Jul 18, 2022

In this solocast episode we are talking about initiation devices! What is the difference between a smoke detector and a smoke alarm? What are the codes and standards pertaining to smoke detectors? What are the different coverage approaches and types of smoke detector? Tune in to find out about all these topics and more.  

Transcription

Hello. Welcome to the solo cast of fire code tech in these episodes. It's just gonna be me, your host, Gus Gagliardi. There's gonna be a range of topics, but I'm gonna talk about specific technologies, installation, standards, codes, and how they work as well as some other interesting topics that don't neatly fit inside of the context of a normal interview.

Hello, all, welcome to fire code tech, the solo cast series episode 40. On this episode, we're speaking about smoke detectors. Yes. I went back through and cataloged some of the solo cast episodes, which basically means I took a look at the distribution between fire suppression and fire alarm videos. And I realized I'd done about half as many solo cast on fire alarms as I have on fire suppression topics.

So this episode, I wanted to speak a little bit more about smoke detectors because it is such a common fire alarm feature. Break down codes and standards, smoke detectors, and what that word means. What are the different types of smoke detectors? What are the different coverage options for smoke detectors?

But let's get into the episode. Don't forget to follow us on social media and hit that subscribe button. So you don't miss when I upload every Monday. Oh. And if you could give us a five star review on apple podcasts, that would be a huge. For this episode, we are taking a look at NFPA 72, the national fire alarm and signaling code specifically, we're looking at the 2022 edition.

For those of you who may not be aware most NFPA documents have a very similar layout, a standardized approach to how they develop their criteria. And the first three to four chapters. Very commonly have the same layout. And chapter three is usually where they will house definitions for whatever subject you are reviewing in the NFPA document.

So in chapter three of NFPA, 72, 20 22, we can find the definition for smoke detector. The specific section is 3.3 point 77 point 21 in its titled smoke detector. And it's pretty broad. It says a device that detects visible or invisible particles of combustion. So there are a pretty, I would say a large variety maybe to be more specific.

There are about, uh, six to 10 different types of smoke detector, and they all have different applications for which they are advantageous or disadvantageous to provide some context for our conversation for smoke detector. Let's talk about the word detector, because it is a crucial piece of this definition detector is to sense something or to provide a device that senses something.

So there are gas detectors, flame detectors, heat detectors. So you can sense a variety of things. So a detector is just a common name for advice that senses things. In this case, we're talking about smoke. So what are the ways in which you can detect smoke or what are the different detection? Methods?

Detector is defined as a device suitable for connection to a circuit that has a sensor that responds to a physical stimulus. Such as gas, heat, or smoke. In addition to the types of detectors, there are a variety of different device configurations or means and methods in which you can use technology to, uh, detect certain fire phenomenon or hazardous conditions.

There are single spot type detectors, which is probably what most people think of when you hear smoke detector. A common misconception is that a smoke detector is not the same thing as a smoke alarm frequently. When you'll be talking to people who aren't in fire and life safety as a discipline, they will use these terms interchangeably and they certainly are not interchangeable.

A smoke alarm is defined as a single or multiple station alarm responsive to smoke. That doesn't help a lot with how to caveat the difference between smoke detectors and smoke. Alarms smoke alarms are generally a single device that annunciates and detects smoke all in one piece of equipment. And so what you have inside your home, if you live inside a house or oftentimes in apartments as well is smoke alarm.

Put very simply a smoke alarm detects smoke and provides notification in the form of a alarm tone and a smoke detector is strictly used for sensing the. Criteria that you're looking for. So that could be heat flames. Uh Gasier. So that is the difference between smoke detector and smoke alarm. I can't think of a case in which a smoke alarm would not be used in a residential type occupancy.

So particularly in sleeping rooms, dwelling units, single and multiple family dwelling units or homes. These are all common places which would have smoke alarm requirements within the code, or would allow you to use. Smoke alarms in lieu of smoke detectors for commercial properties that are code required to have fire alarm control units and fire alarm systems.

Generally you would use smoke detectors. It's important to understand the difference between smoke alarms and smoke detectors. There will be times where these two terms will be conflated and you will have to determine what is code required and then Institute that device type. Speaking of code requirements.

Let's talk about where in the international family of codes that discusses smoke detectors and what kind of requirements you might find in this code exce. Requirements for smoke detectors can be found in the international building code, which is largely the document that is adopted throughout the United States, um, to varying degrees with amendments.

