36C25518R0547-013.pdf

08-01-17

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SECTION 23 09 11

INSTRUMENTATION AND CONTROL FOR BOILER PLANT

PART 1 - GENERAL

1.1 DESCRIPTION

A. Automatic controls, instruments, monitoring and data management systems and accessories for the boilers, burners and other boiler plant mechanical equipment. The specification classifies the systems into automatic boiler and burner control systems, burner management systems

(flame safeguard), and data management and instrumentation systems.

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 13 05 41, SEISMIC RESTRAINT REQUIREMENTS FOR NON-STRUCTUAL

COMPONENTS.

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

GENERATION.

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 PLANT.

J. Section 23 10 00, FACILITY FUEL SYSTEMS.

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

L. Section 23 50 11, BOILER PLANT MECHANICAL EQUIPMENT.

M. Section 23 51 00, BREECHINGS, CHIMNEYS, AND STACKS.

N. Section 23 52 39, FIRE-TUBE BOILERS.

O. Section 26 05 11, REQUIREMENTS for ELECTRICAL INSTALLATIONS.

P. Section 26 05 19, LOW-VOLTAGE ELECTRICAL POWER CONDUCTORS AND CABLES.

Q. Section 26 05 33, RACEWAY AND BOXES FOR ELECTRICAL SYSTEMS.

R. 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

23 09 11 - 2 basic designation only. Where conflicts occur these specifications and the VHA standard will govern.

B. American National Standards Institute (ANSI):

INCITS 154-1988(S2009)..Office Machines and Supplies - Alphanumeric

Machines - Keyboard Arrangement

C. American Society of Mechanical Engineers (ASME):

B31.1-2014..............Power Piping

B40.100-2013............Pressure Gauges and Gauge Attachments

PTC 4-2013..............Fired Steam Generators

D. National Electrical Manufacturers Association (NEMA):

ICS 6-1993(R2001, R2006) Industrial Control and Systems:

Enclosures

WC 63.2-1996(R2003).....Performance Standard for Coaxial Premise Data

Communications Cables

E. National Fire Protection Association (NFPA):

70-2014.................National Electrical Code

85-2015.................Boiler and Combustion Systems Hazards Code

F. Underwriters Laboratories Inc. (UL):

508-1999(R2013).........Standard for Industrial Control Equipment

1449-2014(R2016)........Standard for Surge Protective Devices

1998-2013...............Standard for Software in Programmable

Components

G. Department of Veterans Affairs (VA)

........................VHA Boiler Plant Safety Devices Testing Manual, Fourth Edition

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 09 11, INSTRUMENTATION AND CONTROL FOR

BOILER PLANT”, 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.

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D. Certificates of compliance with paragraph, QUALITY ASSURANCE of this section (subparagraphs 1.5.A, B, D & F). In addition, submit Past

Performance Questionnaire (form attached) for five (5) past projects of the same class (scope & complexity) as this project.

E. Submit information sufficient to verify compliance with all contract requirements as specified and shown on project drawings.

F. Automatic Boiler Control and Burner Management and Safety Interlock

Systems:

1. Catalog cuts and specification sheets providing description and performance data on: Controllers, control and indicating stations, sensors and transmitters, signal conditioners, electric switches and relays, indicators and annunciators, safety interlock devices, drive units and actuators, control valves, mechanical linkage systems, compressed air filters and regulators.

2. Statement from controller manufacturer that the type and model submitted is the current generation and that the manufacturer will support the units with parts and service for at least ten years, and that the equipment submitted meets all VA specifications.

3. Information on all the specific systems that is sufficient to allow complete troubleshooting. As a minimum, this should include explanation of the control logic, and wiring diagrams of equipment and systems to include locations and wire numbers of all safety device test points that will be required to complete safety device testing in accordance with VA requirements, and sequence of operation of all components of the system.

4. Hardware systems schematics showing field and panel equipment interface block diagram.

5. Location of interlock devices on the burners, boilers, fuel trains and accessory equipment, all safety devices shall be easily accessible for testing...

G. Boiler Plant Instrumentation:

1. Catalog cuts and specification sheets providing description and performance data on instruments and accessories.

2. Installation and troubleshooting instructions for all equipment in bound sets shipped with equipment.

3. List of ranges of recorder displays. Paper chart recorders are prohibited.

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4. Flow meter primary element design, size, performance, and sizing calculation. Steam flow performance data for flow meters verifying project performance requirements.

5. Complete wiring and piping diagrams for all equipment and systems.

6. Wiring and piping materials.

H. Instrumentation and Control Panels:

1. Drawing showing arrangement of instruments and controls on panels.

2. Drawing showing panel arrangements, construction, door swing clearance allowance, dimensions, finishes.

3. Description of panel construction.

4. Seismic restraint design data for freestanding instrument or control panels. Refer to Section 13 05 41, SEISMIC RESTRAINT REQUIREMENTS

FOR NON-STRUCTURAL COMPONENTS.

