19.1.1 Vessel shall be protected against corrosion during shipping and at fabrication yard and construction sites.
19.1.2 Prior to shipping, vessels are to be completely and thoroughly dried and cleaned from all loose scales, weld slags, dirt and debris to the satisfaction of the Saudi Aramco Inspector.
19.1.3 The Vessel Manufacturer is responsible for ensuring that the vessels and internals being shipped are adequately braced and shall provide temporary supports where appropriate to ensure adequate supporting of the vessel during shipment.
19.1.4 Vessels partially shop fabricated and/or liable to suffer distortion during transit and erection shall be suitably braced. All ends that will be open during shipment shall be covered to prevent ingress of dirt and other foreign matters. The Vessel Manufacturer shall advise the Saudi Aramco Engineer of the method of protection for review and approval.
19.1.5 Markings shall be done with water-insoluble materials that contain no harmful substances that would attack or harmfully affect the vessel at both ambient and design temperatures.
19.1.6 Marking materials shall be free of lead, sulfur, zinc, cadmium, mercury, chlorine, or any other halogens.
19.1.7 Export packaging marking and shipping shall be in accordance with the purchase order.
19.2 Internal Protection
19.2.1 Thoroughly dry the internal surface of the vessel. Remove all free water. Thoroughly purge vessel with dry air so that relative humidity inside vessel is less than 40% at the lowest ambient temperature likely to be experienced in shipping and storage.
19.2.2 The interior surfaces of vessels, including internals, shall be protected from corrosion by the use of a nontoxic liquid or powder vapor phase corrosion inhibitor (VpCI) that is compatible with the metallurgy of all components in the equipment being protected and is environmentally friendly for disposal at sea. The chemistry shall be based on amine carboxylates, amine benzoates, or amine oleates with additional components as necessary. Nitrites shall not be used.
Following are specific requirements for corrosion inhibitors:
19.2.2.1 Water-soluble liquid products shall provide both vapor phase and contact inhibition. These products shall be applied at the rate of 1 liter per cubic meter of internal space or the
minimum specified by the inhibitor manufacturer, whichever is greater. Liquid products are preferred as these are easily removed with the process flow on start up.
19.2.2.2 Ready to spray, oil soluble liquid vapor phase corrosion inhibitors can be used at a surface application rate of 25 to 30 square meters per liter of chemical, or the minimum
application rate recommended by vendor, whichever is greater.
Oil soluble inhibitors will leave an oily film on the interior of the equipment that must be acceptable to the end user.
19.2.2.3 Powders shall be free flowing crystals for ease of application and be environmentally friendly for disposal at sea if
necessary. Powder products shall be applied at the rate of 0.3 kg per cubic meter of internal void space or the
minimum specified by the inhibitor manufacturer, whichever is greater. Powder can be fogged into the equipment or it can be placed inside Tyvek bags and then placed inside the equipment. Tyvek bags must be removed before start-up.
For gas and LNG service, excess loose powder must be removed before start-up by vacuuming or by water rinsing.
19.2.2.4 Products shall be tested per NACE TM0208-2008 and shall provide Grade 3 or Grade 4 performance. When the equipment contains a copper/copper alloy component, the VpCI shall also be tested per Section 7 of NACE TM0208-2008.
19.2.2.5 For any questions on application rates, or any situations requiring clarification or for approval of other products, forms, or chemistries of vapor phase corrosion inhibitors, obtain the prior written approval of the Supervisor, Corrosion Technology Unit, Materials Engineering and Corrosion Control Division, CSD.
19.2.2.6 Vessels must be sealed vapor tight using metallic covers, for inhibitors to be effective.
19.2.3 For vessels made completely of stainless steels and vessels internally cladded or weld-overlaid with these materials, in addition vapor phase corrosion inhibitors applied per 19.2.2, nitrogen blanketing shall be used during shipment or periods of storage at the construction site.
To apply nitrogen blanketing, pressurize the vessel to 60 psig with nitrogen and bleed down slowly to 5 psig. Pressurization in this manner shall be repeated 3 times. Bleed down must be slow and controlled to minimize the loss of vapor phase inhibitor. The vessel shall be clearly marked with a warning:
“Warning: asphyxiation hazard--preserved with nitrogen.”
19.2.4 For vessels that have permanent internal coatings covering some or all of the vessel internals, the Vessel Manufacturer shall contact the Supervisor, Corrosion Technology Unit, Materials Engineering and Corrosion Control Division, CSD, and obtain prior written agreement on required preservation techniques.
19.2.5 Use of non-toxic desiccants is considered acceptable as an alternative internal protection measure against corrosion for vessels ONLY when the warranty will be revoked by using non-toxic vapor phase inhibitor;
provided that the following conditions are met:
19.2.5.1 The plan is pre-approved in writing by the Supervisor, Corrosion Technology Unit, Materials Engineering and Corrosion Control Division, CSD.
19.2.5.2 Silica gel application rate shall be a minimum of 3.0 kg per cubic meter of internal space.
19.2.5.3 The vessel shall be maintained 100% vapor tight using bolted metal blind flanges.
19.2.5.4 The plan includes methods and designated responsible persons to evaluate the condition of the desiccant and re-apply if necessary.
19.2.5.5 Calcium chloride desiccants shall not be used.
19.2.5.6 The desiccant must be removed on site prior to operating the vessel.
Commentary Note:
These circumstances have arisen in the past when a vessel is shipped from a manufacturer with a catalyst in place prior to field erection.
19.2.6 Other preservation products or methods may be applied with the prior written approval of the Supervisor, Corrosion Technology Unit, Materials Engineering and Corrosion Control Division, CSD.
19.3 External Protection
19.3.1 The protection of external surfaces shall be obtained by using one of the following:
a) A hard temporary preservative appropriate for the metallurgy of the vessel and can be easily removed at site prior to surface preparation and application of the Saudi Aramco coating and painting system.
b) Prepare the surface and apply the complete (primer and final coatings) Saudi Aramco surface preparation, and coating and painting system in the shop.
c) For solid Stainless Steel vessels, which are to be shipped via ocean freight, shall be protected using a temporary protective system compatible with stainless steel and suitable outdoor exposure.
19.3.2 Telltale holes in reinforcing pads shall be protected with wooden plugs or packed with rust preventative grease.
19.3.3 Flanged connections and all other machined surfaces shall be protected by a coating suitable for the metallurgy of the vessel and can be easily removed in the field. Connections shall be fitted with steel or wood cover, 3 mm thick and neoprene gaskets.
19.3.4 Covers shall be securely attached by a minimum of four bolts equally spaced. For ocean shipment, flanged connections shall also be covered with heavy-duty plastic bags securely taped to the nozzles.
19.3.5 Flanges with permanent blind flanges or covers shall be secured with the gaskets and bolting specified for service.