Building codes and standards are far from perfect, but complacency and ineptitude in the design industry is where the real problem lies.

Disclaimer: You may or may not agree with these views. I originally wrote this opinion article in response to a question about how I felt what direction building codes and standards should be heading in the future. If this bothers you, tell me why. If you agree, tell me why. Mature, educated individuals debate these topics for a reason; to agree on the best solution to a problem or situation. Without productive discourse, our society does not advance.

Changing the way building codes are written or enforced is only a symptomatic treatment for the larger underlying cause of industry frustration. The real culprit is a disturbing lack of competence, training, experience, or sense of responsibility in those who either must comply with or enforce local, state and national codes for building and life safety.

I have been in the design and construction industry for over 20 years, and a licensed architect since 2004. I’ve worked in small and large architectural firms from Washington to Florida, and on my own as a sole proprietor. I’ve worked in construction; with at least some experience in nearly every trade category on both residential and commercial projects. I was a state and federal surveyor, inspecting long‐term care facilities including nursing homes, assisted living facilities, adult daycare and intermediate care facilities for those with intellectual disabilities. I inspected facilities for compliance with licensing rules and nearly 100 different national codes and standards. I have worked alongside and opposite of architects, engineers, contractors, sub‐contractors, owners, operators, developers, city officials, inspectors and the end‐users and occupants of hundreds of buildings. Over the last eight to ten years, I have focused a great deal of my professional time on learning and teaching others across the industry how to comply with adopted codes and standards. I have been nicknamed a “code geek”; a label I’m proud to wear.

In that time, building codes, testing procedures and products have become more complex, and at times more difficult, to understand. A very large percentage of architects, engineers and contractors frequently complain about building codes getting out of control or various authorities overstepping their jurisdiction. While I believe there are changes that can be made to how codes are written and structured, the real solution lies with the individual whose responsibility it is to protect the health, safety and welfare of the public; the architect.

Architects are responsible for knowing and coordinating a tremendous amount of technical information, while listening to the needs of their clients and creating something functional, pleasing to be in, healthy and safe. It’s that last requirement that eludes so many architects; safety. This concept would include nearly every chapter and requirement in most building or life safety codes. I can somewhat forgive, or at least understand, a general contractor’s lack of code knowledge or understanding, but architects in the United States are held to a higher standard just by the mere fact they are licensed, educated and trained professionals. Every architect has the ability and the obligation to create the safest environment they can. The disturbing reality is that code compliance and thoughts of building occupant safety are left to the end of a project as an afterthought and then treated as a hindrance to good design rather than its single most important aspect.

The lack of knowledge in codes and life safety systems by today’s architects is due to inadequate education, little to no post‐education training, and very little sense of urgency by those licensed to practice architecture.

Education, or a lack thereof, is where the issue begins. Although not every architect is a member of the American Institute of Architects (AIA), most state licensing laws emulate the AIA’s basic code of ethics and standards of professional practice. The AIA defines the concepts of Health, Safety and Welfare (HSW) in The Architect’s Handbook of Professional Practice as:

Health: Aspects of architecture that have beneficial or salutary effects on occupants and users of buildings or sites and address environmental concerns.

Safety: Aspects of architecture intended to limit or prevent accidental injury or death of occupants and users of buildings or sites.

Welfare: Aspects of architecture that engender demonstrable positive emotional responses from, or enable equal access by, users of buildings or sites.

AIA’s Continuing Education System (CES) HSW courses fall within nine different categories, three of which mention safety or safety related topics:

Building systems: Structural, mechanical, electrical, plumbing, communications, lighting, acoustics, egress, security and fire protection

Design: Urban planning, master planning, building design, site design, interiors, safety and security measures

Legal: Laws, codes, zoning, regulations, standards, life safety, accessibility, ethics and insurance to protect owners and the public (from

Considering safety and security is mentioned in at least one third of continuing education categories and is one of the most important aspects of our profession, it stands to reason that a substantial amount of time should be spent by every licensed architect in attaining the knowledge needed to adequately protect the occupants of our buildings from harm. Sadly; this is far from the truth.

I personally graduated with my Bachelor of Architecture and Bachelor of Science in Architectural Studies from Washington State University in 1998 (Magna Cum Laude). Over 12 semesters and a total of 157 credit hours; the total number of classes dedicated in any way to codes, standards or fire protection was ONE. A single, two credit hour class that more than half of my classmates failed to pass the first time. For full disclosure, I received an ‘A’ in the class on the first try. That is only 1.2% of my total credit hours, and as any former architectural student knows; a minuscule fraction of the time spent actually studying or working in school. As of this paper, my alma mater no longer requires bachelor or master’s degree students to take the codes class I took (ARCH 472). It is now offered as an optional elective. Most university programs I have researched are no better.

The National Council of Architectural Registration Boards (NCARB), requires accredited university architectural programs to provide a minimum of three (3) hours out of 150 total toward “Laws and Regulations”. That’s two percent of the total hours in an accredited architectural program dedicated to educating architects on how to protect the safety of the general public as well as contractual obligations and other legal matters. That’s not only disturbing, it’s absurd.

The 2018 AIA Conference on Architecture in New York City offered more than 650 sessions on a wide variety of topics affecting architectural practice today, including several on resilience and designing with natural hazards in mind. Out of 650 sessions, I could identify only one that was devoted to the safety of a building’s occupants from internal hazards. One single session (TH205) discussed aging buildings, the jurisdictional issues with renovations and the need to prevent building material collapse due to aging. This lack of continuing education opportunities appears to directly mirror the lack of emphasis on teaching building safety in our educational system.

If the initial and continuing educational systems set in place do not emphasize (and follow through) on building and occupant safety, then where does that experience and knowledge come from? At the moment, it comes from professional organizations that publish the various model codes and standards adopted across the country. The International Code Council (ICC) and the National Fire Protection Association (NFPA), are the premier organizations in the United States that emphasize life safety and fire protection / prevention as a critical priority. A small percentage of the individuals who belong to or work with these organizations are licensed architects. A significant amount of participation comes from public jurisdictions such as city and state governments, first responders like fire fighters and paramedics, building officials, inspectors and other individuals whose entire career revolves around public safety.

This is where the disconnect between Architects, building codes and code enforcement begins to get worse. The vast majority of Architects I have met and/or worked with do not understand the most basic of building code issues; What is a building code and how is it created and enforced? The fact that a jurisdiction’s building code is actually enacted by law, and only subject to official interpretation by the jurisdiction that has passed that law, seems to elude even the most senior architects. This lack of understanding leads to an immediate adversarial relationship between the architect (required by their license to protect public safety), and a local city government for example (required by law to protect the safety of its residents). Both sides are supposed to have the same end goal, and the code is a set of rules and procedures to ensure both sides have done their best to ensure the safety of the public. I do have to acknowledge that many of these issues go both ways though, as public sector employees with no formal training or experience in design and construction can cause identical problems. The same lessons can be applied  to both sides.

As an architect progresses in their career, the knowledge and expertise needed to design safe and code compliant buildings should increase. The lack of initial knowledge and inadequate continuing education, training or even discourse among architects on this subject leads to the current frustration over the codes themselves. Any person, organization or interest group that has not spent a large percentage of their time devoted to building safety cannot adequately effect change on the way codes are written without first changing the system that caused the issue.

