Method Statement for ELV (Extra Low Voltage) System – Underground External

method statement elv system

What is Method Statement for ELV (Extra Low Voltage) System -Underground External?

This Method Statement for ELV (Extra Low Voltage) system defines the procedures for the installation of external underground ELV services up to tie-in point/access control panels of the building ensuring that job execution complies with the Project Specifications, Quality, Health & Safety standard practices.

The scope of this method statement includes:

  • Methodology for installation of all the electrical system containments for ELV systems externally which comprise of a variety of sub-systems like:
    Data transmission IT Networks; Local Area Networks (LAN) using Fiber Optic, Copper or Wireless
    CCTV/ IP Surveillance
    Building Management System (BMS)
    Sensors & Alarm System
    Vehicle Access Control
    Telephone: Voice & Video Intercom
    Door Access Control
    Lift Access Control
    IP Clock System
    Lighting Control System
    Toilet Alarm System
    HVAC Control
    Fire Fighting System – Fire alarm system
    Public Address Broadcasting
    Disabled Toilet Alarm and Call System
    Voice Evacuation System
    Tour Guard Patrol
    Public Address System/Call System
    Parking Management
    Audio Visual System (Auditorium/ Conference Halls)
  • Equipment, approved documents, and approved materials used
  • Checklists, Inspection, and Test Plans as part of the Project Quality Plan
  • Quality Control Procedure and Quality Management System for ELV services
  • HSE Assessment & Job Hazard Assessment, Construction Risk Assessment 
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The work sequence of the ELV system

The following methodology is for UPVC/HDPE duct installation, cable laying for underground extra-low voltage system (ELV) up to tie-in point/access control panels. 
MEP team will only come in after receiving clearance from other disciplines to start the underground duct installation and cable laying.

Delivery of Materials, Storage and Handling

  1. The wooden drums will be always carried vertically. They will be fixed and properly chocked with care on the vehicle, on the wagon and on the ship, in order to avoid any exterior chocks.
  2. The unloading and the different handling will be done carefully with lifting equipment’s. – In case of handling with a crane, an axle is used in crossing the drum centre, lifted from both ends by two slings. It will have a length equal, at least, to the width of the drum. It is prohibited to put the slings on the lags.

In case of handling with a forklift truck, the drum is put vertically with care on the forks, never let a drum fall during all kind of unloading, and do not place any weight on the drums.

  1. When the cable drums are arriving on-site, it will be checked especially.
  2. The good order of the lagging and of the end caps of the cables (breaking of a wooden lag could tear the outer
  3. Deliveries will be Inspected and handled at the site area according to the given instructed requirements.
  4. All UPVC/HDPE ducts, fitting accessories, utility structures, and cables will be covered and stored above grade in a secure and protected location in order to be protected from climate, dust, and entrance of debris and will be codified for easy traceability.
  5. Ensured that the proposed storage area for the materials is cleaned.
  6. Separate areas in the storage zone will be marked for different materials.
  7. Ensured that the material is stored in a shaded area to protect it from exposure to direct sunlight.
  8. Ensured that the lifting equipment is adequately rated for the specked weight (shown on the rating plate) and fit for purpose.
  9. Verify that the bracing & supports are provided to prevent damage during transit, lifting, or unloading.
  10. All materials received at the site will be inspected by the Consultant and Contractor’s QC inspectors/QC Electrical inspectors with the corresponding Material Inspection Request (MIR) issued.
  11. Ensured the drums to be moved in an upright position and the fork will be longer than the width of the drum. When moving the drums, tilt the truck mast so that the drum remains in the fork and the points don’t touch the ground. Raise the forks of the forklift at least 6-8 inches from the ground surface.
  12. Don’t release the forks until the truck has stopped completely. Keep sufficient space between the drums so that forks don’t damage the other drum