I. Computer Workstation and Programming:

1. Catalog data with pictures, description, and performance data on all hardware.

2. Hardware specifications.

3. Software model number and supplier. Include complete documentation on all software with shipment.

4. Confirmation that graphics to be provided complies with the specification.

5. Description of computer furniture.

J. As-built Logic and Wiring Diagrams: One set of reproducible prints and

CAD disks delivered to COR prior to turning systems over to VA for operation. Supply revised drawings if changes are made during the startup and commissioning process.

K. Fluid Flow Meters:

1. Catalog cuts and drawings with description, specifications and dimensions of meters and accessories.

2. Design and construction of meters and accessories.

3. Performance data including flow, pressure drop, accuracy over the metering range of the actual fluids to be metered.

4. Pressure and temperature limitations.

5. Manufacturer's installation instructions.

6. Arrangement of register face and remote indicator (if provided).

L. Pressure Gauges and Thermometers:

1. Catalog cuts showing design, construction, dimensions of gauges and accessories.

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2. Accuracy.

3. Pressure and temperature limitations of gauges and accessories.

4. List of scale ranges to be provided.

M. 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.

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

N. 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.

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

1.5 QUALITY ASSURANCE

A. The boiler and burner control, monitoring, data gathering, instrumentation and associated systems specified in this section shall be provided by one company that has been in business at least three years engineering, designing and servicing industrial and institutional boiler control and instrumentation systems similar to those specified herein, as a primary business. That company shall furnish all components and provide complete calibration, programming, start-up, testing, demonstrations, instructions and training services.

B. Submit documented evidence, including start-up and acceptance test data, and references, that the company has performed satisfactory work on at least six systems similar to those specified, list any VA boiler plant projects completed in the past. For instance, submit experience information on systems involving parallel positioning combustion control and on variable speed forced draft fan drives, if these systems are specified. Submit in writing that all specifications were read and fully understood.

C. If new burners are part of the contract, the burner manufacturer shall be responsible for the burner management system (flame safeguard), including interlocks, all accessories and for coordination with other control and monitoring systems.

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D. Equipment Experience Requirements: Refer to Section 23 05 10, COMMON

WORK RESULTS FOR BOILER PLANT ANDSTEAM GENERATION.

E. Code Approval:

1. All burner management and combustion control systems and devices shall comply with NFPA 85, regardless of boiler type or size.

Locations and arrangements of safety devices on fuel trains shall comply with diagrams included in “Annex A” in the code, as modified by the VA standard details and the VHA Boiler Plant Safety Devices

Testing Manual requirements.

2. All burner management controls and interlock devices shall be UL listed and FM approved. All controllers that include burner management functions shall be UL listed and FM approved.

3. Parallel positioning combustion control systems shall comply with UL

1998.

4. Computer-based electronic equipment shall conform to the requirements of FCC Part 15, Subpart J, for Class A computing devices governing radio frequency electromagnetic interference (EMI) while continuing to operate normally.

5. All electrical wiring shall be in accordance with NFPA 70.

6. The use of wire nuts is prohibited. All wire connections must be made at terminal blocks and terminal strips.

7. The use of liquid tight or other flexible conduit systems is limited to 900 mm (3 foot) in length unless longer runs are required for door swings or other equipment access.

8. All wire runs are required to be in conduit.

F. Personnel: All work shall be done by properly trained, skilled technicians who are regularly employed and qualified in the installation, programming, start-up, calibration, and testing of the systems provided, and who will be directed by experienced engineers employed by the equipment supplier. Personnel must have three years minimum experience with industrial and institutional boiler plant controls and instruments similar to those being furnished for this project.

1.6 AS-BUILT DOCUMENTATION

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

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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 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. As-built drawings are to be provided, with a copy of them on AutoCAD version 17 provided on CD or DVD. The CAD drawings shall use multiple line layers with a separate individual layer for each system.

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.

Coordinate lockout/tagout procedures and practices with local VA requirements.

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

23 09 11 - 8 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

2.1 AUTOMATIC BOILER/BURNER CONTROL SYSTEM, NOT INCLUDING BURNER MANAGEMENT

(FLAME SAFEGUARD)

A. Testing

1. All Boiler and control testing shall be completed in accordance with the VHA Boiler and Associated Plant Safety Device Testing Manual, Fourth Edition, October 2017

B. Basic Description of Controllers and Control Functions:

1. Controllers shall be industrial-process-grade multi-loop programmable microprocessor or programmable logic controllers (PLC).

2. Controllers shall be manufactured separate from and shall be separate assemblies, in a separate electrical cabinet from the

Burner Management (Flame Safeguard System).

3. Control functions:

a. Control of burner firing rates to maintain steam header pressure.

b. Parallel-positioning combustion control (air/fuel ratio, excess air) with flue gas oxygen trim.

c. Boiler water level, 1 element system.

