RFI-Questions.pdf

Request for Information Building 008: Replace Boilers and Associated Heating System Repairs Food Animal Environmental Systems Research (FAESR) USDA-ARS, Bowling Green, KY Solicitation 12505B24R0021

Question 1: Do the superintendent, SSHO, and QC manager need to be 3 separate individuals?

A: USDA: Three (3) individuals are required. However, all three individuals are not required to be on site full time. The only individual required to be on site full time is the Site Superintendent. The Quality Control and SSHO shall be on site, as required per the Contractor’s QC and Safety plans.

Question 2: If the building is occupied throughout the project, how many people will be in the building?

A: USDA: Building will be occupied throughout the project. Contractors should anticipate that one to three people (USDA staff) will normally be in the building.

Question 3: Are there any phase requirements?

A: USDA: As indicated in General Note #2 and General Note #5 on Sheet 2, 3 and 4; the specified work shall be performed when warm outside weather conditions are anticipated such that the need for heating is limited to the greatest extent possible and the specified work shall be sequenced and performed in a manner to minimize downtime of the building’s heating system. See general notes for additional information.

Question 4: Are there any temporary heating / cooling requirements?

A: USDA: See response to Question 3 and Question 11.

Question 5: Will after hours work be allowed?

A: USDA: Normal working hours for the facility shall be considered 8 am to 5 pm, Monday through

Friday (except for federal holidays). Contractor’s proposal shall be based on performing the work of this project within normal working hours of the facility.

Question 6: Can the period of performance be extended after award once the material/equipment lead times are confirmed due to current market conditions for the equipment for this project?

A: USDA: Period of performance shall be extended to 270 days.

Question 7: Will the site visit sign in sheet be made available?

A: USDA: Please see “site visit sign-in” sheets that follow.

Question 8: Can you share the current preventative maintenance contact information?

A: USDA: The USDA has not engaged one specific vendor for maintenance and repairs on the existing heating system of the facility.

Question 9: Can you share the current controls contractor contact information?

A: USDA: USDA has not engaged one specific vendor for maintenance and repairs to the building control system. See Government Clarification 12 below for additional information.

Question 10: Please provide the current fire alarm contractor information.

A: USDA: Existing fire alarm system is a Johnson Controls system. USDA has not engaged one specific vendor for maintenance and repairs on the fire alarm system.

Question 11: Plans call for disconnecting exhaust and supply ducts from louvers. Are there specific provisions to maintain the building pressure while disconnected?

A: USDA: The project does not include any specific provisions to maintain building pressure except for the limiting the shutdown of building exhaust to the greatest extent possible. Project Drawings indicate the disconnecting / re-connecting of exhaust ductwork from louvers, see Sheet 2 of Project Drawings. As indicated in Note #4 and #5 of “General Notes – Building Exhaust System”; the specified work shall be sequenced and performed in a manner to minimize downtime of the building’s exhaust system. Existing air handler shall remain operational during the performance of the specified work.

Government Clarification 12 (Reference Sheet 2 – Keyed Note #16):

A: USDA: Existing building control system controller is Vykon by Tridium (Jace Controller). The existing controller has a non-functional display / interface unit and USDA does not have administrative level credentials available for Contractor’s use. The following scope shall be performed to provide properly functioning controller:

Contractor shall replace display / interface unit with new, new display shall be 100% compatible with the existing controller.

Contractor shall connect to and “unlock” existing controller (with assistance from Tridium support team) and re-set administrative level credentials.

Administrative level credentials shall be provided to appropriate USDA staff.

Contractor shall provide software update to latest available version, including providing updated licensing agreement.

Contractor shall provide thorough review of existing controller installation and shall confirm and document existing control sequences and existing points available at the existing controller installation. Contractor shall submit a report to USDA of the findings from this effort.

Contractor shall integrate new boiler(s) into the existing building controller to provide the control and monitoring the boilers and associated equipment as indicated in the Statement of Work.

All work performed at the existing building controller shall be performed by a qualified technician(s) who are trained and experienced in Tridium controllers.

Government Clarification 13 (Reference Project Specification – Section 23 52 16):

A: USDA: Add attached specification section “23 52 16 – Hot Water Condensing Boilers” (this specification section was omitted in the Statement of Work).

Government Clarification 14:

A: USDA: Contractor shall furnish and provide glycol in the renovated hot water heating system.

See Specification Section 23 52 16 for additional information.

