USACE / NAVFAC / AFCESA / NASA UFGS-23 51 43.02 20 (April 2006)
------------------------------
Preparing Activity: NAVFAC Replacing without change
UFGS-15862N (September 1999)
UNIFIED FACILITIES GUIDE SPECIFICATIONS
References are in agreement with UMRL dated January 2009
SECTION 23 51 43.02 20
ELECTROSTATIC DUST COLLECTOR OF FLUE GAS PARTICULATES
04/06
NOTE: This guide specification covers the requirements for furnishing, installing,
adjusting, and testing of electrostatic precipitator(s).
Edit this guide specification for project specific requirements by adding, deleting,
or revising text. For bracketed items, choose applicable items(s) or insert
appropriate information.
Remove information and requirements not required in respective project, whether
or not brackets are present.
Comments and suggestions on this guide specification are welcome and should
be directed to the technical proponent of the specification. A listing of technical
proponents, including their organization designation and telephone number, is
on the Internet.
Recommended changes to a UFGS should be submitted as a Criteria Change Request
(CCR).
NOTE: The precipitator(s) is intended to be used for flue gas particulate removal
and collection associated with coal-fired boilers and refuse-fired waste disposal
incinerators. Coal-fired boilers applicable to this specification are those
designed with capacities ranging between 3.78 and 31.5 kilogram of steam per
second 30,000 and 250,000 pounds of steam per hour. The incinerators applicable
to this specification are those designed for burning municipal-type waste having
firing capacities between 454 kilogram per hour 1,000 pounds per hour and 182
Mg 200 tons per day. For engineering and design assistance on precipitators
applied close to or outside these capacities, contact:
Commanding Officer (ESC Code 433)
NAVFAC Engineering Service Center
560 Center Drive
Port Hueneme, CA 93043-4340
Telephone: (805) 982-4984
There are probably no precipitator manufacturers that can meet all the specifications.
Discretion must be exercised to determine which deviations are acceptable.
PART 1 GENERAL
1.1 REFERENCES
NOTE: This paragraph is used to list the publications cited in the text of
the guide specification. The publications are referred to in the text by basic
designation only and listed in this paragraph by organization, designation,
date, and title.
Use the Reference Wizard's Check Reference feature when you add a RID outside
of the Section's Reference Article to automatically place the reference in the
Reference Article. Also use the Reference Wizard's Check Reference feature
to update the issue dates.
References not used in the text will automatically be deleted from this section
of the project specification when you choose to reconcile references in the
publish print process.
The publications listed below form a part of this specification to the extent referenced. The publications are
referred to within the text by the basic designation only.
[AMERICAN INSTITUTE OF STEEL CONSTRUCTION (AISC)AISC 360(2005) Specification for Structural Steel Buildings, with Commentary][AMERICAN WELDING SOCIETY (AWS)AWS D1.1/D1.1M(2008) Structural Welding Code - Steel][ASTM INTERNATIONAL (ASTM)ASTM A 123/A 123M(2008) Standard Specification for Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel ProductsASTM A 242/A 242M(2004e1) Standard Specification for High-Strength Low-Alloy Structural SteelASTM A 276(2008a) Standard Specification for Stainless Steel Bars and ShapesASTM A 325(2007a) Standard Specification for Structural Bolts, Steel, Heat Treated, 120/105 ksi Minimum Tensile StrengthASTM A 325M(2008) Standard Specification for Structural Bolts, Steel, Heat Treated, 830 Mpa Minimum Tensile Strength (Metric)ASTM A 36/A 36M(2008) Standard Specification for Carbon Structural SteelASTM A 490(2008a) Standard Specification for Structural Bolts, Alloy Steel, Heat Treated, 150 ksi Minimum Tensile StrengthASTM A 490M(2004ae1) Standard Specification for High-Strength Steel Bolts, Classes 10.9 and 10.9.3, for Structural Steel Joints (Metric)ASTM A 580/A 580M(2008) Standard Specification for Stainless Steel WireASTM B 209(2007) Standard Specification for Aluminum and Aluminum-Alloy Sheet and PlateASTM B 209M(2007) Standard Specification for Aluminum and Aluminum-Alloy Sheet and Plate (Metric)ASTM C 533(2007) Standard Specification for Calcium Silicate Block and Pipe Thermal InsulationASTM C 592(2008a) Standard Specification for Mineral Fiber Blanket Insulation and Blanket-Type Pipe Insulation (Metal-Mesh Covered) (Industrial Type)ASTM C 612(2004e1) Mineral Fiber Block and Board Thermal InsulationASTM D 877(2002; R 2007) Standard Test Method for Dielectric Breakdown Voltage of Insulating Liquids Using Disk ElectrodesASTM D 923(2007) Standard Practice for Sampling Electrical Insulating Liquids][INSTITUTE OF CLEAN AIR COMPANIES (ICAC)ICAC EP-1(2000) Terminology for Electrostatic PrecipitatorsICAC EP-10(1995) Bid Specification Information Requirements and Bid Evaluation Form for Electrostatic PrecipitatorsICAC EP-6(1968) Pilot Electrostatic PrecipitatorsICAC EP-7(2004) Electrostatic Precipitator Gas Flow Model StudiesICAC EP-8(1993) Structural Design Criteria for Electrostatic Precipitator Casings][INTERNATIONAL ELECTROTECHNICAL COMMISSION (IEC)IEC 60309-3Pin and Sleeve Devices][NATIONAL ELECTRICAL MANUFACTURERS ASSOCIATION (NEMA)NEMA ICS 1(2000; R 2005; R 2008) Standard for Industrial Control and Systems General RequirementsNEMA ICS 2(2000; Errata 2002; R 2005; Errata 2006) Standard for Industrial Control and Systems: Controllers, Contractors, and Overload Relays Rated Not More than 2000 Volts AC or 750 Volts DC: Part 8 - Disconnect Devices for Use in Industrial Control EquipmentNEMA ICS 6(1993; R 2006) Standard for Industrial Controls and Systems Enclosures][NATIONAL FIRE PROTECTION ASSOCIATION (NFPA)NFPA 70(2007; AMD 1 2008) National Electrical Code - 2008 Edition][SHEET METAL AND AIR CONDITIONING CONTRACTORS' NATIONAL ASSOCIATION (SMACNA)SMACNA 1793(2006) Architectural Sheet Metal Manual, Sixth Edition, Second Printing][THE SOCIETY FOR PROTECTIVE COATINGS (SSPC)SSPC PS 12.01(2002; E 2004) One-Coat Zinc-Rich Painting SystemSSPC SP 1(1982; E 2004) Solvent CleaningSSPC SP 6(7) Commercial Blast Cleaning][U.S. NATIONAL ARCHIVES AND RECORDS ADMINISTRATION (NARA)40 CFR 60Standards of Performance for New Stationary Sources]1.2 DEFINITIONS
Electrostatic precipitator terminology shall be in accordance with ICAC EP-1 except for the following:
a. Aspect Ratio: Effective treatment length divided by effective collection plate height.
b. Collection Surface Area: Area of vertical grounded plates parallel to the gas flow. The
area of components in walkways, hoppers, discharge electrical surfaces, inlet plenums, and outlet
plenums shall be excluded. Exclude area of plates above or below the uniform gas flow.
c. Effective Collection Plate Height: Vertical height of the grounded collection plate in
contact with the flue gas.
d. Effective Treatment Length: Horizontal length of the grounded collection plates parallel
to the gas flow in a single passage in the direction of gas flow. Exclude walkways, inlet plenums,
and outlet plenums.
e. Specific Collection Area: Total grounded collection surface area, in square meter feet,
divided by maximum gas flow rate.
f. Rigid Frame Type: Typical design in which the discharge electrodes are fastened in a support
frame of welded horizontal and vertical masts suspended from four support insulators.
g. Hot Roof: Top section of the precipitator casing between the penthouse and the gas stream.
h. Penthouse Roof: The walking surface on top of the penthouse; that is, the raised pattern
plate that covers the top of the penthouse casing insulation.
i. Plate Spacing: Center to center spacing of the grounded collecting electrode surfaces.
1.3 DESCRIPTION
NOTE:
1. If fly ash conditioning or removal prior to the precipitator is included
in the design, the system should be described.
2. If it is anticipated that the efficiency of the precipitator will be increased
by the addition of field(s) in the future, this should be described.
3. If it is desired that the inlet and outlet breeching be furnished and/or
designed by the collector manufacturer, it should be described.
4. Specify the ESP location and breeching tie points.
Provide electrostatic precipitator(s) of the rigid frame type designed in accordance with ICAC EP-1, ICAC EP-10
, ICAC EP-10, ICAC EP-6, ICAC EP-7, and ICAC EP-8 to remove fly ash from flue gas produced by a [pulverized coal-fired
boiler] [spreader stoker-fired boiler] [underfeed stoker-fired boiler] [refuse-fired waste disposal incinerator].
Provide precipitator(s) suitable for [indoor] [outdoor] installation. Locate the precipitator(s) in the flue
gas system between the [_____] and the [_____].
1.3.1 Electrostatic Dust Collector Layout and Component Drawings
Drawings shall indicate the kind, size, arrangement, weight of each component, and breakdown for shipment; the
external connections, location of local controls, remote control panels, anchorages, and supports required; the
dimensions needed for installation and correlation with other materials and equipment; seismic structural calculations;
and foundation and loading information. Supply drawings for each component showing design and assembly. Provide
schematics of all electrical and pneumatic circuits used. Submission shall include, but shall not be limited
to the following details:
a. Transformer-rectifier equipment.
b. High voltage switches and disconnects.
c. High voltage fuses and circuit breakers.
d. Control systems.
e. Ground lugs.
f. Protection against electrolysis.
g. Graphic display panel indicating power components.
h. Lubrication locations.
i. Electrodes and collecting surfaces.
j. Platforms, walkways, stairways, and ladders which will be required for operation, inspection,
testing, and maintenance, and furnished with the precipitator.
k. Location of field welds, in conformance to AWS D1.1/D1.1M.
1.3.2 Hopper Heater Drawings
Provide layout drawings, wiring diagrams, and control schematics diagrams. Layout drawings shall show each hopper
face including control zones.
1.3.3 Dust Collection System
Submit a full description of the system proposed, including arrangement, operation, and maintenance of the discharge
electrodes and collecting surfaces. Indicate planned rapping cycle and performance test details and sampling
location. Describe electrodes and collecting surfaces.
1.4 PERFORMANCE
NOTE:
1. Select either a collection efficiency or outlet dust loading condition,
whichever is more stringent.
2. The stack emission or efficiency requirements must comply with (a) weight
emission standards; (b) opacity regulations; and (c) community standards for
visible emissions. Compliance with existing emission codes may not satisfy
the opacity regulation. Similarly, opacity regulations may not be as demanding
as community standards. A specific quantitative emission rate must be selected
on the basis of the goals established.
3. Stack opacity is influenced by particle size makeup. For example, with
pulverized coal-fired boilers, about 45 percent of the ash particles are below
10 microns in size; for a cyclone-fired boiler, about 70 percent are below 10
microns; for a stoker-fired boiler, about 25 percent are below 10 microns.
