Equipment preservation (conservation) is the temporary protection of a machine or component against corrosion, moisture and contamination during the transport and storage period between the factory and installation. It is carried out with protective oils and coatings, blanking plugs, nitrogen blanketing, VCI packaging and desiccants. The manufacturer's preservation instructions set the method, its duration and the conditions for renewal.
What does preservation protect, and why?
After a pump, valve or heat exchanger leaves the factory, it may wait months, sometimes years, before installation. During this time, salty air on the sea voyage, condensation from temperature changes in the warehouse, and dust and concrete residue on site attack the equipment. Preservation aims to deliver the equipment to installation as clean and sound as on the day it was manufactured.
The surfaces protected vary by equipment: machined flange faces, shaft and bearing seats, weld bevels, internal pipe surfaces, sealing elements and electrical connections. Nuclear equipment adds another dimension: chlorides and other contaminants are not accepted on stainless steel surfaces. Foreign matter entering the internal volume also requires cleaning before installation and extends the schedule.
Which methods are used?
| Method | How is it applied? | Typical use |
|---|---|---|
| Protective oil and grease | Brushed or sprayed on as a thin film | Shafts, gears, machined carbon steel surfaces |
| Strippable coating | Applied as a liquid, forms a film when dry, peeled off by hand at installation | Flange faces, precision-machined areas |
| Blanking plugs and blind flanges | All openings are closed with plugs, caps or gasketed blind flanges | Pipe ends, nozzles, valves |
| Nitrogen blanketing | The internal volume is filled with dry nitrogen, kept at slight positive pressure and monitored with a pressure gauge | Closed volumes such as vessels, heat exchangers and steam generators |
| VCI and desiccant | Vapour-phase corrosion inhibitor packaging, barrier foil and desiccant are used together | Crated equipment, spare parts |
| Climate-controlled storage | Storage in an enclosed area with temperature and humidity control | Electronics, control panels, sensitive components |
How VCI and desiccants work together is explained in detail in the VCI packaging and desiccants entry. On long sea voyages, the risk of condensation is assessed separately; the joint IMO/ILO/UNECE CTU Code devotes a separate annex to this topic.
How are preservation duration and renewal managed?
Every preservation has a period of validity. This period is stated in the manufacturer's preservation instructions and often in the equipment passport. For equipment manufactured in Russia, protection options and periods are frequently specified with reference to the GOST 9.014 standard. If installation cannot take place before the period expires, re-preservation is applied:
- The packaging is opened, and the old protective layer is assessed visually and, if necessary, by measurement.
- If there is corrosion or contamination, it is cleaned by a method approved by the manufacturer.
- The protective agent is reapplied, the desiccant is replaced and the nitrogen pressure is topped up.
- The work done, the date and the person carrying it out are recorded; the new validity period is written on the label.
Periodic checks are also carried out during storage: the nitrogen pressure gauge is read, the colour of the humidity indicator card is monitored and the integrity of plugs and foil is inspected.
Who is responsible?
- Manufacturer: Selects and applies the method and ships the instructions with the equipment.
- Logistics company: Carries the equipment without disturbing the preservation. Torn foil, a dislodged plug or loss of pressure should be noticed at transhipment points and recorded with photographs.
- Buyer and site warehouse: Inspect on delivery, place the equipment in the correct storage class and carry out the periodic checks. Storage classes are explained in the nuclear site storage levels entry.
The relationship between preservation and nuclear quality requirements is discussed in the transport conditions for safety-class equipment entry.
Common mistakes
- Closing a crate opened for customs inspection without replacing the desiccant.
- Checking nitrogen pressure only on delivery and dropping the monitoring in the warehouse.
- Not removing the protective oil with the solvent recommended by the manufacturer before installation.
- Not entering the preservation period in the storage plan.
Indoor storage options for equipment that requires long waiting periods are assessed together with the storage and distribution plan.
Frequently Asked Questions
Is equipment with damaged preservation accepted on site?
What information do preservation instructions contain?
What should be done if pressure drops in nitrogen-blanketed equipment?
Sources
- IMO – IMO/ILO/UNECE Code of Practice for Packing of Cargo Transport Units (CTU Code)
- GOST 9.014 – Temporary corrosion protection of products, general requirements