23 52 00.pdf

Tinker AFB, OK TAFB Technical Specifications 2019

April 2019 Page 1 Section 23 52 00

SECTION 23 52 00

HEATING BOILERS

This guide specification covers the requirements for packaged hot water and steam boiler systems (gas fired) of up to 20,000,000 Btuh output capacity. The hot water boiler systems operate at water temperatures below 250 degrees F and water working pressures less than 160 psi. The steam heating systems operate up to 15 psig.

PART 1 GENERAL

1.1 REFERENCES

The publications listed below form a part of this specification to the extent referenced. The publications are referred to within the text by the basic designation only. Current editions of references at the time of delivery order shall be used.

AIR MOVEMENT AND CONTROL ASSOCIATION INTERNATIONAL (AMCA)

AMCA 801 Industrial Process/Power Generation Fans:

Specification Guidelines

AMERICAN NATIONAL STANDARDS INSTITUTE (ANSI)

ANSI Z21.13/CSA 4.9 Gas-Fired Low Pressure Steam and Hot Water

Boilers

AMERICAN SOCIETY OF HEATING, REFRIGERATING AND AIR-CONDITIONING

ENGINEERS (ASHRAE)

ASHRAE 52.2 Method of Testing General Ventilation Air-

Cleaning Devices for Removal Efficiency by Particle Size

AMERICAN WATER WORKS ASSOCIATION (AWWA)

AWWA C606 Grooved and Shouldered Joints

AMERICAN WELDING SOCIETY (AWS)

AWS A5.8/A5.8M Specification for Filler Metals for Brazing and Braze Welding

AWS B2.2/B2.2M Specification for Brazing Procedure and

Performance Qualification

ASME INTERNATIONAL (ASME)

ASME B1.20.1 Pipe Threads, General Purpose (Inch)

ASME B1.20.2M Pipe Threads, 60 Deg. General Purpose

(Metric)

April 2019 Page 2 Section 23 52 00

ASME B16.11 Forged Fittings, Socket-Welding and Threaded

ASME B16.15 Cast Bronze Alloy Threaded Fittings Classes

125 and 250

ASME B16.18 Cast Copper Alloy Solder Joint Pressure

Fittings

ASME B16.20 Metallic Gaskets for Pipe Flanges - Ring-

Joint, Spiral Wound, and Jacketed

ASME B16.22 Standard for Wrought Copper and Copper Alloy

Solder Joint Pressure Fittings

ASME B16.26 Standard for Cast Copper Alloy Fittings for

Flared Copper Tubes

ASME B16.3 Malleable Iron Threaded Fittings, Classes 150 and 300

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

ASME B16.39 Standard for Malleable Iron Threaded Pipe

Unions; Classes 150, 250, and 300

ASME B16.4 Standard for Gray Iron Threaded Fittings;

Classes 125 and 250

ASME B16.5 Pipe Flanges and Flanged Fittings: NPS 1/2

Through NPS 24 Metric/Inch Standard

ASME B16.9 Standard for Factory-Made Wrought Steel

Buttwelding Fittings

ASME B31.1 Power Piping

ASME B31.5 Refrigeration Piping and Heat Transfer

Components

ASME B40.100 Pressure Gauges and Gauge Attachments

ASME BPVC SEC IV BPVC Section IV-Rules for Construction of

Heating Boilers

ASME BPVC SEC IX BPVC Section IX-Welding and Brazing

Qualifications

ASME BPVC SEC VIII D1 BPVC Section VIII-Rules for Construction of

Pressure Vessels Division 1

ASME CSD-1 Control and Safety Devices for Automatically

Fired Boilers

ASME PTC 10 Performance Test Code on Compressors and

Exhausters

April 2019 Page 3 Section 23 52 00

ASTM INTERNATIONAL (ASTM)

ASTM A105/A105M Standard Specification for Carbon Steel

Forgings for Piping Applications

ASTM A167 Standard Specification for Stainless and

Heat-Resisting Chromium-Nickel Steel Plate, Sheet, and Strip

ASTM A183 Standard Specification for Carbon Steel Track

Bolts and Nuts

ASTM A193/A193M Standard Specification for Alloy-Steel and

Stainless Steel Bolting Materials for High- Temperature Service and Other Special Purpose Applications

ASTM A234/A234M Standard Specification for Piping Fittings of

Wrought Carbon Steel and Alloy Steel for Moderate and High Temperature Service

ASTM A515/A515M Standard Specification for Pressure Vessel

Plates, Carbon Steel, for Intermediate- and Higher-Temperature Service

ASTM A516/A516M Standard Specification for Pressure Vessel

Plates, Carbon Steel, for Moderate- and Lower-Temperature Service

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

ASTM A536 Standard Specification for Ductile Iron

Castings

ASTM A653/A653M Standard Specification for Steel Sheet, Zinc-

Coated (Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed) by the Hot-Dip Process

ASTM B32 Standard Specification for Solder Metal

ASTM B62 Standard Specification for Composition Bronze or Ounce Metal Castings

ASTM B75 Standard Specification for Seamless Copper

Tube

ASTM B75M Standard Specification for Seamless Copper

Tube (Metric)

ASTM B813 Standard Specification for Liquid and Paste

Fluxes for Soldering of Copper and Copper Alloy Tube

April 2019 Page 4 Section 23 52 00

ASTM B828 Standard Practice for Making Capillary Joints by Soldering of Copper and Copper Alloy Tube and Fittings

ASTM B88 Standard Specification for Seamless Copper

Water Tube

ASTM B88M Standard Specification for Seamless Copper

Water Tube (Metric)