4. Control features:

a. Operator interface on controller faceplates and touch screens and computer workstation. Operator interface shall include manual/automatic selection, manual loading, and displays that show set point, process variable, and signal to actuator, process status and controller status. Touch screens have additional display requirements; refer to the following paragraph.

b. Provide separate dedicated controllers/panels for each boiler and for the master steam pressure control. Fuel/air control loops, including FGR and oxygen trim may be incorporated into one station for each boiler. Boiler/economizer outlet draft and boiler water level control shall have separate stations for each item on each boiler. All control items for one boiler may be shown on one touchscreen for that boiler. Each boiler shall have its own touch screen located in the panel for that boiler.

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c. VA Boiler Plants PROHIBIT any boiler to be automatically or remotely started and lead lag control systems are prohibited within the VA boiler plants, regardless of the size or type of boiler. The boiler shall be started by an operator standing at the boiler.

d. Variable frequency drives on forced draft fan motors.

5. Refer to paragraph, BURNER MANAGEMENT (FLAME SAFEGUARD CONTROL)

SYSTEM WITH SAFETY INTERLOCKS AND ACCESSORIES for burner management controls.

C. Controllers: Multiple-loop programmable microprocessor or programmable logic (PLC) proportional-integral-differential (PID) solid state electronic controllers shall control all functions except burner management.

1. Accuracy: 0.1 percent analog inputs and outputs.

2. Resolution: 16-bit input and output.

3. Environment: 0 to 50 degrees C (32 to 122 degrees F), 15 percent to

95 percent RH, non-condensing.

4. As a minimum, each controller shall have capability for four analog and four digital inputs, two analog and four digital outputs, and two PID loops.

5. Memory retention for power failure or for storage as spare parts.

6. Displays shall be a combination of English language, color graphics, and digital with 0.5 percent resolution, visible from wide angle.

7. Bumpless manual/automatic transfer.

8. High and low alarms for all inputs.

9. Programming: Controllers shall have capability for quick (5 to 10 minutes) reloading of memory by operating personnel upon memory loss. Provide all software and hardware necessary to allow field downloading of configuration memory to the microprocessors.

10. Password Protection: Provide levels of password protection for all safety related options and parameters including all commissioning programming. Provide all passwords to COR.

11. In the event of a controller fault, the controller shall have a dedicated relay output that results in the shutdown of the boiler and provides an alarm to a panel-mounted light and audible alarm.

Failure of control system for one boiler shall not affect automatic and manual operation of other boilers.

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12. Controllers and software that operate variable frequency drives shall be manufactured and tested in accordance with UL 508.

13. Controllers shall provide serial RS232/RS485 Modbus communication with computer workstation running latest Microsoft Windows based operating system. This includes data gathering and processing, report generation, monitoring, annunciation and control. Refer to paragraph, COMPUTER WORK STATION AND PROGRAMMING. It shall be possible to defeat the remote control from the front panel of each individual controller, preventing any status changes from being initiated at the computer workstation.

14. All controllers, including those assigned to data processing, shall be same model and series.

15. Controllers shall be the current generation product that will be supported by the manufacturer, with parts and service, for a minimum of ten years from time of installation.

16. All controllers shall be mounted within specified control panels.

17. Examples of acceptable controllers: Prefered “PCC-IV”, Hays-

Cleveland “AC Station”; MicroMod “Mod 30 ML”; Toshiba “LC500”; and

Fireye Nexus “PPC 4000”. All controllers with integrated flame safeguard are prohibited.

D. Power Supplies: Provide separate uninterrupted power supply for each boiler controller. Any signal that is common to all boilers, such as plant master control signals, shall be isolated from all other boilers so that failure in one boiler circuit will not affect other boilers.

E. Touch Screen Operator Terminals:

1. Provide one touch screen control station and display for each boiler mounted on the boiler control panel. Touch screen shall be in complete communication with all controllers associated with the boiler and with the burner management system. Provide alternate control station to replace touch screen control functions if touch screen fails.

2. Control Station and Display Requirements:

a. Local operation and programming of controllers, graphic display of information, alarm message display, historical and real-time trending, remote controller tuning, x/y plots of fuel air curve data for intuitive commissioning of controllers, Ethernet connectivity and standard Internet browser remote communication.

Network to boiler control and burner management systems.

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b. Selection of automatic or manual control of firing rate. Local manual control to increase and decrease the firing rate.

c. Indicate burner management control status and diagnostics in

English messages: control on, pre-purge, trial for ignition, igniter flame signal, main flame signal, post purge, burner off, all diagnostic information available from burner management system, continuous indication of flame signal.

d. Real time display of all connected process parameters including control output, set point, process variable, all data gathering and processing from all controllers associated with the boiler.

e. Display of all control system alarm messages and faults. History of alarms and faults and recommendations for troubleshooting.

f. Complete display and facilities to allow programming all controllers associated with the boiler or the master control.

