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Infrastructure Piping

The purchase of a high-rise condominium or co-op residence is a major and long-term expenditure in virtually every major American city often reaching above $250,000 and into the millions.  In addition, renovations can extend that cost by 50% or more.  Various considerations toward any such high-rise purchase include neighborhood, location, size, view, amenities, taxes, monthly maintenance fees, and investment value, etc.

Virtually ignored, however, is the physical condition and infrastructure expected to provide virtually unlimited and trouble free service from the time of purchase to possibly 50 years into the future.  As both our residential and commercial building properties age, certain unavoidable and inevitable corrosion related impacts to this infrastructure are now being realized by their property owners; failures indicating that many taken for granted and critically required services have reached the end of their useful service life.

For most purchases, the lobby decor is a far greater concern than the piping infrastructure that allows the building to function.  Piping systems are almost entirely hidden from view and therefore rate little to no concern.  Unfortunately, it is only when the realization that multiple walls of ones apartment need to be torn down in order to replace the piping behind them or a building where the pipe has naturally reached the end of its useful service life that the true magnitude of a pipe corrosion problem, , is fully realized.

• Deterioration Is Unavoidable

All buildings have the obvious maintenance concerns such as roofing, exterior stone, facade or facing, and large maintenance items such as boilers or refrigeration machines, but it is the lesser recognized piping systems which actually present the greatest interruption to tenant life and interior decor should they require replacement.

All high rise properties have common piping systems designed and installed similarly.  On the plumbing side there are the sanitary or bathroom and kitchen waste lines, the associated vent exhaust stack to the waste lines, and both domestic hot and cold water vertical risers.  All such services have smaller run-out or distribution lines between risers and individual fixtures.  For heating and air conditioning, otherwise known as HVAC, a greater variance in design options exist from centralized systems to individual package units per floor or per tenant.  Cooling condenser water may have a short travel to a main refrigeration chiller, or be supplied to individual units throughout the building.

Cold or hot cooling water can be supplied to window units or wall units through a two pipe system originating from the mechanical room, or it can be supplied through four pipes, 2 hot and 2 cold, to provide greater flexibility for tenant climate control.  A 3rd or 5th drain pipe is also required to remove condensate, or the condensed area moisture produced during summer cooling months.  Steam based heat is often supplied at older building properties, along with a condensate return line back to the boiler.

Fire sprinkler systems are now mandatory at almost all high rise buildings, with fire hose standpipe risers also common.  Natural gas is another service line common to almost all condominium or co-op building properties.  Storm drain is another entirely separate piping system.  In addition to their separate functions and layout, different materials are installed using different joining methods.  Copper and galvanized steel are common to domestic water systems; cast iron and ductile iron for waste, vent, and storm drain; and carbon steel for HVAC services.

• Different Consequences Due To Failure

The failure of different piping systems produce widely different levels of damage.  Any pressurized piping such as domestic water or HVAC cooling or heating can produce massive water damage.  For most moderate to larger failures, an impact can be felt in the neighboring apartments and 10 or more floors below due to the large volume of water loss typically occurring prior to shutting down the water flow.  Aged and frozen valves, and sometimes the absence of isolation valves altogether, often lengthen the time and therefore the damage occurring before the water can be stopped.  A 2 AM piping failure, strangely common where piping failures are concerned, may take 1 hour or longer before maintenance can reach the building property to affect a shutdown of the system.

As the below table illustrates, an enormous volume of water is possible for any major pipe leak where water pressures of near 100 PSI is very common.  For a thread separation failure at a 2 in. section of galvanized steel domestic water pipe at a typical 75 PSI of pressure, an approximate 329 gallons of water is released per minute.  Until someone arrives to shut down the line at possibly 30 minutes later, an astonishing 10,000 gallons of water will be unleashed to cause massive property damage.  For one commercial building property where this exact level of failure occurred in the middle of one night, damages exceeding $8.5 million occurred.

For all condominium or co-op properties, lower floor residences, or those at the lower area of any individual zone, are always under greater threat of water damage due to higher pipe pressures.

Water Flow (Gallons) At Various Pipe Sizes (Inches) And Pressures (PSI)

For all systems, threaded piping systems are at far greater risk of failure due to the approximately 50% wall loss present at the thread cut, and due to the greater potential for a total pipe separation – the worst form of piping failure.  Where brass valves are installed, an additional factor exists of galvanic activity accelerating the corrosion reaction between the brass and steel.

Failures at sanitary waste, vent, and storm drain piping are far less destructive.  However, because they do not produce as much water, they are typically only patched; leaving the larger issue of pipe deterioration to continue.  Low level waste or condensate leaks often remain undiscovered for years, and are commonly the cause of large scale mold contamination.

• Typical Piping Complexity

Viewing a high rise building plumbing and HVAC riser diagram provides only a brief glimpse to the complexity of such systems.  Different piping systems are installed using different methods, routes, and materials.  Plumbing related systems such as domestic water and waste are typically run together in “wet columns” within walls behind the various bathrooms and kitchen areas.  HVAC hot and cold piping supplied to below window fan units are commonly run at each exterior column which then connect to supply and return risers.

Just the domestic hot and cold water piping for a typical 32 floor high rise condominium property is presented in the below engineering riser diagram.  In addition to what is shown, separate overlaying drawings would exist for storm drain, natural gas, dual temperature heating and cooling, fire sprinkler, condenser water, chill water, sanitary waste, and vent piping systems as well; increasing its complexity 5 times or more.