Drum Transportation, Unloading and Storage

  1. During transportation, the cable drums should not be kept in a flat position; it crushes down the layer of the cable, resulting in breakage
  2. The cable drums should always be kept in an upright position and be tied with a chain or belt with wooden blocks that should be kept in between the flanges of each drum to avoid any jerks/ movements during transportation.
  3. While unloading trucks it is important that the cable drum should not be dropped directly on the floor.
  4. The weight of drum & cable may cause deflection of drum flange resulting in flattening, deformation, or damage of cable.
  5. The drum will be rolled from the truck on to receiving platform, which should be at the same height as the tailgate of the truck. An alternate is to use a forklift to unload drums from the truck
  6. The drums should always be stored in an upright position. The storage of drums in an alternative position can lead to winding defects.
  7. If storage place is limited and it becomes necessary to stack, then stack the completely wrapped on their flanges. Stacking is allowed only for the drums whose flange diameter is 1250mm or less. Do not store drums on flat flanges.
  8. The cable drums will be stored on a well-drained, hard surface so that the drums do not sink in the ground causing rot and damage to the cable drums. The paved surface is preferred, particularly for long term storage.
  9. The drums will always be stored on their flanges, and not on their flat sides.
  10. Both ends of the cables should be properly sealed to prevent the ingress/absorption of moisture by the insulation during storage.
  11. Protection from rain and sun is preferable for long term storage for all types of cables.
  12. There should also ventilation between cable drums.

Installation Procedures for Underground External ELV (Extra Low Voltage) System

Excavation

Excavation and preparation of trenches for the installation of duct banks and other underground utility services will be in accordance with the Project Specifications.

  1. Permit to Work (PTW) will be raised for the excavation clearly mentioning the location of work, size of excavation, and levels.
  2. The area of excavation will be cordoned off using safety devices.
  3. The size of the trench will depend on the number of circuits and conditions of the site.
  4. The depth of excavation for the trench of the underground ELV cables will depend on the number of UPVC/HDPE pipes as per the approved shop drawings.

Clearing and Grubbing

  1. The Contractor will excavate and remove surface material such as debris, windblown sand, vegetation, and any other unsuitable material in the areas and to the thickness instructed by the Client’s representative. Clearing and grubbing will be restricted to removal of surface material and debris and will not include the excavation of natural ground unless directed by the Client’s representative.
  2. The removed material will be loaded and transported to an approved dumping area.
  3. All surface objects, trees, stumps, roots, and other protruding obstructions not designated to remain will be grubbed and cleared.
  4. In areas inside of the grading limits of cut and embankment areas, stumps and nonperishable sold objects will be cut off not less than one meter below the subgrade level in the area.

Pre-Installation

Before the commencement of installation, the following are required to be carried out:

  1. Drawing for external ELV work will be approved and will be coordinated with other services.
  2. Proper access will be provided as per the approved program.
  3. The location/area will be ready for site installation.
  4. Prior to the installation, the area where the items to be installed will be inspected
  5. Prior to the installation, check all cabling as per approved wiring detail drawings.
  6. Mark the device/panels location and leave enough length of cable at both ends for termination.
  7. All installation details will be agreed upon with the Engineer and will be subject to his approval prior to the commencement of work. The Specialist will obtain an inspection certificate from the manufacturer or its authorized representative towards the satisfactory installation of the system.
  8. Coordination drawings will include multi-discipline activities:
    1. Underground Services and Substructure
    2. External Utilities and Final Connections

Excavation and Preparation of Trench

  1. Excavation and preparation of trenches for installation of duct banks and other underground utility services will be in accordance with the Project Specifications
  2. If dewatering is required for trench preparation, this will be performed
  3. Trench depth to be excavated will be as per IFC drawing detail unless otherwise specified.
  4. Clean trenches of organic material, root, trash, lumber, and debris. etc., prior to duct installation.
  5. Place approved bedding material to the extent necessary for establishing the correct elevation at all locations where the bottom has been excavated below indicated grade.
  6. Prepare and compact the trench bottom such that the duct pipes can be placed to the specified line and grade, with full uniform bedding, when required.
  7. Final invert level elevation will be discussed and finalized by the site engineer based on the approved shop drawings.
  8. The trench preparation will be checked for the required depth, width, elevation, slope, and will be free from rock, large stones, and any other sharp projections.

