ECS Corrosion Control Blog

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Cold Storage (Freezer) Applications

Posted by Jennifer Combs on Apr 26, 2018 10:00:11 AM

WHAT IS THE BEST WAY TO ELIMINATE ICE PLUGS AND CORROSION?

The use of regenerative air dryers such as the General Air Products Dry Air Pac™ has long been recommended for use by fire protection industry governing standards such as NFPA 13: Standard for the Installation of Sprinkler Systems and Factory Mutual Property Loss Prevention Data Sheet 8-29: Refrigerated Storage.

The intent behind using a regenerative air dryer is to achieve a supervisory gas dew point that is at least 20⁰F below the lowest freezer temperature that is being served by the supervisory gas source. By achieving this target dew point, science would suggest that ice plugs would not form within the fire sprinkler system piping. However, years of empirical data prove the opposite.

Since 2008 Engineered Corrosion Solutions has been pioneering the use of nitrogen generators and oxygen removal vents to purge dry and preaction systems of oxygen to control corrosion and prevent system leaks. During that time ECS has recognized that while oxygen corrosion will not occur in freezing environments (there is no liquid water in which the oxygen molecules can dissolve) the -70⁰F dew point of 98% nitrogen gas is extremely effective in preventing frost buildup and ice plugs in fire sprinkler systems serving freezers.

Other advantages of using nitrogen generators over regenerative air dryers

  • Many more systems can be served by a single nitrogen generator than a single regenerative air dryer
  • Actual operational effectiveness (no ice plugs)
  • Significantly less maintenance cost and reduced energy usage

ECS has worked closely with several cold storage facility operators over the past three (3) years to prove that a nitrogen generator is a superior source of supervisory gas for dry and preaction systems that are installed in freezer applications:

Nitrogen Generator Outcome versus Dry Air Pac™ (28 months)
Description Problem Solution Result
Forty-eight (48) dry fire sprinkler systems protecting a 1MM+ cold storage facility being supplied with supervisory gas from eight (8) General Air Products Dry Air Pacs. The fire protection systems routinely undergo annual insurance inspections. Frost and ice plugs were consistently being found during annual inspections. Facility maintenance personnel found that maintenance of the Dry Air Pacs to be cumbersome and costly. Four (4) of the Dry Air Pacs were replaced by a single Engineered Corrosion Solutions Nitrogen Generator (half of the systems were switched to nitrogen as a supervisory gas and the other half remained on Dry Air Pacs) Zero ice or frost accumulation was found in the systems being served by nitrogen during the subsequent two (2) annual inspections. Frost and ice plugs continued to be found in the systems being served by the Dry Air Pacs. The remaining Dry Air Pacs are slated for replacement.

 

Nitrogen Generator Outcome versus Dry Air Pac™ (7 months)
Description Problem Solution Result
One (1) dry fire sprinkler system protecting a -10⁰F cold storage facility being supplied with supervisory gas from a General Air Products Dry Air Pac™ which was sourcing compressor air from the freezer. The fire protection system routinely undergoes quarterly inspections. Frost and ice plugs were consistently being found in the air supply lines and supply main during quarterly inspections. The Dry Air Pac™ was replaced by an Engineered Corrosion Solutions Nitrogen Generator. Zero ice or frost accumulation was found in the nitrogen line and supply main during the subsequent two (2) quarterly inspections.

 

Read More: Controlling Ice Plugs and Corrosion in Fire Sprinkler Systems Protecting Cold Storage (Freezer) Applications

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Jennifer Combs

Written by Jennifer Combs

Marketing Manager