ASTM C155 Standard Specification for Insulating

Firebrick

ASTM C27 Fireclay and High-Alumina Refractory Brick

ASTM C34 Structural Clay Load-Bearing Wall Tile

ASTM C401 Alumina and Alumina-Silicate Castable

Refractories

ASTM D1784 Standard Specification for Rigid Poly(Vinyl

Chloride) (PVC) Compounds and Chlorinated Poly(Vinyl Chloride) (CPVC) Compounds

ASTM D2000 Standard Classification System for Rubber

Products in Automotive Applications

ASTM D596 Reporting Results of Analysis of Water

ASTM F1097 Mortar, Refractory (High-Temperature, Air-

Setting)

ASTM F1139 Steam Traps and Drains

COMPRESSED AIR AND GAS INSTITUTE (CAGI)

CAGI B19.1 Safety Standard for Compressor Systems

COPPER DEVELOPMENT ASSOCIATION (CDA)

CDA A4015 Copper Tube Handbook

EXPANSION JOINT MANUFACTURERS ASSOCIATION (EJMA)

EJMA Stds EJMA Standards

HYDRONICS INSTITUTE DIVISION OF GAMA (HYI)

HYI-005 I=B=R Ratings for Boilers, Baseboard

Radiation and Finned Tube (Commercial)

HYI-400 Radiant Floor Heating

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MANUFACTURERS STANDARDIZATION SOCIETY OF THE VALVE AND FITTINGS

INDUSTRY (MSS)

MSS SP-110 Ball Valves Threaded, Socket-Welding, Solder

Joint, Grooved and Flared Ends

MSS SP-25 Standard Marking System for Valves, Fittings, Flanges and Unions

MSS SP-58 Pipe Hangers and Supports - Materials, Design and Manufacture, Selection, Application, and Installation

MSS SP-69 Pipe Hangers and Supports - Selection and

Application (ANSI Approved American National Standard)

MSS SP-70 Gray Iron Gate Valves, Flanged and Threaded

Ends

MSS SP-71 Gray Iron Swing Check Valves, Flanged and

Threaded Ends

MSS SP-72 Ball Valves with Flanged or Butt-Welding Ends for General Service

MSS SP-78 Cast Iron Plug Valves, Flanged and Threaded

Ends

MSS SP-80 Bronze Gate, Globe, Angle and Check Valves

MSS SP-85 Gray Iron Globe & Angle Valves Flanged and

Threaded Ends

NATIONAL ELECTRICAL MANUFACTURERS ASSOCIATION (NEMA)

NEMA 250 Enclosures for Electrical Equipment (1000

Volts Maximum)

NEMA MG 1 Motors and Generators

NATIONAL FIRE PROTECTION ASSOCIATION (NFPA)

NFPA 211 Standard for Chimneys, Fireplaces, Vents, and

Solid Fuel-Burning Appliances

NFPA 31 Standard for the Installation of Oil-Burning

Equipment

NFPA 54 National Fuel Gas Code

NFPA 70 National Electrical Code

NFPA 85 Boiler and Combustion Systems Hazards Code

April 2019 Page 6 Section 23 52 00

UNDERWRITERS LABORATORIES (UL)

UL 1738 Venting Systems for Gas-Burning Appliances, Categories II, III and IV

UL 296 Oil Burners

UL 726 Oil-Fired Boiler Assemblies

UL 795 Standard for Commercial-Industrial Gas

Heating Equipment

UL Gas&Oil Dir Flammable and Combustible Liquids and Gases

Equipment Directory

1.2 SUBMITTALS

Government approval is required for submittals. Submit the following in accordance with Section 01 33 00 SUBMITTAL PROCEDURES:

SD-02 Shop Drawings

Detail Drawings

SD-03 Product Data

Materials and Equipment Spare Parts Water Treatment System Boiler Water Treatment Heating System Tests Fuel System Tests Unit Heaters Welding Qualifications Field Instructions Tests

SD-06 Test Reports

Heating System Tests Fuel System Tests Water Treatment Testing

SD-07 Certificates

Bolts Continuous Emissions Monitoring Energy Star

SD-10 Operation and Maintenance Data

Operation and Maintenance Instructions Water Treatment System

April 2019 Page 7 Section 23 52 00

1.3 QUALITY ASSURANCE

WELDING: Submit a copy of qualified welding procedures and a list of names and identification symbols of qualified welders and welding operators, at least 2 weeks prior to the start of welding operations. Boilers and piping shall be welded and brazed in accordance with qualified procedures using performance-qualified welders and welding operators. Procedures and welders shall be qualified in accordance with ASME BPVC SEC IX. Welding procedures qualified by others, and welders and welding operators qualified by another employer may be accepted as permitted by ASME B31.1. Notify the Contracting Officer 24 hours in advance of tests, and the tests shall be performed at the work site if practical. The welder or welding operator shall apply the personally assigned symbol near each weld made as a permanent record.

Structural members shall be welded in accordance with Section 05 05 23 WELDING, STRUCTURAL. Welding and nondestructive testing procedures for piping are specified in Section 40 05 13.96 WELDING PROCESS PIPING.

1.4 DELIVERY, STORAGE, AND HANDLING

Protect equipment delivered and placed in storage from the weather, humidity and temperature variations, dirt and dust, and other contaminants.