Trench Installation

  1. ELV cables installed inside UPVC/HDPE underground duct will be free from any damages.
  2. Trench sizes will be made as per the approved IFC drawings and as per the suitable trench size.
  3. Inspection by the Consultant Representative has to be done for each stage.
  4. Place approved bedding material to the extent necessary for establishing the correct elevation at all locations where the bottom has been excavated below indicated grade
  5. Good coordination with the civil team has to be done.
  6. Distance between the UPVC pipes during installation should be respected.
  7. The bottom of the cable trench will be covered, to a depth not less than the diameter of the largest cable, with a bedding layer of sand or fine soil.
  8. Draw rope of 6mm diameter to be provided throughout all the ducts.

UPVC/HDPE Duct Installation for Underground ELV Cables

  1. It will be ensured that all work is completed and the site is cleared from all disciplines to install ELV cables.
  2. Prior to the installation of duct-pipes, the trench preparation will be checked for the required elevation, slope, and free from rock, stones, and other deleterious materials. The installation will not be started until unsatisfactory conditions have been corrected.
  3. Final invert level elevation will be discussed and finalized by an electrical engineer and civil engineer based on the approved shop drawing.
  4. Proper approved materials will be used according to the material submittals: (Submittal References here)
  5. Ducts will not be filled with cables to more than 60% of their capacity. Nylon drawcords will always be left in ducts.
  6. The trench width and size are done as per the approved IFC drawing
  7. The trench should be sand bedded for 100mm for ICT & ELV as per IFC Drawings and then duct separators are used for underground ducts.

Installation Details of ITS Network

  1. The ITS duct banks installed under the carriageway are concrete surrounded by Grade SRC 20 as per IF drawing.
  2. Make joints in ducts and fittings are watertight according to manufacturer-recommended accessories installation method.
  3. Use approved backfill material and provide approved warning tape: 200-300 mm as per IFC Drawing.
  4. Make joints in ducts and fittings watertight according to manufacturer written instruction.
  5. Stagger the joints of multiple layers of conduits so as not to create a weak point in the duct run
  6. Bell mouths are installed at each end of the duct pipe
  7. Wipe the duct dry and clean before joining. Apply full even coat of suitable adhesive to the entire area inserted in the fitting. Allow joint to cure for 20 minutes, minimum
  8. Install no more than equivalent of two 90-degree bends between pull points.
  9. Duct pits or manholes will be provided at each change of direction and in any case at the distance not exceeding 30 meters. Segregation of services ducts will be maintained as per Project Specifications.
  10. Band ducts together before backfilling.

Installation Details of Telecommunication Network

  1. All the duct route are as per the approved IFC Drawing
  2. Where the ducts are laid under the carriageway, the bottom of the trench to be compacted 95% of MDD or as per by the IFC drawing.
  3. Prepare and compact the trench bottom such that the telecommunication duct pipes can be placed to the specified line and grade, with full uniform bending, when required.
  4. Draw rope of 6mm diameter to be provided throughout all the ducts.
  5. All ducts to be tested with brush and mandrel as per Project Specification after final compaction

Installation Details of ICT & ELV Network

  1. The ELV duct banks will be installed under the carriageway with a protection slab of concrete of grade SRC 30.
  2. Make joints in ducts and fittings are watertight according to the manufacturer-recommended installation method.
  3. Provide 50mm horizontal spacing and 50mm vertical spacing between duct bank/ conduits installed in the same trench and a clearance of at least 300mm from all other services.
  4. Install duct spacers to keep conduits locked together and to prevent sagging and deforming of ducts. Secure spacer to ducts to prevent displacement during concrete pouring.
  5. Terminate duct runs with end cap/ duct coupling for new future extension.
  6. Install pull-string inside each empty duct run with enough slack at each end for future cable & cable tray installation works.
  7. Seal both ends of duct bank with plastic end cap/ sealing plug which will be left in place until cable laying work begins to avoid dirt and foreign materials from entering during and after concrete pouring
  8. Prior to concrete pouring, perform the inspection with the Consultant Representative for approval before proceeding further.
  9. Immediately after placing of concrete, pull through each duct a mandrel not less than 300mm long and of a diameter of 6mm less than the internal diameter of the duct, followed by a stiff bristle brush to remove all sand, earth, and other foreign matter.
  10. Work the mandrel through the ducts carefully to avoid disturbing or damaging ducts where concrete has not set completely. Pull a stiff bristle brush and a swab to remove water, mud, and fine sand through each duct immediately before pulling in cables.
  11. All duct banks at the limit of works will have end caps installed to prevent unwanted materials from entering the duct and the chamber network and assisting future connection and network extension.

