Author Archives: mike@standardsmichigan.com

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Rightsizing Electrical Power Systems

University of Michigan

 

Rightsizing Commercial Electrical Power Systems: Review of a New Exception in NEC Section 220.12

Michael A. AnthonyJames R. Harvey

University of Michigan, Ann Arbor

Thomas L. Harman

University of Houston, Clear Lake, Texas

For decades, application of National Electrical Code (NEC) rules for sizing services, feeders and branch circuits has resulted in unused capacity in almost all occupancy classes. US Department of Energy data compiled in 1999 indicates average load on building transformers between 10 and 25 percent. More recent data gathered by the educational facilities industry has verified this claim. Recognizing that aggressive energy codes are driving energy consumption lower, and that larger than necessary transformers create larger than necessary flash hazard, the 2014 NEC will provide an exception in Section 220.12 that will permit designers to reduce transformer kVA ratings and all related components of the power delivery system. This is a conservative, incremental step in the direction of reduced load density that is limited to lighting systems. More study of feeder and branch circuit loading is necessary to inform discussion about circuit design methods in future revisions of the NEC.

CLICK HERE for complete paper

University of Houston

2026 National Electrical Code Workspace

Fenestration

The oldest door still in use in Pantheon (115 A.D.)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

“No work of art can be great,

if it is not composed of the smallest things.”

Vitruvius  (Book VII, Chapter 9)

 

Today we sweep through standards action in building glazing, entrances and means of egress.  The word fenestration (Latin: fenestra) has become a term of art for the design, construction, and placement of openings in a building, including windows, doors, skylights, and other glazed elements.  While the word has sparse use in the International Code Council and National Fire Protection Association catalog it is widely used by the Construction Specifications Institute in its MasterFormat system for organizing construction standards, guidelines and building contracts.

The percentage of a building envelope “skin” that is comprised of doors and windows varies depending on the specific building design, function, and location. However, a commonly cited range is between 15% to 25% of the total building envelope.  The actual percentage will depend on several factors such as the building’s purpose, orientation, local climate, and energy performance goals. Buildings that require more natural light or ventilation, such as schools, hospitals, and offices, may have a higher percentage of windows and doors in their envelope. In contrast, buildings with lower lighting and ventilation requirements, such as warehouses, may have a smaller percentage of windows and doors.

Fenestration presents elevated risk to facility managers.  The education facility industry is a large target and a pattern of settling out of court.   For example:

  • In 2013, a former student at Yale University sued the school over a broken window in her dorm room. The student alleged that the university was negligent in failing to repair the window, which allowed a burglar to enter her room and sexually assault her. The case was settled out of court in 2015 for an undisclosed amount.
  • In 2019, a student at the University of California, Los Angeles sued the school over a broken window in her apartment. The student alleged that the university was negligent in failing to repair the window, which allowed a swarm of bees to enter her apartment and sting her. The case was settled out of court for $4.5 million.
  • In 2020, a group of students at Harvard University sued the school over its decision to require them to move out of their dorms due to the COVID-19 pandemic. The students alleged that the university breached its contract with them by failing to provide suitable alternative housing, including functioning windows and doors.  (The case is ongoing; best we can tell as of the date of this post).

These cases illustrate that colleges and universities can face legal action related to doors and windows, either due to alleged negligence in maintaining or repairing them, or due to issues related to student housing and accommodations.

Our inquiry breaks down into two modules at the moment:

Exterior facing fenestration

Interior window walls and doors

Join us online at the usual time.

door (n.)

University of Arkansas at Little Rock

Related:

Means of Egress

Life Safety Code

Rijksuniversiteit Groningen

Guide to Premises Security

Library of Alexandria

NFPA 730 Guide to Premise Security guide describes construction, protection, occupancy features, and practices intended to reduce security vulnerabilities to life and property.  Related document — NFPA 731 Standard for the Installation of Electronic Premises Security Systems covers the application, location, installation, performance, testing, and maintenance of electronic premises security systems and their components.

The original University of Michigan standards advocacy enterprise (see ABOUT) began following the evolution of NFPA 730 and NFPA 731 since the 2008 Edition.   That enterprise began a collaboration  with trade associations and subject matter experts from other universities (notably Georgetown University and Evergreen State University) to advocate user-interest concepts in the 2011 edition.    A summary of advocacy action is summarized in the links below:

in the appeared in a trade association journal Facilities Manager:

APPA Code Talkers Anthony Davis Facility Manager May June 2011

An online presentation by Michael C. Peele (Georgetown University) — one of the voting members of NFPA 730 and NFPA 731 technical committees– was recorded and is linked below.

FREE ACCESS: 2023 Guide for Premises Security

FREE ACCESS: 2018 NFPA 730 Guide to Premise Security

Public comment on the First Draft of the 2026 Edition will be received until January 3, 2025.  You may key in your own ideas by clicking in to our user-interest Public Consultation Meeting Point or by communicating directly with the NFPA.

This title remains on the standing agenda of our Security colloquia.  See our CALENDAR for the next online meeting; open to everyone.

Design Standard Readability

Fry readability formula

How Consistent Are the Best-Known Readability Equations in Estimating the Readability of Design Standards?

