00 51 21.01 Vent Duct Cleaning.pdf

DRYDOCK

WORK ITEM 106 VENT DUCT CLEANING

PART 1 GENERAL

SCOPE: This item describes the requirement to clean various heating, ventilation, and air conditioning (HVAC) systems through out NOAA SHIP.

1.1 References

NOAA

HVAC Diagram Drawing, NOAA SHIP HVAC Diagram

1.2 Government-Furnished

1. None.

PART 2 DEFINITIONS

2.1 None.

PART 3 REQUIREMENTS

3.1 General Requirements

1. Accomplish all of the following requirements for the entire systems listed in Appendix A.

2. Remove all dirt and debris accumulated during the performance of this work from the ship daily. Clean areas worked in or traversed by workmen and equipment daily.

3. Replace insulation damaged or removed during performance of work.

4. Touch up all painted surfaces damaged during the performance of work using marine grade coatings matching the surrounding areas.

3.2 Schedule Work

1. Prior to starting work, provide a work plan and schedule for the Chief Engineer and COR.

Outline the location and methods of gaining access to ducts and components for cleaning, and the day and time specific sections of the HVAC system will be inoperable. As changes occur in the schedule, advise the Chief Engineer and COR.

2. Schedule all work to minimize disruption of the ships' HVAC systems. Work on only one system at a time. Restore all systems to full operation at the end of each work shift except only when work will continue immediately on another work shift.

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3.3 Remove Interferences

1. Remove all interferences necessary to complete the required work. An interference is any structure, equipment, piping, bulkhead sheathing, overhead sheathing, cable, insulation, or other part of the ship which interferes with access to the ducting or equipment being cleaned.

After the work has been completed, restore the removed interference(s) to a condition equal to existing.

2. Use existing access openings in ducts to the extent practical. Where necessary, cut new accesses in the ducts for cleaning or inspection purposes. Seal new access openings with new sheet metal covers, gaskets, and sheet metal screws (no rivets).

3.4 Clean Ducts

1. Clean ducts removing all grease, dirt, dust, lint, grit, debris, and other foreign particles by using a vacuum truck. Dry ice cleaning is also acceptable in conjunction with the vacuum truck or contractor furnished fan in lieu of a skipper. Do not use ships fans to clean systems. If dry ice blasting of system is utilized, ensure that debris is not blown throughout the space or adjacent spaces. For either method, augmentation by hand tools and degreasers may be required as necessary to clean the systems.

2. Using a high-vacuum truck capable of pulling a minimum of 12,000 cubic feet per minute (cfm) through a 10-inch diameter duct, pull a high-volume reverse air flow through each section of ducting. While the high-volume air is being pulled through the ducting, air blast the entire interior of the ducting with a "skipper" hose delivering compressed air at a minimum of 125 psig.

3. For ducts having a cross-sectional area less than 75 square inches, maintain a reverse air flow velocity not be less than 350 feet-per-second. This velocity is roughly equivalent to pulling 12,000 cfm of air through a 10-inch diameter duct.

4. For ducts having a cross-sectional area of 75 square inches and greater, maintain a reverse air flow velocity not be less than that which can be created by pulling 12,000 cfm of air through the duct

5. Take necessary precautions and steps to ensure that ducting and components are not collapsed or otherwise damaged due to the excess vacuum created when pulling the reverse air.

6. If required to obtain the required air flow in individual branch ducts, temporarily blank off the registers, terminals and other openings in other branch lines.

7. Portable units may be substituted for vacuum truck. The vacuum collection device requirements include:

a. Render all areas being cleaned under negative pressure, such that containment of debris and the protection of the indoor environment are assured.

b. Remove dislodged debris from the ducting system.

c. Ensure discharge of portable units exhausts outside the ship's structure. Equip all vacuum devices exhausting air outside the ship's structure with Particulate Collection

DOCUMENT 00 51 21.01 Page 2 including adequate filtration to contain debris removed from the HVAC system. Ensure such devices exhaust in a manner that will not allow contaminants to re-enter the ship or contaminate the ship's decks and structure. Release of debris outdoors cannot violate any outdoor environmental standards, codes or regulations.

8. Clean all fans, filters, screens, coils, diffusers, dampers, mixing boxes, preheaters, heaters and other components in the specified HVAC system using degreasers and brushes as needed to remove all grease, dirt, dust, lint, grit, debris, and other foreign particles.

9. Remove and replace all disposable filters with new ones equal to existing. Dispose of removed filters in accordance with applicable Federal, State and Local environmental laws and regulations.

3.5 Inspections

16. Provide an opportunity for the Chief Engineer and the COR to inspect and accept each system prior to reinstalling access openings or closing up the system.

17. Accomplish a final walk through of the specified systems with the Chief Engineer and COR to prove all access openings are properly sealed prior to re-installing sheathing or interferences.

18. Accomplish a final walk through of the specified systems with the Chief Engineer and COR to prove that all overheads and interferences are restored and that the effected spaces are clean.

PART 4 QUALITY ASSURANCE

1. Perform required inspections with the Chief Engineer and COR.

PART 5 NOTES

1. None.

PART 6 APPENDIX A

6.1 NOAA SHIP HVAC Systems

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