Document No.

GP 32-45
Applicability Group
Date 26 December 2005

Guidance on Practice for

In Service Inspection and Testing of Fired
Boilers and Heaters

GP 32-45

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ENGINEERING TECHNICAL PRACTICES
26 December 2005 GP 32-45
Guidance on Practice for In Service Inspection and Testing of Fired Boilers and Heaters

Foreword

This is the first issue of Engineering Technical Practice (ETP) BP GP 32-45. This Guidance on
Practice (GP) is based on parts of heritage documents from the merged BP companies as follows:

British Petroleum
RP 32-4 Inspection & Testing of In-Service Civil and Mechanical Plant -
Technical Guidance – Section B2 - Steam Boilers and Section B8 - Fired
Heaters.

BPOUS RPs
RP 20-4-5 In-Plant Inspection of Existing Boilers.
RP 20-4-6 In-Plant Inspection of Existing Fired Heaters.
RP 20-4-7 In-Plant Inspection of Refractories.

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Copyright © 2005, BP Group. All rights reserved. The information contained in this
document is subject to the terms and conditions of the agreement or contract under which
the document was supplied to the recipient’s organisation. None of the information
contained in this document shall be disclosed outside the recipient’s own organisation
without the prior written permission of Director of Engineering, BP Group, unless the
terms of such agreement or contract expressly allow.

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26 December 2005 GP 32-45
Guidance on Practice for In Service Inspection and Testing of Fired Boilers and Heaters

Table of Contents
Page
1. Scope........................................................................................................................................4
2. Normative references ...............................................................................................................4
3. Symbols and abbreviations.......................................................................................................5
4. Terms and definitions ...............................................................................................................5
5. Site Technical Practices, inspection plans and procedures......................................................5
5.1. General..........................................................................................................................5
5.2. Site Technical Practices ................................................................................................5
5.3. Inspection plans and procedures...................................................................................5
5.4. External inspection ........................................................................................................6
5.5. Internal inspection .........................................................................................................8
5.6. Refractory ....................................................................................................................11
5.7. Final inspection............................................................................................................13
6. Inspection frequency...............................................................................................................14
7. Operational surveillance .........................................................................................................15
8. Safety devices ........................................................................................................................16
9. Pressure testing......................................................................................................................16
10. Repairs and alterations...........................................................................................................17
11. Records and documentation...................................................................................................17
11.1. General........................................................................................................................17
11.2. Construction and design information ...........................................................................17
11.3. Inspection history.........................................................................................................17
11.4. Repairs and modifications ...........................................................................................17
Bibliography .....................................................................................................................................18

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26 December 2005 GP 32-45
Guidance on Practice for In Service Inspection and Testing of Fired Boilers and Heaters

1. Scope

a. This GP provides specific guidance for in service inspection and testing of direct fired
steam boilers and process heaters.
b. This GP applies to:
1. Direct fired steam boilers and process heaters, including essential ancillary
equipment, such as damper servo mechanisms, flue gas uptakes, and ducting up to
and including stack or isolating spade.
2. Waste heat boilers or generators using heat of flue gases.
3. Direct fired incinerators.
c. Outside scope of this GP are:
1. Waste heat boilers designed to pressure vessel and heat exchanger codes and using
heat of process fluids (refer to GP 32-41 and GP 32-48).
2. Non integral chimney stacks (refer to GP 32-46).
3. Deaerators and blowdown vessels (refer to GP 32-41).
4. Mechanical protective devices (refer to GP 32-47).
5. Flare tips and appurtenances (refer to GP 32-49).
6. Selective catalytic reduction equipment.

2. Normative references

The following normative documents contain requirements that, through reference in this text,
constitute requirements of this technical practice. For dated references, subsequent amendments to, or
revisions of, any of these publications do not apply. However, parties to agreements based on this
technical practice are encouraged to investigate the possibility of applying the most recent editions of
the normative documents indicated below. For undated references, the latest edition of the normative
document referred to applies.

BP
GP 32-30 Guidance on Practice for In Service Inspection and Testing of
Equipment - Management Principles.
GP 32-40 Guidance on Practice for In Service Inspection and Testing of
Equipment - Common Requirements.
GP 32-41 Guidance on Practice for In Service Inspection of Unfired Pressure

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Vessels.
GP 32-46 Guidance on Practice for In Service Inspection and Testing of
Equipment - Onshore Civils and Structures.
GP 32-47 Guidance on Practice for In Service Inspection and Testing of
Equipment - Mechanical Protective Devices.
GP 32-48 Guidance on Practice for In Service Inspection and Testing of Heat
Exchangers.
GP 32-49 Guidance on Practice for In Service Inspection and Testing of Special and
Other Equipment.

