Piping Changes – Past to Present

The below three photographs dramatically illustrate our continuing concerns and warnings to the industry over the deteriorating quality of not only steel pipe, but to all American piping products.

One photo represents a 12 in. steel HVAC condenser water riser in operation for 27 years and chemically treated to control corrosion until a failure removed it from service.  The second from the inside of a 54 year old steel domestic water storage tank, coated to protect it from corrosion.  And the third from a steel side wall plate from the RMS Titanic, having rested on the bottom of the Atlantic ocean for over 108 years.

Indeed, without our photo credit and the rivets at the Titanic hull to give away the answer,
how many readers might have guessed entirely wrong?

While there are significant differences which make the above comparison somewhat invalid, most notably that the Titanic’s steel was made in Scotland, and that far less oxygen exists 27,500 ft. at the bottom of the cold Atlantic Ocean, the fact remains that many changes have occurred to the steel industry which have negatively impacted its quality and most importantly – its service life.

Over the past 25+ years, CorrView International, LLC has performed hundreds of ultrasonic investigations of either very old pipe installed in the early 1900’s, or at properties where a combination of old and new pipe exist.  That work offers a remarkable demonstration of how low cost foreign imports, a more competitive marketplace, recycled products, and excessive environmental controls and regulations over US steel manufacture have reduced the quality and corrosion resistance of today’s steel piping products.  With now having performed nearly 1,050 investigations addressing 2,550 piping systems with over 3 million wall thickness measurements taken, we have established what most would recognize as an authoritative understanding of this subject.

Combined with less tolerant engineering practices, thinner pipe materials, cost cutting, less effective corrosion inhibitors, as well as other factors, most new piping installations can be expected to provide significantly less service life than those built many decades earlier.  While today most property owners and operators are still shocked to learn that their 90 year old piping systems have reached the end of their service life and require replacement, hearing the same news about a 7 year old domestic water system at a new hi-rise luxury residence is beyond devastating.

Some of the issues impacting the dramatically lower service life of all piping systems are:

• Lower Quality Of Virtually All New Pipe
  

First and foremost is the unquestionable superiority in quality and corrosion resistance of pre World War II steel pipe to anything manufactured today – whether foreign or domestic.  Our ultrasonic testing of steam systems from 1911 have shown a minimal loss of only perhaps 20% from the original wall thickness. 

Testing of some galvanized steel domestic water risers from 1935 have documented little if any wall loss.  In one of our oldest investigations of a galvanized steel domestic cold water riser installed in 1896 at a downtown New York City property, only in 2014 did the pipe finally show the need for replacement!  We have identified unpainted and unprotected outdoor condenser water pipe installed in 1941 to still show its original ASTM stamp – even after being subject to decades of weathering and constant cooling tower overspray.  We have documented cut and abandoned roof level pipe showing no wall loss after 80+ years of environmental impact.

Today, the quality of carbon steel, galvanized steel, copper, cast iron, ductile iron, and even stainless steel pipe have all declined significantly; manifest most obviously in much higher corrosion losses and greatly reduced service life.  New carbon steel condenser water pipe having documented 20+ MPY corrosion levels is no longer an anomaly, nor even copper pipe at 1.8 MPY – 10 times higher than normal for domestic water service.

Shown at left, a pinhole through 2 in. schedule 40 galvanized steel domestic water pipe in a little over just 1 year.  That’s a loss of 0.154 in. of pipe wall, or a seemingly impossible corrosion rate of 154 MPY!  This pipe section, was installed in order to repair a section of original galvanized steel pipe which had recently failed after 50 years of service.  Elsewhere, we have documented the failure of entire no-hub cast iron waste piping systems in 15 years.  We have even documented 304 stainless steel schedule 40 pipe used to avoid frequent replacement of steam condensate lines to develop pinholes after just 6 years.

Indeed, the failure of entire piping systems within 10 years is no longer any surprise to us, although always a shock to the property owners and to those responsible for maintaining building operations.

• Physically Undersized Pipe

It is not uncommon to find high wall thickness at older properties from the 1970s still exceeding new ASTM specifications.  This is due to older pipe having been manufactured generally at or above the wall thickness specified by ASTM.  Where low corrosion exists, such as for steam or many closed systems, it is still possible to find older pipe exceeding factory ASTM specifications after 40+ years of service.

