Q A__2__P45F73.pdf

Q&A#2

Solicitation : HSCGC85-15-Q-P45F73

USCGC Marcus Hanna – Dockside Repairs

1) In items 2 and 3, the work item specifies to sweep, mechanically clean, and vacuum. In lieu of the sweep and mechanically clean, would dry ice cleaning be a suitable substitute?

ANSWER: Yes, dry ice blasting would be acceptable for cleaning the exhaust stack uptakes (items #2 and 3).

2) Work item 8 calls for disassemble, inspect, and preserve. I would assume that prior to preservation there will be a cleaning required. Dry ice can take care of all of that cleaning.

ANSWER: Yes, dry ice blasting would be acceptable; however, in view of the fact that dry ice will not create a new surface profile, the contractor must take surface profile readings, and submit a CFR - prior to coating application.

3) Work items 9, 10, and 14 all call for low pressure or high/ultra high pressure water wash as a surface preparation. Dry ice will perform the necessary cleaning as the surface prep pre-wash. The only thing it won’t provide is additional profile.

ANSWER:

a). The low pressure wash is required to remove surface contaminants, including soluble chlorides - and this cannot be accomplish solely by dry ice blasting.

However, after completion of low pressure wash, dry ice blasting may be used as a surface preparation method, to remove all existing coatings - but ONLY for Items 9 and 14.

b). For item #10 (Decks – Exterior (Buoy or Construction Deck), Preserve 100%), the surface preparation MUST be as follows: low-pressure wash, followed by abrasive-blasting to "Near-White", IAW SSPC-SP 10. There will not be a waiver for this item.

4) Work item 13 doesn’t specify any surface prep pre-wash, just the preservation. Would there be any surface prep pre-wash as in item 9 and 10?

ANSWER:

a). Ultra-high pressure wash is not required for Item #13, as surface preparation method; however, low pressure wash is required for surface contaminant removal.

b). This item is identical to Item #10. Surface preparation MUST be as follows:

low-pressure wash, followed by abrasive-blasting to "Near-White", IAW SSPC-SP 10.

There will not be a waiver for this item.

Two very important issues that this particular MUST be made aware of - as follows:

1. Low-pressure wash is required, to remove surface contaminants, including soluble salts, prior to surface preparation.

2. “Preserve/Preservation”, when used in context of painting, refers to surface preparation and paint/coating application.