The prime focus for any group of Architects that is looking to make a positive impact on today’s codes and standards should be education and training first.

‐Shawn Gillen, AIA

Vice President, DFD Architects

Electricity, Part Two

AC/DC jokes aside, this is important current information.

AC/DC jokes aside, this is important current information.

So, by now, I assume you have read the previous post, Electricity: Part 1, at least five or six times to really grasp the intricacies of what electricity is and how it relates to the transfer of energy. You may also have read it once, fallen asleep and Google led you back here to part two against your will. Either way, I hope you enjoy the following discussion on the topics of electrical loads, alternating vs. direct current, single phase vs. three phase power, and the generation of electrical energy. Please enjoy it, I’ve lost a lot of sleep working on it. Sorry; that was supposed to be an inner monologue comment.

At this time, I’d like to ask for patience from those who are not big fans of geometry, trigonometry or other forms of mathematics. I’ll try and keep some of these concepts as simple as possible, while trying not to offend the majority of engineers, mathematicians or academics by being partially or even totally wrong. I will also try and keep the electrical jokes to a minimum. This subject is not for everyone so I make no promises.


In Part One, I introduced the idea of an electrical circuit. Electrons and the electromagnetic energy they carry will not flow from one pole to another unless their path is fully connected. Flipping a switch in your home either breaks the circuit (literally creates a gap in the wiring), or completes an electrical circuit and allows the flow of electrons. The following images show the simplest of circuits; one with a battery (a power source), wiring (path) and a light bulb, where the flow of current travels from one terminal of the battery, through the wire into the light bulb, causes the bulb’s filament to glow brightly and then continues on through the wiring to the battery’s opposite terminal. The second image is similar to the first, but the power source in this case is an AC Generator, so the flow of electrons change directions at a certain frequency. We will get into the differences between AC and DC later in the discussion.

Direct Current Circuit

AC Current Circuit

Every electrical circuit needs both a power source and something to resist the flow of electrons. Without some resistance, electrons will flow very quickly through a conductor. Given no speed limit (and no fear), drivers on an interstate would drive as fast as they can. If everyone drove like they were qualifying for the Daytona 500, you can imagine how many accidents would occur and the entire transportation system would break down. Electrical current is no different. If permitted, electrons will move as fast as possible in larger numbers and would eventually exceed the wire’s ability to handle the heat generated by the flowing electrons. When this happens, the wire can actually melt or catch its insulation on fire. A common cause for this type of excessive current is a “short circuit” where someone directly connects the two poles of a battery, or when a current carrying conductor (wire) comes in contact with metal objects or people; allowing current to flow unimpeded into them or into the ground. Resistance keeps the flow of electrons in check. For any normally operating circuit, this is not a problem since the entire point of electricity is to supply energy to some kind of device or equipment. The component of a circuit that utilizes the energy being transported and provides some resistance is known as a load.

Loads can be categorized into many different groups, but the most common are resistive, capacitive, and inductive. I know, the terms are beginning to sound complex and you may have started dozing off, but think of them as loads that resist the flow, capture the flow, or induce their own flow of electrons. It’s an over-simplification, but it works for me.

Types of Loads


Resistive loads are some of the most commonly known (or thought of), and are characterized by the fact they create heat (and/or light), the voltage and current are in phase with each other (more on phase later), and they do not generate their own magnetic field. Common resistive loads would include incandescent light bulbs and most electric heaters.

Resistive loads take advantage of the fact that some metals are conductive, but put up a fuss when they are energized. Much like a teenager when they are asked to clean their room; they are fully capable of doing so, but they sure put up a lot of resistance to do so, and cause their parents tempers to rise. I know it’s a thin comparison, but as a parent, its painfully relevant.

Certain elements such as Tungsten, used in common incandescent light bulb filaments, and an alloy used in heating elements called Ni-chrome (a mixture of Nickel and Chromium), are conductive, but when electrical current is passed through them, they emit much of the energy as either light, heat or both. Given the fact that only one of these results is typically desired, the balance of the energy used is wasted. This makes resistive loads very simple, but also very inefficient.


Devices used as capacitive loads are commonly referred to as capacitors. I know; big shock (the puns don’t stop here folks). Capacitors are capable of storing an electrical charge that can be released at a desired speed and quantity. Capacitors are not unlike a short-term rechargeable battery, but are used to store a large charge that can be released nearly all at once, or released slowly to provide a more even voltage or current. Although used in nearly every electronic device made today that can plug into an outlet, some better-known examples of devices that heavily rely on capacitors would be camera flash-bulbs, defibrillators and joy buzzers (although the last item is not a very safe or nice use of a capacitor, and no I’m not suppressing painful childhood experiences).


Inductive loads can seem more complex, but are one of the essential reasons humans learned how to harness the power of electricity.

As discussed in Part 1 of this post, we learned that passing electrical current through a conductive material creates a magnetic field. In single conductors the field is negligible, but when current is passed through a coil made of some conductive material, a larger magnetic field is created. The exact opposite is also true. If a coil of wire is passed through a magnetic field, it introduces a flow of current in the coil / conductor. Simply put; pass a magnet by a coil you get current in the coil. Energize a coil and you get a magnetic field.

This behavior of inductance is the reason that generators are able to create a flow of electricity and why motors are able to transform electrical energy into mechanical movement. The discussion of inductance is a substantial one on its own, and we could spend hours talking about induced voltage, power factors, and other engineering type stuff, but I’m stopping here. I don’t have the capacitance to go on, so I’m going to focus on how inductance allows for the creation of electricity as we use it in residential and commercial buildings across the world.

I’m a fan of AC/DC, and it’s not just a phase.


Let’s talk about AC, DC, Edison and Tesla (the man, not the car manufacturer).

Thank you to Maggie Ryan Sandford at for the following information, and lets be honest; most of the words.

For those geeks like myself that enjoy a bit of scientific history and trivia, this may not be new information, but to everyone else, the story of Alternating Current (AC), Direct Current (DC), Thomas Edison, Nikola Tesla and Niagara Falls sounds like a made-for-TV movie.

Nikola Tesla, a Serbian by parentage, began working for the Continental Edison Company in Paris in 1882. After gaining praise from his supervisor, he was invited to the US to work alongside Thomas Edison himself. Although Edison thought the man’s ideas were “splendid”, he found them “utterly impractical”. Edison and Tesla both worked long hours, were egocentrics and required little sleep (don’t they sound like a lot of fun to be around… wait, that sounds a lot like me… never mind). Their contrasting work and personal styles, mixed with what seems like sleep deprivation, led to many long, grumpy hours in the workshop.

Edison’s least favorite idea of Tesla’s was the concept of using alternating current technology to bring electricity to the people. Edison was much more partial to his own direct current system, and maintained that the lower voltage from power station to the consumer was safer. AC technology allows for the flow of energy to periodically change direction, and is more practical for transmitting massive quantities of energy over long distances. At the time, DC systems only allowed for a power grid within a one-mile radius of the power source (talk about a case of NIMBY: Not In My BackYard). The conflict between the two technologies, as well as Edison and Tesla’s feud, became known as the War of Currents, hence the not so hidden meaning behind the band name AC/DC.

Tesla eventually sold most of his patents to George Westinghouse (not an unfamiliar name to those familiar with power generation), who built one of the first AC power plants at Niagara Falls to power New York City, and then used the same principles to create much of the modern power grid we have today.