Burner management is excluded from this requirement.

g. Provide alternate means of automatic and manual operation of boiler firing rates and burner management status if touch-screen fails.

h. Provide continuous display of critical operating parameters, including but not limited to the following:

1) Steam Pressure

2) Water Level

3) Draft Pressure

4) Firing Rate

3. Touch Screen System Hardware and Software:

a. 265 mm (10.4 inch) panel-mounted display, TFT with 256 colors, 640 x 480 pixel LCD resolution. Locate to allow easy viewing and access from operating floor.

b. Aluminum case allowing entire enclosure to be rated NEMA 4X.

c. Communication with Supervisory Control and Data Acquisition

(SCADA) program on computer work station.

d. Multiple RS485 Modbus communication interfaces.

e. Field-replaceable backlight, real-time clock, battery-backed clock time stamps critical data, 8 MB on-board flash application memory, 512 MB memory-card, application expanded memory-card for historical, alarm and event storage, resistive analog touch screen with free formable to fit target shape.

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f. Operation interaction shall be touch-based allowing easy selection of screens, manual/automatic status changes, start/stop functions, set point changes, output changes and PID tuning parameters without any special programming skills. Screen selection shall also be available through tactile feedback function keys.

g. Show facsimiles of each controller and clearly labeled English language and engineering unit display of the control parameters.

h. Graphic X/Y curve data plotting capability. When used in conjunction with fuel/air ratio control, provide automated fuel/air ratio curve and oxygen trim set point curve adjustment for rapid, error free burner tune-up. Only a single operator action shall be required to store commissioning data into multiple characterizer curves for a particular load point.

i. Configuration software Microsoft Windows based. Provide all necessary software to allow field modification or expansion of the system including graphics drawing programs and data base builders. Systems based on “run time only” programs are not acceptable.

F. Drive Units and Actuators for Dampers, Fuel Flow Control Valves, Feedwater Flow Control Valves:

1. Electric drive units are required.

2. Electric drive units shall have continuous modulating duty cycle without any duty cycle or thermal motor limitations. Shall start instantaneously at full rated torque, stop instantaneously without coast or overshoot. Shall smoothly operate all connected devices without overload. Provide 100 percent duty cycle maintenance free motors that never overheat or burnout under stalled conditions.

Gearing shall eliminate backlash. Movement shall be constant speed and shall be coordinated with the controlled process so that performance parameters remain within specified limits.

3. Additional Requirements for Electric Drive Units on Parallel-

Positioning Combustion Control Systems:

a. Drive units shall have precise positioning and repeatability to provide air-fuel positioning ratios with a maximum hysteresis of

2 percent.

b. Provide continuous precise feedback signals from drive units to controllers.

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c. Provide auxiliary contacts to prove low and high fire positions.

Feedback signals are prohibited to perform this function within the VA. Belt-type drive units are prohibited.

d. Drive unit shafts shall be keyed to fuel flow control valves and damper shafts to eliminate the possibility of slipping.

e. Drive units shall be industrial rated.

f. All gearing shall be brass or better. Plastic gears of any kind are prohibited.

4. Boiler outlet damper drive units may be different model than drive units for fuel valves. Drive units shall be capable of 136 Nm (100 ft-lb.) torque minimum. Less powerful drive units may be utilized if certified as adequate by the burner manufacturer.

G. Variable Frequency Drives (VFD) for Forced Draft Fans:

1. Refer to Section 26 29 11, MOTOR CONTROLLERS, for electrical requirements. In addition, there shall be a VFD mounted operator interface unit that allows configuration of drive parameters and displays diagnostic information for troubleshooting. The minimum speed is limited to 40 Hz.

2. Provide feedback system including motor speed and direction of rotation to combustion controller. Feedback transmitter must have no-drift guarantee. Feedback system shall not be affected by position of HOA switch on motor control system.

3. Provide noise filters.

4. The VFD shall automatically limit the rate of fan speed increase to that which will prevent an over-current trip in the event of a

“step” speed increase of 0 to 100 percent.

5. Provide constant speed feature and operator-selectable air/fuel program in the controller for constant speed operation maintaining specified air/fuel ratios at all firing rates or positions (excess air).

6. Forced draft fan damper operation is required in conjunction with operation of the VFD at the lower firing rates.

7. Provide a means of proving fan RPM to control set point at any firing rate. Deviation from set point RPM or greater than 2 percent will cause a safety shutdown of the boiler. As an option the contractor may install a fully metered system where air flow is proven at all firing rates and a shutdown will occur if the airflow varies by more than 2 percent.

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H. Transmitters: See paragraphs, PRESSURE SENSORS AND TRANSMITTERS and

TEMPERATURE SENSORS AND TRANSMITTERS.

I. Final Control Elements:

1. Fuel flow control valves, forced draft fan dampers, FGR dampers (if provided), variable frequency forced draft fan drives (VFD) (if provided), feedwater control valves: Refer to Section 23 52 39, FIRE-TUBE BOILERS.

