Explosion-Proof Floodlight for Pipe Racks Shadow and Beam Distribution Analysis

The pipe rack structures in offshore installations, maritime terminal, and petrochemical plants carry process piping, cable tray, and steel structure through several stories. This results in shadows in maintenance walkways, valve stations, and inspection areas. In this regard, the lighting system design becomes a crucial part of the electrical system design of the installation.

The selection of an appropriate explosion-proof floodlight for the pipeline rack structure is not only dependent on the fixture wattage and luminous flux. Issues like beam orientation, mounting, structure obstruction, and lighting distribution become the deciding factor of whether the critical areas are well-lit or not.

Identification of the Lighting Problems in an Industrial Pipe Rack

Structural Shadows Caused by Pipes and Steel Beams

Large pipes, cross beams and other structural supports might create shadows in the area, causing darker areas in the shadow of the obstacle. This point is especially relevant in the case of multi-level pipe racks where the lighting mounted on the top level of the pipeline would not light the lower levels.

Obstructed Visibility at Valves and Maintenance Points

Valves, flanges and other inspection points usually are situated in between the pipelines or in the vicinity of the structural elements. Lighting of the walkways alone might not suffice for the inspections and maintenance activities. The horizontal and vertical illuminance levels should be considered by the engineers.

Difficult Offshore and Marine Operating Conditions

Water, salt, vibration, and temperature fluctuation would impact the lighting fixtures due to the presence of offshore facilities and marine terminals. The selection of the lighting fixtures would require consideration of the following: environmental conditions, hazardous location, installation requirement, and maintenance requirement.

For this exercise, it could be assumed that there is a pipe rack measuring 30 meters long, 6 meters wide, and 8 meters high and having three levels of pipes. This could be assumed as there are no real figures provided by the project and the values given are only assumed values. There are pipe heights, beam location, cable tray size, and other requirements.

Selection of Explosion-Proof Flood lights Based on Photometrics Data

The selection of explosion-proof flood lights to be used in pipe racks requires evaluating the light coverage in respect of the height, barriers and area where work will be performed. Only knowing the wattage and lumens does not provide an idea whether there is enough light coverage.

IES/LDT Data Comparison

The data about IES or LDT about specific lighting fixture should have information about the beam spread, intensity and direction of light. While narrow beam can be applied to illuminate walkways, a wide beam can be used to cover the area between the pipes and metal structures.

Conditions of Installation Considerations

What should be taken into account are the height of installation of fixture, its aiming angle, location of walkways, valves and inspection points. Such selected beam should illuminate the areas without casting any shadows of pipes, crossbeams and cable trays.

Verification of Coverage with the Help of Lighting Simulation

Upload the file to the lighting simulation application like DIALux evo or Relux and build up the model of future pipe rack configuration. Study the illuminance and uniformity on the work area and make changes in the position of lighting fixtures.

For instance, CFD13 LED Explosion-proof Flood Light and CFT6 Explosion-proof Flood Light can be analyzed using the approach described above.

Beam Distribution and Structural Shadows Analysis

Pipe Rack Light Layout requires analysis both in terms of plan and elevation. In Plan View, one sees the placement of light fixtures and the horizontal spread of the beam. In Elevation View, one observes the blockage of light and relationship between the beam and different levels of pipes.

For example, a Floodlight placed over the top of the upper pipe will illuminate the structure itself but cast shadow below the crossbeam. Just as such, nearby pipes may block light to the lower maintenance level.

A good shadow analysis would include:

• Structures such as steel beams and pipes that block the direct light.
• Cable trays and equipment that create local shadows.
• Operational areas of valves needing more visibility.
• Structures that have the light fixture aiming too much of light on the pipe and not the work area.

In case there are some zones where there is a need for substantial evaluation of shadows, the engineers can try out different locations or angles of positioning of the lights or other light sources. All the changes should be made keeping in mind safety aspects such as accessibility, clearance, cabling, and mounting.

For marine/offshore applications, the site survey should also evaluate if the selected site is feasible for future inspection and maintenance work.

Illuminate Distribution and Uniformity Evaluation

Photometric simulation is helpful to determine if the lighting design provides enough light for work areas.

Engineers can create a model of a pipe rack using programs such as DIALux evo or Relux and compute illuminance depending on the photometric characteristics of selected luminaires.

It will be able to define the corresponding working planes. Walkways will be computed on the horizontal plane, and valve faces on the vertical plane.

Each area has to be described by:

• Average illuminance, (E_{\mathrm{avg}}), in lux.
• Minimum illuminance, (E_{\min}), in lux.
• Maximum illuminance, where appropriate.
• Uniformity ratio, (E_{\min}/E_{\mathrm{avg}}).
• Calculation plane, grid parameters, and maintenance factor.

Areas with darkness may be found using a false color diagram of illuminance; these areas cannot be found using an average illuminance value alone. For instance, a properly lit walkway does not guarantee enough light in a valve that is located behind the pipeline.

Values of illuminance and uniformity have to be calculated according to project requirements. Only numerical values that are the result of the correct simulation with the corresponding geometry and photometry can be provided.

Ensure Explosion Protection and Compatibility with the Marine Environment

It is important to ensure that the floodlight you have chosen is rated for explosion protection compatible with the area of installation. Some of the things to take into consideration are gas group, temperature class, equipment protection level, and ambient temperature rating. The ratings should vary with respect to the product line.

If the floodlights have to be installed in a marine and offshore environment, then the materials that have been used must have resistance to salt water, vibration, humid environment, and corrosive chemical exposure. It should be remembered that IP66 rating does not automatically mean that the light is explosion-proof.

What Should be Included in Pipe Racks Lighting Assessment?

Good engineering assessment must yield three items:

• Flood light positioning diagram: Positioning of the luminaires, height at which the luminaires are mounted, spacing of the luminaires, directionality and illuminated working area.
• Study of flood light beam and shadows: Blocking objects like pipes and any other structure, shadow formation and any other areas where flood lights could be installed.
• Report on illumination simulation: Average and minimum illumination, illumination uniformity, assumptions used for the calculations, false color diagrams.

Ship yards, Offshore EPC Companies and Petrochemical Construction will consider beam characteristics, structure blocking and hazardous areas while selecting explosion proof flood light for pipe racks.

Yushuo Lighting offers explosion proof flood light for industrial and marine applications. Contact us for your needs.