Edison wasn’t wrong however, as the higher voltages of AC are not safe or practical for use in smaller consumer electronics or appliances used in the home; hence the myriad of “power supplies” and converters used in our everyday lives. These converters and power supplies change the higher-voltage alternating current into a lower voltage direct current that can be used more effectively.

So AC and DC technology have been around for quite some time, but what is the difference?

Direct Current

Direct Current (DC) is electrical energy supplied at a constant voltage (approximately). DC is normally used at levels of 24 volts and lower, but can be occasionally seen higher. If plotted on a graph of voltage over time, it may look like the following diagram:

Direct Current Graph

DC is pretty much the standard for point-of-use electrical needs in consumer electronics and anything else that requires very precise and consistent current flow. DC loads can be resistive, capacitive and inductive.

Alternating Current

Most of the electric power in the world is AC. Electricians work with AC about 99% of the time, given its wide use in building electrical systems and its ability to transport energy over long distances. One of the biggest advantages of AC is that is can be transformed and DC cannot. A transformer can step up or step-down voltages as needed for certain devices and depending on what stage of transmission the energy is in. As power always equals the voltage times the amperage, a much larger amount of energy can be transmitted at very high voltages without having to increase the amperage (and therefore wire size). Tesla was a very smart man (if not sometimes foolish; can you imagine what he’d be worth if he hadn’t sold his patents).

Although other methods are available, the most common way of producing AC is by rotating a magnetic field past coils of conductive material, producing an electric current (that whole inductance thing again). The same effect can be created by rotating coils around a stationary magnet. In either case, an electric current is produced in the coil. When the coil is closest to the positive pole of the magnet, the maximum voltage is created in a positive direction. As the magnet is rotated further, the voltage drops increasingly faster until it reaches zero at the time the poles of the magnet are the farthest from the coil. As the magnet continues to rotate, the negative pole gets closer to the coil and the voltage in the coil becomes greater in the negative direction. One complete rotation of the magnet results in one “cycle”, where the voltage starts at zero, reaches its maximum positive value, reaches zero again, reaches its maximum negative value and then returns to zero. The term for cycles per second is called hertz. In the United States, AC is normally provided at 60 Hz (60 cycles per second). Just blew your mind a bit didn’t it? I hope it didn’t hertz too much.   Sorry, I couldn’t resistor.   I kill me.

The diagram below shows the relationship between a rotating point on a circle and the resulting rising and dropping of the voltage. This resultant form is known as a Sine wave, and is one of the most commonly seen wave-forms in nature. Sine waves are also seen in radio waves and any other machine with rotating motion.

Single Phase Animation

Single Phase vs Three Phase

Those professionals who deal with commercial projects have heard the term “Three-Phase Power” more than once, and even the typical homeowner has heard things like “120/240”. I’m sure those terms scare even electricians sometimes as electricity should just be on or off right? Why all the rocket science?

Amazingly, it’s not really difficult.

Single phase power is created when you rotate a magnetic field past one or more connected coils. The resulting voltage and current is always “in phase”, and three times every cycle the voltage is zero. If you generate 120 volts of electricity and then add it to 120 volts of electricity in the same phase, you get double the voltage. This is considered “single-phase” power. In typical residential electrical services, the power company brings two conductors that can each carry 120 volts and a neutral. If you connect say a motor to one of the “hot” conductors and the neutral, it will receive 120 volts. If you connect the motor to both hot conductors, you will get twice the voltage: 240V. Refer to the following diagram to see how the coils of a single-phase generator are “tapped” to get 120 or 240 volts.

Single Phase Power Schematic

Three-Phase Power

Three-Phase power is created by rotating a magnetic field past coils that are spaced 120 degrees apart from each other. Why should this make a difference?

Refer to the following diagrams for clarification, but you’ll quickly see that by spacing the coils equally apart, the sine waves created are also exactly 120 degrees apart. This means that when two or more of the phases are connected together, the resulting voltage never drops to zero. Because the voltage in each phase is offset at any one point, the maximum voltage between two or three phases is not double the single-phase voltage of 120, instead it is equal to the maximum voltage times . If the single phase maximum voltage is 120, then the maximum voltage using two or three of the phases is 208V. I could further explain this correlation using vectors and trigonometry, but don’t you think I’ve beaten you up enough at this point?


3-Phase Diagram

Three Phase Power Schematic

Why use three-phase power?

Three-phase connected motors are much more efficient with the same power and can be used to run longer and with less overall work. If every phase is providing voltage at some point, the motor is never without power. Newton’s 3rd law of motion: A object in motion tends to stay in motion. Keep it going and it takes less work to move it!

OK, time for a metaphor!!

Let’s say you were pushing a small child around on a merry-go-round (yes, they were a very popular playground element before lawyers got involved. See Whatever happened to merry-go-rounds?). One person standing in place could push on the merry-go-round once every time it went around and keep it moving. It would slightly slow down before each push, but you could keep it going. Now put ten kids on that same merry-go-round and one person pushing seems a bit daunting; But, if you were to position three adults around the merry-go-round and each one pushed every time the same spot came by, they’d be pushing three times as much and the fun would never stop; well at least until some poor child decided they’d held onto their lunch long enough. As I’ve said before; metaphors have their limits.

Three phase power is generally limited to commercial use due to the higher number of conductors, and commonly higher voltages, but is nonetheless very common and much more efficient.

Ok, if you have made it this far, I commend your perseverance (or stubbornness). If you understand everything I’ve talked about; please call and re-explain it to me. I may have dozed off in the middle while typing. For your moment of Zen, please enjoy the following animation of a full three-phase genset I modeled. It shows the parts flying away in fantastic fashion. I will try and elaborate on the various parts of the genset in a later post, but for now, enjoy the model and animation that was way more complicated than necessary.

Thank you.


All graphics and animations in this post, with the exception of the two photos were created by DFD Architects, Inc., ©2018 DFD Architects, Inc. ALL RIGHTS RESERVED. No image, video or animation on this post may be reproduced, transmitted, stored, or used in any form without the prior written permission of DFD Architects, Inc. I’m not kidding.

Gracious Acknowledgements to the following sources for information and selected passages, I couldn’t have written this without their guidance or copying their words:

Delmar’s Standard Textbook of Electricity, Sixth Edition. By Stephen L. Herman. Copyright 2016, Cengage Learning. Kindle Edition.

AC/DC: The Tesla-Edison Feud, by Maggie Ryan Sandford, July 10, 2012.

Thank you especially to my father, John D. Gillen, for passing along just enough of his electrical engineering expertise to make me a geek but remain somewhat socially acceptable.

p.s., I’ll buy a beer for the first (over 21 years of age) person in the State of Texas to correctly identify the location of the facility on the cover image (location name and affiliation). Geeks have to stick together! (Follow up: I’m proud to say my father was the first to get this correct; Extra points to Loyd Dittfurth for also identifying exactly where the image itself came from). For those who still haven’t gotten it; its in a cold and snowy place far far away.

Hurricane Harvey; an opportunity for giving back and moving forward

It has been several months since my last post. While my own life has been slightly more chaotic due to the arrival of Hurricane Harvey on August 25, 2017, it is nothing in comparison to struggles of those caught directly in its path. The past seven weeks have been eye opening and life changing for Millions of Americans. Harvey is only one of three storms that have wreaked havoc on the lives of so many.

