Preservation of items in the stores, particularly the slow moving spares parts, is an important job, but often ignored in the industry. In order to have an effective preservation programme, factors such as economic aspects, period of idleness of a part, conditions of the part, as well as applicability of specific protective’s should be considered.
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In the extreme cases, if the value of preservatives to be applied on the part exceeds the cost of the part, it is preferable to not have the preservatives. It is desirable to have a separate manual or a portion of the stores manual, exclusively devoted to the preservatives. The preservatives applied for some typical parts are mentioned below:
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(a) Bearing should be greased and packed in greased-proof papers.
(b) Expensive & delicate instrument parts should be kept in their boxes with cotton box of dehydrates silicate gel.
(c) Rubber articles should be dusted with French chalk.
(d) Bush bearings should be soaked in warm oil for 24 hours, once in a year.
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(e) In these cases, the exterior painting is done by bitumen or other protective paints.
(f) Valves are kept open to avoid metal to metal contact.
(g) The electrodes should be kept in original containers, in cool dry place.
(h) Vertical stocking of grinding wheels with partitioning in between is necessary, so that the fcces do not come into contact with each other.
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(i) Castings with machined faces, particularly, threaded portion and holes should be completely protected with grease, plugged in wherever necessary.
(j) Carbon steel exchanges are protected by filling gas oil or clean fresh water.
(k) LT motors should be cocooned.
(l) Switch gear parts should be enclosed in plastic bags.
(m) Strip heaters/dry air must be used for protecting big size switch gears.
(n) Oil lubricated bearings should be cleaned and filled with suitable ensis oils, while grease lubricated bearings should be cleaned and regressed and closed properly.
(o) Steel wire ropes should properly be cleaned and protected with a double coat of ensis fluids,
(p) Copper and copper alloys must be protected against ingress of ammonia/ammonium salts, (q) Silver and lead parts to be cleaned and rinsed with fresh water.
(r) Corrosive chemical containers must be labelled and storage areas demarcated by signs. Incompatible chemicals like acetone and mixture of concentrated nitric acid with sulphuric acid must not be stored together. Fluorine must be isolated from other items. Copper must not be stored near acetylene.
(s) Acids must be kept away from paper, wood and other items that are likely to corrode,
(t) Cylinders holding gases like oxygen, hydrogen, acetylene, are kept padded with coir, covered in separate folders away from sources of heat. It is preferable to keep phosphorus in kerosene.
(u) Vegetable oils should be protected from air, light and moisture. Paints must be guarded against moisture and the drums should be periodically inverted to prevent settling.
(v) Wood is susceptible to attack by white ants and a coating with paint or coaltar must be used. Bamboo must be kept submerged in water,
(w) Food grains can either be stored in soils or bags and fumigants must be used to protect grains against pest- attacks.
(x) Batteries must not be stored under humid or damp conditions and electrodes must be warmed up, before use.
(y) Glass sheet should not be kept one over the other, but must be kept upright and protected from sunlight,
(z) Cloth and paper must be protected from moisture, water, rats, white ants, etc. Similarly, rubber goods must be protected against light, sun rays, heat, air, moisture, ozone, oil, dust and dirt.
The above list is only illustrative and not exhaustive, and hence it is essential to prepare an exclusive manual on stores Preservatives. It is obvious that materials are to be stored without depreciating their physical properties and so they will have to be guarded against the effects of dampness, dryness, heat, cold, temperature, variations, humidity, and attack by insects, dust, dirt and similar factors.
The protective measures may alter the properties and care must be taken to keep these alterations without limits, commensurate with savings in the cost. In this context, legal aspects such as customers, excise, insurance, sales tax and other formalities must be adhered to, in the context of preservation.