Inspection Procedure

32-SAIP-11 17 February 2020

Inspection of Air-cooled Heat Exchangers
Document Responsibility: Inspection Engineering Standards Committee

Contents
1 Scope ................................................................ 2
2 Purpose............................................................. 2
3 References........................................................ 2
4 Definitions ......................................................... 3
5 Responsibilities of Inspector ............................. 4
6 Corrosion Rates, Remaining Life,
and Inspection Interval ...................................... 7
7 Recommendation for Repairs ........................... 7
8 Alterations and Additions .................................. 7
9 Rerating Because of Operating Changes
in Temperature or Maximum Allowable
Working Pressure (MAWP) ............................... 8
10 Records............................................................. 8
11 Safety ................................................................ 8
Appendix A - Fin Fan Checklist ................................ 9
Revision History ...................................................... 11

Previous Issue: 14 September 2014 Next Revision: TBD

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 Document Responsibility: Inspection Engineering Standards Committee 32-SAIP-11
Issue Date: 17 February 2020
Next Planned Update: TBD Inspection of Air-cooled Heat Exchangers

1 Scope

1.1 This SAIP describes the responsibilities of inspector and inspection procedures to be
followed by the engineering inspection units and shop inspecting air-cooled heat
exchanger equipment (Fin-Fan Coolers).

1.2 This SAIP is intended to establish a standardized methodology by Saudi Aramco

inspection personnel in the implementation of inspection programs within Saudi
Aramco facilities. The SAIP shall not be included in purchase order or contract
documents issued to outside agencies.

2 Purpose

This SAIP provides a summary of Inspection activities for inspection of air-cooled heat
exchangers. It specifies inspection techniques to be used on heat exchanger
components, and defines inspector responsibility in repairing, altering, testing, and
maintaining records on heat exchangers.

3 References

3.1 Saudi Aramco References

Saudi Aramco Engineering Procedures

SAEP-20 Equipment Inspection Schedule
SAEP-343 Risk Based-inspection
SAEP-1161 Testing and Inspection (T&I) Reporting Procedure

Saudi Aramco Engineering Standards

SAES-A-004 General Requirements for Pressure Testing
SAES-A-005 Safety Instruction Sheet
SAES-A-007 Hydrostatic Testing Fluids and Lay-up Procedures

Saudi Aramco Materials System Specification

32-SAMSS-011 Air Cooled Heat Exchangers

Saudi Aramco Forms and Data Sheets

SA-2716 Specification Sheet of Air Cooled Heat Exchanger
SA-6238 Data & Operating Limits - Air Cooled Heat Exchangers

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 Document Responsibility: Inspection Engineering Standards Committee 32-SAIP-11
Issue Date: 17 February 2020
Next Planned Update: TBD Inspection of Air-cooled Heat Exchangers

Saudi Aramco Inspection Procedures

00-SAIP-80 Guidelines for Process Equipment Inspection

3.2 Industry Codes and Standards

American Petroleum Institute

API STD 661 Air Cooled Heat Exchangers for General Refinery Services
API Guide for Inspection of Refinery Equipment, Chapter VII

American Society of Mechanical Engineers

ASME SEC II, V, & VIII Boiler and Pressure Vessels

4 Definitions

Alteration: A physical change to a component described on the original Equipment

Data Sheet that affects the pressure containing capability of the heat exchanger.

Corrosion Allowance: Any metal thickness in excess of the minimum thickness

required by pressure design.

Corrosion Rate: The amount of metal thickness loss that occurs during a fixed time
period and is usually measured on mils per year (mpy).

Inspector: A member of the proponent's Operations Engineering Inspection Group or

is an assigned Shops Inspector.

Integrity: Means soundness - i.e., freedom from flaws or defects.

Equipment Data Sheet: A document furnished by the Manufacturer certifying that

materials, construction, and workmanship conform to Company and industrial
requirements.

Minimum Required Thickness, (Tm): As defined in ASME SEC VIII, is the

calculated thickness required based on the design pressure and temperature exclusive of
corrosion allowance. When the Tm limit is reached, action must be taken to repair,
retire, or derate the equipment.