Question 15: Would you consider an alternate brand boiler? Reason: the boilers spec are special order and very difficult to get parts for. If we went with a more common and in my opinion better stainless-steel boiler, they are more readily available and parts are easier to obtain. Response:

A: USDA: Basis-of-design products are indicated in the Statement of Work to convey a specified standard of quality and salient characteristics desired but are not to be considered a single-source specification. Contractor-proposed equals will be considered.

The Contractor must compare and validate that quality and salient characteristics are equal and approve the proposed equal products prior to submission for Government review and approval. Additional work required to incorporate Contractor-proposed equals shall be at the Contractor’s expense.

Owner will review all Contractor-proposed equal equipment, materials, manufacturers, or installation. It shall be the Contractor’s burden to furnish all documentation and / or samples to show equality with specified items. Owner’s decision on equality is final.

Manufacturers / products that are submitted as “Approved Equal” are reviewed during the shop drawing process, not during bidding.

Question 16: The Base Bid mentions control work for boilers. Does that mean an entirely new DDC/ BMS system? Or to tie into the existing system? A new DDC/ Building Management System can be done, however, of course that would be a large difference in price.

A: USDA: See Government Clarification 12 for additional information on building control system.

Question 17: We can easily get the boilers updated in stages to not lose heat within 90 days of award.

However, if we do the base bid plus all the options, 90 days is feasible but a bit difficult. Could we have for example 90 days for base bid and another 120 days for options. That way we know we are covered for the special order items that may be 60+ days out.

A: USDA: See response to Question #3 and Question #6 above.

Government Clarification 18 – Reference Equipment Schedule on Sheet 2 of Project Drawings.

A: USDA: Ratings indicated in Equipment Schedule of Sheet 2 of Project Drawings match the ratings indicated in the equipment schedule(s) of the facility’s original construction drawings. New boilers shall provide the output rating and flow characteristics of the originally intended boilers (Note: Output rating indicated in Equipment Schedule is Gross Output, Net Output shall be nominal 599 MBH). Basis of Design for new boilers are Thermal Solutions “APEX 725” series.

Government Clarification 19 – Reference Keyed Note #2 on Sheet 2 of Project Drawings.

A: USDA: Contractor shall expand / enlarge existing concrete equipment pad as needed for the installation of new boiler equipment. Expanded equipment pad shall provide 3” apron around boiler(s). Concrete for expanded equipment pad shall be 4000 psi, stone aggregate, normal weight concrete at 28 days. Contractor shall roughen existing floor slab and apply bonding agent within footprint of pad expansion.

Government Clarification 20 – Reference Equipment Schedule on Sheet 2 of Project Drawings.

A: USDA: See Equipment Schedule on Sheet 2 of Project Drawings; Pump 1b shall be rated for 35 gpm at 25 ft of head in lieu of the 70 gpm indicated.

Food Animal Environmental Systems Research

HOT WATER CONDENSING BOILERS 23 52 16- 1

SECTION 23 52 16 – HOT WATER CONDENSING BOILERS

PART 1 - GENERAL

1.1 SUMMARY

A. This Section includes the following:

1. Hot water condensing boiler(s) and associated components for indoor space-heating application.

1.2 REFERENCES

A. Intertek (ETL):

1. ETL certified to ANSI Z21.13/CSA 4.9.

B. American Society of Mechanical Engineers:

1. ASME Section IV - Boiler and Pressure Vessel Code - Heating Boilers

2. ASME CSD-1 – Controls and Safety Devices for Automatically Fired Boilers

C. American Society of Heating Refrigeration, and Air Conditioning

1. ASHRAE: Standard 90.1 Energy Standard for Buildings

D. American National Standards Institute

1. ANSI Z21.13 – Gas Fired Low Pressure Steam and Hot Water Boilers

E. Hydronics Institute, Division of Air Conditioning, Heating, and Refrigeration Institute:

1. BTS-2000: Testing Standard to Determine Efficiency of Commercial Space Heating

Boilers

F. National Fire Protection Association:

1. NFPA 54 – National Fuel Gas Code (ANSI Z223.1)

1.3 SUBMITTALS

A. Product Data: Include capacities, accessories, and options included with boiler units, electrical characteristics, weight and mounting loads.

B. Shop Drawings: General layout, dimensions, size and location of all required connections.

C. Manufacturer’s installation and start-up instructions.

D. Operation and maintenance data, including associated manual.

HOT WATER CONDENSING BOILERS 23 52 16- 2

1.4 QUALITY ASSURANCE

A. Use skilled workers, trained and experienced in the necessary crafts, and who are completely familiar with the requirements and methods needed for proper performance of the work described herein.