I’m hoping that by sharing my own story, you may think about your own and how you could help more. In addition to speaking at several upcoming conferences, I will be posting additional information about challenges and successes here in Texas following Harvey, and continuing to educate about the same topics I have already started.

For the last 7 plus years of my career, I have narrowed my professional focus on the health, safety and welfare side of the architectural profession. After the recession in 2008 I took a position with the State of Texas as a state and federal surveyor / inspector for licensed long-term care facilities. As life safety is one of the prime concerns in nursing, assisted living and other healthcare occupancies, I began to focus more and more on code compliance and whatever was necessary to protect the lives of those that could not protect themselves. It was not unexpected that in 2010 I also joined the Texas State Guard. The TXSG is a non-federalized branch of the Texas Armed Forces with a civil mission to provide assistance in times of disaster through evacuations, shelter management, supply distribution, evacuee tracking systems and numerous other jobs. The TXSG was a purely volunteer group, but I received formal training in FEMA NIMS, NICS and other programs necessary to fulfill our mission. While my service in the TXSG was for only a short time, and I never had to put myself in mortal danger, I learned a great deal about disaster response and what it means to serve for your fellow citizens.

I personally lived in Central Florida in 2004 when Hurricane Charley made its way across the state (and directly over our home). Having seen the damage that even a category one storm could do (it made landfall as a category four), I knew that I absolutely had to assist in any way I could when Hurricane Harvey slammed into the coast of Texas. I couldn’t sleep for days; frustrated I was unable to help with first-response relief efforts in all of those areas affected. If the logical half of my brain had not stepped in, I was about ready to buy a boat and head to Houston to assist in rescuing stranded residents.

The morning I learned that the regional chapters of the American Institute of Architects (AIA) and the Texas Society of Architects (The State level AIA Chapter known as TxA) were organizing training sessions for members to assist in damage assessments, I began preparations to deploy for as long as needed. I’m sure I was on the edge of annoying when it came to calling and emailing the fantastic people at TxA to make sure I was ready. After a full day of official training and some phone calls to another agency already in the field, I was left the next morning for the Coastal Bend area which included Rockport, Port Aransas, Aransas Pass and surrounding areas.

Thanks to the incredible support of my wife Stephanie Gillen and my business partner and best  friend Will Davies, I was able to make a big contribution. Over a period of 12 days away from home, I performed individual safety assessments; met with local officials across three counties; presented in front of county EOC teams; assisted in writing formal state assistance requests; performed windshield damage assessments; created detailed aerial maps and organizational systems, and then coordinated teams of 26-32 volunteers at a time.

I am now involved in organizing training sessions, collaborating with the national AIA office on new educational and advocacy programs for emergency preparedness, and working to create new systems for training, education for local governments and whatever is necessary to mitigate this and future disasters. At home, I have even talked with my daughter’s Girl Scout troop about what kind of help and donations are the most effective. I have already returned to the Rockport area to work with fellow architects to develop new tools and collaborate with local officials regarding awareness and education. I hope that involvement on a national level could advance preparedness, education and reduce damages incurred for Texans and anyone affected by natural (or man-made) disasters.

I love being an Architect. It’s what I’ve wanted to be since I was in 5th grade. What I do as an Architect has at times been blurred; having no specific direction or purpose. Over the last 7-8 years my focus has become much more clear. I am privileged to have been given the family, education, and resources necessary to develop my skills and expertise. I now know that it is my responsibility to use that privilege to protect those who cannot protect themselves, educate those who can, and give a helping hand to those who have been knocked down and need help rebuilding their lives. I can do this by strengthening my firm and improving the facilities we design and build for our current generations. I can collaborate with other professionals to prepare for and mitigate damage from future disasters to assist future generations. I can also help convince other architects, engineers and contractors to donate their talents and put the safety and success of other people first.

The health, safety and welfare of all my fellow citizens is not just an acronym (HSW) in front of each of my continuing education courses each year; it is my purpose, and the primary reason I am an Architect.

Electricity: Part One

The first in an energetic series of posts on what electricity is and how it’s used, generated and distributed.

We don’t consume electricity; we use energy; transforming it into different forms to make our world brighter, warmer (or cooler) and make work easier. We strive to conserve and efficiently use energy, but in the end, we really only change energy from one form to another. Energy never goes away; it just finds another job to do.

If electricity is only the transportation system for the energy we use, then what is electricity and how does it work?

Although the Money Pit is one of my favorite movies, here is an example of how electricity does NOT behave.

In the simplest of terms, electrical current is the excitement and flow of electrons. To understand what that means, we need to start with the most basic building block of all matter: the atom. All matter is made from a combination of atoms (either of one kind or multiple). Any substance that cannot be separated into a simpler substance by chemical means is considered an element. All known elements are cataloged within the ‘Periodic Table of Elements’, a table that has stressed out generations of high school chemistry students. The periodic table of elements describes the individual atomic characteristics of each element, and knowing those characteristics gives us more insight into how they all behave with each other. It’s not unlike knowing the personality types of your friends and co-workers.

The Periodic Table of Elements
Each atom is composed of three basic particles: the electron, proton and neutron. Protons and Neutrons are located in the atom’s nucleus, with the electrons orbiting around in a series of concentric “shells”. Science has uncovered even smaller particles that make up and hold together each atom’s structure, but for our purposes it is the negatively charged electrons (or their absence) that hold the secrets of electricity.

Early scientists such as a Frenchman by the name of Charles Dufay realized that certain materials became attracted to certain objects, but were repelled by others. The forces of attraction and repulsion are described as either a positive or negative charge. As neutrons have no charge, each atom’s nucleus has a net positive charge. As Paula Abdul’s 1988 hit described, “We come together, cuz opposites attract”. Objects with similar charges are repelled from each other, and those with opposite charges are attracted to each other.

At this point, I know that many readers are beginning to have flashbacks to early childhood science class and are wondering, “Where is he going with this? It’s about as exciting as watching paint dry.”

Excitement is exactly what electricity is all about. The outer shell (known as valance electrons) of each atom contains between one and eight electrons. Each atom seeks stability by filling up its outer shell with all eight; a nice calm retirement of sorts. Some atoms like the noble gases Argon and Xenon start out with their outer shells full; they’re calm, unexciting and don’t over-react. Other elements such as gold, silver and copper have only one electron in their outer shell and are more than willing to dance the night away in an attempt to lose that electron and settle down into a more stable existence (a very unlikely outcome given their propensity to getting over-excited). The following animation shows a copper atom, with only one electron in its outer shell. The nucleus, comprised of 39 neutrons and 39 protons is shown as a single sphere at the center (To be honest, I didn’t feel like modeling all 78 spheres in the nucleus; my obsessive nature does have its limits).

Atom Model Moving - 25fps 640x480
Copper (CU),  Animation © DFD Architects, Inc.
At the risk of perpetuating stereotypes, we can group elements and materials by how they behave when excited. In terms of electricity, elements and materials (combinations of elements) can be put into three groups:

Conductors, Insulators and Semi-conductors.

