Ventiladores Turbo Axilaes de Techo 3ss-Maa0-00001

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Specification 3SS-MAA0-00001

STANDARD SPECIFICATION

FOR

INDUCED DRAFT FANS (AXIAL)

Bechtel Confidential

Bechtel Corporation 2006, 2003. Contains confidential and/orproprietary information to Bechtel and its affiliated companies which shallnot be used, disclosed, or reproduced in any format by any non-Bechtelparty without Bechtels prior written permission. All rights reserved.

BECHTEL POWER CORPORATION

FREDERICK, MARYLAND

NO. DATE REVISIONS BY CHKD APPROVALS

000 10/29/03 Incorporates PIP-Power-ENG-01-82.Issued for Use.

PNV KRL J. Olsonfor PFN

001 5/15/06 Added 1.4.e & i, 2.2.5.h, 2.2.8.c, 2.2.9.c, 2.2.10,2.2.14, 3.1.2.c, 3.2.4, 3.2.5, and 3.3.3. Revised1.1.a, b, g, k, m, n & o; 1.2.e; 1.3.2. a & c; 1.4.c &f; 1.7.1; 2.2; 2.2.1.a, b & c; 2.2.2.c, j, k & l; 2.2.5.a,b, e & f; 2.2.6.a, d, e & f; 2.2.7.a & e; 2.2.8.a, b, d,e & f; 2.2.9.b & c; 2.2.11.c; 2.2.12.a; 2.4.2.c & f;3.2.1; and 3.2.2.

Incorporated Lesson Learned 5111. Reissued foruse.

RV PNV J.Olsonfor PFN


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Bechtel Confidential Bechtel 2006, 2003. All rights reserved.

i Rev. 001

TABLE OF CONTENTS

Page

1.0 GENERAL 1

1.1 Work Included 11.2 Related Work Not Included 21.3 Service Requirements 31.4 Terminal Points 31.5 Quality Assurance 41.6 Submittals 41.7 References 5

2.0 PRODUCTS 6

2.1 Materials 62.2 Design Requirements 72.3 Motor Drives 162.4 Noise Levels 162.5 Fabrication 17

3.0 EXECUTION 18

3.1 Inspection 183.2 Shop Testing 193.3 Shipping, Handling, and Storage 193.4 Acceptance Test 19


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1 Rev. 001

STANDARD SPECIFICATION

FOR

INDUCED DRAFT FANS (AXIAL)

1.0 GENERAL

1.1 WORK INCLUDED

Design, furnish materials for, fabricate, test, and deliver variable-pitch, horizontal, axial-flow induced draft (ID) fans and electric motor drives with accessories in accordancewith this specification. The following items and services shall be provided, as aminimum:

a. Fans, each including the following:

Inlet box with access doors and housing

Drive shaft

Hubs with airfoil blades

Flexible coupling with coupling guard

Water-cooled lube oil supply unit for bearing lubrication, with standby pump

Water-cooled control oil supply unit for blade control, with standby pump

Seal air units with ducting and heating elements, if applicable

Servomotor

Control drive and control drive linkage

Bearings, pedestals, and soleplates

Bearing thermocouples

Bearing vibration monitoring system

Diffuser with support steel to grade

Single-bladed outlet dampers, if required

Stall probes

Required instrumentation


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2 Rev. 001

b. Outlet silencers, if required

c. Motor drives

d. Asbestos-free gaskets and bolting for flanged connections

e. One set of special tools required for erection, startup, and maintenance

f. Drawings and documentation

g. Shop priming and finish painting of uninsulated surfaces

h. Services of technical representative(s) for consultation during equipmenterection, startup, and testing

i. Startup spare parts

j. Insulation clips

k. Supply of acoustical/thermal insulation system including design (type, material,and thickness), if required to meet the specified noise levels

l. Nondestructive examinations (NDEs) and shop tests per paragraphs 3.1.2 and3.2 of this specification

m. Appropriate arrangement/provision to facilitate easy access to the rotatingassembly for maintenance requirements

