ATCH_ASHE20-1068A_Maintenance_Annex.pdf

31st FIGHTER WING 31st CIVIL ENGINEERING SQUADRON

31st CES/CENM PROJECT MANAGEMENT ELEMENT

PROJECT ASHE 20-1068A

REPAIR MV FLIGHTLINE LOOP (DSN), AVIANO AB, ITALY

ELECTRICAL SYSTEM WORKS ANNEX

ORDINARY MAINTENANCE SCHEDULES

Project ASHE 20-1068A July 2023

31 CES/CENM

REPAIR MV FLIGHTLINE LOOP (DSN) ASHE20-1068A

ELECTRICAL SYSTEM ORDINARY MAINTENACE ANNEX Page 2 of 4

THIS PAGE LEFT INTENTIONALLY BLANK

ASHE20-1068

FINAL (100% design) ELECTRICAL SYSTEM ORDINARY MAINTENACE ANNEX Page 3 of 4

PREFACE

Electrical systems need regular maintenance to ensure continued compliance with the codes. The instructions included in the next pages provide guidance for operations and maintenance of electrical power and distribution systems existing in the Aviano A.B. substations.

The guidance and standards contained within are the minimum requirements acceptable. The provided guidance does not automatically supersede equipment manufacturers’ instructions and requirements. When conflicts exist, the most rigorous requirement must be followed.

SAFETY

All the electrical workers must be thoroughly trained and be familiar with the equipment and procedures to be followed. Properly trained electric workers will be certified in accordance with applicable publications.

Maintenance must be performed in compliance with the requirements of:

- Occupational Safety and Health (OSHA)

- D.Lgs 81/08

REPAIR MV FLIGHTLINE LOOP (DSN)

SUBSTATION - General Table 0

Preventive maintenance activities Minimal Frequency, Performance Level (years)

Y1 Y2 Y3 Y4 Y5 Y6 Y7 Y8 Y9 Y1

Walls, pavement, roof, cable trenches, doors, ventilation grilles Interior and exterior walls condition n n n n n Roof condition n n Cleaning pavement and cable trenches n n n n n n n n n n Interior space temperature and humidity instrumental cheking, performed in the summer season (in the hottest weeks) n n n n n n n n n n

Ordinary lighting system Inspection lighting functionality n n n n n n n n n n Emergency lighting system Inspection emergency lighting functionality n n n n n n n n n n Power receptacles Inspection of power receptacles functionality n n Notification devices Inspection of visual and acoustical notification devices funciontality n n n n n n n n n n One-line diagrams Visual inspection of the update of the one-line diagrams n n n n n n n n n n

Visual inspection of the update labels on switchboard and panelboard circuits. Adjustment where needed n n n n n n n n n n

Grounding test Residual current device (RCD) instrumental test n n n n n n n n n n Bonding and grounding connections continuity test n n n n n Grounding resistance test n n n n n

MV switchboard - FUSE cubicle, CONTACTOR cubicle recommended maintenance activities

Table 1

Preventive maintenance activities Minimal Frequency, Performance Level (years)

Y1 Y2 Y3 Y4 Y5 Y6 Y7 Y8 Y9 Y1

LV Compartment Checking of connections n n n n n n n n n n Checking of wirings n n n n n n n n n n Cubicle Cleaning cubicle / internal equipment n n n n n n n n n n Inspection of the position indicators and signalling micro switches n n n n n n n n n n Inspection of locking + interlocking mechanism function n n n n n Inspection of the shutters n n n n n Cleaning / checking switch line operating mechanism n n Cleaning / checking of isolators (tightening , chalking, cracking, signs of heating) n n Cleaning / checking of earthing switch operating mechanism n n Cleaning / checking / greasing of earthing switch plugs n n Cleaning / checking / greasing of shutter locking system n n Cables compartment Inspection of cables (tightening ,chalking, cracking, signs of heating) n n n n n n n n n n Inspection of isolators (tightening ,chalking, cracking, signs of heating) n n n n n n n n n n CT / VT compartment Cleaning / inspection of isolators (tightening, chalking, cracking, signs of heating) n n Cleaning / inspection of TPs (tightening, chalking, cracking, signs of heating) n n Busbar compartment (power off) Inspection of busbars (cleaning, tightening, chalking, cracking, signs of heating) n n Inspection of isolators (cleaning, tightening, chalking, cracking, signs of heating) n n Contactor Inspection of enclosure (chalking, cracking, signs of heating) n n n n n n n n n n Inspection of connections (tightening, chalking, signs of heating) n n n n n n n n n n Inspection / check of auxiliairies contacts (signaling contacts, coils, wiring) n n n n n n n n n n Inspection / checking / adjustment of latching system n n Inspection / adjustment of coil contact insertion n n Checking wearing and simultaneity of arcing contacts n n Cleaning / checking / greasing of all linkages n n Check LV electrical wiring connections n n Tests Mechanical (manual on/off) n n n n n n n n n n Electrical (remote on/off) n n n n n n n n n n Fuses Inspection of fuse (chalking, color, cracking, corrosion) n n n n n n n n n n Inspection of fuse fixing n n n n n n n n n n Inspection of fuse signaling microswitch n n n n n n n n n n Inspection of fuse signaling striker n n n n n n n n n n Associated protection Inspection of protection relay (setting , tripping functions) n n Inspection of upstream / downstream selectivity n n Spare Parts Parts commonly used in corrective maintenance interventions Relay, LV Fuse Auxilliary Contact Tripping coil