1.5 EXTRA MATERIALS

Submit spare parts data for each different item of material and equipment specified, after approval of the detail drawings and no later than 2 months prior to the date of beneficial occupancy. Submit Detail Drawings consisting of equipment layout including installation details and electrical connection diagrams; combustion and safety control diagrams; ductwork layout showing the location of supports and hangers, typical hanger details, gauge reinforcement, reinforcement spacing rigidity classification, and static pressure and seal classifications; and piping layout showing the location of guides and anchors, the load imposed on each support or anchor (not required for radiant floor tubing), and typical support details. Include on the drawings any information required to demonstrate that the system has been coordinated and will properly function as a unit and to show equipment relationship to other parts of the work, including clearances required for operation and maintenance. Include in the data a complete list of parts and supplies, with current unit prices and source of supply, and a list of the parts recommended by the manufacturer to be replaced after 1 and 3 years of service.

PART 2 PRODUCTS

In accordance with P.L. 109-58 (Energy Policy Act of 2005), Executive Order 13423, and Federal Acquisition Regulation (FAR) Section 23.203 energy consuming products and systems shall meet or exceed the performance criteria for ENERGY STAR®-qualified or FEMP-designated products as long as these requirements are nonproprietary.

The FEMP and ENERGY STAR product requirements are available on the web at www.eere.energy.gov/femp/procurement and www.energystar.gov/products.

Where ENERGY STAR or FEMP products are not applicable, energy consuming products and systems shall meet or exceed the requirements of ASHRAE 90.1.

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Include all equipment efficiencies on the equipment data submittals, and on the schedules of the as built drawing set.

2.1 MATERIALS AND EQUIPMENT

2.1.1 Standard Products

Provide materials and equipment which are the standard products of a manufacturer regularly engaged in the manufacture of the products and that essentially duplicate items that have been in satisfactory use for at least 2 years prior to bid opening. Equipment shall be supported by a service organization that is, in the opinion of the Contracting Officer, reasonably convenient to the site. Submit manufacturer's catalog data included with the detail drawings for the following:

a. Data showing model, size, options, etc., that are intended for consideration. Data submitted shall be adequate to demonstrate compliance with contract requirements. Data shall include manufacturer's written installation instructions and manufacturer's recommendations for operation and maintenance clearances for the following:

1) Boilers

2) Unit Heaters

3) Fuel Burning Equipment

4) Combustion Control Equipment

5) Pumps

6) Fittings and Accessories

7) Fuel Oil Storage System

8) Water Treatment System

2.1.2 Asbestos Prohibition

Asbestos and asbestos-containing products will not be allowed.

2.1.3 Nameplates

Secure a plate to each major component of equipment containing the manufacturer's name, address, type or style, model or serial number, and catalog number. Also, display an ENERGY STAR label as applicable. Each pressure vessel shall have an approved ASME stamp.

2.1.4 Equipment Guards

Belts, pulleys, chains, gears, couplings, projecting setscrews, keys, and other rotating parts exposed to personnel contact shall be fully enclosed or guarded in accordance with OSHA requirements. High temperature equipment and piping exposed to contact by personnel or where it creates a potential fire hazard shall be properly guarded or covered with insulation of a type specified. Catwalks, operating platforms, ladders, and guardrails shall be provided where shown and shall be constructed in accordance with Section 05 50 13 MISCELLANEOUS METAL FABRICATIONS and 05 51 33 METAL LADDERS.

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2.2 BOILERS

Each boiler shall have the output capacity in British thermal units per hour (Btuh) as indicated when fired with the specified fuels. The boiler shall be furnished complete with the gas burning equipment, boiler fittings and trim, automatic controls, forced or induced draft fan or natural draft/atmospheric burner as applicable, electrical wiring, insulation, piping connections, and protective jacket. The boiler shall be completely assembled and tested at the manufacturer's plant. Boiler auxiliaries including fans, motors, drives, and similar equipment shall be provided with at least 10 percent excess capacity to allow for field variations in settings and to compensate for any unforeseen increases in pressure losses in appurtenant piping and ductwork. However, the boiler safety devices shall not be sized for a 10 percent excess capacity. The boiler and its accessories shall be designed and installed to permit ready accessibility for operation, maintenance, and service. Boilers shall be designed, constructed, and equipped in accordance with ASME BPVC SEC IV. Each boiler shall be of the correct type and designed for water or steam service as required for each application or a specified in the project documents. The boiler capacity shall be based on the ratings shown in HYI-005 or as certified by the American Boiler Manufacturers Association, or American Gas Association.

Natural draft/atmospheric burners will not be used for any boiler exceeding 1,000,000 Btuh output.

2.2.1 Firetube Boiler

Boiler shall be self-contained, multipass, packaged type, complete with all accessories, mounted on a structural steel base. When the boilers are operating at maximum output, the heat input rates shall not be greater than 6,700 Btu/hr per square ft of fireside heating surface.

2.2.2 Watertube Boiler

The boiler shall be a standard type of water tube boiler. Boiler shall be self-contained, packaged type, complete with all accessories, mounted on a structural steel base.

2.2.3 Cast Iron Boiler

Boiler shall be of the rectangular, sectional type, self-contained, packaged type, complete with accessories, mounted on a structural steel base. Cast iron sections shall be free of leaks under all operating conditions. Access shall be provided to permit cleaning of internal tube surfaces.

2.2.4 Condensing Boiler

Each boiler shall be a self-contained packaged type, complete with accessories, mounted on a structural steel base or a steel base which is integral to the boiler shell. Each boiler shall conform to the commercial design used by the manufacturer and shall permit free thermal expansion without placing undue stress on any part of the boiler. Each boiler which experiences the formation of condensate within the flue gas shall be specifically designed for condensing application. Each boiler shall withstand the corrosive effects of condensate for each part which may be in

April 2019 Page 10 Section 23 52 00 contact with the condensate at all possible operating conditions. Each boiler shall be provided with a separate air intake, exhaust, and condensate drain. Each boiler shall be designed to withstand the water temperature differentials anticipated at the required operating conditions without experiencing any damage due to thermal shock.