n. Antifriction (roller) and ball bearings or, as an alternate, sleeve bearings

o. Expansion joints at fan inlet and between the damper and duct at fan outlet

p. Lubrication and control oil piping system between the fan and lube unit

1.2 RELATED WORK NOT INCLUDED

The following related work is not included:

a. Unloading, handling, and storage at jobsite

b. Foundations and anchor bolts

c. Installation of fan, electric driver, and accessories

d. Motor controls and external wiring

e. Thermal insulation

f. Ductwork


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3 Rev. 001

1.3 SERVICE REQUIREMENTS

1.3.1 Plant Location and Environmental Conditions

a. Plant location and jobsite environmental conditions are provided in the TechnicalSpecification for General Project Requirements (see parent material requisition[MR]).

b. Cooling water will be made available by the Buyer as required for miscellaneousservice requirements. Cooling water will be in accordance with the conditionslisted in the parent MR.

c. All supplied equipment will be located outside.

d. The instrument air will be supplied by the Buyer in accordance with conditionslisted in the parent MR.

e. Available electrical power sources for the operation of the supplied equipmentare as listed in the parent MR.

f. Site elevation and ambient temperatures are as listed in the parent MR.

g. Seismology and wind loading shall be in accordance with the parent MR.

1.3.2 Operating Conditions

a. The fans will operate in conjunction with fossil-fuel-fired steam generators. TheID fans will be located in the flue gas system.

b. The performance requirements are specified in the data sheets (see parent MR).

c. Minimum continuous flow for the fans will be approximately 15 percent of themaximum continuous rating (MCR) condition specified in the parent MR, exceptfor periods during steam generator startup and shutdown.

d. Maximum tip-speed of the fan shall be 500 fps (152 m/s).

e. Fuel, ash, and flue gas analyses will be provided in the parent MR.

f. The ID fan shall be designed for cycling operations in accordance with theanticipated operational data summarized in the parent MR.

1.4 TERMINAL POINTS

The Sellers supply shall terminate at the following points:

a. Sellers flue gas inlet expansion joint on inlet box


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Submit drawings, data, and manuals to the Buyer in the English language and in otherlanguages as specified in the parent MR and in accordance with the ANSI System ofMeasurement (foot-inch) or the International System of Units (SI), as defined in theparent MR. Express dimensions on drawings to the nearest 1/16 of an inch in the foot-inch nomenclature or to the nearest millimeter in the SI nomenclature. Corresponding

system of measurement units may also be included, expressed in the foot-inch or SInomenclature. Nominal floor and platform elevations shall be to the nearest 1/2 in. inthe foot-inch nomenclature or 1/100

thof a meter (1 centimeter) in the SI nomenclature.

1.6.2 Engineering Documents

Maintain the following documents on file at Sellers shop, and make available for reviewby Buyers representative:

a. Welder qualification records

b. Packaging and shipping (when applicable) procedures

1.7 REFERENCES

1.7.1 Referenced Codes and Standards

Comply with the latest edition, revision, or supplement of referenced codes andstandards in effect on the date of contract. In all instances of conflict between thisstandard specification or the parent MR and referenced codes and standards, follow themost stringent and conservative requirements.

AISC American Institute of Steel Construction

AMCA Air Moving and Conditioning Association

ANSI American National Standards Institute

ASME American Society of Mechanical Engineers

ASTM International American Society for Testing and Materials

AWS American Welding Society

IEEE Institute of Electrical and Electronics Engineers

ISA Instrumentation, Systems, and Automation Society

NEC National Electrical Code

NEMA National Electric Manufacturers Association

NFPA 85 National Fire Protection Association


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2.2.4 Foundations and Supports

a. Furnish heavy structural steel base flange or equivalent construction to supportfan housing structure. Design the support with sufficient rigidity, through itsthickness and its method of attachment to housing, to ensure an adequate

bearing surface for blocks and wedges to be used in setting up and leveling theequipment and to prevent local bending when wedges are driven in.

b. Provide a means of accessing and inspecting the internal fan bearings, airfoilblades, blade positioning linkages, hydraulic piping, lube oil piping,thermocouples, etc., without complete fan disassembly. Provide access toinspect the impellers from the upstream and downstream sides.

c. Provide supporting devices for access and removal of the diffuser and inlet box.