Shixiang Zhou & Heejin Jeong
Industrial and Operations Engineering Department, University of Michigan, Ann Arbor, MI, USA
Transportation Research Institute Driver Interface Group
Department of Industrial and Operations Engineering, University of Michigan, Ann Arbor, MI, USA

 

Abstract.  Research problem: Readability equations are widely used to compute how well readers will be able to understand written materials. Those equations were usually developed for nontechnical materials, namely, textbooks for elementary, middle, and high schools. This study examines to what extent computerized readability predictions are consistent for highly technical material – selected Society of Automotive Engineers (SAE) and International Standards Organization (ISO) Recommended Practices and Standards relating to driver interfaces. Literature review: A review of original sources of readability equations revealed a lack of specific criteria in counting various punctuation and text elements, leading to inconsistent readability scores. Few studies on the reliability of readability equations have identified this problem, and even fewer have systematically investigated the extent of the problem and the reasons why it occurs.  Research questions:

(1) Do the most commonly used equations give identical readability scores?
(2) How do the scores for each readability equation vary with readability tools?
(3) If there are differences between readability tools, why do they occur?
(4) How does the score vary with the length of passage examined?

Method: Passages of varying lengths from 12 selected SAE and ISO Recommended Practices and Standards were examined using five readability equations (Flesch-Kincaid Grade Level, Gunning Fog Index, SMOG Index, Coleman-Liau Index, and Automated Readability Index) implemented five ways (four online readability tools and Microsoft Word 2013 for Windows). In addition, short test passages of text were used to understand how different readability tools counted text elements, such as words and sentences. Results and conclusions: The mean readability scores of the passages from those 12 SAE and ISO Recommended Practices and Standards ranged from the 10th grade reading level to about 15th. The mean grade reading levels computed across the websites were: Flesch-Kincaid 12.8, Gunning Fog 15.1 SMOG 12.6, Coleman-Liau 13.7, and Automated Readability Index 12.3. Readability score estimates became more consistent as the length of the passage examined increased, with no noteworthy improvements beyond 900 words. Among the five readability tools, scores typically differed by two grade levels, but the scores should have been the same. These differences were due to how compound and hyphenated words, slashes, numbers, abbreviations and acronyms, and URLs were counted, as well other punctuation and text elements. These differences occurred because the sources for these equations often did not specify how to score various punctuation and text elements. Of the tools examined, the authors recommend Microsoft Word 2013 for Windows if the Flesch-Kincaid Grade Level is required.

 

Rain & Lightning

After the rain. Personal photograph taken by Mike Anthony biking with his niece in Wirdum, The Netherlands

Today at 15:00 UTC we examine the technical literature about rainwater management in schools, colleges and universities — underfoot and on the roof.  Lightning protection standards will also be reviewed; given the exposure of outdoor athletic activity and exterior luminaires.

We draw from previous standardization work in titles involving water, roofing systems and flood management — i.e. a cross-cutting view of the relevant standard developer catalogs.   Among them:

American Society of Civil Engineers

American Society of Plumbing Engineers

ASHRAE International

ASTM International

Construction Specifications Institute (Division 7 Thermal and Moisture Protection)

Federal Emergency Management Agency

FM Global

IAPMO Group (Mechanical and Plumbing codes)

Institute of Electrical and Electronic Engineers

Heat Tracing Standards

International Code Council

Chapter 15 Roof Assemblies and Rooftop Structures

Why, When, What and Where Lightning Protection is Required

National Fire Protection Association

National Electrical Code: Article 250.16 Lightning Protection Systems

Lightning Protection

Underwriters Laboratories: Lightning Protection

United States Department of Agriculture: Storm Rainfall Depth and Distribution

Risk Assessment of Rooftop-Mounted Solar PV Systems

Readings: The “30-30” Rule for Outdoor Athletic Events Lightning Hazard

As always, our daily colloquia are open to everyone.  Use the login credentials at the upper right of our home page.

“Rainbow Connection”

The “lightning effect” seen in carnival tricks typically relies on a scientific principle known as the Lichtenberg figure or Lichtenberg figure. This phenomenon occurs when a high-voltage electrical discharge passes through an insulating material, such as wood or acrylic, leaving behind branching patterns resembling lightning bolts.

The process involves the creation of a temporary electric field within the material, which polarizes its molecules. As the discharge propagates through the material, it causes localized breakdowns, creating branching paths along the way. These branching patterns are the characteristic Lichtenberg figures.

In the carnival trick, a high-voltage generator is used to create an electrical discharge on a piece of insulating material, such as acrylic. When a person touches the material or a conductive object placed on it, the discharge follows the path of least resistance, leaving behind the branching patterns. This effect is often used for entertainment purposes due to its visually striking appearance, resembling miniature lightning bolts frozen in the material. However, it’s crucial to handle such demonstrations with caution due to the potential hazards associated with high-voltage electricity.