Repair: The work necessary to restore a heat exchanger to a safe operating condition.

Rerating: Refers to any change, i.e., temperature, pressure, thickness, etc., which
would affect the maximum allowable working pressure. This change is to be
documented by revising the Safety Instruction Sheet and the Equipment Data Sheet.

Safety Instruction Sheet (SIS): Gives the minimum allowable thickness based on the
temperature and pressure for each component, and specifies test pressures (Refer to

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 Document Responsibility: Inspection Engineering Standards Committee 32-SAIP-11
Issue Date: 17 February 2020
Next Planned Update: TBD Inspection of Air-cooled Heat Exchangers

SAES-A-005).

Representative Specimen Tube: A tube removed from the top or bottom row for
destructive testing to evaluate corrosion damage.

5 Responsibilities of Inspector

5.1 General Inspection Guidelines

Check the Fin-Fan cooler’s drawing, construction code, material of heads and tubes,
material and dimension (diameter, length, and thickness).

Review the past history of the exchanger.

Read the Fin-Fan cooler file and note history of corrosion, tube failures, re-tubing
frequency, failures if any and other replacement, or repairs if any.

5.2 External Inspection

5.2.1 Primarily carry out external inspection for external leaks, external damage to
shroud, fans, and structure’s, Tube fins and or paint damage, external corrosion
to the header and nozzles. Look for and record any evidence of leakage around
the nozzles, flanges, threaded plugs, and rolled joints.

5.2.2 Check for signs of nozzle pipe strain and external corrosion.

5.2.3 Ultrasonically gage the thickness of header boxes and nozzles.

5.2.4 Establish the corrosion rates and check the remaining thickness against the Tm
(Refer to Safety Instruction Sheet).

5.2.5 Recommend repairs as necessary.

5.3 Exterior of Finned Tubes

5.3.1 Note the condition of the fins and the possible need for cleaning or straightening.

5.3.2 Check the exterior of the tubes for any mechanical damage, discoloration that
may indicate leakage, or corrosion attack.

5.3.3 Look for any evidence of vibration.

5.3.4 Recommend repairs as necessary.

5.4 Housing

5.4.1 Inspect the light gage steel housing enclosing the tubes for general condition.

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 Document Responsibility: Inspection Engineering Standards Committee 32-SAIP-11
Issue Date: 17 February 2020
Next Planned Update: TBD Inspection of Air-cooled Heat Exchangers

5.4.2 Inspect the top and bottom structural retaining members.

5.4.3 Inspect all bolting for tightness and that the shroud is not vibrating against the
tubes causing fretting.

5.4.4 Insure the shipping bolts between the housing and both header boxes are
removed. The unit cells shall be allowed to expand freely when put in service.

5.4.5 Recommend repairs as necessary.

5.5 Internal Inspection

5.5.1 Header Boxes and Nozzles

5.5.1.1 RBI assessment inspection plan shall be used to identify the required
amount and type of inspections as per SAEP-343 Appendix J.

5.5.1.2 If any fouling or corrosion is evident remove all plugs from the tube
sheets.

5.5.1.3 Check the headers and nozzles, before cleaning, and determine whether
there is any evidence of corrosion, erosion, or scale deposits.

5.5.1.4 Check the nozzle gasket surfaces, if possible.

5.5.1.5 Examine the plug sheet holes, plugs and gasket surfaces for stripped
threads and/or galvanic corrosion.

5.5.1.6 Inspect plugs and plug sheets for impingement damage by the process
stream.

5.5.1.7 Recommend repairs as necessary.

5.5.2 Tubes

5.5.2.1 Check the rolled joints at the tube sheet for leakage.

5.5.2.2 Inspect the tubes inlets at the tube sheet for signs of erosion or corrosion
and severity of grooving, at tube to tube sheet contacts, if any.