2. Dampers in stacks and breechings: Refer to Section 23 51 00, BREECHINGS, CHIMNEYS, AND STACKS.

J. Uninterrupted Power Supplies:

1. Provide separate complete protected power conditioners for each boiler control and for master control. Power supply shall protect all computers, controls, instruments and accessories from damage due to ground leakage, spikes, sags, surges, transients and overloads in the incoming power supply.

2. Line interactive, UL 1449 rated, interactive digital display.

Automatic internal bypass. Smooth sine wave output.

3. Suitable for ambient temperature of 43 degrees C (110 degrees F) in boiler room panel.

4. Hot swappable batteries.

5. Audible and visual alarms to signal failure of power supply.

K. Spare Parts and Tools:

1. Master control steam pressure transmitter: One complete unit, calibrated for the service.

2. Hardware and software sufficient for downloading and uploading all programming configurations with all the controllers.

3. Electric power drive unit: One of each size and type used

L. Detailed Control Functions:

1. Control of Burner Firing Rates to Maintain Steam Header Pressure:

a. Automatic modulation of burner firing rates on all boilers to maintain set pressure of main steam-header. Master controller receives signal from header pressure transmitter, processes and transmits signal to submaster controller for each boiler/burner.

Submaster controls fuel flow and combustion air flow.

b. Set Points and Performance: Accuracy plus or minus two percent of the set pressure when steam load changes do not exceed 20 percent of the maximum continuous rating of the largest boiler in service in a 60 second period. System oscillations shall be minimal.

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c. Control Stations: Individual control stations for master and submaster controllers. Locate control stations on main instrumentation panel unless otherwise shown. Master controller shall have capability for two set points with easy selection.

d. Low fire hold capability and user definable optimum ignition position.

e. Interface with burner management system for automatic positioning forced draft fan speed and fuel flow control valves during pre-purge, ignition, shutdown and post-purge.

f. Interlocks to prove proper positions of forced draft , forced draft fan speed, and fuel flow control valves for ignition and running cycles. Refer to paragraph, BURNER MANAGEMENT (FLAME

SAFEGUARD CONTROL) SYSTEM WITH SAFETY INTERLOCKS AND ACCESSORIES.

g. The steam header pressure transmitter(s) shall be dedicated to header pressure control. Suppressed range transmitter(s), each with range +/- 20 percent of required set point. If two set points are required that are more than 138 kPa (20 psig) apart, provide two transmitters. Locate transmitters adjacent to main steam-header. Refer to Paragraph, PRESSURE SENSORS AND

TRANSMITTERS.

2. Parallel-Positioning Combustion Control (Air/Fuel Ratio, Excess

Air):

a. Boiler/burner submaster controller provides firing rate signals to separate drive units (actuators) for forced draft fan dampers and for each of the fuel flow control valves and to the variable frequency drive (VFD) of the forced draft fan. Air/fuel ratio maintained by firmware and software programming of the submaster controller. Software shall be factory-programmed by the controller manufacturer only, for the specific application. Only tuning and scaling shall be performed in the field. Any and all other field adjustments are prohibited.

b. Hardware, firmware and software shall comply with UL 1998.

Incorporate cross-limiting (air leading fuel on load increases, fuel leading air on load decreases) and deviation limiting

(allowable tolerances on air/fuel ratio). Provide automatic burner shutdown if deviation exceeds programmed limits or if there is a controller failure. Cross-limiting and deviation limiting shall be tested and proven. If at any time it is found

23 09 11 - 16 this was not preprogrammed at the factory and UL tested and listed the controller shall be replaced at no additional cost or time to the Government. Only tuning and scaling shall be performed in the field. Any and all other field adjustments are prohibited.

c. Provide feedback signals from drives and actuators.

d. Accuracy of control of drive units shall result in fuel-air positioning ratios that are specified by the burner manufacturer for efficient and safe operation with a maximum hysteresis of 2 percent. Excess air in flue gas shall conform to limits given below.

e. Manual control function accessible to operating personnel shall be confined to base loading the firing rate of the burner and shall prohibit separate control of fuel or combustion air. All other manual functions shall be password protected intended to be accessible only to qualified technicians. If system is improperly placed in a manual control mode, the system shall shutdown the boiler or maintain safe excess air levels at all times, within parameters that limit the carbon monoxide emissions to specified limits.

f. From low fire to high fire the air/fuel ratio (excess air) shall be programmed over at least ten evenly spaced increments of fuel input.

g. Control positions and display indications shall be linear in relation to firing rate. For example, 20 percent control position shall be 20 percent firing rate (20 percent of full load).

h. Mechanical connections between drive units and dampers and valves shall not have hysteresis and shall be keyed to eliminate slippage. Use of linkage systems must be minimized and submitted for approval as a deviation to the contract.

i. Excess Air and Emissions Limits – New Burners: Refer to the boiler and burner specification.

3. Automatic Flue Gas Oxygen Trim System:

a. Boiler/burner submaster air/fuel controller shall utilize signal from flue gas oxygen analyzer and vary the combustion air flow to maintain the specified air/fuel ratio (excess air) at all firing rates 20 percent of maximum firing rate and greater.