MV switchboard - Circuit Breaker, Switch cubicle

Table 2

Preventive maintenance activities Minimal Frequency(1) / Performance Level

Y1 Y2 Y3 Y4 Y5 Y6 Y7 Y8 Y9 Y1

LV Compartment Inspection of auxiliairies equipmemts n n n n n n n n n n Inspection of wiring connections (tightening, fixing) n n n n n n n n n n Cubicle Cleaning cubicle / internal equipment n n n n n n n n n n Inspection of the position indicators and signalling micro switches n n n n n n n n n n Inspection of locking + interlocking mechanism function n n n n n Inspection of withdrawal mechanism n n n n n Inspection of the shutters n n Cleaning / checking switch line operating mechanism n n Cleaning / checking of isolators (tightening ,chalking,cracking , signs of heating) n n Cleaning / checking of earthing switch operating mechanism n n Cleaning / checking / greasing of earthing switch plugs n n Cables compartment Inspection of cables (cracking, signs of heating) n n n n n n n n n n Inspection of wiring connections (tightening, fixing) n n n n n n n n n n CT / VT compartment Cleaning / inspection of isolators (tightening, chalking, cracking, signs of heating) n n Cleaning / inspection of TPs (tightening, chalking, cracking, signs of heating) n n Busbar compartment Inspection of busbars (cleaning, tightening ,chalking,cracking, signs of heating) n n Inspection of isolator switches (cleaning, tightening ,chalking,cracking, signs of heating) n n

Circuit breaker General state: visual checking, cleanliness, insulator condition, oxidation,no corrosion of supporting structure n n n n n n n n n n

Checking of number of operation n n n n n n n n n n Cleaning of resin bodies n n n n n n n n n n Inspection of state of the auxiliairies contact (on/off , rack in ,rack off etc.) n n n n n n n n n n Inspection of functionnal and safety interlock on device n n n n n n n n n n Cleaning / checking / greasing of the power contacts (plugs , sliding contact , light greasing) n n

Measurement of main contact resistance (microhmeter) n n Cleaning /checking / greasing of the moving withdrawable parts n n Checking of coupling rods n n Cleaning / checking / greasing of the operating mechanism n n Cleaning / checking / greasing of the latching mechanism n n Cleaning / checking / greasing of the closing and opening springs n n Cleaning / checking / greasing of the motor and reduce n n Cleaning / checking / greasing of all linkages n n Check LV electrical wiring connections n n Tests Mechanical (manual on/off) n n n n n n n n n n Electrical (remote on/off) n n n n n n n n n n Associated protection Inspection of protection relay (setting , tripping functions) n n Inspection of upstream / downstream selectivity n n Manufacturer's authorized maintenance service Diagnosis

Breaker Monitors opening / closing / spring-loading operations drifts n n Checking / adjusting of condition ot the damper and / or stop device n n Checking of opening / closing times and speeds n n Checking of charging time n n Checking of contact synchronization n n Checking of safety to close (overtravel and stabilisation) n n Checking of safety to open (overtravel and stabilisation) n n Spare Parts Secure: Parts commonly used in corrective maintenance interventions Relay, LV Fuse Auxilliary Contact Tripping coil

Diagnosis to detect drifts from the initial state and significant trends, to anticipate on the corrective action (future failures) required to ensure equipment safety and continuity of service, and plan the action for the most convenient time for customer operations.