The lower the return temperature of water entering the boiler, the higher the resulting boiler efficiency (see ASHRAE HVAC Equipment and Applications Handbook). The return water temperature should be at or below the dew point of the flue gas to result in the formation of condensate. This condition may not occur within a steam heating system. Therefore, condensing boilers should only be used for hot water service. In addition, the water distribution system and heating coils should be designed for higher temperature differentials.

Condensing boilers may be in the form of fire tube boilers with pulse combustion, copper fire tube boilers, or multiple heat exchanger boilers.

The military specifications concerning fire tube and water tube boilers do not apply to condensing boilers.

2.2.5 Modular Configuration

A modular configuration is a series of small cast iron type and/or condensing type boilers. The smaller boilers are manifolded together to provide heating for larger loads. This arrangement should be used and is typically considered to be an energy friendly and reasonably economical solution when heating load variances are expected.

Modular boilers shall be of the cast iron and condensing type. Modular boilers shall have the capability of independent operation. Upon failure of any module, the remaining modules shall be capable of operating at their designed capacity. The size of the individual modules shall be as indicated.

2.2.6 Hot Water Heating Boilers

Hot water heating boilers will operate at pressures not over 160 psi and at temperatures not above 1250 degrees F at or near the boiler outlet. If a pressure above 30 psi is selected, the boiler may be required to be manned 24 hours a day. Consult AR 420-49 for boiler attendance requirements.

Allow adequate space around each boiler to permit accessibility for operation, maintenance, and service (including space for tube removal). A minimum clearance of 4 feet around the boiler will be required unless modular boilers are specified.

The hot water heating boiler shall be capable of operating at the specified maximum continuous capacity without damage or deterioration to the boiler, its setting, firing equipment, or auxiliaries. The rated capacity shall be the capacity at which the boiler will operate continuously while maintaining at least the specified minimum efficiency.

The following shall be the minimum efficiency unless a life cycle cost analysis indicates that a change in equipment efficiency is warranted. If the result of the life cycle analysis recommends a higher efficiency, the designer should consult multiple boiler manufacturers to ensure that the desired efficiency is available and provide the higher efficiency product.

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Boilers with a capacity less than 300,000 Btuh shall have an Annual Fuel Utilization Efficiency of at least 85 percent.

Gas fired boilers with a capacity of greater than or equal to 300,000 Btuh shall have a thermal efficiency of at least 80 percent when fired at the maximum and minimum ratings allowed by the controls.

Oil fired boilers with a capacity of greater than or equal to 300,000 Btuh shall have a thermal efficiency of at least 83 percent when fired at the maximum and minimum ratings allowed by the controls.

Condensing boilers shall have an Annual Fuel Utilization Efficiency of at least 90 percent.

2.2.7 Steam Heating Boilers

Steam boilers will operate at pressures below 15 psi.

The boiler shall be provided with a water column with gauge glass and fittings including water column and gauge glass drain valves of the straight through type. The steam heating boiler shall be capable of operating at the specified maximum continuous capacity without damage or deterioration to the boiler, its setting, firing equipment, or auxiliaries. The rated capacity shall be the capacity at which the boiler will operate continuously while maintaining at least the specified minimum efficiency.

The boiler feed water piping shall contain a loop or trap. The bottom portion of the trap shall be below the anticipated water level within the boiler. All piping arrangements will be shown on the drawings.

Site conditions affect fan selection, boiler design, and stack design.

The feed water temperature shall be selected to avoid thermal shock.

Typical ranges are between 20 degrees F and 40 degrees F below the boiler outlet temperature. The boiler manufacturer should be consulted for proper selection. Select appropriate boiler types. Allow adequate space around each boiler to permit accessibility for operation, maintenance, and service (including space for tube removal). A minimum of 4 feet around the boiler will be required.

The contractor shall provide the efficiency shown below for the desired type of boiler, unless a life cycle cost analysis indicates that a change in equipment efficiency is warranted. If the result of the life cycle analysis recommends a higher efficiency, the contractor should consult multiple boiler manufacturers to ensure that the desired efficiency is available and provide the increased efficiency product accordingly.

Boilers with a capacity less than 300,000 Btuh shall have an Annual Fuel Utilization Efficiency of at least 85 percent.

Gas fired boilers with a capacity of greater than or equal to 300,000 Btuh and less than or equal to 2,500,000 Btuh shall have a thermal efficiency of at least 79 percent.

Gas fired boilers with a capacity greater than 2,500,000 Btuh shall have a thermal efficiency of at least 80 percent.

April 2019 Page 12 Section 23 52 00

2.3 FUEL BURNING EQUIPMENT

Boiler shall be designed to burn gas. Each boiler shall comply with Federal, state, and local emission regulations.

Include all the required data for proper design of the boiler.

Review the Clean Air Act Amendment of 1990 (CAAA) and other applicable Federal, state, and local regulations early in the design or selection phase to determine the appropriate emission limitations and monitoring requirements.

The CAAA does not require the application of low NOx burner (LNB) technology for boilers within the size range of this specification.

However, state implementation plans may place limits on NOx and particulates and more stringent requirements on SO2.

Consideration shall be given to the unique installation and space requirements of various emmision control or measurement systems.

