Frequent reference has been made to the lubrication charts. They are published in the OPs for older ordnance equipment and on MRCs for all ordnance equipment. These charts are necessary to do your maintenance job properly. Copies of some charts maybe obtained for use as checkoff lists. A sample chart is reproduced in figure 12-6. On it, you can seethe use of target symbols (Nos. 1 and 2) and schedules for lubrication. Large

Figure 12-6.-A sample lubrication chart.

equipments have several charts or MRCs with numerous places indicated for oiling or greasing. It would be easy to forget some places or to use the wrong lubricant if you did not have the chart or MRC to guide you and to check off as you work.

Lubrication Symbols

On lubrication charts and MRCs, lubricants and hydraulic fluids are identified by symbols, each symbol signifying a specific oil or grease. Examples are shown in figure 12-6. The symbols are identified in OD 3000.

Alternates and Substitutes

If the lubricant prescribed in the OP or MRC for a piece of equipment is not available, you may find it necessary to use either a substitute or an alternate lubricant.

A substitute lubricant is one that will fill the need for a limited time but does not have all the essential properties of the prescribed lubricant. As soon as the prescribed lubricant becomes available, all of the substitute must be removed, and the equipment must be completely relubricated with the prescribed material.

An alternate lubricant is one whose characteristics closely resemble those of the prescribed lubricant so that its removal is not necessary when the prescribed material is available.

Alternates and substitutes for prescribed Lubricants (as well as for cleaning materials, hydraulic oils, and preservatives) are listed in OD 3000. If none of the alternate lubricants are available, you must choose a substitute. Keep in mind that the substitute should be as near as possible to the specified lubricant in lubricating and rust-preventive qualities, viscosity, and ability to withstand the temperature ranges of the equipment. In brief, when the prescribed lubricant is not available, use an alternate if you can, a substitute if you must.

STOWAGE OF LUBRICANTS

Lubricants and related materials may bestowed for long periods before use. Although they are relatively stable, they are not inert, and proper stowage methods are important.

Many factors contribute to the deterioration of materials in stowage. The nature of their constituents makes them more or less susceptible to chemical and physical changes. These changes are accelerated by elevated temperatures, humidity, exposure, and the

presence of certain catalysts. The principal physical changes are separation and contamination,

Oxidation is the most common chemical reaction in stowed materials. It occurs when the material is exposed to air, particularly moist air, and is accelerated by high temperatures and the presence of certain catalysts. Materials containing soluble additives may deteriorate by decomposition or precipitation of the additive. These and other chemical changes can produce such harmful substances as acids, gases, water, insoluble gum, and sludge. Animal and vegetable oils are generally more susceptible to chemical change than mineral oils.

Physical changes include separation of oils from the soap component in greases and separation of insoluble additives from the parent material in oils. These changes may not be as serious as chemical changes, since a thorough mixing may restore the material to a usable state.

Rain, melted snow, and water vapor in the atmosphere can contaminate materials that are exposed _{or improperly sealed.} Water vapor trapped in the container before sealing can condense when the ambient temperature drops.

Generally, containers used to package materials supplied under specification requirements are suitable for stowage purposes. The effects of overheating, insufficient ventilation, and proximity to dangerous materials must be considered when handling and stowing lubricants and related materials. Good housekeeping in handling and stowage areas should be stressed at all times.

Containers, when stowed, should be handled carefully to avoid breakage. If they are stacked, overloading of the lower ones should be avoided, as this may open seams and permit loss of material. To prevent accumulation of water in their upper ends, you should stow drums on their sides. Lubricants and related materials should be segregated from explosives and other dangerous materials.

Before containers are stowed, they should be inspected for corrosion, leakage, and complete closure of all plugs, caps, and covers. All corrosion should be removed and the affected areas repainted.

During stowage, containers should be inspected frequently for leakage and corrosion. If tests indicate that the contents of leaking containers are in satisfactory condition, the materials should be transferred immediately to serviceable containers. The leaky containers should be removed and destroyed.

Stowage areas should be inspected for adequate drainage, foundations, and properly placed under undamaged tarpaulins. Any deficiency found during inspection should be corrected immediately.

Vapors from oils, greases, solvents, and similar products are flammable. When the vapors are combined with air in certain concentrations, they may form explosive mixtures that can be ignited easily by a spark, an open flame, or a lighted cigarette. To prevent accumulation of flammable vapors, you must ventilate stowage areas properly. To safeguard against fire and explosion, you should display warning signs prominently. Keep oil-fire extinguishing equipment available, and keep interiors of stacks open to permit entry of fire-fighting equipment. Only spark-enclosed forklift trucks should be used.

Flammable materials, such as oils, greases, and solvents, packed in metal containers or overpacked in fiberboard or wood boxes, are best protected when stowed in prescribed areas. Your ship should have an authorized stowage area for lubricants and other flammable materials. You may find it tempting to stow your often used grease gun and oil can in or near the gun mount. This is a dangerous practice and should be avoided. A temperature range of 40F to 80F is the most desirable for stowage.

Vapors from lubricants and related materials may frequently have a toxic effect on the human system. Every precaution should be taken to prevent excessive concentrations of such vapors in the air.

The following safety precautions should be observed when you are working with materials that have toxic effects:

1. Provide sufficient mechanical ventilation to reduce the concentration of toxic fumes to a safe level. When possible, ventilation should include an exhaust for fumes as well as intake for fresh air.

2. When a safe level of ventilation is doubtful, workers in the compartment should wear an air line respirator provided with a pure air supply.

3. Personnel working in a compartment where fumes may be above a safe toxic level should always work in pairs so that one person remains outside the compartment as a safety watch at all times. The person outside should have a respirator in case it is necessary to enter the compartment to bring out someone who has been overcome by toxic fumes.

In addition to the use and stowage of lubricants, new regulations are in effect that prescribe how lubricants are to be disposed. This includes oil- and grease-soaked rags. Your ship will have an instruction that details the disposal of these materials. As a petty officer, you must see that the regulations are observed by your personnel.