Letters of Reference

General DynamicsGeneral Dynamics Electric Boat


I want to express my appreciation for your timely response to Electric Boat’s urgent need for your heat exchanger cleaning service.

Your team of about a dozen personnel arrived on short notice and worked around the clock to complete the cleaning operation to the highest standards within 5 days. This effort was critical to support the completion schedule for this ship.

Many thanks for your excellent timely service.

F.J. Harris
Sr. Vice President, Programs
General Dynamics Electric Boat

Sole Source Justification – South Carolina Electric & Gas


Project Title Sole source justification for HX cleaning

Hennigan Engineering is recommended to be the sole source to high pressure water clean heat exchangers and piping as specified in RF 9. It is justified to consider only Hennigan to perform this work for the following reasons:

1. Hennigan has performed this type of work for the previous three outages. Each of the previous jobs were put out for bid and Hennigan was awarded the job each time based on the industry wide well known quality of their work. At VC Summer, the results of Hennigan’s work has been excellent.

2. The decision to high pressure water clean a number of the components scheduled for RF 9 was based on recent performance. Because the time to the outage is short, Hennigan is the best choice to perform this work based on their familiarity with the requirements at VC Summer.

Surface Prep & Coating – Calpine Tiverton Power

calpine power


Dear Tim,

Calpine Tiverton Power is a 265 megawatt combined cycle generating station located in Tiverton, Rhode Island. During our recent scheduled maintenance outage, we discovered that the coating in our steam turbine lube oil tank has failed to the point that corrective action was necessary before the plant could return to service. The Hennigan Engineering Company, Inc. was selected through our maintenance contractor, General Electric, to prepare and recoat the tank. As the plant was scheduled for imminent restart, rapid turn around of the tank surface cleaning, preparation, metal profiling, and coating application were critical. You included forced curing of the selected coatings product in order to avoid an additional eight days of ambient temperature cure. Calpine Tiverton Power was included in the project planning and implementation. Your safety awareness or this fast track repair was impressive and complied with Calpine’s outside contractor standards.

Thank you for your quick response and sensitivity to providing a solution to our tank coating failure, safely and within the limited time available.

Please feel free to use this correspondence as a recommendation to any potential clients.

Wishing you, your family and employees the best for the holiday season.

Robert C. O’Brien
Plant Manager
Calpine Tiverton Power

southern coMineral Scale Removal – Alabama Power


460 Gorgas Road
Parrish, Alabama 35580
Tel 205.257.1157


To Whom It May Concern:

Subject: Hennigan Engineering

Plant Gorgas Unit 9 began experiencing a Manganese scale buildup on our recently installed 304 Stainless Steel condenser tubes. This buildup was having a detrimental effect on our condenser cleanliness factor, therefore driving our unit heat rate up. We unsuccessfully tried several processes, including various mechanical scraper designs, to remove the Manganese buildup.

Hennigan Engineering was brought in to demonstrate their “Hydrolasing” technique in January 1998. Their process worked better than we expected and cleaned the condenser tubes to an almost new semblance. They worked well with our personnel, and cleaned our condenser with the unit still on line so we did not have to suffer a full derating.

We were well pleased with the results of their work as well as the professionalism of their crew. We have used Hennigan Engineering again during our fall 1998 outage on Unit 9 and have been just as pleased with the results. Until we find a more cost acceptable means of controlling our Manganese problem, we will continue to utilize Hennigan Engineering’s expertise in this area.

Team Leader – Operations
Alabama Power Company Plant Gorgas

BeloitBoiler Component Restoration – Beloit / PEOC


Fitchburg, MA 01420

Dear Mr. Hennigan:

On July 15,1996, I contracted your company to perform a particularly difficult Air PreHeater hydrolase cleaning.

The majority of the 2″O.D. tubes in the lower tube bundle of the Air PreHeater were plugged with a coal ash material that had formed during several previous fire hose washdowns in the air heater. This material had solidified into a very hard concrete-like substance that plugged the full length of many of the tubes. The situation resulted in unit inefficiencies, increased fuel consumption, and lack of O2 to the boiler which limited our power output.