5.5.2.3 Inspect the interior surfaces of the tubes with a boroscope for cleanliness,
general corrosion and pitting. Check for pits with in the tubes and
measure the depth and compare it to the original thickness if possible.
Measure tube end thickness and compare to the original thickness.
If corrosion is a problem, request Magnetic Flux Leakage (MFL)
testing, Eddy Current testing or any other applicable Nondestructive
Testing (NDT) from Operation Inspection Division (OID) to get

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 Document Responsibility: Inspection Engineering Standards Committee 32-SAIP-11
Issue Date: 17 February 2020
Next Planned Update: TBD Inspection of Air-cooled Heat Exchangers

accurate measurement of pitting depth, cracks and average wall thickness.

5.5.2.4 If NDT MFL results indicate the need for additional tube bundle
evaluation, remove specimen tubes for corrosion evaluation.

5.5.2.5 Before plugging any tube, make sure it has been cut. The difference in
thermal expansion between the plugged tube and the operating tubes
may damage the rolling joint of the plugged tube resulting in a leak.

5.5.2.6 Observe the number of tubes already plugged and record it in the
equipment inspection records.

5.5.2.7 Plugging tubes shall be based on tube remaining life, corrosion rate,
actual thickness and minimum required thickness. The calculation
needs to be performed by Plant Engineering Organization.

5.5.2.8 Retubing the bundle shall be based on fin fan efficiency calculation
that needs to be performed by Plant Engineering Organization or CSD.

5.5.2.9 RBI assessment shall be updated based on the inspection findings

recommend repairs as necessary.

5.5.2.10 Recommend repairs as necessary.

5.5.3 Fan, Driver and Housing

5.5.3.1 Insure the motor start/stop buttons are locked out before entering the
fan housing area.

5.5.3.2 Insure the fan and driver guards are intact.

5.5.3.3 Inspect the fan blades for general condition, cracking, checking, and
chipping.
Commentary Note:

Fan blades must be installed as balanced pairs to maintain a balanced fan.

5.5.3.4 Inspect the fan belts for excessive wear, cuts and general condition.

5.5.3.5 Inspect the clearance between the fan blade tip and the housing
corrugated filler strips. Clearance should meet the manufacturer's
recommendation for best efficiency.

5.5.3.6 If present, inspect the condition of the corrugated filler strips and
retaining bolts.

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 Document Responsibility: Inspection Engineering Standards Committee 32-SAIP-11
Issue Date: 17 February 2020
Next Planned Update: TBD Inspection of Air-cooled Heat Exchangers

5.5.3.7 Inspect the hub assembly for possible cracking. If dismantled, hubs
should be penetrant tested.

5.5.3.8 Recommend repairs as necessary.

5.6 Hydrostatic Test

5.6.1 Witness hydrostatic tests.

5.6.2 Obtain test pressures from SIS sheets. Hold test pressures for a minimum of 1
hour.

5.6.3 Hydrotest bundle and inspect for leakage. Test media should either be sweet
water or condensate to prevent corrosion of tubes prior to startup (Refer to
SAES-A-007).

5.6.4 Plug all leaking tubes with tapered plugs of the same material as the tube.
Drive a plug into each end of the leaking tube. Do not seal weld plugs.

6 Corrosion Rates, Remaining Life, and Inspection Interval

6.1 Establish the corrosion rates of all the component parts of the heat exchanger.

6.2 Use the established corrosion rate and calculate the remaining life of all the components
and Tm for structure.

6.3 If needed, either make repairs to ensure the exchanger is good for the next scheduled
run period or revise the EIS to a shorter inspection interval.

7 Recommendation for Repairs

7.1 Prepare the repair recommendations after inspections have been completed and
corrosion rates established.

7.2 Obtain concurrence of the Operations Engineering Group where material changes, special
welding procedures, etc., are a part of the repair recommendations. The Inspection
Department and Consulting Services Department should be consulted in instances of
unexpectedly high equipment deterioration or unusual operating conditions.

7.3 When retubing is necessary, the proponent Operations Engineering Unit shall concur
that the tube material is adequate for the process conditions.

8 Alterations and Additions

8.1 Insure that a repair procedure has been established that will maintain the code integrity
of the equipment before any repairs, alterations, or additions are made.

