To meet the demands associated with maintaining a world class hotel facility, Director of Engineering at Vancouver�s 385 room, Four Seasons Hotel, Mr. Priyan Jayetileke (P.J.) was often challenged to solve engineering problems that arose in properties under his direction. 

One of the most challenging problems he was faced with involved the corrosion of copper water lines servicing the hotel. 

The local area water supply comes from rainfall and snowmelt runoff that originates in the local mountains. The quality of this water is considered extremely high. Ironically, it is this same quality that is corrosive to metals that exist in metallic plumbing systems. Gaseous chlorine is used to disinfect the water supply to produce a bacteriologically safe water supply. This method of disinfection lowers the pH of an already �soft� water supply and creates an even more aggressive and corrosive water supply when in contact with metallic piping systems. The soft water supply in the area�s water system leads to an early replacement of copper piping systems which corrode quickly in this environment, often within seven to ten years. 

The 28 floor luxury Hotel, located in the downtown core was suffering with the ongoing effects of pipe corrosion resulting in pinhole leaks in its water lines. 

At first, the so-called traditional quick fix methods were used to stop pinhole leaks: gear clamps and replacement of sections of badly corroded pipe. These fixes were at best, temporary and involved cutting into walls, repairing the pipe and finally repairing the damaged walls/ceiling areas. This usually resulted in a direct loss of room revenue as the rooms were not available to let during this period of repair. 

Recognizing the scope of the problem he faced, P.J., looked for a long-term solution to the problems associated with a corrosive water supply and the pinholing of the hotel�s water lines. The typical solution usually meant re-piping. Re-piping meant long time lines associated with the project, extensive, expensive and messy renovation/repair work. Re-piping with copper pipe also meant that the corrosive action of the water on the pipe would start all over again once the water was turned back on.   The re-pipe alternative was deemed unacceptable and PJ went looking for a modern long term, healthy and cost effective solution. 

Researching the causes and cures of pipe corrosion, questions and answers surrounding matters such a health, corrosion prevention and product durability in the search of a long term solution were addressed.

It was clear that from a health perspective that internal corrosion of piping systems raised significant health concerns. A study in the Wisconsin Medical Journal stated: �copper contaminated drinking water maybe a fairly common cause of nausea, diarrhea, abdominal cramps and headaches especially among residents of new or recently remodeled homes.� 

The issue of harmful heavy metals leaching into the drinking water showed that the source of lead poisoning from water contamination was generally not in the community water supply but in the buildings piping system.   The American Water Works Association (AWWA) outlined actions to limit exposure to the leaching of harmful heavy metals and among those actions was the lining of water service lines. 

Understanding how corrosion worked in metallic piping systems showed that the best method of corrosion control also was to prevent water to metal contact. 

The most effective solution to stopping corrosion was to line the piping system. With what and how could it be done was the next series of questions. 

The answers to these questions was pipe restoration. A method of repairing and lining the piping system right within the walls of the building. No walls to cut out, no pipes to take out or replace, no asbestos to handle or dispose of. In the case of a  hotel, little if any, lost room revenue was an added benefit. 

What about the lining material, is it safe and will it last? The recommended lining material used in the process of pipe restoration was a non toxic epoxy lining. Epoxy lining materials have been used by the County Sanitation Districts of Los Angeles County and in the San Francisco region, the East Bay Municipal Utility District for over a decade. In terms of durability, pipe restoration coating material (epoxy) properly applied will be expected to give an effective life of at least 75 years.   So ideal were the application characteristics of pipe restoration that the US Naval Research Laboratory  completed lining sanitary piping systems aboard 12 US aircraft carriers and in 1995 stated: � the Navy intends to use this  technology for fast economical rehabilitation of drinking water systems aboard ship and shore facilities around the world� 

Engineering staff at the hotel were now convinced that pipe restoration was the answer and a project schedule and project cost was worked out with Pacific Pipe Restoration Inc., a licensee for ACE DuraFlo� Systems. 