Installation details of Security System Network

  1. All ducts under the carriageway will have concrete slab protection according to Security System Standards.
  2. Provide suitable pull string in each empty duct except sleeves and nipples.
  3. Use suitable caps to protect the installed vacant duct against the entrance of dirt and moisture.
  4. After sanding, warning tapes for the duct banks and cables are provided as per the approved shop drawing.
  5. The proposed location of ducts and manholes for the project is tentative only. Its the contractor’s responsibility to finalize the location of the duct at the site, in coordination with other new services.

Installation of Underground ELV Cable Through Duct

  1. Before cable pulling commences, the actual length of the route will be measured and checked to ensure the adequacy of the provided cable length. The system will be installed by a contractor licensed to carry out such installations and be in accordance with the project specifications.
  2. All loose materials will be removed from the duct before the start of cable pulling.
  3. Approved cable pulling lubricant will be used while cable pulling in to the duct banks or UPVC/HDPE conduit if required.
  4. Before pulling operations begin a communications link will be established between the feed and pull manholes (and any intermediate manholes the cable may pass through).
  5. Once the cable appears in the pull manhole it may be pulled over a sheave or quadrant block as long as the diameter of the sheave or block meets the cable’s minimum bend radius under tension. No attempt should be made to inch the cable to its final manhole. This may cause undesirable surges to the end portion of the cable.
  6. It is ensured that the manufacturer’s recommendations for installation of cable pulling are done by proper tools, pulling winch, and concrete protection from mechanical stress.
  7. Cable identification tag will be provided on cables at each entry and exit point of the buried duct and in other such positions to identify and trace the route of the cable.
  8. Ducts including spare ducts will be sealed at the point of entry or exit by approved sealant materials after installation of all cables.

Cable Back Feeding Procedure

  1. Identify the inner duct in which the ELV cable is to be placed. After the correct inner duct has been identified, it will be tied off to keep it from “creeping” as the cable is being pulled into it. Any spare ducts should be capped off so that they do not interfere with the cable pulling operation.
  2. When pulling problems are expected due to long duct lengths, excessive curvatures in the duct, or for other reasons, the cable can be pulled in from two directions.
  3. Attach the pulling line to the cable and position the reel in the same manner as for an end pull.
  4. The pull manhole setup and the feed manhole setup are the same as they were for an end pull.
  5. Communication, lubrication, and cable pulling are all conducted as for an end pull as show below
  6. Before pulling operations begin a communications link will be established between the feed and pull manholes (and any intermediate manholes the cable may pass through).
  7. (If required) At the mid-feed manhole, remove the remaining ELV cable from the reel. The cable will be laid out in a large figure-eight configuration close to the manhole opening. Keep the cable as clean of debris as possible by not figure-eight the cable onto sand or dirt which might adhere to the cable. Sand or dirt clinging to the cable will cause increased pulling tensions. Spreading out a sheet of polyethylene before beginning to figure-eight is one method that will help keep the cable reasonably clean.

a. Underground Warning Tape

  1. The 100mm wide warning tape, detectable type, colored yellow with suitable warning legend describing buried ELV lines. Avoid sharp bends and narrow loops.
  2. Identify underground conduits using underground warning tape. Install one tape per trench at 150mm below the finished grade.
  3. It is ensured to implement all points required by HSE and environments and sustainability before starting the work on site.
  4. Throughout the duct bank execution stage and upon completion, representatives from the Engineer will be invited to carry out inspections of the works.
  5. The contractor will be ensured that his program works are in the designated sequence in accordance with the approved program
  6. Completion of each phase of the works to progress to the next phase will be subject to the approval of the Engineer.

b. Preparations for Backfilling

  1. Before the commencement of any work at the site, the Site Engineer/Supervisor and H & S officer will instruct the field team regarding work method and safety measures in line with the subject method statement.
  2. Safety barriers will be placed on existing structures, services within defined the working zone before and during activities at the site. Sensitive areas will be marked out within or adjacent to works with signage.
  3. For safe operations, all personnel not directly involved with the operations will be kept clear of the working area. A demarcated observation area will be established to enable safe monitoring and observation of the works without encroaching into the working zone.
  4. All personnel needing to enter the working area will need to first inform the available foreman/supervisor in charge of the operation and ensured that prior to entering the works, the flagman is alerted.
  5. Proper lighting will be supplied at the site during night work. Flagman will be aware of blind spots of vehicles and all workers will be provided Reflective Jackets along with necessary PPE.
  6. Necessary dust control and noise reduction measures will be carried out.
  7. The safe observation area will be established at the site covering with safe barricades.
  8. Movement of vehicles or machinery, temporary stockpiling of soil at the observation site’ will be restricted.

