Questions and Answers 2 - N6426724R0017.pdf

N6426724R0017 NAVAIR VSC IDIQ Questions and Answers 2

1. Q 1.

Government’s response to our previous questions states the following:

“… Based on the performance required for the most severe conditions and tolerances of that specification

(SAE AMS 2769), request that prospective contractor propose the chamber volume, “zero” pressure, and

“base” pressure required to meet that specifications….”

a) We have determined System’s operation parameters and configuration based on the Specification requirements. We are concerned about proposed Limitations to system dimensions 12 x 26 x 20 as stated in 3.4.1. The other factor to consider is the requirement of ISO 3467 – “Vacuum gauges —

Calibration by direct comparison with a reference gauge”. This important standard lays down the requirements for vacuum calibration systems design. One of the requirements is as follows:

“The calibration chamber shall have a volume of at least 20 times the total volume of all the gauges and associated pipe work connecting the chamber and the gauges (e.g. elbows shall be considered as part of the gauge volume).”

ISO 3467 is not referenced in paragraph 2.1 of the Specification.

Please confirm that the system design does not have to comply with ISO 3467 requirements.

A.1.a)

ISO 3467 was not used in the preparation of this specification. If it is determined that the specification cannot be met within the specified system dimensions, please make a recommendation through the

Contracting Office. If the content of the recommendation is technical in nature, it will be passed to a technical POC to be addressed.

b) SAE AMS 2769, Table I specifies Recommended Vacuum Range of 1x10-5 to 1x10-4 Torr for

Refractory Metals and 1x10-5 to 1 Torr for Titanium alloys.

If 1x10-5 is counted as “severe condition” as noted in Government’s response, then the low pressure measurement range of 1x10-4 Torr as called out in the Specification will not be adequate.

Please clarify.

A.1.b)

The vacuum furnaces at FRCSE are used for steels. The current revision (2769D) does not reference

Refractory Metals, but the Titanium and Titanium Alloys is there. Neither of those references apply to the use of the vacuum furnace at FRCSE.

2. Q 2.

We interpret statement in Government’s response regarding pressure control resolution as follows:

a) Vacuum Standards resolution should be at least 10 times (1 decade) better than the lowest required calibration pressure set point.

A.2.a)

Confirmed.

b) The Pressure control accuracy, as a percentage of deviation from the required calibration set point, will be determined by the accuracy and resolution of a Vacuum Standard at the required calibration set point.

Please confirm

A.2.b)

The intent of the purchased system is to provide the NIST-traceable calibration to the master units that will be used on the three-month interval to calibrate the vacuum ovens by comparison. If this statement meets that requirement, then it is confirmed.