5. Public Lighting Installation notes in english

 

5. Public Lighting Installation

Public lighting installations are essential for outdoor spaces, streets, highways, and other public areas to ensure safety, security, and visibility during the night. These installations are designed to provide adequate lighting to prevent accidents and enhance the aesthetic appeal of public spaces. Let’s break down each topic in more detail.

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5.1 Classification of Outdoor Installations (Streetlight / Public Lighting Installation)

Public lighting installations can be classified based on their location, function, and the type of lighting used. Here’s a breakdown of some common classifications:

1. Street Lighting:

   • These lights are installed along roads and streets to illuminate traffic lanes, pedestrian paths, and intersections.
   • Their main purpose is to enhance road safety, prevent accidents, and provide security during the night for vehicles and pedestrians.

2. Park and Garden Lighting:

   • Lighting used in parks, gardens, and recreational areas to ensure safety and create a pleasant environment for people during the evening.
   • These lights are designed for aesthetic purposes as well as security.

3. Floodlighting:

   • Large powerful lights used for lighting up large outdoor areas like stadiums, parking lots, and building facades.
   • They are typically used for both security purposes and creating a striking visual effect at night.

4. Architectural Lighting:

   • Lights installed on or around buildings to highlight architectural features.
   • These lights help enhance the building’s appearance at night, making it more attractive and visible.

5. Decorative Lighting:

   • Lighting used for decoration in public places, such as during festivals or special events.
   • These lights add beauty and ambiance but may not serve functional purposes like streetlights.

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5.2 Street Light Pole Structures

The streetlight pole structure refers to the physical frame or support that holds the streetlight and ensures it remains stable and properly positioned for effective illumination. There are several types of pole structures used in street lighting:

1. Materials Used for Poles:

   • Steel Poles: These are the most commonly used for street lighting due to their strength, durability, and ability to withstand harsh weather conditions.
   • Concrete Poles: Used for larger applications or where extra durability is needed, such as in areas with high wind loads.
   • Aluminum Poles: Lightweight and resistant to corrosion, these are sometimes used for specific applications but are not as strong as steel or concrete poles.
   • Wooden Poles: In some rural or less developed areas, wooden poles may still be used due to their lower cost, but they are generally less durable and require more maintenance.

2. Types of Streetlight Poles:

   • Straight Poles: Simple vertical poles used in most street lighting applications.
   • Decorative Poles: Often used in parks or historical areas for aesthetic purposes, these poles may have special designs.
   • Double Arm Poles: Poles with two arms for mounting two lights in opposite directions, often used in wider roads.

3. Height of Poles:

   • The typical height for streetlight poles ranges from 4 meters to 12 meters, depending on the width of the street and the required level of illumination.

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5.3 Cables, Recommended Types and Sizes of Cable

When designing public lighting installations, selecting the correct type and size of cables is crucial to ensure efficiency, safety, and longevity. Here’s what you need to know:

1. Types of Cables:

   • Underground Cables: These are used for underground installations, especially in areas where overhead cables may be unsafe or unsightly. They are more expensive but safer and more durable.
   • Aerial Cables: Used for overhead installations, these cables are typically supported by poles and are commonly used for street lighting.

2. Recommended Types of Cables:

   • PVC Insulated Cables: These are the most common type of cables used in street lighting installations due to their low cost, ease of installation, and resistance to corrosion.
   • XLPE Cables: Cross-Linked Polyethylene (XLPE) cables are used in applications where higher durability and heat resistance are required.
   • Armored Cables: In areas with higher risk of physical damage to cables, armored cables with protective layers are recommended.

3. Size of Cables:

   • The size of the cable depends on factors like the distance from the power source to the light, the current load, and the voltage drop.
   • Cable Sizing: Commonly used cable sizes for street lighting range from 2.5mm² to 6mm² for smaller installations. Larger installations may require cables of 10mm² or more.
   • The cable size is selected based on the total load (in amperes) of the lighting circuit and the voltage drop allowed (usually less than 3%).

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5.4 Control of Street Light Installation

Controlling streetlight installations involves managing the operation of the lights to ensure they are switched on at night and off during the day to save energy. Different control methods include:

1. Manual Control:

   • Lights are turned on and off manually by a technician. This is less commonly used due to the high labor cost and the need for frequent monitoring.

2. Automatic Control (Photocell or Timer):

   • Photocells: These devices automatically detect daylight and turn on the lights when it gets dark and off when daylight returns. Photocells are commonly used for street lighting control.
   • Timers: These can be set to turn lights on or off at specific times, although they do not adapt to changing daylight conditions like photocells.
   • Dimmers: Some advanced streetlights have dimming features that reduce light intensity during late-night hours when fewer vehicles and pedestrians are on the roads, saving energy.

3. Centralized Control Systems (Smart Street Lighting):

   • Smart Lighting: A more advanced solution that allows for the remote control and monitoring of streetlights. These systems can automatically adjust lighting levels based on traffic, weather, or even time of day.
   • Energy Management Systems (EMS): These systems help monitor energy consumption and adjust lighting levels to minimize energy usage, thereby reducing costs and environmental impact.

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5.5 Design, Estimation, and Costing of Streetlight

Designing and installing street lighting involves several steps:

1. Designing the Lighting Layout:

   • Illumination Levels: The first step is determining the required illumination levels for the street. This depends on factors like the road type (residential, arterial, highway), traffic density, and safety needs. Typical illumination levels are measured in lux (lumens per square meter).
   • Spacing of Poles: The distance between poles depends on the pole height and the desired light coverage. For example, poles are usually spaced between 25 to 35 feet apart.
   • Light Distribution: The type of light fixture and its distribution pattern must be selected to ensure uniform lighting and minimize shadows.

2. Estimating the Cost:

   • Material Costs: The cost of materials includes poles, light fixtures, wiring, and underground cables.
   • Installation Costs: Labor charges for installing the poles, wiring, and connecting the streetlights to the power grid.
   • Maintenance Costs: Ongoing costs include periodic replacement of bulbs, cleaning, and repair of equipment.
   • Energy Consumption: Estimating the annual energy costs is important for long-term budgeting.

3. Costing:

   • The total cost is a combination of material, labor, and energy costs, as well as overheads for safety measures, permits, and any legal or environmental fees.
   • It’s also important to include the potential future cost for upgrading the system to more energy-efficient lighting (such as LED lights) or adding smart control systems.

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5.6 Preparation of Tenders and Abstracts

When street lighting projects are being planned, tenders are used to invite bids from contractors. Preparing tenders and abstracts is a critical part of the process:

1. Tender Preparation:

   • Tender Notice: The project is advertised to attract qualified contractors. The tender notice will detail the scope of work, specifications, timelines, and submission deadlines.
   • Tender Document: This includes all the necessary details about the project, including design, technical specifications, safety requirements, and terms and conditions.
   • Bidding Process: Contractors will submit their proposals based on the provided specifications and estimated costs. The bid should include the total cost, proposed materials, and the contractor’s qualifications.

2. Abstract of Tenders:

   • An abstract of tender is a summary document that compiles all bids received for the project. It compares the different contractors' proposals to evaluate the most competitive and feasible option.
   • The abstract usually includes details such as bid amount, proposed timeline, material cost, labor cost, and any additional provisions.

3. Selection of Contractor:

   • After reviewing the tender proposals, the best contractor is selected based on criteria such as cost, experience, reputation, and compliance with safety and regulatory standards.