Research

The engineers at fpsCMI have completed research and published white papers on the following fire protection system corrosion topics.  Please click on the link provided at the end of each paragraph to view the white paper

NEW!  White Paper : Six Reasons Why Chemical Corrosion Inhibitors Should NOT be Used in Water Based Fire Sprinkler Systems:

As the installed water based fire sprinklers in the US continue to age, many systems begin to experience pinhole leaks caused by corrosion on the internal surfaces of the piping. The current state‐of‐the‐art research regarding corrosion in fire sprinkler systems suggests that the primary cause for these corrosion related failures is dissolved oxygen in the water. Although microbiologically influenced corrosion (MIC) can be a contributing factor, there is strong empirical evidence gathered by two independent firms who have investigated actual fire sprinkler pipe failures which indicates that MIC accounts for less than 15% of the corrosion related failures. Oxygen corrosion accounts for the vast majority of corrosion related pipe failures. The standard list of chemical corrosion inhibitors that provide excellent corrosion control in fresh water flowing environments have a much more difficult task in controlling corrosion in water based fire sprinkler systems. The following discussion proposes six reasons to consider before putting chemical corrosion inhibitors into a fire sprinkler system. Click to view White Paper

 
UPDATED!  White Paper : Six Reasons Why Galvanized Steel Piping Should NOT be Used in Dry and Preaction Fire Sprinkler Systems:

Galvanized steel pipe was originally specified as an upgrade to traditional black steel to provide more resistance to corrosion in dry and preaction fire sprinkler systems. In theory this approach makes sense because galvanized steel pipe is internally and externally coated with zinc which should provide resistance to atmospheric corrosion on the external surfaces and resistance to internal corrosion when used in “dry pipe” fire sprinkler applications. Unfortunately, dry pipe fire sprinkler systems are rarely completely dry. Under persistently moist, oxygenated conditions the zinc coating on the interior walls of the piping corrodes quite aggressively and failures can occur in as few as 12 months after installation. Discharge water from galvanized sprinkler systems that have been actively corroding may also contain high levels of zinc which has been classified as a toxic heavy metal contaminant in waste water effluent streams. This paper explores and discusses six primary reasons that galvanized steel piping should not be used in fire sprinkler applications. Click to view White Paper

White Paper : Controlling Corrosion in Wet Pipe Fire Sprinkler Systems Using Chemical Corrosion Inhibitors:

The use of chemical additives to control oxygen corrosion in wet pipe fire sprinkler systems presents a variety of very significant challenges.  The standard list of alkyl amines and quaternary amines that provide excellent corrosion control in fresh water flowing environments have a much more difficult task in controlling corrosion in what amounts to batch treating a long, narrow, stagnant, solids filled pool of water with lots of “dead ends” that periodically and regularly receives a fresh supply of oxygen.  The introduction of any chemical additive may require modification of the back flow prevention devices on the fire sprinkler system.  There are also significant compatibility considerations for chemical additives and fire sprinkler system elastomers that are found in gaskets, valves and other system components.  This paper explores all of the complicating issues associated with using chemical corrosion inhibitors in wet pipe fire sprinkler systems. Click to view White Paper

White Paper : Using Galvanized Steel Piping in Dry and Preaction Fire
Protection Systems:

The use of galvanized piping has been proposed as a remedy for controlling corrosion in dry and preaction fire protection systems.  Although there are several different galvanization methods, the end result is that alloyed layers of zinc are applied to the base metal which is mild steel.  Dry and preaction fire sprinkler systems always contain some amount of trapped water.  In the persistently moist, oxygenated environment that exists inside the piping, zinc DOES NOT provide adequate protection to prevent premature failure due to corrosive attack. Click to view White Paper

White Paper : Using Nitrogen Gas in Dry and Preaction Fire Sprinkler Systems:

