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11-01-17

23 50 11 - 1

SECTION 23 50 11

BOILER PLANT MECHANICAL EQUIPMENT

PART 1 - GENERAL

1.1 DESCRIPTION

A. Feedwater deaerator, condensate and boiler feed pumps, condensate storage tank, compressed air systems, blowoff tank, blowdown heat recovery, chemical treatment systems, steam vent silencer, and other equipment that supports the operation of the boilers.

B. A complete listing of common acronyms and abbreviations are included in

Section 23 05 10, COMMON WORK RESULTS FOR BOILER PLANT AND STEAM

GENERATION.

1.2 RELATED WORK

A. Section 01 00 00, GENERAL REQUIREMENTS.

B. Section 01 33 23, SHOP DRAWINGS, PRODUCT DATA, AND SAMPLES.

C. Section 01 81 13, SUSTAINABLE CONSTRUCTION REQUIREMENTS.

D. Section 01 91 00, GENERAL COMMISSIONING REQUIREMENTS.

E. Section 09 91 00, PAINTING.

F. Section 13 05 41, SEISMIC RESTRAINT REQUIREMENTS FOR NON-STRUCTURAL

COMPONENTS.

G. Section 23 05 10, COMMON WORK RESULTS FOR BOILER PLANT AND STEAM

H. Section 23 05 51, NOISE AND VIBRATION CONTROL FOR BOILER PLANT.

I. Section 23 07 11, HVAC AND BOILER PLANT INSULATION.

J. Section 23 08 00, COMMISSIONING OF HVAC SYSTEMS.

K. Section 23 08 11, DEMONSTRATIONS AND TESTS FOR BOILER PLANT.

L. Section 23 09 11, INSTRUMENTATION AND CONTROL FOR BOILER PLANT.

M. Section 23 09 23, DIRECT-DIGITAL CONTROL SYSTEM OR HVAC.

N. Section 23 21 11, BOILER PLANT PIPING SYSTEMS.

O. Section 26 29 11, MOTOR CONTROLLERS.

1.3 APPLICABLE PUBLICATIONS

A. The publications listed below form a part of this specification to the extent referenced. The publications are referenced in the text by the basic designation only. Where conflicts occur these specifications and the VHA standard will govern.

B. American Society of Mechanical Engineers (ASME):

B16.34-2013.............Valves Flanged, Threaded and Welding End

PTC 12.3-1997...........Performance Test Code on Deaerators

23 50 11 - 2

ASME Boiler and Pressure Vessel Code – BPVC Section

VIII-2015..........Rules for Construction of Pressure Vessels, Divisions 1 and 2

C. American Society for Testing and Materials (ASTM):

A53/A53M-2012...........Standard Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-Coated, Welded and

Seamless

A106/A106M-2015.........Standard Specification for Seamless Carbon

Steel Pipe for High Temperature Service

A234/A234M-2015.........Standard Specification for Piping Fittings of

Wrought Carbon Steel and Alloy Steel for

Moderate and High Temperature Service

A285/A285M-2012.........Standard Specification for Pressure Vessel

Plates, Carbon Steel, Low- and Intermediate–

Tensile Strength

A414/A414M-2014.........Standard Specification for Steel, Sheet, Carbon, and High-Strength, Low-Alloy for

Pressure Vessels

A515/A515M-2010 (R2015).Standard Specification for Pressure Vessel

Plates, Carbon Steel, for Intermediate- and

Higher-Temperature Service

A516/A516M-2010 (R2015).Standard Specification for Pressure Vessel

Plates, Carbon Steel, for Moderate- and Lower-

Temperature Service

D. Environmental Protection Agency (EPA):

CFR 40, 264.193-2014....Containment and Detection of Releases

E. Department of Health and Human Services, Food and Drug Administration

(FDA):

CFR 21, 175.300-2015....Resinous and Polymeric Coatings

F. Society for Protective Coatings (SSPC):

SP 5-2007...............White Metal Blast Cleaning

G. Underwriters Laboratories (UL):

574-2003 (R2014)........Standard for Electric Oil Heaters

H. Department of Veterans Affairs (VA):

PG-18-10-2016...........Physical Security and Resiliency Design Manual

VHA Boiler Plant Safety Devices Testing Manual, Third Edition

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1.4 SUBMITTALS

A. Submittals, including number of required copies, shall be submitted in accordance with Section 01 33 23, SHOP DRAWINGS, PRODUCT DATA, AND

SAMPLES.

B. Information and material submitted under this section shall be marked

“SUBMITTED UNDER SECTION 23 50 11, BOILER PLANT MECHANICAL EQUIPMENT”,

with applicable paragraph identification.

C. Manufacturer's Literature and Data including: Full item description and optional features and accessories. Include dimensions, weights, materials, applications, standard compliance, model numbers, size, and capacity.

D. Feedwater Deaerator with Storage Tank and Accessories:

1. Drawings showing arrangement and overall dimensions of feedwater deaerator including storage tank. Show locations of tank-mounted devices. Show locations and sizes of pipe connections and access openings. Show design of all shell, head and nozzle welds. Show access platforms as required for all maintenance and inspection points.

2. Weight of entire assembly empty and flooded.

3. Catalog data, drawings and specification sheets showing design and construction of feedwater deaerator, storage tank, recycle pumps, water flow control valves, safety valve, overflow control valve, water level and overflow control systems, vent orifice, vacuum breaker, alarm switches and all accessories.

4. Design flow capacity, oxygen removal rate, and other performance data and pressure and temperature limitations of feedwater deaerator, recycle pumps, water flow/level control valve and control system, safety valve, overflow control valve, vent orifice, vacuum breaker, alarm switches and all accessories, to include lockout/tagout points.

