Answers to RFIs for 2nd Site Visit.pdf
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- Solicitation number
- 36C25726R0058
About this file
This document is a Responses to Request for Information (RFI) for Project Number 549A4-26-405, Replace Heat Exchanger Bonham, under Solicitation 36C25726R0058. The RFI addresses three primary questions regarding the heat exchanger replacement project affecting buildings #1, #2, and #29.
The first question concerns compliance with VHA Directive 1810(1) regarding cast iron fittings and valve housing materials in steam distribution systems operating at 15 psig or above. The government clarified that steam pressure reducing valves can be adjusted to supply steam below the 15 psig threshold, exempting the installation from the directive requirements. Thermal calculations must use steam pressure values below this threshold. Any work on upstream steam supply piping must comply with the directive. Regarding manufacturer-provided package components such as domestic water heater steam control valves that may not meet material construction requirements, the government deferred to the primary answer, indicating no exceptions are anticipated. The second question addresses integration with the existing Siemens Building Automation System (BAS). The government confirmed that new heat exchangers must include new detectors to connect to BAS automation systems and that proposals should integrate all feasible monitoring parameters, including valve status, hot inlet temperature, cold inlet temperature, valve outlet temperature, ERR temperature, and set point temperature. Graphics for these monitoring functions already exist within the Siemens BAS system and do not require creation.
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Answers to RFI's for Project Number 549A4-26-405 Replace Heat Exchanger Bonham
Solicitation 36C25726R0058
1. Specifications for units located in building #1, #2, and #29 indicate that the steam supply pressure is 15-psig. In accordance with VHA Directive 1810(1) - Operational Alert and Guidance Document FY2022-01, Cast Iron Fittings / Valve Housing Use In High and Medium Pressure Steam Distribution Systems, December 14, 2022 - “New construction, renovation, repair, replacement, or any other projects shall not use cast iron fittings, and components or malleable/ductile fittings anywhere in the high-pressure and medium pressure steam system (15 psi or above). All new construction must use only cast steel or forged steel fittings and components, in accordance with applicable VA Master Specifications”. Does this apply to the required steam work in buildings #1, #2 and #29?
ANSWER: The steam pressure reducing valves in all buildings can be adjusted to supply steam at a pressure below the 15 PSIG threshold, keeping the installation exempt from the above referenced directive. Thermal calculations for BTU or pound per hour steam requirements should be made with a steam pressure value that is below the 15 PSIG threshold. Any work performed on steam supply piping, that may occur upstream of the pressure reducing valves, must comply with the directive
a. If this directive must be followed will there be an exception allowed for the domestic water heater’s steam control valve, and any other manufacturer provide package components, that may not meet the materials of construction requirements? We have looked at several different packages from different manufacturers and haven’t found any that offer the steam control valve in cast or forged steel.
ANSWER: See answer to question 1
2. Based on previous RFI responses, it appears these new units need to be tied into the Siemens BAS system. It is our understanding that the existing units are not tied into the BAS. Is this correct?
ANSWER: Each of these buildings has an independent provision to monitor heat exchanger supply temperature to the building. This is visible within the Siemens BAS but not directly connected to the heat exchanger. All new heat exchangers being installed should include all new detectors to connect to BAS automation systems.
a. If so, what feedback is required? We assume water outlet temperature and unit status (on/off).
ANSWER: Refer to question 2B
b. Will graphics for these items need to be created, or do they already exist in the Siemens BAS system?
ANSWER: Graphics do exist and include the following monitoring and functionality options that are available in the existing system.
1. Valve status
2. Hot inlet temp
3. Cold inlet temp
4. Valve out temp
5. ERR temp
6. Set point temp
c. Are there any additional Siemens control/feedback requirements for the new water heaters that we need to include?
ANSWER: Proposals should include Integration of all feasible monitoring parameters listed in RFI 2.b.
File details come from the government source that posted it. Updated .