2.3.1 Burners

2.3.1.1 Gas and Combination Gas-Oil Fired Burners and Controls

Burners shall be UL approved mechanical draft burners with all air necessary for combustion supplied by a blower where the operation is coordinated with the burner and natural draft/atmospheric burners. Burner shall be provided complete with fuel supply system in conformance with the following safety codes or standards:

a. Gas-fired units with inputs greater than 400,000 Btuh per combustion chamber shall conform to UL 795. Gas fired units less than 12,500,000 Btuh input shall conform to ANSI Z21.13/CSA 4.9. Single and multiple burner gas-fired units greater than or equal to 12,500,000 Btuh input shall conform to NFPA 85.

2.3.2 Draft Fans

Fans conforming to AMCA 801 forced-draft and induced-draft shall be furnished as an integral part of boiler design. Fans shall be centrifugal with backward-curved blades, radial-tip blades, or axial flow type. Each fan shall be sized for output volume and static pressure rating sufficient for pressure losses, excess air requirements at the burner, leakages, temperature, and elevation corrections for worst ambient conditions, all at full combustion to meet net-rated output at normal firing conditions, plus an overall excess air volume of 10 percent against a 20 percent static overpressure. Noise levels for fans shall not exceed 85 decibels in any octave band at a 3 foot station. Forced draft fan bearings shall be air cooled. Induced-draft fans shall be designed for handling hot flue gas at the maximum outlet temperature in the boiler. Induced draft fan housings shall be provided with drain holes to accommodate the drainage of condensation. Induced draft fan bearings shall be air-cooled or water-cooled. Induced draft fan scroll sheets and rotor blades shall have protective liners.

April 2019 Page 13 Section 23 52 00

2.3.2.1 Draft Fan Control

Forced-draft centrifugal fans shall have inlet vane controls or shall have variable speed control where indicated. Inlet vanes shall be suitable for use with combustion control equipment. Induced-draft centrifugal fans shall have outlet dampers and shall have variable speed control. Induced-draft fans shall have inlet vane controls. Axial propeller fans shall have variable propeller pitch control.

2.3.2.2 Draft Fan Drives

Fans shall be driven by electric motors. Electric motor shall be drip proof totally enclosed nonventilated or totally enclosed fan cooled or totally enclosed fan-cooled, suitable for installation in a Class II, Division 1, Group F, hazardous location conforming to NFPA 70. Motor starter shall be magnetic across-the-line reduced voltage start type with general purpose, watertight, dust-tight, or explosion-proof enclosure as required by application and shall be furnished with four auxiliary interlock contacts.

2.3.3 Draft Damper

Boilers shall be provided with manual or automatic dampers, draft hoods, or barometric dampers as recommended by the boiler manufacturer to maintain proper draft in the boiler. Draft damper shall be provided in a convenient and accessible location in the flue gas outlet from the boiler. Automatic damper shall be arranged for automatic operation by means of a damper regulator, furnace draft regulator, or damper motor.

Note: Normally, manual dampers are adequate for single boilers less than 2,000,000 Btuh capacity. Provide automatic dampers for modular boilers.

2.3.4 Ductwork

Air ducts connecting the forced-draft fan units with the plenum chamber shall be designed to convey air with a minimum of pressure loss due to friction. Ductwork shall be galvanized sheet metal conforming to ASTM A653/A653M. Ducts shall be straight and smooth on the inside with laps made in direction of air flow. Ducts shall have cross-break with enough center height to assure rigidity in the duct section, shall be angle iron braced, and shall be completely free of vibration. Access and inspection doors shall be provided as indicated and required, with a minimum of one in each section between dampers or items of equipment. Ducts shall be constructed with long radius elbows having a centerline radius 1-1/2 times the duct width, or where the space does not permit the use of long radius elbows, short radius or square elbows with factory-fabricated turning vanes may be used. Duct joints shall be substantially airtight and shall have adequate strength for the service, with 1-1/2 x 1-1/2 x 1/8 inch angles used where required for strength or rigidity. Duct wall thickness shall be 16 gauge (0.0598 inch) for ducts 60 inches or less and 12 gauge (0.1046 inch) for ducts larger than 60 inches in maximum dimension. Additional ductwork shall be in accordance with Section 23 00 00 AIR SUPPLY, DISTRIBUTION, VENTILATION, AND EXHAUST SYSTEM.

April 2019 Page 14 Section 23 52 00

2.4 COMBUSTION CONTROL EQUIPMENT

Controls for facilities with operating Energy Monitoring and Control Systems (EMCS) will be specified to be compatible with existing EMCS controls.

Ignore references to multiple boilers if a single boiler is used.

If steam boilers are not utilized, all references to steam pressure controllers shall be ignored. If hot water boilers are not utilized, all references to water temperature controllers shall be ignored.

Combustion control equipment shall be provided as a system by a single manufacturer. Field installed automatic combustion control system shall be installed in accordance with the manufacturer's recommendations and under the direct supervision of a representative of the control manufacturer.

The boiler water temperature shall be controlled by a water temperature controller. The boiler pressure shall be controlled by a steam pressure controller. The equipment shall operate either electrically or pneumatically. On multiple boiler installations, each boiler unit shall have a completely independent system of controls responding to the load and to a plant master controller. If recording instruments are provided, a 1 year supply of ink and 400 blank charts for each recorder shall be furnished.

2.4.1 Pneumatic Controls

If pneumatic operation is provided, a regenerant desiccant air dryer unit shall be provided. Boiler shall shut down on loss of control air pressure.

Pneumatic control systems shall conform to CAGI B19.1. Air filter regulator sets shall be installed at each control valve and transmitter in the system.

The master air filter regulator set on the control panel shall be the dual type where one side can be cleaned and repaired while the other is operating. Exterior control air piping and devices shall be protected from freezing.