A visually acceptable stack for these three options might require residuals
of 0.046 g/m3 0.02 gr per acf, 0.023 g/m3 0.01 gr per acf, and 0.092 g/m3 0.04
gr per acf, respectively.
4. If it is determined that a spare or additional precipitator section is desirable
to increase reliability, the specification should be modified so that the performance
can be met with any one section out of service.
The precipitator shall operate at a [dust collection efficiency of not less than [_____] percent] [dust loading
at the precipitator outlet of not more than [_____] grams per liter grains per standard cubic foot], as measured
using EPA method 5, when operating continuously at the maximum continuous rating of flue gas flow conditions
and dust loading specified in paragraph entitled "Inlet Gas Conditions." The collection efficiency shall not
be limited because of variations in dust resistivity levels. Flue gas conditioning by injection of sulfur-trioxide,
ammonia, or other substance shall not be an acceptable method of achieving performance.
1.5 OPERATING EXPERIENCE REQUIREMENTS
1.5.1 Equipment
Provide dust collectors which meets all of the operating experience requirements listed below.
1.5.2 Experience Required
NOTE: Allow only operating experience treating flue gas from the equipment
specified in paragraph entitled "Design Criteria" and of the approximate L/s
acfm, temperature and inlet grain loading as that specified in paragraph entitled
"Inlet Gas Conditions."
The manufacturer has constructed not less than three electrostatic precipitators each at a separate facility,
treating flue gas from [a refuse-fired waste disposal incinerator] [a coal-fired boiler] with [automatic] [manual]
combustion control. Each precipitator shall have performed satisfactorily, normal maintenance or downtime of
the associated [boiler] [incinerator] [dust collector] included, for a period of not less than 2 years treating
at least [_____] L/s acfm of inlet gas at a temperature of at least [_____] degrees C F, with inlet dust loading
of at least [_____] grams per liter grains per acf and outlet dust loading of at most [_____] grams per liter
grains per acf.
1.5.3 List of Prior Installations Contents
Submit a certificate from the manufacturer containing the information outlined below within 30 days after award
and prior to commencement of installation. Information to be contained in the certificate shall include:
a. A list of at least three installations at separate facilities meeting the requirements set
forth above.
b. Owner, location, point of contact, and phone number of each such installation.
c. Date of owner acceptance of each such installation.
d. Design inlet gas volume, L/s acfm; inlet gas temperature, degrees C F; inlet dust loading,
grams per liters grains per acf; and outlet dust loading, grams per liter grains per acf.
e. Type of [coal-fired boiler] [refuse-fired waste disposal incinerator].
1.6 MODEL TEST
NOTE: Generally, the complete gas system is included in the model test.
The precipitator manufacturer or a Contracting Officer approved independent modeling and testing lab shall perform
a three dimensional model test of not less than 1:100 1/8 scale. Hold all model dimensions to within plus or
minus 1.50 mm 1/16 inch. The precipitator manufacturer or testing lab shall have at least five years experience
in conducting electrostatic precipitator model tests. (The five years of experience is required prior to proposal
submittal.) The test shall determine the gas flow patterns in accordance with ICAC EP-7procedures, the potential
areas of dust accumulation using sifted bleached wheat flour and neutral buoyancy bubbles, velocity distribution,
and potential pressure drop reductions through the precipitator, nozzles, and breeching. Model breeching and
particulate control equipment from [_____] to [_____]. Include precipitator hoppers, collection plates, distribution
devices, turning vanes, anti-sneak baffles and internal bracing and supports. Simulate the cyclones to represent
the adversely affected gas flow distribution from the cyclones. Perform flow and dust distribution tests at
30, 50, 75, 100, and 125 percent of maximum continuous flow rating. Notify the Contracting Officer of test dates
in writing not less than 14 calendar days before tests are to begin.
1.6.1 Precipitator Model Tests Reports
NOTE: Include other test locations of concern based on the preliminary breeching
design. These may include inlets to induced draft fans and stacks as well as
bypass breeching.
Complete model testing and have approved by the Contracting Officer prior to submittal of drawings. Provide
reports within 30 days of test completion. Include a scale drawing of the model showing actual dimensions and
a scale drawing of the full-size installation showing modifications made and devices added to the breeching and
transitions as a result of the model study. Include uniform gas velocity diagrams and histograms, indicating
the root mean square velocity deviation, standard deviation, and mean velocity, at strategic locations which
shall include, but not be limited to, the following:
a. Inlet to electrostatic precipitator.
b. Outlet of electrostatic precipitator.
Provide a complete explanation of the test procedures including flow rates, pressures, sample calculations and
assumptions prior to testing. List and justify deviations in dynamic or geometric similitude by the model from
the full-size installation. The test report shall recommend breeching configuration changes, gas flow vaning,
straightening or other gas distribution devices in the system required to meet ICAC EP-7 requirements and gas
distribution specified in paragraph entitled "Gas Distribution Devices." Incorporate devices required for specified
gas distribution and modifications necessary to the proposed breeching, that result from model testing, into
the final breeching design. Recommend the location of test ports, the location and type of flow distribution
devices in stack, and the location of gas flow instrumentation points and monitors. Provide a complete listing
of pressure drop data taken at each pressure tap during each test run and also include data from runs before
and after the addition of supplemental flow distribution devices that correct distribution problems identified
by initial runs. Locate pressure tap as required to accurately determine the pressure drop across critical breeching
components and the effect of the additional distribution devices on the pressure drop. Submit with the report
a complete set of photographs and videotape recordings of model during air flow test.
1.6.2 Reports
For precipitator inspection, submit report of the factory service engineer's inspection within 15 calendar days
after the inspection stating his findings including the acceptability of the precipitator for field performance
tests. Submit air load test report with the precipitator inspection report. With performance test reports,
certify that instruments were calibrated and readings indicated are true. Include certification that computations
required for testing are accurate, that acceptable methods were used, and that the equipment performed in accordance
with the requirements. For precipitator calibration, include certification that computations required for testing
are accurate, and that acceptable methods were used.
1.7 SUBMITTALS
NOTE: Review submittal description (SD) definitions in Section 01 33 00 SUBMITTAL
PROCEDURES and edit the following list to reflect only the submittals required
for the project. Submittals should be kept to the minimum required for adequate
quality control.
A “G” following a submittal item indicates that the submittal requires Government
approval. Some submittals are already marked with a “G”. Only delete an existing
“G” if the submittal item is not complex and can be reviewed through the Contractor’s
Quality Control system. Only add a “G” if the submittal is sufficiently important
or complex in context of the project.
For submittals requiring Government approval on Army projects, a code of up
to three characters within the submittal tags may be used following the "G"
designation to indicate the approving authority. Codes for Army projects using
the Resident Management System (RMS) are: "AE" for Architect-Engineer; "DO"
for District Office (Engineering Division or other organization in the District
Office); "AO" for Area Office; "RO" for Resident Office; and "PO" for Project
Office. Codes following the "G" typically are not used for Navy, Air Force,
and NASA projects.
Choose the first bracketed item for Navy, Air Force and NASA projects, or choose
the second bracketed item for Army projects.
Government approval is required for submittals with a "G" designation; submittals not having a "G" designation
are [for Contractor Quality Control approval.][for information only. When used, a designation following the
"G" designation identifies the office that will review the submittal for the Government.] The following shall
be submitted in accordance with Section 01 33 00 SUBMITTAL PROCEDURES:
SD-02 Shop Drawings
Electrostatic dust collector
Hopper heater
SD-03 Product Data
Warning signs
SD-05 Design Data
Dust collection system
SD-06 Test Reports
Precipitator model tests
Hopper heater module voltage tests
Precipitator inspection
Air load test
Performance tests
Precipitator calibration
SD-07 Certificates
List of prior installations
SD-10 Operation and Maintenance Data
Electrostatic dust collector system, Data Package 3
Submit in accordance with Section 01 78 23 OPERATION AND MAINTENANCE DATA.
1.8 DELIVERY AND STORAGE
Ship equipment completely factory assembled, except when the physical size, arrangement, or configuration of
the equipment, or shipping limitations, makes the shipment of completely assembled equipment impracticable, in
which case assemble the equipment and ship as stated in the Contractor's proposal. Provide storage and protection
of delivered equipment in accordance with manufacturer's recommendations.
1.9 DESIGN CRITERIA
[1.9.1 Boiler Data
NOTE: Select the applicable paragraph(s) from the following:
NOTE: Include ash analysis if available. Specify range of properties for coal.
NOTE: Insert appropriate Section number and title in the blanks below using
format per UFC 1-300-02.
Provide electrostatic precipitator(s) for operation with [the boiler(s) specified in [_____]] [boiler(s) manufactured
by [_____], Type [_____], Model No. [_____]]. The boiler is a [new] [existing] [pulverized coal-fired] [spreader
stoker-fired] [underfeed stoker-fired] boiler rated [_____] kilogram per second pounds per hour of steam at [_____]
kPa psi, having a gross heat input of [_____] kilowatt millions Btu per hour, and utilizing coal with the following
properties:
a. Proximate analysis, as received, percent by weight:
Range
Moisture [_____]
Ash [_____]
Volatile Matter [_____]
Fixed Carbon [_____]
Sulfur [_____]
Heating Value, Btu per pound [_____]
b. Ultimate analysis, as received, percent by weight:
Range
Moisture [_____]
Carbon [_____]
Hydrogen [_____]
Sulfur [_____]
Nitrogen [_____]
Oxygen [_____]
Ash [_____]
The expected range of boiler steam output will be between [_____] and [_____] kilogram per second pounds per
hour. Boiler combustion is controlled [manually] [automatically]. The standby fuel is [_____].]
[Incinerator Data
NOTE: The standard classifications of wastes are as follows:
Noncom- Mois- Heating
bustible ture Value
Solids Content (Max.
(max. kJ
Percent by (Max. per
Type Description Principle Components Weight) Percent) kg)
0 Trash Highly combustible 5 10 19,805
waste, paper, wood,
cardboard cartons,
including up to 10%
treated paper, plastic
or rubber scrap,
commercial and
industrial sources
1 Rubbish Combustible waste 10 25 15,145
paper, cartons, rags,
wood scraps,
combustible floor
sweepings, domestic,
commercial, and
industrial sources
2 Refuse Rubbish and garbage; 7 50 10,019
residential sources
3 Garbage Animal and vegetable 5 70 5825
waste, restaurants,
hotels, markets; in-
stitutional,
commercial,
and industrial
sources
4 Animal Carcasses, organs, 5 85 2330
solids and solid organic wastes;
organic hospital, laboratory,
wastes abattoirs, animal
pounds, and similar
sources
Loose
Paper - - 23,300
Loose
Wood - - 23,300
Classified Highly-combustible
Material waste, paper, cardboard 16,310
cartons including up - - to
to 10 0690lastics and 23,300
treated paper
Noncom- Mois- Heating
bustible ture Value
Solids Content (Max.
(max. (Btu
Percent by (Max. per
Type Description Principle Components Weight) Percent) lb.)