5. Catalog data on oxygen test kit.

6. Oxygen sample and chemical feed probe design.

7. Deaerator inlet pressure requirements - steam and water.

8. Packaged feedwater deaerator/feedwater pump units: Boiler feedwater pump suction and discharge pipe sizing and arrangement. Design of support framework and access platforms. Pumps shall have a minimum of 762 mm (30 inches) center to center clearance and 1800 mm (6 foot) clearance above pumps. Any one pump/motor combination shall be

23 50 11 - 4 removable without disassembly of any other pumps or components.

Provide lifting attachments as required to rig pump assemblies out of frame of the assembly.

9. Seismic Restraint Data: Seismic design of support framework for packaged system. Refer to Section 13 05 41, SEISMIC RESTRAINT

REQUIREMENTS FOR NON-STRUCTURAL COMPONENTS.

E. Condensate Storage Tank and Accessories:

1. Drawings showing arrangement and overall dimensions of tank and supports. Show locations and sizes of all pipe connections and access openings. Access platforms as required for maintenance and inspections and operation of the equipment or parts thereof.

2. Weight of entire assembly empty and flooded.

3. Design and construction (including pressure and temperature limitations) of tank, continuous blowdown heat exchanger (if provided), control valves, water level control system, level alarm switches and all accessories, to include lockout/tagout points.

4. Performance data on control valves and continuous blowdown heat exchanger (if provided). Refer to drawings (Schedules) for requirements.

5. Interior Coating: Material specification, service limitations, instructions for application, experience record under the required service conditions.

F. Blowoff Tank and Accessories, Flash Tank:

1. Drawing showing outline dimensions, arrangement and weight of tank and accessories. Locations and sizes of all pipe connections and access openings.

2. Design and construction of tank, supports and accessories.

3. Design and performance of blowoff tank temperature control valve.

G. Boiler Feed and Condensate Transfer Pumps:

1. Drawings with dimensions of assemblies of pumps and drivers.

2. Catalog data and specification sheets on design and construction of pumps, drivers and couplings (flexible-coupled units).

3. Motor efficiency and power factor at full load.

4. Performance curves showing discharge head, required flow plus recirculation, net positive suction head required, efficiency, driver power, impeller diameter to be furnished. Refer to drawings for requirements.

5. Pressure and temperature limitations of pump unit and accessories.

23 50 11 - 5

6. Size and capacity of recirculation orifice.

7. Data on variable frequency drive (VFD) units and pressure controllers (if VFD specified).

H. Condensate Return Pumps (Electrical and/or Mechanical Types) and Vacuum

Heating Pump Units:

1. Drawings with dimensions of entire unit. Drawing shall include locations and sizes of all pipe connections.

pumps, receiver and accessories.

3. Catalog cuts and schematic diagram of controls.

4. Electric pump performance curves showing discharge head, flow, net positive suction head required, efficiency, motor power and impeller diameter to be furnished. Mechanical pump performance showing discharge head, flow, required inlet head and steam pressure. Refer to drawings for requirements.

5. Pressure and temperature limitations of pump unit.

I. Boiler Water and Deaerator Water Sample Coolers:

1. Drawings with dimensions, and sizes and location of piping connections.

2. Catalog data and specification sheets on the design and construction.

3. Pressure and temperature limitations.

4. Amount of heat exchange surface.

J. Automatic Continuous Blowdown Control System:

1. Drawings with arrangement and dimensions of entire unit. Include locations and sizes of all pipe connections.

conductivity sensor, control valves, controller.

3. Performance data on control valves.

4. Pressure and temperature limitations of valves and conductivity sensor.

K. Test Data – Acceptance Tests, on-site: Four copies all specified tests.

L. Complete operating and maintenance manuals including wiring diagrams, technical data sheets, information for ordering replacement parts, and troubleshooting guide:

1. Include complete list indicating all components of the systems.

2. Include complete diagrams of the internal wiring for each item of equipment.

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3. Diagrams shall have their terminals identified to facilitate installation, operation and maintenance.

M. Completed System Readiness Checklist provided by the Commissioning

Agent and completed by the contractor, signed by a qualified technician and dated on the date of completion, in accordance with the requirements of Section 23 08 00, COMMISSIONING OF HVAC SYSTEMS.

N. Submit training plans and instructor qualifications in accordance with the requirements of Section 23 08 00, COMMISSIONING OF HVAC SYSTEMS.

1.5 AS-BUILT DOCUMENTATION

A. Submit manufacturer’s literature and data updated to include submittal review comments and any equipment substitutions.

B. Submit operation and maintenance data updated to include submittal review comments, VA approved substitutions and construction revisions shall be in electronic version on CD or DVD and inserted into a three-ring binder. All aspects of system operation and maintenance procedures, including applicable piping isometrics, wiring diagrams of all circuits, a written description of system design, control logic, and sequence of operation shall be included in the operation and maintenance manual. The operations and maintenance manual shall include troubleshooting techniques and procedures for emergency situations.

Notes on all special systems or devices shall be included. A List of recommended spare parts (manufacturer, model number, and quantity) shall be furnished. Information explaining any special knowledge or tools the owner will be required to employ shall be inserted into the

As-Built documentation.

C. The installing contractor shall maintain as-built drawings of each completed phase for verification; and, shall provide the complete set at the time of final systems certification testing. Should the installing contractor engage the testing company to provide as-built or any portion thereof, it shall not be deemed a conflict of interest or breach of the ‘third party testing company’ requirement. Provide record drawings as follows:

1. Red-lined, hand-marked drawings are to be provided, with one paper copy and a scanned PDF version of the hand-marked drawings provided on CD or DVD.

D. The as-built drawings shall indicate the location and type of all lockout/tagout points for all energy sources for all equipment and pumps to include breaker location and numbers, valve tag numbers, etc.

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Coordinate lockout/tagout procedures and practices with local VA

E. Certification documentation shall be provided to COR 21 working days prior to submitting the request for final inspection. The documentation shall include all test results, the names of individuals performing work for the testing agency on this project, detailed procedures followed for all tests, and provide documentation/certification that all results of tests were within limits specified. Test results shall contain written sequence of test procedure with written test results annotated at each step along with the expected outcome or setpoint. The results shall include all readings, including but not limited to data on device (make, model and performance characteristics), normal pressures, switch ranges, trip points, amp readings, and calibration data to include equipment serial numbers or individual identifications, etc.

