Section 10-1: Electrical Design Considerations
10-1-00 Design Requirements
10 Design Guidance
20 Design Information
30 Design Document Requirements
10-1-00 Design Requirements
The following design requirements apply to all electrical systems. The goals and objectives are to provide uniformity of design; combine the best overall economy with suitability of design; and be compatible with all other building systems. Provision shall be made for the addition of future electrical loads as determined by the NIH on a project-by-project basis.
10-1-10 Design Guidance
Where the electrical design is of an unusual nature and the intent is not readily discernible, the basis of design and/or design analysis narrative shall be prepared to explain the intent and reasoning behind the innovative design. This shall be presented in the earliest stage of review to ensure that the design is suitable.
10-1-20 Design Information
A. Reference Design and Safety Guidelines for the Electrical Designer:
The NIH is a progressive and dynamic biomedical research institution where state-of-the-art medical research is the standard practice. To support state-of-the-art research and medical care, the facilities must also be state-of-the-art. It is NIH’s intent to build and maintain the electrical systems and facilities in accordance with the latest standards.
It has been the NIH experience that the renovation and rehabilitation of existing facilities do not always lend themselves to incorporating the "latest" standards of the industry. Some of the existing electrical systems are outdated or inadequate for the new load. Often the planned function is incompatible with the original criteria for the building.
The A/E should be alerted to this situation and make an evaluation early in the design stage to determine the implementation feasibility of the latest standards. The A/E should document such findings, provide recommendations, and report them to the Project Officer for a decision on how to proceed.
The A/E design firm should use and comply with, as a minimum, the latest issue of the following design and safety guidelines available at the time the project proceeds with schematic design. In addition, the A/E should use other safety guidelines received from the NIH Project Officer or as required by the program.
The reference codes, regulations, and recommended practices include but are not limited to the latest version of the following:
• Association of Edison Illuminating Companies (AEIC)
• American Hospital Association (AHA), Management and Compliance Series, Electrical Systems for Health Care Facilities
• American National Standards Institute (ANSI)
• AHA, Management and Compliance Series, Fire Warning and Safety Systems
• American Society of Mechanical Engineers (ASME) A17.1: Safety Code for Elevators and Escalators
• Electronic Industries Alliance (EIA)
• International Building Code (IBC), International Code Council, Inc.
• International Cable Engineers Association (ICEA)
• International Electro-technical Commission (IEC)
• Institute of Electrical and Electronics Engineers (IEEE), Color Books
• Illuminating Engineering Society of North America (IESNA), Lighting Handbook
• Lightning Protection Institute, LPI 175 Standard of Practice
• National Electrical Code (NEC), National Fire Protection Association NFPA Standard 70
• National Electrical Manufacturers Association (NEMA)
• National Electrical Safety Code (NESC) IEEE C2
• International Electrical Testing Association (NETA), Acceptance Testing Specifications for Electric Power Distribution Equipment and Systems
• NFPA, National Fire Codes (NFC)
• NIH, Design Requirements Manual
• Institute of Laboratory Animal Resources (ILAR), The Guide for the Care and Use of Laboratory Animals
• Telecommunications Industries Association (TIA)
• Uniform Federal Accessibility Standards (UFAS)
• Underwriters Laboratories (UL)
10-1-30 Design Document Requirements
See Appendix B for detailed requirements of submittals at each phase of the project.
A. Electrical (Schematic, Design Development and Contract Documents)
Lighting and Power floor plans, one line diagrams, fixture, panel and equipment schedules, miscellaneous details, and cover sheet requirements.
B. Specifications (Outline and Detailed Performance Specifications)
Outline specifications shall be developed at the design development stage and detail performance specifications shall be developed at the contract document stage.
C. Cost Estimates (Systems and Quantity Takeoff Estimates)
Systems cost estimates shall be developed at design development stage and quantity take-off estimates shall be developed at the contract document stage.