And so let's look at section 9 0 7, which is titled fire alarm and detection systems in the building code. Chapter nine is. Fire protection and life safety systems. And then we are in section 9 0 7 again, which is fire alarm and detection systems. Similarly to how you would find out if you have a requirement in your facility for a sprinkler system.

Now, now seven in the building code is where you would go to determine if you are required for your facility to be equipped with a fire alarm system. We've talked about this process before, but essentially you have to analyze all the salient qualities of fire and life safety in your building. And see if you hit any of the thresholds within this chapter or within the rest of the building code or fire code.

This sounds like a daunting task, but in time you will know which of these common triggers generally indicate their requirement for a fire alarm system. On the topic of smoke detectors, there is specific language in chapter 9 0 7 for when some smoke detectors are required. Not all of the different situations that might cry require a smoke detector are located in chapter 9 0 7.

But a fair number of them are. And it also talks about smoke alarms as well, even though that's not specifically the discussion of this solo cast, uh, I will talk about smoke alarms in the future. It's a great topic and very common topic like previously stated. There are a number of areas in section 9 0 7, as well as chapter nine, in which location requirements for smoke detectors are state.

In addition to the code requirements of section 9 0 7 in the international building code chapter 17 of NFPA 72 titled initiating devices has the requirements for general usage of smoke detectors and specifically spacing criteria. Other considerations for the installation and design of smoke detectors.

There are multiple different types of. Coverage approaches or protection approaches when using smoke detectors, there are two big types which are total or complete coverage, or sometimes commonly referred to as area coverage. And this is smoke detectors and a detection system located. Throughout an entire facility, and then there is partial or selected selective coverage.

And this is commonly referred to as specific hazard. Protection. So an example of total coverage or complete coverage would be providing spot type smoke detectors throughout a facility. One instance in which you might have total coverage requirement in the code based on the international building code.

Is, if you have a requirement for a duct detector in your facility and you cannot locate a duct detector inside the unit. So if you want some more information on duct detectors, I believe that was our first solo cast episode, but suffice to say. That is one of the ways that can trigger total or complete coverage within a facility, an owner can elect to provide total coverage as a risk reduction option for their facility, but it is not explicitly required in the code in a lot of places.

More commonly you will see. Partial or selected selective coverage, specific hazard protection with smoke detectors. So you can think of the smoke detector at a fire alarm panel or outside of an elevator door or fire door as an example of. Partial or selective coverage. The theory behind each of these approaches is you are protecting a specific hazard and you're interested in smoke production of a specific piece of equipment or to trigger a specific function in the case of a fire for.

Specific hazard approach or partial coverage and total or complete coverage is to broadly sense if there is any smoke within the facility to either trigger the, uh, alarm and shut down of the air handling unit or to give the occupants a chance to have. Faster notification of fire within the facility.

Let's talk about the different types of smoke detector. A little bit. I made it a short list of about six different types of smoke detectors, and I'm sure there are more that. Maybe I'm even not aware of, but so far on this list, I have duct detector, which is a spot type smoke detector that is listed for in use in ducts 2 cents smoke.

And then there are aspirating smoke detectors. Think of a system. That is used for very early warning fire protection and uses a piping tubing system and a fan in order to sense the very incipient phases of combustion spot type detectors. For smoke, laser smoke detectors. There are ionization smoke detectors detectors, which, uh, photo electric and ionization are two different types of spot smoke detector.

And some detectors will use a combination of these methods in order to create a better possibility of eliminating nuisance or false alarms. Also, there are beam type smoke detectors, and I don't see these used as often, but they are sometimes used commonly for big atriums or large facilities that it may be difficult to house.

Smoke detectors on. I've seen them in malls. I've seen them in big atriums. And so that is a common usage for beam detectors that is gonna do it for this episode about smoke detectors. Hope you enjoyed it. Thanks for listening. And we will see you next time. Thanks for listening. Everybody. Be sure to share the episode with a friend, if you enjoyed it, don't forget that fire protection and life safety is serious business.

The views and opinions expressed on this podcast are by no means a professional consultation or a codes and standards interpretation. Be sure to contact a licensed professional. If you are getting involved with fire protection and or life. Thanks again, and we'll see you next time.