PART 2 - PRODUCTS

GENERAL

Electric motor control cabinets/enclosures including VFDs in the boiler plant shall be minimum NEMA 4 or better. The design AE shall determine at the design stage based on the environmental condition and location.

This shall also be indicated on the drawings.

2.1 FEEDWATER DEAERATOR WITH STORAGE TANK AND ACCESSORIES

A. Pressurized 14 to 35 kPa (2 to 5 psig) unit designed to heat and deaerate boiler feedwater by direct contact with low pressure steam.

Spray type deaerating section. Horizontal feedwater storage tank.

Provide recycle spray water pumps on spray-type units if necessary to obtain required performance. Provide accessories including vacuum breaker, safety valve, water inlet, steam pressure reducing valve and overflow controls and control valves, water level indicators and alarms and other devices as specified and shown.

B. Performance and Operating Characteristics:

1. Oxygen Content of Feedwater Output: 7 ppb maximum over turndown range with minimum and normal feedwater input temperatures as listed.

2. Turndown: 20/1.

3. Required Maximum Feedwater Flow Output: Shown on drawings.

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4. No carbon dioxide in feedwater output; maximum steam vent loss 1/2 percent of input steam at maximum load.

5. Feedwater Input Temperature: Minimum temperature is 15 degrees C (59 degrees F) and normal range is 60 to 82 degrees C (140 to 180 degrees F).

6. Water Pressure Loss Through Spray Valves: 48 kPa (7 psig) maximum.

7. Steam Pressure Loss in Unit: 6.9 kPa (1 psig) maximum.

C. Feedwater Storage Capacity to the Overflow Line: Sufficient for twenty minutes operation at maximum required feedwater output with no input water, unless shown otherwise on the drawings. Overflow line

(elevation) shall be set by feedwater deaerator manufacturer so that there is no water hammer when water is at this level.

D. Construction:

1. Storage Tank and Deaerator Pressure Vessels:

a. Conform to ASME BPVC Section VIII. Design for saturated steam at

345 kPa (50 psig) with 3.2 mm (0.125 inch) corrosion allowance.

b. Carbon steel, ASTM A285/A285M Grade C or ASTM A516/A516M Grade

70. Weld metal strength shall approximate the strength of the base metal. All welds shall be double-vee type. No single vee welds allowed. Weld undercuts are prohibited. All welding must be constructed to allow future internal weld inspections, utilizing non-destructive-testing methods.

c. Post Weld Heat Treatment (PWHT) to stress-relieve pressure vessel to 620 degrees C (1148 degrees F) not to exceed ASME hold-time or temperature.

d. Provide 100 percent radiography of all longitudinal and circumferential welded seams. Test nozzle-to-shell welds by wet magnetic-particle method. Hydrostatically test final assembly at

1.3 times design pressure.

e. Furnish completed applicable ASME Forms U-1, U-1A or U-2.

f. Provide a sacrificial magnesium anode for cathodic protection against corrosion.

g. Provide a vacuum breaker.

2. Spray Valve Assemblies: Spring-loaded, guided stem, stainless steel and Monel, removable. Spring-loaded, guided stem types not required on spray-type units that operate with recycle pumps at constant flow rates through the spray valves.

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3. All other parts in deaerator section exposed to undeaerated liquids or gases must be constructed of stainless steel, cupro-nickel or equivalent.

4. Provide two 300 mm (12 inches) x 406 mm (16 inches) elliptical manways in storage tank, located below the normal water level, but near the tank centerline, and away from the deaeration section or internal piping. Manway locations must allow unrestricted access to tank interior with no interference from internal equipment and piping and with easy access from outside the tank. Second manway is to facilitate the annual internal inspections. Provide permanent access platforms as required.

5. Provide access openings in deaeration section to allow inspection and replacement of trays, spray valve assemblies, column packing.

6. Support: Steel saddles or legs welded to storage tank with minimum height to provide for the net positive suction head required of the pumps selected. Coordinate location with structural design of building.

7. Nameplates: Attach to bracket projecting beyond field-applied insulation. Provide all ASME pressure vessel nameplate information as required by the Code along with information identifying the designer and manufacturer of the storage tank and the deaeration section.

8. Pipe Connections:

a. Threaded for sizes 50 mm (2 inches) and under.

b. Flanged, 1035 kPa (150 psig) ASME, for sizes above 50 mm (2 inches).

c. Vortex breaker in boiler feedwater pump suction connection.

d. Overflow Pipe:

1) Overflow pipe inside tank terminating 150 mm (6 inches) below low-level alarm set point. Operation of overflow control system must not allow water level to fall to the level of the overflow pipe inlet.

2) Overflow pipe sizing, based on required maximum feedwater flow output of feedwater deaerator:

Feedwater

Flow Rate

(kg/sec)

Feedwater

Flow Rate

(klb/hr)

Overflow Pipe

Minimum Size

(mm)

Overflow Pipe

Minimum Size

(in)

0 to 3.8 0 to 30 75 3

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3.9 to 7.6 31 to 60 100 4

7.7 to 12.6 61 to 100 150 6

E. Steam Safety Valve: Mount on feedwater deaerator pressure vessel. Set pressure 103 kPa (15 psig). Capacity as shown. If not shown, minimum capacity 0.11 kg/sec (900 lb/hr). For safety valve construction requirements, refer to Section 23 21 11, BOILER PLANT PIPING SYSTEMS.

F. Oxygen and Non-Condensable Gas Venting: Straight vertical pipe extending through roof from deaeration section. Provide gate valve in vent pipe, with hole drilled in wedge. Hole size selected by feedwater deaerator manufacturer for normal venting with gate valve closed.