0 Trash Highly combustible 5 10 8,500
waste, paper, wood,
cardboard cartons,
including up to 10%
treated paper, plastic
or rubber scrap,
commercial and
industrial sources
1 Rubbish Combustible waste 10 25 6,500
paper, cartons, rags,
wood scraps,
combustible floor
sweepings, domestic,
commercial, and
industrial sources
2 Refuse Rubbish and garbage; 7 50 4,300
residential sources
3 Garbage Animal and vegetable 5 70 2,500
waste, restaurants,
hotels, markets; in-
stitutional, commercial,
and industrial sources
4 Animal Carcasses, organs, solid 5 85 1,000
solids and organic wastes; hospital,
organic laboratory, abattoirs,
wastes animal pounds, and
similar sources
Loose
Paper - - 10,000
Loose
Wood - - 10,000
Classified Highly-combustible waste,
Material paper, cardboard cartons - - 7,000
including up to 10% to
plastics and treated 10,000
paper
Include ash analysis if available. Classified material contents description
may change as plastic use increases. Check incinerator Institute of America
for latest information.
NOTE: Insert appropriate Section number and title in the blanks below using
format per UFC 1-300-02.
Provide electrostatic precipitator(s) for operation with [the incinerator(s) specified in [_____]] [incinerator(s)
manufactured by [_____]]. The incinerator is a [new] [existing] installation capable of burning [_____] [kilogram
per secondpounds per hour] [Mgtons per day] of Type [0], [1], [2], [3], [4], [loose paper] [loose wood] [classified
material] wastes. The expected range of incinerator operation will be between [[_____] and [_____]] [kilogram
per secondpounds per hour] [Mgtons per day] of wastes. Incinerator combustion is controlled [manually] [automatically].
The auxiliary fuel is [_____].
]1.9.2 Mechanical Collector Data
NOTE: Use this paragraph only when a combination of mechanical cyclone-type
dust collector and electrostatic precipitator is selected. An assumed efficiency
range of 35 percent to 70 percent is typical. For existing cyclones testing
may be necessary to determine efficiency.
Provide the electrostatic precipitator(s) with [the mechanical cyclone-type dust collector(s) specified in Section
23 51 43.01 20 MECHANICAL CYCLONE DUST COLLECTOR OF FLUE GAS PARTICULATES" [mechanical cyclone-type dust collector(s)
manufactured by [_____], Type [_____], Model No. [_____]].] The mechanical cyclone-type dust collector [is specified
to have] [was designed for] an overall collection efficiency of [_____] percent. The contractor shall assume
that the cyclone may be operating at any point in the efficiency range of [_____] to [_____] percent.
1.9.3 Inlet Gas Conditions
NOTE:
1. To properly apply their equipment, the precipitator manufacturer must know
the expected inlet gas conditions. For new equipment this information can be
best supplied by the boiler manufacturer, incinerator manufacturer, and mechanical
cyclone-type dust collector manufacturer.
2. In determining the inlet gas conditions for existing installations, source
testing should be performed to determine the gas flow and contents. Gas volume
determinations should be made EPA Methods 1-4 in 40 CFR, Part 60, Appendix A.
For particulate size distribution an actual sample should be taken and analyzed
in accordance with ASME PTC 28, "Determining the Properties of Fine Particulate
Matter." For particulate loading only, use EPA Method 5 or 17.
3. For new installations, the inlet gas conditions should be obtained from
the manufacturer. If this is not possible, the gas contents must be estimated.
When estimates are made, the emission factors and handbook data should be taken
from U.S. Environmental Protection Agency Publication no. AP-42, entitled "Compilation
of Air Pollutant Emission Factors," with the latest supplements. Correction
for expected combustible content should be made. Source testing should be conducted
in accordance with the applicable portion of EPA 40 CFR 60, Appendix A or applicable
local standard.
NOTE: Supply excess air percentage for incinerator applications.
Provide electrostatic precipitator(s) for entire operating range of gas conditions from the [boiler(s)] [incinerator(s)]
[mechanical cyclone-type dust collector] specified above. The electrostatic precipitator inlet gas conditions
shall be:
Maximum Minimum Peak
a. Inlet gas volume, L/s [_____] [_____] [_____]
b. Inlet gas temperature,
degrees C [_____] [_____] [_____]
c. Inlet gas density,
kg per cubic meter [_____] [_____] [_____]
d. Inlet gas moisture,
percent by weight [_____] [_____] [_____]
e. Inlet dust loading,
grams per liter [_____] [_____] [_____]
f. Altitude above sea level,
meter [_____]
g. Particle size distribution:
Maximum Percent by Weight
Size, Microns Less Than Particle Size
60 [_____]
40 [_____]
30 [_____]
20 [_____]
15 [_____]
10 [_____]
7.5 [_____]
1.0 [_____]
Maximum Minimum
h. Fly ash density, for
hopper volume design,
kg per cubic meter [_____] [_____]
i. Fly ash density for weight
determination, kg per cubic
meter (compacted) [_____] [_____]
j. Excess Air (range) [_____] [_____]
Maximum Minimum Peak
a. Inlet gas volume, acfm [_____] [_____] [_____]
b. Inlet gas temperature,
degrees F [_____] [_____] [_____]
c. Inlet gas density,
pounds per acf [_____] [_____] [_____]
d. Inlet gas moisture,
percent by weight [_____] [_____] [_____]
e. Inlet dust loading,
grains per acf [_____] [_____] [_____]
f. Altitude above sea level,
ft [_____]
g. Particle size distribution:
Maximum Percent by Weight
Size, Microns Less Than Particle Size
60 [_____]
40 [_____]
30 [_____]
20 [_____]
15 [_____]
10 [_____]
7.5 [_____]
1.0 [_____]
Maximum Minimum
h. Fly ash density, for
hopper volume design,
pounds per cubic foot [_____] [_____]
i. Fly ash density for weight
determination, pounds per
cubic foot (compacted) [_____] [_____]
j. Excess Air (range) [_____] [_____]
Verify data in the field and design the precipitator(s) to operate efficiently over the entire range of inlet
gas conditions.
1.9.4 Precipitator Data
NOTE:
1. If a spare or additional precipitator section is included, the following
should be added to the collection efficiency: "with one section out of service."
2. As a general rule, use four fields.
3. Usually a minimum of two electrically isolatable bus section per field is
used.
4. Maximum velocity through precipitator is in the range of 1.22-2.13 m/s 4-7
fps.
5. Minimum specific collecting area is in the range of 69 to 98 square meter
per 1000 L/s 350 to 500 square feet per 1000 acfm.
6. Minimum aspect ratio should be at least 1.5.
7. Minimum hopper storage should be at least 12 hours.
8. Usually a 55 degree hopper valley angle is used. If the ash is "sticky"
as for western coal, or if moisture content is high, a 65 degree angle should
be used.
9. Minimum casing design pressure and vacuum is usually 3735 Pa 15 inches WC
.
10. Minimum design for dust on plates should be based on 6 mm 1/4 inch of dust
on all internal surfaces assuming a dust weight of 640-1600 kg/m3 40-100 lb/ft
3.
Apply the following construction criteria to each of the electrostaticprecipitator(s). Base applicable criteria
on flow conditions at maximum continuous rating specified in paragraph entitled "Inlet Gas Conditions."
a. Minimum required collection efficiency, percent [_____]
b. Minimum number of fields in direction of gas flow [_____]
c. Minimum effective treatment time, seconds [_____]
d. Minimum effective treatment length, meter feet [_____]
e. Minimum number of electrically isolatable bus sections per mechanical field [_____]
f. Maximum collection area per electrically separate bus sections, square meter feet [_____]
g. Maximum number of electrically separate bus sections per transformer-rectifier [_____]
h. Maximum number of gas passages per bus section [_____]
i. Minimum number of transformer-rectifier sets per mechanical field [_____]
j. Gas velocity minimum through precipitator, m/s fps[_____]
k. Minimum specific collecting area, square meter per 305 cubic meter feet per 1000 acfm [_____]
l. Maximum vertical height of discharge electrodes, meter feet[_____]
m. Maximum vertical height of collecting electrodes, meter feet [_____]
n. Range of plate spacing, mm inches [_____] to [_____]
o. Minimum discharge electrode cross-sectional area, square mm inches [_____]
p. Maximum horizontal length of each electrical field, meter feet [_____]
q. Minimum aspect ratio [_____]
r. Maximum pressure from [_____] to [_____] Pa inches watergage [_____]
s. Minimum hopper storage capacity, each hopper, hours [_____]
t. Minimum hopper storage capacity, each hopper, cubic meter feet [_____]
u. Minimum hopper valley angle, degrees from horizontal [_____]
v. Minimum number of hoppers for each electrical field [_____]
w. Minimum casing design pressure at [_____] degrees C F, Pa inches water gage [_____]
x. Minimum casing design vacuum at [_____] degrees C F, Pa inches Hg [_____]
y. Minimum casing design temperature, degrees C F [_____]
z. Minimum insulator design temperature, degrees C F [_____]
aa. Minimum design wind load, kg per square meter pounds per square foot [_____]
ab. Minimum design snow load, kg per square meter pounds per square foot [_____]
ac. Minimum design live load, kg per square meter pounds per square foot [_____]
ad. Minimum design load for dust on internal surfaces, kg pounds [_____]
1.9.5 Breeching
Provide breeching, stiffeners, bracing, supports, hangers, supporting steel, expansion joints and heat insulation
between the [_____] and [_____]. Design the breeching to withstand internal pressures between plus 3735 to minus
6225 Pa 15 to minus 25 inch water gage. Include turning vanes in breeching as recommended by the report on model
test. Provide self-cleaning type breeching to prevent dust accumulation. Provide expansion joints to give the
breeching sufficient flexibility under thermal changes. Provide suitable supports and guides to eliminate transverse
loading of flexible expansion joints.
1.9.6 Coordination
Coordinate design parameters and controls of precipitator between precipitator manufacturer and manufacturers
of equipment which will interface with, or affect, system operation. Design the precipitator for operation with
the [boiler] [incinerator] [and the mechanical cyclone type dust collection] specified to assure that the collection
efficiency specified is attained.
1.9.7 Electrostatic Dust Collector System
Submit operation and maintenance data for electrostatic dust collector system in accordance with Section
01 78 23 OPERATION AND MAINTENANCE DATA.
1.10 AMBIENT ENVIRONMENT IN VICINITY OF ELECTRICAL EQUIPMENT
Guarantee that electrical equipment mounted external to the precipitator housing shall perform satisfactorily
during normal operation of the [boiler] [incinerator] at loads within its rated limits and during start-up and
shutdown, with an ambient environment of [[_____] to [_____]] degrees C F and [[_____] to [_____]] percent relative
humidity, and exposure, including solar effects. Electrical equipment shall include the following:
a. Motors, motor starters, controllers, and controls
b. Transformer-rectifiers
c. Rapper coils
d. Insulators
e. High voltage bus
f. Raceway and conductors interconnecting precipitator electrical equipment
g. Pressure switches
h. Heater contactors.
1.11 MISCELLANEOUS
Provide installation complete in accordance with this specification and as shown and include the following:
a. Wiring, conduits, fittings, supports, and grounding of electrical equipment in accordance
with Division 16, "Electrical."
b. Special tools and devices required for operating, adjusting, repairing, and maintaining
the air pollution control with their accessories.
c. Warning signs, of an approved permanent type, where required for the safety of operating
personnel.
d. Bronze grounding lugs outside each access door into the precipitator.