2.2.5 Fan Static Parts

a. Furnish fan housing(s) and inlet boxes of steel plate not less than 5/16 in.(8 mm) thick to preclude warping and excessive vibration over the entireoperating range, from no flow to full flow. Provide inspection doors to enablevisual observation of the fan hub, blades, and impeller casing. Provide doors onthe intermediate section that will allow blade replacement without disassembly ofinlet box or diffuser. Provide removable section so that rotor may be removed inthe same level, horizontal plane. Provide inspection doors for access to inlet andoutlet spaces, designed to be airtight when closed, convenient for opening andclosing, and raised to accommodate insulation. Fit a clean-out door to allow easyaccess to the inner tube. Design housing and inlet box to prevent excessivevelocities and minimize losses due to turbulence, friction, and erosion. Provide

low point drains for the fan housing(s).

b. Provide seals adjacent to the shaft or provide seal air system to seal the fanshaft from leakage where it passes through the inlet box and other points ofpossible leakage. Provide access to seals. Distortion of the fan housing duringnormal operations is not acceptable.

c. Install required stiffening of diffuser, intermediate piece, and inlet box at theSellers or subsuppliers manufacturing facility.

d. Split the intermediate piece horizontally to allow easy access to the main bearingassembly.

e. Provide an impeller casing that is lathe-turned on the inner surface to ensuresmooth clearance between the blade and the casing. Fit an inspection cover togive access to the blades. Furnish impeller casing not less than 3/8 in. (10 mm)thick after machining.

f. Provide a one-piece diffuser unless otherwise specified in the parent MR. Toensure high fan efficiency, provide an optimized design to recover static loss due


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The torsion natural frequencies of the combined fan and the motor shaftsystem shall be at least 15 percent away from any multiples of fanoperational speed.

The First Critical Speed, as defined in AMCA Publication 801-01, of the

combined fan motor shaft system shall be at least 60 percent above the fanoperational speed.

The First Resonant Speed, as defined in AMCA Publication 801-01 andapplicable for rigid supports, of the combined system of rotating parts (suchas rotor and impeller) and stationary parts (such as bearing housing,bearing supports, and, for sleeve bearings, the bearing oil film) shall be atleast 30 percent above the fan operational speed.

To ensure smooth running, resonant speeds shall be well away from anymultiple of fan operational speed.

g. Design the fan so that blade replacement is possible through an inspectioncover in the impeller casing and so that overhauls can be done withoutdismantling the fan casing.

h. Provide a shaft made of forged high-grade steel. Thermally stress relieve andultrasonically test the shaft.

2.2.7 Bearings

a. For the main bearing assembly, provide roller and ball bearings or, alternatively,sleeve bearings, with a forced lubrication system. Include a locating bearing and

a floating bearing to allow extension/contraction of the shaft due to temperaturevariation. If sleeve bearings are selected, provide the details for handling radialand thrust loads.

b. Furnish radial bearings and thrust bearings with a minimum L-10 lifetime of100,000 hours and 70,000 hours, respectively. Subject the main bearingassembly to a fully instrumented full-speed, full-load running test with therotating elements for 812 hours before delivery.

c. Furnish a complete Bentley Nevada, or approved equal, seismic vibrationmonitoring system in a weatherproof housing with power supplies, monitors, andone velometer point per bearing. Provide a 4-20 mA dc output from eachmeasurement. Furnish an independent monitoring system for each fan. Providea NEMA 4X junction box for transducer termination strips, with monitorsremotely located in NEMA 12 cabinets.

d. Prepare the fan for installation on a concrete foundation provided by the Buyer.Provide anchor bolt requirements, bolt material, diameter, length, andconfiguration.


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12 Rev. 001

e. Furnish thrust bearings for airfoil blades.