In fact, carbon steel pipe can be manufactured having a wall thickness +/- 12.5% of its specified value and still be considered acceptable for installation – a remarkably high 25% tolerance established in the early 1900s and yet still the standard 100+ years later.

New pipe manufactured to its true ASTM specification is exceptionally rare today.  These days, most pipe is produced substantially undersized due to what we believe are closer production tolerances enabling manufacturers to produce a lighter but still approved product close to the minimum limits of the ASTM code.  The issue is common throughout manufacturers foreign and domestic, common for every piping material used in building construction, and common for all pipe sizes and schedules.

Extensive testing of new and uninstalled steel pipe has consistently found undersized material near minimum standards and statistically beyond any possibility of being a random event.  With a permissible tolerance of + / – 12.5%, most new pipe we measure is close to the lower boundary of this limit, and very rarely at true ASTM factory specification or above.  An FM or UL approval rating or ASTM stamp does not mean that the pipe wall is at the ASTM thickness specification stenciled on every section of pipe, as most professional engineers, and building owners and operators reasonably assume.

While most noticeable for carbon steel pipe, showing this 8 in. schedule 40 pipe 13.7% undersized and beyond its permissable ASTM limit at left, we have well documented copper, cast iron no-hub, galvanized steel, and even stainless steel pipe having also been manufactured significantly undersized.

A note of interest.  Following one investigation where we identified 3 year old no-hub pipe substantially below published wall thickness specifications, the client called the piping manufacturer.  Their response, “The pipe is fine and there is no corrosion problem; our pipe is produced within its accepted tolerance to the low wall thickness your consultant measured.”

• Thinner Piping Materials

For older pre-1970’s building properties or plant operations, it is unlikely to find anything but schedule 80 or extra heavy black pipe in use for cooling water, steam, or steam condensate service.  However, today, schedule 40 is the standard specified; schedule 20 the occasional finding for condenser water service.  Contrasting any larger diameter standard grade pipe of 0.375 in., extra heavy pipe offers a substantially greater 0.500 in. of wall thickness.

For the past 30 years, the direction of all piping systems is toward the use of thinner materials.  This is especially an issue for fire protection systems, where thin wall schedule 10 pipe is now the industry standard; replacing schedule 40 before it and schedule 80 before that.  Now ultra thin wall schedule 7 pipe is widely used; even approved for threading at fire service applications!  Of course, wall thickness is not shown in the cut sheet literature – just its larger inside diameter and the fact that its superior flow characteristics will carry more water.  Mathematical manipulations. such as “Corrosion Factor,” which has nothing to do with corrosion whatsoever, have even been created to promote and justify the use of thin wall pipe for fire protection systems.

High pressure steam and steam condensate, once almost exclusively installed using extra heavy pipe, are now installed using mostly standard or schedule 40 product.  Thin wall Type M copper is replacing Type L where heavy Type K was once the standard.  No-hub cast iron pipe now having a wall thickness of 0.190 in. has replaced former cast iron bell and spigot pipe having a wall thickness of 0.430 in.  Rubber couplings have replaced sealed joints.  A comparison between old and newer 4 in. cast iron pipe is shown at left.

• Foreign Products

Pipe manufactured outside of the United States is unquestionably of lesser quality.  Claimed and even stamped to meet ASTM standards and in fact verified as such by metallurgical labs where failures have occurred and lawsuits have forced the issue, the fact remains that a higher level of advanced failure exists for the 30 or more foreign pipe products we have investigated.  For whatever reasons may exist and political correctness aside, overall quality is lower, ERW seams are weaker or incomplete, the galvanizing finish is extremely poor, and corrosion resistance is lower – all of which contribute to greater problems and much lower service life.

Sadly, most USA manufactured pipe is quickly declining in quality to meet that of their foreign competitors.  While significant quality differences once existed back in the 1980s when foreign imports appeared in significant quantity, those differences have all but vanished, and buying American is sadly no longer a guarantee of a better piping product.  More information on this subject is available Here.

