May 3, 2021

Welcome to solocast episode 6 of Fire Code Tech. On this episode we are talking about sprinkler systems 101. I wanted to start to break into sprinkler systems and start at the extreme fundamentals. If you enjoyed this episode don’t forget to go check out the extra episode on patreon.com/firecodetech

https://firesystems.net/2018/09/07/types-of-sprinkler-heads/

https://www.youtube.com/watch?v=o-ylvugYc0w

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. Welcome to episode six of the solo casts of fire code tech. In this episode, we're talking about sprinkler basics. So I wanted to intro the conversation about sprinklers and really start diving into this technology. But. Before I take a look at the codes and standards and really go full bore on how to determine when these systems are needed and how to install them.

I wanted to talk about some of the system essentials or the extreme basics. I know this is gonna be two elementary for some of my listeners, probably a large portion. But I think it is important to have a rock solid understanding of the foundations of sprinkler systems. And maybe this will be informative for those who don't have a strong of a fire suppression background to start off with the standard for installation for sprinklers is N FPA 13.

So in the us, and in a lot of other parts of the world, Uh, NFP eight 13 is the standard document to determine the installation features and design requirements for a sprinkler system. Now, this doesn't tell you when these systems are required. And so I'm not gonna go into that for this episode as something that I will dive into further, um, at a later date.

But this is going to be more about, um, system component, basics and architecture and features of, um, fire sprinkler system components. So, yeah, that's kind of a preface for some of the content you're gonna hear about. In NFPA 13 is the national fire protection agency's standard for the installation of sprinkler systems.

So I realized, I didn't say that still. So, so in order to give us a basis or, uh, rock solid, fundamental, uh, base, I wanted to start with some definitions about a sprinkler system and what that. Let's take a look at 3.3 0.205, sprinkler definitions more specifically, the first definition in this category titled automatic sprinkler.

This definition says a fire suppression or control device that operates automatically when it's heat activated. Then it goes on to say the element is heated to its thermal rating or above allowing water to discharge over a specified area. So this is talking about the fundamental characteristics of a sprinkler and what we need to have in order to consider something a sprinkler.

I'm gonna plan to include a, a picture in the show notes, but the general characteristics of a sprinkler are, um, a deflector, uh, some sort of element to, to fuse or to break at a specified heated. Temperature. And then also, uh, a frame, if you will, there are a couple different types of sprinkler head, fundamental types.

So there's many subcategories within these types, but, um, I would say the main three categories are upright pendant and sidewalk. These all refer to the orientation in which the sprinkler is installed. And so when we take a look at the orientation in which they're installed, you have to, uh, there's easy ways to determine if the sprinkler is one of these types by visually inspecting it due to the shape and configuration of the deflector, which is the top piece of the sprinkler.

So. Upright sprinklers will generally have a curved deflector in order to ricochet the water off of the deflector piece and redirect it. Um, downwards, um, pendant sprinklers will. Uh, usually have a flat deflector because, um, of the dispersion pattern meant to deflect it downwards and side wall sprinklers typically have a, um, a like L shape looking deflector.

So this is ordered to, um, kind of flatten the spray pattern out and to project it forward. And so I'll try to include some pictures in the show notes, but I just wanted to cover this, um, first and foremost. And so. There's a couple different things that you can tell just by looking at a sprinkler. Um, generally there, if you want to determine, uh, so the hole in which the water comes out of a sprinkler head, It's called the orifice and the orifice there's standard orifice sizes.

Um, the most common is 5.6 K factor. So what does that mean? Why would you want to know when you have, uh, a certain size of orifice? Well, the size of the orifice and the pressure at which the, um, sprinkler is activat. Determines how much water is released when the sprinkler is activated. And so there's a simple formula for determining the amount of flow that a sprinkler releases, um, when activated, by knowing these factors.

And so the K factors range from, um, much smaller than 5.6, the residential sprinklers are, uh, I believe in the, the four range. And then if you look at. Specific application storage, sprinklers. Um, they can go all the way up to 25.2 K factor. So what does that mean? Let's do a quick little exercise to determine, um, at standard pressures, what kind of water release that would be.

So if we are determining flow, the equation that we. Is the K factor formula. And this is Q equals K times the square root of P pressure. So I did a little bit of back of the envelope calculations to take a look at what, uh, standard sprinkler at a 5.6 K factor with the minimum operating pressure of seven pounds per square inch seven PS.

And what kind of flow would that release? So it's important to kind of have these back of, um, you know, these understandings of standard flow for when you're taking a look at preliminary hydraulic analysis. And so, uh, the formula we we spoke about previously was K equals, I mean, Q equals K times the square root of P.

So if you take 5.6 K. And then you multiply that by the square root of. You get 14.8 GPM or approximately 15 GPM. So this is the, the standard amount of water that you could expect out of. Uh, one of the most common types of sprinkler heads available the 5.6 K factor head. And so then I took a look at a 25.2 K factor head, which is one of the largest that I'm.