1.5 DELIVERY, STORAGE, AND HANDLING

A. Accept equipment and accessories in factory shipping packing. Inspect for damage. Keep boiler in vertical position from time of delivery to final installation, as required / recommended by manufacturer.

B. While stored, all equipment shall be protected from external elements such as inclement weather, job site construction activities, etc.

1.6 WARRANTY

A. Heat Exchanger: 10-year warranty.

B. All other parts: 1-year warranty.

PART 2 - PRODUCTS

2.1 ACCEPTABLE MANUFACTURERS

A. Manufacturers: Subject to compliance with requirements, provide products by one of the following:

1. Thermal Solutions “Apex” Series

2. Approved Equal.

2.2 GENERAL REQUIREMENTS

A. Description: The boiler shall be assembled, fire-tested and shipped as a factory-packaged unit, complete with jacket, gas manifold, burner and controls mounted & wired, with boiler connections specified in this Section.

1. Physical dimensions of new furnished boiler shall allow placement and installation in ex-isting mechanical room and on associated existing housekeeping pad and shall provide the manufacturer’s recommended clearances.

2. The boiler shall be constructed in conformance to ASME Section IV, ASME CSD-1, and ANSI Z21.13. The boiler shall bear the ASME “H” stamp with a maximum allowable working pressure (MAWP) of 160 PSI. Pressure vessel shall be subjected to a hydrostatic pressure test of 240 PSIG at the factory before shipment.

HOT WATER CONDENSING BOILERS 23 52 16- 3

3. The boiler shall be an ultra-high efficiency condensing boiler with a pressure vessel, con-structed of stainless steel, which shall not require a refractory combustion chamber.

4. The boiler shall be equipped with an integral pre-mix, metal-mesh type forced draft burner incorporating full modulation with 5:1 turndown.

5. The boiler gas valve will be designed with zero pressure regulation and equipped with a variable speed blower system to precisely control the fuel/air mixture, providing fully mod-ulating firing rates for maximum efficiency.

6. All piping and wiring connections shall be located on the left-side of the boiler. Connec-tions include: supply / return water connections, relief / drain tapping, condensate trap drain, and gas valve inlet connection. Condensate trap shall have a factory supplied com-pression fitting. A factory supplied drain valve and oversized relief valve shall be provided with the boiler(s).

7. The flue passages and combustion chamber shall be accessible from the front of the boiler for cleaning.

8. The boiler shall be provided with a heavy duty 20 gauge steel jacket with a rust resistant powder coat finish. Jackets made of plastic or resin material shall not be acceptable. The boiler jacket shall contain an internal electrical cabinet for power and limit circuit wiring, providing a clean finished look when the jacket is installed. Furthermore, all electrical and control components shall be mounted on a pullout-tray, providing easy access to wiring terminals, controls and 360 view of all wiring components. Individual lift-off jacket front panel may be installed after system piping and wiring to allow ease of access to the pressure vessel.

9. The electrical components shall be separated from incoming combustion air gas, which may contain excess humidity, dust and other contaminants brought through ducted com-bustion air.

10. A polypropylene condensate trap with a float-actuated shut-off switch shall be located within the boiler jacket and beneath the heat exchanger drain pan. The float-actuated shutoff switch must be located upstream from any bends in the condensate trap. Float switches located on the downstream side of the condensate trap shall not be acceptable due to the possibility of blockages occurring in the trap bends. The float-actuated switch shall be offset from the condensate drip to prevent mineral build-up from interfering with the switch actuation.

HOT WATER CONDENSING BOILERS 23 52 16- 4

2.3 BOILER CONTROL SYSTEM / BOILER TRIM / AIR CONNECTIONS

A. Provide a manufacturer furnished boiler control system, supplied as part of a factory-assembled and tested burner control cabinet, to provide safety interlocks and water temperature control:

1. The control system shall be fully integrated into the boiler control cabinet and incorporate single and multiple boiler control logic, inputs, outputs and communication interfaces.

The control system shall coordinate the operation of up to eight (8) fully modulating hot water boilers and circulation pumps. The control system shall simply control boiler mod-ulation and on/off outputs based on the boiler water supply temperature and an operator-adjusted setpoint. However, using parameter menu selections, the control system shall allow the boiler to respond to remote system water temperature and outside air tempera-tures with domestic hot water priority (DHWP) and warm weather shut down (WWSD) or building automation system (BAS) firing rate demand, remote setpoint or remote start/stop commands.

