METHOD STATEMENT FOR 95KWp ON-GRID SOLAR SYSTEM
The "Method Statement for 95KWp On-Grid Solar System" by QHSE Documents provides a comprehensive guide for the safe and efficient installation of a solar power system. It outlines detailed procedures, safety measures, and quality controls to ensure compliance with industry standards while maximizing energy efficiency and environmental benefits.
1.0. Purpose
To define the general sequence of events, interfaces, and responsibilities relating to the installation of an on-grid solar system
2.0. Scope
This Method Statement for Installation of an On-grid Solar System defines the sequence, quality procedures, and health, safety & environment (HSE) requirements to be followed to implement the activity.
3.0. Supervision & Responsibilities
3.1. Project Manager
3.1.1. The Project Manager will be responsible for the overall implementation of the project and safety.
3.2. Site Engineer
3.2.1. The Site Engineer will be responsible for overall supervision on site. He will organize his team for the proper implementation of the project as per schedule and execute the work according to the plan and specifications. He is also responsible for enforcing the HSE plan, explaining the ways and means to carry out work safely and effectively in order to fulfill the objective of the HSE policy.
3.3. Site supervisor
3.3.1. The Site supervisor is responsible for the site execution. He will check/monitor all the site activities. He will control the manpower, materials, and equipment needed on site. He will counter-check the layout of structures and each elevation prior to proceeding to the further activities and he will record the daily activities done on site for record purposes. Also, he will be responsible for ensuring a safe working environment at all times and applying of required PTW.
3.3.2. Execute the works by the approved plan, QC requirements, and HSE plan
3.3.3. Arrange and follow up materials needed on site.
3.3.4. The Safety Officer shall monitor all work activities and strictly enforce the safety PPE requirements and HSE plan to wit;
3.3.5. Control, supervise and record toolbox meeting.
3.3.6. Inspect approved or rejected engaged resources.
3.3.7. Ensure that all HSE requirements are met and implemented while executing the works.
3.3.8. Notify the person in charge on-site if deviation and/or corrective remedy action are to be applied before and while executing the works.
3.3.9. Ensure that recommendations for workplace precautions are followed up strictly.
3.3.10. Stop any or all works in the case specified recommendations/observations that were not followed up by the construction team.
3.3.11. Responsible for any application of required PTW.
4.0. Construction of solar system on rooftop
When installing solar panels on rooftops, several structural considerations must be thoroughly investigated and analyzed. Solar panels can be installed on both new and existing buildings. For new construction, solar panels can be integrated efficiently and affordably at the design stage. The structural system can be engineered to accommodate the additional load from the system’s weight (dead load), snow accumulation, and wind uplift. For existing buildings, the added load from the solar panels requires careful analysis. In many regions, building codes have been updated to reflect changes in base snow load requirements, so these must be verified in addition to the weight of the solar panels. Future load considerations must account for all structural elements, from the roof deck down to the foundation.
The roof must have the capacity to support a minimum of 6 pounds per square foot of additional dead load from the photovoltaic (PV) system. It is essential to confirm with the building designer and structural engineer that the roof can bear the extra weight and wind loading imposed by the solar system. Additionally, the potential impact on the roofing warranty from placing solar panels on the roof should be reviewed.
There are several types of solar panel mounting systems for rooftops:
⦁ Sloped roof mounting systems: Residential solar installations are commonly found on sloped rooftops. Various mounting options exist for these roofs, including railed, rail-less, and shared rail systems. Each of these requires roof penetration or anchoring, either into rafters or directly into the roof decking.
⦁ Ballasted systems: In cases where roof or ground penetration isn’t feasible, ballasted structures are used. Concrete blocks are distributed across the installation site to secure the panels in place, preventing wind uplift and movement without damaging the roof or ground.
Solar panel mounts, typically made of galvanized steel, aluminum, or stainless steel, are securely attached to the roof. Most rooftop solar panel mounts feature two horizontal mounting rails fixed to the roof with anchors.
The roof must provide optimal conditions for solar panel performance. Roofing systems are designed to direct water off the roof and away from the building. However, improper installation of solar panels can disrupt this water flow, causing water to pool or flow backward, which could lead to leaks. Repairing a roof with solar panels installed is often more challenging.
Proper measures for installation include:
⦁ Hot-dip galvanizing all steel materials.