G. Thermometers and Pressure Gauges: Refer to Section 23 09 11, INSTRUMENTATION AND CONTROL FOR BOILER PLANT for construction requirements. Provide thermometers on deaeration section and on storage tank. Provide compound gauge with shut-off valve and siphon on deaerator.

H. Vacuum Breaker: Sized by deaerator manufacturer to protect unit. Bronze body construction with bronze internal trim, chemical resistant silicone seat disc and an atmospheric vent, rated for 1035 kPa (150 psig).

I. Water Sample and Chemical Feed Probes: Type 304 or 316 stainless steel, multi-ported, minimum length 300 mm (1 foot), accessible for removal from exterior of tank.

J. Dissolved Oxygen Test Kit: Provide a colorimetric-comparator type kit, utilizing Rhodazine D methodology, for use during acceptance testing and for future use by the VAMC. The kit shall include self-filling ampoules, color comparator, oxygen-resistant tubing, sampling devices, sealed glass ampoules containing reagent, carrying case, all equipment necessary for complete test. Range 0-20 ppb of dissolved oxygen.

K. Cleaning and Painting: Remove all foreign material to bare metal. Coat exterior of pressure vessel with rust-preventative primer. Refer to

Section 09 91 00, PAINTING. Do not coat interior of pressure vessel.

L. Seismic Design: Refer to Section 13 05 41, SEISMIC RESTRAINT

REQUIREMENTS FOR NON-STRUCTURAL COMPONENTS. Design the entire assembly and anchorage to building to resist seismic forces and be fully operational after the seismic event.

M. Water Level Indicators:

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1. Gauge Glasses: Red line type, overlapping glasses if multiple glasses are utilized. Provide automatic offset-type gauge valves that stop the flow if a glass is broken. Drain cock on lower gauge valve. Gauge glass protecting rods.

2. Vertical pipe type header shall be connected to top and bottom of storage tank with tank isolation valves and valved header drain.

Viewable gauges shall cover entire diameter of tank.

3. Minimum rating 121 degrees C, 200 kPa (250 degrees F, 29 psig).

N. Low Level Alarm Switch: Float type unit with magnetically actuated switch. Locate external to tank on a vertical header with valved tank connections and valved drain. Switch elevation shall be at the tank centerline. Minimum rating 121 degrees C, 200 kPa (250 degrees F, 29 psig). Provide signals to computer workstation specified in Section 23

09 11, INSTRUMENTATION AND CONTROL FOR BOILER PLANT.

O. High Level Alarm Switch and Overflow Control Switch:

1. Conductivity probe type electronic level switches providing relay contacts for separate high-level alarm operation and overflow control valve operation completely separate from control system for inlet water flow control valves. Overflow control valve shall automatically open when the water level rises approximately 100 mm

(4 inches) above the high-water alarm level. Provide high level and overflow signals to computer workstation specified in Section 23 09

11, INSTRUMENTATION AND CONTROL FOR BOILER PLANT.

2. The principle of operation shall be differential resistivity of steam and water at the operating temperatures and pressures. The system shall include electronics unit, electrodes, special cable between the electrodes and electronics unit, and electrode cover.

The unit shall be designed to fail safe.

3. Electronics Unit:

a. Each unit shall be capable for signal discrimination of two electrode channels.

b. Each electrode and its associated circuitry shall be powered by an independent power source. Power distribution system within the electronics shall be separate for each channel with its own transformer and shall be electrically isolated from other channels.

c. Input power 110 V, 60 Hz, single phase.

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d. All input power to each electrode shall be a low voltage, low frequency ac voltage. dc voltages are prohibited because this may cause electroplating at the electrodes.

e. The signal discrimination and fault detection system for each electrode channel shall be independent of the other channel and any fault in the electronics circuitry of one channel shall not be transferred to the other channel.

f. The system shall have a continuous on-line fault detection system. The following faults shall be detected: Electrode failure, contamination from dirt on electrodes, electrode open circuit failure, electrode cable short to ground, electrode cable ground sense failure, power source failure, any electronic component failure. Electronic circuitry not monitored by the fault detection system shall be provide with triple redundancy, where the circuit shall continue to operate and provide contact output with up to two component failures.

g. Faults shall be annunciated through separate NO and NC contacts.

h. The front of the unit shall have a LED display for each electrode channel indicating steam or water and status of each electrode.

i. NEMA 4 or better enclosure suitable for operating temperature of

-20 to 70 degrees C (-4 to 158 degrees F), with up to 100 percent relative humidity.

4. Electrodes:

a. Suitable for 121 degrees C, 200 kPa (250 degrees F, 29 psig) minimum. Material shall be stainless steel or better, smooth length threaded only allowed on end, and corrosion resistant.

b. Electrodes without gaskets are preferred.

c. Teflon insulator media.

d. Electrodes fitted into shrouded inserts which are directly welded onto the stand-pipe. Design to minimize faulty indication due to falling condensate into the electrodes.

5. Electrode Cable:

a. Pure nickel wires for at least the first two meters at the electrode end, with pure nickel crimps. PTFE insulation capable of withstanding up to 260 degrees C (500 degrees F).

b. Continuous cables from the electrodes to the electronic unit. No junction boxes allowed.

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P. Overflow Water Control Valve and Controller: Open-shut electric or electronic actuated overflow control valve actuated by conductivity probe-type water level sensor and control system.

1. Performance: When water level reaches the overflow level as set by the feedwater deaerator manufacturer, automatically open the overflow control valve to reduce the water level. Automatically close the overflow valve when the water level has been lowered to a point 100 mm (4 inches) below the high-level alarm set point. Valve operational speed shall not exceed 30 seconds for 90-degree valve movement.

2. Controller: Automatic control shall be from the high-level alarm and overflow control switch system. Provide a manual/auto switch on the main instrument panel that indicates valve position. Communicate valve position with computer work station. Control valve shall fail open. A limit switch on the valve actuator shall initiate alarm on control station and in computer work station when valve is open.