1.12 DELIVERY OF MODEL
The model used for testing shall remain the property of the Government. Deliver the model including a support
table to the Contracting Officer within six months after Government acceptance of the full size units.
PART 2 PRODUCTS
2.1 MATERIALS
Parts exposed to the flue gas of materials having physical suitable for the service and able to withstand the
abrasive and chemical action of the flue gas and fly ash. Make parts subject to deterioration easily accessible
for inspection, maintenance, or replacement. The materials used shall conform to the following:
NOTE: Use ASTM A 242/A 242M steel when material is subjected to continuous
temperatures of 204 degrees C 400 degrees F or higher.
a. Housing plate and stiffeners: [ASTM A 242/A 242M, Type 1]
NOTE: Use ASTM A 242/A 242M steel when material is subjected to continuous
temperatures of 204 degrees C 400 degrees F or higher.
b. Hoppers: [ASTM A 242/A 242M, Type 1] [ASTM A 276]
NOTE: Use ASTM A 242/A 242M steel when material is subjected to continuous
temperatures of 204 degrees C 400 degrees F or higher.
c. Discharge electrodes: [ASTM A 242/A 242M, Type 1]
NOTE: Use ASTM A 242/A 242M steel when material is subjected to continuous
temperatures of 204 degrees C 400 degrees F or higher.
d. Collecting surfaces: [ASTM A 242/A 242M, Type 1]
NOTE: Use ASTM A 242/A 242M steel when material is subjected to continuous
temperatures of 204 degrees C 400 degrees F or higher.
e. Gas distribution devices: [ASTM A 242/A 242M, Type 1]
NOTE: Use ASTM A 242/A 242M steel when material is subjected to continuous
temperatures of 204 degrees C 400 degrees F or higher.
f. Structural and miscellaneous steel: [ASTM A 242/A 242M, Type 1]
2.2 STRUCTURAL SUPPORTS
NOTE: Use 6 mm 1/4 inch thick steel for temperatures over 260 degrees C 500
degrees F. Detail structural supports on drawings.
Provide steel support structures for the precipitator as [indicated] [specified herein]. Provide the precipitator
with column extensions or stubs to project from the precipitator internal support system to the support structure.
Provide column extensions or stubs of adequate length to provide clearance between the precipitator casing and
hoppers and the support frame beams. Provide sufficient clearance to permit the insulation and casing to be
installed and to accommodate the extremes of displacement caused by thermal expansion. Support precipitator
components from the precipitator internal support system. Provide additional grid steel required at the unit
for support of precipitator components. Anchor the precipitator on its centerlines and allow to expand in both
directions. Provide slide plates for installation between the precipitator free support points and the support
structure. [Design the precipitator supports for seismic probability zone [3][4] in accordance with Section
22 05 48.00 20 MECHANICAL SOUND VIBRATION AND SEISMIC CONTROL.] Fabrication and erection of structural steel
shall conform to AISC 360.
2.3 ELECTRICAL REQUIREMENTS
2.3.1 Electrical Scope of Work
The work covered by this section consists of providing, adjusting, testing, and placing in operation electrical
equipment and materials which are an integral part of the electrostatic precipitator provided under this section.
2.3.1.1 Material and Workmanship
Material and workmanship in factory assembled equipment, unless indicated or specified otherwise, shall conform
to Division 16, "Electrical." Include interconnecting conduit and wire, grounding, and the electrical connection
of the mechanical equipment to the electrical power circuit under Division 16, "Electrical."
2.3.1.2 Electrical Supply Voltage
Provide supply voltage of [_____] volt, three phase and [_____] volt, single phase, 60 hertz. Balance single
phase loads on three phase systems. Except as specified herein, design all equipment for energization from a
[_____] volt, single phase, 60 hertz electrical supply.
2.3.1.3 Transformers
Supply transformers and accessory equipment as required to convert the [[_____] volt, three phase] [[_____] volt,
single phase], 60 hertz electrical supply to those voltages required.
2.3.2 Equipment Enclosure Heaters
Provide outdoor equipment enclosures with space heaters to prevent condensation of moisture within the equipment
enclosures. Space the heaters away and thermally insulate from close painted surfaces. Control the heaters
by an adjustable thermostat set to deenergize the heaters when the temperature rises to 35 degrees C 95 degrees
F, and to energize the heaters when the temperature decreases to 29 degrees C 85 degrees F. The space heaters
shall not interfere with normal entrance of cables into the enclosures or equipment within the enclosure.
2.3.2.1 Equipment Enclosure Nameplates
Provide equipment enclosures and associated switches, indicating lights, meters, and devices with nameplates.
2.3.2.2 Equipment Enclosure Grounding
Provide equipment enclosures with a ground bus and connectors in accordance with National Electrical Code. Connect
electrical equipment to the grounding system specified in Division 16, "Electrical."
2.3.2.3 Insulation and Weatherproofing
NOTE: Use this paragraph only when equipment is exposed to the atmosphere.
Insulate and weatherproof electrical enclosures exposed to the atmosphere. The enclosures shall conform to specification
for insulation and enclosure for roof housing in paragraph entitled "Housing."
2.3.2.4 Wiring
Wiring design and installation shall be in accordance with NFPA 70 and as specified.
2.3.3 Transformer-Rectifier (T-R) Set
NOTE: T-R voltage should be 50 KV DC average as a minimum. Sump must be covered
and piped to an oil-water separator if penthouse is not covered by a weather
enclosure.
Enclose the high voltage rectifying equipment in the sealed transformer case to form a single enclosure. The
enclosure shall meet the requirements of NEMA Type 3R construction as described in NEMA ICS 6. Provide oil-filled,
air-cooled type transformer designed and shielded for precipitator service. Equip the transformer case with,
at a minimum, the following items: connection box, grounding connection, filling connection, drain and sampling
valves, thermometer, oil and vacuum gages, and high temperature alarm. Provide sump to contain the oil which
may leak from the transformer. Provide rectifier with concentric pipe and guard conductors between power supply
and precipitator. Voltage supply shall be rated for [_____] volts. T-R capacity shall be [_____] KVA maximum.
T-R output voltage rating shall be [_____] kV minimum. T-R shall operate at 60 percent to 100 percent of its
current rating at normal operating conditions.
2.3.3.1 Rectifier
Provide oil immersed, solid state silicone type rectifier. Mount within the transformer case and equip with
necessary surge equalizers and suppressors. Arrange interior parts to facilitate circulation of oil for adequate
cooling.
2.3.3.2 Grounding Switches
Provide each transformer-rectifier set with a five-position grounding switch to permit grounding of both bushings;
full-wave power to one bushing, grounding of the other bushing and vice versa; half-wave power to both bushings.
Provide a bus duct between the power supply and the precipitator. Do not connect more than two bus sections
to a single transformer-rectifier set; connect each bus section to a single bushing and connect each bushing
to only one bus section.
2.3.3.3 Transformer Oil
Provide insulating mineral oil, PCB free, kV rated with required dielectric rating. Sample the oil after installation
and test in accordance with ASTM D 923 and ASTM D 877. If the oil does not meet the ASTM specification, dry
and filter until it meets or exceeds the requirements.
2.3.4 Control Cabinet
Provide controls for the high voltage precipitator supply in control cabinets and include all regulating devices.
Provide control cabinets that are completely wired, self-ventilated, free standing, and enclosed in a grounded
casing. Maintain cabinet at positive pressure using a fan powered by a 120 volt, single-phase motor with a power
output of not less than [0.093 kW] [1/8 hp] [_____]. Filter pressurizing air with a filter that is not less
than 98.5 percent efficient for dust particles one micron or larger. Equip control cabinet and T-R with a safety
key interlock. Construct the control cabinet in accordance with NEMA Type 12 as defined in NEMA ICS 6. Each
controller shall conform to NEMA ICS 1 and NEMA ICS 2 and contain, but not be limited to, the following:
a. Completely automatic solid state controller which will maintain a preset spark rate, maximum
current, and maximum voltage; silicon controlled rectifiers driven by transistorized automatic
controls with auxiliary manual capability. Provide the reactor in conjunction with the T-R
set with a nominal impedance of 40 percent and additional taps at 50 percent and 60 percent
impedance. Provide easily accessible taps to facilitate changing of tap position. The reactor
shall hold inductance within 5 percent at 2.5 times rated current at 40 percent impedance.
b. Full range control on both manual and automatic. Field adjustments to the automatic control
shall be maximum current, maximum voltage, and spark rate set point.
c. Indicators, meters, and protection.
d. High voltage start and stop pushbuttons.
e. Thermal line breaker with undervoltage coil and adjustable magnetic trip.
f. Transformer primary AC voltmeter.
g. Transformer primary AC ammeter.
h. Precipitator DC milliammeter.
i. Precipitator DC voltmeter.
j. Precipitator spark rate meter.
k. High temperature alarm indicator for T-R oil temperatures.
l. Auxiliary contacts for the attachment of a partable oscilloscope in order to observe both
voltage and current wave forms on the high tension electrodes.
m. Inverse time over current relay for units rated higher than 300 milliamperes.
n. Static regulator to limit precipitator current during automatic control.
o. Alarm circuit interlock which opens when transformer primary circuit is energized.
p. Fused control disconnect for circuit breaker undervoltage coil and automatic control.
q. Manual automatic control select switch.
r. Thyristors with heat sink sized for operation without thyristor fan.
s. Automatic voltage control unit.
t. Three position selector switch with indicating lights; "LOCAL-MANUAL," "LOCAL-AUTO," and
"REMOTE-AUTO" positions.
u. Adjustable memory.
v. Visual annunicator for each of the following conditions:
(1) T-R overload, one each transformer-rectifier.
(2) T-R undervoltage, one each transformer-rectifier.
(3) T-R high voltage short circuit and open circuit, one each transformer-rectifier.
(4) T-R open circuit, one each transformer-rectifier.
(5) High temperature indicator for T-R oil temperatures.
2.3.4.1 Arc Suppression Within the Precipitator
Controls shall prevent or minimize sparking. The device shall suppress an arc within 1/2 cycle and recover within
two cycles to initial voltage before arc. Recovery rate shall be adjustable.
2.3.4.2 Auxiliary Alarm
Wire the control enclosure so that an isolated contact will close and alarm the local annunciator when any of
the white indicating lights are illuminated for any of the T-R controls specified in paragraph entitled "Control
Cabinet." Similarly provide an isolated contact to close and to alarm the local annunciator when any T-R control
is not in the "REMOVE-AUTO" position.
2.3.4.3 Pushbutton Stations
NOTE: Require these indicator lights if remote indication is required.
Wire the start pushbuttons to function only when the three position selector switch is in the "LOCAL-MANUAL"
or "LOCAL-AUTO" positions. In addition to shutting down the T-R, the stop pushbutton shall clear all alarm outputs,
except the output indicating that T-R control is not remote. Startup, whether by local pushbutton or remote control,
shall arm the alarm system. Provide remote control so that all T-R sets which have their three-position selector
switches in the "REMOTE-AUTO" position may be stopped by pushbutton station on the main control panel. Provide
output contacts for remote indication of the status of T-R which are in the "REMOTE-AUTO" mode. Provide indicating
lights for each precipitator on the auxiliary boiler control panel as follows:
a. Green -- all units off.
b. Red -- all units on.