All piping systems, depending upon their service, material installed, and most importantly age, will provide varying lengths of reliable service.  The quality of past maintenance will influence the service life of some systems, such as the HVAC piping, but has relatively no impact toward all others.  Every apartment will have some exposure and therefore a vulnerability to virtually all piping systems hidden behind their walls – making any failure a potentially damaging expense as a single event, and a massive multi million dollar capitol cost outlay where widespread pipe replacement is required.  Virtually all piping systems for a high rise building property span the entire building height at multiple cross sectional locations.

In the example above, at just the domestic cold and hot water service, 32 lengths or “risers” of piping cross through all 32 floors of the property – an estimated 32 risers X 11 ft. height per floor X 32 floors equals approximately 11,264 linear feet of pipe or greater than 2 miles of pipe not counting the horizontal run-out or distribution lines at additional thousands of feet.  A far greater number of risers comprising the remaining eight piping systems would also be present, adding easily another five times that volume of pipe to the building inventory.

• Common Problem Areas

Galvanized Domestic Hot Water

Galvanized steel pipe is highly vulnerable to heat since higher water temperature destroys its thin internal zinc protective coating.

Once this coating fails, corrosion activity becomes highly aggressive to produce not only pinhole failures, but also a constriction of the piping inside diameter due to the production of significantly greater iron oxide rust product from the original pipe steel corroded.

The cause of failure is exclusively due to water temperature and chemical and physical issues rather than other common speculation.  Failures will increase over time both in their frequency and severity – leaving total pipe replacement as the only option available.

Highest deterioration is always closest to the boiler or heat source, and to the first few floors of tenants served by the riser system.

Service life is dependant upon temperatures maintained and pipe quality – with most galvanized steel hot water systems capable of providing only 25-50 years of service life before replacement is required.

This is a very common problem to condominium and other building properties in the Chicago area and certain other areas.

Galvanized Domestic Cold Water

While hot water temperature is responsible for the advanced deterioration of galvanized steel pipe, cold and ambient temperature water will eventually lead to the same failure – just requiring more time.

Deterioration of cold water galvanized piping systems is related to the quality of the galvanized pipe and aggressiveness of the local water supply.

For New York City properties where water is soft but moderately aggressive, failure typically occurs within 50-60 years.  For areas such as Chicago having less aggressive water, we have document 80 year old properties still capable of providing another 50 years of service.

Like almost all piping products today, the far lower quality and corrosion resistance of most newly manufactured galvanized pipe means failure will occur far earlier than expected.  The complete failure of all galvanized steel domestic cold water pipe within an entire stadium facility within five years is just one of many examples we have been involved.

In addition to the obvious threat of leak or flow restriction, all galvanized pipe will eventually reach the condition of the examples at left, and raise further questions to water quality and possible health issues.  Few high-rise tenants could even comprehend that their drinking water travels through such piping.

Copper has now become the primary pipe material for domestic water systems due to its long service life and the lack of a significant corrosion product residual.

Dual Temperature

Of all piping systems, dual temperature heating and cooling systems present some of the greatest threat to condominium or co-op properties.  This is due to an inherent weakness of their design by installing inadequate insulation when first constructed.

Over decades of service, abundant moisture can easily migrate through the building envelope to penetrate the generally thin and often poorly installed insulation; then condensing at the cold pipe surface.

This produces an untreated corrosion condition to the outer pipe surface which will often destroy the pipe entirely, and beyond any possible repair.

This threat exists almost entirely hidden from view until the first failure occurs. Exterior pipe deterioration is often so severe that total pipe replacement is required.

Mold Contamination

Mold can cause extensive property damage, but it is the threat to human health that raises the greatest concern.

Many forms of mold, such as those common to bath tubs and showers, are relatively benign.  However, other forms such as Stachybotrys can produce toxic mold spores easily capable of migrating.

Unlike private homes, mold problems originating within a given tenant space can still impact surrounding apartments many floors away.  All high-rise building properties have moving air currents within their walls to enable a mold problem to migrate.

Mold will inevitably grow where water or moisture exists.  It uses various construction substrates such as wood, paper, and the cellulose in sheetrock or ceiling tiles as a nutrient base, and can even capture the airborne nutrients from septic gases released by a sanitary or toilet line waste leak.

In addition to slow piping leaks, insufficient insulation around dual temperature or chill water cooling pipe allows sweating of the pipe to produce the water necessary for mold growth.  In such examples, it is the paper and fiberglass which provides the nutrients for growth, and as the pipe travels from floor to floor through the concrete slab, so does the mold via its migrating spores.

Sanitary Waste

Sanitary waste lines are typically constructed of extra heavy cast iron or ductile iron, and have an expected service life of near 80 years or more.  Cast iron pipe corrodes and fails differently than steel pipe, and has the tendency to crack or fracture due to internal stresses created during its manufacture.

The greatest threat actually exists at their horizontal connection or run-out lines to individual drain outlets since threaded galvanized steel pipe is typically installed.

Most waste related leaks are small due to the absence of any pressure. Therefore, they can exist for months to many years before being discovered.

This provides a constant supply of moisture to propagate any mold condition.

Concealed away from view, and with abundant water, moisture, and nutrients available, mold will inevitably grow.  An internal passageway between floors and apartment walls, helped along by air currents commonly present, then allows generated mold spores to easily migrate to areas potentially far removed from the outbreak itself.

Any purchase of a high rise living space should include a close look at the age of the property and a thorough review of all maintenance records for evidence of pipe repair and other corrective actions.  Properties at 50 years and above, often those properties of distinction in demand, would certainly rate a closer look.  Although of far less interest than a tour of a newly renovated lobby, the pipe hidden behind almost every wall of most high rise properties carries the potential to substantially impact tenant life and finances should it require replacement.

An effective inspection through ultrasound is a costly expense, and will not address other areas of the property still capable of impacting the prospective residence should failure occur.

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