3. Control Valve:

a. High performance butterfly valve, double offset design.

b. Carbon steel 17-4PH steel valve body conforming to ASME B16.34, Class 150, lug style, 316 stainless steel nitrided disc.

c. Self-energizing TFE seat providing bubble-tight shut off service on vacuum and low pressure and pressure sealed for high pressures. Bi-directional seating.

d. Packing adjustable, chevron design with TFE seals.

e. 7 kPa (1 psig) maximum pressure loss at maximum flow rate (120 percent of peak deaerator capacity if valve flow and pressure drop is not scheduled).

4. Valve Actuator:

a. Control module shall accept direct digital control input 4-20 mA or 2-10 VDC from controller. Module to provide 4-20 mA output for feedback, terminal strip, and conduit entries for power and control wiring.

b. Torque output range shall be appropriate for the differential pressure and pressure and temperature conditions. Duty cycle: 50 to 75 percent. Actuator to fail leaving valve in open position.

c. Electric Motors: Totally enclosed, non-ventilated, high starting torque, reversible induction type, and Class F insulation.

d. Electrical Characteristics: As required for the application.

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e. Thermal Overload Motor Protection: Auto reset thermal switch embedded in the motor winding to trip when the maximum winding temperature is exceeded.

f. Resolution: 100 to 400 increments through 90-degree travel.

g. Power Gears: Alloy steel spur gears to final stage aluminum bronze worm sector gear.

h. Bearings: High quality alloy steel sleeve and ball bearings.

i. Housing: NEMA 4 or better, water tight, corrosion-resistant, robust aluminum die cast.

j. Equip with two SPDT auxiliary switches, visual position indicator, manual override handle adjustable mechanical stops.

k. Ambient temperature range: -35 to 66 degrees C (-31 to 150 degrees F).

Q. Storage Tank Automatic Water Level Controls:

1. Separate electric or electronic actuated modulating water inlet flow control valves for normal condensate transfer water and for emergency soft water makeup. Actuated by dedicated electronic controller with input signals from water level transmitter.

Manual/auto control capability.

2. Performance: Maintain a constant water level, plus or minus 25 mm (1 inch), in the feedwater deaerator storage tank by controlling the flow of condensate transfer water to the deaerator. Normal water level 200 mm (8 inches) below the overflow level. If water level falls to 100 mm (4 inches) below low water alarm setpoint, automatically operate the emergency soft water makeup valve to bring the water level to 100 mm (4 inches) above low water alarm setpoint.

3. Water Level Transmitter and Controller: Transmitter shall have programmable electronics, sealed diaphragms, direct sensing electronics, no mechanical force or torque transfer devices, external span and zero adjustment. Controller shall have proportional plus reset control, adjustable proportional band, reset rate and level set points. Provide manual-automatic control station on main instrument panel. Control station shall indicate actual water level, normal and emergency level set points and valve positions. Provide same indicating and control features on computer workstation specified in Section 23 09 11, INSTRUMENTATION AND

CONTROL FOR BOILER PLANT. If new boiler combustion controls are

23 50 11 - 15 furnished as part of this contract, the water level controller shall be the same make and model as the combustion controls.

4. Condensate Transfer and Soft Water Flow Control Valves and

Actuators:

a. Electric or electronic actuated, globe style.

b. Bronze or cast-iron bodies, threaded ends for pipe sizes 50 mm (2 inches) and under rated at 1725 kPa (250 psig), ASME flanged ends for pipe sizes over 50 mm (2 inches) rated at 850 kPa (123 psig) or 1035 kPa (150 psig).

c. Replaceable Type 316 stainless steel plugs and seats. RTFE seal for bubble-tight shut off. Linear flow characteristics.

d. Flow pressure loss 35 kPa (5 psig) maximum at maximum deaerator output.

e. Electric or electronic type actuator that accepts input of 4-20 mA or 2-10 VDC signal from controller.

f. Electronic positioner with 4–20 mA dc control output feedback.

Mounted integral with actuator. Digital positioner with capability to self-calibrate. Maintenance diagnostic data retained in memory. Design for 121 degrees C (250 degrees F) continuous service.

R. Steam Pressure Reducing Valve (PRV)

1. Provide steam pressure reducing valve sized to meet load requirements. PRV station shipped loose and installed by mechanical sub-contractor as shown on drawings. Refer to SECTION 23 21 11

BOILER PLANT PIPING SYSTEMS and Project Drawings for PRV

2.2 CONDENSATE RETURN TANK AND ACCESSORIES

A. Horizontal cylindrical welded steel tank, including accessory equipment, suitable for rigging into the available space. Comply with overall dimensions and arrangement of the tank and accessories shown on contract drawings. Accessories include make-up water controls and control valves, thermometer, water level gauge, and other devices as specified.

B. Service: Receiving and storing steam condensate and make-up water. Vent the tank to the atmosphere. Contents of tank may vary in temperature from 4 to 100 degrees C (40 to 212 degrees F).

C. Construction:

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1. Construct tank and appurtenances in accordance with ASME BPVC

Section VIII. Tank shall have cylindrical shell and dished heads.

2. Material of construction shall be 10 guage stainless steel ASTM

304L.

3. Design tank for 170 kPa (25 psig) working pressure. with a minimum material thickness of 10 mm (3/8 inch). Thickness of head material at any point shall not vary more than 10 percent from the nominal thickness. If the deaerator overflow is piped to the condensate tank the condensate tank shall have a design pressure and ASME stamp pressure equal to or greater than the deaerator tank’s pressure rating.

4. Tank joints shall be double-welded butt joints or single-welded butt joints with backing strips.

5. Provide 300 mm by 406 mm (12 inches by 16 inches) elliptical manway.

6. Provide nozzles for piping connections. Nozzles shall have threaded pipe connections for pipe sizes 50 mm (2 inches) and under, flanged connections for pipe sizes over 50 mm (2 inches). Flanged nozzles shall have 1035 kPa (150 psig) ASME flanges. Tank opening for pump suction pipes shall include vortex spoilers.