MV switchboard - Switch cubicle

Table 3

Preventive maintenance activities Minimal Frequency(1) / Performance Level

Y1 Y2 Y3 Y4 Y5 Y6 Y7 Y8 Y9 Y1

LV Compartment Checking of connexions n n n n n n n n n n Checking of wiring n n n n n n n n n n Cables compartment Inspection of cables (cracking, signs of heating) n n n n n n n n n n Inspection of wiring connections (tightening, fixing) n n n n n n n n n n Cleaning / checking / greasing of the earthing switch connection contacts n n Equipment compartment Cleaning / checking of active part and enclosure (chalking, cracking, signs of heating) n n n n n n n n n n Cleaning / checking of isolators (chalking, signs of heating) n n n n n n n n n n Checking of lock and inter-lock system n n n n n n n n n n Checking of auxiliairies contacts position indicator n n n n n n n n n n Cleaning / Checking of operating mechanism n n Cleaning / checking of the earthing switch operating mechanism n n Busbar compartment (power off) Inspection of busbars (signs of heating) n n n n n n n n n n Inspection of isolator switches (chalking, signs of heating) n n n n n n n n n n CT / VT (optional) Cleaning / inspection of isolators (tightening ,chalking,cracking , signs of heating) Cleaning / inspection of TPs (tightening ,chalking,cracking , signs of heating) n n Tests Mechanical (manual on/off) n n n n n n n n n n Electrical (remote on/off) n n n n n n n n n n Spare Parts Secure: Parts commonly used in corrective maintenance interventions Relay, LV Fuse Auxilliary Contact Tripping coil

MV switchboard - FUSE SWITCH cubicle

Table 4

Preventive maintenance activities Minimal Frequency(1) / Performance Level

Y1 Y2 Y3 Y4 Y5 Y6 Y7 Y8 Y9 Y1

LV Compartment Inspection of connections n n n n n n n n n n Inspection of wiring n n n n n n n n n n Cables compartment Inspection of cables (cracking, signs of heating) n n n n n n n n n n Inspection of wiring connections (tightening, fixing) n n n n n n n n n n Cleaning / checking / greasing of the earthing switch connection contacts n n Equipment compartment Cleaning / checking of active part and enclosure (chalking, cracking, signs of heating) n n n n n n n n n n Cleaning / checking of isolators (chalking, signs of heating) n n n n n n n n n n Checking of lock and inter-lock system n n n n n n n n n n Checking of auxiliairies contacts position indicator n n n n n n n n n n Cleaning / Checking of operating mechanism n n Cleaning / checking of the earthing switch operating mechanism n n Fuses Inspection of fuse (chalking, color, cracking, corrosion) n n n n n n n n n n Inspection of fuse fixing n n n n n n n n n n Inspection of fuse signaling microswitch n n n n n n n n n n Inspection of fuse striker n n n n n n n n n n Busbar compartment (power off) Inspection of busbars (signs of heating) n n Inspection of isolator switches (chalking, signs of heating) n n

CT / VT

Cleaning / inspection of isolators (tightening ,chalking,cracking , signs of heating) n n Cleaning / inspection of TPs (tightening ,chalking,cracking , signs of heating) n n Tests Mechanical (manual on/off) n n n n n n n n n n Electrical (remote on/off) n n n n n n n n n n Manufacturer's authorized maintenance service Diagnosis

Surface/internal partial discharges detection n n

Mesurement of fuses internal impedance / comparison with manufacturer's data n n

Spare Parts Secure: Parts commonly used in corrective maintenance interventions Relay, LV Fuse Auxilliary Contact Tripping coil

Diagnosis to detect drifts from the initial state and significant trends, to anticipate on the corrective action (future failures) required to ensure equipment safety and continuity of service, and plan the action for the most convenient time for customer operations.

