Development of designs for higher life, improved energy efficiency, less maintenance and user-friendly operation and handling is the most important desirable engineering function. As soon is product comes out of the factory duly tested and installed at the purchaser’s premises, the responsibility for its long life, as stated by the manufacture in its product guidelines, starts at the hand of the user. How to specify the product for this important need? I have compiled some of the points which are generally missing in the specification and also during testing because it is not part of the type/routine test.
Maintenance of Equipment
Maintenance is an important function performed by the asset holding organization during the entire life of the product involving maintenance cost, operating cost and replacement cost if replaced prematurely. Maintenance cost involves two components 1. Checking, cleaning, oiling, etc. This involves very little cost and natural to the service performed. But one shall not forget that the technology has advanced so much that even oil free compressor are available requiring almost no maintenance. Automobiles are also moving towards such design practices. Therefore, such need shall be deliberated. 2. Replacement of limited life items, depending on natural wear and aging. Seeking information for such items is generally not specified. In order to achieve satisfactory service during its entire service life span, it is important that the firm shall specify the life of the wearing and aging parts with test data. The purchasers shall study the specification of these items and may like to contribute with technical input to improve the life of these components. Involvement of purchaser at this stage also helps in standardization of spares so that inventory of such items for different makes does not differ.
Ingress of dust and moisture is one of the major reason of many of the unscheduled failures or even adding maintenance cost. Purchaser defines the Protection degree (IP Class) in the specification depending on the service and installation environment of the product. IP type test results are checked, but how long the degree of protection will last is neither asked from the vender nor validation check done at intervals. It is a fact that the IP life is dependent on the quality and designs of sealants used and certainly have limited life. It is stated at many of the times that the IP status got disturbed at the time of installation itself unknowingly.
In view of the above, the purchaser specification shall always ask the design features used to achieve IP status and a test scheme to validate the same in service at interval not all but at least part test. The purchaser shall also ask the life of IP and rehabilitation frequency. Although this is not covered by any International Standard yet the right of the purchaser is always supreme. It is a general tendency, that the manufacture remains silent on these items and become wise after the material is delivered.
Fire safety is very important for the design of any installation or equipment. Prevention of both the fire initiation and propagation shall have inbuilt design feature. All vendors shall be asked not to use any product in the assembly which are nonfire retardant and produces smoke and toxic gases. This includes even paint, rubber gaskets etc. If it is not possible to develop such designs or having cost implication, then a list of such components shall be submitted with inbuilt preventive mechanism to contain the effect, if any. The manufacturers sometimes, are so careless that they don’t even bother the material that goes in the manufacturing of an item. Indian Railways had a dreadful time of fire incidences on Power Cars equipped with a particular make of DG sets. This manufacture has used the exhaust manifold of material which was highly combustible and when ignited burns like a crude product. A video can make one alert about the relevance of this clause. There are many instances of fire originating at AC and propagating due to use of fire non- retardant material and led to complete gutting of all the equipment in the room.
Electrical Protection is generally a design feature in any product. Sometime it is specified, but otherwise it is the responsibility of the manufacturer to ensure it in the design. It is necessary for the purchaser to understand the protection scheme incorporated in the design. The robust protection scheme helps in arresting consequential damages. There shall be a provision in the design scheme wherein there is no scope for anyone to interfere with the protection scheme and its setting. With numerical controls, the protection scheme has advanced considerably and one should look for the solution towards all types of fault.
There are two aspects involved in a design of a product. One is internal and another interface with the user. The internal design is the prerogative of the designer and it may not be possible for the purchase to involve and contribute. But standardisation of aspects which are to be touched/handled/read/hear by the user is important. Lists of such items are
- Lettering size and color of the instructions relevant and important for the operating staff
- Minimum size of display unit
- Size and height of the operating handle, knobs, marking thereon, and direction of its movement.
- Trouble Shooting
Handing over of Documentation
The asset on commissioning is being handed over to Operation and Maintenance organisation. Documentation of the asset is very important for the O&M. The manufacturer shall submit bound booklet to the authorised O&M staff with signature consisting of the following documents
- Name of the authorised person of the vendor entrusted with the responsibility of attending breakdown up to warranty period.
- Functional description of the equipment
- Operating Manual shows all the commands which are in the control of operating staff
- Maintenance manual duly approved by Purchaser. It is important that the manufacture shall include only those items in the maintenance manual which are agreed upon by the purchaser.
- List of maintenance spares supplied with the equipment as per the contract
- List of staff trained in the operation and maintenance on the equipment
- Training manual given to the maintenance staff along with the soft copy CD
- Extracts from the contract with warranty clause, special conditions/AMC etc.
Type test is defined as the tests conducted on the product to validate the design. The test result when found within the specified values assures the purchaser about the design, manufacturing process and quality of raw material used in the product. Design and manufacturing process normally does not change, but the specification and vendor of material may undergo a change. Therefore, it is necessary to specify that the firm shall submit the bill of material along with the type test result and shall ensure continuity during regular supply. Any subsequent change in the vendor or specification of raw material shall be with the consent of the purchaser.
All products procured by Indian Railways related to train operation are procured as per RDSO specification and RDSO approved sources. These products are manufactured for specific application of Railways and generally at a higher cost as compared to the costs of the equivalent product available of the shelf in the market. It is very convenient for RDSO to include these clauses in the specification for sustainability of the product through out its life.