7. Furnish completed ASME Form U-1 or U-1A MANUFACTURERS' DATA REPORT

FOR PRESSURE VESSELS. Hydrostatically test tank at 1-1/2 times the design pressure.

8. Horizontal tank shall be supported by steel saddles, supplied by the tank manufacturer, welded to tank and anchored to the concrete bases. Design saddles to support tank (full of water), accessories, and portions of connecting piping to first hanger.

9. Affix tank nameplate to bracket that projects beyond the field-applied tank insulation. Nameplate shall include ASME stamp and data to show compliance with design, construction and inspection requirements of the Code, and tank manufacturer information.

D. Provide overflow pipe inside tank with siphon breaker.

E. Cleaning and Painting: Remove all foreign material to bare metal from interior and exterior of tank. In preparation for interior coating, sandblast interior to white metal in accordance with SSPC SP 5. Coat exterior of tank with rust-resisting primer. Refer to Section 09 91 00, PAINTING.

F. Water Level Indicators:

23 50 11 - 17

1. Gauge Glasses: Red line type, overlapping glasses if multiple glasses are utilized. Provide automatic offset-type gauge valves that stop the flow if a glass is broken. Drain cock on lower gauge valve. Gauge glass protecting rods.

2. Vertical pipe type header shall be connected to top and bottom of storage tank with tank isolation valves and valved header drain.

Viewable gauges shall cover entire diameter of tank.

3. Minimum rating 121 degrees C, 200 kPa (250 degrees F, 29 psig).

G. High and Low-Level Alarm Switches:

1. Low Level Alarm Switch: Integral unit consisting of float, float housing, hermetically sealed mercury switch. Locate external to tank on a vertical header with valved tank connections and valved drain.

Switch elevation shall be 150 mm (6 inches) above bottom of tank.

2. High Level Alarm Switch: Integral unit consisting of conductivity probes, probe housing. Float type not acceptable. Locate external to tank on a vertical header, along with the low-level switch, with valved tank connections and valved drain. High level alarm indication shall occur 100 mm (4 inches) below the overflow level.

Probes shall be ac, not dc, stainless steel with virgin Teflon insulation.

3. Provide signals to computer workstation specified in Section 23 09

4. All devices exposed to tank service conditions, including sensing devices and transmitters shall be rated for 121 degrees C, 200 kPa

(250 degrees F, 29 psig) minimum.

H. Automatic Water Level Controls:

1. Water Level Transmitter: Programmable electronics, sealed diaphragms, direct sensing electronics, no mechanical force or torque transfer devices, external span and zero adjustment.

2.3 CENTRIFUGAL MULTI-STAGE BOILER FEEDWATER PUMPS

A. Type: Two or more stages, centrifugal diffuser type, direct-coupled, vertical shaft, in-line, base-mounted, motor-driven, arranged as shown.

B. Service: Design pumps and accessories for continuous service, 115 degrees C (240 degrees F) water, with flow rates ranging from maximum scheduled on the drawings (plus manufacturer's recommended recirculation) to 10 percent of maximum (plus manufacturer's recommended recirculation). Pumps shall be suitable for parallel operation without surging or hunting.

23 50 11 - 18

C. Performance: Refer to schedules on drawings. Pump head-flow performance curve shall slope continuously upward to shut-off.

D. Control – Boiler Feed: Flow rates will be controlled by automatic modulating feedwater valves on each boiler. Pumps shall be started and stopped manually. Pumps shall have variable frequency drives controlled by boiler feed header pressure electronic control system which must be provided. Control the header pressure at 103 kPa (15 psig). For further information and requirements refer to Section 26 29 11, MOTOR

CONTROLLERS.

E. Control - Condensate Transfer: Constant speed operation. Flow rate will be controlled by automatic modulating water level control valve on condensate transfer inlet to deaerator.

F. Construction:

1. Rotating elements shall be designed and balanced to conform to sound and vibration limits specified in Section 23 05 51, NOISE AND

VIBRATION CONTROL FOR BOILER PLANT.

2. Mechanical seals shall have sealing face materials of carbon and tungsten or silicon carbide.

3. Design bearings for two-year minimum life with continuous operation at maximum pump operating load. Bearings and shaft seals shall be water-cooled if recommended by pump manufacturer for the service.

4. Materials of Construction:

a. Chambers: Stainless steel

b. Impellers: Stainless steel

c. Diffusers: Stainless steel

d. Shaft: Stainless steel

e. Suction-Discharge Chamber: Cast iron or stainless steel

G. Recirculation Orifice: Provide stainless steel recirculation orifice selected by pump manufacturer to protect pump from overheating at shut-off and designed for low noise under the service conditions. Orifices must not exceed sound level limits in Section 23 05 51, NOISE AND

H. Spare Parts: Provide complete rotating assembly for each pump size and type suitable for field installation by plant personnel. Assembly shall include impellers, diffusers, chambers, shaft, seals, and bearings.

I. Shaft Couplings: Pump manufacturer’s standard. Provide coupling guard.

J. Electric Motors: High efficiency type, open drip proof. Select motor size so that the motor is not overloaded at any point on the pump head-

23 50 11 - 19 flow performance curve. Design motor for 40 degrees C (104 degrees F) ambient temperature. For efficiency and power factor requirements refer to Section 23 05 10, COMMON WORK RESULTS FOR BOILER PLANT AND STEAM

K. Interface with Computer Workstation: Provide devices to signal computer work station that motor is on or off.

2.4 CONDENSATE TRANSFER PUMPS, CLOSE-COUPLED, END SUCTION, CENTRIFUGAL

A. Type: Single stage, end suction, centrifugal with volute casing, horizontal shaft, close-coupled with impeller mounted on motor shaft, motor driven, and constant speed, arranged as shown.