Elements with 3 or less electrons in their outer shells are generally conductors (although the exact number of electrons does not always determine which elements are the best conductors). Because they have lots of empty room in that outer orbit, they are less stable and more likely to lose their remaining electrons when bumped around (The bump theory is a commonly held explanation for how electrons are passed from one atom to another). Insulating materials such as wood, glass and rubber are combinations of elements that fill their outer shells by sharing their electrons with other elements. These materials are composed of elements such as Carbon, Oxygen, Nitrogen and Hydrogen. Alone these elements are not very stable, but combined they have found comfort and stability. Selective elements such as Silicon and Germanium are termed semi-conductors, and have 4 electrons in their outer shell. With a little encouragement these elements can be persuaded to lose an electron or two and become negatively charged. These materials have become indispensable in the development of solid-state circuitry and computers in general.

That bumping around of electrons in a conductor is precisely where the transfer of energy via electricity happens. Like billiard balls on a pool table, when the energy is introduced at one end (the player hitting the cue ball), energy is transferred from one ball to the next. Not all energy is passed from one ball to the next however. In billiards, you’d hear the sound of balls hitting, and if measured, you could see the heat generated by the instantaneous collision. With electrons in a conductor, that energy release may be heat, light and almost always a magnetic field.

Magnets? I thought we were discussing electricity?

Everyone has played with magnets as a kid (or adult). Those of us old enough to remember iron filing and magnet toys such as “Wooly Willy”, have seen what a magnetic field actually looks like. The following image shows a magnet with a negative and positive end (or “pole”) often termed a North and South pole.  The iron filings align with the resultant magnetic lines of force (or ‘flux’). No we are not going to enter into a discussion of whether Santa Claus or penguins reside on either pole (maybe in a later post).

Patterns of magnetic flux (iron filings and a magnet)
Magnetic fields, created by electrons flowing through a conductive material, are precisely what enables a generator or alternator to initiate the flow of electricity, and appliances such as motors to use that flow of electromagnetic energy to create mechanical movement.

This whole discussion can seem very theoretical, given that we can only see the results of what magnetics and electricity can do. So how do we measure that flow of energy across a conductor?

Before we talk about measuring electricity, it’s important to know why it flows at all. Electromagnetic energy will not flow through anything unless it has somewhere to go. OK, time for a few metaphors:

Everyone is familiar with water pipes in their house, or at least knows that water comes from somewhere when the faucet is turned on. Why doesn’t water flow continuously from the kitchen faucet? It doesn’t flow all the time, because without an open outlet (someone using that water), it will just sit nice and quiet in the pipe. Open a faucet, and the water begins to flow. Break a pipe or create a leak, and water will flow to places you don’t want it to. Electricity is very similar. Without a load, or something to use that energy, there is no need for the electrons to bump into each other and pass along their energy. Unlike the water in our pipes however, electricity wants to flow from a positively charged source to negatively charged one (this is according to popular theory, but let’s leave theory out of this for the moment as it gives me a headache). More often than not, that flow may be from a positive terminal of battery to the negative one, or a positive source to the earth itself (such as in a building’s electrical system). Without a complete “circuit” to follow, the electrons will have nowhere to go, and the flow of electricity will stop. If you provide a complete path for the electricity to follow, then it will happily oblige. There is a reason that they refer to the Formula One race car events as a circuit. If the road was open on both ends and didn’t connect, it would be a very short race. Yes, I’m aware that would be considered drag racing; metaphors have their limits.

Measuring the energy carried by electricity

Before I lose anyone, let’s talk about volts, amps and watts. In my next post we’ll talk about AC/DC, and by that I’m referring to Alternating and Direct Current, not the 80’s band from Australia. I’m sure everyone has heard the phrase, “It’s not the voltage you have to worry about; it’s the amps”. While partially true; why? It has to do with force and potential energy.

If electricity is the flow of electrons, then measuring energy carried by electricity must involve electrons right? Well, unless you have an incredibly powerful microscope, and someone who is really fast at counting, we’re going to need a standard to measure against for counting electrons. Here we learn about Charles-Augustin de Coulomb, a French physicist whom the standard imperial measurement of charge was named after (his story would be another post). One coulomb is equivalent to the charge of 6.242 X 1018 electrons. That’s a lot of electrons. In obnoxiously large numeric terms, that’s six quintrillion, two hundred and forty-two quadrillion electrons. That should be easy enough to put into an Excel spreadsheet, right? Well, instead of counting every electron over a period of time, how about we just divide the total number of electrons by a nice big number like a coulomb? Well it so happens that the volume of one coulomb per second is referred to as an ampere. Whoa! Amps are actually related to something physical?! Don’t get too excited, we’re still talking about theoretically numbers and some basic assumptions, but at least we have somewhere to start.

So if one ampere (normally referred to as an Amp), is a volume of electrons over time, then we should be able to measure the energy those electrons are moving with them right? Not so fast. Volume (or size) is one side of the equation, but we’re missing the other half. We need a push. We need that potential energy to work with.

Caution: Dangerous metaphors ahead.

What is potential energy? If your house was on fire, and you asked for a water hose; I’m sure you’d be rather upset if someone walked up with a garden hose connected to a hand pump. You’d prefer a fire hose connected to a rather large fire truck I’m sure. Why? The difference is in potential energy. Only so much water can flow through a garden hose. Given a bigger and stronger hose, you could push more water through it. Water is normally measured in volume over time; commonly gallons per minute. A garden hose can easily provide 10 gallons per minute, but so can a fire hose. The fire hose however has the potential to provide much, much more water if it is needed (which it usually is). Here’s another example: Let’s say you are sitting quietly at the base of ten-foot cliff, and a rock is perched very precariously above you. It’s not moving, but given a bit of a push, it could fall at any time. If that rock weighed a few grams, the potential for harm to your pretty head is minimal. If that rock weighed 10,000 lbs., then the potential for harm would be rather substantial. Unless it’s actually falling, both rocks are harmless. The 5-ton rock however has a much larger potential energy (it COULD exert a much bigger force).

Since electricity transmits energy, we need to know the volume of energy over time, but we also need to know the level of force with which it is delivered. In terms of water in a pipe, this potential energy is referred to as pressure (in pounds per square inch, or PSI). In the flow of electrons, this potential energy or pressure is called voltage. One Volt is the potential energy it would take to drive one amp of current against a given load (we’ll talk about loads in the next post).

Now we’ve brought energy and force into the equation. Flowing electrons mean nothing if they bump off a conductor one at a time, but if they flow in great numbers (along with their accompanying magnetic fields) with a large amount of force, then now we have energy we can use. With both volume and force, we can move almost anything.

So how do we measure the power or work that electricity provides? Enter the “Watt”. One watt is equal to one volt of potential energy times one ampere of flow. The watt is a measure of the real power that pushes, heats or illuminates. For comparisons, this would be similar to horsepower (735.5 watts), or foot-pounds of force per second (1.355 watts).

In electrical terms, the watt, is proportionately equal to the volts (the potential energy) times the amps (the volume of flow). 1 Watt = 1 Volt x 1 Amp. I know. Some of you just went… uh, duh, but the majority of people just had that little 13 watt LED light bulb (equivalent to a 60 watt incandescent bulb) go off in their head and said, “Oohhhh, I get it.”. You’re welcome.

So let’s stop there for the moment, because unless you’re an electrical engineer or a geek like me, you may need a week to recover from reading this post.