2. Using PID (proportional-integral-derivative) based control, the remote system water tem-perature shall be compared with a setpoint to establish a target boiler firing rate. If the secondary loop flow speed is greater than the primary loop flow speed, firing rate is in-creased in response to the decrease in secondary loop temperature. When the remote sys-tem temperature is near the boiler high limit temperature, the boiler supply sensor shall limit the maximum boiler supply temperature to prevent boiler high limit events. Alter-nately, using parameter menu selections, the control system shall allow the boiler to re-spond directly to boiler supply temperature and setpoint to establish a target boiler firing rate while remote system water temperature is used for display purposes only. Each boiler’s fuel flow control valve shall be mechanically linked to the air flow control device to assure an air rich fuel/air ratio. All the automated logic required to ensure that pre-purge, post-purge, light-off, and burner modulation shall be provided.

3. When the controller is in the local control mode, the control system shall establish the setpoint based on outside air temperature and a reset function curve, or be manually ad-justed by the operator. When enabled, the setpoint shall be adjusted above a preset mini-mum setpoint upon sensing a domestic hot water demand contact input. When in remote mode, the control system shall accept a Modbus or 4-20mAdc remote setpoint or firing rate demand signal from an external BAS.

4. Multiple boilers shall be modulated in “Unison” (all at the same firing rate). The control system shall utilize both water temperature and boiler firing rate percent to start and stop the boilers and shall minimize the total number of boilers in operation. The control sys-tem shall start and stop boilers when the water temperature is outside the adjustable tem-perature limit for longer than the adjustable time delay. In order to minimize temperature deviations, the control system shall start and stop the next boiler when the “lead” boiler is at an adjustable firing rate limit for longer than the adjustable time delay. The control sys-tem shall monitor both boiler lockout and limit circuits to automatically skip over those boilers that are powered down for maintenance, tripped or otherwise will not start. The boiler shall be run at low fire for warm-up for a preset low fire hold time. When enabled, warm weather shut down control logic shall prevent boiler operation. The controller shall also be capable of auto-rotation of the boilers based on user-selected run time hours.

HOT WATER CONDENSING BOILERS 23 52 16- 5

5. A touch screen message display shall be provided to display numeric data, startup and shutdown sequence status, alarm, system diagnostic, first-out messages and boiler histori-cal information. In the event of a fault condition, the display shall provide help screens to determine the cause of the problem and corrective actions. Historical information shall include graphical trends, lockout history, boiler & circulator cycle counts and run time hours

6. The controller shall be capable of sequencing the boiler, domestic hot water or system circulators. Simple parameter selections shall allow all three pumps to respond properly to various hydronic piping arrangements including either a boiler or primary piped indi-rect water heater. The controller shall perform circulator exercise to help prevent pump rotor seizing.

8. The controller shall incorporate its own peer-to-peer communications on each connected boiler (up to eight [8] units) by using standard RJ45 ethernet cables. The control system shall allow the connected boilers to exchange signals as required to provide coordinated fully modulating lead/lag functions. It shall not be required to wire individual control sig-nals between boilers. The boiler control system shall be capable of communicating with a BAS using RS485 Modbus. The boiler control system shall allow individual boiler limits, lockout, boiler and system temperatures and firing rate status to be readable and water setpoint, boiler firing rate, and start/stop command to be readable and writable. The boiler control system shall network with a communication gateway to connect with BACnet communication protocol.

B. Boiler Trim

1. Combination pressure-temperature gauge, 3-1/2 inch diameter.

2. Supply and return temperature sensors - shall be mounted on the supply and return connec-tions inside the boiler jacket. Each sensor shall be accessible through a removable access door on the left side of the boiler. The boiler control shall measure supply and return tem-peratures and notify the operator if the direction of flow is reversed.

a. The boiler control shall adjust to impending temperature changes in such a way to minimize fuel consumption and maximize efficiency. The control shall meas-ure temperatures and the rate of change in those temperatures and respond early, rather than waiting for temperatures to exceed limit control settings.

3. Outdoor air temperature sensor, if required, to automatically adjust the modulation rate setpoint on the boiler according to the outdoor temperature to optimize boiler operation and efficiency.

4. Flue gas temperature sensor shall be mounted in the flue vent connector to monitor flue gas temperatures and reduce the blower speed when flue gas temperatures exceed 184°F.

If the flue temperatures exceed 194°F, a forced boiler recycle results.

5. ASME Section IV safety relief valve sized to exceed the gross output of the boiler which shall be factory set to relieve pressure.