B. Service: Design pumps and accessories for continuous condensate transfer service, 93 degrees C (199 degrees F) water, with flow rates ranging from maximum scheduled on drawings (plus manufacturer's recommended recirculation) to 10 percent of maximum (plus manufacturer's recommended recirculation). Pumps shall be suitable for parallel operation without surging or hunting.

C. Performance: Refer to schedules on the drawings. Pump head-flow performance curve shall slope continuously upward to shutoff.

D. Pump Size: Shall be such that a minimum of 10 percent increase in head can be obtained at the maximum required flow rate by installing larger impellers.

E. Construction:

1. Mount pump casing on a frame attached to the motor housing. Casing shall have back pull-out feature or bolted front suction cover to allow access to impeller.

2. Frame on which pump is mounted shall provide easy access to seal.

3. Rotating elements shall be designed and balanced so that vibration is limited to requirements of Section 23 05 51, NOISE AND VIBRATION

CONTROL FOR BOILER PLANT.

4. Provide mechanical seals. Seal shall be exposed to pump suction pressure only.

5. Provide replaceable shaft sleeve, water slinger on shaft, vent cock and drain on casing. Provide casing wearing rings at all locations of tight clearances between casing and impeller.

6. Bearings: Rated for two year minimum life with continuous operation at maximum pump load.

7. Materials of Construction:

a. Casing: Cast iron

23 50 11 - 20

b. Impeller: Bronze

c. Shaft: Carbon steel

d. Shaft Sleeve: Bronze

e. Casing Wear Rings: Bronze

F. Recirculation Orifice: Provide stainless steel recirculation orifice selected by pump manufacturer to protect pump from over-heating at shutoff. Refer to Section 23 05 51, NOISE AND VIBRATION CONTROL FOR

BOILER PLANT for sound level limitations.

G. Spare Parts: Provide sufficient types and quantities to allow complete replacement of all such parts in one pump at one time:

1. Casing wearing rings

2. Shaft sleeve

3. Motor bearings

4. Mechanical seal

H. Electric Motors: Joint NEMA-Hydraulic Institute Design Type JM or JP approved motors, high efficiency, open drip proof, designed specifically as close-coupled pump motors. Motor bearings shall be grease-lubricated designed to carry all radial and thrust loads of the pump and motor assemblies. Select motor size so that the motors are not overloaded at any point on the pump head-flow performance curve. Design motors for 40 degrees C (104 degrees F) ambient temperature. For efficiency and power factor requirements, refer to Section 23 05 10, COMMON WORK RESULTS FOR BOILER PLANT AND STEAM GENERATION.

I. Sound and Vibration: Each pump and motor assembly shall conform to sound and vibration limits specified in Section 23 05 51, NOISE AND

J. Interface with Computer Workstation: Provide devices to signal computer workstation that motor is on or off.

2.5 BOILER WATER AND DEAERATOR WATER SAMPLE COOLERS

A. Type: Factory-built shell and coiled tube heat exchanger with sample in tube, cooling water in shell, designed for wall mounting.

B. Construction:

1. Shell and Head: Iron, steel or stainless-steel shell, bolted or threaded into head. Head shall have wall mounting brackets and piping connections for sample in and out and cooling water out.

Minimum design pressure for shell and head, 1035 kPa (150 psig).

Shell removable without disturbing piping connections.

23 50 11 - 21

2. Sample Coil: Shall be 6 mm (1/4 inch) outside diameter stainless steel tubing, 0.11 square meter (1.2 square feet) minimum heat exchange surface. Minimum design for 1035 kPa (150 psig), 188 degrees C (370 degrees F). Design coil to relieve stresses due to thermal expansion.

3. Arrangement: Shall be as shown on the drawings.

2.6 AUTOMATIC CONTINUOUS BOILER BLOWDOWN CONTROL SYSTEM

A. Type: One factory-assembled system per boiler to automatically sense boiler water conductivity and operate automatic electric-powered blowdown valve to maintain desired total dissolved solids content in boiler water. Micrometer-type adjustable manual blowdown valve piped to bypass the automatic blowdown valve and conductivity sensor.

B. Service: Design valves, sensors and piping for steam and water at 1035 kPa (150 psig), 186 degrees C (366 degrees F) minimum. Controller shall be suitable for 50 degrees C (120 degrees F) ambient and resist splashing water. Design automatic and manual blowdown valves for maximum blowdown flow rate equivalent to two percent of boiler steam output. System shall automatically maintain boiler water total dissolved solids at any set point between 1000 ppm and 4000 ppm.

C. Operation: Programmable timer cycles to intermittently operate the blowdown valve to obtain conductivity samples, and to maintain the valve open for a time period until the conductivity of the boiler water reaches the set point. Provide an automatic temperature compensating circuit.

D. Controller: Shall be microprocessor-based sealed unit mounted at the boiler.

1. Indicators on Panel Front: One-half inch high digital display showing conductivity and indicating normal or out-of-range conditions. Valve status indicators.

2. Membrane Keypad on Panel Front: Allows manual operation of the blowdown valve, setting of conductivity set points and alarm set points, setting of timers, calibration data input.

E. Automatic Valve Construction: Carbon steel body, Type 316 stainless steel ball and stem, TFE coated stainless steel body seal. Electric actuator with NEMA-4 or better enclosure. Rated for 1035 kPa (150 psig) minimum saturated steam.

F. Manual Valve Construction: Bronze or forged steel angle-type body, hardened stainless steel disc and seat, threaded ends, rising stem, 23 50 11 - 22 union bonnet, graduated micrometer-type dial and pointer showing amount of valve opening. Rated for 1035 kPa (150 psig) minimum saturated steam. Furnish valve blowdown chart showing flow rate versus valve opening based on 861 kPa (125 psig) boiler pressure.

G. Provide gate valves and unions at inlet of conductivity sensor and outlet of automatic control valve so that these items can be removed from the system while maintaining the manual control valve in service.

Comply with Section 23 21 11, BOILER PLANT PIPING SYSTEMS.