Taking advantage of the flexibility of the pipe restoration technology and the seasonal swings in occupancy a working schedule was coordinated that allowed for traditional occupancy needs to be met. 

The pipe restoration process began by identify blocks of rooms associated with a common riser to be isolated and taken off line. Owing to the design of the plumbing system, 10 floors of rooms, 2 rooms per floor were isolated at a time. Water line sizes ranged from ½� to 2� and were all copper. 

Once the predetermined riser(s) and branch lines were identified and isolated, water was shut off, all taps were removed and the system was drained. 

The remaining steps in the Ace DuraFlo� method of pipe restoration involved drying the piping system, cleaning the interior of the piping system and then coating the interior of the piping system with a specially engineered NSF Standard 61 approved epoxy. 

The cleaning process is a purely mechanical process.  A closed loop system used in the ACE DuraFlo � process collects all abrading material and residual material without releasing any of the material or dust into the environment. 

The specialized NSF approved epoxy coating material was applied to the interior of the pipes. 

Once the epoxy was applied the system was left open overnight. The next morning all taps were reconnected and water was restored to the riser/system. Water/Pressure testing was completed and the system was restored to full operation. 

In this case study the risers, first hot water, then cold water, servicing 10 floors were isolated. The risers serviced 2 rooms per floor. In total the water lines to 20 rooms were resorted in 5 working days. Owing to the accessibility to the riser no walls were cut to access the piping system. All 20 rooms were back in service within the scheduled period of 5 working days, Monday morning to Friday afternoon. This process continued until all domestic hot and cold water lines to all 385 rooms were restored, a period of about 4 months. 

The use of pipe restoration technology solved the problem of pinhole leaks caused by the corrosive nature of the local water supply. The epoxy lining material now coating the interior of the pipe will effectively stop any corrosive activity on the piping system from occurring again. 

Minimal restorative work was needed to walls, ceilings or bathroom areas. 

No direct loss of room revenue was attributed to the pipe restoration process, as the rooms identified to be taken off line were excess inventory owing to seasonal occupancy. The pipe restoration process was quiet enough so as to not disturb any of the guests staying in this luxury Hotel facility. 

The direct cost savings of completing the restoration/repairs to the piping system using the ACE DuraFlo� method of pipe restoration over a conventional repipe were estimated at a 60% direct savings. Further non-estimated cost savings can be accounted for in no loss of room revenue and no indirect or consequential repairs that are typically associated with a re-piping job. 

THE ACE DuraFlo� SOLUTION - HOW IT RESTORES PIPES AND STOPS CORROSION

A simple fact: For corrosion in pipes to take place, water must be in contact with the metallic surface of the pipes.  As stated by Schneider and Stumm of Harvard University, on the topic of corrosion control: �clearly the best method is to prevent water to metal contact and a number of coating and plating procedures are used for this purpose.� 

The ACE DuraFlo�system of pipe restoration is designed to clean the piping system of encrustation build up and then coat the interior of the pipe with a NSF Standard 61 approved epoxy coating material, stopping any future water to metal contact. The size of pipes that can be restored using this process can be as small as 1/2� in diameter. Application within buildings has ranged from smaller walk-up style apartments to high rise facilities.  The ACE DuraFlo �system is ideal for the restoration of potable water and drain lines in virtually any setting. 

The ACE DuraFlo� system of pipe restoration is applied to pipes right within the walls eliminating the traditional destructive nature associated with a re-piping job. Typically, 1 riser system is isolated at a time and the restoration of the riser system is usually completed in 1 day with water restored the next day. For Hotel operators that means not having to take rooms off line for extended periods of time. Too, there are no walls to cut no large piles of waste, no dust and virtually no lost room revenue. Savings in time and costs when compared to a re-pipe are striking. Piping systems are typically restored in ½ the time and with 30% to 60% cost savings over a repipe job. 

