Attachment_0019_--_Tech_Exhibit_1.7_--_Chiller_Heat_Exchanger_Evaluation.pdf

TECHNICAL EXHIBIT 1.7

CHILLER HEAT EXCHANGER EVALUATION

PART 1 - GENERAL

1.01 METHOD: Non-destructive testing using Eddy Current method.

1.02 OBJECTIVES: The testing shall be conducted in a professional manner to assure minimal tube failure by a technician having proper training, adequate experience, modern equipment, and using the latest techniques.

1.03 TECHNICIAN QUALIFICATIONS AND VERIFICATION:

A. The contractor shall provide qualified servicemen having previous experience performing eddy current testing on chillers.

The work history of the technician performing the eddy current testing shall demonstrate a minimum of 10 years of specific eddy current experience on absorption, Centrivac, and RHTB chillers.

B. The contractor shall submit training certificates of completion in nondestructive testing applicable to chillers and certification of a level 3 proficiency per the American Society for Nondestructive Testing (ASNT), Recommended Practice Number

SNT-TC-1A, “Personnel Qualification and Certification in

Nondestructive Testing.”

1.04 TEST INSTRUMENTATION

A. The test equipment shall be digital, portable and proven capable of accurate inspection of in-service heat exchanger tubes.

B. The power supply (basic instrument) shall have a wide range of frequency selections to assure full penetration of the various alloys and wall thickness. Adjustment of the signal amplitude and phase angle will be used for quantitative evaluation.

C. The scope shall display both the X and Y-axis. The displayed signal shall be maintained on the scope readout by means of memory retention.

D. The sensing probe housing shall be a material designed for maximum wear resistance. The components inside the probe shall be encapsulated in a moisture free manner. The sensing coils shall be arranged in a manner that will permit detection of any type of discontinuities. Circumferential as well as longitudinal defects shall be located.

1.05 INSTRUMENT CALIBRATION: The technician shall have in his possession a length of tube (standard) identical to the tube material to be tested. The standard shall have natural or artificial discontinuities representing the different types of defects normally found in heat exchanger tubes. The instruments shall be calibrated

(using the standard) so that the signals react in a predictable manner. Proof of instrument calibration shall be provided to the

COR prior to testing any RIA equipment. Calibration shall be checked at approximately one-hour intervals, more often if the existence of electrical interference and background noise is detected. Standards shall meet or exceed ASME codes.

1.06 TEST PROCEDURE:

A. With proper calibration attained, the technician's assistant will manually move the probe through the entire length of every tube to be inspected. The probe shall be moved at a speed not to exceed the reaction time of the test instruments.

B. The technician will monitor the scope display constantly while this test is underway. Use of alarm systems is unacceptable.

1.07 RECORD: Any tubes displaying unusual or detrimental indications will be recorded on a field report form. In addition, defective tubes may be recorded on a strip chart recorder for permanent filling, if applicable.

1.08 EVALUATION STANDARD:

Support Wear Reject tubes indicating 20 % or more wall penetration.

Pitting Reject 40% or more wall penetration

Erosion Reject 40% or more wall penetration

Corrosion Reject 40% or more wall penetration

Bulging Reject any tube exceeding 20% expansion

Cracks Reject all tubes with cracks

Restricted Tubes Reject tubes when restrictions

(scale, dirt) will not permit the probe to move through the entire length of tube.

1.09 FINAL REPORT:

The final report shall contain as a minimum:

(1) Arsenal name and address and dated cover letter to the COR

(2) Unit model and serial numbers for all chillers inspected

(3) Service Agency name and address providing testing

(4) Model and description of test equipment

(5) Job information sheet for each chiller showing tube count, type, material, length, frequencies, and type of defects, if any.

(6) Summary, containing any pertinent information about the unit, and recommendations for defective tubes.

(7) A copy of Field Report

(8) Copies of strip chart recordings, when necessary

(9) Tube sheet layout example

(10) Technicians name and copy of his certification

(11) Copy of original specification to do this work

1.10 SUBMITTALS:

A. Employee work history, training certificates, and level of proficiency per ASNT personnel qualifications.

B. Submit a copy of the final report in a 3-ring binder to the COR two weeks prior to the end of the performance period for his approval.

C. Copies of catalog descriptions of test equipment, age, and statement of ownership or rental of test equipment.

D. Two copies of final report.

END OF SECTION