• Joining Methods

While the proven longevity of grooved clamped piping is impressive, it still does not have the physical strength and reliability of welded pipe.  Two potential sources of failure at the gasket and at the end gap between pipes still remain, and only increase with system age.  When failure occurs, and especially for a 12 in. main condenser water line, it can reach the highest severity of the word catastrophic!  Pressed on copper fittings are now replacing soldered joints, where only silver brazed joints would be found at older properties from 65 years ago.  Aside from a separation failure, the long term effect of greatly increased turbulent flow, cavitation, and erosion as the water transitions from circular to hex to circular to hex again at its connections have yet to be realized.

No-hub has completely replaced the installation of extra heavy cast iron bell and spigot pipe having a pressed in or poured seal at its joints.  Solvent sealed plastic and PVC pipe is replacing steel pipe for condenser water service; actually driven by severe corrosion rates at new steel pipe more so than cost.

While each change in pipe construction is advocated as a superior evolution of mechanical engineering, most are driven by not only a lower cost and faster assembly, but also the elimination of better skilled and qualified workers.  More photos on this subject is available Here.

• ERW Seamed Pipe

Going back 30 years ago, seamed pipe would never be considered for any HVAC application due to the inherent threat of the seam itself and the greater possibility of failure.  Seamed pipe was common for fire systems only, and then only due to the absence of corrosion issues.  Given problems associated with either incomplete seams, incompatible weld filler, heat settings, and many other issues, using cheaper ERW seamed pipe was simply not worth the risk of an early piping failure.

Today, ERW seamed pipe is the standard for fire and HVAC services, and with it the inevitable failures at its seams.  We have found ERW seams having a deep internal V groove at least 60% incomplete – just not incomplete enough for the contractor or warehouse provider to have rejected it as per ASTM code.  Some fire system installation procedures call for orienting the ERW seam to the top of the pipe – both an acknowledgement to a common material problem yet with the unreasonable expectation that it will ever be followed.  More photos on this subject is available Here.

• Value Engineering

A stylishly elegant description and metaphor for saving money, or as most others would term – going cheap.  Many of the worst piping failures we have investigated can be traced to the money driven yet unqualified spreadsheet based elimination or downgrade of some critical component to a piping system.

We have seen the elimination of critical heat exchangers to heat pump systems, the substitution of galvanized steel for copper at domestic water service, and the substitution of schedule 20 pipe for heavier schedule 40 condenser water pipe – all prompted by the interest to reduce construction costs.   Yet no consideration to the longevity of the piping system itself.  Any large scale piping project will be approached by multiple piping representatives having access to pipe from every corner of the globe – providing major savings in the form of cheap foreign pipe from unlimited sources.

New pipe joining methods are promoted as better than those employed over the past 100 years.  Cheaper yes, but better – no.  Thinner materials may be partially justified based upon the longevity of older piping systems installed decades ago – yet fail to consider the near 10 times higher corrosion losses likely to occur.

Cost cutting discussions may begin with design engineers, or move to owners, or ultimately fall into the realm of the mechanical contractor.  For sure, any piping failure occurring due to a change in initial design specifications will be traced back to a decision to save money.

• Chemical Water Treatment

For many decades, building and plant engineers relied solely upon the use of chromate based chemical additives to provide the required corrosion protection of steel piping systems.  With even the most inferior application methods, often nothing more than an unmeasured scoop of chromate powder dumped into the cooling tower sump at irregular intervals, corrosion rates could often be maintained at or below 1 MPY.  Biological fouling was a rarely encountered problem due to chromate’s inherent toxicity.  Such trouble free operation ended, however, in the mid-1980’s – with the prohibition of all hexavalent chromate use in open water circulating systems throughout the United States.

Today, molybdate, phosphate, and other U.S. EPA approved chemical inhibitors rarely equal the effectiveness of past chromate treatments.  Molybdate, which was considered less effective than its predecessor chromate, is now being replaced by less effective phosphates due to excessive costs.  Though offering impressive corrosion suppression in bench test or laboratory settings, non-chromate programs rarely provide similar results under real world conditions.

