J.3.3.2_Design Intent Report Cover_AMD003.pdf

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Juba, South Sudan U.S. Embassy Design Intent Document

Date:

July 13, 2020

ISSUED FOR BID

REVISED: September 27, 2021 Contract Number:

20AQMM20xxx

Prepared For:

U.S. Agency for International Development Juba, South Sudan

JUBA EMBASSY – DESIGN INTENT REPORT

JULY 13, 2020 ISSUED FOR BID

SEPT 27 2021 ADDENDIUM 1

Mason & Hanger Page 1

TABLE OF CONTENTS

0 GENERAL

Background

Path Forward

1 ELECTRICAL

General

Compound Generation, Loadbank and Distribution

Remote Monitoring and Alarm System

Residential Compound Safe Haven Transfer Switches

TOC Generator, Automatic Transfer Switch and UPS

Various Remedial Deficiencies on both Compounds

Additional Spare Parts Inventory

1.1 ASSUMPTIONS: Codes

1.2 RISK: Special Approvals, Environmental Conditions

1.3 O&M STRATEGIES: Equipment, Corrosion Resistance

2 MECHANICAL AND PLUMBING

General

2.1 ASSUMPTIONS: Codes

Design Criteria

2.2 RISK: Special Approvals, Environmental Conditions

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0 GENERAL

Background

In the aftermath of recent unexpected outages, Mason and Hanger was commissioned to perform an Electrical Distribution Study of the U.S. Embassy in Juba, South Sudan’s Office and Residential Compounds. The scope of the study is to perform an assessment and determine current weaknesses, vulnerabilities, and possible upgrades that can improve the reliability of both compounds. Special attention was given to the improvements of the prime rated generators and their configuration.

The facility staff has recognized that the electrical generation and distribution system is its lifeline for continued operation, resulting in higher availability expectations. Exemplary of this is the addition of automatic transfer switches intended to improve resiliency. As an unintended consequence, their addition has also revealed the limitations of the facility staff to implement, maintain and operate more sophisticated equipment within the current system.

Acknowledged are plans to either replace the existing Embassy or significantly renovate the Office Compound. With that in mind, operation of the facilities over ten years has been used for the purposes of recommendations. Should recommendations introduced herein be implemented, some subsequent renovations may be reduced, deferred or avoided in their entirety. Adopting similar operational philosophies will place less strain on the management team through those transitions.

Path Forward

Many of the recommendations included in the Electrical Distribution Study were selected and advanced as a part of this work, culminating in the development of a Request For Proposal using a Design-Build project delivery mechanism.

1 ELECTRICAL

The project replaces the Compound-wide electrical generation and distribution system on the Office Compound and the Residential Compound. Additionally, it adds a remote monitoring and alarm system, loadbanks, automatic transfer switches, a local standby generator, UPS and remediates existing building code deficiencies to allow the facilities to operate through a 10 year planning horizon.

General

No existing utility source is present, requiring 24/7 operation of compound-wide generation plants. Each compound generation plant operates on a single generator at a time with the balance either being in a ‘ready to run’ state or down for routine maintenance. Design solutions shall be as simple as possible, robust, reliable, low maintenance, with minimized / interoperable and rapidly available spare parts for onsite inventories.

Compound Generation, Loadbank and Distribution

This project selects generators for each Compound based on current maximum demand loads plus a 20% growth criteria in an N+2 configuration at the Compound level with appropriate ratings for 24/7 operation.

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The basis of design, based on collected load information yields minimum sizes of (3) 400kW Caterpillar C15 prime rated generators for the Office Compound and (3) 1250kW Caterpillar C32 prime rated generators for the Residential Compound. Final sizing shall be based on the Contractor’s research and metering effort.

To maintain simplicity of the system, a Caterpillar EMCP4.4 onboard paralleling system and associated breaker control has been selected.

Carter Machinery Company, Inc. has differentiated itself within the industry by offering startup, demonstration, turnover and support services throughout the world in the most challenging of environments.

The project shall use this service to ensure local staff are fully trained and capable after the successful installation, startup and acceptance of the generation and control system. After project acceptance, Carter shall provide the services of a factory-trained technician for a minimum of (3) months. For further information about this program, contact Jason Crews at (757) 995-7546 or Jason_Crews@CarterMachinery.com.