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b. Operation and Performance:

1) Separate characterized set point curves for each fuel, minimum ten points per fuel. A single curve with biasing for the other fuel is not acceptable. Automatic changeover of set point curves when type of fuel being fired is changed.

2) Maximum deviations from set points shall not exceed ten percent at any firing rate. Combustion shall not generate carbon monoxide (CO) in excess of 200 ppm at any time.

3) At firing rates below 20 percent of maximum steam flow, trim shall automatically return to null position (no trim).

4) Variable gain to decrease output sensitivity at low loads.

5) Adjustable high and low trim limiting. Excessive high or low trim correction, low excess air, or oxygen analyzer failure shall actuate audible and visual alarm on the boiler submaster air/fuel ratio controller. Analyzer failure shall cause system to go to null position.

6) Manual trim output shall revert to null setting when system is placed in automatic control.

c. During burner start-up and adjustment of air/fuel ratios (excess air) by service technician, trim shall be on manual control at null position.

d. Refer to paragraph, FLUE GAS OXYGEN ANALYZERS.

4. Boiler Water Level Control:

a. Automatically modulate the position of feedwater control valve on each boiler to maintain the water level in the boiler within plus or minus 50 mm (2 inches) of set point with instantaneous load swings of 20 percent of boiler capacity. Adjustable set point.

b. Type of System:

1) Single Element System: Utilize signal from water level sensor on boiler.

c. Boiler Water Level Sensors:

1) Differential Pressure Transmitters: Provide on water tube boilers. Refer to paragraph, PRESSURE SENSORS AND

TRANSMITTERS.

2) Water Level Sensing and Safety Control Systems: Provide on fire tube boilers. Refer to Section 23 52 39, FIRE-TUBE

BOILERS.

d. Steam Flow Sensors: Refer to paragraph, FLOW METERS.

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e. Feedwater Pressure Sensors: Refer to paragraph, PRESSURE SENSORS

AND TRANSMITTERS.

f. Controller: Controllers for water level control shall include:

manual/auto control station and indicators showing signal level to actuator, set point and actual water level. Locate on main instrumentation panel unless otherwise shown. For controller requirements for fire tube boilers, refer to Section 23 52 39, FIRE-TUBE BOILERS.

g. Set point position as recommended by boiler manufacturer.

5. Boiler and Economizer Efficiency Calculation and Display: If not provided on the computer work station, provide continuous automatic calculations and indication of heat-loss combustion efficiency based on flue gas outlet temperature of economizer (or boiler if economizer is not provided), flue gas oxygen, and type of fuel in use. Base calculation method on ASME Performance Test Code, HEAT

LOSS EFFICIENCY form, with no consideration for boiler radiation and unaccounted losses.

2.2 BURNER MANAGENENT (FLAME SAFEGUARD CONTROL) SYSTEM WITH SAFETY INTERLOCKS

AND ACCESSORIES

A. Complete automatic safety control and monitoring system for burner ignition sequencing, operating cycle, and shut-down sequencing. System shall include microprocessor programmer, self-checking ultraviolet (UV) flame scanner and amplifier, burner cycle display, first-out diagnostic annunciation display, burner safety shutdown interlocks, communication with monitoring systems, and accessories. Mount controllers, control switches and displays in and on individual boiler control panels. Refer to paragraph, BOILER/BURNER CONTROL PANELS. All interlock devices shall be designed to permit periodic operational testing, including set points and trip points, without changing set points or programming, and in accordance with the VHA Boiler Plant Safety Devices Testing Manual.

1. Controller shall be manufactured separately from the Burner Control

System controller.

2. Controller shall be a separate and individual assembly from any other controller.

3. Controller shall have its own mounting and wiring base to permit the controller to be replaced without disturbing any wiring or other components.

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B. Code Compliance: Conform to NFPA 85. All components UL listed, FM approved.

C. Operate on 102 to 132 volts; 60 Hertz ac. Operating ambient temperature range 0 to 52 degrees C (32 to 125 degrees F).

D. Flame Scanners: Provide self-checking ultraviolet (UV) scanners. Self-checking UV scanners shall have minimum checking frequency six times per minute. Position scanners so that they do not view the ignition spark. Scanner sight tubes must be non-reflective to avoid the scanner detecting the reflection of the ignition spark. UV non-self-checking scanners are prohibited because they can fail in an unsafe mode on continuously operated burners.

E. Control Features:

1. Automatic recycling on high steam pressure only.

2. Interrupted ignition.

3. Electronically prevent UV scanner sensing ignition spark. Methods include early spark termination or by phasing the firing of the ignition spark off cycle from the scanner activation.

4. Flame failure response time four seconds maximum.

5. Ten seconds trial for ignition except 15 seconds permitted on heavy oil fuel.

6. Pre-purge timing set for 4 air changes on fire tube boilers and 8 air changes on water tube boilers per NFPA 85. The exact timing must be determined by the boiler manufacturer. For example, typical pre-purge timing with wide open forced draft damper and forced draft fan at full speed has been 30 seconds for packaged fire tube boilers and

2 minutes for packaged water tube boilers. Once purge time has been determined and set it becomes burnt into the program and may not be changed.