2.4.1.1 Air Compressor Unit

The air compressor unit shall be electric-motor driven, polytetrafluoro-ethylene or carbon ring type automatic air compressor. The compressor unit shall be sized to run not more than 60 percent of the time when all controls are in service. The air compressor unit shall be complete with necessary accessories including automatic pressure control equipment, relief valves, check valves, air filters, moisture traps, and a receiver with ample capacity for emergency operation of the controls for 15 minutes after compressor shutdown. Compressor speed shall not exceed 900 rpm. Motor speed shall not exceed 1750 rpm. The compressor air intake shall be provided with a low drop type air suction filter/silencer suitable for outdoor installation.

2.4.1.2 Air Receiver

The air receiver shall be constructed in accordance with ASME BPVC SEC VIII D1 for unfired pressure vessels for( 200 psi) working pressure, and shall be equipped with inlet and outlet connections, valved drain connection, April 2019 Page 15 Section 23 52 00 minimum( 6 inch) dial pressure gauge, pop safety valves, and regulator connections.

2.4.2 Electrical controls

Electrical control devices shall be rated at 120 0r 24 volts and shall be connected as specified in Section 26 20 00 INTERIOR DISTRIBUTION SYSTEM.

2.4.3 Water Temperature Controller

If hot water boilers are not utilized, the following paragraph may be ignored.

The controller shall be of sturdy construction and shall be protected against dust and dampness. The thermostatic element shall be inserted in a separable socket installed in the upper part of the boiler near the water outlet or in the boiler return piping. Fixed position (on-off) and three position (high-low-off) controller shall operate on a 10 degree F differential over an adjustable temperature range of approximately 140 to 220 degrees F. Modulating controllers shall control the fuel burning equipment to maintain set boiler water temperature within 2 percent.

Controller shall be furnished with necessary equipment to automatically adjust the setting to suit the outside weather conditions. The outside air reset controller shall be operated in such a manner that the operating temperatures required by the boiler manufacturer are not compromised.

Consideration shall be given to the utilization of outside air reset controls. Outside air reset control is typically used for boilers whose primary loads are due to space heating applications. Information on outdoor air reset controls for space heating application is located in Section 23 09

23 LONWORKS DIRECT DIGITAL CONTROL FOR HVAC AND OTHER LOCAL BUILDING SYSTEMS

and UFC 3-410-02A or UFC 3-540-02N. Consideration will be given to the use of control based on return water temperature rather than supply water temperature.

2.4.4 Steam Pressure Controller

If steam boilers are not utilized the following paragraph may be ignored.

The controller shall be of sturdy construction and shall be protected against dust and dampness. The sensing elements of the steam controller shall be in direct contact with the steam. Fixed position (on-off) and three position (high-low-off) type controllers shall operate on a 1 pound differential over a pressure range of 0 to 15 psig. Modulating controllers shall automatically maintain, within 2 percent, the desired steam pressure by regulating the burner.

2.4.5 Boiler Plant Master Controller

If only one boiler is utilized, the following paragraph may be ignored.

A master controller shall be provided for applications involving multiple boilers and for boilers arranged in a modular configuration. A master controller shall be provided for applications involving multiple boilers and for boilers arranged in a modular configuration.

April 2019 Page 16 Section 23 52 00

A boiler plant master controller, sensitive to a temperature transmitter in the return water header for the boiler or steam pressure transmitter in the boiler steam discharge header shall be furnished to provide anticipatory signals to all boiler controllers. Boiler controllers shall react to anticipatory signals from the plant master controller as necessary in response to the boiler temperature or pressure indication to maintain the preset temperature or pressure. An automatic-manual switch shall be provided to allow the sequence of boiler loading to be varied to distribute equal firing time on all boilers in the plant. The plant master controller shall load the boilers one at a time as the plant load increases.

2.4.6 Boiler Combustion Controls and Positioners

a. Gas boiler units shall be provided with fixed rate (on-off), three position (high-low-off), or modulating combustion controls with gas pilot or spark ignition. Modulating controls shall be provided with a means for manually controlling the firing rate.

b. Modulating control function shall be accomplished using positioning type controls. Air flow ratio and fuel control valve shall be controlled by relative positions of operative levers on a jackshaft responding to a water temperature controller or steam pressure controller. Positioning type combustion control equipment shall include draft controls with synchronized fuel feed and combustion air supply controls, while and shall maintain the proper air/fuel ratio.

The desired furnace draft shall be maintained within 0.01 inch of water column.

d. Fixed rate on-off or High-low-off controls for boilers with capacities up to 2,000,000 Btuh shall use a water temperature controller in a temperature well in direct contact with the water or steam pressure controller in direct contact with the steam.

2.4.7 Combustion Safety Controls and Equipment

Provide feed water regulator with low-water cutoff on close coupled boilers (i.e. short supply and return lines with low pick-up losses) under 4,000,000 Btuh gross output with no process loads. Provide pump controller with low-water cutoff for all other boilers. Low-water cutoff will require a manual reset unless a supplementary low-water cutoff is provided. A supplementary low-water cutoff is required for boilers utilizing a pumped condensate return system. State and local codes may also require supplementary low-water cutoffs. When a supplementary low-water cutoff is provided, it will require manual reset and the initial low-water cutoff will not require manual reset.

Include the manually operated shutoff switch in the controls drawings, set point schedules and plans.

Combustion safety controls and equipment shall be UL listed, microprocessor-based distributed process controller. The system shall include mounting hardware, wiring and cables, and associated equipment. The controller shall be mounted completely wired, programmed, debugged, and tested to perform all of its functions. The controller shall process the signals for complete control and monitoring of the boiler. This shall include maintaining boiler status, starting and stopping all control functions, sequencing control

April 2019 Page 17 Section 23 52 00 functions and signaling alarm conditions. The program shall be documented and include cross references in description of coils and contacts.