⦁ Ensuring bolts are properly secured.
⦁ Maintaining panel levelness.
⦁ Regular cleaning of solar panels for optimal performance.
⦁ Structural Analysis for Solar Panels on Roof Slabs
A visual inspection is required to assess:
⦁ Types of structural defects.
⦁ Signs of material deterioration.
⦁ Structural distress or deformation.
⦁ Modifications or misuse that could lead to overloading.
When installing arrays of solar panels on an existing roof, the mounting system and panels introduce concentrated loads from wind, seismic activity, and snow at specific points on the roof structure. The weight of a ballasted photovoltaic system typically ranges from 4.5 to 6 pounds per square foot, depending on the panel’s tilt and the installation height. Thin-film solar panels weigh less but require more coverage due to lower efficiency.
Before installing a rooftop solar system, it’s critical to assess the roof structure’s ability to bear the additional load or determine if modifications are needed. A prescriptive pathway can expedite the permitting process for installations that meet specific criteria, such as:
⦁ Building type, roof structure, and material.
⦁ Loading limits (not to exceed 4.5 pounds per square foot, with panels and mounting equipment averaging 2–4 pounds per square foot).
⦁ Height limits (no higher than 18 inches above the roof).
⦁ Positive attachment to the roof structure, rather than relying on ballasted systems.
5.0. Fixing Cable trays
⦁ Cable trays and ladders will conform to the specifications outlined in the approved material submittal.
⦁ All accessories, such as bends, intersections, risers, reducers, and elbows used with the cable trays and ladders, will be sourced from the same manufacturer as the trays and ladders.
⦁ Before starting any tray and ladder installations, complete coordination with other mechanical services will be conducted to avoid interference or disruption of service.
⦁ Tray and ladder routes will be marked on the ceiling before the installation process.
⦁ Each run of cable trays and ladders will be completed before any cables are installed. The runs will be properly aligned, leveled, and securely fastened to the ceiling or wall.
⦁ Supports will be provided to prevent strain on cables entering or exiting the trays. Cable trays passing through partitions and walls will be protected by non-combustible, fireproof barriers.
⦁ All sharp edges, burrs, and projections will be removed before fixing the trays and ladders. Approved suspension rods or steel angle brackets will be used at intervals not exceeding 1.5 meters, as shown on the approved drawings. Joints will be positioned as close as possible to tray or ladder supports.
⦁ Trays and ladders, including tees, bends, and crossings, will be installed with radial fittings to accommodate cable bending standards.
⦁ A minimum clearance of 250mm will be maintained between the top of the tray and the ceiling.
⦁ Cables will be arranged in a single layer, evenly spaced, with a minimum spacing of two diameters between adjacent cables or configured in trefoil formation for single-core cable circuits.
⦁ Wherever possible, cable trays will directly support the cables without cleats or saddles. However, custom-made straps, cleats, or saddles will be used to maintain a neat and organized arrangement of cables. For vertical tray installations, or where trays do not directly support the cables, load-bearing cable cleats or saddles will be employed and securely attached to the tray. The manufacturer’s recommendations will be followed when selecting cleats or saddles based on the specific application.
⦁ Earthing jumpers will be installed on trays and ladders between sections, as required, to ensure effective electrical continuity, regardless of whether a separate protective earth conductor is needed.
6.0. Laying of DC and AC Cables
⦁ After completing the proper installation of cable trays and C-channels, we will begin pulling armored cables (inverter to SMDB, SMDB to Meter Cabinet, and Cabinet to Point of Connection) and DC cables (Panel to Panel and Panels to Inverter) carefully to avoid any damage. Once pulled, the cables will be securely tied to the vertical C-channels using cable cleats before being terminated to MDBs and SMDBs through cable glands.
⦁ Install cables strictly according to the consultant-approved shop drawings and manufacturer’s instructions.
⦁ Lay cables in one continuous length unless otherwise specified. Obtain approval from the Engineer for any through joints or where the required length exceeds practical drum size.
⦁ Use appropriate equipment such as drum stands, drum axles, fairleads, rollers, and cable stockings, as recommended by the cable manufacturer.
⦁ Ensure that cables are installed in an orderly manner and can be easily withdrawn if necessary.
7.0. Cable Termination and Glanding
⦁ All joints, terminations, and landings must be performed by qualified personnel, using components and workmanship recommended by the cable manufacturer, and in line with local authorities and CLIENT recommendations.