MV switchboard - METERING cubicle

Table 5

Preventive maintenance activities Minimal Frequency(1) / Performance Level

Y1 Y2 Y3 Y4 Y5 Y6 Y7 Y8 Y9 Y1

LV Compartment Inspection of connections n n n n n n n n n n Inspection of wiring n n n n n n n n n n Equipment compartment Cleaning / checking of active part and enclosure (chalking, cracking, signs of heating) n n n n n n n n n n Cleaning / checking of isolators (chalking, signs of heating) n n n n n n n n n n Checking of lock and inter-lock system n n n n n n n n n n Checking of auxiliairies contacts position indicator n n n n n n n n n n Cleaning / Checking of operating mechanism n n Cleaning / checking of the earthing switch operating mechanism n n Fuses Inspection of fuse (chalking, color, cracking, corrosion) n n n n n n n n n n Inspection of fuse fixing n n n n n n n n n n Inspection of fuse signaling microswitch n n n n n n n n n n Inspection of fuse striker n n n n n n n n n n Busbar compartment (power off) Inspection of busbars (signs of heating) n n Inspection of isolator switches (chalking, signs of heating) n n

CT / VT

Cleaning / inspection of isolators (tightening ,chalking,cracking , signs of heating) n n Cleaning / inspection of TPs (tightening ,chalking,cracking , signs of heating) n n Tests Mechanical (manual on/off) n n n n n n n n n n Electrical (remote on/off) n n n n n n n n n n Manufacturer's authorized maintenance service Diagnosis

Surface/internal partial discharges detection. n n

Mesurement of fuses internal impedance / comparison with manufacturer's data n n

Spare Parts Secure: Parts commonly used in corrective maintenance interventions Auxilliary Contact

Diagnosis to detect drifts from the initial state and significant trends, to anticipate on the corrective action (future failures) required to ensure equipment safety and continuity of service, and plan the action for the most convenient time for customer operations.

MV switchboard - RING MAIN unit

Table 6

Preventive maintenance activities Minimal Frequency(1) / Performance Level

Y1 Y2 Y3 Y4 Y5 Y6 Y7 Y8 Y9 Y1

Equipment compartment Cleaning / checking of active part and enclosure (chalking, cracking, signs of heating) n n n n n n n n n n Checking of lock and inter-lock system n n n n n n n n n n Checking of auxiliairies contacts position indicator n n n n n n n n n n Cleaning / Checking of operating mechanism n n Cleaning / checking of the earthing switch operating mechanism n n Cables compartment Inspection of cables (chalking, signs of heating) n n n n n n n n n n Inspection of cable connections (tightening, fixing) n n n n n n n n n n Fuses compartment Inspection (visual) of the fuse (chalking, color, cracking, corrosion) n n n n n n n n n n Cleaning of fuse n n n n n n n n n n Checking of fuse signaling indicator n n n n n n n n n n Inspection of fuse fixing n n n n n n n n n n Cleaning / checking fuse contact plugs n n Tests

Mechanical (manual on/off) n n n n n n n n n n

Electrical (remote on/off) n n n n n n n n n n

Associated protection Inspection of protection relay (setting , tripping functions) n n Manufacturer's authorized maintenance service Diagnosis offers

Surface/internal partial discharges detection. n n Mesurement of fuses internal impedance / comparison with manufacturer's data n n Spare Parts Secure: Parts commonly used in corrective maintenance interventions Relay, LV Fuse Light maintenance Auxilliary Contact Light maintenance Tripping coil Light maintenance

Diagnosis to detect drifts from the initial state and significant trends, to anticipate on the corrective action (future failures) required to ensure equipment safety and continuity of service, and plan the action for the most convenient time for customer

PROTECTION RELAYS

Table 7

Preventive maintenance activities Minimal Frequency(1) / Performance Level

Y1 Y2 Y3 Y4 Y5 Y6 Y7 Y8 Y9 Y1

Inspection of protection measured values, alarms, battery status through HMI n n n n n n n n n n Inspection of connexions n n n n n n n n n n Inspection of wiring n n n n n n n n n n Inspection of tripping circuits n n n n n Checking of tripping curves n n Inspection of protection measured values, alarms, battery status through HMI n n Downstream / upstream blocking or permissive scheme n n

Manufacturer's authorized maintenance service Diagnosis Monitors MV relay protection function and their performance according to predefined settings . n n

Inspection of tripping circuits n n Checking of tripping curves n n Inspection of protection settings n n Spare Parts Secure: Parts commonly used in corrective maintenance interventions RS485 interface / Communication module Input / Output module Sensor module Battery