I took a look at a 25.2 K ESFR head, a Viking head. And then I took a look at a cut sheet. Couldn't find a minimum available working pressure on a cut sheet. It said to refer to N F P 13, took a look at N F P 13 and took a look at a storage application for, uh, ESFR sprinkler head at about. 25 25 0.2 K factor.

And so the minimum, uh, working pressure of the head in the ESFR scenario for this example was 15 PSI. So I took 25.2 and I multiplied the square root of 15. And then I got approximately 98 GP. . And so the physical size of these sprinklers don't change, um, that drastically, and you can see that we've over quadrupled, the amount of water coming out of this sprinkler head.

So from 15 GPM to almost a hundred GPM, and this is, uh, 15 PSI is low on the. Pressures that, uh, 25.2 K factor head could operate at, could operate at, um, 60 PSI or maybe more if there were other applications I'm not exhausted exhaustively looking at these, um, pressure applications. So they could have, uh, quite a lot of water coming out of one of these sprinkler devices.

So here's the definition of the sprinkler system in, in FPA 13. We wanna talk about this because it goes over the fundamental architecture pieces of the sprinkler system here is a good basis, uh, for everybody to know. And in fact, I can't tell you how many times that I've gone back and read this, not too many sprinkler system 3.3 0.206.

I'm looking at the 2019 edition of an FPA 13. It says a system commonly activated by. From a fire and discharges water over the fire area that consists of an integrated network of piping designed in accordance with fire protection engineering standards and includes a water supply source, a water control valve, a water alarm water flow alarm, and drain.

the portion of the sprinkler system above ground is a network of specifically sized or hydraulically designed piping installed in a building structure or area generally overhead, and to which sprinklers are attached in a systematic pattern. Wow. That is dense. So let's go over a couple of these specific parts so I can expand upon 'em cuz they're, uh, multifaceted.

It says a system commonly activated by heat from a fire and discharges water over the fire area. So this rings up a situation in which I didn't even think about is you have, uh, so you have systems, fire suppression systems that are manually activated. Like, uh, the, the ones that I can think of would be, uh, Um, I'm sure there are pre-action systems that can be, uh, manually activated or, uh, you know, uh, a daily system could be manually activated.

And so that's an interesting caveat with that statement says, next sentence says. that consists of integrated network of piping design in accordance with fire protection engineering standards. That includes a water supply source, a water control valve, a water flow alarm, and a drain. So here they just, they just told you the, the fundamental pieces for what you need to call in a sprinkler.

Um, uh, water supply. So if you have no water to put into the system, uh, you, you can't have a sprinkler system. And so I want to dive into water supply analysis, but yeah, really, we're just going over the definitions here, a control valve. So a control valve is basically a way to. Isolate the system, uh, provide maintenance or to do work on the system.

And then they say a water flow alarm, which is a way to know when the system is activated. So for, uh, standard web pipe systems, this would be a vein type water flow switch, which is essentially a paddle within the fire suppression piping that is moved by the flowing of water and then sends a signal to the fire alarm panel.

or a pressure switch in the case of a dry pipe or a pre-action system. And then it says a drain. And so you have to have a way to get the water out of the system. If you need to maintain it, if there was a, uh, false activation, um, in the case of dry action or pre-action, you need to drain it for maintenance purposes.

So you have to have a drain. Something I think is interesting is they don't talk about backflow prevention, which. Is, and is not a component of a sprinkler system, I suppose. Um, you need one, you need one when you have a sprinkler system, but the physical sprinkler system. Is, uh, like they said, a control valve water flow alarm, a way to drain it and water to supply the system.

So it says the portion of the sprinkler system above ground is network of specifically size and hydraulically designed piping installed in a building structure or area generally overhead. To which sprinklers are attached in a systematic pattern. So here they referenced the hydraulic calculation method, as well as the pipe schedule method.

It says that there is intentional sizing to these pipes. So I've really just breached the surface on what a sprinkler system is. And if you can't tell for quick, A sprinkler system is a combination of valves, piping drains, and alarm devices that is utilized to put out a fire. And so there are a variety of situations in which these systems are required by, um, code for whatever jurisdiction you're working in.

And so, uh, really, I just wanted to cover some of the very essentials, um, on this topic. And I want to keep diving into the topic of what these systems are, their component architecture, and, uh, really just keep going on this topic. I. I didn't get, as far as I thought I would on this first episode. But, um, I think that just goes to show how deep the topic is and, and how broad it is.

Um, yeah, and I think I went on a tangent there about the, the K factor in the orifice and how much water you can flow. But I think that's interesting and important as well. So hope you enjoyed this solo cast and if you wanna check. Another, um, episode of similar length about sprinklers. You can go check out the Patreon at patreon.com/fire code tech, and, uh, hear another episode about sprinklers that's re released right now.

So go check it out. 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 safety. Thanks again. And we'll see you next time.