F. Provide components that can be easily removed from the panel without disturbing wiring.

G. Memory storage and self-diagnostics of at least six most recent causes of burner shutdown, which can be accessed by operating and service personnel. Diagnostics shall include all individual interlocks.

H. Provide Modbus RS232/RS485 and modem interface to allow remote access to detailed boiler plant operating data and memory. Provide interface with SCADA software on computer workstation to allow access to burner management memory and to current operating information. In addition, 23 09 11 - 20 provide a BACnet (read only) interface to the central VAMC DDC control system.

I. Burner cycle indication on face of panel: Separate display from the touch screen. Show instantaneous status of startup, run and shutdown program. Provide indicator for control power on, ignition, main fuel valve open, and flame failure.

J. Reset button on face of panel. Separate display from the touch screen.

K. Annunciator Display and Alarm:

1. Separate display from the touch screen.

2. Locate display on outside face of panel between 1200 mm and 1500 mm

(4 feet and 5 feet) above the floor.

3. English language read-out with individual identification of specific interlocks. Where two or more interlocks serve the same function, individual display of each interlock is not required.

4. Indicate burner status in English messages: control on, pre-purge, trial for ignition, igniter flame signal, main flame signal, post purge, burner off.

5. Continuously indicate flame signal strength.

6. Provide first-out annunciation, including English language message, and audible alarm (horn) for each of the following interlocks:

a. Flame failure.

b. Purge airflow low.

c. Combustion air low.

d. False combustion air (switch activated with combustion air flow).

e. High main gas fuel pressure.

f. Low main gas fuel pressure.

g. High oil pressure.

h. Low oil pressure.

i. Low igniter (pilot) gas pressure.

j. Low oil temperature (heated oil systems only).

k. Fuel safety shut-off valves not closed prior to ignition cycle.

l. Low fire position not attained prior to ignition cycle.

m. Low atomizing media (steam or air) static pressure at atomizing media service connection to burner piping.

n. Low atomizing steam/oil differential pressure. Where burner does not maintain differential pressure provide low atomizing media pressure at burner.

o. High steam pressure.

23 09 11 - 21

p. Low water cutoff.

q. FGR (if provided) improper damper position.

r. Low flue gas oxygen.

s. High furnace pressure.

t. Building combustion air intake louver closed or make-up air ventilation system not operating.

7. Audible alarm (horn): Sounds upon all burner shutdowns except automatic recycle shutdowns on steam pressure. Provide silencing control, which automatically resets when burner control is reset.

L. Pre-Purge Timing: Integral with the programmer. Non-adjustable after initially set to suit boiler pre-purge requirements.

M. Auxiliary relays: Industrial type rated for the service, enclosed contacts.

N. Selector switches, push buttons and control switches: Heavy duty, industrial type.

O. Safety shutdown and manual reset required for, but not limited to:

1. Flame signal detected prior to ignition cycle.

2. Pre-ignition interlock open during pre-purge.

3. High fire purge interlock fails to close within ten minutes or less after firing rate drive unit is commanded to drive to high fire.

4. Low fire interlock fails to close within ten minutes or less after firing rate drive unit is commanded to drive to low fire.

5. Igniter (pilot) or main burner fails to ignite.

6. Malfunction of flame detector.

7. Malfunction of programmer.

8. Malfunction of flame signal amplifier.

9. Combustion air proving switch actuated prior to start-up of forced draft fan.

10. Lock-out interlock open during pre-purge (after 15 seconds), ignition or run period.

11. Interlock open.

12. Flame failure.

13. Building combustion air intake louvers closed or make up air ventilation system not operating.

P. Burner Safety Shutdown Interlock Devices:

1. Basic Requirements:

a. Adjustable Set Points.

b. Maximum Set Point Deviation: 5 percent of full scale.

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c. Minimum Repeatability: 2 percent of full scale.

d. Minimum Set Point Accuracy: 10 percent of full scale or 20 percent of set point.

e. Scale range shall allow set points to be within 30 to 70 percent of full scale.

f. Safety interlock devices shall be separate from operating control elements, such as feedback devices. This is to avoid having the failure of an operating control device preventing the operation of the safety device. All safety devices shall be hardwired directly to the flame safeguard controller without passing thru any other device or control system.

2. Provisions for Testing of Interlocks:

a. Installation of all interlock devices shall permit testing of set points and control operation without removing or disconnecting the devices and without adjusting set points of devices. Provide permanent connection points for test instruments, such as manometers and pressure gauges, on sensing piping and tubing.

