LSI 099-77SW .pdf

1 of 5 ITEM NO: 099-77SW

FY20

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SWRMC

LOCAL STANDARD ITEM

FY-2020

ITEM NO: 099-77SW

DATE: 21 AUG 2019

CATEGORY: II

1. SCOPE:

1.1 Title: Single Barrier to the Sea and Cofferdam Installation; accomplish

2. REFERENCES:

2.1 S0600-AA-PRO-160/CH-16, Underwater Ship Husbandry Manual, Cofferdams

2.2 S0400-AD-URM/TUM, Tag-out User’s Manual

2.3 845-4612172, Hydrostatic Test Blanks

2.4 805-7370421, NNSY Hull Type Cofferdam Standard Drawing

3. REQUIREMENTS:

3.1 Maintain watertight integrity to a level 4 feet above the maximum calculated draft, including the following operations: access openings, hull plating replacement, welding to the hull when pre-heating is required, modifications or repairs to damage or deterioration that will degrade watertight integrity or stability, or piping and mechanical repairs that are expected to result in less than double-valve protection.

3.2 Provide a representative, whose purpose is to coordinate the single barrier to sea requirements, and/or Government installed cofferdams with contractor’s work in accordance with 2.1. (See Notes 4.3 and 4.4.) The representative will:

3.2.1 Meet with the Commanding Officer's designated representative, Government Divers, and the SUPERVISOR as necessary to remove scheduling conflicts with ongoing operations, ship’s systems, and government diver operations (See Notes 4.5 and 4.6).

3.2.2 Notify Government Divers at least 5 working days prior to the need for cofferdam installation and 48 hours prior to a need for diver support services (See Note 4.7).

3.2.3 Conduct a joint safety brief ensuring all cognizant personnel have direct knowledge of the requirements prior to work requiring coordination between the Contractor, Subcontractors (if any), Government Divers, and/or

Ship's Force.

3.2.3.1 A Muster Sheet will be filled out and provided to the

SUPERVISOR indicating the names, position, e-mail address, phone number, and Signature for each attendee.

3.3 A Work Authorization Form (WAF), separate from the divers safety WAF, must be used to control the installation, the work protected by, and the removal of the cofferdam (See Note 4.9).

3.3.1 The Repair Activity responsible for the work must complete block 9 of the WAF. Block 9 should read, “COFFERDAM REQUIRED FOR PROTECTION FROM

SEA” OR “COFFERDAM REQUIRED, COMMANDING OFFICERS PERMISSION REQUIRED FOR

SINGLE BARRIER PROTECTION FROM SEA, See continuation sheet.”

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3.3.2 Attachment A WAF continuation sheet must be attached to the WAF prior to submission to ship’s Watch/Duty Officer for processing blocks 11 through 14.

3.4 Submit written notification to the SUPERVISOR at least 24 hours, but no more than 36 hours, prior to the start of work, and/or cofferdam installation.

Include in the written notification a specific plan for immediate installation of a replacement piping component or internal sealing blank to restore double-barrier to sea, as required by Paragraph 16-4.7.1.5, 16-5.2.10, or 16-7.6.5 of

2.1.

3.5 Government Divers must be at the work site to establish and maintain watertight integrity of the cofferdam during any period of time the cofferdam acts as a single barrier to sea. Exceptions to this requirement may be granted by the Ship’s Commanding Officer in writing in accordance with 2.1. (See Note

4.8)

3.5.1 Single barrier to sea evolutions with divers on station, as required by Paragraphs 16-4.7.1.10, 16-5.2.21, 16-6.6.11 and 16-7.6.9 of 2.1, outside of 0700 to 1500 weekdays, must be requested by the Contractor in writing, and approved by the SUPERVISOR. Repairs requiring extensions require continuous around the clock work until complete while in a single barrier condition.

3.6 Cofferdam Required for double barrier and brief period single barrier to sea:

3.6.1 If a sea chest closure valve is being worked or cannot be secured, a government diver installed Cofferdam, in combination with an internal sealing blank or equivalent, must be installed immediately after the affected component is removed in order to meet the double barrier protection requirement.

3.6.1.1 Authorization of single barrier protection during the brief period occurring between the time the repair component is removed and the internal sealing blank is installed and between the time the internal sealing blank is removed and the affected component is installed, is at the discretion of the ships Commanding Officer, in accordance with 2.1 and 2.2.

3.6.1.2 If no other internal vent exists, the internal sealing blank will have a vent valve installed, which is less than ½ inch in diameter.

3.6.1.3 Internal blanks must conform with 2.3. Gaskets must conform to

MIL-PRF-1149 (latest revision). Fasteners must conform to MIL-DTL-

1222J.

(V) "LEAK CHECK"

3.6.2 Conduct a joint watertight integrity inspection with Government

Divers, prior to each use of single barrier protection, in accordance with

2.1.

3.6.2.1 Ship’s Commanding Officer permission must be obtained for each single barrier protection occurrence.

3.6.2.2 Verify uninterrupted two-way communications between the

Government Divers and the Contractor at the work site.

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3.6.2.3 Verify water tight integrity of the cofferdam being used as a single barrier. Allowable leakage: In accordance with 2.1.

3.6.3 Where possible, a constant vent or drain path will be opened between the two pressure barriers, to warn if the upstream pressure barrier is leaking. (See 16-5.2.18.1, 16-7.7.2 and Appendix-G of 2.1.)

3.7 Cofferdam required as single barrier to sea:

3.7.1 Authorization of single barrier protection is at the discretion of the ships Commanding Officer, in accordance with 2.1 and 2.2.