Redline Mark-up & As-built

If any changes occur in the cable routes (Non-adherence to the approved shop drawings) then such information will be detailed in the As-Built Drawings with Red Lines.

Testing and Commissioning Method Statement for ELV

A detailed separate electrical method statement for system testing & commissioning of the ELV system has to be developed and submitted.

Quality Procedure of Method Statement for ELV

The Inspection and Test Plan (ITP) for this Method Statement for ELV (Extra Low Voltage) system summarizes various characteristics to be checked. The concerned Site Engineer or Site Supervisor will be responsible to ensure compliance for these operations and the site QA QC ELV Engineer will carry out quality control checks and report the inspection results.

Quality Records

  1. Quality records will be provided as identified in the ITP and maintained as per ISO 9001/Project Requirements and Specifications.
  2. The standard form of records, quality checklists, and QA/QC reports requirements are defined in the Inspection and Test Plans.
  3. Submission of as-built records will be done after completion.

Specific Quality Measurements

  1. All works will be undertaken in compliance with the quality requirements of the Contract and “Project Quality Management Plan”. Where non-conformances are found /identified to demonstrate its conformity. All works requiring inspection and system testing to demonstrate conformity with requirements will be undertaken in accordance with the “Control of Inspection and Testing”.
  2. Where non-conformities are found/identified, they will be addressed in accordance with “Procedure for Control of Non-Conformances”. The quality control activities associated with the works will be conveyed to all personnel involved in the execution of the works by the Project QA/QC Manager prior to the commencement of the work.
  3. The equipment and instruments widely used for measurements on-site will be calibrated and certified. The relevant project documentation will accompany the corresponding equipment and instruments. Necessary internal and external training is provided to the staff carrying out the job to ensure that the quality standards required on the project are met. Skilled and competent personnel are deployed to undertake the job.

Health and Safety Plan of Method Statement for ELV System

Site safety control shall be conducted in accordance with the guidelines stipulated in the attached Risk Assessment.

  1. To ensure that the permit system should be followed according to the HSE Plan
  2. To ensure that the lifting operation should be followed according to the HSE Plan
  3. Copies of 3rd party certificate, drivers/operator’s license vehicle’s registration, and security pass to be submitted to Company safety department before commencing the work.

Personal Protective PPE Requirements

PPE is the last line of defence not the first: however, every contractor should provide adequate suitable, sufficient PPE to protect the workforce wherever possible. As a minimum for all personal during the abutment works will be hat, safety boots, coveralls, goggles and gloves will be provided and used at all times. Additional task specific PPE will be provided and worn in line with risk assessments.

Emergency Response

Emergency response shall be initiated by Authorized Person. Emergency response section in HSE plan shall be followed

In case of an emergency the following actions shall be activated:

  • Stop the activity
  • Call the emergency number for help
  • Provide first aid and call the ambulance
  • Alert site clinic / Nurse/ First aider

Responsibilities

Project Manager

  1. The Project Manager (MEP) will be responsible to manage, execute, complete, and handover the construction activities within approved budgets and resources in compliance with Project Requirements as specified in Project Specifications. He will be overall in charge of implementing the Method Statement for ELV in accordance with QA/QC and HSE requirements.
  2. Responsible for controlling the project’s entire activities & for the overall coordination with the consultant/client.
  3. Ensured that adequate welfare facilities and equipment are provided to the project to avoid injury, health impairment, or damage & provided quality works within the planned time scale.
  4. All responsibilities stated in the Project’s Quality Assurance Plan.