Microprocessor shall be able to perform self diagnostics and contain a message center to provide operator with status and failure mode information.

Controllers for each boiler shall be mounted on a separate, free standing panel adjacent to the boiler or for packaged boilers on the boiler supporting structure. Control systems and safety devices for automatically fired boilers shall conform to ASME CSD-1. Electrical combustion and safety controls shall be rated at 120 volts, single phase, 60 Hz and shall be connected as specified in Section 26 20 00 INTERIOR DISTRIBUTION SYSTEM. A( 4 inch) diameter alarm bell shall be provided and shall be located where indicated or directed. The alarm bell shall ring when the boiler is shut down by any safety control or interlock. Indicating lights shall be provided on the control panel. A red light shall indicate flame failure, and a green light shall indicate that the main fuel valve is open. The following shutdown conditions shall require a manual reset before the boiler can automatically recycle:

a. Flame failure.

b. Failure to establish pilot flame.

c. Failure to establish main flame.

d. Low-water or supplementary low-water cutoff.

e. High temperature cutoff or High pressure cutoff.

2.4.7.1 Low-water Cutoff

If state or local codes or regulations require a second cutoff, a separate supplementary low-water cutoff of the float type or electrode type may be provided. Delete supplementary low-water cutoff if second cutoff is not required. Delete feedwater regulator and pump controller for water heating systems.

Low water cutoff shall be float actuated switch or electrically actuated probe type low-water cutoff. Float chamber shall be provided with a blow-down connection. Cutoff shall cause a safety shutdown and sound an alarm when the boiler water level drops below a safe minimum level. A safety shutdown due to low water shall require manual reset before operation can be resumed and shall prevent recycling of the burner. The cutoff shall be in strict accordance to the latest version of code, ASME CSD-1 Controls and Safety Devices for Automatically Fired Boilers.

a. Feedwater Regulator with Low-Water Cutoff: Regulator shall be an approved design sized for the application. A regulator shall be provided for each boiler. The feeder shall be so arranged that water will be fed to the boiler automatically when the water level in the boiler drops below a preset point and will actuate the alarm bell when the water level reaches the low danger point. The boiler feeder shall be arranged so that the burner and forced-draft fan will stop whenever the water level drops below a preset danger point. The boiler feeder shall be constructed so that the feedwater valve and seat are isolated from the float chamber to prevent overheating of the feed water and precipitation of scale on either the valve or seat. Each float

April 2019 Page 18 Section 23 52 00 mechanism, valve, and seat shall be constructed of an approved, durable, corrosion-resistant steel alloy. Valve seats shall be removable and renewable. The regulator shall be equipped with a large, self-cleaning strainer. The drain valve on the regulator shall be the gate or other straight-through type.

b. Pump Controller with Low-Water Cutoff: Controller shall be a design approved by the boiler manufacturer. A pump controller shall be provided for each boiler which is used for space heating and process steam loads or long distribution lines. Pump controller shall control the operation of the burner, forced-draft fan, and pump. Pump controller and low-water cutoff shall have a float-operated mercury switch arranged to start and stop the pump at preset boiler water levels. If the water level in the boiler reaches the low danger point, a second mercury switch shall shut down the burner and actuate the alarm bell.

c. Supplementary Low-Water Cutoff: Supplementary low-water cutoff of the electrically operated probe type or float activated type shall be provided in addition to the low-water cutoff required above on each boiler. Supplementary low-water cutoff shall be mounted directly in the boiler shell and shall be set below the low-water cutoff required above.

2.4.7.2 Water Flow Interlock

Ignore this paragraph if a hot water boiler is not utilized.

Hot water boiler limit controls shall be provided to include protection for low boiler water flow and high boiler water temperature. The limit controls shall be interlocked with the combustion control system to effect boiler alarm and shutdown. The controls shall not allow boiler startup unless hot water flow is proven.

2.5 PUMPS

2.5.2 Hot Water and Boiler Circulating Pumps

Boiler and hot water circulating pumps must be selected at the most efficient point of the pump curve which will generally lie on the sloped portion of the curve.

If separate pumps are not needed to provide water flow to the boilers, delete the requirement for boiler circulating pumps. The flow switch or pressure switch will only be needed for the pump which provides flow through the boiler. Pipe supported pumps are typically available up to 2HP. Close-coupled pumps are typically available up to 5HP.

Circulating pumps for hot water shall be electrically driven single-stage centrifugal type and have a capacity not less than indicated. Boiler circulating pumps shall be supported on a concrete foundation with a cast iron or structural steel base and shall be closed-coupled shaft or flexible-coupled shaft. The boiler circulating pumps shall be horizontal split case or vertical split case type. Hot water circulating pumps shall be supported on a concrete foundation with a cast iron or structural steel base and shall have a closed-coupled shaft or flexible-coupled shaft. The hot water

April 2019 Page 19 Section 23 52 00 circulating pumps shall be horizontal split case or vertical split case type. The pump shaft shall be constructed of corrosion resistant alloy steel, sleeve bearings and glands of bronze designed to accommodate a mechanical seal, and the housing of close-grained cast iron. Pump seals shall be capable of withstanding 240 degrees F temperature without external cooling. The motor shall have sufficient power for the service required, shall be of a type approved by the manufacturer of the pump, shall be suitable for the available electric service, and shall conform to the requirements of paragraph ELECTRICAL EQUIPMENT. Each pump suction and discharge connection shall be provided with a pressure gauge as specified.

