POWER PLANT:MAINTAINABILITY WORKS-

POWER PLANT

 MAINTAINABILITY WORKS 

      The general technical requirements for plant maintainability equipment. 

These specifications shall be complied with in every respect unless otherwise stated or agreed by the Company/Engineer.

   

 METHODOLOGY:

             -  The equipment design and the related layouts as well as all the maintenance facilities shall be such that the routine and preventive maintenance, together with the repairs and the overhauls, will be eased.

-  The Contractor shall propose a methodology for the approval of the Company/Engineer, covering all aspects of the plant maintainability. The Contractor shall work out the scheme, which shall start from the beginning of the construction works of the Plant.

-   In this regard, The contractor shall designate a special team, being considered as a permanent contact for the Company/Engineer staff so as to submit and adjust step-by-step features of the scheme.

-   In principle, the methodology of the study and the preparation should consist of a series of orderly steps systematically applied to identify the systems and subsystems of the Plant, broken down according to the logic tree principle.

     CODE NUMBERING SYSTEM:

-    One of the prerequisites for the implementation of an optimized maintenance scheme is to establish a suitable equipment code numbering system.

 This system (which shall also include a color-coding system) of the whole plant equipment shall be proposed by the Contractor immediately after the award of Contract.

 -  All documents issued by the Contractor, such as but not limited to the equipment inventory list, diagrams, drawings, etc., as well as for instructions manuals, shall refer to the equipment with both label and identification code number.

 -   All nameplates, identification marks, panel labels, etc. shall bear the aforementioned full equipment label in English & Arabic languages and identification code numbers.

 -   Code numbering system shall cover the maximum number of distinct equipment to be identified but the number of letters and digits to be used shall always be the same (for example 1 letter + 4 digits + 1 letter).

 -  Code number identification shall not only cover the equipment but also items such as piping, valves, tanks, instruments and controls, electrical cabling and wiring, panels etc.
 -  It shall also indicate the type of equipment and fluid category.

     SUBMISSION OF PRELIMINARY SCHEME;

 -   As a first step of the maintenance scheme implementation, the Contractor shall submit at least three (3) months prior to the start of commercial operation of the first gas turbo generator,

 

a preliminary set of recommendations, which shall include but not limited to the following:

a] All categories of the personnel for power plant with their job description, qualification and number required.

b]         Operation program for maximum availability, reliability, economical performance.

c]         Maintenance schedules and programs to match with and assist the above operation program.

This shall include manufacturer’s maintenance philosophy and recommended organization so as to ensure maximum availability of the plant, and procedure on pulling equipment out and restoration in service, supported by safe clearance procedure, work permit-cards, check-sheets, recording method, etc. to guarantee safe and long life of the equipment.

 - This shall include the full safety of personnel, easy system of operating and maintaining of the warehouse (existing), ordering, receiving, issuing, and keeping the updated face value of warehouse store, the procedure for planning and implementing the above aspects.
 -  All the above shall be integrated afterward in final instruction manuals or another relevant final technical document.

     PREDICTIVE MAINTENANCE;

 -   Predictive maintenance shall be based on the follow-up of performance of the equipment and maintaining suitable parameters.

 -   The monitoring, analysis and reporting of performances shall be made available in the DCS.

 -   Medium and long-term observation of data trend shall indicate any deterioration of performances and, then, warn the responsible staff in giving the predictive limit of safe operation.

 -   Predictive maintenance systems shall also be proposed to be applied to other fields or items of the units or of the plant (for example based on vibration analysis, lube-oil spectrometric analysis, etc.), and the reports and programs generated by COMMS.

a]  The stipulated frequency shall be explained and fully justified
b] The extent of the parts to be inspected or to be systematically replaced shall also be justified and detailed in such a way that a clear estimate of predictive cost can be worked out
c]  Evaluative features of these operations shall be expected, i.e. the Contractor is required to explain what should be the practical trend throughout the life of the unit
d] To ease the access to the equipment components, accessories, instruments, and piping
e]  To allow the operation of the handling systems and principally of the overhead traveling crane

 - The unit shall be fitted with borescope ports or similar facilities for inspection of both compressor and turbine blading.

 - The Contractor shall provide built-in facilities against fouling abatement and especially related to:

a]   Offload compressor and turbine water washing.
 -   Being understood it will be the Contractor’s responsibility to stipulate the suitable cleaning or washing technique facing the specific type of fouling encountered at the site with the indicated fuel.

- One of the major features of the system are linked to the maintenance work requirements of HRSGs as the safe internal access during operation of the gas turbine depends upon both:

a]  The actual tightness of the damper flap in by-pass position (0 % gas leak required)
b]  The effectiveness of the thermal insulation of the flap.

 - Suitable ports, manholes and removable hatches shall be provided at required locations for internal inspection and maintenance work.

 - The turbine enclosure doors should preferably be the hinged type with the provision of complete removal during major maintenance.

-       As far as possible, ventilating and air conditioning equipment shall be standardized.

 -      One special dust bucket/drum with bottom emptying facilities through movable flaps the mechanism shall be provided for each gas turbine. Special fixtures shall be provided to enable it to be lifted easily by forklift and emptied in a dust dump truck.

 for turbine auxiliaries compartments/generators, hoisting equipment (traveling beam type) of adequate capacity shall be provided to enable easy removal of all auxiliaries not accessible from the turbine hall crane.

Specific provisions shall be made and suitable equipment shall be provided so as to permit easy removal of the rotor of the generators for inspection and overhaul.