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26 December 2005 GP 32-45
Guidance on Practice for In Service Inspection and Testing of Fired Boilers and Heaters

NACE International (NACE)

NACE RP0170 Protection of Austenitic Stainless Steels and Other Austenitic Alloys
from Polythionic SCC during Shutdown of Refinery Equipment.

3. Symbols and abbreviations

For the purpose of this GP, the following symbols and abbreviations apply:

CUF Corrosion under fireproofing.

CUI Corrosion under insulation.

MOC Management of change.

NDE Non destructive examination.

4. Terms and definitions

For the purposes of this GP, the following terms and definitions apply:

External Inspection
Visual inspection of external parts of equipment while in or out of service.

Internal Inspection
Combination of visual, non destructive examination (NDE), and testing of internal parts of equipment
while out of service and entry to fire box, convection section, breaching, and stack are possible.

Final Inspection
Inspection of work to ensure completeness and adequacy of repair and to verify equipment cleanliness
prior to closing.

5. Site Technical Practices, inspection plans and procedures

5.1. General
This GP shall be read in conjunction with GP 32-30 and GP 32-40.

5.2. Site Technical Practices

a. This GP shall be adopted, modified, or supplemented by Sites into a Site Technical
Practice (STP).

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5.3.
b. The STP shall be approved by the Site Engineering Authority and form the basis for the
development of equipment specific inspection plans and procedures.

Inspection plans and procedures

a. Site equipment specific inspection plans, procedures and for fired heaters and boilers shall:
1. Cover equipment within scope of this GP.
2. Identify personnel responsible for specific defined activities.
3. Comply with applicable regulatory requirements.
4. Be developed for relevant design types
5. Be approved by Site Inspection Authority.

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26 December 2005 GP 32-45
Guidance on Practice for In Service Inspection and Testing of Fired Boilers and Heaters

6. Address internal and external components up to and including specification break

point for piping or other connected equipment.
7. Include inspection extent, methods, intervals and any special safety precautions.
b. Visual inspection, intrusive, and non intrusive NDE shall be used to ensure appropriate
level of integrity.
c. Inspection plans shall use a systematic process to identify potential damage mechanisms
and their form, location, and rate.
d. NDE methods of adequate sensitivity shall be used for detecting, sizing, and characterising
potential damage.
e. Normative references, bibliography, and requirements of this GP shall be used to develop
inspection plans and procedures.

5.4. External inspection

a. External inspection may be performed while equipment is in or out of operation.
b. External inspection procedures shall typically include the following, as applicable:
1. Ladders, walkways, platforms, and stairways for the following:
a) Corroded, bent, broken, or missing structural parts.
b) Loose, corroded, or missing bolts.
c) Worn stair treads and rungs.
2. Foundations of heater supports for spalling, cracking, settling, and deterioration.
3. Heater and boiler walls for corrosion, warping, discoloration, and excessively high
surface temperature.
4. Piping connections for CUI, leakage, and distortion.
5. Refractory for erosion and spalling.
6. Heater or boiler tubes shall be observed through observation ports for deterioration,
including:
a) Sagging or bowing of tubes.
b) Bulges.
c) Oxidation or scaling.
d) Cracking or splitting.
e) Corrosion or deposits.
f) Hot spots.

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g)
h)
i)
Flame impingement.
Tube supports for sagging, breaking, or bending.
Tube counterweight systems for deterioration.
Burners for proper operation and flame impingement onto internal parts.
8. Soot blowers for packing leaks and warping.
9. Breaching, ducts, and internally lined steel stacks for leaks, oxidation, buckling, and
cracked weld seams.
10. Externally insulated and fireproofed stacks for CUI or CUF.
11. Air preheaters for evidence of fouling or dewpoint corrosion.

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26 December 2005 GP 32-45
Guidance on Practice for In Service Inspection and Testing of Fired Boilers and Heaters

12. Forced and induced draft fans for evidence of excessive vibration or noise.
13. Stack or flue gas dampers for correct operation as viewed externally.
14. Compatible local and control room steam drum pressure and level indication for
boilers only.
15. Stack anchor bolts for corrosion or looseness.
16. Elevated flanged joints for corrosion due to escaping flue gases.