In the past we have had competitors of yours come in to hydroblast and mechanically clean the Air PreHeater tubes. With no significant success. Our last option (excluding tube replacement) was to hire Hennigan Engineering. Had you not been able to get through we were prepared to cut out the airheater tubes and replace them.

I am writing to acknowledge the success of your personnel and equipment. The specialized hydrolase equipment your people designed for this job unplugged 100% of the Air PreHeater tubes. The boiler is now running at 105%. Thank you.


Chief Engineer

Public Service of NH LogoCrew Praise – Public Service Company of New Hampshire


Public Service Of New Hampshire

Dear Mr. Hennigan,

I am writing to compliment you on a job well done.

After the main condenser sleeving project and having followed that up with a tube sheet and tube insert epoxy coating system, I was understandably apprehensive about future hydroblast tube cleaning operations.

Your crew was perhaps one of the most motivated and well informed contractors of which it has been my pleasure to work with.

Each member of your crew was genuinely concerned about each and every tube. They understood the scope of the cleaning, the importance of following the cleaning plan and did it with a degree of professionalism that was truly refreshing.

Please pass along my comments to your employees and I look forward to working with you again in the future.


Chemical Supervisor
Newington Station, 165 Gosling Rd., Newington, NH 03801
Telephone (603) 431-4234

wolfcreek logoHEC Hydrolase vs. Mechanical – Wolf Creek Nuclear


Subject: This is a response to message # 16053

Re: Condenser Tube Fouling/Cleaning

Original From:

Wolf Creek Nuclear Operating Corporation provides the following response:

1) During May we performed hydrolase cleaning with the plant on-line, the circ water passes we were able to enter (4 out of 6 for which isolation valves held), the hydrolase process produced excellent results. We used 20,000 psi water pressure. This has allowed us to utilize our new on-line ball cleaning system installed in March since the tubes must be initially clean before starting up the ball cleaning system. Plant performance data shows the ball cleaning system to be effective at maintaining tube cleanliness. Over the past two summers we have used Sidtec cleaning rockets with some success, but this method does not have nearly as much operational flexibility as the ball cleaning system.

2) We attempted on-line chemical cleaning March ’95 using Betz 860. The process was terminated after cleaning one pass due to development of tube leak and the deleterious effects on secondary chemistry.

3) We have tried several methods of cleaning off-line during refuel outages. We have tried nylon brushes (once), Conco scrappers (twice), chemical cleaning (three times). Based on our recent experiences with Hennigan Eng. hydrolase cleaning, this method is the most effective and will be used as the manual cleaning process of choice during future outages.

4) N/A

5) N/A

Other info:

We have a once through system using lake water for cooling and our condenser tube material is 1-1/4″ OD 22 and 20 gauge 304 SS seam-welded.

Information Contact:

HEC Vendor Comparison – Entergy

M E M O R A N D U Mriverbend logo

Subject: Heat Exchanger Tube Hydrolasing

Design Engineering (George Hughes) and yourself completed a field trip to the Halliburton Industrial. Services. Inc. to demonstrate their hydrolasing equipment.

The demonstration was conducted as follows:

Two split sections of 3/4″ Cu/Ni tubing approximately 16″ long from the ICCS-E1A heat exchanger were used. Halliburton using a pipe vise to hold the tubing applied 10,000 psi to their hydrolasing tip and passed the lance through the first tube 4 times (2 Forward and 2 reverse). The process was repeated on the second tube but only 2 times through the second tube (I forward and 1 reverse).

The results when compared with a tube cleaned from the same heat exchanger, but cleaned by Hennigan Eng., showed a reduction in the cleanliness from 90% to approximately 70% clean. With a lot of streaking left behind. It should be noted that any streaking inside the tube sets up & galvanic cell. and heavy corrosion at that location will result.

In conclusion, it is Design Engineering’s recommendation to use Hennigan Engineering to clean any of the-RBS heat exchangers during RF-3 that need cleaning. Hennigan’s past performance plus their patented hydrolasing tip make them the logical choice to use here at RBS.

If you have any questions, please call.