NOTE: Require amber light if sequential startup is required.
c. Amber - startup in progress.
2.3.4.4 Redundant Protective Devices
Provide redundant protective devices on controller connections to the transformer unit secondary circuit.
2.3.5 High Voltage System Wiring and Support Insulators
NOTE: Use this paragraph for "bus-duct" wiring.
Provide wiring materials and insulators, including insulators for discharge electrode supports, required to electrically
connect the T-R to the discharge electrodes. The high voltage lead from the rectifier to the discharge electrodes
shall consist of a conductor in metal enclosed weatherproof bus duct. Furnish the bus duct complete with necessary
insulators, duct supports and fittings, and supply formed to exact length ready for bolting to the equipment.
2.3.6 High-Voltage Leads
NOTE: Use this paragraph for "pipe" wiring.
Completely enclose high voltage leads to the precipitator in a grounded 16 gage minimum thickness sheet metal
guard. The conductor shall be 20 mm 3/4 inch diameter, Schedule 40 iron pipe. Include equipment for the introduction
of clean purging air in and around the support bushings to prevent dust buildup on the insulators. The high
voltage conductor pipe shall have a union immediately connected to the T-R set so the T-R can be easily isolated
from the precipitator. Connect the conductor pipe to the high voltage electrode frame by a removable wire lead.
2.3.7 High Voltage Insulators
Provide a minimum of four insulating support bushings for each electrical bus section. Compression-load the
high tension insulators and install outside of the contaminated gas stream. Provide insulators of materials
suitable for the temperature. Provide best process electrical glazed ceramic high density 85 percent alumina
for temperatures below 454 degrees C 850 degrees F. Provide adequate access for removal and reinstallation of
high voltage insulators. Provide four pad-eyes above each high voltage bus frame to facilitate lifting of the
frame for precipitator maintenance. Attach pad-eyes to support beams. Each pad-eye and support beam shall be
capable of supporting the entire weight of its respective high voltage bus frame. Provide other means for lifting
high voltage bus frames if acceptable to Contracting Officer.
2.3.8 High Voltage Insulator and Pressurizing System Heaters
Provide a heating and pressurizing/purging system for the high voltage bus duct insulators and the discharge
electrode support insulators. Furnish control devices to automatically energize the heaters, as required, when
the temperature of the insulating support bushings falls below [107 degrees C] [225 degrees F] [_____] and deenergize
the heaters when the temperature reaches [121 degrees C] [250 degrees F] [_____]. The system shall maintain
an insulator temperature of 107 degrees C 225 degrees F when the precipitator is off line. Provide sufficient
pressure to prevent the infiltration of dust and moisture laden air into the penthouse and to keep the inside
of the high voltage insulators free from the flue gas. Supply a minimum of 47.20 L/s 100 acfm of heated, filtered
air for each insulator. Direct the purge air downward in swirl pattern across the inside surface of each insulator.
Provide a purge air filter of the disposable or cleanable type with a filter efficiency of not less than 98.5
percent for dust particles of one micron or larger. Provide remote annunciation for malfunctions of the heating
and pressurizing system as specified in paragraph entitled "Annunication and Indication." Provide pressurizing
fans, complete with electric motor, automatic backflow prevention dampers, inlet filters, and a relief device
for filter bypass in case of blocked filters. Furnish a minimum of two fans for each pressurizing system. Provide
pressurizing fans of equal capacity and requiring the same size motors. Upon less of any one fan, the remaining
fans shall automatically pressurize the system as required to ensure continued normal operation of the precipitator.
Provide a control system consisting of necessary relays, pressure switches, flow switches, and control devices.
Factory mount control devices, except those requiring local mounting, and wire in an indoor NEMA ICS 6, Type
12 floor-mounted control enclosure. Provide each fan discharge duct with an airflow switch for use in fan control.
Furnish locally mounted NEMA ICS 6, Type 4 combination starters for the fans. Mount an "AUTO-ON" selector switch
for each fan on the door of its associated local combination starter. Mount indicating lights for system status
on the starter door. Provide each fan control circuit with a two-position, "AUTO-ON," selector switch. Provide
a single normally open contact, which will close upon start up of the induced draft fans, when the selector switch
is in the "AUTO" position. Provide relays as required to multiply this signal. Electrically isolate output
contacts for controls motor starters.
2.3.9 Discharge Electrodes and Collecting Surfaces
Provide rigid frame type discharge electrodes. Rigid electrode, or weighted wire design precipitators are not
acceptable. The discharge electrodes in each passageway shall run in a vertical direction and shall be supported
by a welded pipe, tube, or channel frame. Provide the frame with vertical pipe, tube, or channel supports spaced
at a maximum interval of 1.22 meters four feet. Also provide the frame with horizontal pipe, tube, or channel
supports spaced at a maximum interval of 1.22 meters four feet. The electrodes shall have a cross-sectional
area of not less than 16 square mm 0.025 square inches and not more than 64.52 square mm 0.10 square inches.
Fabricate collecting surface from rolled seamless sheet of not less than 16 gage thickness. Collecting surface
plate spacing shall be not less than 280 mm 11 inches or greater than 330 mm 13 inches. Support discharge electrodes
and collecting surfaces as required to maintain proper alignment during operation. Support each main discharge
electrode bus section support frame by four alumina support insulators. Design collecting surfaces so that deflection
from a plane surface will not exceed plus or minus 6 mm 1/4 inch about any axis. Design and construct discharge
electrodes and collecting surfaces to be readily located and aligned within plus or minus 6 mm 1/4 inch of the
normal design position. Assemble the collecting surfaces at the factory. Factory assembled modules which can
be shipped to the field for erection may be provided. Provide high voltage frames with sway braces or other
devices as required to prevent swaying. Incorporate gas baffles into the collecting plates to provide a gas flow
quiescent zone and to provide stiffening.
2.3.10 Rappers
Provide falling hammer collecting surface and discharge electrode rappers with individual hammers for each plate
and frame. Design plate rappers for sequential rapping to prevent simultaneous rapping of plates and provide
a minimum of 27 N.m 20 foot pounds of rapping force per plate. Design discharge electrode rappers for sequential
rapping to prevent simultaneous rapping of frames and provide a minimum of 12.24 N.m 9 foot pounds of rapping
force per frame. Provide solid steel rapper drive shafts with a minimum diameter of 50 mm 2 inches. Provide
magnetic impulse gravity return gas distribution plate rappers with individual rappers for each plate or screen.
2.3.10.1 Rapper Controls
Rapper controls shall have adjustments for independent field repeat intervals and for independent field rest
time.
2.3.10.2 Rapper Control System
Provide a rapper control system conforming to NEMA ICS 1 and NEMA ICS 2 consisting of necessary devices for the
complete control of each rapper system. Factory install and wire the system for [indoor] [outdoor] installation
in a NEMA [12] [3R] cabinet as described in NEMA ICS 6 and locate in [control house] [control room] [roof].
Provide outdoor mounted units finish painted for outdoor service, wind braced for [_____] km miles per hour wind
and completely weatherproofed.
2.3.10.3 Rapper Disconnects
Provide disconnecting switches for individual rapper groups to deenergize for servicing.
2.3.10.4 Rapper High Voltage Spikes
Provide the rapper system with surge suppressors and other devices as required to eliminate high voltage spikes.
2.3.10.5 Rapper Annunciation
Provide remote annunciation for malfunctions of the rapping system as follows:
a. "White" light for rappers not operating (power failure).
2.3.11 Annunciation and Indication
2.3.11.1 Off-Limit Conditions
Provide annunciator and indication equipment for individual annunciation and indication of the following off-limit
conditions:
a. T-R control trouble.
b. T-R overload, one each transformer-rectifier.
c. T-R undervoltage, one each transformer-rectifier.
d. T-R open circuit, one each transformer-rectifier.
e. T-R not in remote, one each transformer-rectifier.
f. Penthouse or insulator compartment air pressure low.
g. Loss of penthouse pressurizing airflow.
h. Rapper control failure, one each rapper control enclosure.
i. Low hopper temperature.
j. Insulator temperature below [107 degrees C] [225 degrees F][_____].
k. Purge air filter clogged.
2.3.11.2 Annunciator
Provide annunciator with a station for each alarm input plus a minimum of 25 percent spare stations. Provide
sufficient stations for annunciation such that the items of equipment that failed can be easily identified. Provide
a backlighted window for each station with an engraved legend that will be readable by a [standing] [sitting]
operator at the operating station. The unit shall be complete with test, audible silence, flasher reset, and
lamp reset pushbuttons and audible device. Incorporate an adjustable time delay relay in the annunciator audible
device circuit to cause automatic silencing of the device after a manually selected time period. The annunciator
stations shall, however, remain lighted until the trouble is cleared. Provide solid-state type annunciator,
suitable for 120 volts AC power supply with not less than 125 volts DC applied to the trouble contacts. Include
one electrically isolated contact per window for remote annunciation. Provide positive oriented logic, 120 volts
AC or 125 volts DC power supply for trouble contacts, and two lamps wired in parallel circuit per indicating
window. Design annunciator alarm contacts to accept field contacts which close on alarm condition. Do not use
contacts which open on alarm condition. Provide an auxiliary isolated contact for each station. The auxiliary
contact action shall follow that of the field contact. Provide cover-mounted annunciator, test, audible silence,
flasher reset, lamp reset, and acknowledge pushbuttons on a NEMA ICS 6, Type 12 enclosure. Mount and wire the
following devices inside the enclosure:
a. Annunciator audible device.
b. Fuse and fuse holder for annunciator power supply.
c. Fuse and fuse holder for the audible device.
d. Terminal blocks for connections to all external circuits.
2.3.12 Electrical Service Outlets
Provide a 20 amp, 110 VAC duplex ground fault NEMA 5 20R terminal duplex interrupter receptacle within 2.44 meters
8 feet of access doors except doors in the hot-roof and gas distribution plates. The receptacles on each precipitor
level shall be on a separate circuit. Ground fault interrupters shall test and reset at the receptacle. Wire
receptacles to provide individual receptacle protection such that no other receptacles are interrupted by an
individual receptacle trip. The receptacle shall interrupt at 5 plus or minus 1 milliamp ground fault current.
Provide specification grade or better receptacles and protect by weather tight covers. Provide a CS 6369 (Alpha
Configuration) 50 amp, 3 pole, 4 wire , 120/250 VAC twist type receptacle in a FS box with a weatherproof cover
(Hubbell SR-50 or approved equal - item may be provided as an integral assembly or as individual components)
inside each weather enclosure on separate circuits. Provide a weatherproof 100 amp, 3 pole, 4 wire, 120/250
VAC, pin ad sleeve receptacle conforming to IEC 60309-3 within 15 meters 50 feet of each stack base and each
precipitator base. Provide each of the 50 amp receptacles with an individual 50 amp, 208 VAC service. Provide
each of the 100 amp receptacles with an individual 100 amp 208 VAC service.
