PI-04:   Dual Temperature Piping Systems A Serious Hidden Threat Due To An Engineering Design Oversight From More Than 40 Years Ago  From a corrosion perspective, every piping system exhibits certain characteristics in terms of wall loss, the potential for failure, and impact to building operations.  Those characteristics are further influenced by engineering design, materials used, insulation, chemical protection, temperature, and maintenance, among other variables. Pipe Service Life Varies A brass domestic cold water system can last 100 years, as can an extra heavy cast iron storm drain line.  Chill water, hot water, and other closed systems should provide 65 years of service.  Wet fire sprinkler systems can easily last 75 or more years.  Condenser water pipe can provide 60 years of service at the larger pipe; 20 years at the smaller threaded sizes, if provided effective chemical treatment.  Proper maintenance is always an important variable in obtaining long pipe life, along with initial pipe quality. Many piping systems were designed based upon certain assumptions into the future which have proven reasonable and correct.  The use of extra heavy or schedule…

PI-02:   Roof Level Corrosion Avoiding Some Obvious But Surprisingly Common Problems Most building operators see the first indication that a corrosion problem may exist through evidence shown at the roof level.  Some problems may be as minor as a pinhole leak or a failed thread – while others may cause the loss of a major riser.  Problems may be hidden at the pipe’s interior, concealed within the insulation, or as obvious as a trail of rust flowing toward the roof drain. In many instances, suspected wall loss finally becomes obvious by the presence of iron oxide deposits and chip scale in the cooling tower sumps and overhead distribution pans.  Rust and corrosion at the pipe exterior may also be noticed in areas directly exposed to the elements, or more frequently, may exist hidden under the pipe insulation and hard outer metal covering. Dual Corrosion Attack Roof level pipe typically suffers a two front corrosion attack.  If it is drained down partially for winterization in sub freezing climates, higher corrosion rates by as much as 6 times or more above those existing at…

PI-01:   Threaded Pipe Limitations Why You Cannot Use Schedule 40 Threaded Black Pipe in Condenser or Open Water Applications Over the life-span of any building property or plant operation, the replacement, renovation or addition of various piping systems is a frequent occurrence.  Due to the fact that operating pressures of most high rise buildings or process plants rarely exceed 250 PSI, internal pressure does not often factor in the selection of pipe schedule. Today, schedule 40 black pipe is almost automatically chosen for most small diameter piping needs – with little thought given to the physical wall thickness limitations of the pipe itself, or long term service life.  High pressure steam, steam condensate, and other critical services are the exception.  As a result, it is not uncommon to find the premature failure of relatively new condenser or process water installations, as well as examples of properties which have replaced such small diameter piping on a regular basis every 4, 5, or 6 years. Fewer Problems Decades Ago In contrast, piping systems installed decades ago often provide significantly longer service life.  This is in part…

Every piping system has its own separate issues as well as presents a different level of threat to the building owner / manager / operator.  Condenser water is always close to the top of concerns for any chief engineer or property manager due to its critical role, known higher corrosion levels, the potential to cause A/C interruption, as well as the capacity to produce catastrophic water damage.  Failures at threaded condenser water lines have been the cause of some of the most damaging piping failures we are aware. Location is also important.  A condenser water main at the roof presents little to no real threat should a pinhole occur on the low pressure supply header.  Yet, that same diameter pinhole can produce massive damage and downtime where it crosses over a first floor data center under much higher pressure. Storm drains, on the other hand, rate far lesser concerns, as do oil or natural gas lines.  Wet fire standpipe systems very rarely suffer any significant deterioration in contrast to dry and pre-action fire sprinkler systems which have been known to fail in under 5 years.  Their location, typically over critical electronic and computer…