Supervisor – BOP Design
Riverbend Nuclear Group

Attaboy Recognition – Maine Yankee Nuclear Plant

Maine Yankee

Attaboy/Attagirl Recognition Letter

To: Tim Hennigan, Hennigan

From: Engineering

Subj: Exceptional Performance

During today’s Morning Management Meeting you were commended by CED for your participation in the successful steam generator bowl water decontamination effort. The tools and process were specifically developed for use at Maine Yankee in preparation for a long sleeving campaign. The bowl decon achieved dose rate reduction levels of two to seven times pre-decon dose rates and is viewed as a great success for Maine Yankee as the anticipated dose to complete sleeving is expected to be significantly less than if the decon was not successful. CED and Plant Management congratulate and thank those that made this effort a great success. Excellent work!

Attached is your attaboy sticker.

We want to say thank for your fine efforts and a job well done. It’s people like you who make Maine Yankee what it is today.


Manager, CED

Acting Plant Manager

duke energy logoMetallurgical Analysis – Duke Power


Metallurgical Analysis Report

Sample No.: 1417 Station: Catawba Unit: N/A
Requestor/Dept.: CNS Component Eng.
Principal Investigator:
Submitted To:
cc: Nuclear Services

Equipment Description:
Admiralty brass KR heat exchanger tube, hydrolased for demonstration purposes

Background Information:
Hydrolasing was performed by a vendor on various areas of the 5/8″ diameter tube to demonstrate the cleaning process. Pressures of 10, 15, and 20 ksi were used at a traverse rata of 1 foot per second. Portions of the tube were left uncleaned for comparison.

These tubes are typically cleaned using plastic scrapers.
General corrosion has commonly been a problem; pitting corrosion has also been experienced. The cleaning cycle for KR heat exchangers was recently changed from 18 months to 9 months.

The appearance or the tube interior in the uncleaned condition and after hydrolasing at 10 and 20 ksi is shown in Figures 1-3. Uncleaned, the tube interior had red-brown to green-brown deposits with widespread general corrosion. Scraping away these deposits revealed a violet layer beneath.

Cleaning at 10 ksi produced an overall light violet color with patches of maroon. Several bright brass areas were exposed. The surface texture was not significantly different from that of the adjacent uncleaned area, and continuous features could be seen across the boundary area. A deep purple crystalline oxide lay beneath the light violet. Isolated areas where the silt was not removed were seen.

At 15 ksi, more bright brass was exposed, but the surface was still light violet overall. Scratching the violet oxide revealed red-brown deposits beneath. At 20 ksi, the surface was primarily bright brass with scattered patches of deep purple oxide.

The 10 ksi cleaning left much of the interior oxide intact, nearly as much as was present in an uncleaned section (figures 4 and 5). The 20 ksi cleaning removed nearly all of the oxide and much of the surface roughness as well (Figure 6).

There was no significant thinning of the tube wall at any cleaning pressure. The tube wall in an uncleaned section ranged from 0.043-0.049″; the minimum value measured from the 10 ksi section examined was 0.044″, and 0.043″ from the 20 ksi section.

No wall loss due to hydrolaser cleaning was seen in the brass tubes. The interior surface texture was not greatly altered by the 10 ksi cleaning; the rough surface of the violent oxide resulted from the texture left by the general corrosion. Only at 20 ksi were some of the protruding surface features removed, leaving an overall smoother surface without reducing the minimum wall thickness.

Scattered patches of the iron-rich deposit remained after the 10 ksi process, certainly a smaller amount than remains after cleaning by scrapers. These patches are not expected to initiate pits due to galvanic effects; other iron-containing material will be deposited shortly after the return to service, which should negate this effect.

Corrosion prevention is the main reason for cleaning the heat exchanger. The root cause of the widespread general corrosion is unclear; it is probably due to a combination of factors, including oxygen concentration, underdeposit corrosion, and mild galvanic effects of iron in the deposits. The violet oxide layer beneath the deposits serves to protect the base metal and there is no benefit in removing it. The thickness of the oxide layer was virtually unchanged by the 10 ksi hydrolasing, indicating that cleaning at 10 ksi effectively removed the silt and slime.

If the Metallurgy Lab can be of further assistance, please call.