Electrical Switch Station #8

This project restores the Old Art Gallery building for a new electrical switching station. The 1904 building was originally the campus powerhouse, supplying electricity and steam to the young Berkeley campus. As the campus grew, power demands exceeded its capacity and, in 1930, a new central plant opened in the southwest part of campus. In 1934, the former powerhouse building reopened as a gallery to display art and served this purpose until a new University Art Museum opened on Bancroft Way in 1970. The building was subsequently used for storage for more than 50 years.

In restoring and structurally improving the Old Art Gallery building to house the new Switch Station #8, the small brick building that began its storied life as a powerhouse more than 100 years ago will become a key component in UC Berkeley’s 100% clean energy future.

IEEE TV: Overview of UC Berkely Resistance Grounded Campus Power System

Campus Bulk Electrical Distribution

High Voltage Electric Service

 

Lightning Protection Systems

“Benjamin Franklin Drawing Electricity from the Sky” 1816 Benjamin West

 

Benjamin Franklin conducted his famous experiment with lightning on June 10, 1752.

He used a kite and a key to demonstrate that lightning was a form of electricity.

This experiment marked an important milestone in understanding the nature of electricity

and laid the foundation for the development of lightning rods and other lightning protection systems.

 

Seasonal extreme weather patterns in the United States, resulting in damages to education facilities and delays in outdoor athletic events — track meets; lacrosse games, swimming pool closures and the like — inspire a revisit of the relevant standards for the systems that contribute to safety from injury and physical damage to buildings: NFPA 780 Standard for the Installation of Lightning Protection Systems

FREE ACCESS

To paraphrase the NFPA 780 prospectus:

  • This document shall cover traditional lightning protection system installation requirements for the following:
       (1) Ordinary structures

       (2) Miscellaneous structures and special occupancies
       (3) Heavy-duty stacks
       (4) Structures containing flammable vapors, flammable gases, or liquids with flammable vapors
       (5) Structures housing explosive materials
       (6) Wind turbines
       (7) Watercraft
       (8) Airfield lighting circuits
       (9) Solar arrays
  • This document shall address lightning protection of the structure but not the equipment or installation requirements for electric generating, transmission, and distribution systems except as given in Chapter 9 and Chapter 12.

(Electric generating facilities whose primary purpose is to generate electric power are excluded from this standard with regard to generation, transmission, and distribution of power.  Most electrical utilities have standards covering the protection of their facilities and equipment. Installations not directly related to those areas and structures housing such installations can be protected against lightning by the provisions of this standard.)

  • This document shall not cover lightning protection system installation requirements for early streamer emission systems or charge dissipation systems.

“Down conductors” must be at least #2 AWG copper (0 AWG aluminum) for Class I materials in structures less than 75-ft in height

“Down conductors: must be at least 00 AWG copper (0000 AWG aluminum) for Class II Materials in structures greater than 75-ft in height.

Related grounding and bonding  requirements appears in Chapters 2 and Chapter 3 of NFPA 70 National Electrical Code.  This standard does not establish evacuation criteria.  

The current edition is dated 2023 and, from the transcripts, you can observe concern about solar power and early emission streamer technologies tracking through the committee decision making.  Education communities have significant activity in wide-open spaces; hence our attention to technical specifics.

2023 Public Input Report

2023 Public Comment Report

Public input on the 2026 revision is receivable until 1 June 2023.

We always encourage our colleagues to key in their own ideas into the NFPA public input facility (CLICK HERE).   We maintain NFPA 780 on our Power colloquia which collaborates with IEEE four times monthly in European and American time zones.  See our CALENDAR for the next online meeting; open to everyone.

Lightning flash density – 12 hourly averages over the year (NASA OTD/LIS) This shows that lightning is much more frequent in summer than in winter, and from noon to midnight compared to midnight to noon.

Issue: [14-105]

Category: Electrical, Telecommunication, Public Safety, Risk Management

Colleagues: Mike Anthony, Jim Harvey, Kane Howard


More

Installing lightning protection system for your facility in 3 Steps (Surge Protection)

IEEE Education & Healthcare Facility Electrotechnology

Readings: The “30-30” Rule for Outdoor Athletic Events Lightning Hazard

Churches and chapels are more susceptible to lightning damage due to their height and design. Consider:

Height: Taller structures are more likely to be struck by lightning because they are closer to the cloud base where lightning originates.

Location: If a church or chapel is situated in an area with frequent thunderstorms, it will have a higher likelihood of being struck by lightning.

Construction Materials: The materials used in the construction of the building can affect its vulnerability. Metal structures, for instance, can conduct lightning strikes more readily than non-metallic materials.

Proximity to Other Structures: If the church or chapel is located near other taller structures like trees, utility poles, or buildings, it could increase the chances of lightning seeking a path through these objects before reaching the building.

Lightning Protection Systems: Installing lightning rods and other lightning protection systems can help to divert lightning strikes away from the structure, reducing the risk of damage.

Maintenance: Regular maintenance of lightning protection systems is essential to ensure their effectiveness. Neglecting maintenance could result in increased susceptibility to lightning damage.

Historical Significance: Older buildings might lack modern lightning protection systems, making them more vulnerable to lightning strikes.

The risk can be mitigated by proper design, installation of lightning protection systems, and regular maintenance. 

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