Fixed roof tank
A fixed roof tank is a type of storage tank, used to store liquids, consisting of a cone- or dome-
shaped roof that is permanently affixed to a cylindrical shell. Newer storage tanks are typically
fully welded and designed to be both liquid- and vapor-tight. Older tanks, however, are often
riveted or bolted, and are not vapor tight. A breather valve (pressure-vacuum valve), commonly
installed on many fixed roof tanks, allows the tank to operate at a slight internal pressure or
vacuum. This valve prevents the release of vapors during very small changes in temperature,
barometric pressure, or liquid level.[1] Fixed roof tanks without breather valves will generally be
freely vented;[2] thus the emissions from a fixed roof tank can be non-trivial. Gauge hatches,
sample wells, float gauges, and roof manholes provide accessibility to these tanks, and also act as
potential sources of volatile emissions.[3][4]
Applications
Storage tanks in general, and fixed roof tanks in particular, containing organic liquids can be
found in many industries, including:
petroleum production and refining
petrochemical and chemical manufacturing
bulk storage and transfer operations
other industries consuming organic liquids[2]
Fixed roof tanks are typically used with products that have relatively low volatilities and flash
points.[5] Using a fixed roof tank to store a product with high volatility can lead to product losses
as vapors escape the enclosure.[6]
See also
Storage tank
External floating roof tank
References
1. BNH Gas Tanks. "Fixed Roof Tank" (http://www.fixedrooftank.com/). Retrieved 5 December
2015.
2. South Coast Air Quality Management District. "Supplemental Instructions For Liquid Organic
Storage Tanks" (http://www.aqmd.gov/docs/default-source/planning/annual-emission-reporting/
supplemental-instructions-for-liquid-organic-storage-tanks.pdf?sfvrsn=2) (PDF). Retrieved
5 December 2015.
3. Werner Sölken. "Explore the World of Piping - Introduction to Storage Tanks" (http://www.werm
ac.org/equipment/storage_tanks_vessels_general.html). Retrieved 5 December 2015.
4. USA Environmental Protection Agency. "Alternative Control Techniques Document:Volatile
Organic Liquid Storage in Floating and Fixed Roof Tanks" (http://www3.epa.gov/ozonepollutio
n/SIPToolkit/ctg_act/199401_voc_epa453_r-94-001_liquid_storage_roof_tanks.pdf) (PDF).
Retrieved 5 December 2015.
5. Buckeye Fire Equipment. "Storage Tanks: Fixed or Semi-fixed Systems" (http://buckeyefire.co
m/pdfs/foampdfs/storage/fixed.pdf) (PDF). Retrieved 5 December 2015.
6. ISEC Company. "Fixed Roof Tank" (https://www.youtube.com/watch?v=a_3kOcjLBu4).
Retrieved from "https://en.wikipedia.org/w/index.php?title=Fixed_roof_tank&oldid=777385380"
This page was last edited on 26 April 2017, at 21:28 (UTC).
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