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 Document Responsibility: Inspection Engineering Standards Committee 32-SAIP-11
Issue Date: 17 February 2020
Next Planned Update: TBD Inspection of Air-cooled Heat Exchangers

8.2 Verify that the proper materials have been purchased and they are stamped per company
and code requirements.
8.3 Verify that welding procedures and welders are qualified.
8.4 Verify that pre and post weld heat treatment or stress relieving procedures meet code
requirements.
8.5 Insure that radiographic techniques employed meet code requirements. Review and
interpret all radiographic films per code requirements.
8.6 Determine if magnetic particle and/or dye penetrant examinations are required by the
company and code requirements.

9 Rerating Because of Operating Changes in Temperature or Maximum

Allowable Working Pressure (MAWP)
9.1 Insure that the rerating is established in accordance with the requirements of the code
revision applicable at the time of rerating.
9.2 Obtain from Operations Engineering the approved revised data sheet (SA-2716) and
revised Safety Instruction Sheet (SA-6238).
9.3 Insure that a new nameplate is attached to the exchanger showing the rerated conditions.
9.4 Witness the hydrotest required to establish the rerating.

10 Records
10.1 Maintain a permanent and progressive set of records for each exchanger. These records
shall contain copies of the Equipment Data Sheet, Safety Inspection Sheets (SIS),
exchanger number, current condition of the equipment, previous repairs, alterations,
rerating, corrosion rates, and remaining life predictions.
10.2 Review records when operating conditions change which could affect the corrosion
rates. New corrosion evaluations and run length should be calculated.
10.3 Testing and Inspection (T&I) Reporting Procedure SAEP-1161 shall be used for the fin
fan post T&I reports.

11 Safety
11.1 Insure personal safety and that of any persons involved during inspections of equipment.
11.2 Insure that equipment is isolated from all sources of liquid, gases or vapors, prior to
making the internal inspection.
11.3 Insure the motor start/stop buttons (both local and remote) are locked out before
entering the fan housing area.

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 Document Responsibility: Inspection Engineering Standards Committee 32-SAIP-11
Issue Date: 17 February 2020
Next Planned Update: TBD Inspection of Air-cooled Heat Exchangers

Appendix A - Fin Fan Checklist

Report No.: Date Prepared:

Equipment No. & Service: Location/ Area: Plant No.:
Reason for inspection: Date Inspected:
P&E Inspector: Field insp. Supervisor: Unit Supervisor:

DESCRIPTION HEADERS TUBES DESCRIPTION

Material Design Press: Kg/cm2/psig
Thickness: mm/in Design Temp: °C/°F
Corrosion Allowance: mm/in Corrosion Allowance: mm/in
A=Acceptable, U=Un-acceptable, NA=Not Applicable, NI=Not Inspected
# ITEM A U NA NI COMMENTS
1. External Inspection
1.1 General
1.1.1 Properly screwed plugs
1.1.2 Equipment identification and number available
1.1.3 Name plate available and readable
1.1.4 Good coating
1.1.5 Flanges in good alignment
1.1.6 Check the fan blades for cleanliness.
1.1.7 Check the Plenum, fan ring, fan deck.
1.1.8 Check the drive assembly for any abnormality.
1.1.9 Check the ladder and platforms if they are intact.
1.2 Foundation/Supports
Condition of supporting columns/beams and fire
1.2.1
proofing
1.2.2 Condition of support bolts
1.2.3 Condition of foundation
1.3 Header Boxes and Nozzles
Look for and record any evidence of leakage around
1.3.1
the nozzles, flanges, threaded plugs and rolled joints.
Check for signs of nozzle strain and external
1.3.2
corrosion.
1.4 Exterior of Finned Tubes
Note the condition of the fins and the possible need
1.4.1
for cleaning or straightening.
Check the exterior of the tubes for any mechanical
1.4.2 damage, discoloration that may indicate leakage, or
corrosion attack.
1.4.3 Look for any evidence of vibration.