A second fully-rated output breaker from each generator shall connect it to a loadbank switchboard and loadbank near the generator plant. The loadbank controller or its switchboard shall monitor the system and trip offline should the generator under loadbank testing be needed to serve the load. Near each Compound’s generation plant, a generator output distribution switchboard shall reside in prefabricated, lit, air-conditioned, structure / walk-in enclosure. This structure allows full testing of the system using factory-certified technicians alongside generators prior to arriving onsite. To allow for bus isolation under maintenance or fault conditions, the generator output distribution switchboard is configured with bus isolation breakers between each generator. Two output breakers leave the generator output distribution switchboard to serve a new loop / ring. Engineering calculations for capacities, protective device selection as well as closed-transitions fault current, coordination studies and arc flash studies shall be performed with all equipment properly rated based on the conclusion of the accepted studies.

This new loop shall be installed in a new concrete encased ductbank around each compound. The ductbank shall be composed of sufficient conduits for the necessary ampacity conductors, signal cabling for the remote monitoring and alarm system and at least (2) spare empty conduits of the same size. Along this ring, freestanding skin-tight, dual-main switchboards will collect both outputs in a daisy-chained fashion, again, allowing for loop segmentation. Dual-main switchboards shall collect both sources then combine into a main serving the distribution breakers. These switchboards shall also have metering and surge protective devices to better establish and protect loads. Meters and surge protective devices shall be connected to each compound’s monitoring and alarm system. Existing loads will be collected at these points and reconnected by way of radial feeders. Initial design identifies a minimum of (5) dual-main switchboards for the Office Compound and (7) dual-main switchboards for the Residential Compound. Each generator output breaker, generator output distribution switchboard isolation breaker, output breaker, main-main breaker, loadbank feeders and loop conductor shall be sized for the full output of one generator. This count includes a dual-main switchboard near each compound’s generator yard.

Remote Monitoring and Alarm System

A complete monitoring and alarm system shall be provided in the ductbank for the previously mentioned meter and surge protective device locations. As well, the system shall collect information from the generators, controllers, loadbank and fuel storage and distribution system. The system shall allow for autodialing and paging staff based on preconfigured events and alarms. The Contractor shall prepare for all points of interconnected devices to be distributed to the system and consult with the facility personnel for preferred alarm and graphical user interface minimum data points to be displayed. A system similar to Eaton’s Foreseer system is envisioned. The Contractor shall coordinate with the facility personnel for final location of interfaces, but shall assume at least (2) complete workstations on each Compound, with additional remote connection points available throughout. Assume (1) workstation shall occur at each

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Compound generator output switchboard enclosure and the other shall be in the TOC for the Residential Compound and Post One for the Office Compound.

Residential Compound Safe Haven Transfer Switches

Currently, each of the two (2) Residential Compound Safe Havens (Blue and Orange) use manual transfer switches to select either the Compound wide generation source or the local Safe Haven Generator. This manual transfer solution necessitates staff to operate, thereby reducing the overall effectiveness of the system. This project shall replace the manual transfer switch solution with an automatic transfer switch for each Safe Haven. Adequate time delays shall be implemented to allow transfer of upstream generators in the event of an unexpected failure. The existing generators and replacement ATSs shall be monitored from the Remote Monitoring and Alarm System.

TOC Generator, Automatic Transfer Switch and UPS

As a vital part of both facilities security system, the TOC requires an additional layer of local redundancy.

A local standby generator, transfer switch and UPS with bypass shall be provided to provide such. As with the load monitoring of each Compound, the TOC loads shall be monitored for appropriate selection of sizing. Generator, ATS, and UPS shall be monitored from the Remote Monitoring and Alarm System.

Compound Annex Feeder from Each Compound Loop

Both the Office and Residential Compounds have expanded to occupy additional adjacent property. These properties will also be upgraded as a part of this work. Meter, survey and size the required radial feeder to be extended underground to each Annex. For each Annex, provide a radial underground feeder with adequate size to serve the existing load plus spare capacity but not less than 225 amps, 3 phase, 4 wire.

Coordinate with the Contract Officer for the preferred location on each Annex to terminate the feeder and place the Annex distribution board.

Additional Spare Parts Inventory

Beyond those required for installation, the Contractor shall provide a spare parts inventory. Interoperability and the rapid availability of parts shall be an integral part of this project. Throughout the design and construction, solutions shall identify the quantities and types of products that are being proposed. The following are minimum criteria and should apply not only at each Compound but between them to allow for optimal inventories:

• Breakers of the same make, model, bus connections, frame and trip ratings (where possible).

