Materials Performance

NOV 2014

Materials Performance is the world's most widely circulated magazine dedicated to corrosion prevention and control. MP provides information about the latest corrosion control technologies and practical applications for every industry and environment.

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Page 21 of 92

19 NACE INTERNATIONAL: VOL. 53, NO. 11 MATERIALS PERFORMANCE NOVEMBER 2014 Information on corrosion control and prevention coated structures ranging from 2.5 in wide up to 6 ft (1.8 m) in diameter. Brasher says that in addition to DOT traff ic structures, the EPC can be used for corrosion protection on prestressed con- crete cabling and suspension bridge cabling, rebar reinforcement systems, electric utility transmission and distribu- tion infrastructure, and storage tanks. Contact Jon Brasher, Ovanteā€”e-mail: References 1 ASTM B117-11, "Standard Practice for Oper- ating Salt Spray (Fog) Apparatus" (West Con- shohocken, PA: ASTM International). 2 ASTM D6677-07, "Standard Test Method for Evaluating Adhesion by Knife" (West Con- shohocken, PA: ASTM). 3 ASTM G154-12A, " Standard Practice for Operating Fluorescent Light Apparatus for UV E xposure of Nonm etallic Mat erial s" (West Conshohocken, PA: ASTM). 4 ASTM G151-10, "Standard Practice for Ex- posing Nonmetallic Materials in Accelerated Test Devices that Use L aborator y Light Sources" (West Conshohocken, PA: ASTM). Bibliography Brash er, J.H., et al . " Em erging Technolog y : Report on Development of an Enhanced Plastisol Coating System for Atmospheric, Transitional , and Soil and/or Water Im- mersed Applications on Steel Substrates." CORROSION 2014, paper no. 3906. Houston, TX: NACE International, 2014. Nitrogen generator inhibits corrosion within fre protection systems W hen dry and pre-action f ire protec- tion systems experience internal corrosion in their piping network, several problems can ensue for building owners and operators. The build-up of corrosion product deposits can reduce the eff i- ciency of the sprink ler system and water leaks from pinholes can cause property damage. According to NACE Interna- tional member Ockert J. Van Der Schijff, senior manager with engineering and sci- entif ic consulting f irm Exponent, Inc. (Natick, Massachusetts), the cost to re- pair a single pinhole leak in a sprink ler pipe is usually in excess of $1,200 per event. Even more alarming is that often times before the pinhole leak has oc- curred, tuberculation, scaling, and other MP submissions and leads for department. Contact MP Associate Editor Fax: E-mail: Continued on page 20 corrosion products have accumulated within the sprink ler piping, which cause obstructions that will slow down the water f low in the event of a f ire, or poten- tially plug a sprink ler head and render it completely inoperable. Dry and pre-action sprink ler systems are not charged with water, but use com- pressed supervisory gas instead, says Scott Bodemann, senior vice president of sales & marketing for South-Tek Systems, LLC (Wilmington, North Carolina). The pressure of the supervisory gas in dry sys- tems balances a valve in the sprink ler sys- tem with water line pressure until a pres- sure drop occurs when a sprink ler head is activated. Water is then introduced into the piping to suppress the f ire. Pre-action systems essentially utilize the same prin- cipal, but require activation of an addi- tional signal such as a temperature sen- sor or smoke alarm before the valve opens and water is introduced into the piping. Ty pically, dry and pre-action f ire protec- tion systems use compressed air as the supervisory gas to keep the piping system pressurized. However, compressed air from the atmosphere contains both mois- ture and oxygen, which can cause corro- sion of the steel piping. A proven solution to mitigate corro- sion in sprink ler systems is the use of compressed nitrogen instead of com- pressed air as the supervisory gas. The nitrogen displaces the oxygen within the sprink ler piping and effectively removes a signif icant contributor to corrosion. To meet the need for this continuous supply of compressed nitrogen gas, South-Tek has developed a corrosion inhibiting nitrogen generating system, the N 2 -Blast, that provides inert nitrogen specif ically for f ire protection systems. Many new dry and pre-action f ire pro- tection systems are constructed of hot- dip galvanized steel, although the use of black steel pipe is on the rise. In their paper that reports the preliminary f ind- ings of an exposure test experiment on piping materials currently used for dry and pre-action sprink ler installations, 1

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