Next time we’ll talk about Direct Current, Alternating Current, Single-Phase Power, Three-Phase Power, generators and transformers. I know, you’ll have a tough time waiting, but it should be worth it.

In the meantime, here is your moment of Zen (Yes, I’m a fan of the Daily Show on Comedy Central):


I promise not to beg, but I would really welcome any comments; both good and bad (but constructive). The more feedback I get; the better my posts can be. Thanks!!


The Money Pit, Copyright NBC Universal, 1986

A Christmas Story, Copyright Warner Bros. Home Entertainment, 1983

Magnet and Periodic Table images are public domain and are available on

Why is electricity so hard to understand?

Grasping the concept of electricity is easy once you accept a very simple idea:

Grasping the concept of electricity is easy once you accept a very simple idea:

Electricity is only a transportation system.

We don’t use electricity in our homes, schools and businesses; we use energy. We need energy to do work. Electricity allows us to move the energy we need to do work from one place to another. That work could be mechanical movement, or the creation of light and heat. How do you capture the energy of a strong wind in West Texas; transport it hundreds of miles to your front porch, and then use it to make your ceiling fan blow a gentle breeze on your face on a hot summer evening? You use electricity to move that energy. You’re home or business’ electrical meter is not measuring electricity; it’s measuring the amount of energy you are using. Have you ever noticed that nobody uses the term “Electricity Conservation”? Why is that? Because you can’t consume or conserve electricity. We strive to efficiently use energy. We don’t use up the road as we drive down it, and we don’t run out of water pipe as we take a shower. The medium, or transport method, is entirely different from what moves along it. We are moving and converting energy.

In the end, energy only changes from one form to another. Stored energy is released when fossil fuels are burned to create heat, which boils water to create steam, that spins huge turbines engineered to transfer that energy electromagnetically wherever we need it. Instead of burning limited quantities of fuel, we also use wind turbines to convert mechanical movement into energy we can store and move. Energy never goes away; it just finds a new form and another job to do.

Wouldn’t you like to know why that light comes on when you flip the switch and be able to explain to your child what electricity really is? No, I’m not an engineer or electrician (although having a great electrical engineer for a Dad does help), but understanding and explaining the basics is something everyone can do. Through a series of posts in the coming weeks, I’m going to explain the underlying concepts of electricity, how we use it to transform and move energy, and explain the systems and equipment that allow us to harness the unbelievable power our universe provides us. It will involve some physics, a little chemistry, some easy math, funny examples of what electricity does not do, and hopefully just enough humorous metaphors to lighten the load (pun intended). In the end you probably won’t be ready to install a distribution panelboard, repair the control board in  your flat screen TV, or be qualified to go anywhere near a high voltage power line, but I think it will change the way you look at the world around you.

I hope it sparks your interest.

Fire burns, but let’s be clear on what that means

Man is the only creature that dares to light a fire and live with it. The reason? Because he alone has learned how to put it out. – Henry Jackson Van Dyke, Jr.

Humans have learned to utilize fire’s power and enjoy its beauty and warmth, but yet we are still learning to protect ourselves from its destructive nature. In order to improve, there must be meaningful conversations and collaboration between those who study, design for, live with and fight against fire. To do so, they must all speak the same language. The English language has so many different words for concepts and ideas that are nearly identical, yet each conveys slightly different emotions, details or opinions depending on context and intent. The simple fact that each word has specific meanings allows you to (hopefully) understand what I have written here. When lives are at stake, there is no room for confusion or arguments resulting from improper use of a simple word. Knowing the exact and agreed upon definitions to certain terms used throughout the various codes and standards is also often the biggest stumbling block to understanding key concepts. The following terms are not interchangeable, and it is therefore critical that everyone understands them.

Flammable, Combustible, Non-Combustible, and Fire-Resistance

All four of these are common throughout dozens of codes and standards; the term “combustible” is used in some form almost 300 times in the IBC alone. They are also used in everyday news reports and on thousands of product labels. Once you have the real definition, you’ll be amazed at how often they are mis-used and actually lead to incorrect assumptions.

The International Building Code (IBC) and NFPA 101 actually avoid defining three of these terms in a simple sentence or paragraph because in order to be classified under one term or another, the material must be tested in a recognized manner. If the definition of what combustible meant was summarized by a highly interpretable paragraph, nobody would ever fully agree on whether something was or was not combustible. Basing a definition on whether something has passed a consistent and widely accepted set of criteria and even testing helps to reduce interpretation errors.

The first two are often used interchangeably, but should not be:

Flammable versus Combustible

Here are some official definitions. Note that I’m including the definition of noncombustible because combustible is defined as anything that cannot be called noncombustible. Yes, I know the thought, “Well, Duh…” entered your head, but it’s actually an important point.

Flammable: capable of being easily ignited and of burning quickly – (1)

Flammable Material: A material capable of being readily ignited from common sources of heat or at a temperature of 600°F or less. – 2015 IBC

Combustible Material: A material that, in the form in which it is used and under the conditions anticipated, will ignite and burn; a material that does not meet the definition of noncombustible or limited- combustible. – 2012 NFPA 101

Noncombustible: A material that complies with any of the following shall be considered a noncombustible material:

(1)*  A material that, in the form in which it is used and under the conditions anticipated, will not ignite, burn, support combustion, or release flammable vapors when subjected to fire or heat

(2)  A material that is reported as passing ASTM E 136, Standard Test Method for Behavior of Materials in a Vertical Tube Furnace at 750 Degrees – 2012 NFPA 101

There are three key differences in these terms:

  • Flammable material ignites from common heat sources or at a temperature less than (or equal to) 600°F. Combustible material is ANYTHING that ignites, burns, supports combustion, etc… at any temperature or from any fire.
  • The term flammable is most commonly used to refer to fabrics, furnishings, decorations, clothing, and other such non-building related components. Combustible is more often used to describe a building material or finish that will burn.
  • Combustible materials are defined as those that would FAIL the ASTM E 136 test.

Using these definitions: All flammable materials are also combustible. Combustible materials are not always flammable. Whoa… what did he just say? Let me give an example:

A product that has been a big part of recent headlines is the metal composite material (MCM, or ACM) Reynobond PE®. It is composed of aluminum sheets (a non-combustible material) with a polyethylene foam core. Polyethylene foam ignites at a temperature of 340℃ (644℉) (2). Because the foam ignites at all it is considered combustible. The panels however would not be considered flammable as the aluminum skin does not burn (keeping flame away from the inner core under “common sources of heat”), and below 600℉; the foam core does not ignite. In this particular case, the material is NOT flammable by definition. It IS combustible. I would encourage you to read my first blog post for more discussion on the Grenfell Tower fire.

Ok, so flammable and combustible are different, but it’s just semantics right?

Noncombustible and Fire-Resistance

Let’s look at the other two terms: Noncombustible and Fire-Resistance / resistive. These unfortunately are used in similar ways, but do NOT have the same meaning.