5.5. Internal inspection

5.5.1. Fired heaters and incinerators

a. Heater tubes and fittings shall be inspected as far as practical, as follows:
1. Tubes and fittings shall be inspected for overheating, corrosion, mechanical damage,
deterioration, and erosion.
2. Tubes shall be examined for bulging, blistering, cracking, sagging, bowing, and
chafing at supports or guides.
3. Wall thickness measurements of selected heater tubes and return bends shall be
performed and results recorded where wall losses are most likely to occur.
4. Carbon and chromium alloy steel tubes shall be examined periodically for
metallurgical change by hardness testing or in-situ replica metallography, as
applicable.
5. Tubes known or suspected to have been operating within creep range shall be clearly
identified and examined for evidence of creep by measuring diameter or
metallographic microstructures.
6. If tubes are cleaned by turbining, tube thickness and tube inside diameter (ID) shall be
measured for excessive metal removal after turbining.
b. Other common inspection techniques for heater tubes that shall be considered include:
1. Radiography to assess presence and successful removal of internal coke deposits.
2. Dye penetrant examination for cracking, especially austenitic materials, such as
thermocouple sheathing attachment welds.
3. Dye penetrant examination of austenitic stainless steel tubes for polythionic stress
corrosion cracking, especially those in non stabilised grades, as described in NACE
RP0170.
c. Tube rolls and header plugs shall be examined for leakage.
d. Tube supports, tubesheets, and furnace support girders shall be examined for deterioration

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or failure.
e. Supports and support connections shall be examined for cracking, oxidation, corrosion,
distortion, and bowing.
f. Refractory and insulation shall be examined for spalling, cracking, or other deterioration.
Refer to 5.6.1.
g. Breaching, duct, and stack linings shall be examined for deterioration.
h. Stack dampers shall be examined for deterioration from corrosion, wear, and excessive
heat.
i. Damper operation shall be checked to ensure free movement throughout full range.

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26 December 2005 GP 32-45
Guidance on Practice for In Service Inspection and Testing of Fired Boilers and Heaters

j. Air register dampers shall be checked internally for damage and to ensure correct
operation.
k. Stack integrity
1. Thickness survey of steel stacks shall be performed to determine structural integrity.
2. Minimum allowable thickness at which repairs will be made shall be established.
3. Areas of missing refractory, identified by either thermography or internal inspection,
shall be inspected for corrosion.
4. Concrete stacks shall be inspected in accordance with GP 32-46.

5.5.2. Boilers
Site specific inspection procedures for boilers shall address known areas of vulnerability.
Typical inspection procedures for direct fired utility boiler shall include the following as
appropriate:
a. Forced draft fan structural inspection, air ducting, burner box and air preheater integrity,
and functional examination.
b. Flue gas ducting and induced draft fan structural inspection.
c. External pressure parts, headers, and downcomers.
d. Soot blowers.
e. Steam drum and internals.
f. Water drum.
g. Furnace tubes, including pre clean inspection to define level of cleaning required to ensure
damage mechanisms are exposed. Refer to 5.5.1 for inspection requirements.
h. Superheater tubes and headers. Refer to 5.5.1 for inspection requirements.
i. Convection and economiser tubes. Refer to 5.5.1 for inspection requirements. Water side
scaling caused by salts shall also be checked.
j. Refractory. Refer to 5.6.1 for inspection requirements.
k. Burners and burner tiles.
l. Manholes and peepholes.
m. Safety valve overhaul (refer to GP 32-47).
n. Bellows and expansion joints.
o. Gauge glass connections.
p. Dampers and controls.

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q.
r.
s.
t.
Pressure test (refer to 9).
Safety valve float.
Isolation valves.
Blowdowns and associated equipment.
u. Protective instrumentation.

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26 December 2005 GP 32-45
Guidance on Practice for In Service Inspection and Testing of Fired Boilers and Heaters

5.6. Refractory

5.6.1. Inspection
a. Visual examination of refractory shall be performed to confirm suitability for continued
service.
b. Refractory lined equipment shall be inspected for:
1. Excessive cracking.
2. Cast refractory and anchor erosion.
3. Blanket type refractory anchoring failure.
4. Excessive fluxing (melting).
5. Bulging.
6. Spalling.
7. Fallout.
8. Voids.
c. If erosion, spalling, or fallout has occurred, measurement shall be made of depth or
thickness of remaining refractory.
d. Hammer test may be performed by striking lining with a non metallic mallet at 300 mm
(1 ft) intervals.