Once applied, the epoxy coating creates a watertight barrier on the interior of the pipe and in turn prevents the water from actually coming in contact with the metallic surface of the pipe. Not only repairing the effects of corrosion but providing the best possible solution to stopping corrosion from reoccurring! 

EPOXY COATING - DURABILITY AND SAFETY

Epoxy coatings are characterized by their durability, strength, adhesion and chemical resistance, making them an ideal product to coat or line the interior of existing or even new piping systems. As a form of corrosion control, epoxy coating is recognized and used by both the County Sanitation Districts of Los Angeles County and in the San Francisco region, the East Bay Municipal Utility District. In terms of durability, pipe restoration coating material (epoxy) properly applied will be expected to give an effective life of at least 75 years. 

So ideal are the properties of nontoxic epoxy lining that the U.S. Naval Research Laboratory developed a nontoxic epoxy lining for water pipes. Later enhanced application techniques and testing convinced the US Navy to line sanitary piping systems aboard 12 aircraft carriers and in 1995 stated: �the Navy intends to use this technology for fast, economical rehabilitation of drinking water systems aboard ship and at shore facilities around the world.� 

Epoxy lining materials used in drinking waterlines are subject to strict health guidelines laid out primarily by the National Sanitation Foundation (NSF). NSF�s Drinking Water Programs have received widespread acceptance from the regulatory communities throughout North America. 

A COMPARISON OF TRADITIONAL AND MODERN APPROACHES TO REPAIRING THE EFFECTS OF CORROSION OF PIPING SYSTEMS

The time line associated with the restoration process versus a re-pipe will vary on the scope of work and the working environment. Typical experience however demonstrates that from start to finish, buildings can usually have their piping systems fully restored and back in full service in roughly ½ the time of a traditional repipe. For revenue properties such as hotel/motels this means an additional savings as rooms are kept offline for only a short period of time. 

With the elimination of the cutting out and replacing of walls and tearing out pipes, combined with the technique of restoring 1 riser system at a time the restoration process can be structured to meet the immediate and long term budgeting needs of the client. For example, many failures in the piping system occur first in the hot waterlines. The cold waterlines may not need replacing or restoring at the same time. The solution would be to manage the project by putting in priority the sections/areas that need immediate attention combined with the owners budgeting needs. 

A third alternative to re-piping or pipe restoration includes the use of liquid/chemical additives for corrosion and scale control in an encrusted potable water piping system which may be used subject to ANSI/NSF standards. The use of these products requires ongoing precise application and ongoing monitoring programs and is usually applied as part of a preventive program against corrosion and scale control.  The use of these corrosion control methods does not repair the damage that may have already taken place within the piping system. 

The ACE DuraFlo� restoration process cleans the interior of the piping system by a purely mechanical method, using no chemicals or harmful additives. The epoxy coating provides an impermeable barrier on the interior of the piping system, not only repairing the effects of corrosion but also stopping corrosion/encrustation from reoccurring. 

In a re-pipe, unprotected metal piping systems, once installed, are subject to the corrosive effects of the water as soon as the water is restored to the system. Even after a repipe has been completed the process of degeneration, corrosion, of the piping system begins all over again. 

In many cases, erosion corrosion caused from burrs, improper soldering, excessive turns in the piping system and �wear� on the pipe walls created by suspended solids can all be repaired by the ACE DuraFlo� system.  The cleaning process will eliminate the burrs and the ridges created by improper soldering.  The epoxy coating or liner will create a 10 mil to 20 mil covering, which when applied smoothes out the inconsistent surface of the pipe created by pitting, cavitation, improper soldering and burrs.  The epoxy coating is engineered to repair most pinhole leaks in the pipe. 

Pipe system design flaws such as undersized pipes, improper pumping facilities, and/or improper heating facilities cannot be fixed with the ACE DuraFlo� system.  If these design flaws exist, it is recommended that the ACE DuraFlo� system be used in conjunction with a redesign of a piping system thereby providing maximum efficiency, long life and a corrosion-free pipe system.