Noncombustible: A material that complies with any of the following shall be considered a noncombustible material:

(1)*  A material that, in the form in which it is used and under the conditions anticipated, will not ignite, burn, support combustion, or release flammable vapors when subjected to fire or heat

(2)  A material that is reported as passing ASTM E 136, Standard Test Method for Behavior of Materials in a Vertical Tube Furnace at 750 Degrees C

– 2012 NFPA 101

Fire-Resistance Rating: The period of time a building element, component or assembly maintains the ability to confine a fire, continues to perform a given structural function, or both, as determined by the tests, or the methods based on tests, prescribed in Section 703. (Those tests are ASTM E 119 or ANSI/UL 263) – 2015 IBC

A material that will not ignite or burn in any way, such as steel, is considered non-combustible. Steel on its own however, does not maintain its structural strength when subjected to high heat, and therefore has a very low (if any) fire-resistance. It may sound hard to believe, but a heavy timber column (say 12 inches x 12 inches in dimension) will remain structurally sound much longer in a fire than the same size steel column.  Another common example is cementitious siding (known by the brand name HARDIEPANEL®). This product is non-combustible (3), but does little to confine a fire as it can quickly fall apart when subjected to an actual fire reaching more than 1,500℉, and therefore has little to no fire-resistance.

If you want to protect and separate the occupants of a building from a fire, you need materials and systems that are fire-resistive. They actually remain in place and hold together long enough to keep the fire away or hold the building up. There are fire-resistive systems constructed of non-combustible materials and just as many that are made with combustible materials.

Fire-resistance is not an issue of will it burn or not (combustible versus noncombustible); it is determined by how long a material or system will resist the fire and protect a building’s occupants.

It’s impossible to design, construct, or correctly maintain a building that protects its occupants if these terms are used incorrectly; besides, you’ll sound smarter using the right one.

More Information:

There are plenty of other terms related to building codes that are mis-used or mixed up that I know we’ll discuss later.

For additional information on fire-resistive properties of Aluminum Composite Materials (ACM) and the fire-resistant testing procedure ASTM E 119, please take a look at the following videos from Alucobond® and National Gypsum®.


  2. Q & A on Fire and Fire Prevention of Rigid Polyurethane Foam, May 2009, Translation into English by JUII Fire Safety Committee from revised Japanese text, December 2011, Japan Urethane Industry Institute (JUII).

Automatic Sprinkler and Fire Alarm Systems

Don’t believe everything you see in the movies; here is a layman’s guide to fire sprinkler and fire alarm basics.

The myths and misconceptions surrounding fire alarm and fire sprinkler systems in movies and television is pretty staggering. As a design professional, I roll my eyes every time I see a character activate a manual pull station resulting in every fire sprinkler going off. Of course you might say, “It’s a movie; lighten up!”. On one hand; you’re right. It is only fiction. On the other hand, the consistency in which fire alarm and fire sprinkler systems are incorrectly shown actually leads to complacency and misunderstanding. In the not so distant past, I actually explained how a sprinkler works to a coworker, and they were floored that what they’d see in the movies was not correct. Entertainment is fine; I’m a big movie person myself. When no one actually explains how the systems really work to the average person, and the movies are all they know, it could actually lead to a delay in evacuation or other events that could put a person’s life in danger. I’m not suggesting changing the movies; let’s just talk about how the systems actually work. I’ll try and do so in the least technical way possible. To start, here’s some examples (from two movies I actually like) of movie imagination with regards to fire alarm and sprinkler systems. After the show, I’ll follow with some basic concepts and history for you:

Concepts and History:

Automatic sprinkler and fire alarm systems are two crucial components of a building’s life safety systems. They are what’s known as active protective systems. Passive protective systems such as fire-resistive construction, protected stairways, smoke barriers and fire walls are intended to be the main line of defense in the protection of occupants against a fire. Fire alarms are there to actively notify occupants of a fire so they can evacuate, and automatic sprinkler systems are intended to help suppress the fire long enough for the fire department to arrive and extinguish the blaze. While typical light-hazard sprinklers may often extinguish a small fire, their purpose is to keep it from growing; not put it out. More specialized systems are actually designed to fully put out a fire, but those are normally reserved for high hazard occupancies such as large storage buildings, hazardous material handling and very large mercantile buildings such as big box stores like Home Depot, Costco or Walmart.

Automatic sprinkler systems have been in existence since the late 1800’s, beginning with Henry S. Parmelee’s invention of the first sprinkler head in 1874. While improvements have been made in sprinkler design and the various system components, such as valves and piping; the basic concept of automatic sprinkler systems has not changed that much in almost 150 years.

The earliest fire alarm systems involved nothing more than a person keeping watch in the streets who would then alert the fire brigade. With the invention of the telegraph in the early 1840’s by Samuel F. B. Morse, cities such as New York began to construct municipal alarm systems of communication between fire stations and government buildings. This reduced the time needed to alert the fire brigade and improved response time through better directions. By 1880, manual fire alarm signal boxes had been patented by John Gamewell and his brother-in-law James M. Gardiner. At that time, the Gamewell Company held a 95% share of the United States market for fire alarm systems. William B. Watkins designed the first electric fire sensor / heat detector in the early 1870’s and in 1873 formed the first private fire alarm company, Boston AFA; known today as AFA Protective Systems.

In the early 1900’s, leading fire alarm and fire sprinkler companies such as ADT (American District Telegraph), Holmes Protective, AFA, Grinnell and Automatic Fire Protection (AFP), established contracts with each other to supply detection equipment, sprinkler systems, sprinkler system supervisory equipment and central station monitoring services.

In 1939, Swiss physicist Ernst Meili invented an ionization chamber which could detect combustible gases in mines and a cold cathode tube that could amplify the small signal generated to a level sufficient to activate an alarm. By 1951, the first ionization smoke detectors were sold in the US. The photoelectric (optical) smoke detector was then invented by Donald Steel and Robert Emmark of Electro Signal Lab in 1972. The technologies and devices used in fire alarm systems have continued to advance, but the basic concepts remain the same.

Fire Alarm Systems: The Basics

Fire alarm systems are required to be installed in accordance with NFPA 72, the National Fire Alarm Code. (Disclaimer: The following explanations are in layman’s terms and intentionally omit and generalize some technical details, devices and system components for clarity).

Fire Alarm Systems are made up of three basic categories of devices:

  1. Initiating
  2. Notification
  3. Control / Transmission

Initiating Devices:

These components do exactly what you think they would; they initiate an alarm. They include both automatic and manual means of activating the alarm system. The most common manual device is the “Manual Pull Station”. This would be the red device on the wall labeled “Pull in case of fire” or something similar. When the handle of this pull station is moved it literally flips a switch inside the box that tells the system to go into “Alarm”.

The three most common automatic initiating devices are smoke detectors, heat detectors and sprinkler system flow switches. The first two are self-explanatory. When a smoke detector sees (or senses) smoke, it tells the system to go into alarm mode. If the heat detector senses a rise in temperature above a set point, it also tells the system to go into alarm mode. The third item is a component that few people outside the construction, design, or fire protection industries even know exists; the flow switch. A flow switch is a device installed into the piping of the fire sprinkler system just after the water pipes enter the building. The typical flow switch has a round “paddle” or disc that is directly inside the pipe and connects to a lever and electronic sensor. When the sprinkler system activates, water begins to flow through the pipes. When the water moves, this ‘paddle’ also moves; raises the lever and sets off the sensor. This tells the fire alarm system that a sprinkler has activated; also resulting in an alarm.

