The difference between horizontal and vertical illuminance lies in the direction in which the light is measured. Horizontal illuminance measure the light falling on a horizontal surface, such as the ground or a work floor. Vertical illuminance measures light on a vertical surface, such as a container wall, a vehicle side, or a person moving through the port. In ports, both measurements are necessary because safety and operational control depend on multi-directional visibility. This article answers the most frequently asked questions about illuminance in ports and terminals.
Why do ports measure lux both horizontally and vertically?
Activities in a port are not limited to illuminating the ground. Crane operators, truck drivers, and security personnel need to recognize objects, vehicles, and people on vertical surfaces—and horizontal-only lux is insufficient for this.
Complex logistical movements take place in a port, where visibility in all directions is of vital importance. A well-lit roadway says little about the visibility of a passing forklift at eye level. Security cameras also work much better when there is sufficient vertical illuminance, as faces and license plates are then clearly captured.
By lighting So, it's always about a combination of both measurements. A lighting plan that only focuses on horizontal lux does not meet the practical and normative requirements of a modern port area.
What lighting standards apply to ports and terminals?
The European standard EN 12464-2 is leading for ports and terminals. This standard specifies minimum illuminance levels for outdoor workplaces, including both horizontal and vertical values. For traffic routes in ports, a minimum horizontal illuminance of 20 lux generally applies, while work areas require higher values.
In addition to EN 12464-2, sector-specific guidelines also play a role. Consider requirements from port authorities, ISPS security standards for security zones, and additional requirements for ATEX zones where there is a risk of explosion. For vertical illuminance, a minimum of 50 lux at a height of 1.5 meters is often used in work zones, but this varies by application and risk class.
Relevant considerations for lighting standards in ports:
- EN 12464-2 as a basic framework for outdoor workplaces
- Uniformity requirement: the ratio of minimum to average illuminance must not be too low
- Specific requirements for security zones (CCTV-compatible lighting levels)
- ATEX classifications in explosive atmospheres
- Additional requirements from local port authorities or clients
Hoe beïnvloedt de hoogte van lichtmasten de verticale verlichtingssterkte?
Mast height has a direct impact on how well vertical surfaces are illuminated. The higher the mast, the greater the angle at which light strikes a vertical surface. With large mast heights, the light falls more from top to bottom, which benefits horizontal illuminance but can reduce vertical illuminance.
In practice, this means that a 20-meter or higher mast, while illuminating a large area, is less effective at eye level for recognizing vertical objects than a lower mast with a wider beam pattern. The optimal mast height is therefore always a trade-off between the size of the area, the desired uniformity, and the required vertical illuminance.
An lighting design that only controls at mast height without considering the fixture's beam angle almost always leads to deficiencies in vertical lux. Specialized LED floodlights Adjustable optics offer a solution here, as the light beam can be directed to the areas where vertical illuminance is most needed.
What are the consequences of insufficient vertical illuminance in harbors?
Insufficient vertical illuminance directly leads to safety risks. People, vehicles, and obstacles are poorly recognized at eye level, increasing the likelihood of collisions, falls, and other incidents. Security systems also perform poorly when vertical lighting levels are too low.
The consequences are concrete and multifaceted:
- Increased risk of collisions because crane operators and drivers do not notice vehicles and people at eye level in a timely manner.
- Reduced camera surveillance why license plates and faces remain unrecognizable in security footage.
- Lower labor productivity because employees have more difficulty reading labels, numbers, and signage on containers or vehicles.
- Non-compliance with standards such as EN 12464-2, with possible liability in case of incidents as a result.
- Higher chance of errors during loading and unloading, with cargo or equipment damage as a risk.
How is illuminance measured and controlled on a port site?
A lux meter is used to measure illuminance on a port site. For horizontal measurements, the measuring plane is kept horizontal at working surface height, typically between 0 and 0.85 meters above the ground. For vertical measurements, the sensor is positioned vertically at a fixed height of usually 1.5 meters, directed at the surfaces to be assessed.
A thorough measurement follows a grid of measurement points spread across the site, allowing both average illuminance and uniformity to be assessed. In the design phase, lighting simulations are also used with software such as DIALux or Relux. These programs calculate the expected horizontal and vertical lux in advance based on the chosen luminaires, mast heights, and placement.
Control during installation is just as important as the design itself. Luminaires can decrease in light output over time due to dirt or wear, causing the actual illuminance to drop below normative limits. Periodic measurements and maintenance are therefore an integral part of professional lighting management.
What type of fixture provides the best vertical illuminance in harbors?
Luminaires with an asymmetric or adjustable light beam perform best when it comes to vertical illuminance. They direct light onto vertical surfaces instead of exclusively downwards. High-power LED floodlights with a narrow to medium beam are ideally suited for use on high masts in port terminals.
Besides the bundle angle, the following characteristics are also decisive for performance in a harbor environment:
- High IP rating (min. IP66) for protection against sea air, rain, and dust
- Corrosion-resistant material, preferably stainless steel or specially coated aluminum for salty environments
- Vibration resistance for mounting on cranes or masts that move
- High luminous efficacy per watt for efficient lighting coverage over large areas
- Adjustable optics so that the light beam can still be adjusted after installation
For specific applications such as crane lighting, the choice of fixture is even more critical. Lighting for port cranes sets additional requirements for shock resistance and the ability to illuminate vertical surfaces at a great distance.
Case Study: DFDS Terminal Lighting in Vlaardingen
A striking example of how horizontal and vertical illuminance are tackled together is the project for DFDS Seaways in Vlaardingen. For this terminal operator, a common challenge arose: the existing lighting provided sufficient lux on the roadways but fell short at eye level. Drivers and port employees had difficulty recognizing vehicles and people in the evening hours, and the security cameras produced blurry images due to insufficient vertical illuminance levels.
The technical challenge lay in the combination of a large terrain area, high masts, and the requirement to achieve sufficient lux even at a height of 1.5 meters. The solution involved using LED luminaires with asymmetrical optics, strategically positioned so that the light beams effectively illuminated both the driving surfaces and the vertical surfaces. Consideration was also given to the salty harbor environment: all luminaires received a corrosion-resistant finish and an IP66 rating, minimizing maintenance requirements.
An important lesson from this project: vertical illuminance must be included in simulations during the design phase itself, not corrected afterward. This prevents costly adjustments after installation and ensures that the lighting plan immediately meets the standards. More similar projects can be viewed at DFDS Seaways Vlaardingen project page.
How JEL Products Helps with Lighting Intensity in Ports
JEL Products offers a comprehensive approach to lighting challenges in ports and terminals, systematically incorporating both horizontal and vertical illuminance into the design. It begins with a thorough analysis of the operational requirements, applicable standards, and specific environmental factors of the port area.
What JEL Products specifically offers for port projects:
- Custom lighting design with DIALux simulations, including vertical lux analyses
- Fittings from our own development, tested for sea air, corrosion, and vibrations
- Full scope from engineering to installation, commissioning and maintenance
- Experience with complex port environments, including cranes, quays, and security zones
- ISO 9001 and SCC** certified for quality assurance on every project component
Whether it's a new lighting plan for a terminal or optimizing an existing installation: the approach starts with the initial technical question and continues through to final delivery. Please feel free to contact us via contact page for a no-obligation consultation about your port lighting.
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