(V)(G) "VERIFY PREVENTIVE MEASURES"

3.7.2 Prior to initiating a single barrier to sea condition utilizing a cofferdam, conduct joint inspection with Government Divers, and the

SUPERVISOR to verify:

3.7.2.1 Emergency dewatering equipment is at the work site, in accordance with the ships emergency flooding plan and 2.1.

3.7.2.2 Verify uninterrupted two-way communications between the

Government Divers and the Contractor at the work site.

3.7.2.3 Verify divers are on station, and will remain, until double barrier protection is established, in accordance with 2.2, repairs are completed, or ship’s Commanding Officer or his designated representative’s permission is granted to release the divers in writing, in accordance with 2.1.

(V)(G) "LEAK TEST"

3.7.3 Conduct a joint watertight integrity inspection with Government

Divers prior to each use of single barrier protection, in accordance with

2.1.

3.7.3.1 Verify integrity of the cofferdam used as a single barrier for water tightness. Allowable leakage: In accordance with 2.1.

3.8 No cofferdam required, i.e. temporary single boundary to sea:

3.8.1 Immediate installation of an internal sealing blank in combination with a closed sea chest valve meets the double-valve protection requirement without a diver installed cofferdam, provided the ship's Commanding Officer or his designated representative has been notified, in accordance with

Appendix G of 2.1.

3.8.1.1 Repair personnel will install a replacement component or an internal sealing blank with a gasket, in accordance with 2.2 and 2.3, immediately after the affected component is removed.

3.8.1.2 Internal blanks must conform with 2.3. Gaskets must conform to

MIL-PRF-1149 (latest revision). Fasteners must conform to MIL-DTL-

1222J.

3.8.1.3 Authorization of single barrier protection during the brief period occurring between the time the repair component is removed and the internal sealing blank is installed and between the time the internal sealing blank is removed and the affected component is installed, is at the discretion of the ships Commanding Officer, in accordance with 2.1 and 2.2.

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(V) "LEAK CHECK"

3.8.2 Prior to each use of single barrier protection verify:

3.8.2.1 Ship’s Commanding Officer permission is obtained for each single barrier protection installed.

3.8.2.2 The integrity of the valve used as a single barrier to sea.

Allowable leakage: In accordance with 2.1.

(V) “COFFEDAM REMOVAL LEAK CHECK”

3.9 Conduct a joint watertight integrity inspection with Government Divers as controlled flooding of the affected system is conducted by divers.

3.9.1 Verify uninterrupted two-way communications between the Government

Divers and the Contractor at the work site.

3.9.1 Check all disturbed joints for leakage. Allowable leakage: None.

4. NOTES:

4.1 2.1 and associated forms are available at:

http://www.navsea.navy.mil/Portals/103/Documents/SUPSALV/UWSH/chap16.pdf https://secure.supsalv.org/00C5publications.asp

4.2 Maximum Calculated Draft (MCD) – The maximum draft, calculated during the period in which ship’s draft is affected due to evolutions which add, remove, or change weight. It represents the “worst case” cumulative effect at any one time on trim, list, or draft for the proposed weight changes throughout the period that hull penetrations are in a non-standard configuration. MCD must be known and utilized by the SUPERVISOR and Ship’s Force in scheduling work and testing during waterborne maintenance periods.

4.3 Cofferdams are defined as: any plug, patch, or dry chamber installed externally to the hull of a ship at or below the waterline in order to secure or dewater an area or system to enable shipboard personnel, to conduct maintenance or repairs to the hull or system. They can be as simple as a wooden plug inserted into a round opening or as complex as a dry chamber for a shaft coating repair. NNSY Standard Cofferdams, identified in 2.4, allow Government Divers to blank most existing Fleet hull openings without additional engineering support.

(Paragraph 16.9.1.1 of 2.1.)

4.4 Minimum government responsibilities for cofferdam installation can be found in Appendix D of 2.1.

4.5 In order to ensure that cofferdam operations are effective, coordination between the Contractor, Subcontractors (if any), Government Divers, and Ship's

Force is paramount. The responsibility of cofferdam design, selection, fabrication, installation, and removal is under the purview of the Government

Divers. Although the Prime Contractor is charged with adherence to this standard, it does not abrogate the Commanding Officer's/Master's responsibility for the safety of the ship.

4.6 The term “SUPERVISOR” is defined as the local Government activity responsible for the execution, and contract administration of Navy maintenance and modernization work.

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4.7 Southwest Regional Maintenance Center’s divers contact information: Divers

Scheduling (619) 556-6535, Duty Diving Officer (619) 381-6632, Petty Officer of the Watch (619) 556-7130/6535.

4.8 This Local Standard Item does not imply authorization of single valve protection. Single valve authorization can only be made by the ship’s Commanding

Officer, case by case, based on specific conditions at the time of execution.

The Contractor should consider all jobs to require double valve protection when submitting proposals.

4.9 The diver’s WAF is for diver’s safety alone and may not be used for the authorization or control of Contractor work.

4.10 The primary purpose of this document is to provide coordination, notification, work authorization, and blanking requirements for work requiring single barrier from sea supported by Government Divers and government installed cofferdams.

4.11 This document requires the coordination of practices between Contractor, Subcontractors (if any), Government Divers and Ship's Force to ensure consistently safe operations in the common requirements of 3.6 through 3.8 and

3.9. Each of the conditions as defined in 3.6, 3.7, and 3.8 has its own unique additional procedural controls.