Geodesic Domes for Storing Coal

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Storage Domes for
	Ring stockpiles
	Conical piles
	Longitudinal
	Free form piles
	Featured cases:
		Hazardous bulk materials

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Geodesic Domes for Storing Coal, Urea and
Other Combustible or Corrosive Bulk Materials


		4 Coal Storage Domes, 126m diameter, Taiwan

Coal, wood chips, urea, sulfur and other materials present special special storage challenges: they may attack the structure's metallic components or, because of their combustibility, present a risk of explosion. Geometrica offers options that help in controlling the hazards presented by these material, including corrosion resistant materials, tubular structural members, and the possibility of placing the dome's cladding internal to the structure.


	122m X 54m Urea Storage Dome with Internal Cladding, Port of Veracruz, Mexico

For example, in the case of coal, the National Fire Protection Association, in its publications NFPA 850 and 120, identifies the hazards associated with storage and handling of this material, and gives recommendations for protection against these hazards. NFPA recommends that storage structures be made of non-combustible materials, and that they are designed to minimize the surface area on which dust can settle, including using structural sections that minimize or eliminate any ledges on which dust can accumulate, or the desirable installation of the cladding underneath a building’s structural elements.

The recommendation requires an explanation: First, coal and other combustible materials are susceptible to spontaneous combustion due to heating during natural oxidation of new particle surfaces. Second, combustible dust is an explosion hazard. If a dust cloud is generated inside an enclosed space, and an ignition source is present, an explosion can ensue. Dust clouds may generate wherever loose dust accumulates, such as on structural ledges, if there is a nearby impact or vibration due to wind, earthquake, or even maintenance operations. Coal, for example, has a propensity to heat spontaneously, and ignition sources are almost impossible to eliminate in coal storage and handling. Any enclosed area where loose dust accumulates is at great risk. Further, even a small conflagration can result in a catastrophic "secondary" explosion if the small event releases a much larger dust cloud.

The standards also recommend several other items, including:

Storage piles should be worked to prevent dead pockets of material, a potential source of spontaneous heating. In the case of coal, its storage should be for as short duration as possible. Coal piles should not be located above sources of heat such as, steam lines or manholes. Coal should be piled in layers and compacted to reduce air within the pile.
Coal should be kept as dry as possible (sprinklers are not recommended).
Combustible material piles should be constantly monitored for hot spots using temperature detection systems.
When a hot spot occurs a management strategy should be in place to remove the ignited material. Access should be provided for firefighting at sufficient intervals on the perimeter of an enclosure.
The structure should have minimal surfaces for dust to accumulate inside the dome. For all surfaces where dust may accumulate, adequate dust removal systems should be provided.
Ignition sources should be kept to an absolute minimum. Static electricity hazards should be minimized by the appropriate grounding of all equipment. All machinery and electrical equipment inside the dome should be approved for use in hazardous locations and provided with spark-proof motors.
Provisions should be made to turn off all electrical circuits without the need for personnel to enter dust-producing locations.
A sufficient ventilation system should be provided to reduce the chance of methane (and, in case of fire, smoke) build up and for explosion venting requirements. Ventilation should be provided at the apex to take advantage of the chimney effect. The structure should also be vented at the perimeter to reduce the damage to the structure due to blast overpressures.

Geometrica offers tubular structures and internal cladding solutions to meet all the relevant recommendations. A dome protects the pile from rain and wind (which would otherwise foster spontaneous combustion in open-air piles, and cause air and runoff pollution). Tubular structural elements and/or internal cladding prevent dust accumulation on the structure.

With its tubular structural system, Geometrica has built many domes for coal, urea and other combustible and corrosive materials, in every stockpile shape (ring, conical, longitudinal and free-form). And Geometrica's internal cladding is available with special coatings for enclosing highly corrosive materials, or may even be made of fiberglass or plastics.