POWER TRANSFORMERS

Table 8

Preventive maintenance activities Minimal Frequency(1) / Performance Level

O il Y1 Y2 Y3 Y4 Y5 Y6 Y7 Y8 Y9 Y1

Visual inspection Inspection of connections (heating, discharges, etc.) n n n n n Inspection of magnetic circuit appearance n n n n n Inspection of degradation of surface coating and transformer components n n n n n Inspection of Oil level (except for integral-filling devices) n n n n n Inspection of visual leakages (Crack for CRT) n n n n n Checking of environmental issues (pollution / fires) n n n n n Checking of winding n n n n n Cleaning Dedusting n n n n n n n n n n Cleaning of transformer compartment n n n n n n n n n n

Verifications / repairs Checking of transformer's protection systems n n n n n Checking of air dryer and repair if needed n n n n n Checking of accessories (temperature probe, …) n n n n n Leakage repair n n n n n Tests Noise test n n LV electrical testing n n MV electrical testing (coupling, isolation resistance, …) n n

Upgrading / Regulation compliance IP housing for electrical safety n n n n n n n n n n Spare Parts Secure: Parts commonly used in corrective maintenance interventions Auxiliary equipments (temperature probe, …)

Ca st

R es in

DISTRIBUTION TRANSFORMERS

Table 8

Preventive maintenance activities Minimal Frequency(1) / Performance Level

O il Y1 Y2 Y3 Y4 Y5 Y6 Y7 Y8 Y9 Y1

Visual inspection Inspection of connections (heating, discharges, etc.) n n n n n Inspection of magnetic circuit appearance n n n n n Inspection of degradation of surface coating and transformer components n n n n n Inspection of Oil level (except for integral-filling devices) n n n n n Inspection of visual leakages (Crack for CRT) n n n n n Checking of environmental issues (pollution / fires) n n n n n Checking of winding n n n n n Cleaning Dedusting n n n n n n n n n n Cleaning of transformer compartment n n n n n n n n n n

Verifications / repairs Checking of transformer's protection systems n n n n n Checking of air dryer and repair if needed n n n n n Checking of accessories (temperature probe, …) n n n n n Leakage repair n n n n n Tests Noise test n n LV electrical testing n n MV electrical testing (coupling, isolation resistance, …) n n

Upgrading / Regulation compliance IP housing for electrical safety n n n n n n n n n n Spare Parts Secure: Parts commonly used in corrective maintenance interventions Auxiliary equipments (temperature probe, …)

Ca st

R es in

POWER TRANSFORMERS

Table 9

Preventive maintenance activities Minimal Frequency(1) / Performance Level

Y1 Y2 Y3 Y4 Y5 Y6 Y7 Y8 Y9 Y1

Visual inspection Inspection of connections (heating, discharges, etc.) n n n n n Inspection of visual leakages (Crack for CRT) n n n n n Inspection of Oil level (except for integral-filling devices) n n n n n Checking of environmental issues (pollution / fires) n n n n n Cleaning Dedusting n n n n n n n n n n Cleaning of transformer compartment n n n n n n n n n n Cleaning of Fans and motor fans testing n n n n n n n n n n Cleaning of bushing (and winding for CRT) n n n n n n n n n n

Verifications / repairs Checking of auxiliary equipments n n n n n Checking of transformer's protection systems n n n n n Checking of air dryer and repair if needed n n n n n Checking of accessories (temperature probe, indicators, ...) n n n n n Leakage repair n n n n n Tests LV electrical testing n n Noise test n n MV electrical n n

Upgrading / Regulation compliance IP housing for electrical safety n n n n n n n n n n Spare Parts Secure: Parts commonly used in corrective maintenance interventions Auxiliary equipments (temperature probe, …)

LOW VOLTAGE - Switch Disconnector

Table 10

Preventive maintenance activities Minimal Frequency(1) / Performance Level

Y1 Y2 Y3 Y4 Y5 Y6 Y7 Y8 Y9 Y1

Circuit breaker Dismantle / check of breaking chambers n n Cleaning / greasing of operating mechanism n n Checking on the wear on contacts / arc chutes n n Inspection of auxiliary contacts (O/C, SDE) n n n n n Chassis (withdrawable) Inspection / cleaning of chassis n n n n n Clean / grease of racking screw n n Inspection of safety devices (tripping on withdrawal, interlocks) n n n n n Device connection tests n n n n n Tests Mechanical (manual on/off) n n n n n Electrical (remote on/off) n n n n n Manufacturer's authorized maintenance service Diagnosis Checking / adjusting of condition ot the damper and / or stop device n n Checking of opening / closing times and speeds n n Checking of charging time n n Checking of contact synchronization n n Checking of safety to close (overtravel and stabilisation) n n Checking of safety to open (overtravel and stabilisation) n n Monitors circuit-breakers control unit tripping performance n n Identifies hot spots suffering from overheating due to bad connections, harmonics, overloads n n