Minimum 4 per Compound sized per loop output breakers.

• All EMCP4.4 and control components. Minimum (2) preprogrammed, ready to be installed per Compound.

• Meters and Remote Monitoring and Alarm components. Minimum (2) each per Compound.

• ATS components. Minimum (2) per Compound.

1.1 ASSUMPTIONS: Codes

Design will be based on the 2021 OBO Design Guide.

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1.2 RISK: Unforseen Conditions, Underground Utilities and Cost

The most significant risk for the project is proper coordination, detailed investigation and planning to allow for the construction of the loop feed while maintaining existing infrastructure. It is likely that many utilities will be uncovered that are not documented requiring vertical offsets in ductbanks. Hand digging should be expected.

1.3 O&M STRATEGIES: Equipment, Corrosion Resistance

This is a sandy and salty environment therefore NEMA 4x for outdoor enclosures will be required for all electrical equipment located outside.

2 MECHANICAL AND PLUMBING

General

The Juba electrical upgrade project consist of two compounds, the Office Compound and the Residential Compound. Each compound has its own standalone fuel system to provide fuel to each compound’s generators.

Currently the Office compound is comprised of (2) 20,000L underground holding tanks and (1) 34,100L above ground tank. One of the underground tanks is used for the fueling of the generators and the other underground tank is used for vehicles via vehicle dispensing pump. Currently the fuel system is manually operated with multiple valves and electric pumps to isolate and fill individual tanks as well as the generator tanks. The generator that is “running” has its tank filled twice a day, once in the morning and once in the evening. The fuel tank levels are measured each day by the generator operator and confirmed by a USAID employee. Fuel is also tested each day. Fuel oil piping is supply only, without a return line. There is no fuel port on the exterior of the perimeter wall and there are no fuel filling alarms or leak detection. Once a week, (2) fuel trucks deliver fuel by routing hoses through an opening at the bottom of the perimeter wall into an in-ground connection point that fills the underground tanks.

The fuel system for the RC is comprised of (3) 25,400L underground holding tanks and (2) 27,000L, (1) 18,000L, and (2) 1,000L above ground tanks. The fuel system is manually operated with multiple valves and electric pumps to isolate and fill individual tanks as well as the generator tanks. The generator that is “running” has its tank filled twice a day, once in the morning and once in the evening. The fuel tank levels are measured each day by the generator tech and confirmed by a USAID employee. The fuel is tested each day. There fuel oil distribution is supply piping only with no return lines. There is no fuel port on the exterior of the perimeter wall and there are no fuel filling alarms or leak detection. Once a week, (2) fuel trucks deliver fuel by routing hoses through an opening at the bottom of the perimeter wall and connect to an in-ground connection point that fills the underground tanks.

Compound automated fueling system upgrade

The design intent is to automate the fuel transfer of diesel from the underground storage tanks to each corresponding generator daytank. This automation system (via fuel oil pumps) will distribute fuel more accurately and help create a more stable generator plant. Also by pumping the fuel automatically, this will remove the human error factor as well as relieve maintenance staff from maintaining this system. In addition to fuel oil pumps the design shall provide leveling alarming and monitoring of the fueling system.

Fuel Polishing

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Filtration is another important item to ensure operational status of the generators. Strainers and fuel polishers would greatly improve the fuel quality being served to the generators.

2.1 ASSUMPTIONS: Codes

Design Criteria

Applicable Codes and Standards

• Design will be based on the 2020 OBO Design Guide.

Fuel Storage

Preliminary calculations based on 7 days of storage (as prescribed by 2020 OBO Design guide to accommodate all current fuel needs) will require one (1) 5,000 gallon tank for the Office Compound Generators and one (1) 10,000 gallon tank for the Residential Compound Generator. In addition,the existing one (1) 20,000 gallon tanks for the diesel vehicular fill station shall remain. Site currently has a sizable amount of fuel storage that exceeds required amount. The intent is to minimize the cost of demolition of exiting tanks and allow the facilities to operate through a 10 year planning horizon. After additional information, the design can be modified to remove some of the existing above and below grade storage tanks.

2.2 RISK: Special Approvals, Environmental Conditions

1. Quantity/Accessibility to skilled local labor who can perform maintenance on equipment and/or provide timely equipment repairs.