2.2.8 Lubrication

a. Provide lubrication for fan and motor bearings suitable for service andtemperatures to be encountered. The hub may be self-lubricated or forcedlubricated. The blade bearing shall be grease or sump-oil-bath lubricated. Duringrun-up and coast-down, the system and design shall be capable of providingsufficient lubrication to the remaining movable hub parts.

b. For the main bearing assembly, provide antifriction bearings that employ a forcedlubrication system. Provide adequate bearing-oil reservoirs to provide sufficientlubrication during fan coast-down if forced lubrication is lost.

c. For sleeve bearing designs, provide a forced lubrication system. Include alocating bearing and a floating bearing to allow extension/contraction of the shaftdue to temperature variations. Provide a spherically seated steel body for the

radial sleeves and tilting pads for axial thrust. Sufficient lubrication shall beavailable to maintain the oil film at low speeds during fan coastdown.

d. Provide the lube oil supply unit with two identical oil pumps, filters, and water-cooled oil coolers (one for service and the other for standby duty), complete withan oil reservoir, heating elements, valves, full instrumentation, etc. Before theassembly, grit-blast and paint oil reservoirs to make them thoroughly clean andfree from foreign matter. Grit-blasting and painting shall not be required for oilreservoirs made from stainless steel.

e. If the motor requires forced lubrication, the design shall incorporate the use of

the fan lube oil system.

f. Design the lubrication system to serve both the fan and associated motor drive (ifrequired) and furnish it complete with the following, as a minimum:

Oil reservoir with a capacity equal to 10 minutes of the pump rating, as aminimum

Two motor-driven pumps (one pump to serve as the main pump and one toserve as a standby that shall activate upon loss of pressure in thedischarge line)

Water-cooled oil cooler

Duplex oil filter (1.6 mil [40 micron] minimum) capable of being servicedwhile the fan is operating

Reservoir immersion heater with sufficient heating capacity to meet theminimum outside temperature stated in the parent MR, complete withthermostat and capable of being serviced without draining the reservoir.


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13 Rev. 001

Oil level indicator

Sump drain

Pump discharge pressure and temperature gauges

Two pressure switches (one to activate the standby pump and one for theBuyers use)

2.2.9 Control Oil

a. Design the control oil flow to be adjustable to modify blade closure time.

b. Provide a control oil unit to supply the required oil flow for the hydraulic cylinder,complete with the following, as a minimum:

Oil reservoir with a capacity equal to 10 minutes of the pump rating, as a

minimum

Two identical motor-driven pumps (one pump to serve as the main pumpand one to serve as a standby that shall activate upon loss of pressure inthe discharge line)

Water-cooled oil cooler

Duplex oil filter (1.6 mil [40 micron] minimum) capable of being servicedwhile fan is operating

Reservoir immersion heater with sufficient heating capacity to meet theminimum outside temperature stated in the parent MR, complete withthermostat and capable of being serviced without draining the reservoir

Oil level indicator

Sump drain

Pump discharge pressure and temperature gauges

Two flow switches (one to activate the standby pump and one for theBuyers use)

c. Furnish a fail-in-place hydraulic control drive to modulate the blade position, incompliance with NAPA-85 requirements.

2.2.10 Outlet Dampers

a. Provide isolation dampers at the gas outlet of the transition piece of each ID fan,if more than one fan is in continuous service.


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c. Provide sufficient instrumentation to monitor fan and hydraulic systems forproper operation. As a minimum, the following parameters shall be monitored toensure proper operation:

Bearing temperature

Bearing vibration

Servomotor actuator torque

Motor operation

Fail-in-place blade pitch control system on loss of hydraulic pressure, withalarm to DCS

Hydraulic system pressure, temperature, and level

Lubricating system pressure, temperature, and level

Seal air pressure

Stall detection system, complete with probes, transducers, and alarms

2.2.12 Flexible Couplings and Coupling Guards

a. Furnish each fan with flexible-gear or double-flexible steel disc-pack couplingswith all-metal construction and steel body with angular and axial flexibilitysufficient to allow for thermal expansion and other movements of fan stator and

shaft as well as motor stator, including the shaft. Select couplings to transmit,with an appropriate margin, the maximum torque that can be developed under allstarting and operating conditions.