2.4 HOUSING
Construct the precipitator housing, including inlet and outlet nozzles, of minimum 6 mm 1/4 inch thick steel
plate and attach to appropriate structural steel supporting members. Plumb the housing within 10 mm 3/8 inch
measured at top, bottom, and tie points, side to side, and front to rear. The top of the precipitator support
shall be flat within 1.50 mm 1/16 inch for area of support foot and at elevation within 3.18 mm 1/8 inch. Make
provisions, including expansion joints if required, to allow for any expansion, differential expansion, and contraction
that may occur. Design the expansion provisions to prevent escape of gas or inflow of ambient air. Provide
a minimum of 1.50 meters 5 feet of vertical clearance inside the housing above the discharge electrodes and collecting
surface frames to afford access for inspection and maintenance. Locate walkways internal to the housing between
electrical fields, at the inlet to the first field, at the outlet to the last field, and as otherwise required
to provide access to equipment located within the housing which may require inspection or maintenance. Provide
access to internal walkways by two access openings located on opposite sides of the precipitator for each internal
walkway. Access openings shall align directly with internal walkways and shall be unobstructed. The walkways
shall provide a minimum passageway clearance of 762 mm 30 inches. Provide the housing with insulated, hinged,
quick opening, access, inspection, and cleanout doors with gastight seals as required for proper operation and
maintenance. Provide a minimum of one door above each bus section. The minimum access opening size shall be
460 by 600 mm 18 by 24 inches for rectangular openings and 600 mm 24 inches diameter for round openings. Provide
key interlocks for openings through which personnel may come in contact with high voltage equipment to prevent
opening before the electrical supply is deenergized. The housing shall be of all welded construction. Minimize
the use of flanged or bolted joints. Use only where bolted assembly is required for adjustment or removal.
Prevent structural members from acting as radiators, thereby reducing internal corrosion. The difference between
the inside wall temperature at any point and the inlet gas temperature shall be less than 22 degrees C 40 degrees
F.
2.4.1 Penthouse
Provide a penthouse to enclose the high voltage system support insulators. Enclose the entire top of the housing.
Design the penthouse to withstand the effects of differential thermal expansion between the precipitator housing
and the penthouse. Design the expansion provisions to assure an airtight penthouse. Weld gas tight. Check
for leaks using smoke candles or other method approved by the Contracting Officer. Repair leaks by welding or
repair of mechanical seals. Do not use caulking. Provide a minimum of 2 insulated, hinged, quick-opening access
doors on the penthouse roof; one at each end of the roof. Provide penetrations, openings and hatches in or on
the penthouse roof with mechanical seals or weld to provide a gas tight and watertight seal. Install calcium
silicate insulation conforming to ASTM C 533 over 12 gage steel pines stud welded on 610 mm 2 foot centers on
the penthouse roof. Hold in place by 65 mm 2 1/2 inch square speed washers and closely fit around penetrations.
Construct top surface of 6 mm 1/4 inch thick raised pattern plate conforming to ASTM A 242/A 242M, Type I to
form a continuous walking surface. Provide support to bear not less than 488 kg per square meter 100 pounds
per square foot live load. Provide additional support for equipment placed on the roof. Seal joints by continuous
fillet or complete penetration groove welds as applicable. Weld appurtenances similarly to the plate. Provide
top penetrations with a 50 mm two inch minimum extension above the plate and similarly weld to the plate. Slope
the top surface to allow water runoff and to prevent pooling. Extend top surface at least 25 mm one inch beyond
side insulation. Provide a 80 mm 3 inch fascia of 6 mm 1/4 inchsteel conforming to ASTM A 242/A 242M plate as
a rain barrier. Provide a 80 mm 3 inch kickplate of 6 mm 1/4 inch steel conforming to ASTM A 242/A 242M plate
around the perimeter of the top surface and provide adequate drain holes to permit water runoff. Provide a safety
rail on the top perimeter. Manufacture top surfaces of appurtenant structures with 6 mm 1/4 inch steel conforming
to ASTM A 242/A 242M raised pattern floor plate in a manner similar to that specified herein including soffit
and fascia dimensions. Aluminum casing materials shall conform to ASTM B 209M ASTM B 209.
2.4.2 Insulation Materials
NOTE: For operating temperature range of 94 to 260 degrees C 201 to 500 degrees
F use minimum thickness of 115 mm 4 1/2 inches. For operating temperatures
261 degrees C 501 degrees F and above use minimum thickness of 140 mm 5 1/2
inches.
Insulate the precipitator housing, penthouse, and hoppers with ASTM C 612 mineral fiber block or ASTM C 592 mineral
fiber blanket insulation. Insulate the roof with ASTM C 533 calcium silicate block. Minimum insulation thicknesses
shall be as follows:
a. Housing [_____] mm inches
b. Hoppers [_____] mm inches
c. Hot Roof [_____] mm inches
d. Penthouse [_____] mm inches.
2.4.3 Casing Materials
Casing except top surface casing, which might serve as personnel walking surface, shall be 1.27 mm 0.050 inch
thick stucco embossed, 100 mm 4 inch rib, unpainted aluminum panel. Aluminum casing shall be ASTM B 209M ASTM B 209
.
2.5 HOPPERS
Construct hopper plate of [Type 316 stainless steel conforming to ASTM A 276] [structural steel conforming to
ASTM A 242/A 242M Type 1] and a minimum 6 mm 1/4 inch thick. Provide hoppers with ASTM A 242/A 242M baffles
to prevent flue gas from bypassing the electrostatic field. Hoppers shall span no more than one electrical field.
Provide hoppers with untapered fillet plates, constructed of cold rolled minimum 10-gage ASTM A 276 Type 316
stainless steel, in each corner. Extend the fillet plates the full length of the corner. Seal weld the fillet
plates to the hopper walls. Provide closure plates at the top of the hopper at each corner to prevent flow into
the area between the fillet plate and the hopper corner. Steel reinforcements not in contact with the gas or
ash may be either ASTM A 276 Type 316 stainless steel or ASTM A 242/A 242M structural steel. If the latter is
used, select welding rods specifically for the service and submit to the Contracting Officer for approval. Provide
protection of rods against moisture.
2.5.1 Hopper Accessories
Provide key interlocked access doors on each hopper on both sides of any hopper baffle. Doors shall be in accordance
with the requirements specified herein. Hoppers shall have adequate flexibility for vibrators. Provide each
hopper with two 100 mm 4 inch poke holes with a tee wash connection and screwed caps. Position poke holes to
permit downward thrusts into the hopper. Provide a special plate reinforced "pounding area" on each hopper face
for external manual vibrating. Each pounding plate shall be 300 by 300 by 25 mm 12 by 12 by 1 inch thick ASTM A 36/A 36M
plate steel. Provide a work platform with stairs to each pounding area for units with pounding areas more than
1.50 meters five feet above ground. Do not insulate pounding plate. Finish insulation at this discontinuity.
Provide a minimum 200 mm 8 inchdiameter flanged fly ash outlet connection on each hopper to accept the fly ash
transportation system equipment. Provide access hatch not less than 200 by 200 mm 8 by 8 inches for cleanout
within 200 mm 8 inches above flange.
2.5.2 Hopper Vibrators
Provide each hopper with two vibrators set at the mid-height and on opposite sides. Interface vibrator controls
with ash collection system to provide automatic vibrator operation only at the inception and during an evacuation
cycle. Provide manual override control for hopper vibrators and evacuation system in hopper area and enclose
in (a) case(s) to prevent accidental energization of systems. Place a warning over the vibrator manual control
with the following inscription:
"WARNING: VIBRATOR CONTROL. DO NOT ACTIVATE UNLESS HOPPER EVACUATION SYSTEM IS OPERATING."
2.5.3 Hopper Heater System
Provide a hopper heater system for each precipitator.
2.5.3.1 Hopper Heater System Design
Provide the system complete with all material required for mounting. The system shall provide a 139 degrees
C 250 degree F rise in temperature in the hopper, in the vicinity of the heaters, during offline and startup
conditions. Size the system to provide a hopper skin temperature of not less than 177 degrees C 350 degree F
when the insulation is in place during minimum ambient temperatures specified in Section 23 07 00 THERMAL INSULATION
FOR MECHANICAL SYSTEMS. Design the system with a minimum heating safety factor of 1.1 and a minimum wind heat
loss factor of 1.12. Design the system to provide maximum heater coverage between hopper stiffeners utilizing
modular heaters and flexible blanket or tape heaters for the hopper throat heating. Heater modules shall cover
not less than 33 percent of the hopper area. Cover the bottom portion of the hopper to the maximum extent possible,
and extend at least 70 percent up the hopper height. Provide a two zone system. Comprise the lower zone of
heaters located on the bottom one-third of hopper height including the throat heater; the upper zone shall include
the remaining hopper heaters. Use flexible electric heating blankets or tapes, capable of withstanding 427 degrees
C 800 degree F, where modular equipment will not fit. Provide only equipment designed to withstand natural and
induced vibrations, plus shock loadings normally experienced during operation of the precipitator and ancillary
equipment including manual rapping of the strike plates. Provide an individually, thermostatically controlled
hopper heater system with adjustable setpoint and include power, control, and alarm components. Locate the low
temperature and control thermocouples in the lower portion of each heater zone. Heater voltage shall be 480
volts AC. Control voltage shall be 120 volts AC.
a. Hopper Heater Module Design: Provide self-contained, modular heaters. Provide hopper heater
modules which have a flexible heating face to conform to the irregularities of the hopper surface,
providing contact between the heaters and the hopper, and providing maximum heat transfer.
Provide low watt density design modules with a maximum of 0.0047 watts per square mm 3 watts
per square inch of resistance element and with a minimum of six parallel resistance paths per
heater. Continuous blanket type elements shall be deemed to meet the multipath requirement.
Each module shall have dual heating elements. Both elements shall function during startup and
offline conditions. To reduce power consumption and cycling while maintaining the hopper temperature
during online operating conditions, controls shall automatically switch off one element in the
lower zone and both elements in the upper zone without affecting the remaining element's operation.
The hopper throat blanket heater shall have a single heating element and shall remain on during
startup, offline, and online operating conditions. Each heating element in the module shall
be capable of being operated at and shall be rated at 2690 watts per square meter 250 watts
per square foot, but shall be designed to operate at 2152 watts per square meter 200 watts per
square foot. Size wiring, circuits, and controls for 2690 watts per square meter 250 watts
per square foot. Total power density shall be not less than 4303 watts per square meter 400
watts per square foot of heater module surface. Construct heating elements of 600 series stainless
steel alloy or ni-chrome encased in a 20 gage minimum thickness aluminum or aluminized-steel
mounting pan or casing. Provide two sets of heater pigtails for each module, one set of pigtails
for each element and circuit. Provide multistrand copper pigtail and interconnecting wires
with high temperature (454 degrees C850 degree F) insulation. Furnish heater pigtails with
strain relief constructed to prevent damage to the heater modules due to rough handling. Provide
pigtails of sufficient length to reach the terminal box. Splices are not permitted in pigtails
from modules, tapes, or blankets to the terminal box. Perform hopper heater module voltage
tests for each module, blanket, or tape for electrical integrity at 1,000 volts. Provide heating
modules with metal labels firmly attached to the module listing the wattage and voltage of the
module. Construct heating modules and mounting hardware of high temperature materials capable
of withstanding 454 degrees C 850 degrees F. Insulate heating modules with high temperature
woven glass cloth or mineral fiber. Mica or magnesium oxide insulated heaters are not acceptable.
b. Hopper Heater Installation: Heater modules shall provide maximum contact between the heaters
and the hopper wall.
