DESICCANT MACHINE QUESTIONS AND ANSWERS_UPDATED.pdf

P26-005 Desiccant Machine Q&A’s

1. For both the Vacuum Test and Pressure Test modes, the solicitation specifies 27.7 ±0.3 inches H₂O.

Please confirm whether this value is expressed in gauge (relative to ambient) or absolute terms for each mode.

Based on the current desiccant leak procedure, the 27.7 ±0.3 inches H₂O value should be treated as a gauge pressure relative to ambient, not absolute pressure.

2. For the Vacuum Test mode, please confirm the intended sign of the pressure — i.e., is 27.7 in H₂O a negative gauge pressure (vacuum below atmospheric) or positive gauge pressure?

For the Vacuum Test mode, the value is intended to be a negative gauge pressure, meaning approximately 27.7 inches H2) below atmospheric pressure.

3. For the Pressure Test mode, please confirm whether the 27.7 ±0.3 in H₂O value is the same magnitude as the vacuum test but applied as positive gauge pressure, or whether a different value was intended.

For the Pressure Test mode, the value is the same magnitude, but applied as positive gauge pressure, meaning approximately 27.7 inches H2O above atmospheric pressure.

4. Is this a pressurized desiccant dehumidification system or are we feeding the mentioned vacuum and pressure blowers with dry air?

Based on the existing fluid schematic, the unit is supplied with facility shop air specified as “Dry, 90 - 110 PSIG.” The schematic does not indicate an internal desiccant dryer or dehumidification system.

The unit relies on an external source of dry compressed air, which is then filtered, regulated, and used to perform the pressure and vacuum leak tests. That said, would it be possible to ask the vendor if an internal dryer/ moisture removal option can be included? This would help ensure the replacement unit received clean, dry air consistently.

5. What are the desired supply air conditions (Temperature-Fdb, Dew Point-Fdp)?

The available drawing specifies dry shop air at 90 – 110 PSIG, I have not identified a specified dew point or temperature requirement in the existing engineering documentation.

6. What is the desired airflow (SCFM) from the dehumidifier?

I have not located a specified SCFM requirement for the incoming air supply. The system regulates the incoming air internally to perform the required leak tests.

7. Will the dehumidifier be installed outdoors?

No. The replacement unit will be installed indoors in Building 214.

8. Do you have a layout drawing or spec for the existing dehumidifier that you could share?

Fluid schematic attached. However, I would not recommend using the existing 1987 design as the basis for the replacement unit, as the intent of this procurement is to modernize the equipment. The replacement system should be designed to meet the functional and performance requirement outline in the Statement of work while taking advantage of current technology, improved reliability, and maintainability rather than duplicating the legacy design.