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Components of an ERRCS System

Posted by ORR Protection on Jan 22, 2021 10:00:00 AM

During the MCFP Virtual Conference series, Dal Brazzell, Sales Manager at ORR Protection Systems, discusses Radio (BDA) Systems. Part 3 of 3.

Radio (BDA) Systems

Video Transcript:

And this is a typical example of a, of a system layout, but what you'll notice here. So in this, in this example, the fire department is using UHF, or excuse me, VHF the police departments using UHF. And you'll notice here, we have two donor antennas on the roof in addition to two BDAs in the building. So they share the same dads are distributed antenna system within the building, but you do have to have one amplifier for your UHF and one amplifier for your VHF, or it could be one for UHF and 700 megahertz, but each of those is going to have its own amplifier and its own roof mounted antenna. And that's key to know, because if you're in a jurisdiction where you have multiple bands being used these are high value pieces of equipment. And the cost cost of the project is going to go up dramatically.

If you have to install multiple things. So from a design standpoint, again, they're highly engineered systems. So once the contract is awarded to the sub, the sub is going to go in and take, do initial site surveys to make sure the reading within the building. And again, a cinder block walls are going to filter out more or less, then a solid wall or a sheet rock, and two by four stud wall and, and different types of glass and brick are gonna filter out things. So you have to know the exterior building construction materials, the interior building, construction materials, the total number of walls that the radio frequency has to penetrate. Total, obviously the total square footage of the building. And then we do, what's called an IB wave model of the building. And within this IB wave model of the building, it's going to know based on the outside signal strength that's currently available at the building where the, where the dead spots are.

And then obviously our goal here is to fill in those dead spots with the distributed antenna systems within the building. Normally speaking, you're going to get probably 6,000 to 7,000 square feet of coverage within a typical building out of a distributed antenna out of one single antenna. So if you needed really 100% coverage in a building, you'd normally figure you'd have to have the total square footage divided by six or 7,000 square feet. And that gives you the number of the number of antennas that you're going to need. And obviously that's going to tie back into the, to the BDA, if you have a large building, like a high rise or a horizontal high rise, large manufacturing or industrial facility again, if you have a high number of antennas and a lot of coaxial cable and splitters, you may actually have to have multiple amplifiers in order to get that signal strength at the antenna location.

So we would do this IB wave modeling and that we're going to get that information through the initial site surveys. We have to pull a permit and the permit on the, on the emergency responder radio communication system is going to differ from the permit. We would pull for a fire alarm or fire suppression system. And again, the permit holder has to, has to have an FCC license. We're going to have several points where we're going to need a 120 volt AC power because obviously the amplifier enclosure needs 120 volt in our battery backup. So this system has to have, it has to be battery backed up just like a fire alarm panel. It has to be in a NEMA rated enclosure, a watertight enclosure. It has to be monitored by the fire alarm system. It has to be in a two hour rated space, the, the head end unit.

So there's a lot of survivability requirements. So we would need a 120 volts for that for the actual BDA, 120 volts for the power supply and the battery charger. And then obviously this thing needs to be grounded fairly well because you've got roof mounted antennas, which is going to be a lightening potential lightening rod. So we would normally then have to install the coaxial cable and the coaxial cable is not the standard co-ax that you would get from a home Depot. And Lowe's, this is a half inch corrugated air dielectric co-ax, and it's very similar to half inch corrugated conduit. So it's really stiff. It's got an aluminum outer corrugated jacket, and it's got a solid copper conductor in the center. That's going to be separated with with a silicone washer or a standoff. And you can't obviously have any breaks in the outer aluminum jacket, and you can't have any shorts between the copper and the aluminum.

So you have to be really, really delicate and careful with the with the co-ax when you're pulling that. Now, normally there, there is plenum rated cable available. So if you're in a building that doesn't require a pathway survivability level two or three it is possible to where plenum rated cable is permitted. You can install plenum rated cable without putting the cable and conduit where you have to have pathway survivability level one. You would need to put that coaxial cable within conduit, and because of the size of the con of the co-ax cable, you normally would need two inch conduit and terminal boxes, whenever you have to make a connection. So it can get pretty expensive on the on the electrical side for the folks that are putting in the raceways, then we obviously would install the connectors.

So we would need to install the Yagi antenna on the roof coordinate with the roofing contractor to make sure that that we don't have any issues with penetrating the roof membrane. And normally that would be by others. We would also need to pull up circuit from the BDA head end, the fire alarm command, or the fire command center a remote annunciator, that's going to be an eight conductor cable. We're going to pull our circuit from the BDA to the fire alarm SLC, where we're going to need six monitor modules to monitor the six trouble signals off of the the head end equipment, obviously mountain terminate, the devices handle the core drilling, fire seal, fire stop, and then test and optimize the system. And there's quite a bit of work that needs to be done on the, on the final survey and the the test and start up here.

And again, you know, grounding is, is, is really key here of the system. So final installation is really not all that complex. The, the, the most complex part of this is going to be the, the survey on the front end and the survey on the back end. And you'll notice here that you've got signal strength. In this case, we can see the black dots are all of our inside Daz antennas. And the red coloring is where we've got high signal strength. And as you get further out into the blues and blacks, that's where you've got lower signal strength, but you can see the key here. We keep the signal inside of the building. And that's one of the key items is you really, you can't broadcast signal from inside back outside, or you can end up having isolation issues and oscillation if your outdoor antenna is receiving a signal from its own indoor antenna.