In order to prevent the corrosive effects of oxygen in dry and preaction fire protection systems, nitrogen can be used as the pressurizing gas in place of compressed air.  When nitrogen is added as the pressurizing gas to “dry pipe” systems containing air at atmospheric pressure, the concentration of nitrogen gradually increases as the pressure increases.  Compressed air contains 78% nitrogen, 21% oxygen and 1% other trace gases.  However, in order to achieve corrosion control, the fire sprinkler system piping must be vented during nitrogen addition to remove the oxygen that was initially present when air filled the pipes.   The objective is to ultimately achieve an atmosphere in the pipe that is 95%+ nitrogen gas. Click to view White Paper

White Paper : Using Nitrogen Gas to Remove Corrosive Gases in Fire Sprinkler Water:

By continuing to increase the percentage of nitrogen in the fire sprinkler system, oxygen can actually be stripped out of the water. When this is accomplished, the oxygen is no longer available to corrode the metal surfaces of the pipe. This phenomenon is at the heart of the process of using nitrogen gas to control corrosion in fire sprinkler systems. This approach to corrosion control works in both residual amounts of water that are trapped in dry pipe fire sprinkler systems and with water contained in wet pipe fire sprinkler systems. Click to view White Paper

White Paper : Atmospheric Corrosion of Malleable Cast Iron Fittings Used in Wet Fire Sprinkler Systems:

When wet fire sprinkler systems are put into service the pipes are filled with water and pressurized to allow for instant delivery of water from the sprinklers in the event of a fire.  In many installations, like warehouses and garages, fire sprinkler piping is exposed to unconditioned ambient air and is subject to the normal temperature fluctuations that occur during seasonal weather changes.  Whenever the temperature of the ambient air is warmer than the temperature of the water in the fire sprinkler piping, there is a chance that water can condense on the outside surface of the pipe.  Malleable cast iron fittings that are typically used during construction of wet fire sprinkler system have no protective coating and the iron in the fittings is readily available to react with any water that condenses on the surface of the fitting. Click to view White Paper

White Paper : MIC is NOT the Primary Cause of Corrosion in Fire Sprinkler Systems:

The simple fact is that the primary cause of internal corrosion (metal loss) in fire sprinkler systems is oxygen attack of the iron and zinc (in the case of galvanized pipe) that are used to fabricate fire sprinkler system piping. While it is true that microbiologically influenced corrosion (MIC) is often a contributing factor to the overall corrosion picture, it is not the primary cause of the internal corrosion.  Moreover, the solids that are produced by the action of oxygen on the metal piping actually produce conditions that favor the proliferation of bacteria in the system. Click to view White Paper

White Paper : Mission Critical Facilities - Is the Use of Galvanized Pipe an Effective Corrosion Control Strategy in Double Interlock Preaction Fire Protection Systems?

There is now a significant body of evidence that suggests that the use of galvanized steel pipe in dry and preaction fire sprinkler systems may expose mission critical facility owners to the risk of premature system failure due to internal corrosion. Conditions that typically exist within dry and preaction fire sprinkler system piping create an environment in which zinc coated mild steel will corrode, sometimes quite aggressively. In the case of mission critical facilities, the risks of premature failure are more pronounced than they might otherwise be because of the sensitivity and costs of the systems that are being protected. A water leak simply cannot be tolerated. Click to view White Paper

White Paper : Controlling Corrosion in Fire Protection System Protecting Cultural Resources:

Providing fire protection systems for cultural resources (museums, libraries and antiquities) poses several interesting dilemmas when it comes to sprinkler design considerations.  Although it seems quite prudent to install fire sprinklers to mitigate the risk that fire might damage or destroy the cultural resources, there are real and quantifiable risks associated with the act of placing water filled piping above these invaluable collections or invaluable facilities.  Accidental water discharge and leaking pipes can pose intolerable risks.   Taking steps to mitigate risks can only be done with a complete understanding of the root causes of the corrosion and the proper means for prevention.  This paper examines all of the issues associated with managing corrosion in a cultural resource setting. Click to view White Paper