The boiler or hot water circulating pump discharge heater shall be provided with a flow switch or pressure switch. Flow switch unit shall be a self-contained swinging vane type to indicate fluid flow. Pressure switch unit shall be a self-contained snap action type to indicate fluid pressure.

Switch shall be a SPDT with 120-volt, 15-ampere rating.

2.5.3 Condensate Pumping Unit

Ignore this paragraph if hot water is utilized.

If steam is utilized, only one type of condensate return unit will be required and the vacuum pumping unit shall be deleted.

Each pump shall have a capacity not less than that indicated when discharging against the specified pressure. The minimum capacity of the tank shall be as indicated. The condensate pumping unit shall be the duplex horizontal shaft or vertical shaft type as indicated. The unit shall consist of one pump with electric motor drive, and a single receiver, all mounted on a suitable cast-iron or steel base. The motor may be mounted on the top of the receiving tank. Pump shall be the centrifugal or turbine type, bronze-fitted throughout, with impellers of bronze or other approved corrosion-resisting metal. Pump shall be free from air binding when handling condensate of temperatures up to 200 degrees F. Pump shall be directly connected to suitable drip-proof enclosed motors. Receiver shall be cast iron or not less than 3/16 inch thick black iron or steel and shall be provided with all the necessary reinforced threaded openings, including condensate return, vent, overflow, and pump suction connections. Inlet strainer shall be provided either integral in the tank or separate in the inlet line to the tank. Vent pipe shall be galvanized steel, and the fittings shall be galvanized malleable iron. Vent pipe shall be extended through the roof and shall be properly flashed. The pump, motor, and receiving tank may be mounted on a single base with the receiver piped to the pump suctions. A gate valve and check valve shall be provided in the discharge connection from each pump and a strainer and gate valve shall be provided in the suction line to each pump except where pumps are directly mounted on top of the receiver.

2.5.3.1 Controls for Space Heating Steam Loads Only

For loads where space heating is only part of the steam load, ignore this paragraph.

An enclosed float switch complete with float mechanisms shall be installed in the head of the receiver. Each condensate pump shall be controlled by a float switch which shall automatically start the motor when the water in the receiving tank reaches the high level and stop the motor when the water reaches the low level. The motors shall be provided with magnetic across-

April 2019 Page 20 Section 23 52 00 the-line starters equipped with general-purpose enclosures and three-position, "Manual-Off-Automatic" selector switches in the cover. Automatic alternator shall be provided for duplex units.

2.5.3.2 Space Heating and Steam Loads or Distribution Lines

For space heating loads only applications, ignore this paragraph and use above paragraph (2.5.3.1) instead.

The condensate pump shall be provided with an approved float-actuated valve or water feeder in the cold-water makeup connection either external to or integral with the receiver. Where a de-aerating feedwater heater is not included, the condensate pumping unit shall be controlled automatically by a pump controller with low-water cutout on each boiler. The pump controller and low-water cutout shall have two float-operated mercury switches arranged to start and stop the condensate pump at preset boiler water levels. One switch shall control the operation of the condensate pump by starting the pump when the water in the boiler reaches a preset low level and by stopping the pump when the water in the boiler rises to a preset high level. The second switch shall ring an alarm bell and simultaneously shut down the burner. Relays shall be provided if necessary. A minimum 4 inch alarm bell with bell-ringing transformer shall be installed where directed. A gate valve and a check valve or a stop-check (nonreturn) valve shall be installed in the feed line between the boiler and the pump adjacent to the boiler connection. The condensate pump motor shall be provided with a magnetic, across-the-line starter equipped with thermal-overload protection conforming to the requirements of paragraph ELECTRICAL EQUIPMENT. Where two or more boilers are provided, a pump controller and low-water cutout shall be installed at the normal waterline of each boiler. An automatic feed valve shall be installed in the feed line to each boiler. When any boiler requires water, the pump controller shall open the feed valve by actuating an end switch which, in turn, operates the condensate pump. When the normal water level is restored, the pump controller shall close the feed valve, and the end switch of the valve shall stop the condensate pump.

2.5.3.3 Rating and Testing

The pump manufacturer shall submit a certified test report covering the actual test of the unit and certifying that the equipment complies with the indicated requirements.

2.5.4 Vacuum Pumping Unit

Ignore this paragraph if hot water is utilized.

The vacuum pumping unit shall be a combination air removal and condensate return unit consisting of a single pump, electric motor, and receiving tank or pumps, electric motors, and other functioning parts in duplicate and a single receiving tank as indicated. Two interconnected single units will be acceptable in place of a duplex unit. The unit shall be arranged for automatic operation. Where duplicate pumps are used, one pump shall serve as a standby. Where it is standard with the manufacturer, separate pumps may be used for air removal and condensate return if both pumps are mounted on a common receiver. The receiver shall be constructed of cast iron, or of not less than 3/16 inch thick black iron or steel. The pumping unit shall be bronze fitted throughout with bronze shafts or with shafts protected by

April 2019 Page 21 Section 23 52 00 bronze sleeves. Pumps, motors, and receiver shall be mounted on a single base and provision shall be made for catching the drip from the stuffing boxes. Accessories shall consist of a compound gauge, a pressure gauge inlet strainer, thermometer, water level gauge with stopcocks, adjustable vacuum relief valve, air discharge and condensate discharge check valves, and companion flanges for all flanged connections. The discharge line from each pump shall be provided with a nonslam check valve and a globe valve.

Each motor shall have a dripproof-type enclosure. Fully automatic controls shall be provided for each pump motor.