applications, such as direct- burial installations. Tube bundles must be approved for direct-buried conditions.
5.8 Tube bundles shall be provided in continuous lengths for installation between indicated points.
5.9 Company’ preferred suppliers for bundled tubing are Dekoron or Parker.
- CONDUIT SYSTEMS
6.1 Conduit systems designed for enclosure of bundled tubing shall conform to the following:
6.1.1 Maximum fill shall be 30% by area.
6.1.2 Long-radius elbows or bends shall be used.
6.1.3 The total bends between pull points shall not exceed 315 degrees for copper bundles and
45 degrees for stainless steel bundles.
6.1.4 Double conduit seals with a vent between them shall be provided in conduits which pass from a hazardous to nonhazardous operating area.
- JUNCTION BOXES AND BULKHEAD BARS
7.1 Junction boxes for tube bundles shall be fiberglass NEMA 4X enclosures with quick-release latches. Enclosure size will be specified on the hookup details. Bulkhead bars will be fabricated carbon steel angle. Refer to the electronic document storage system TEMPLATE INST 0506 for bulkhead plate design information.
7.2 Weather-tight compression fittings shall be provided for the entry of tube bundles into junction boxes. Bundles shall enter the top or bottom of junction boxes.
7.3 Bulkhead fittings shall be provided for the termination of individual tubes and shall be installed on both sides of the junction boxes.
7.4 Nameplates
7.4.1 Nameplates bearing the destination instrument shall be provided for each bulkhead fitting.
7.4.2 Nameplates shall be laminated, black plastic with white core, 13 mm (1/2 in) high with
5 mm (3/16 in) high letters.
7.4.3 Nameplates shall be attached to the exterior of the box with stainless steel screws.
- CLEANING
8.1 When any tube within a bundle must be decontaminated for oxygen service, all tubes within the bundle shall be cleaned to the same specification.
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