Tunnel lighting, or T-lighting, is the lighting system designed specifically for tunnels.
Definition:
Tunnel lighting, or T-lighting, is the lighting system designed specifically for tunnels. It involves the installation of luminaires, light fixtures, and control systems to provide proper illumination throughout the tunnel.
Uses/benefits:
Tunnel lighting serves several uses and provides various benefits, including:
1. Enhanced Visibility: The primary purpose of tunnel lighting is to provide sufficient illumination for tunnel users, ensuring clear visibility of the road, signage, and potential hazards. This improves safety and reduces the risk of accidents.
2. Reduced Glare: Tunnel lighting is designed to minimize glare, which can be caused by the transition from bright exterior lighting to the relatively darker tunnel environment. Properly designed lighting systems help maintain consistent and comfortable lighting levels.
3. Improved Traffic Flow: Adequate lighting in tunnels helps drivers maintain their speed and lane discipline, leading to smoother traffic flow and reduced congestion.
4. Pedestrian Safety: Tunnel lighting is essential for the safety of pedestrians using tunnels or underground walkways. It ensures proper visibility of pathways, stairs, and other pedestrian facilities.
5. Emergency Situations: Well-designed tunnel lighting systems incorporate emergency lighting features, including backup power supply and intelligent control systems, to ensure continued illumination during power outages or emergency situations.
6. CCTV Monitoring: Tunnel lighting often integrates with closed-circuit television (CCTV) systems to provide clear visibility for surveillance and monitoring purposes.
7. Energy Efficiency: Modern tunnel lighting systems are designed to be energy-efficient, employing LED lighting technology, intelligent controls, and sensors to optimize energy consumption and reduce operational costs.
Specifications:
Specifications for tunnel lighting systems can vary depending on tunnel length, traffic volume, safety standards, and project requirements. Some common specifications include:
1. Illuminance Levels: The lighting system should meet minimum illuminance requirements, specified in lux (lx), to ensure adequate visibility for different areaswithin the tunnel, such as roadways, pedestrian areas, and emergency exits. During drilling, mucking, and scaling, there must be a minimum of 50 lux at tunnel and shaft headings. For effective and secure work, a minimum of 30 lux must be given when mucking is done with tipping wagons running on trolley tracks. There must always be at least illumination of 10 lux in any region of the tunnel, including areas outside of approach roads, etc (IS: 4756- 1978).
2. Uniformity: The lighting system should provide uniform illumination throughout the tunnel to avoid abrupt changes in lighting levels and minimize visual distractions.
3. Glare Control: Specifications should include measures to control glare and ensure that the lighting system does not cause discomfort or impairment to drivers or pedestrians.
4. Color Rendering: Tunnel lighting should have high color rendering properties to ensure accurate perception of colors, especially for traffic signs and safety markings.
5. Maintenance: Specifications may include requirements for ease of maintenance, such as accessible luminaire installation, modular design, and monitoring systems for lamp failure detection.
6. Power Supply: The lighting system should have appropriate power supply arrangements, including backup power sources, to ensure uninterrupted lighting operation.
7. Compatibility with Tunnel Infrastructure: Specifications should consider the compatibility of lighting fixtures with tunnel infrastructure, including mounting methods, corrosion resistance, and protection against vibration and moisture.
Types:
There are various types of tunnel lighting systems available, which can vary in terms of the lighting fixtures, mounting methods, and control systems. Some common types include:
1. High-Pressure Sodium (HPS) Lighting: HPS lamps were traditionally used in tunnel lighting due to their high luminous efficacy. However, they are being phased out in favor of more energy-efficient alternatives.
2. Light-Emitting Diode (LED) Lighting: LED lighting has become the preferred choice for tunnel lighting due to its energy efficiency, long lifespan, and flexibility in color temperature and control options.
3. Linear Fluorescent Lighting: Fluorescent lamps, such as T5 or T8 tubes, are also used in tunnel lighting. They provide good lighting performance, high efficacy, and a wide range of color temperatures. However, they are gradually being replaced by LED technology due to its superior energy efficiency and longer lifespan.
4. Induction Lighting: Induction lamps are another option for tunnel lighting. They offer long life, high efficiency, and good color rendering. However, they are less commonly used compared to LED and fluorescent lighting due to their higher initial cost.
5. Smart Lighting Systems: Advanced tunnel lighting systems incorporate smart lighting technologies, such as sensors, dimming controls, and adaptive lighting algorithms. These systems adjust the lighting levels based on real-time conditions, such as traffic flow, ambient light, and weather conditions, to optimize energy consumption and enhance safety.
List of the Some standards related to the illumination of Road tunnels: