Section 8 — Heat Transfer Equipment

Packaged Watertube Boilers

IPE Engineering Practice IPE-EP-8-3-1

Document number: IPE-EP-8-3-1 · Section: 8 — Heat Transfer Equipment

GUARANTEE 23

• Process Guarantee 23
• Performance Guarantee 23
• Mechanical Guarantee 24

12.0 CERTIFICATION 24

13.0 TABLES 25

Table 1 Performance Criteria 25Table 1 Performance Criteria 25

Table 2 Maximum Heat Release Based On Hhv 27Table 2 Maximum Heat Release Based On Hhv 27

Table 3 Sootblower Selection Criteria 27Table 3 Sootblower Selection Criteria 27

Table 4 Steam Purity. 28Table 4 Steam Purity. 28

SCOPE

• This Practice covers the design, fabrication, and performance requirements of packaged fired watertube boilers having steam outlet conditions not exceeding 900 psig and 800°F.
• The Manufacturer must supply a base bid quotation that meets this Practice. Alternate bid(s) may be submitted, provided the performance specifications are met. All deviations from this Practice must be noted and approved by the procedures given in EP 1–1–3.
• This Practice should be used in conjunction with the Packaged Watertube Boiler Data Sheet, EP 8-3-1DS (to be completed by the Manufacturer). In cases of conflict between Data Sheets and the Practice, the Data Sheets take precedence.
• An asterisk (*) indicates that a decision by the Owner or the Owner’s Engineer is required or that additional information is furnished by the Purchaser.
• A revision bar indicates all changes made to this Revision.

REFERENCES

• All material and equipment shall be built to conform to Federal, State, and Local government requirements including, but not limited to the latest editions of the documents listed below.
• The latest edition of the following Standards and Publications are referred to herein.

STANDARDS AND PUBLICATIONS

STANDARDS AND PUBLICATIONS (Cont.)

DEFINITIONS

• Contractor - Company or business that agrees to furnish materials or perform specified services at a specified price and/or rate to the Owner.
• Inspector - A Inflection Point Engineering, LLC appointed engineer or inspector.
• Manufacturer - The recipient of a direct or indirect purchase order for materials and/or equipment. In this context, a direct order is one issued to a Manufacturer by a Contractor or the Owner. An indirect order is one issued to a Manufacturer by a vendor (recipient of a direct order) for materials, fabricated components, or subassemblies.
• Owner - Inflection Point Engineering, LLC
• Owner’s Engineer - A Inflection Point Engineering, LLC appointed engineer.
• Purchase Order - The contractual document given to the Manufacturer to authorize a purchase.

• Purchaser - The party placing a direct purchase order. The Purchaser is the Owner’s designated representative.

MANUFACTURER’S RESPONSIBILITY

• The Manufacturer shall furnish the items listed below. Any items not normally shipped completely assembled and ready for service connections, shall be indicated. Refractory should be suitably cured and braced or otherwise protected to prevent damage during transit.
• Steam generator complete with the following:
• Structural steel base and frame
• Casing
• Refractory and insulation
• Valves, instrument connections, and piping
• Other accessories as specified herein
• Ladders, platforms, and walkways in compliance with appropriate Safety Codes and EP 4–5–3.
• Fuel burning, equipment, complete with the following:
• Burners, burner piping, and pilots including pre–assembled fuel and pilot piping train in accordance with NFPA 85B and NFPA 85D
• Flame failure, with mounting brackets and peepholes and local burner control panel
• Draft fan(s) with driver, drive and guard
• Windbox and combustion air control damper
• All necessary duct work between fan and windbox
• (*) Sootblowers, when specified on Data Sheets, complete with piping and mounted in place
• Self supporting stack and breeching and stack damper if required.
• Provision for chemical cleaning: Flanged connections NPS 4 inch at all required locations with a sketch showing these locations.
• Any special tools required for installation, operation, or maintenance.
• Fuel oil storage, pumping and heating equipment, if required (Manufacturer to determine required pressure, temperature and flow, and inform the Owner).
• Instruments and control valves.
• Materials and labor as follows:
• All necessary foundations
• All piping, including its installation, from generator steam outlet, blow–off and feed water valves, and all connections to the Owner’s services including gas, oil, air, and electricity
• Insulation of piping described above
• All electrical wiring, instrument piping, and pneumatic tubing between master control panel and locally mounted devices and panels
• Motor starters and wiring from motor to starter
• All necessary platforms, walkways, stairways and related structural steel
• All labor for unloading and transporting the Manufacturer’s equipment from the point of delivery to the jobsite, for placing same on foundation, and for completing installation of the equipment

• A list of installations of similar design and capacity should be included in the proposal stating location and end users.

SERVICE CONDITIONS

• The boiler will be installed in an exposed, outdoor site, at the plant location noted on the Data Sheet. It will not have any weather protection supplied by others. When the winter temperature may drop below 27°F for extended periods, it may be necessary to make the entire installation suitable for service in freezing climate. All external surfaces exposed to weather conditions shall be self–draining and shall be protected against corrosion.
• The boiler shall perform satisfactorily when operated as either a base loaded unit, or as a peaking unit, responding to changes in the steam header pressure.
• The design of the boiler and its accessories shall protect it from damage due to abnormal operating conditions, such as turbine trip–out, full load rejection, and other rapid load fluctuations.

DESIGN

• Functional Design
• (*) The Manufacturer shall guarantee the performance and efficiency of the boiler at the design conditions specified on the Data Sheet.
• Carryover of solids shall not exceed a maximum of 1 ppm during load swings of up to 20% of capacity per minute.
• (*) The boiler shall be capable of operating at not less than 80% of fuel–to–steam efficiency at all rates within the operating range for all fuels specified on the Data Sheet.
• The boiler shall be properly designed to permit free liberation of steam during normal operation and during swings in steam demand of up to 20% of the maximum continuous rating (MCR) per minute when operated between 20% MCR and 90% MCR.
• (*) The burners shall be operable at the maximum turndown rates specified on the Data Sheet, with stable flames and without any evidence of poor combustion.
• Heat distribution throughout the furnace shall be as uniform as possible under all conditions, and the flame shall not impinge directly on the boiler heating surface under any circumstances.
• The boiler and auxiliaries, including control instrumentation, shall be designed for continuous operation during electrical power outage for a minimum period of 30 minutes.
• The Manufacturer shall correct all deficiencies in design, workmanship and materials in a minimal amount of time at no cost to the Owner.
• General Mechanical Design
• The design and construction of the boiler including all auxiliary facilities shall be of commercially proven design.

• For shop assembled units, the boiler, burner(s), all necessary appurtenances and auxiliary equipment shall be mounted on an integral steel base to provide a complete self–contained unit within the constraints of shipping limits. All vibration sensitive equipment must be shock mounted. The fans and drivers, air preheater and/or economizer may be shipped separately for the shop assembled boilers.
• The furnace and gas passes shall be designed to prevent dead ended or poorly ventilated pockets in which combustibles can accumulate and cause an explosion upon ignition.
• A minimum corrosion allowance should be provided as follows:
• Boiler Drums and Headers, 0.06 inch.
• Boiler tubes including Superheater tubes, 0.04 inch.
• Economizer tubes, 0.04 inch.
• All outside walls shall be of the all welded or membrane wall construction. Welded or membrane walls shall be fabricated by machine welding fins to the tubes or by welding extruded fin tubes into gas tight panels. Spacing between tubes shall not exceed 1 inch. Fins shall be at least 1/4 inch thick.
• To the extent practical, all water wall tubes shall be directly connected to both the lower drum and the steam drum. When intermediate headers are required, the headers shall be protected from radiant heat and flue gases.
• All headers shall be fabricated from seamless steel pipes and shall be provided with inlet and outlet nozzles, inspection openings, drains, vents, blowdown, and acid wash connection.
• (*) The Data Sheets specify the steam pressure at which the boiler is expected to operate. The Manufacturer shall furnish his nearest standard pressure design which is not less than 10% above the expected operating pressure.
• The Manufacturer shall guarantee all equipment supplied against defective material, poor workmanship, improper design and failure from normal usage for a period of 1 year after being placed in normal operation.
• Welding and design shall conform to the requirements of the ASME Boiler Code and EP 7–1–5.
• Furnace Design
• The furnace dimensions and design shall be such that complete combustion of the fuel takes place within the furnace with no flame impingement on the side walls, roof, target wall or any other tube.
• Based on design fuel high heating valve, HHV, the maximum heat release at maximum continuous rating in the furnace shall not exceed the limits shown in Table 2.
• Drums
• The drums shall be complete with all necessary manways, nozzles, connections, and internals as required for safe, efficient and reliable operation, easy cleaning and maintenance.
• No drum or header shall be exposed to the direct radiant heat of the furnace.

• The upper steam and water drums shall not be less than 54 inches (outside) diameter. Lower drums shall not be less than 24 inches (outside) diameter. Access manways shall not be less than 12” x 16” and shall be provided at each end of the steam drum, and at least one end of all other drums. Drums should be of fusion welded construction (stress relieved with seams 100% X–rayed) per the ASME Boiler and Pressure Vessel Code, Section I and the applicable sections of EP 7–1–1. The steam drum should be provided with compartment baffle and centrifugal cyclone type separators and a low velocity scrubber to insure the highest quality steam. The Manufacturer is to specify the type of baffle offered.
• The maximum hardness of all finished carbon steel vessel welds shall be 200 BHN. The Manufacturer shall provide supporting proof that all welds meet this requirement.
• Connections
• Connections on drums shall not be less than NPS 1 inch. Where less than NPS 1 inch connection is required, a reducing fitting shall be used. Screwed connections are not allowed.
• Drums shall be provided with at least the following connections, and corresponding sizes suitable for the service specified.
• Main steam outlet
• Pressure relief per EP 5–3–14
• Intermittent Blow–Down and Drain
• Continuous Blow–Down
• Feed water inlet
• Chemical feed
• Water column
• Drum level transmitter plus separate high and low alarm and shutdown
• Vent
• Steam pressure gauge
• Manholes or handholes
• Steam sampling connections per ANSI/ASTM D1066
• Tubes
• Steam generating tubes shall be seamless or electric resistance welded carbon steel. When offering electric resistance welded tubes, Manufacturer details shall be included in the proposal. Tubes shall be of sufficient size to provide the natural circulation at all loads. The minimum outside diameter for all tubes shall be 2 inches. For studded tubes, the minimum original wall thickness shall be 0.22 inch for mechanical strength during studding.
• The tube bends shall be of large radius and the tubes shall not contain any restrictions which would limit use of standard commercial tube cleaners. The design shall provide for adequate chemical cleaning and flushing of all tubes. Bends shall be the same material as the highest alloy material to which they attach. Tube and bend thicknesses shall be per ASME Section I with corrosion allowance equal to 0.25t. The minimum tube/bend thickness shall be 0.156 inch.
• All boiler tubes shall be completely drainable with no bends below the horizontal.
• The header and tube arrangement shall be such that all tube interiors are accessible to inspection techniques such as eddy current NDE.
• All furnace water wall tubes shall enter the steam drum below the water level.

• Where welded wall furnace construction is used, the solid bar between tubes shall not exceed 7/8 inch in width.
• Handholes in headers shall not be smaller than 2–3/4 inches x 3–1/2 inches.
• Piping and Valves
• (*) Valves furnished by the Manufacturer, after approval by the Purchaser, shall generally include at least one (1) valve for each pressure part nozzle and specifically include the following:
• Main steam outlet stop valve and non–return valve
• Steel safety valves in number, size, and type as required by the ASME Boiler Code, Section I.
• Two (2) blow–off valves installed in tandem at each blow–off point
• All necessary drain and vent valves including economizer (or preheater), superheater, and drums
• Feed water stop and check valves
• Continuous blow–down, shut–off and throttling valve
• Chemical feed shut–off valve
• Shut–off valves and blow–down valves for water column and gauge glass
• Shut–off valve for pressure gauge
• Shut–off valve for sootblower
• All valves which are operated frequently shall be located hand–high above the operating floor.
• The Manufacturer shall furnish all piping to connect equipment and valves, furnished by the Manufacturer, to the boiler. This piping shall be shop installed and tested, unless shipping clearances prohibit. The piping and fittings shall be in accordance with ASME Code, Section I and EP 5–1–1.
• Internals
• The steam drum internals are to include the steam collecting system and all necessary internal piping such as chemical feed, continuous blowdown, and feedwater distribution.
• Continuous blowdown gathering pipe shall be provided in the steam drum designed for even distribution at the percent blowdown specified.
• Internal piping shall be provided in the lower drum(s) for the collection and removal of sediment.
• Downcomers and drum internals shall be designed to insure positive circulation under all load conditions.
• For boilers operating over 500 psi, steam drum internals shall include centrifugal–type primary separators. Separators shall be sealed below the water level. Complete details of the separators shall be provided by the Manufacturer.
• (*) Proposals to use other types of primary separators shall be submitted to the Purchaser for approval by the Owner’s Engineer. To be considered for approval, the Manufacturer must substantiate with test data from a commercial unit that the solids content of steam entering the super–heater will not exceed 0.5 ppm when operating with normal water level and with the specified boiler water concentration.

• Intermittent Blow–down nozzles shall be located on the bottom of the lower drum as well as the lowest points of all water distribution headers. The size shall not be less than NPS 1–1/2 inch.
• Economizer
• (*) When specified on the Data Sheet, the boiler shall be equipped with a shop assembled, continuous, drainable, finned tube economizer of the non–steaming type, arranged for counterflow. It shall contain sufficient surface to reduce the exit gas temperature to 350°F when burning oil (300°F when burning gas) at the design rate. However, the economizer design shall consider the flue gas dew point with respect to tube skin temperatures to prevent excessive corrosion and fouling.
• (*) Economizer tubes should be a minimum of 2 inch O.D., seamless carbon steel, and arranged in line with a clear side spacing of 1 inch to minimize the possibility of plugging the gas lanes. Tubes shall be arranged in staggered rows, unless approved by the Owner’s Engineer.
• The economizer shall be equipped with wall boxes and tube bearings for the installation of sootblowers.
• The finned tube economizer surface shall have a maximum of 3 fins/inch, 3/4 inches high. The minimum fin thickness shall be 0.105 inch.
• The economizer should be of such design to allow for inspection access.
• Superheater
• (*) Each boiler shall be equipped with a completely drainable, inverted loop, convection or radiant convection type superheater preferably located behind screen tubes. Elimination of the superheater screen tubes and non–drainable superheaters require approval from the Owner’s Engineer.
• The inlet and outlet headers shall not be less than 9–1/4 inch O.D. with a minimum wall thickness in accordance with the ASME Code, Section I. The header material shall be in accordance with the ASME Code and suitable for the temperature conditions. Headers shall be complete with hand hole caps. Each of the lower headers shall contain at least one 1 inch drain connection complete with a drain valve. The outlet header shall have a flanged steam outlet nozzle and a separate flanged safety valve nozzle and vents. The safety valve shall be furnished by the Manufacturer. Superheater vent connections shall be equipped with a silencer.
• (*) Connecting tubes and superheater tubes shall be not less than 2 inch O.D. and shall have thickness and material in accordance with the ASME Code and suitable for the temperature conditions. As a minimum, the superheater preferably is to be protected from furnace radiation by at least two rows of evaporation tubes and the material shall be based on the highest metal temperature at the worst conditions, with maximum flow unbalance and a fouling factor. Design calculations shall be submitted to the Owner’s Engineer for approval.
• Superheater headers and tubes shall be designed to assure balanced flow between passes within plus or minus 2 percent.
• The Manufacturer shall furnish a curve showing the steam outlet temperature versus steam rate over the entire operating range.
• Inlet and outlet headers and their supports shall be located outside the gas passes. Superheater elements and headers shall be located and supported so as to prevent vibration, sagging and misalignment.

• (*) The outlet header shall have appropriately located thermowell, test gauge and pressure gauge connections. Thermocouples shall be installed on a minimum of 25 percent of the passes and on both end passes for monitoring the superheater tube metal temperatures. Details of thermocouples and their installation shall be provided for approval by the Owner’s Engineer.
• Desuperheaters

When required to maintain the steam temperature at the superheater outlet within required limits at any expected load or firing condition, a desuperheater of the shell and tube type or a direct contact spray attemporator may be used. If a direct contact spray attemporator is used, condensate shall be used as the quench medium and shall be supplied by a separate centrifugal pump provided by others.

• Casing, Observation Ports and Access Openings
• Waterwall tubes shall be either fin–welded or skin cased to form a pressure–tight envelope to protect insulation and the outer casing from flue gas contact. Skin cased designs shall meet the following requirements.
• The tubes shall be tied together to prevent their bowing out of plane.
• The skin casing shall be placed directly behind and tied to the tubes.
• The skin casing shall not see burners or radiant heat.
• Skin cased units shall have a minimum inner casing thickness of 3/16 inch and outer casing thickness of .049 inch (USS gauge 18). The internal surface of the casing shall be protected against corrosion.
• The tangent tube wall casing shall be located directly behind the furnace boiler tubes. The minimum casing plate thickness shall be 0.14 inch (USS gauge 10). The space between the back face of the boiler and the furnace tubes and the inner casing shall be filled with dense weight castable refractory (80 #/ft 3 minimum), or equal.
• All materials, design and construction shall be suitable for temperatures and differential expansions involved and shall absorb vibrations without leaking, cracking, breaking or displacing the refractory or insulation.
• The entire boiler enclosure shall be weathertight and capable of withstanding the highest of the following without buckling or bowing.
• One and one–half times the maximum internal pressure that can be predicted at peak load
• Ten inches of water gauge
• Maximum forced draft pressure
• A smoke test will be required.
• Drains shall be furnished at the low point of the boiler furnace and generating bank areas to permit removal of flue gas deposits by water washing. Openings shall be a minimum of 3 inches in diameter. Drain openings shall be properly sealed against flue gas bypassing and casing overheating.
• Observation (view) ports shall be provided to meet the following requirements:
• Be located to permit total visibility of all burners, flame envelope, furnace surfaces and superheater cavity.
• Ports shall be insulated and easily accessible from platforms or ladders.

• The minimum open area through the glass shall be 2 inches by 4 inches or 3 inches in diameter.
• On pressurized boilers, observation ports shall be furnished with aspirating air of sufficient pressure to prevent flue gases from blowing out when the door is open. Each door shall be fitted with an interlock which prevents the door from being opened unless the aspirating air is turned on. Seal air shall be circulated to minimize flue gas leakage and prevent fogging of the view glass when the door is closed.
• Two bolted access doors, as far apart as practical, shall be provided into each boiler compartment. Each shall be gas tight, refractory lined and shall have minimum dimensions of 18 inch by 24 inch (24 inch by 24 inch preferred). The superheater shall be accessible.
• Refractory and Insulation
• The Manufacturer shall furnish in place all materials necessary to completely refractory line and insulate the boiler per EP 11–1–1, EP 11–1–2 and EP 11–3–3.
• The thickness of insulation may be Manufacturer’s standard, but shall be of sufficient thickness so that the outer casing temperature will not exceed 130°F in an ambient temperature of 80°F, with surface wind velocity of 50 FPM, while the boiler is operated at rated capacity.
• Combustion settings, walls, and floors shall be constructed to permit free expansion of the boiler without placing undue stress on any part of the boiler setting.
• All hot surfaces of equipment and structures fumished shall be insulated per EP 11–3–1 and EP 11–3–3 including the following:
• Boiler drum, shells, and heads
• Flue gas breeching and duct work
• Exposed portions of boiler and furnace wall tubes
• Ecomomizer
• Manufacturer supplied, exposed piping in hot water or steam service. This shall include exposed economizer, superheater, and saturated steam headers.
• Windbox
• The windbox shall be mounted on the front of the boiler and shall contain the necessary damper guide vanes, and rounded inside corners to ensure equal distribution of combustion air to the air registers of each burner.
• The windbox shall be made out of a minimum of 1/4 inch steel plate and shall be designed to withstand the maximum air pressure without deflection or vibration, and shall be provided with a bolted access door.
• Baffles
• Baffles, when used, shall be arranged so as to diffuse the gas properly over the heating surface to obtain maximum heat adsorption, and shall be held securely in place without being affected by, or interfering with, free expansion or contraction of the boiler.
• Baffles shall in no way pocket gas which may cause an explosion.
• Metal and/or refractory baffles, including baffle supports, shall be capable of withstanding the temperature existing under 110 percent of the maximum load conditions.

• Structural

• The Manufacturer shall furnish a welded steel structural base which shall form an integral part of the unit. The structural steel shall be in accordance with EP 4–5–1.
• The tensile stress on foundation anchor bolts shall be limited to 15,000 psi.
• Boilers that have continuous tangent tubes or fin welded furnace floor tubes shall be elevated a minimum of 3 feet to permit access beneath the furnace floor.
• Auxiliary structures for operation and maintenance including, but not limited to, platforms, ladders and stairways, shall be in accordance with EP 4–5–3.
• Provision shall be made for thermal expansion of all required components including, but not limited to, casing, ducting, boiler selling, structures and tubes.
• Lifting lugs shall be furnished, securely welded to the unit.
• Flues, Ducts and Stack
• The Manufacturer shall furnish flues from the boiler outlet to the economizer and from the economizer to the ground mounted stack. The stack shall be designed and fabricated per EP 4–7–1.
• Stack diameter shall be sized for the following exit velocities:
• At design conditions, exit velocity shall be a minimum of 25 fps
• For extended turn down operations, the exit velocity shall be a minimum of 15 fps
• (*) The minimum stack height shall be specified by the Owner.
• (*) Flue gas dampers shall be provided by the Manufacturer. Dampers shall have positive control in both directions and shall be operable from grade. Damper blades shall be mounted on hollow shafts supported by self–aligning, self–lubricating, carbon graphite sleeve bearings with flanged or pillow block mounting. Holes shall be provided on each shaft end and shaft center to allow free air flow through the shaft. Unless otherwise specified on the Data Sheet, the damper blades and shaft shall be 321 S.S. and the minimum disc thickness shall be 1/4 inch. Damper blades shall be welded to the shaft and shall be designed to provide for thermal expansion. An indicator corresponding to the damper travel shall be furnished to show the position of the damper and shall be visible from grade.
• All hot ducting from which heat shall be recovered shall have:
• Cold face temperature and heat loss calculated per this Practice
• Seal welded or bolted and gasketed construction
• Expansion joints equipped with an external air–tight flexible seal
• Refractory installed per EP 11–1–1
• (*) Plenum chambers, windboxes or noise muffling devices around burners shall be designed to permit access to the burners, pilots, and ignitors. These designs shall be submitted for approval by the Owner’s Engineer.
• Combustion air ducting shall:
• Be above ground
• Provide uniform flow distribution to all burners
• Be sized to limit the dynamic head in the distribution duct, at the point of maximum velocity, to no more than five percent of the burner pressure drop at the design firing conditions

• Be suitable for discharge pressure of the fan at the minimum specified design air temperature and maximum fan speed
• For forced draft fans operating in parallel, the discharge dampers shall be equipped with pneumatic operators, and be capable of tight shut–off to prevent back–flow through any non– operating fan.
• A means shall be provided in combustion air ducts to individual forced– draft burners to cut off air supply during burner outage.
• Ducting for flue gas and air shall be of continuous seal–welded construction to insure air tightness with bolted and gasketed flanged connections for field assembly. Ducts shall be reinforced and stiffened for the operating air pressure and temperature under all conditions within the guaranteed operation. The maximum unstiffened areas of flat casing shall be no more than 3 feet by 5 feet.
• The minimum thickness of flue gas duct casing shall be 1/4 inch.
• The minimum thickness of air duct casing shall be 3/16 inch.
• (*) Expansion joints in ducting shall be designed to prevent excessive forces on the boiler, preheater and fans, shall be equipped with an air tight flexible seal, and shall be furnished by the Manufacturer. Designs shall be submitted to Purchaser for approval by the Owner’s Engineer.
• If more than one boiler exhausts to the same stack, isolation dampers shall be provided in the exhaust duct work of each boiler. The dampers shall be designed for tight shutoff and shall be braced sufficiently to withstand the maximum forced–draft fan discharge pressure at the maximum operating temperatures.
• Forced Draft Fan
• The draft fan shall operate with minimum noise and vibration over the entire operating range of the boiler and shall be in accordance with EP 6–6–1. The fan blade design shall be of either the airfoil or the backward curved, non–overloading type.
• The boiler shall be equipped with a constant speed, centrifugal type, draft fan operating at not more than 1200 rpm.
• Fan capacity and head shall provide at least the following safety factors:
• CFM = (Net CFM at 15% excess air) + 20%
• Static = (Burner drop plus Other air Resistance) x 130%
• Ambient temperature = 105 °F
• The fan design shall take into account the design relative humidity and altitude at the site of installation.
• The fan shall be equipped with inlet screen, all necessary cleanout doors, bearings, pedestal and supports.
• A steel duct shall be provided between the draft fan and windbox.
• (*) Fans will be steam turbine driven or electric motor driven and shall be in accordance with the specified power and steam conditions. When turbine driven fans are specified, they shall be in compliance with EP 6–3–1 and EP 6–5–1.

• (*) The driver size and start–up and operating procedures shall be reviewed by the Owner’s Engineer to prevent overloading or over sizing of the driver at the extreme conditions.
• Main Burners
• Burners shall meet one of the following:
• A burner that has been commercially proven in comparable service (service conditions, fuel, orientations, turndown, excess air and heat release).
• (*) A demonstration of the burner being proposed under simulated field conditions to the satisfaction of the Owner’s Engineer.
• Dual fuel burners shall:
• (*) Be supplied when specified by the Owner.
• (*) Be capable of firing the gas and liquid fuels specified, both separately and simultaneously.
• (*) Be dual rated; i.e., must be capable of meeting the design requirements on each fuel, fired separately, if specified on the Data Sheet.
• Have dual air controls arranged to provide proper air mixing under any firing mode.
• Have oil/gas guns so arranged that neither overheats the other, whether in service or out. If guns are not so arranged, they shall be provided with automatic retraction devices to remove them to a safe location immediately after shut off.
• An aspirating type air interlock shall be furnished for liquid fuel guns in pressurized units to prevent removal of an oil gun, if the seal air is not turned on. The seal air must be sufficient to prevent furnace gases from blowing out through the oil gun barrel hole.
• Oil guns must be easily removable, repairable, and replaceable, with the boiler in operation.
• Gas guns must be easily replaceable with the boiler in operation. Center fired gas guns shall be made retractable.
• Burners shall be capable of operating at 130 percent of the theoretical air requirements for complete combustion when firing the following normal design heat release without flame impingement:
• Up to five burners - 125% of normal design capacity
• Six or seven burners - 120% of normal design capacity
• Eight or more burners - 115% of normal design capacity
• Burners shall be capable of automatic start–up and of going from 0% output to 120% of design in a minimum time period under an automatic steam pressure control system.
• The Manufacturer shall define the minimum gas/oil rate required to maintain a burner flame under maximum velocity conditions across the burner.
• Burners shall be supported from the furnace structure.
• (*) Air registers must be accessible for air adjustments. The air register design shall be approved by the Owner’s Engineer. All parts of the burner register shall be shielded from burner radiation and protected against conducted heat.
• Burner blocks shall be suitable for a service temperature of 3000°F and shall be laid in high bonding cement. They shall be provided with one inch minimum expansion space filled with compressible insulation so that the burner block will be free to expand and contract as a unit.

• Liquid fuel burner atomizers and tips shall be of the following materials:
• Internal atomizers and tips shall be nitrided nitralloy or equivalent, and shall have a 0.01 inch case hardness of 1000 DPN (Diamond Pyramid N Scale).
• Tips shall be high speed tool steel (18–4–1, W–Cr–V, or equivalent), hardened to 55 Rockwell C.
• The distance from the burner to the nearest tube in direction of throw shall be at least 0.35 feet/ million Btu/hour, plus five feet.
• (*) Actual flow rates of all burner guns shall be within ± 5% of design. Calibration shall be witnessed by an Owner’s representative and a tabulation of the exact flows shall be provided.
• Two optical flame scanners shall be provided per each burner assembly.
• All burner hardware, including but not limited to, piping, tubing, flexible metal hose, shut off valves, and cocks, shall be of steel or steel alloys. Cast iron, copper alloys, aluminum alloys and similar such materials are not permitted.
• Burners shall be located to minimize exposure to furnace radiation. Burner parts which are exposed to furnace radiation shall be of heat resisting alloy.
• Pilots
• All burners shall have interrupted pilots. Individual gas pilots shall have a 3/32 inch minimum size gas orifice and be designed to operate within a range of 3 to 15 psig gas pressure. Pilots shall be “blow–out–proof” while maximum combustion air is blowing through the main burner throat and the main fuel is shut off.
• Pilot air shall be ducted from a point upstream of the individual burner shutoff darnper.
• Pilots shall be removable while the burner is in operation without dismantling burner ducting or plenum. A separate pilot shall be provided for each burner.
• Flame–front–type igniters are preferred.
• All igniters must be removable, repairable, and reinstallable with the burner in operation.
• Sootblowers
• Sootblowing facilities shall be selected per the criteria shown in Table 3.
• Sootblowers shall conform to EP 8–2–2.
• For finned tubes, sootblowers shall be arranged with longitudinal center lines parallel to tube center lines, if specified.
• The minimum distance between the lance O.D. and the tube O.D. (including extended surface) shall be six inches.
• Erosion protection of convection section side walls and end tube sheets shall be provided for the entire height of the convection section when sootblowers are used, or when space is provided for future sootblowers. The following materials are acceptable for providing erosion protection:
• Regular type, high–duty fire–clay brick
• Dense castable refractory, 130 pounds/cubic feet (min.), 3 inches thick

• The sootblower entrance ports shall be protected with AISI Type 310 stainless steel sleeves, 1/8 inch thick.
• Instrument and Controls
• The boiler shall be arranged for fully automatic operation, of the full modulation type and shall be provided with all safety devices required by the Insurance Association noted. Approval of the Insurance Association shall be obtained by the Manufacturer. The instrumentation and controls shall be in compliance with EP 12–1–1 and EP 12–2–1.
• The Manufacturer shall furnish an averaging pitot tube for air flow measurement.
• The Manufacturer shall provide level gauge glasses for the steam drum, including the temporary level gauges (used during boilout) which shall be Diamond Fiber Optic remote boiler gauge display type, or approved equal. A low water level switch shall also be included.
• All field devices (transmitters, control valves, gauges, etc.) will be procured directly by the Owner rather than the Manufacturer.
• Power Supply

The available power supply characteristics shall be as noted.

• Electrical Equipment and Wiring
• Equipment and wiring shall be furnished and installed in accordance with the Underwriter’s Laboratories requirements. Oil, heat, and moisture resistant wiring, #14 BWG minimum, shall be used throughout. All wiring shall be checked for grounds, shorts, and continuity. Safety control circuits shall be two (2) wire, one side grounded, preferable not exceeding nominal 120 volt, and shall be protected with suitable fuses or circuit breakers.
• Switching contacts shall be in the “hot” ungrounded lines. All wiring furnished by the Manufacturer shall terminate on terminal blocks.
• Motors

Motors with couplings and guards shall be furnished and mounted by the Manufacturer. Motors shall be in accordance with EP 13–3–1 and EP 13–3–2. Completed Data Sheets from EP 13– 3–1DS or EP 13–3–2DS shall be provided.

• Painting

All equipment shall be thoroughly cleaned, primed and given a shop coat of first quality heat and rust resistant paint before shipment and shall be in compliance with EP 10–3–1.

TESTING, INSPECTION, AND COMMISSIONING

• Equipment Test
• Motor testing shall be as stipulated in EP 13–3–1.
• After erection of the casing, the tightness of the inner casing shall be shop tested at a pressure not less than 10 inches H2O. Any leaks shall be eliminated by the Manufacturer.
• A performance test of forced and induced draft fans is required if the Manufacturer’s prototype has not been tested per the AMCA 210 Test Code using the test set–up specified by the code most similar to the actual installation.

• (*) All instrument process piping and air piping shall be leak tested. All tests shall be witnessed by the Owner’s Engineer.
• Hydrostatic Test
• (*) The Inspector shall be notified 5 working days prior to the day the hydrotest is to be made. Should repairs be required, the Inspector’s approval must be obtained regarding the extent of any required repairs.
• Should repairs be required, the hydrotest shall be repeated after completion of the repairs.
• Inhibited water shall be used for hydrotesting in areas where the water is brackish or contains impurities which might corrode the boiler.
• The hydrostatic test shall be based on the maximum allowable working pressure (MAWP) and the associated working temperature at which the MAWP applies.
• The hydrostatic test shall be performed by the Manufacturer in accordance with the ASME Boiler Code and shall be certified by the Owner’s approved insurance company.
• The gaskets used during the hydrostatic test shall be discarded. New gaskets shall be supplied with the boiler.
• Performance Test
• (*) As soon as possible after satisfactory commissioning, the performance of the boiler shall be tested to determine if it meets with the specified requirements. The test conditions shall be agreed upon by the Owner’s Engineer and the Manufacturer.
• (*) The performance test will be performed by the Owner’s Engineer. The Manufacturer will be able to provide a participant–observer for the test.
• The test shall be made in accordance with the latest edition of the ASME Test Code for stationary steam generating units (PTC 4.1 and PTC 19.11), and the measure of performance shall be the results of such tests.
• Steam and water properties used in the test calculations shall be based on the steam tables in the latest edition of “Thermodynamic Properties of Steam” by Keenan and Keyes.
• Inspection
• (*) All materials and fabrication are subject to inspection by the Inspector. Rejections by the Inspector are final; however, the Inspector’s inspection and/or witnessing of the specified tests does not relieve the Manufacturer of conforming to this Practice, or from the materials, apparatus, workmanship or performance guarantees. Waiver of any phase of the inspection must be obtained from the Owner’s Engineer.
• The Manufacturer shall advise the Inspector (as directed in the Purchase Order) at least five (5) working days before fabrication is to begin, and at least five (5) working days before the equipment and/or parts are to be completed, and/or the specified testing is to be performed, and/ or preparation for shipment will be completed, whichever of these stages will provide the Inspector with the best opportunity to carry out final inspection, and/or witness the specified testing.

• Commissioning

• (*) The Owner may require the Manufacturer to supply field supervision during commissioning of the boiler. This may include installation, field inspection, start–up and performance troubleshooting.
• (*) This experienced supervision will either be supplied at a “per diem” price, plus travel and living expenses, or as a lumped sum, with the days of allowed service noted. The Data Sheet shall specify which is required.
• The Manufacturer will supply a copy of his field supervision contract, and either the current “per diem” rate with his quotation, or the lumped sum allowance included in the quotation.
• If required, field supervision paid via “per diem” contract will be ordered separately.
• Field supervision during commissioning shall include:
• Dryout, boil out, preliminary operation, and instruction of operating personnel
• Initial operation and adjustment of burners and flame safe guard system
• Operation and adjustment of draft fan(s)

DRAWINGS AND DATA REQUIREMENTS

The number of copies of drawings and data books to be supplied are specified on the Packaged Watertube Boiler Data Sheet, EP 8–3–1 DS.

• Quotation Data

The Manufacturer shall provide the following data with his quotation.

• A completed Packaged Watertube Boiler Manufacturer Supplied Data Sheet with the Manufacturer’s quotation information.
• A detailed list of any deviations or exceptions to this Practice.
• Descriptive literature including outline dimensions and weights of major equipment.
• Descriptive literature, including materials of construction, of each item of equipment supplied.
• A schematic flow diagram showing all items of equipment, and instruments, etc., is to be supplied by the Manufacturer.
• Suggested plot layout of boiler.
• (*) Detailed list of vendors for equipment, valves, and trimmings to be furnished, for the Owner’s Engineer’s review and approval.
• A curve showing expected superheated steam temperatures from 25% load to 100% load.
• Predicted performance data at 25%, 50%, 75%, and 100% of design steam load.
• Details of steam purifying apparatus.
• Drawings that show the proposed fire side location of future soot blowers.
• Instruments shall be listed separately in the quotation and shall be priced separately.
• Equipment or features included but not necessarily specified.
• Priced list of normally recommended spare parts. This data will be used in bid evaluations.
• Data Following Purchase Order

Within six (6) weeks of receipt of the Purchase Order, the Manufacturer shall provide the following:

• (*) Outline drawings for approval, showing all locations and sizes for connections and anchor bolts. The number of drawings required is shown on the Data Sheets.
• Complete definition of the field work required by others to install the boiler at the job site.
• Bills of material, to include all instruments and valves with complete model numbers.

• Foundation and structural steel requirements.
• Point of connection of any wiring, piping, and duct work by others.
• Equipment wiring diagrams.
• System wiring schematic in simple ladder diagram format. Include internal logic of flame controller and safety cut out devices in ladder diagram.
• Data Following Drawing Approval

At least two months prior to the shipment of the boiler, the Manufacturer shall supply:

• Complete equipment manuals. These manuals will include installation, operation, and maintenance directions and data.
• Detailed specifications and instruction manuals for all accessories.
• Specific operating instructions.
• Certified drawings.
• Index of controls – Cross reference tag number with model number and Manufacturer and electrical wiring drawing number.

SPARE PARTS

• Within six weeks of receipt of the Purchase Order, the Manufacturer shall provide a complete list of recommended spare parts. This list will be based on the total purchase order.
• The complete spare parts list shall include parts location diagrams or drawings.
• The Manufacturer shall supply a listing of spare parts. This list will be based on the total purchase order.

SHIPPING

• Preparation for shipment shall be in accordance with the Manufacturer’s standards and as noted herein. The Manufacturer shall be solely responsible for the adequacy of the “Preparation for Shipment” provisions employed with respect to materials and applications to prevent damage when handled by commercial carrier systems.
• The boiler shall be thoroughly cleaned inside and outside and shall be free from grease, weld splatter, scale, slag, rust, and all foreign matter. Only stainless steel grit, or clean, iron–free sand shall be used to clean stainless steel surfaces.
• Flange faces and machined surfaces shall be cleaned and coated with a heavy corrosion preventative waterproof grease.
• Prior to sealing of the openings, desiccant bags shall be distributed in the vessels for temporary corrosion protection and the number of bags installed shall be plainly indicated on the outside of the vessel.
• Flange faces shall be protected with 3/4 inch thick full face plywood or 1/4 inch thick metal covers with four full diameter bolts and rubber gaskets, or with plastic flange covers made by Klipper Mfg., Bellaire, Texas. The cover and flange shall be taped for waterproof protection.
• Couplings shall be protected by steel pipe plugs. All other openings shall be plugged to prevent damage during shipment.
• All threads of bolts including exposed parts shall be coated with a metallic base waterproof lubricant to prevent galling in use and aqueous corrosion during testing, shipping, and storage.

• After final inspection and testing, but before shipment, one coat of inhibited red primer shall be applied to all exposed ferrous surfaces. No painting shall be done unless surfaces are above 40°F.
• The boiler shall be shipped completely assembled and shall be clearly identified with the equipment number painted or dye stencil led in a conspicuous location.
• Bracing, supports, and rigging shall be provided to prevent any damage during shipping, lifting, or unloading. This material will be painted yellow to indicate it is to be removed prior to operation.
• The boiler shall be shipped to the destination noted on the Data Sheet.
• Specific shipping directions shall be provided after a Purchase Order is issued.

GUARANTEE

• Process Guarantee

The following performance guarantees, at design conditions, shall be included:

• Maximum continuous steam flow.
• Efficiency - The conditions at which efficiency is guaranteed shall be specified by the Manufacturer, including:
• Feedwater temperature
• Excess air leaving boiler and up the stack
• Gas temperature leaving boiler and up the stack
• Blowdown rate
• Fuel
• Allowance due to margin or error in design and inaccuracy in testing (maximum one percent)
• Superheater pressure drop (plus or minus ten percent).
• Steam temperature leaving the superheater (plus or minus 10°F). If steam temperature control equipment is furnished, this equipment shall be guaranteed for a specified load and temperature range.
• (*) Steam purity leaving the steam drum. Solids content of steam shall not exceed 1 ppm with solids concentration in the boiler as specified in Table 4 for the operating pressure. If the drum water is at another solids level, the actual steam solids shall be taken as the measured solids multiplied by the ratio of actual drum solids/solids value in Table 4. The effect of any external purifier supplied at the Owner’s request shall not be considered in determining this value of steam purity.
• If an air heater is provided, the temperature of the air leaving the air heater ± 25°F.
• If an economizer is provided, the pressure drop between the economizer inlet and the steam drum (plus or minus 10 percent).
• Pressure drop across the stop and non–return valves in the superheater outlet.
• Gas side pressure drop, inches WC, through the entire boiler.
• Emission requirements per IPE Engineering Services Recommended Environmental Guidelines.
• Noise level requirements per IPE Engineering Services Recommended Environmental Guidelines.

• Performance Guarantee

The Manufacturer shall guarantee that the boiler will perform in accordance with the purchase specifications at the design rate for a period of one year after start–up (performance items are listed in Table 1). Major criteria shall be actual pinch–point performance and stack temperature. Should the boiler fail to meet the guaranteed performance at any one time within that period, the Manufacturer shall, at the Owner’s option, do one of the following:

• At his expense, and in the minimum practical time, and at the time needed, make all necessary replacements and repairs to place the problem areas in a state of proper materials and correct workmanship and do any other work required to assure that similar areas are in the same good condition.
• Reimburse the Owner for actual costs of doing the above.
• Mechanical Guarantee

The Manufacturer shall guarantee all material and workmanship for a minimum period of one year after acceptance by the Owner, not to exceed 18 months after completion. In the case of a boiler bought with a Design Specification, the Owner assumes the responsibility for that portion of the design included in the Design Specifications. Should any part of the boiler fail within that period from a cause resulting from workmanship, the Manufacturer shall, at the Owner’s option, do one of the following:

• At his expense, and in the minimum practical time, and at the time needed, make all necessary replacements and repairs to place the problem areas in a state of proper materials and correct workmanship and do any other work required to assure that similar areas are in the same good condition.
• Reimburse the Owner for actual costs of doing the above.

CERTIFICATION

• The Manufacturer shall be in possession of an ASME S stamp and a valid certification of authorization to affix it to all parts as required by the ASME Code, Section I.
• The boiler erector, if different from the Manufacturer, shall also be in possession of an ASME S stamp, if applicable, and a valid certificate of authorization to affix it as required by the ASME Code, Section I.
• The Manufacturer shall furnish the Owner with;
• Five original completed Partial Data Reports, ASME Code forms, signed by National Board Inspectors, on all parts of the boiler as required by Code. These reports shall be forwarded to the Owner’s Engineer at the time of shipment of the applicable parts.
• Five original completed Code Form P–3, signed by a National Board Inspector, on completion of boiler installation.
• Five copies of the Manufacturer’s certified mill test data on all pressure materials not permanently identified with ASME material markings by their suppliers, as required by ASME Section I.
• The Manufacturer shall register the boiler with the National Board of Boiler and Pressure Vessel Inspectors.

13.0 TABLES

TABLE 1

PERFORMANCE CRITERIA

TABLE 2

MAXIMUM HEAT RELEASE BASED ON HHV

TABLE 3

SOOTBLOWER SELECTION CRITERIA

NOTE: If using a combination oil–gas burner, the properties of the oil shall govern selection of the cleaning facilities.

TABLE 4 STEAM PURITY

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