b. Machine finish and balance motor half couplings to the motor manufacturersspecifications and coordinate this information with the motor manufacturer. Shipmotor half couplings, together with the Sellers recommended dimensions andmounting instructions, to the motor manufacturer for mounting. Identify bothhalves of each coupling to ensure reassembly of the correct pair. If fancomponents can be field erected with the fan half coupling in place, mount thehalf coupling in place before shipment. If the fan half couplings cannot be shopmounted, ship them loose with the fan.

c. Furnish coupling guards and other necessary guards to eliminate safety hazardsand to comply with the requirements of OSHA, local regulations, and other

jurisdictions at the jobsite. Furnish coupling guards that totally enclose thecouplings and shafts, extending from bearing to bearing if outside of the inletbox. Split each coupling guard along the horizontal centerline, so that the top halfcan be removed without disturbing the lower half.


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16 Rev. 001

2.2.13 Seal Air System

a. Provide a seal air system to cool and prevent flue gas from entering the hub offan rotating parts (other than fan blades), inlet box inner tube, intermediatepiece, and diffuser center housing.

b. Provide the seal air system complete with necessary pressure detectors,pressure indicators, ductwork, filters, silencers, and expansion joints. Seal airblowers shall be controlled from a Seller-supplied central control panel.

2.2.14 Expansion Joints

a. Expansion joints at the inlet box and at the outlet of the fan discharge chambershall be Corten or equal steel of sufficient thickness. Flexible parts shall be madefrom material suitable for the flue gas conditions as specified in the parent MR.

b. Provide expansion joints of 1/8-inch (3 mm) minimum thickness suitable for the

flue gas conditions, including acidic conditions and ammonia slip, that arecapable of withstanding any upset conditions as specified in the parent MR.Design expansion joints with interior baffles to prevent ash accumulation, ifspecified.

c. Expansion joints shall be suitable for service where frequent boiler startups willnot lead to failure due to acid attack. Furnish the expansion joints complete withangle, interior seal plates, and exterior hoods for rain protection. Fabricateexpansion joints in one piece or the largest pieces subject to shippingconstraints, so that field erection time is minimized.

2.3 MOTOR DRIVES

Furnish motor(s) in accordance with the parent MR. Furnish outlet damper motor drivesin accordance with the parent MR.

2.4 NOISE LEVELS

2.4.1 Fan and Drive

Provide acoustic insulation to limit noise emissions from the ID fan casings to a soundpressure as specified in the parent MR. These levels are applicable under free-fieldsound propagation conditions and are exclusive of any extraneous background noise

from other plant sources.

2.4.2 Silencers (if required)

a. Design the silencer outlet noise performance to meet the following dynamicinsertion loss requirements:


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31.5 63 125 250 500 1k 2k 4k 8k (Hz)

5 9 20 31 22 15 12 9 4 (dB)

b. These requirements are preliminary, with project-specific requirements currentlybeing developed. Design the silencers for these criteria, as a minimum, and be

capable of providing a silencer that meets all reasonable noise emissions.

c. Design silencers to limit internal gas velocity to 5,000 fpm (25 m/s).

d. Design silencers to limit flange-to-flange pressure loss to 1.0 in. (25 mm) w.g.

e. Construct silencers of Corten or equal steel of sufficient thickness to providestructural strength for the maximum flow and to provide sufficient corrosionallowance for a projected 30-year life. Provide casing plate steel of 3/8 in.(10 mm) minimum thickness.

f. Provide reactive-type silencers.

2.5 FABRICATION

2.5.1 Welding

a. Perform and document all welding in accordance with applicable U.S. standards.

b. Perform all preheat, welding, and heat treatment in accordance with theapplicable AWS D1.1 for casing and AWS D14.6 for rotating components.Qualify welding procedures in accordance with the applicable code. Weldingdone to AWS D1.1 may be performed with a prequalified procedure, whereallowed.

c. Coat final weld-end preparations for carbon steel pipe, structural/miscellaneoussteel, plate, etc., with a weldable primer (Bloxide or approved equal). Weldableprimers containing zinc are not acceptable for steel that attaches to austeniticstainless steel. Extend the coating at least 3 in. (75 mm) from the prepared end.