6. Water flow switch to prevent the burner operation during low water flow conditions.

7. Air vent valve shall be included to release trapped air inside the boiler’s heat exchanger.

8. Drain valve, 3/4 inch.

HOT WATER CONDENSING BOILERS 23 52 16- 6

9. Auxiliary safety high limit aqua-stat with manual reset.

10. High and low gas pressure switches with a range of 4.5 - 13.5 PSIG, wired to put the boiler into a hard lockout, requiring manual reset of the boiler primary safeguard control.

11. Low water cutoff (LWCO) device with manual reset. Boiler shall be fitted with a probe type LWCO located above the lowest safe permissible water level established by the boiler manufacturer. LWCO shall be UL listed and FM approved and suitable for com-mercial hydronic heating service at 80 PSI.

C. Vent & Intake Air Connections

1. The vent system shall be in accordance with National Fuel Code, NFPA 54/ANSI Z221.3 or CAN/CSA B149.1 Installation Code for Canada, or, applicable provisions of local build-ing codes.

2. The boiler shall be vented using PVC/CPVC vent material in accordance with local code.

A Factory supplied 90º elbow (schedule 80 CPVC) and a 30-inch length of schedule 40 CPVC pipe must be included as a transition from the boiler to traditional solid core sched-ule 40 PVC vent material.

3. Air intake piping shall be PVC that is sealed and pressure tight. Pipe must be at least the same size as the inlet air connection on the boiler.

2.3 PERFORMANCE

A. See “Equipment Schedule” shown in Project Drawings for additional information.

B. The burner shall emit no more than 20 ppm NOx and 50 ppm CO (corrected to 3% O2) at all firing rates.

C. Provide services of a manufacturer's authorized representative, Weber-Huff, Inc., to perform com-bustion test including boiler firing rate, gas flow rate, heat input, burner manifold gas pressure, percent carbon monoxide, percent oxygen, percent excess air, flue gas temperature at outlet, am-bient temperature, net stack temperature, percent stack loss, percent combustion efficiency, and heat output. Perform test at minimum, mid-range, and high fire.

PART 3 - EXECUTION

3.1 INSTALLATION

A. Install boiler(s) and associated components in accordance with Contract Documents and boiler manufacturer’s written installation instructions and recommendations.

B. Flush and clean the boiler upon completion of installation in accordance with manufacturer’s written start-up instructions and recommendations. The boiler shall be isolated when any cleaning or testing of the system piping is being performed.

C. Install boiler(s) plumb and level, within acceptable tolerances of the boiler manufacturer.

D. Maintain manufacturer’s recommended clearances around and over equipment, and as required by applicable codes.

HOT WATER CONDENSING BOILERS 23 52 16- 7

E. Arrange all electrical conduit, piping, exhaust vent, and air intake with clearances for burner removal and service of all equipment.

F. Connect exhaust vent to boiler vent connection.

G. Connect full sized air inlet to connector on boiler.

H. Connect fuel piping in accordance with NFPA 54. Pipe size to be the same or greater than the gas train inlet connection.

I. At a minimum, use full size pipe / tubing on all gas vent connections.

J. Connect water piping, full size, to supply and return connections.

K. Furnish and install all piping accessories as indicated in the Project Drawings.

L. Furnish and provide all electrical connections for properly functioning boiler unit(s) (electrical power, specified control interlocks with building control system, specified monitoring by building control system, etc).

M. Furnish and install discharge piping from relief valves and all drains to nearest floor drain.

3.2 START-UP, TESTING, AND TRAINING

A. Contractor shall engage manufacturer authorized / certified technician to perform start-up services and confirm proper operation, including control and monitoring by building control systems.

Demonstration to Owner of properly operating boiler units shall be provided. Additionally, a minimum of four (4) hours of “on-site” training on operating and maintenance instructions shall be provided to the Owner by the authorized technician.

3.3 WATER TREATMENT

A. Exact level of glycol in the hot water heating piping system is not known, Contractor shall assume some level of glycol is present. Any draining of the piping system for the specified boiler and piping system replacement shall include all means and methods to capture and legally dispose of the fluid.

B. Prior to any demolition work, Contractor shall sample and test for existing glycol levels and to determine the “per cent” level of glycol in the system. Contractor shall submit test results to Owner for review.

C. Contractor shall furnish and provide new glycol into the renovated hot water heating piping system. New glycol shall be inhibited propylene type. The amount of new glycol to be added to the hot water heating system shall be coordinated with Owner prior to installing. For proposal purposes, Contractor shall provide nominal 100 gallons of glycol. Contractor shall provide all hoses, pumping equipment, and connection(s) to add the glycol and shall employ means and methods to add glycol in an efficient manner while limiting waste.

END OF SECTION 235216