Where necessary, provide lockable valves to allow temporary isolation of device from the service to allow testing of the device. All test points shall be easily accessible from the floor or permanent work platform without the use of step ladders.

b. All interlock device wiring shall start out at and end at a terminal strip in the main cabinet. No device shall be wire directly to another device in series without returning to the main cabinet’s terminal strip first. All series wiring will take place at the terminal strip. Wiring should be done in a manner that allows for ease of access with minimal PPE as required by

NFPA 70.

c. Safety devices are prohibited to be PLC dependent or be included in any program where the input or output can be forced, or if the program is changed, updated, etc., could have any effect on the safety device setting or function. All safety devices shall be hard wired from the device or sensor to the flame safeguard controller directly. Wiring may pass through terminal strip(s).

d. Provide all necessary control system passwords, wiring diagrams, and step-by-step written instructions specific to that facility to COR to facilitate all interlock testing required by the VHA

Boiler Plant Safety Devices Testing Manual. The written

23 09 11 - 23 instructions shall include terminal and wire numbers for specific test where required.

e. If the system installed cannot be tested in accordance with the

VHA Boiler Plant Safety Devices Testing Manual the contractor shall provide a written step by step safety device test procedure(s) for the devices(s) that follow and meet the intent of the VHA Boiler Plant Safety Devices Testing Manual, submitted to VA CFM CSS and VHA OCAMES for review and approvals. The

Government reserves the right to reject any procedure and require the system device be replaced at no addition cost or time to the

Government.

3. Forced Draft Fan Motor Operation Interlock: Provide split ring current relays on each phase of power circuits to fan motor, required on all systems.

a. Provide push buttons to test each leg of the fan motor leads. The push buttons shall be mounted on the face of the cabinet, momentary contacts, wired in parallel with the current relays.

The current drop through the current relay when the push buttons contacts are closed shall trip the burner off at any firing rate.

b. For variable speed drives, provide signals to control system from

VFD fault and run contacts and signals from VFD shaft speed feedback to prove proper fan speed for purging, low fire ignition, and for each burner load point. Contractor to provide test procedure for review and approval.

c. Fully metered systems that measure and prove actual air flow at all firing rates may be used as a substitution. The contractor shall provide test procedures to prove the burner shuts down if proper air flow is not maintained or achieved. The procedures must be reviewed and approved by VA CFM CSS and VHA OCAMES.

d. Any disconnects or other power shut-off devices between the location of the interlock devices and the motor shall also shutdown the power supply to the burner management control system.

4. Forced Draft Fan Damper, Boiler or Economizer Flue Gas Outlet Damper

(if provided) Pre-Purge Position Interlock: Prove dampers wide open for pre-purge. Actuate sealed snap-action switches by levers attached directly to dampers or to damper linkages, which are pinned to prevent slippage. Parallel positioning systems may have the

23 09 11 - 24 interlock switches in the drive units. The switches are dedicated for the flame safeguard system and perform no other function or purpose and are make or break switches.

5. FGR Dampers (if provided) Position Interlock: Prove dampers positioned as required by burner manufacturer for pre-purge and firing. Actuate sealed snap-action switches by levers attached directly to dampers or to damper linkages, which are pinned to prevent slippage.

6. Pre-Purge Airflow Interlock:

a. Sense differential pressure between two points in combustion air system where the differential pressure at high fire is significant, such as several inches water column. There must be no intervening dampers. This is typically between the wind-box and boiler outlet.

b. Diaphragm-actuated snap-action switch designed for maximum system pressure, adjustable set point, graduated set point indicating scales.

c. UL listed, FM approved.

d. Provide air pressure sensing connections for test manometer so that air flow switch settings can be verified.

e. Trip point shall prove at least 80 percent of maximum airflow.

7. Combustion Air Proving Interlock:

a. Sense differential air pressure across the forced draft fan with no intervening dampers.

b. Diaphragm-actuated snap-action switch designed for maximum system pressure, adjustable set point, graduated set point indicating scales.

c. UL listed, FM approved. Provide switch designed for “false combustion air” feature on start-up interlock.

d. Provide air pressure sensing connections for test manometer so that switch settings can be verified. Demonstrate that trip point is within 10 percent of minimum differential pressure over the firing range of the burner.

8. High and Low Main Burner Fuel (Gas and Oil) And Low Igniter (Pilot)

Gas Pressure Interlocks:

a. Approvals: UL listed, FM approved assembly.

b. Solid-state sensor, automatic reset. Provide graduated set point indicator, switch position indicator, adjustable set point

23 09 11 - 25 coordinated with burner requirements either on the switch or as a part of the controller.

c. Gas pressure switch ratings: Sustained pressure capability shall exceed two times lock-up of nearest upstream regulator.

d. Oil pressure switch ratings: Sustained pressure capability shall exceed set pressure, plus accumulation, of oil pump safety relief valve. On heated oil system, sustained temperature capability shall exceed maximum operating temperature.

e. Low gas pressure switches shall include integral impulse dampener to reduce the effects of pressure dips during start-up. Use of external dampeners or snubbers is prohibited.

f. Switch Locations: Must be located where pressure is constant, as controlled by pressure regulator (if provided) on fuel train.

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