Non-chromate treatments offer no microbiological or fungal control – thereby placing increased emphasis on the use of alternating biocide chemicals.  Unfortunately, biocides themselves have had their effective half-life reduced to approximately 6 hours by U.S. federal and state environmental authorities.  The result – a legal limit of the amount of biocide one can apply over a given period of time, as well as a legal limitation over its strength, effectiveness, and the time it will remain active.

• Galvanized Steel Pipe

Of the many failures we routinely investigate and document, the failure of galvanized steel pipe seems epidemic.  On one hand we have examples of extremely old properties from the early 1900s still operating without issue, but then new properties failing after 5 years.  We have documented 50 year old condenser water systems made from 12 in. threaded galvanized steel pipe still in good condition, the parallel cut marks on the surface being the remnant from 6 ft. long pipe wrenches and enormous strength.

Yet newer pipe seems to lose quality year by year.  Although claimed by the galvanizing industry that manufacturing has not changed in over 100 years, certain differences are apparent.  For older galvanized steel pipe, one can literally carve off the heavy zinc coating with a sharp razor, as if carving wood.  Today, the galvanizing coating is applied to its bare minimum and often poorly bonded to the substrate carbon steel.  Just rolling the pipe groove can fracture and flake away the coating both inside and outs, as we show at left.  This new fire protection system, from which this sample of pipe was obtained, is doomed to an advanced failure before it is even completed.

An interesting dichotomy exists in that the far superior quality older galvanized steel pipe is now finally reaching the end of its natural service life while newer pipe is also beginning to fail at an accelerated rate due to its far lower quality.

As one manufacturer commented to us after a trade show event where we discussed the advanced failure of galvanized steel pipe for fire protection systems, “You were unfair to not mention the benefits of galvanized pipe.  It will fail long before rust from carbon steel pipe will build-up enough to clog the fire sprinkler heads.”     We would certainly agree, but suggest it’s not really a good advertising statement.

• Green Influences

Politically correct demands favoring the green anti-global warming agenda are well known and documented, with green LEED credits a valued objective of government, most building properties, and management firms.  LEED accreditation is a most valued title.

Unfortunately, nature, chemistry, and the laws of physics do not exactly agree with some mechanical decision making found today within the building management industry.  While growing grass on the rooftop may increase the LEED credits for a building property, collecting rainwater for make-up to the cooling tower will have very negative consequences in the form of higher corrosion activity and advanced failures.  Slowing water flow by means of adding new VFD pump drives will save some energy, but at the cost of more rust and particulate settlement resulting in deep under deposit corrosion and premature piping failure.

Some pipe products even advertise LEED credits next to the other specifications about their pipe; a lower environmental assessment due to its third world production or fourth generation of recycled content which now carries a benefit to the purchaser.  With less energy used to manufacture a thinner pipe product, less energy to produce it due to a greater volume of recycled materials, lower energy used in the transportation of a lighter product, and faster installation, there is a most desired green benefit to installing low cost thin wall pipe.  The ultimate cost to have reached this status, however, is inevitable in the form of much lower service life.

The fact is that all global warming paranoia is based upon a hole in ozone layer over Antarctica which was actually discovered back in 1956, long before refrigerants widely existed.  Scientists believe it to have existed hundreds of years prior to that.  No air conditioning existed in cars nor in most homes before 1956.  Given that OSHA requires sensors in all refrigeration plants in the event of a heavier than air refrigerant leak, an event that may potentially asphyxiate any personnel in the area, the most fundamental question of how such heavier than air molecules have been able to reach the upper stratosphere many thousands of miles away has never been answered.

In fact, an active volcano almost directly under the ozone hole, Mt. Eribus, discharges over 1,000 tons of free chlorine per day.

• All Combined – Significantly Greater Threat And Less Service Life
  

Together, the combination of all the above named factors has placed a higher priority on corrosion control which did not exist 25-30 years ago, and which has raised the issue of chemical treatment, and the monitoring over its effectiveness to new levels of importance within those involved in building and plant engineering, maintenance, and operations.  Where there are no corrosion control measures or other preventative actions available, such as for sanitary waste service, the life of that piping system will be entirely dependent upon pipe quality.

© Copyright 2023 – William P. Duncan, CorrView International, LLC