5.6.2. Repairs
a. Refractory areas requiring repair shall be field marked using contrasting colour spray paint.
Boundaries of repair area shall be accurately defined and painted.
b. Unless specified otherwise by Inspection Authority, refractory linings shall be repaired or
replaced under the following circumstances:
1. Steerhorn or Vee anchors are exposed to hot face.
2. For erosion resistant linings, areas of hexmesh have pulled away from wall.
3. For erosion resistant linings, hexmesh and refractory cupping exceeds:
a) 6 mm (1/4 in) depth for 19 mm (3/4 in) hexmesh.
b) 9,5 mm (3/8 in) for 25 mm (1 in) hexmesh.
4. Bulging or fallout has occurred towards bottom of lining, leaving upper lining
unsupported.
5. Erosion, fallout, or spalling has occurred near pressure parts or structural support

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members.
6. Cracking is judged severe and/or is accompanied by fallout. Hairline cracking up to
4 mm (5/32 in) in width is generally acceptable.
7. Cracking has occurred at locations that permit extensive air leakage.
8. Shell or casing hot spots have developed.
9. Hammer testing reveals void or reveals that refractory has separated from metal shell.
c. Refractory repair shall strictly comply with applicable refractory specification and repair
procedures.
d. Inspection of repair shall include:
1. Verification of complete removal of defective refractory.

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26 December 2005 GP 32-45
Guidance on Practice for In Service Inspection and Testing of Fired Boilers and Heaters

2. Examination of surface preparation.

3. Examination of anchor or hexmesh installation, including welding, to:
a) Ensure proper anchor pattern.
b) Bend test of random anchors.
c) Visual and hammer test of hexmesh welds.
4. Examination of prepared refractory materials, including pre-qualification of materials
and installers.
5. Observation of application.
6. Measurement of depth of application.
7. Verification of curing operation in accordance with procedure.
8. Re-inspection of lining using hammer test and visual methods.

5.6.3. Records and documentation

a. Permanent record of refractory lining inspection shall be made.
b. Inspection findings shall be recorded in such manner as to indicate any unexpected
conditions of refractory and anchoring system, including size and location.
c. Specialist Vendors performing this work shall provide certificate of compliance.
d. Drawing or sketches shall be updated as required to indicate current status of repairs or
replacement work in progress.

5.7. Final inspection

Upon completion of inspection and required repair work, boiler, heater, or incinerator shall
receive re-inspection to ensure completeness and adequacy of repair and verify internal
cleanliness before closing.

6. Inspection frequency

a. First inspection of heater or boiler shall be performed to confirm anticipated rate of

deterioration and identify unanticipated damage.
b. Comparison shall be made with initial inspection at time of construction and with design
records that detail considerations of corrosion, erosion, and other factors.
c. Factors to consider in allocating inspection intervals are listed below. Systems shall be in-
place, as applicable, to ensure that this data is available to the inspector:
1. Operating history, including temperature and pressure.

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3.
4.
5.
Feedstock and feedwater quality control.
Flow control through heater coils.
Firing controls (i.e., avoidance of flame impingement and local overheating).
Fuel quality, particularly sulphur and metals content that can lead to hot corrosion of
uncooled furnace parts, and acid dewpoint corrosion and fouling in heat recovery or
air preheater or economiser sections and in refractory lined ducting and stacks.
6. Process and firebox temperature measurement and control.
7. Steam temperature and drum water level control systems performance.
8. Remaining life of tubes based on measured corrosion rates, age of tubes, and
condition of tube supports.

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26 December 2005 GP 32-45
Guidance on Practice for In Service Inspection and Testing of Fired Boilers and Heaters

9. Age of parts operating in creep range and need to perform remaining life assessments.
10. Fatigue assessment based on number of shutdowns or startups compared with Vendor
design specification.
11. Peaking/ crack detection on shell seam welds as described in 5.5.2.e.
12. Specific inspection and maintenance history of equipment.
13. History of temperature, pressure, or other excursions.
d. Guidelines for establishing interval and extent of inspection are in GP 32-30.