HEC Hydrolase Erosion Analysis – ComEd



Subject: Summary of Hennigan Engineering Company Hydrolasing Demonstration

A hydrolasing demonstration was performed by the Hennigan Engineering Company at Braidwood Station on April 4, 1997. The testing was performed on an 8 foot long section of 1″ OD x 0.028 ” thick Type 304 stainless steel tubing supplied by SMAD, which had originally been installed in the Zion Unit 2 condenser. Using a dremmel tool circumferential defects measuring 60%, 70%, 80%, 90% and 100% through wall were machined on the OD surface of the tube. In addition, several pit-like indications were machined using a drill. The initial hydrolasing was performed using the following parameters:

The hydrolasing was witnessed by the SMAD-NDE Group. None of the Partially through wad defects deformed or leaked during the fisted exposures. None of the through wall defects grew in size.

After the initial testing results were acceptable, the nozzle was pressurized to 20,000 psi and allowed to sit at a mid-span (defect free) location for approximately 1 minute. Diameter measurements revealed no swelling and the exposed area was cross-sectioned and metallographically examined by the SMAD-Metallurgy Group. No thinning was detected. An unsupported free end of the tube was also exposed to a stationary 20,000 psi test. The free end vibrated violently and after approximately 20 seconds, the tube split axially for approximately 1″. Metallographic examination revealed deformation along the fracture edge, indicative of an overloading failure. It should be noted that the stationary, free end test is not representative of the loading encountered during heat exchanger tube hydrolasing.

Braidwood performed 20,000 psi cleaning of the tubes in 1 waterbox during AIR06. Subsequent eddy current examinations suggested the hydrolasing did not damage the tubes.


Hydrolasing -USNS Gordon -Boston Ship Repair, Inc.


I would like to take this time to express the quality of work that Hennigan Engineering performed during the repair of the USNS Gordon for Boston Ship Repair, Inc.

Hennigan Engineering showed professionalism in all aspects of the work that was performed in the shipyard. Work was done in a timely and efficient manner.

We look forward to working with Hennigan Engineering in the future.


Edward Snyder

Heat Exchanger Tube Cleaning & Hydrolasing – Mirant Canal, LLC


Dear Tim:

Looking over a long history of Hennigan’s service to Canal Electric Company, I wanted to take the opportunity to commend you for many jobs well done! In an era of uncertainty, it is reassuring to have the certainty of reliability, professionalism, and the commitment of excellence in service.

From a technical viewpoint, it has been our experience that Hennigan’s promise to restore and maintain maximum operating efficiency for every condenser and heat exchanger without harm to the tube materials, while inhibiting corrosion and extending tube life, has proven to be more than cost effective for Canal Electric. Your hydrolasing techniques have satisfied and exceeded all our project requirements.

We look forward to a continuing, mutually-rewarding relationship with Hennigan Engineering.

Thank you, Tim!


Michael Murphy
Planning Department

Rehabilitation of 48-Inch Riveted Steel Line- Providence Water Supply Board


In June 2001, Hennigan Engineering was selected to rehabilitate approximately 380-feet of 48-inch riveted steel pipe (washwater main) at our purification plant. The washwater main and thirty-six associated lateral lines were exhibiting severe corrosion and pitting due to coating failure. Used primarily for back washing of filters, this pipe is of critical importance to our treatment process and could not be removed from service during the work. The rehabilitation project, located in a very damp environment with difficult space constraints and high risk issues, consisted of removal and disposal of the existing lead based coating system, dehumidification of the space, filling of the pits, application of a new two coat urethane paint system, air quality monitoring, safety controls and complex coordination with other contractors while maintaining daily access to the space for our personnel.

Even though many unforeseen obstacles and conditions were encountered throughout the project, Hennigan Engineering completed the work professionally and diligently on time and within budget. The quality of the finished work is very high as evidenced by the very minute amount of touchup work required at the just completed one-year anniversary inspection. Given that this project could only have been completed in this quality manner by a very well organized, dependable and energized group, we were very impressed with Hennigan’s personnel from top to bottom. Hennigan proved to be highly skilled in all phases of the work described above.

Based upon Hennigan Engineering’s work on this project, we have no hesitation in recommending them for any lead paint removal or steel structure corrosion protection projects.


Jason D. Herrick, P.E.
Principle Engineer
Providence Water Supply Board