Overview of Electrical Engineering
for School Design
Thomas Mason, PE
The purpose of this course is to demonstrate the principles of electrical design for a large public facility. A school was chosen for the vehicle because we all have experiences with schools; schools have almost all of the construction details shown by large and small commercial and institutional buildings and, the author has considerable recent experience performing electrical design for schools.
Electrical design for schools has the following components, which will be individually studied in detail:
- Controlling Codes. This is a new requirement. Up until about five years ago, you designed the new school following the form of the design for the previous school. Today, however, radical changes in requirements are implemented with each Code revision, especially the International Energy Conservation Code, International Green Construction Code, ASHRAE 90.1 and LEED. It is critical to know which Codes are controlling for the immediate design. (The Architect on the job is responsible for determining these conditions and communicating it to each design discipline.)
- Utility Services. The school needs power and the school needs data. If the Electric Utility has available capacity at the location, the task is performed by a series of phone calls. If the electric utility does not have available capacity, it will be necessary to start work on their end very early in the project. They need a lot of paperwork before they will undertake their design to make power available. And, depending on their workload, they may require construction with several month duration. Low-voltage utilities, commonly data and telephone, are typically easy for schools. The school has a network connecting the administrative offices and each building. Typically they have a very friendly arrangement with one of the low-voltage service providers. The Owner tells the Architect who tells the electrical designer. The existing power and communications poles will be shown on the site plan, by the project Civil engineering designer and the electrical designer routes conduits to these poles as first approximation. Later in the project, these electrical plans are shared with the Utilities for their approval.
- Electrical Power Design. Each task within electrical design is iterative. That is, the designer puts down his first ideas and starts fleshing out the details. The next day when he comes back to the job, he audits his previous work and makes changes - sometimes details and sometimes major changes in the basic scheme. For electrical power design, I start at the Utility because building details, such as HVAC are not known at this time. There are 480 volt cables in conduit, usually covered by concrete, coming from the Utility transformer to the Main Switchboard. (The Architect chooses the location and size for the Main Electrical Room.) I then show 480 volt power cables, in conduit, to power distribution panels. On a good day, the Architect has selected locations for the Floor Electric Rooms. If not, the designer must apply the “125-ft Rule” to determine required Electric Room locations and negotiate with the Architect for space near these locations. There will be a 480V power panel, a 480-120V transformer and a 120V receptacle panel in the Floor Electrical Room. I leave placement of lighting fixtures, receptacles and large HVAC Equipment until later in the project, since these are prone to change several times before the project goes out to Bid.
- Electrical Lighting and Lighting Controls. I mentioned waiting on the lighting design until later in the project. However, it is desirable to do a sample room early on. This shows the electrical designer’s ideas and lets the Architect agree or offer recommendations for improvement. (The Architect is the immediate Client to the electrical designer, so these recommendations carry considerable force. Architect are usually deeply interested in the public spaces and less so in the classrooms, offices and conference rooms.) The sample classroom will be 30' x 30', with a board wall, windows, entry door and teacher's desk. All classrooms (almost) are 30' x 30', with a board wall, windows, entry door and teacher's desk. The lighting controls will be determined by the Energy Codes which apply to this project. This is one of the reasons for the early sample room, to achieve agreement on the method to comply with the Codes.
- Fire Alarm. Surprisingly, fire alarm design is changing rapidly. That is not quite correct. Twenty year old designs are still acceptable, but a wide range of innovations are available for consideration. Some provide considerably more safety to the occupants. Some are so new that there are few existing installations. Surprisingly, the innovations can be less costly than legacy designs. There are two parts to fire alarm design - the scheme and the details of implementation. There is no advantage to delaying detailed fire alarm design, as the devices can be easily moved when walls and doors move as part of the Architectural revisions.
- Data, Communications and Security. On State-funded school construction projects there is a requirement to hire an RCDD (Registered Computer Data Designer) to perform these tasks. On locally-funded projects and Charter Schools, an RCDD is usually not involved. In almost all cases the electrical designer lays out the pathways for cables, the receptacle boxes for jacks and the power for data racks. If so chosen, the electrical designer provides a generator and uninterpretable power.
The quiz at the
end is designed to enhance your understanding of the course materials and increase
your confidence in applying the principles herein contained.