D. Calculations and Analyses:
Each electrical design shall include the submittal of the following design calculations and analyses:
• Lighting calculations providing illumination levels in lux. Point by Point calculations shall be provided for areas with unique lighting arrangements.
• Estimated connected and demand distribution equipment loading, including an additional 25% for future building loads.
• Electrical service sizing based on the NEC and the DRM.
• Panelboard loads summation for justification of distribution equipment sizing.
• Economic analysis for justification of selection of either 120/208 V or 277/480 V on the secondary side of the network distribution transformers.
• Analysis to determine, if large central or smaller 120/208 V step-down transformers are to be used. An economic analysis shall be performed if the choice is not obvious.
• Transformers, Uninterruptible Power Supply (UPS) and Generator sizing calculations.
• Voltage drop calculations for branch circuits longer than 20 m (65 ft.) at 120V and branch circuits and feeders longer than 45.7 m (150 ft.) at 277V or higher.
• Initial short circuit analysis determining the interrupting or withstand rating of the system components and justification for selection of distribution equipment. Final short circuit analysis shall be performed by the distribution equipment manufacturer based on the actual distribution equipment proposed for installation.
• Coordination study determining the circuit breaker settings and system coordination. Final coordination study shall be provided by the distribution equipment manufacturer.
The A/E shall provide hard copy reports and all electronic files associated with the power system study showing corresponding bus and cable run identification numbers corresponding to the calculations; system load calculations for switchgears, switchboards, motor control centers (MCCs), panelboards, busways, risers, and transformers; and product and photometric data sheets for all fixtures specified in the design.
The power system study shall be performed using NIH approved software and shall be submitted to the Project Officer prior to receiving final approval of the distribution equipment shop drawings and/or prior to release of equipment for manufacturing. If formal completion of the study would cause delay in equipment manufacturing, approval from the Project Officer may be obtained for a preliminary submittal of sufficient study data to ensure that the selection of device ratings and characteristics will be satisfactory.
The study shall include executive summary, assumptions; short circuit study results, load flow study results, motor starting study results, protective device coordination results, feeder voltage drop calculations, arc flash analysis and conclusions. The study shall include all portions of the electrical distribution system from all power source(s) including the smallest adjustable trip circuit breaker in the distribution system. System connections that result in maximum fault conditions shall be adequately covered in the study.
The study shall be performed, stamped, and signed by a registered professional engineer, with a minimum of five years of experience in power system analysis. Credentials of the firm/individuals shall be submitted to the Project Officer for approval prior to start of the work.
E. Panel Schedules:
Panel schedules shall be completed on construction drawings, including all data required to order the equipment and to identify the attached loads. Information shown shall include:
• Panel name.
• Number and size of all breakers, including spares.
• Number of bussed spaces and the maximum ampere frame ratings.
• Total number of breaker positions in the panel.
• Bussing ampacity.
• Main circuit breaker (MCB) and rating or main lugs only (MLO).
• Surface or recessed mounting.
• Top or Bottom Feed.
• Installed location of panel.
• Trip rating, frame rating, and number of poles of each breaker.
• Short circuit interrupting rating of the panel; series rating not acceptable.
• Identification of the load and room number.
• Estimated connected load in volt-amperes (or kVa) per circuit (in watts or kW for generator loads).
• Panel total connected kVa and amperes (in watts or kW for generator loads).
• Panel total demand kVa and amperes (in watts or kW for generator loads).
F. Testing and Operational Requirements:
The A/E shall incorporate the following in the project specifications:
• Testing and operational training requirements.
• Startup and checkout of building systems.
• Operation and maintenance (O&M) manuals for all electrical equipment supplied on the project, in both hard copy and electronic formats on a CD-ROM, DVD, etc. Scanned items are acceptable.
G. Lighting Schedule
A lighting fixture schedule on drawings, identifying at least three manufacturers, catalog numbers, fixture voltage, lamp types, number of lamps, fixture depths, installation methods, description of fixtures, and remarks shall be provided for each fixture type identified as approved equals