So you've gotta really be careful not to over amplify the system, which has happened in some systems and created issues for citywide, countywide AHJs and taking, actually taking the entire systems down. So lessons learned things that are, you know, we really want to communicate to the architect engineering contracting community is because this is a relatively new system. There's still not a lot of manufacturers out on the market. And you're going to find that there are a lot of opportunistic manufacturers trying to jump in this space because they see, they see the the demand created by, by the code requirements for these systems. And that's, that's really important to know because you can buy a lot of systems that haven't been tested by UL. And you really don't know if you're getting a quality system that's going to survive.

You know, people are literally buying parts and pieces online from Amazon and putting systems in I've seen amplifiers that are installed where the power for the amplifier is literally just a wall wart plugged into the wall socket. So anybody can come and just unplug the thing and take the entire system down that obviously would not pass you well. But we see a lot of manufacturers out there and a lot of specifications out there for non UL listed systems. And there are several manufacturers now that are, that are making UL 25, 24 listed emergency responder radio communication systems specifically for, for life safety use. The other one of the other challenges we really run into here is a lack of two hour rated vertical pathways for the riser and backbone. This is key pathway survivability level two or three definitely has an impact on a fire alarm system when you're having to upgrade from standard fire alarm cable to circuit integrity cable.

But when you upgrade from, for a long time, there was no two hour rated coaxial cable, but now there are some manufacturers in the market that do have ULS two hour rated coaxial cable, but that cable goes from several dollars a foot to over a hundred dollars per year. So there's a drastic increase in the price. If you have to accomplish your, your two hour pathway level two or three through the use of circuit integrity cable. So it makes a lot more sense to have, and particularly a high rise application or an any building where you've got a two hour rating for the building, and you need to meet that pathway level two or three for the, for the emergency responders system to have stack two hour rated electrical rooms or MDF rooms where you can run your circuits and protect the circuits within the two hour rated space and not have to run special cabling.

You know, it's important for us to know as a contractor from the engineer, what those pathways survivability requirements are. A lot of times when we see control construction documents or specifications, we don't see any reference to the pathway survivability requirements. We're not seeing the building fire ratings, or we're not sometimes given that information. We don't know the location of rated walls and rooms within the space. And that's just not given to us in our construction documents. It was key to it, key to provide that. And the probably the most critical element here is to when a specification goes up for a building. We prefer obviously on the engineering side, the engineers coordinate with the local AHJs and ask for their specifications. So most cities and most counties are going to have an individual that's responsible for the county-wide radio system, and they already have specifications available in the market.

Just pick up the phone and make a phone call, and they'll be able to give you a nice spec and I'll tell you exactly what frequencies and what bands you need to amplify and what the performance requirements are in their jurisdiction. So from a contractor standpoint, this is probably the biggest thing that we see is it's a system that's typically overlooked. It's not included in the specifications of the construction documents. And the fire department shows up at the building. They walk in the building, their radius signals die. And obviously they hold up the certificate of occupancy and it becomes a last minute panic by for the general contractor or the electrical contractor. And obviously when you're buying something last minute from a panic standpoint you're, you're not, you're not getting your best price. And the cost of installation after after ceilings are up and walls are up it's a lot harder to rough in a conduit and cabling and and put the system in for the best price.

We also struggle with difficulty coordinating between multiple trades. So again, we're having to interface this into the fire alarm system. We're having to get electrical and here, and we're having to coordinate with the roofing contractor. And from an ownership standpoint emergency respond to radio communication systems. Once they're installed, there are several things you have to be aware of. So it is a life safety system. And as a life safety system, it has to be serviced annually pertinent PA and if jurisdiction changes frequencies from one frequency to another, or one band from another, that system has to be upgraded every year, if, if they upgrade or they change frequency. Yeah. So that they've got a functional radio system within the building. And then every flight five years, you have to do a system recertification or a coverage recertification.

And this is to verify that you still have that minimum amount of coverage and bill and every space of the building to meet code. And even if you don't, if you didn't install an emergency responder radio coverage system at the beginning of the project it's possible that his other buildings you know, may build one building in a Metro environment and then other buildings get built around you. And as those buildings obstruct the signal, you may not where you had signal in the building before you may not have signal later. So every five years the building owner has to hire somebody to come out and do a recertification and tell you if you need a system. And obviously you have to install a system at that point in summary, emergency responder radio communication systems. They do provide additional capabilities over traditional hardware, hardwired systems.

Nobody really prefers the use of a hard wired telephone system anymore. And hard-wired firefighters phones are of no use to the EMS or the police department and those type of emergencies. These systems can be very expensive to install and support particularly if they're not designed properly on the front end or if they're not installed properly on the front end. And you want to make sure that you provide a contractor that at a minimum has access to a UL listed product and obviously has their FCC GRL license and have some experience in the market. Just want to thank you for your time and attention. And if you have any further questions about emergency responder radio communication systems, where you want to dig a little deeper, feel free to reach out to org, and we look forward to working with you. Thanks.

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