Storage tanks or tank farms are an indispensable component of facilities such as chemical processing plants, petrochemical factories, distilleries and similar work environments. These storage tanks hold materials which although indispensable in the manufacturing process, generally are hazardous in nature such as hazardous liquids and compressed gases.
Tank farms can be of varied sizes having different capacities for storing liquids or gases. In most cases the materials stored in them are inflammable. A fire, caused by any reason such as lightning, is difficult to control, once started. It not only puts the material inside the tank in danger but also risks the lives of the people who work in the same environment. The amount of pollution generated through such a fire as well as the economic damage can be incredibly high.
Hence, immense attention needs to be provided to several aspects of storage tanks.
Building a tank farm
By its nature, a tank farm stores heavy items. Hence, it should be built on a good load-bearing ground or the foundation must be piled properly. Health and Safety Executive, UK recommends selecting the location of a tank farm carefully. It should be placed at the boundary of any facility, away from on-site buildings and any sources which may have a potential for igniting.
The Health and Safety Executive also recommends building a tank either above or below the ground. Building a tank below the ground is usually disfavoured since monitoring a leakage becomes difficult. Hence, most storage facilities have tanks built above the ground.
The lighting of tank farms
Since the materials contained in storage tanks are inflammable, special emphasis on safety is essential. This involves monitoring them round the clock.
While tank farms can be built away from other facilities of the industrial unit to ensure minimal damage in case of any mishap, proper lighting of the farms is of crucial importance. This helps in effective monitoring of the tanks for potential leakage as well as helps in regular maintenance and cleaning of the tanks.
However, wherever there is lighting, there is a scope for ignition. This is why lighting needs extra attention.
Here are the top three this that needs consideration:
1. The number of light levels required. This depends on the height, width and length of the structure.
2. The arrangement of light units at each level and the number of lights to be installed. This should be done to ensure that every angle of the tank is visible in azimuth.
3. The installation should provide a complete understanding of the entire structure of the buildings.
To adapt to the inherently hazardous nature of tanks, all lighting should be LED. LED lighting not only offers safety, but they are also low maintenance and contribute to CO2 reduction. A variety of LED lighting is available in the market today to cater to different kinds of tank farm lighting needs. Their environmentally friendly nature has contributed to their popularity for illuminating hazardous areas.
Lighting specifications for tank farms
No matter which industry storage tanks are used for, their lighting requirements remain more or less the same. Here are a few rules of thumb that one can follow for designing a lighting system for a tank farm:
1. Low-intensity lights are ideal for structures with a height of less than or equal to 45 metres for night-time use. Medium to high-intensity lights should be used only if the low intensity is found to be inadequate.
2. A, B or C Type medium intensity light should be used for lighting structures between 45 metres to 150 metres high. Type A and C can be used as a stand-alone structure, while Type B can be used in combination with LIOL-B.
3. High-intensity type A is ideal for objects more than 150 metres high. An aeronautical study has indicated that not just at night time, such lights are essential for the recognition of objects during the day as well.
Here is more specific guidance on lighting for tank farms based on the lux levels of tank farms.
|Application||Typical Use||Horizontal Illuminance Eave (LUX)||Horizontal Illuminance Emin/Eave||Ra||Glare||Notes|
|Processing Areas||–||>300||> 0.5||> 70||> 50||Indoor|
|High-risk Filling Areas||–||>300/50*||> 0.5||> 70||> 50||Outdoor*|
|Low-risk Filling Areas||–||>100||> 0.5||> 70||> 50||–|
|Walkways||Transit||>100/50*||> 0.5||> 70||> 50||Outdoor*|
|Stairs & Landings||Transit||>100/50*||> 0.5||> 70||> 50||Outdoor*|
|Sludge Chambers||–||>300||> 0.5||> 70||> 50||–|
|Emergency Lighting||High risk||15% of normal illuminance|
Types of lighting for tank farms
Tank farms usually require both portable and fixed explosion light fittings suitable for Zone 0, Zone 1 and Zone 2 areas. AJV Technical Equipment has a wide portfolio of tank farm lighting solutions which include:
- SPARTAN Linear Zone 1 lighting – 2 feet and 4 feet
- SPARTAN Linear Zone 2 lighting
- Pendant light fitting
- High power floodlight for Zone 1
- SPARTAN Linear Zone 1 emergency lighting
Our portable Zone 0, Zone 1 and Zone 2 lights are suitable for tank cleaning and maintenance while pendant lights, food lights and linear fixtures are ideal for external lighting. All our light fittings for tank farms are certified to be used in an explosive environment.
Please keep in mind that the lighting specifications mentioned in this article are only a general guidance matrix. Every facility will be unique and will have its specific requirement. It is important to design the lighting system based on the definite requirement of a facility.