⦁ Cut cable ends just before jointing or terminating, and seal any cables left unconnected for more than 24 hours to prevent moisture ingress.
⦁ Strip cables only to the minimum length required for connection, ensuring no conductor is exposed after termination. Twist the strands together, ensuring no damage to the strands and that their number is not reduced. Secure all strands at the termination point.
⦁ Clean the armor thoroughly before jointing or terminating. For equipment and switchgear that lack integral cable clamping terminals, use compression-type lugs for bolted terminal connections.
⦁ Do not group more than three cores at any clamping terminal or bolted connection.
⦁ Mark cable conductor phasing or core identification at both ends of all cables.
⦁ The contractor is responsible for testing all cables before making final connections.
⦁ Where cable sheaths serve as earth continuity conductors, ensure glands provide the necessary low-resistance path for fault conditions.
⦁ Use approved cable lugs, compression types, and proprietary tools for all plant cable connections.
⦁ All outdoor glands, or those specified elsewhere, must be weatherproof and watertight. Gland manufacturers must be approved, and glands should be suited to the cable type and location.
⦁ Earth tags must be fitted to each gland during assembly, before attaching the lugs.
⦁ Ensure that cable glands are ordered in kit form, including earth tag, shroud, locknut, and neoprene seal.
8.0. Fixing of MDB / SMDB / Energy Meter Cabinet
⦁ All materials and equipment will be supplied and installed according to approved shop drawings, material submittals, and the proposed method statement.
⦁ Provide the approved documents to the switchgear supplier to ensure product manufacturing complies with the approved material and technical submittals, with delivery to the site as per the agreed schedule.
⦁ Panelboards will comply with local and CLIENT requirements, by the "Standard for Panel Boards" and cabinet/box standards, and be rated at 400/230V, 3-phase, 4 wires, 50Hz.
⦁ All equipment will be installed following the manufacturer’s recommendations, installation instructions, site requirements, and the approved project schedule.
⦁ Each panel will feature a nameplate with the manufacturer's name, panel type, and ratings.
⦁ Samples of DB enclosures (surface and flush) with circuit breaker arrangements will be submitted for Consultant/Client inspection. Installation will proceed once approval is obtained.
⦁ Distribution boards will be fully wired and tested at the factory before delivery to the site. Bracing will be provided to prevent damage during handling and shipping.
⦁ Distribution boards will incorporate plug-in type miniature circuit breakers with tripping characteristics B, C, or D, as required for lighting, power, or motor loads, in line with approved drawings.
⦁ The interior will be designed for easy replacement of circuit breakers without disturbing adjacent units or removing main bus connectors.
⦁ After installation, all exterior and interior steel surfaces of the panel boards will be cleaned, and dust, rubbish, or concrete splatter will be removed using brushes or vacuum cleaners.
9.0. Distribution Boards
⦁ The fixing height for DBs will be 800 mm from the finished floor level, as per CLIENT regulations, or no higher than 2 meters to the top of the panel boards from the floor.
⦁ As mentioned, a sample SMDB must be approved by the Consultant before installation begins.
⦁ DBs may be wall- or floor-mounted, depending on the board frame size. All trunking arrangements will be by the approved shop drawings.
⦁ The wiring, cabling, and dressing of DBs will follow similar procedures as outlined for DB connections, with all connections accessible from the front.
10.0. Tools &Equipments
⦁ Typical Equipment (whenever required)
⦁ Mobile Crane and Lifting Gear.
⦁ Trailer Truck
⦁ Man lift
⦁ Manual Hydraulic lift
11.0. Emergency Procedures & ERTS.
⦁ Emergency exit and assembly point made for excavation.
⦁ Fire extinguishers are provided where the hot work is applicable.
⦁ Easy access is provided with a ladder with handrails.
12.0. Emergency Contact Numbers
⦁ Project Engineer
⦁ HSE Engineer
⦁ Police
⦁ Ambulance
⦁ Fire
13.0. Manpower Resourcing
⦁ Project Engineer
⦁ Technician
⦁ Help
14.0. Attachment
⦁ Risk Assessment
15.0. Inspection & Test Plan
All work-in-progress shall be inspected by the designated project staff and the site resident engineer/site clerk of work at various inspection points as per the relevant project quality plan. Refer to the attachment.
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