2.5.2 Stress Relieving

a. Before stress relieving, machine or grind the rotor to eliminate stress risers at theinlet and periphery of the wheel due to fabrication and handling procedures.

b. Stress relieve wheels after fabrication in accordance with AWS D14.6.

c. After stress relieving, test welds in the rotor by magnetic-particle or liquid-penetrant inspection, to ensure that no cracking has occurred during the stressrelieving process.


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2.5.3 Cleaning and Painting

Provide surface preparation, painting, and cleaning in accordance with the parent MR.

2.5.4 Nameplates

Provide each axial ID fan with a permanent, corrosion-resistant nameplate showing thepurchase order number, Buyers equipment tag number, equipment serial number, andservice conditions. Refer to the Technical Specification for General ProjectRequirements (see parent MR) for additional requirements. Locate the nameplate sothat it is completely visible after equipment installation.

2.5.5 Preassembly

Before shipment, preassemble all components being furnished under this specificationto the maximum extent possible, considering the selected means and route oftransportation to the jobsite. Avoid the use of escort loads, if possible.

3.0 EXECUTION

3.1 INSPECTION

3.1.1 Inspect and test all materials and work pursuant to the purchase order.

3.1.2 Nondestructive Examinations

a. After stress relieving each fan rotor weld, examine it by magnetic-particle and/orliquid penetrant methods, using procedures complying with ASME B&PV CodeSection V.

b. Use only acceptance criteria for magnetic-particle or liquid-penetrantexamination that are in accordance with ASME B&PV Code Section VIII, Div. 1,

Appendices 6 and 8, respectively.

c. If cast iron or cast steel blades are provided, conduct RT examination of thesample blades from the foundry before machining in accordance with ASMEB&PV Code Section V.

d. Employ the yoke method of magnetic-particle examination for auxiliary surfaceexamination only (e.g., detection of arc strikes and inspection of as-machined

surfaces).

e. Ultrasonically test the fan shaft in accordance with ASTM A388. The acceptancecriterion for straight beam UT examination shall be not more than 25 percentloss of back reflection.

f. Radiograph any full penetration welds on the rotor welds in accordance withASME B&PV Code Section V. Use only acceptance criteria for RT examinations


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that are in accordance with ASME B&PV Code Section VIII, Div. 1, Para. UW-51,unless the manufacturers fracture mechanics (F-M) analysis indicates that largersubsurface flaws are acceptable. If the manufacturer proposes alternative RTacceptance criteria, submit such an F-M analysis for Buyers review. No cracksare permitted in any case.

3.2 SHOP TESTING

3.2.1 Perform a natural frequency test of the assembled (hub and blades) rotatingelement. The natural frequencies measured shall be well away from at least the fourmultiples of the fan operational speed.

3.2.2 Statically and dynamically balance fan rotor assembly, hub, and shaft, at theSellers shop. Limit residual unbalance in accordance with the criteria specified in ANSIS2.19 (ISO Standard 1940) to a balance quality of 1.8. The intermediate shaft, if any,shall also be statically and dynamically balanced. Before delivery, subject the main rotorassembly (hub and blades) to a full-speed test that is 12 hours in duration. This test

shall continuously cycle the hydraulic blade control mechanism through its full operatingrange.

3.2.3 Statically and dynamically balance the hub and blades separately, so that any setof blades will fit any hub without rebalancing.

3.2.4 The hydraulic cylinder shall be tested for maximum force and speed in bothdirections and shall be free from any oil leakages and operating properly.

3.2.5 Shop-assemble each outlet damper with the motor and drive links, including thelimit switches, before final inspection and testing.

3.3 SHIPPING, HANDLING, AND STORAGE

3.3.1 Set the rotor with main bearing in a cradle, with the bearing journal resting firmlyon the base of the cradle.

3.3.2 Crate or skid the blades, soleplates, and dampers. Box or crate smallmiscellaneous parts and hardware.

3.3.3 If the outlet damper and its components need disassembly for shippingrequirements, match-mark the parts.

3.4 ACCEPTANCE TEST

After installation, the Buyer reserves the right to demonstrate the ability of the axial ID fanto meet the vibration limits indicating satisfactory performance outlined in ISO-3945-1977.

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