PART 3 - EXECUTION

3.1 INSTALLATION

A. If an installation is unsatisfactory to the COR, the Contractor shall correct the installation at no additional cost or time to the

Government.

B. Feedwater Deaerator with Storage Tank and Accessories, Condensate

Storage Tank, Blowoff Tank, Flash Tank.

1. Coordinate location with structural requirements of the building.

2. Location shall permit access to and removal of all internal and external features without removing other items of equipment or piping.

3. Bolt to building as recommended by manufacturer or as shown. Comply with seismic requirements in Section 13 05 41, SEISMIC RESTRAINT

REQUIREMENTS FOR NON-STRUCTURAL COMPONENTS. Arrange anchorage to allow thermal expansion of unit.

4. Clean interior of equipment before placing in service.

5. Deaerator vent pipes must extend vertically through roof. Horizontal runs are prohibited.

6. All controls, safeties, set points, etc. must conform to the VHA

Boiler Plant Safety Devices Testing Manual.

C. Boiler Feed and Condensate Transfer Pumps:

1. For base-mounted horizontal-shaft pumps, connect base drain to 20 mm

(3/4 inch) pipe. Extend pipe to nearest open sight or floor drain.

2. Align pumps and drivers at the factory. At job site, a millwright shall level, shim, bolt, and grout the base plates or base frames onto the concrete pads, and shall also check the alignments of flexible-coupled pumps and drivers and make corrections necessary.

Check alignment when both pump and driver are at normal operating temperature.

23 50 11 - 23

3. Where packaged deaerator-feed pump unit is required, boiler feed pump base plates shall be welded or bolted to deaerator support frame.

4. If water-cooled bearings or quenched or flushed or water-cooled stuffing boxes are provided on pumps, contractor shall install on each pump valved 15 mm (1/2 inch) piping connections to cold water supply, and 15 mm (1/2 inch) drains to nearest open sight drain.

Provide unions at all connections to pumps.

D. Automatic Continuous Boiler Blowdown Control System: Locate controller on floor-supported angle at four feet above the floor at the boiler adjacent to the continuous blowdown valves. Keypad and indicator must face aisle.

3.2 TESTING AND BALANCING FEEDWATER DEAERATOR WITH STORAGE TANK AND

ACCESSORIES

A. Demonstrate the ability of the deaerator to perform as specified in regard to oxygen removal and outlet temperature, over the required output flow range and input temperature range of unit. Test performance at 5 percent and 100 percent of capacity, and at two intermediate points to be selected by the COR. Repeat test two times at each load point.

B. Determine temperatures and pressures by calibrated thermometers and pressure gauges.

C. Utilize the specified colorimetric comparator type dissolved oxygen test kit. After completion of tests, clean the test kit apparatus, replace all ampoules used and parts missing or broken, and deliver the kit to the COR.

D. Various impurities in feed water can interfere with the colorimetric test. When impurities are present, the Contractor shall be prepared to test for dissolved oxygen using the titration test as described in ASME

PTC 12.3. COR may permit other test methods.

E. This test shall be performed in conjunction with any boiler tests that are specified.

F. Prior to requesting final tests, pretest unit using method specified for final test. All final tests must include at the minimum the tests listed in the VHA Boiler Plant Safety Devices Testing Manual. Submit test data for review.

G. All permanent work platforms shall be in place before testing. The use of or need for step ladders to perform any inspection, test, or

23 50 11 - 24 maintenance shall be considered a failure to install the equipment in accordance with specifications that require access to equipment. The contractor shall correct at no additional cost or time to the

Government before beneficial use can start.

3.3 STARTUP AND TESTING

A. Perform tests as recommended by product manufacturer and listed standards and under actual or simulated operating conditions and prove full compliance with design and specified requirements. Tests of the various items of equipment shall be performed simultaneously with the system of which each item is an integral part.

B. When any defects are detected, correct defects and repeat test at no additional cost or time to the Government.

C. The Commissioning Agent will observe startup and contractor testing of selected equipment. Coordinate the startup and contractor testing schedules with the COR and Commissioning Agent. Provide a minimum notice of 10 working days prior to startup and testing.

3.4 COMMISSIONING

A. Provide commissioning documentation in accordance with the requirements of Section 23 08 00, COMMISSIONING OF HVAC SYSTEMS.

B. Components provided under this section of the specification will be tested as part of a larger system.

3.5 DEMONSTRATION AND TRAINING

A. Provide services of manufacturer’s technical representative for 4 hours to instruct each VA personnel responsible in operation and maintenance of the system.

B. Submit training plans and instructor qualifications in accordance with

C. Comply with Section 23 08 11, DEMONSTRATIONS AND TESTS FOR BOILER

PLANT.

- - - E N D - - -

08-01-17

23 52 39 - 1

DEISECTION 23 52 39

FIRE TUBE BOILERS

PART 1 - GENERAL

1.1 DESCRIPTION

A. This section specifies packaged fire tube boiler with trim

(accessories), dual fuel (natural gas and No. 2 oil) burner, fuel valve and piping trains, and other accessories.

B. A complete listing of common acronyms and abbreviations are included in

1.2 RELATED WORK

A. Section 01 00 00, GENERAL REQUIREMENTS.

B. Section 01 33 23, SHOP DRAWINGS, PRODUCT DATA, AND SAMPLES.

C. Section 01 81 13, SUSTAINABLE CONSTRUCTION REQUIREMENTS.

D. Section 01 91 00, GENERAL COMMISSIONING REQUIREMENTS.

E. Section 13 05 41, SEISMIC RESTRAINT REQUIREMENTS FOR NON-STRUCTURAL

COMPONENTS.

F. Section 23 05 10, COMMON WORK RESULTS FOR BOILER PLANT AND STEAM

G. Section 23 05 51, NOISE AND VIBRATION CONTROL FOR BOILER PLANT.

H. Section 23 08 00, COMMISSIONING OF HVAC SYSTEMS.

I. Section 23 08 11, DEMONSTRATIONS AND TESTS FOR BOILER…