7. Operational surveillance

a. During fired heater and boiler operations, the following monitoring shall be performed, as
applicable and the data shall be made available to the Inspection Authority or delegate:
1. Thermocouple readings shall be monitored to assess coking in coil, firing conditions,
and requirements for decoking.
2. Routine operator rounds shall include visual examination of fireboxes to ensure
flames do not impinge upon tubes.
3. Operating boundaries shall be defined for key process variables that affect damage
mechanisms. Associated monitoring requirements shall be established, including:
a) How and if key process variables are to be monitored.
b) When key process variables are to be monitored.
c) Who will monitor key process variables.
d) What action should be taken on excursions of boundaries (e.g., reporting and
evaluation).
b. Operating conditions can change rapidly. Inspection Authority shall be informed of any
changes that could affect safe life predictions.

8. Safety devices

a. If isolation (diverter) valves are fitted upstream of relief valves on boilers, management
practice to ensure that relief valves are protecting equipment from overpressure shall be
audited as part of boiler inspection.
b. Hot float testing of boiler relief valves to check hot setting pressure and blowdown settings
shall be performed after boiler has reached steady operation.

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9. Pressure testing

a. If no repairs or renewals are performed and inspections have confirmed integrity, pressure
testing shall be for sole purpose of confirming leak tightness of tubes and joints.
b. If tubing repairs or renewals are made or if mechanical integrity of tubes or pressure
envelope is in doubt, a pressure strength test shall be performed.
c. Pressure testing shall take place above minimum temperature specified by boiler design
code.
d. Pressure tests shall be witnessed and recorded by inspector.

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26 December 2005 GP 32-45
Guidance on Practice for In Service Inspection and Testing of Fired Boilers and Heaters

10. Repairs and alterations

a. Equipment repairs and alterations shall comply with normative references in this GP and
applicable industry codes and standards.
b. Alterations or modifications shall comply with site management of change (MOC)
procedure.

11. Records and documentation

11.1. General
Equipment files shall include information described in 11.2 through 11.4.

11.2. Construction and design information

Equipment serial numbers, Vendor data sheets, design specification data, design calculations,
and construction drawings shall be recorded.

11.3. Inspection history

a. Written inspection reports, inspection data reports, analysis of data, and inspection
recommendations shall be recorded.
b. Minimum required thickness and estimated remaining life for tubes shall be documented as
applicable.
c. During inspection, the heater or boiler shall be marked in such manner to permit
correlation of inspection findings to specific heater locations to ensure areas noted during
inspection findings may be positively located.
d. A drawing, sketch, inspection form, or equivalent shall be provided to accurately identify
points marked on the heater or boiler.
e. Inspection findings shall be reported by marking directly upon a drawing or sketch of the
heater or boiler, or the appropriate inspection form and in sufficient detail to permit
location and evaluation of reported condition.

11.4. Repairs and modifications

a. Reasons for and specific details of repairs shall be documented.
b. Changes made to design or mechanical components shall be recorded along with relevant
authorisations.
c. Supporting data and calculations for repairs or design changes shall be included in record.
d. Design changes shall be approved through site MOC procedure.

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26 December 2005 GP 32-45
Guidance on Practice for In Service Inspection and Testing of Fired Boilers and Heaters

Bibliography

BP
[1] GIS 72-002, Guidance on Industry Standard for Refractory Installation.

[2] GIS 72-004, Guidance on Industry Standard for Refractory Inspection.

[3] GN 32-004, Corrosion Under Insulation and Fireproofing (CUI and CUF).

[4] GN 32-017, Fitness for Service Assessment.

[5] GP 60-14, Guidance on Practice for Demineralized Water.

American Petroleum Institute (API)

[6] API Std 530, Calculation of Heater Tube Thickness in Petroleum Refineries.

[7] API RP 573, Inspection of Fired Boilers and Heaters.

[8] API RP 936, Refractory Installation Quality Control Guidelines - Inspection and Testing Monolithic
Refractory Linings and Materials.

American Society of Mechanical Engineers (ASME)

[9] ASME, Boiler and Pressure Vessel Code, Section I, Power Boilers.

[10] ASME, Boiler and Pressure Vessel Code, Section VI, Recommended Rules for the Care and
Operation of Heating Boilers.

British Standard Institute (BS)

[11] BS 1113, Design and manufacture or water-tube steam generating plant (including super heaters).

[12] BS 2486, Recommendations for treatment of water for steam boilers and water heaters.

Health & Safety Executive, UK (HSE)

[13] HSE Guidance Note PM5, Automatically Controlled Steam and Hot Water Boilers.

Safety Assessment Federation, UK (SAFED)

[14] SAFED, Guidelines on Periodicity of Examinations.

[15] SAFED, Guidelines for the Examination of Boiler Shell-to-Endplate and Furnace-to-Endplate Welded
Joints.

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