2.5.3.2 Hopper Heater Controls
NOTE: Use these paragraphs for local control only.
NOTE: Use these paragraphs for master control only.
Control each hopper heater zone thermostatically with adjustable setpoint and provide complete including power,
control and alarm components. Provide 120 volt AC adjustable type thermostats for monitoring hopper temperature
and locate in NEMA ICS 6, Type 4 enclosures. For thermostatic control of the hopper heater system, provide a
Master Hopper Heater Control Panel for each precipitator, a Local Hopper Heater Control Panel for each hopper,
and a Local Hopper Heater Zone Terminal Box for each zone. Provide materials, tools, and labor required for
connections of circuits and wiring between local hopper heater zone terminal boxes, local hopper heater control
panels, and the master hopper heater control panels.
NOTE: Use these paragraphs for local control only.
a. Local Hopper Heater Zone Terminal Box: Provide hot-dipped galvanized NEMA ICS 6, Type 4
hopper heater terminal boxes with terminal blocks for connection of heater pigtails and thermostat
leads on each hopper for each hopper zone. Provide a sufficient number of terminals to connect
the heater pigtails and thermocouples for each hopper zone.
NOTE: Use these paragraphs for local control only.
b. Local Hopper Heater Control Panel: Provide each precipitator with a local hopper heater
control panel at each hopper. Locate at a regularly accessed area near each hopper. For each
zone, provide each local hopper heater control panel with: terminal blocks for power, control,
and alarm circuits, one control temperature thermostat, one low temperature alarm thermostat,
magnetic contactor and alarm relay with two normally open contacts, and auxiliary relays for
automatic operation of the heater system. Provide a 3-pole fused switched main disconnect device
and a fused control transformer having a 120-volt AC secondary for each local hopper heater
control panel. Provide thermostats with a set point range of 38 to 260 degrees C 100 to 500
degrees F. Measure hopper skin temperature using ungrounded, type J thermocouples. Provide
each local hopper heater control panel cover with the following devices:
(1) "START UP," "ON LINE," "OFF," "AUTO" selector switch.
(2) 120 V "ON" red light with integral transformers, one each zone.
(3) 120 V "LO TEMP" alarm white light with integral transformer, one each zone.
(4) Device and enclosure nameplates.
Wire the selector switch for the following system operation:
(1) "START UP": Upper and lower zones all elements on (includes throat heater).
(2) "ON LINE": Single element lower zone on (includes throat heater).
(3) "OFF": All elements off.
(4) "AUTO": Control functions transfer to Master Hopper Heater Control Panel.
NOTE: Use these paragraphs for master control only
c. Master Hopper Heater Control Panel: Provide panels containing relays, contactors, circuit
breakers, control transformers, and other devices required for complete control of each precipitator
hopper heater system. Locate Master Hopper Heater Control Panels with precipitator controls
in the control room. Factory install and wire the panel components in a NEMA ICS 6, Type 12
enclosure and include the following:
(1) A main circuit breaker.
(2) A circuit breaker and contactor alarm relay with two normally open contacts for each hopper
zone. The contactor shall have a 120-volt operating coil.
(3) "START UP," "ON LINE," "OFF," selector switch for each hopper.
(4) 120 V red "ON" light and 120 V white "LO TEMP alarm light with integral transformers for
each hopper zone.
(5) Auxiliary relays and equipment required for operation of the heating and alarm systems.
(6) Device and enclosure nameplates.
(7) Fused control transformer having a 120 volt AC secondary.
2.5.4 Fly Ash Level Alarms
Provide each hopper with a fly ash level alarm utilizing nuclear type detectors. The detectors shall be single
point gamma source and detection units. Provide the detectors complete with separately mounted electronic units
including local high level indicating light and relays for use with annunciation system herein specified. Provide
relays rated at 10 amperes, 120 volts AC, or 125 volts DC continuous duty. Provide dustproof switch housing
for hoppers and mount at one easily accessible location. Locate alarm indicators and detector and source electronics
at the hopper control panel. Provide detector that is explosion proof, waterjacketed, and able to withstand
vibration and temperatures up to 427 degrees C 800 degrees F. Provide the source with a lockable shutter mechanism
operated by an external handle to totally isolate the beam when in the closed position. Furnish electrical wiring
schematics. Electrical supply shall be 120 volts, single phase, 60 hertz. Provide two sensors for each hopper--one
at the alarm level and one at the empty level. Locate alarm level at the 50 percent hopper capacity level.
2.5.4.1 Temperature Range Requirement
Level reproducibility shall be within one inch. Outdoor components shall operate between minus 40 and 93 degrees
C 40 and 200 degrees F.
2.5.4.2 Cesium Source Safety Systems
Provide Cesium 137 source for each hopper. Design source head with a spring return off system in the event of
remote cable actuator failure. Interlock source with hopper access doors to prevent entry into hopper unless
source has been secured. Hopper access door key shall only open one pair of hopper doors.
2.5.4.3 Hopper Level Indicator
Hopper level signals, based on hopper level status indicator system, shall report to a microprocessor through
a coaxial cable system. Provide each hopper with two indicators, one for full and one for empty. A flashing
light shall indicate a wall buildup. Loss of power for any period of time shall not require a recalibration.
Provide NEMA ICS 6, Type 4 enclosure for microprocessor.
2.5.4.4 Alarm System
Incorporate each group of detector units for a single electrostatic precipitator into the unit alarm system for
its respective precipitator so that a high level in any hopper shall indicate as part of the unit alarm system.
2.6 ACCESS
2.6.1 Walkways
Provide walkways for inspection and maintenance of discharge electrode hanger points. Access doors and external
walkways shall make routine inspection tours readily performable. Connect walkways, including roof, by stairways.
Interconnect walkways at each level by walkways at the same level. Provide caged ladders as a means of secondary
egress connecting all levels.
2.6.2 Doors
Provide every access door with a corresponding exterior walkway connected to the general system of platforms
and walkways. Provide insulated, hinged, quick opening access, inspection, and clean out doors with gastight
seals. Access doors, including hopper doors, and mechanical and electrical components shall be easily accessible
from the walkway or provide with a permanent steel ladder or stairway to facilitate maintenance. Provide internal
and external handholds at all access doors to facilitate entry.
2.6.3 Platforms, Walkways, and Ladders
Shop fabricate walkways, stairways, and ladders. Provide access to openings in both the precipitator and hoppers.
Provide walkways in the casing interior as specified in paragraph entitled "Housing." Provide walkways, platforms,
stairways, ladders, handrails, and kickplates on the penthouse roof and housing roof, as applicable, and as specified
in paragraph entitled "Penthouse." Design platforms, ladders, and walkways support steel for live load specified
herein. Design platforms to support a 488 kg per square meter 100 pound per square foot live load. Construct
external walkways and platforms of steel conforming to ASTM A 242/A 242M raised pattern floor plate.
2.6.4 Maintenance
NOTE: Provide 227 kg 500 pound crane unless T/R sets are to be replaced with
the crane. If used for T/R replacement, size for T/R weight.
Provide jib crane as required to remove roof-mounted equipment. Load limits shall be [_____] kg pounds and the
jib crane shall be properly signed for safety showing maximum load permitted.
2.6.5 Hot Dip Galvanizing
Hot dip galvanize platforms, walkways, stairways, ladders, handrails, and kickplates after fabrication in accordance
with ASTM A 123/A 123M. Minimum galvanized coating per surface shall not be less than [_____] kg per square
meter ounces/square foot.
2.6.6 Gas Distribution Devices
Provide the precipitator with inlet and outlet screens or baffles required to obtain proper gas distribution
across the face of the precipitator as determined by model test study. Gas distribution devices shall contain
removable 915 by 610 mm 3 by 2 feet panels on each screen or baffle for access between screens. Provide the
precipitator with internal gas baffles as required to prevent gases from bypassing the treatment zone. Gas distribution
velocities across the inlet to the precipitator shall have a root-mean-square deviation of no more than 15 percent
and no flow shall exceed 125 percent of average flow velocity.
2.6.7 Interlocks
Provide a key type safety interlock system with sequential key arrangement on the precipitator housing and penthouse
access doors, inlet and outlet nozzle access doors, rectifier enclosure access doors, transformer-rectifier grounding
switch, hopper level indicator sources, hopper access doors, and control unit circuit breakers. No high voltage
equipment shall be accessible without properly locking out the power supply and grounding the high voltage equipment.
Keys shall not be able to be removed from the locks when access doors are open.
2.7 FABRICATION
Perform shop fabrication and assembly of steel structures in conformance with AISC Specifications, Codes and
Standards. Field welding shall be shielded metal arc or submerged arc. Shop welding shall be shielded-metal
arc, submerged arc, flux-core arc, or gas metal arc. Perform welding in conformance with the requirements of
the AWS D1.1/D1.1M and AISC Specifications. Shop connections shall be welded, riveted, or bolted with high-strength
bolts at the Contractor's option and as allowed by the seismic code. Unless restricted by consideration of clearance
or seismic design criteria, show field connections as bolted friction type using ASTM A 325M ASTM A 325 or ASTM A 490M
ASTM A 490 bolts and design to conform to AISC specification for "Structural Joints Using ASTM A 325M ASTM A 325
or ASTM A 490M ASTM A 490 Bolts." Form and weld handrails and do not exceed 6 feet from center-to-center of
posts. Grind welds smooth and even with the surface of the pipe, remove weld splatter. Carefully form transitions
at corners where change of direction of elevation occurs as required to provide continuous handrail. Clear columns
or other vertical or horizontal projections by at least 80 mm 3 inches. Furnish plates and additional items
as required for fastening to supporting members. Extend kickplates 100 mm 4 inches above top of grating and
install at the edge of uncovered openings and at the edge of walkways and platforms. Construct kickplates to
allow water run-off. Shop fabricate as complete as possible and within standard industry practice. Leave large
pieces unassembled only to the extent necessary for shipment.
2.8 PAINTING
Steel surfaces shall be dry and clean before painting. Remove grease, oils, and contaminants as outlined in
SSPC SP 1. Remove weld spatter and grind burrs smooth on cut edges and rough welds. Blast-clean surfaces after
fabrication, in accordance with SSPC SP 6 and profile depth of 0.038 to 0.051 mm 1.5 to 2.5 mils. Before any
rust bloom forms, apply one coat, dry film thickness of 0.076 mm 3 mils, of any of the organic zinc-rich primers
meeting the requirements of SSPC PS 12.01, with a minimum of 82 percent zinc in the dry film. Apply primer in
accordance with manufacturer's recommendations. Apply primer to steel surfaces except the areas within 50 mm
two inches adjacent to field welds and surfaces specified to be hot-dip galvanized.