Recommended Spare Parts Secure: Parts commonly used in corrective maintenance interventions Auxiliary contacts Closing / opening coil Undervoltage coil

LOW VOLTAGE SWITCHBOARD

Table 11

Preventive maintenance activities Minimal Frequency(1) / Performance Level

Y1 Y2 Y3 Y4 Y5 Y6 Y7 Y8 Y9 Y1

Electrical room Inspection of support levelness (alignment) n n Fixed part n n Chassis (withdrawable) Efficiency / presence of interlocking devices n n n n n Cover panel / partition: doors, form covers, automatic shutters, screws, keys n n n n n Inspection of general appearance: cleanliness, presence of humidity/oxidation n n n n n Inspection of strain n n n n n Dedusting of switchboard n n n n n Indications Inspection of indicators (indicator lights, mechanical indicators, etc.) n n n n n n n n n n Checking signalling / measuring equipment values n n Connections Inspection of heating n n n n n n n n n n Inspection of power connections: busbars, terminations, busbar supports. n n n n n n n n n n Inspection of downstream connections: connecting pads, cable mechanical strenght n n n n n Inspection of earth connections. continuity of the grounds n n n n n n n n n n Inspection of clamp connections: wear / greasing n n n n n n n n n n Inspection of cable connections (tightening, fixing) n n n n n n n n n n Inspection of auxiliary connections n n n n n n n n n n Checking of shutter moves freely n n n n n n n n n n Checking of drawer locks operates correctly n n n n n Cleaning / greasing of slides n n n n n n n n n n Checking of condition of collector n n n n n n n n n n Checking of isolation n n n n n n n n n n LV plug-in drawers n n n n n n n n n n Inspection / cleaning of the drawer n n n n n n n n n n Inspection of safety devices (tripping on withdrawal, interlocks) n n n n n n n n n n Switchgear / controlgear Dedusting n n n n n n n n n n Inspection of opening / closing n n n n n n n n n n Inspection of switchgear wearing parts: main contacts, arcing chamber. n n n n n Other diagnosis: thermography Identifies hot spots suffering from overheating due to bad connections, harmonics, overloads n n n n n

Spare Parts Secure: Parts commonly used in corrective maintenance interventions Tripping microswitch unit Limit switch Mechanical reset relay

LOW VOLTAGE POWER FACTOR CORRECTION UNITS

Table 12

Preventive maintenance activities Minimal Frequency(1) / Performance Level

Y1 Y2 Y3 Y4 Y5 Y6 Y7 Y8 Y9 Y1

Inspections (Power On) Inspection of varimetric regulator (cos phi set-up, delay, C/K, steps) n n n Check current (A) at the general incomer to the capacitor bank n n n Check current at incomer to each step with forcing of step n n n Check THDU, THDI (rate of voltage and current harmonic distortion) n n n Inspections (Power-Off and after safe "consignation") Check capacitors are discharged after lock-out n n n Clean / dust removal from ventilation system and the whole of the bank n n n Check condition of components (capacitors, switches, and fuses) n n n Check capacitance values with a capacitance meter n n n Spare Parts Secure: Parts commonly used in corrective maintenance interventions Fans, Filters Contactors Transformers Circuit breakers or LV Fuses

SUBSTATION - Civil Table "ROOF"

Preventive maintenance activities Minimal Frequency, Performance Level (years)

Y1 Y2 Y3 Y4 Y5 Y6 Y7 Y8 Y9 Y1

Safety line system on roof Certified Inspection n n Roof Visual inspection and gutters cleaning n n n Pavement and cable trenches Cleaning pavement and cable trenches n n n n n n n n n n External walls Visual inspection and wall cleaning if needed n n n n n Ventilation grilles compressed air ventilation louvers cleaning n n n n n n n n n n External pavement High pressure wash for moss and dirt removal n n n n n n n n n n

ASHE20-1068

FINAL (100% design) ELECTRICAL SYSTEM ORDINARY MAINTENACE ANNEX Page 4 of 4

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