In a typical light-hazard occupancy sprinkler system ,which are the most common, this is the ONLY interaction between the sprinkler system and the fire alarm system. When water flows; the alarm goes off. It does NOT work the other way. Setting off the fire alarm DOES NOT activate any or all of the fire sprinklers. Unless the system being discussed is for very unusual situations like hazardous materials, locations with jet fuel, etc.; the fire alarm system and sprinklers are not set off electronically in any way. We’ll discuss how a sprinkler system works next.

Notification Devices:

These include two main appliances, commonly referred to as a horn and a strobe. The horn is what it sounds like; it’s that really loud and annoying noise maker that lets you know there is a fire and to GET OUT. The strobe is the light emitting device that flashes when the alarm activates. Strobes are there in case occupants are hard of hearing or ambient noise levels are high enough to prevent people from hearing the horn. The horn can also be a recorded announcement in some occupancies. These two devices are there to let you know a fire or another emergency is present and you need to act accordingly. Very commonly both devices are combined into a single appliance called… you guessed it: a horn-strobe. We look for humor in this subject matter wherever we can find it.

Control / Transmission Devices:

This is my own general category for the main Fire Alarm Control Panel (FACP), Fire Alarm Annunciator Panels (FAAP), and automatic dialing devices. All of the initiating and notification devices are connected to the FACP. When an initiating device is tripped, the FACP activates all of the notification devices to let people know there is a problem. If any systems are required to shut off when an alarm is activated (mechanical units, electronic door locks, magnetic door hold-opens, etc.), the FACP will send signals to that equipment accordingly. Most modern FACP’s also include the auto-dialer device. This is literally a phone / modem that calls a monitoring service and says, “We have an alarm. The following initiating devices were set off….” The monitoring company will then notify the fire department. As all of this is done electronically, there is very little delay between when a device is set off and when the fire department is notified. The FAAP (as shown below) is basically a twin to the control panel from the FACP that can be located at strategic locations without having to install the larger control box in public areas.

Fire Alarm Systems

Those are the fire alarm basics. Although the wiring, programming and code requirements surrounding what devices are required, where they go, and how they must work are more complex, the basic concepts of initiation, notification and transmission are pretty simple.

Fire Sprinkler Systems: The Basics

Automatic Fire Sprinkler Systems must be installed in accordance with NFPA 13, NFPA 13R or NFPA 13D. 13R is generally for multifamily and hospitality occupancies like apartments, condos, hotels, motels and dormitories. 13D systems are for single family homes or duplexes. The NFPA 13 compliant system is what you would normally see in any commercial, institutional, educational or other public type building. The 13R and 13D systems use the same types of sprinkler heads; they just have less restrictive requirements in where sprinklers are required, and what kinds of equipment and other devices are installed.

The central component to a sprinkler system is… no big surprise: the sprinkler.

Fire Sprinkler
Typical ‘pendant’ type sprinkler head

The most typical sprinkler installed has 4 main parts:

  1. The cap: a disc that covers the hole the water shoots out of;
  2. The thermal linkage: the colored glass tube or metal piece that bursts or melts at a certain temperature. The linkage holds the cap in place;
  3. The deflector: The metal disc or plate that the spreads the water out, and
  4. The frame: the “arms” of the sprinkler head that hold the deflector, cap and linkage all together.

So how does a sprinkler go off? Its rather simple. The most common thermal linkage you will see today is a glass bulb with a colored liquid inside. That liquid is a mixture of water and alcohol or glycol with a colored tint. The color indicates the temperature at which the bulb is designed to burst. Per NFPA 13, bulbs that are red in color activate at 155°F. Other colors such as green, yellow, or blue indicate higher temperature ratings.

When a fire gets large enough to raise the air temperature in a room (at the head itself) to a level equal to or above the head’s rating; the glass bulb bursts. With nothing to hold it in place; the water pushes the cap out of the way; water rushes through the opening (called the orifice), and then spreads out in a pre-defined pattern as it hits the deflector. That’s how a sprinkler gets activated. There are no electronics, no manual levers or special keyed switches. The bulb gets hot; it breaks; water comes out. The only heads that will go off in a fire are those that have been heated to that specific temperature.

If EVERY head went off in a building at once (as the movies like to show), the amount of water necessary would be as much as fifty to a hundred times greater than any normal building has available. Sprinkler systems are designed to have no more than 4-6 heads go off in a fire (that is a very general statement I know; the exact number of heads is a code requirement and up to the system designer and is dependent on a number of different factors). What you see in the movies is just not physically possible in any typical building. There are specialized systems in which a large number of heads are activated at the same time, but those are not used in any building the general public normally occupies.

There is of course more to a sprinkler system than just the sprinkler heads. Every head is connected to pipes made of steel or CPVC (specially designed plastic pipe). The pipes with heads on them are commonly referred to as branch lines, while the larger pipes that feed the branch lines are called mains. The single big pipe that supplies the mains is called the riser. The riser is located inside the building right after the main water pipe enters the building. The riser typically includes shut-off valves, pressure gauges, test valves, the flow switch (connected to the fire alarm system as mentioned above), backflow preventers, and other devices needed to maintain and test the system. A typical NFPA 13 system will also have a Fire Department Connection (FDC) at the riser (or a remote one that connects to the riser) which allows the fire department to connect a pump truck and supply the system with a higher flow and pressure than the normal water system may be capable of.

Main riser with valves, main drain and pressure gauges

The kind of system described above is known as a “wet” system because the pipes are always full of pressurized water. Water freezes however, so another common system known as a “dry pipe” system is often used in attics or other areas where no heat is available during winter months. In this system, the heads are actually the same, but the branch lines and mains are filled with compressed air. The water from the utility provider is kept at bay in the riser, by a special valve and the compressed air in the system itself. When a fire causes the sprinkler head bulb to burst, the process is the same, except the system has to first purge itself of the compressed air, and then the water comes rushing in behind. Same concept; it just slightly delays the water actually hitting the fire.

The basic concepts and components of a fire alarm and fire sprinkler system are not difficult to understand. In fact, they are simple enough that everyone should know how and when each system would go off, and how it generally works. Knowing these basics makes using them that much easier and safer.

Would you like know more?

This is a VERY broad overview of fire alarm and fire sprinkler systems. What components or requirements of these systems would you like to know more about?

Sources, Disclaimers and Copyrights:

  • Fire Alarm System Research – Where it’s been and where it’s going, Wayne D. Moore, P.E.

  • Sprinkler image: Courtesy of
  • Fire Alarm device images are the property of Potter Roemer Fire Pro., Copyright 1937-2016
  • Fire alarm control and annunciator panels images are the property of Silent Knight, by Honeywell, Copyright 2017.
  • Excerpt from Lethal Weapon 4, Copyright Warner Bros. Pictures, 1998
  • Excerpt from Casino Royale, Copyright Columbia Pictures, 2006
  • Fire Truck Image is the property of the City of Leander Texas Fire Department (actually one block from my office; thank you gentlemen).
  • Fire riser image is by DFD Architects, Inc., Copyright 2017.

All images and videos included or linked to are for reference and educational purposes only. All copyrights are the property of their respective owners.

Disclaimer: I am not a licensed fire alarm or fire sprinkler RME (Responsible Managing Employee) or installer. All fire alarm and fire sprinkler systems shall be designed and installed by appropriately licensed professionals in accordance with applicable state and local laws. The above commentary is from my personal experience and code knowledge, but should not be substituted for advice and direction from trained and licensed professionals in fire alarm and fire sprinkler design and installation.