PART 3 EXECUTION
3.1 FACTORY INSPECTION
Any material or equipment used in the manufacture of the precipitator and found to be defective during inspection
at the manufacturer's plant shall be either corrected or replaced as approved by the Contracting Officer before
shipment. Acceptance at the factory shall not constitute final acceptance.
3.2 INSTALLATION
NOTE: Revise this paragraph as necessary when it is desired to have the precipitator
manufacturer install the equipment furnished.
The contractor shall install the equipment specified herein on foundations or structural-steel framework shown
on the drawings or as specified elsewhere herein. Installation shall be in accordance with the manufacturer's
recommendations.
3.3 MANUFACTURER'S FIELD REPRESENTATIVE
NOTE: The period of instruction should be reduced only if the operating personnel
have significant experience on identical equipment.
The contractor shall provide the services of a field representative(s) specifically trained by the manufacturer
to assist installers of their equipment. The field representative(s) shall be at the erection site during installation
including unloading, hauling, storing, cleaning, erecting, and testing. The field representative(s) shall supervise
the adjustment of all controls, control devices, and components supplied with the precipitator as necessary to
place the precipitator in successful operation. The field representative(s) shall instruct the plant operators
in the operation, care, and maintenance of the equipment. Provide a minimum of 10 working days advance notice
to the Contracting Officer prior to scheduling these instructions. Provide a total of [20] [_____] days instruction
including [6] [_____] round trips to the jobsite. Provide training by field representative in precipitator theory
and design, start-up, shut-down, operation, performance monitoring, performance evaluation, problem diagnosis,
maintenance, inspection methods, safety, operations and maintenance plans.
3.4 FIELD TESTS AND INSPECTIONS
3.4.1 Delivery Inspection
Materials and equipment shall be inspected in accordance with the Contract Clauses. Inspections may be made
to assure that equipment and installation comply with local and government requirements for equipment and safety
as well as applicable specifications.
3.4.2 Post Installation Inspection
A factory service engineer employed by the precipitator manufacturer shall inspect the precipitator after installation
is completed and prior to startup to verify that the unit is installed in conformance with the manufacturer's
recommendations. Perform an air load test with precipitator readings recorded.
3.4.3 Performance Tests
Perform field performance tests by an independent testing organization acceptable to the Contracting Officer.
Provide written notice to the Contracting Officer, at least 20 calendar days before scheduled test date, stating
that equipment is being scheduled for test. Perform a trial run of 30 days minimum before actual test (operate
boiler at least 60 to 90 percent load) to ensure that associated systems required for the test are ready. Perform
boiler tune-up to optimum efficiency prior to performance test. The Contractor and the manufacturer's factory
service engineer shall witness the test. Perform tests in accordance with applicable state or local methods.
If no such methods or adaptations are required, then perform the tests in accordance with EPA 40 CFR 60, Appendix
A, Methods 1-5, 9 and 17. Perform tests at the maximum continuous rating for the inlet gas conditions specified
in paragraph entitled "Inlet Gas Conditions" and, if applicable, at other operating conditions that are required
for approval by the appropriate regulatory agency. Test the precipitator for efficiency by simultaneous testing
of precipitator inlet and outlet emissions. Conduct the efficiency tests after the precipitator has been in
operation for at least 45 days.
3.5 IDENTIFICATION
Fasten an aluminum, brass, or corrosion-resistant steel nameplate to the equipment in a readily visible location
by means of stainless steel Series 300 rivets or sheet metal screws. The nameplate shall contain data such as
the manufacturer's name, and model or series number. Indent or emboss the information in the metal. Offset
the nameplate a sufficient amount to avoid being covered by insulation.
3.6 INSULATION INSTALLATION
3.6.1 General Insulation Requirements
Apply insulation with interruptions to permit access doors, inspection doors, flanges, and other special features
to be opened or removed for inspection or maintenance without disturbing the insulation. Provide boxouts around
code stamping symbols and nameplates. Install double thickness insulation with the joints of the two layers
staggered. Fill cracks, voids, and depressions in layers of insulation with suitable insulating cements before
application of another layer of insulation or jacket application. Provide expansion joints in the insulation
as required to allow for thermal expansion movements which might cause cracks or tears in the insulation. Install
insulation between stiffeners and over stiffeners so that stiffeners are completely insulated. Install additional
insulation or casing spacers between stiffeners so that a level surface is achieved. The intent of this insulating
procedure is to prevent a direct metal path between the precipitator inside and ambient air. Securely wire and
lace in place insulation using number 14 dead soft Type 302 stainless steel wire, conforming to ASTM A 580/A 580M
.
3.6.2 Block and Mineral Fiberboard Insulation Installation
Secure block and mineral fiberboard insulation in place with insulation lugs spaces on not greater than 300 by
460 mm 12 by 18 inchcenters. Provide stud type lugs welded in place. Reinforce blocks on the exterior face
with expanded metal if necessary to prevent sagging or cutting of the insulation by the lacing wire. Securely
wire block and mineral fiberboard insulation of the specified thickness in place over the entire surface by means
of wire threaded through the lugs both ways, pulled tight with the ends of the wire loops twisted together with
pliers, bent over, and carefully pressed into the surface of the insulation.
3.6.3 Mineral Fiber Blanket Insulation Installation
Secure mineral fiber blanket insulation in place with speed washers and impaling pins spaced on centers not exceeding
300 mm 12 inches. Provide mineral fiber blanket insulation with expanded metal reinforcement on the outer surface
and wire mesh or expanded metal on the inner surface. Tightly butt sections of the blankets together and securely
tie for maximum sealing at joints. Secure the blanket at joints to prevent peeling or bulging away from blanket
edges. Do not reduce the design thickness of insulation when applying speed washers.
3.6.4 Housing Hot Roof
Install calcium silicate insulation conforming to ASTM C 533 over 12 gage steel pins stud welded on 610 mm two
foot centers to the surface to be insulated. Hold the insulation in place by 65 mm 2 1/2 inch square speed washers
and closely fit around penetrations. Construct top surfaces of steel conforming to ASTM A 242/A 242M raised
pattern plate not less than 6 mm 1/4 inch thick and suitably support to bear 488 kg per square meter 100 pounds
per square foot live load. Seal joints by continuous fillet or complete penetration groove welds as applicable.
Weld appurtenances similarly to the plate. Provide top penetrations with a 50 mm 2 inch minimum extension above
the plate and similarly weld to the plate.
3.7 PROTECTION FROM INSULATION MATERIALS
Protect equipment and structures from damage from insulation materials. After completion of the work, clean,
repair, and restore equipment and structures to their original state. Repair any casing which becomes corroded,
discolored, or otherwise damaged by replacing of casing or other means acceptable to the Contracting Officer.
3.8 CASING INSTALLATION
3.8.1 Structural Steel Grid System
Install casing over exterior insulated surfaces on an aluminized structural steel grid system of subgirts designed,
furnished, and installed by the contractor. Provide subgirts of sufficient size, gage, and depth to provide
adequate support and a smooth exterior surface and weld to the equipment and structural support surfaces. Provide
subgirts of sufficient depth to provide for application of the full thickness of insulation over the stiffeners,
access doors, flanges, ribs, and other surfaces having uneven contours to provide a smooth finished surface.
Provide subgirts on vertical and bottom surfaces at a maximum spacing of 1.22 meters 4 feet on centers. Provide
subgirts on roof surfaces at a maximum spacing of 610 mm two feet on centers. Provide a roof surface system
that will transmit an external 114 kg 250 pound walking load from the casing to the structural steel grid system
without compression of the insulation material.
3.8.2 Access Openings
Closely fit insulation to fittings around access doors and other penetrations through the insulation. Neatly
frame and flash to make weathertight and to create a pleasing appearance. Provide insulated hinged or lift-off
doors designed for convenient opening or removal at nameplates, code stampings, nonprojecting connections, and
access openings. Pitch access openings for water runoff and have flashing at door head as shown in SMACNA 1793
.
3.8.3 Weatherproofing
Install casing with proper overlap to make the installation weathertight. Fabricate and fit the casing to ensure
a neat appearance. Provide closures, flashings, and seals required. Provide the open ends of fluted sections
with tightfitting closure pieces. Suitably form and install flashing so that water cannot enter and wet the
insulation. Design and install flashing to readily drain any water that might enter. Weatherproof joints or
openings in casing which cannot be effectively sealed from entry of moisture by application of an aluminum-pigmented
sealer manufactured for this type of service.
3.8.4 Convection Stops
Provide steel channel or Z-girt convection stops on all vertical surfaces over 3.66 meters 12 feet tall. The
maximum interval between convection stops shall be 3.66 meters 12 feet.
3.8.5 Casing Attachment
NOTE: If a separate insulation section is part of this specification, add a
note to that section to indicate that insulation of the precipitator is covered
by this section.
Attach aluminum casing to the steel structural members by means of Number 14 stainless steel Series 300 self-tapping
screws on 305 mm 12 inchcenters. Fasten vertical laps and flashing by means of 20 mm 3/4 inch Number 14 stainless
steel Series 300 sheet metal screws on 305 mm 12 inch centers. Provide exposed screws with aluminum of stainless
steel backed neoprene washers preassembled to screws. Do not compress insulation below nominal thickness when
installing screws.
3.9 HEATER INSTALLATION
Thoroughly clean hopper surfaces prior to heater module, tape, or blanket installation. Install the heater module
so the module surface contacts the hopper wall to the maximum extent possible. Provide heaters with necessary
mounting hardware, channels, and brackets. Install throat heaters so the heater conforms to the surface of the
throat and contacts the throat to the maximum extent possible. Do not overlap throat heaters. Hold throat heaters
in place with high temperature (454 degrees C850 degrees F) glass tape or other means acceptable to the Contracting
Officer. Completely cover the throat heater with the glass tape prior to lagging.
3.10 WIRE NUMBERS
Provide wire numbers on both ends of each wire appearing on the elementary diagram. Use space terminals for
terminations. Markers shall be white plastic sleeves with black letters.
3.11 GALVANIC CORROSION PREVENTION
To prevent galvanic corrosion, prevent permanent contact of aluminum casing with copper, copper alloy, tin, lead,
nickel, or nickel alloy including Monel metal. Where it is necessary to attach the casing to carbon steel or
low alloy steel, paint the steel with zinc chromate primer. Then paint with aluminum paint suitable for surface
temperatures encountered. Do not use lead base paint.
3.12 PAINTING
Provide field painting of those surfaces of the following equipment not in contact with the flue gas stream:
precipitators, cyclones, fans, and breeching. Field paint as specified in Section 09 90 00 PAINTS AND COATINGS.
Paint other equipment provided in this section; either field paint with paint systems conforming to Section
09 90 00 PAINTS AND COATINGS or paint with factory or shop painting systems conforming to the requirements specified
in Section 23 03 00.00 20 BASIC MECHANICAL MATERIALS AND METHODS.
3.13 SCHEDULE
Some metric measurements in this section are based on mathematical conversion of inch-pound measurements, and
not on metric measurements commonly agreed on by the manufacturers or other parties. The inch-pound and metric
measurements shown are as follows:
Products Inch-Pound Metric
a. [_____ _____ _____]