Construction Manager

  1. Organize the site so that work is carried out to the required specifications with minimum risk to men, equipment, and materials.
  2. Coordination with different functions with the project.
  3. Expediting area of concern to achieve project schedule.
  4. Adhere to the project-specific quality management program and HSE requirements.
  5. Delivering the overall works in a safe and timely manner, ensuring conformance with the approved design. Leading the team of engineers and surveyors, guiding them in the delivery of the works. Acquire, allocate, and maintain resources.

QA/QC Manager

  1. Responsible for the work entire quality assurance, quality control & inspection programs
  2. Produce all quality-related documents & reports necessary as requested by the Client/Consultant/Engineer.
  3. Provide written procedures & to coordinate in formalizing the Method Statements for ELV with the Project Manager/ Construction Managers/Site Engineers to describe the job-specific work for each stage/activity.
  4. All responsibilities stated in the Project’s Quality Assurance Plan.

QA/QC Engineer

  1. Responsible for the work of entire Quality Assurance, Quality Control & inspection programs.
  2. Produce all Quality related documents & necessary quality reports as requested.
  3.  Provide written procedures & to coordinate in formalizing the Method Statements for ELV with the Construction Manager/Site Engineers to describe the job-specific work for each stage/activity.

Safety Manager

  1. Manage Safety Engineers and Safety Officers to be in strict conformance with project policies and procedures.
  2. Ensure the safe work method stated in Method Statement for ELV is fully implemented during activity.
  3. Responsible for controlling HSE personnel for effective monitoring of work.
  4. Over-see site safety orientations/inductions, toolbox talks, safety training certifications, job site inspections, working at heights, scaffolding tagging systems are fully functional, rigging, etc.
  5. Report to Project Manager all personal injuries and near-miss incidents (aligned with Safety Engineers / Officers) as well as property damages immediately.  Produce investigative reports and summaries to senior management.

Safety Officer

  1. Provide advice and coordination in line with the project HSE Plan, legislation, and standards in Qatar to workgroups as required/directed.
  2. Input into the preparation and maintenance Risk Register at the project level which will form the basis of risk management on the project.
  3. Monitoring and reporting compliance with the project HSE Plan
  4. Assist with the implementation and monitoring of the project.
  5. Conducting regular HSE inspections and participating in HSE audits.
  6. Reporting as required, HSE incidents, including near-miss events, injuries, and any other HSE issues.

Site Engineer

  1. Adheres to the Project-specific method statements, procedures, inspection programs & HSE instructions to get the activities performed to Client satisfaction with full coordination with the HSE & Quality personnel.         Responsible for ensuring that correct drawings, materials, tools, and equipment are provided on-site.
  2. Liaising with sub-contractors, supervisors, planners, quantity surveyors Send the general workforce involved in the project.
  3. Responsible for planning the work and efficiently organizing the plan and site facilities in order to meet agreed deadlines.
  4. Site engineer is responsible to coordinate with QA/QC team engineers/ inspectors, and for the handover of daily site, progress works report/highlighted drawings & present during the inspection/site visit with QA/QC Inspectors & consultant/client.            

Surveyor

  1. Will be responsible for all survey work and will report to the chief surveyor.

General Foreman

  1. Performed the activities instructed by the Supervisor/Engineer at the site and follow the safety procedures to make it safe for his workers.
  2. In charged to lead the work execution to send the focal point in coordinating with site
  3. Supervisor/Engineer is related to overall site activity, materials, tools, and equipment.

Technician

  1. Carry out installation work as per the concerned foreman’s instructions with all the safety requirements.
  2. The workforce to attend daily toolbox talks, morning task brief briefs prior to starting any works EHS (Environment Health Standard) plans and policies.
  3. Must have a certain amount of experience and expertise that is required when working with high-tech network and security equipment.

Workforce

  1. Supervisor
  2. Foreman
  3. Charge Hand/Supervisor
  4. HSE Engineer/officer       
  5. Surveyor
  6. Plumber
  7. Skilled Labour as per the required work 

Tools and Equipment’s

The operator of the equipment will be certified by a third party and have a valid license/ registration issued by the traffic department.
Spanner Set
Screwdriver set
Marker/whitener & lined
Wooden hammer
Metal cutting saw
Mobile scaffolds
Grinder
Drilling machine
Manlift
Spirit level