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 Document Responsibility: Inspection Engineering Standards Committee 32-SAIP-11
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Next Planned Update: TBD Inspection of Air-cooled Heat Exchangers

# ITEM A U NA NI COMMENTS
1.5 Housing
1.5.1 Inspect the top and bottom structural retaining
members.
1.5.2 Inspect all bolting for tightness and that the shroud is
not vibrating against the tubes causing fretting
Insure the shipping bolts between the housing and
1.5.3 both header boxes are removed. The unit cells shall
be allowed to expand freely when put in service.
2. Internal Inspection
2.1 Header Boxes and Nozzles
Check the headers and nozzles, before cleaning, and
2.1.1 determine whether there is any evidence of corrosion,
erosion, or scale deposits.
If any severe fouling or corrosion is evident remove
2.1.2
all plugs from the tube sheets.
If knife edge corrosion is noted on tube ends, and or
2.1.3 ID corrosion (pitting) is noted viewed from tube ends
remove additional plugs for inspection
2.1.4 If applicable, check the nozzle gasket surfaces
Inspect spot face (gasket surface) and threads for
2.1.5
mechanical damage and or corrosion.
Inspect plugs for corrosion and damage threads if
2.1.6
re-used.
Internal Corrosion (scales, pits, buildup)/Cracking
2.1.7 Describe location, appearance, and depth if
accessible.
Establish the corrosion rates and check the remaining
2.1.8 thickness against the Tm (Refer to Safety Instruction
Sheet)
Note if there is internal and external cracks,
2.1.9
erosion/corrosion, foreign deposit
2.1.10 Note the condition of attachment welds
2.1.11 Check external coating/painting
2.2 Tubes
Inspect the tubes inlets for signs of erosion or
2.2.1
corrosion.
Inspect tube ID/OD using appropriate NDT Method
(MFL, ECT, IRIS). As a minimum carry out tube
2.2.2
testing on a percentage of tubes as per SAEP-343
Appendix-J.
Perform corrosion rate, remaining life analysis for
each tube prior to installing plugs (boxing up). Tube
2.2.3 Tmin shall be per SAEP-343 Appendix-J and or
provided by Engineering. RL should be reviewed and
accepted by Corrosion Engineer.

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 Document Responsibility: Inspection Engineering Standards Committee 32-SAIP-11
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Next Planned Update: TBD Inspection of Air-cooled Heat Exchangers

# ITEM A U NA NI COMMENTS
Observe the number of tubes already plugged and
2.2.4
record it in the equipment inspection records.
2.2.5 Check tube leak marks behind the tube sheet
2.2.6 Get random RT taken on accessible tubes, around
headers and at midsection and evaluate corrosion
2.2.7 Check if tubes are sagged/bowed
2.2.8 Unacceptable tubes for plugging to be marked on site
2.2.9 Check the condition of stiffeners, tube spacers, tube
keepers and tube support cross members
2.3 Fan, Driver, and Housing
2.3.1 Insure the fan and driver guards are intact.
Inspect the fan blades for general condition, cracking,
2.3.2
checking and chipping.
Inspect the fan belts for excessive wear, cuts and
2.3.3
general condition.
Inspect the clearance between the fan blade tip and
the housing corrugated filler strips. Clearance should
2.3.4
meet the manufacturer's recommendation for best
efficiency.
Inspect the hub assembly for possible cracking.
2.3.5
If dismantled, hubs should be penetrant tested.
3. Hydrostatic Test
Obtain hydro test procedure from engineering prior to
3.1
hydro-test
Obtain test pressure from SIS sheets. Hold test
pressures for a minimum of 1 hour. Test pressure =
3.2
Design X 1.5 (Built before 1999 and 1.3 after 1999)
(Engineering to specify test pressure)
Visually inspect for plug leakage during the hydrotest
3.3 hold time and ensure that tubes are not leaking at
below platforms.
Plug all leaking tubes as per repair procedure
3.4
provided by Engineering
A=Acceptable, U=Un-acceptable, NA=Not Applicable, NI=Not Inspected

Revision History
17 February 2020 Revised the Next Revision and reaffirmed the content of the document.
15 September 2014 Revised the Next Planned Update and reaffirmed the content of the document.
18 April 2009 Editorial revision to change the primary contact.
Revised the “Next Planned Update”.

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