At the conclusion of this course, the student will:
- Understand the responsibilities of the Plans Review official in approving the Construction Documents;
- Understand the responsibilities of the Architect in preparing the Code Sheet;
- Understand the importance of the official start date for the project;
- Understand the electrical design restrictions contained in the State Building Code;
- Understand the relationship between the State Building Code and the International Building Code (ICC);
- Understand the motivation for differences between the State Building code and the ICC;
- Understand the significance of the International Energy Conservation Code;
- Understand the significance of the International Green Construction Code;
- Understand the significance of ASHRAE 90;1 and each revision;
- Understand the significance of COMCHECK and the key content;
- Understand the Electric Utility procedure for starting a service project;
- Understand the data requirements of the Electric Utility to start the project;
- Understand how to calculate Lighting Power Density (LPD);
- Have a feel for how easy it is to attain different LPD values;
- Build a comfort level with COMCHECK;
- Understand the rules for motion detectors;
- Understand the rules for daylight harvesting;
- Understand the operation of computerized wireless lighting controls;
- Understand the form and typical content of the State School Design Guide;
- Understand the requirements for the Civil drawing showing Electric Utility service;
- Understand the form and content of the One-Line Diagram;
- Understand Tiered surge protection;
- Understand use of an Electrical Feeder Schedule in power design;
- Understand the required components of the electrical service grounding scheme;
- Understand basic requirements for Life Safety equipment and Emergency Generator;
- Understand the content of a fire alarm Riser Diagram;
- Understand typical security access control components and wiring;
- Understand modern CCTV equipment and wiring; and
- Understand the use of fiber optic for remote CCTV cameras.
This course is intended for project manager, electrical engineers, engineers and architects who work with electrical engineers and for contractors.
Some students will want to verify every detail while others may be only interested that a topic is addressed by the designer and wish to gain a little insight into the controlling factors. Both groups’ needs should be well met by this course. The greater hazard in school design is entirely missing a requirement, more than in adopting a less accepted interpretation of a Code Section.
Benefit to Attendees
with experience in work on schools will recognize most steps, but may be a little
surprised by the constraints that the electrical engineer is working under.
Persons new to electrical design may be overwhelmed by the range of responsibilities
of the electrical engineer. The result should be that future school design jobs
will encounter fewer mis-communications and mis-steps.
course content is in Overview of
Electrical Engineering for School Design (a PDF File). You need to
open or download this document to study this course.
This course discussed the responsibilities of the electrical designer on a new school or school renovation project. Six areas received special focus - controlling codes, utility services, power distribution, lighting and lighting controls, fire alarm, data, communications and security.
technical information related to this subject, please visit the following websites
or web pages:
iccsafe.org - publisher of the IBC, IECC, IGCC and other Codes, except the NEC.
https://www.energycodes.gov/comcheck - US Department of Energy website for COMCHECK
https://www.energycodes.gov/status-state-energy-code-adoption - indicator map of Code adoption - warning, always out of date
www.legrand.us/wattstopper.aspx - vendor of lighting control products, long history of adoption
ofcc.ohio.gov/Resources/DesignManual(OSDM)/2017OSDM.aspx - source website for Ohio School Design Guide books (free)
https://www.arcomnet.com/masterspec/ - vendor for AIA / CSI “canned” specifications
NFPA.org - vendor for the National Electrical Code and many specialized building Codes
www.lutron.com/ - vendor of computerized wireless distributed (each room independent) lighting controls
https://standardscatalog.ul.com/standards/en/standard_924_10 - internet address for Underwriters Laboratories, testing and listing body and Standard 924, Life Safety lighting controls
Amazon.com - vendor of high-quality, low-cost commercial lighting and security equipment
https://www.bicsi.org/ - organization licensing RCDD, Registered Computer Data Designers
you finish studying the
above course content,
you need to
take a quiz
to obtain the PDH credits.
DISCLAIMER: The materials
contained in the online course are not intended as a representation or warranty
on the part of PDH Center or any other person/organization named herein. The materials
are for general information only. They are not a substitute for competent professional
advice. Application of this information to a specific project should be reviewed
by a registered architect and/or professional engineer/surveyor. Anyone making
use of the information set forth herein does so at their own risk and assumes
any and all resulting liability arising therefrom.