Monitoring for Hazards in Bulk Liquids Floating Roof Tanks

Emerson's Per Skogberg


I was alerted to a great new whitepaper about floating roof tank hazards and solutions by our Rosemount radar level measurement and tank gauging systems team including Emerson’s Per Skogberg.

PEMY Consulting whitepaper: Floating Roof Tanks in Petroleum StorageThe whitepaper, by PEMY Consulting‘s Philip E. Myers, describes the types, fault modes, failure causes of storage tank floating roofs and available technologies to address these issues.

Philip has chaired numerous task groups for the American Petroleum Institute, including API 2350—Overfill Protection for Storage Tanks in Petroleum Facilities.

This whitepaper, Floating Roof Tanks in Petroleum Storage opens highlighting the risks associated with these floating roofs. They are:

…one of the most common causes of incidents. Despite this, there is little knowledge about floating roof failures and little focus on floating roof tanks as a safety hazard in the industry.

In the whitepaper abstract, he notes that:

…risk assessment and management sciences together with learnings from previous incidents have reached the point where most serious floating roof incidents are entirely preventable.

The purpose of these floating roofs on hydrocarbon liquids storage tanks is to prevent evaporation and maintain a barrier between the volatile liquid and environment. Other key benefits are:

  1. Reducing emissions, resulting in financial, environmental, and health savings.
  2. Reducing the probability of tank fires and explosions, protecting personnel and capital.
  3. Keeping debris and precipitation out of the product

An:

Electronic Floating Roof Monitoring (EFRM) system can provide early detection of floating roof failure, preventing a variety of serious floating roof failure modes.

These EFRM systems work in part by placing multiple level sensors around the roof:

…that monitors the difference in height between multiple points on a floating roof surface. These points are converted into a distance, and a user specifies the distance parameters that will trigger an alarm or alert on the system computer. This early alert system will prevent the tilt of a floating roof from reaching critical levels before action can be taken to avert an event.

An earlier post here on the blog, Avoiding Dangerous Conditions through Tank Floating Roof Level Monitoring, describes how non-contacting radar and guided wave radar (GWR) level measurement technology can provide these measurements for EFRM systems. By providing continuous level measurement for comparison, tilt conditions can be spotted early and corrective actions taken before more serious situations unfold.

The whitepaper details many types of roof tanks, including fixed roof tank (FRT), external floating tank roof (EFRT), internal floating tank roof (IFRT). If your organization’s production and transportation processes include bulk liquids storage tanks with floating roofs, you’ll want to read the whitepaper to learn more about floating roof components, loss of buoyancy and other failure modes, risk and consequence analysis and more.

I’ll come back to this important subject in the near future to recap a recent Hydrocarbon Processing article by Per, Keep a floating roof on an even keel.

Learn more about the technologies to effectively monitor for roof tilt and other abnormal conditions in the Radar Based Floating Roof Monitoring document on Emerson.com. You can also connect and interact with other level measurement and tank gauging experts in the Level and Tank Gauging groups in the Emerson Exchange 365 community.