Applying PRVs in Plumbing Systems

the broadcast is now starting all attendees are in listen-only mode hello everyone and thanks for attending today's coffee with Coletti webinar this is kevin free located here at the colossi north america headquarters in beautiful Milwaukee Wisconsin today we're honored to have a very special guest speaker Julius Polanco Julius is a graduate of Stevens Institute of Technology he's a registered professional engineer and a licensed master plumber as well he is president of JB engineering and code consulting PC and his firm specializes in codes and standards consulting in the areas of plumbing mechanical life safety and fire protection engineering Julius is a well-known lecturer and a monthly columnist in both plumbing and mechanical and p.m. engineer magazines so welcome Julius well thank you and good morning or good afternoon depending on where you are in the world today I get to speak on one of my favorite subject matters which is pressure reducing valves I always been fascinated by the use of these valves they're kind of a simple valve I'm always asked how do they work and what are they doing it's just a easy way for us to control the pressure in a in this particular case of plumbing system I and I've been often accused of saying the valve is a dumb valve or a stupid valve actually they're very smart when we design them correctly and set them up properly but in the way they're done they will do whatever you tell them to do they are designed to control the pressure so let's go into first how they work they're nothing more than in a way a glorified check valve that's got a tension on the end where we need to apply that pressure to open the orifice and let the water flow and in doing so we are lowering the pressure I had a college professor that in fluid dynamics that always said when you're confused influence which media so instead of talking about water what we're now let's talk about air I in the air quite a bit flying around this great country of ours and when I hop on a plane in Chicago and go to New York the pilot gets on says we have a good tailwind and we'll get to New York in an hour in 20 minutes when I turn around to come back home I hop in the plane and the pilot gets on and says we have a tremendous head wound and it takes an hour and 40 minutes well the plane has gone the same speed nets the pressure and what's happening is that headwind is now slowing the plane down so it takes all the sudden 20 minutes longer to get home that's what's happening with our PRV is we are putting a headwind in and slowing down that pressure so if we take a look at it let's do an inlet pressure of 150 psi so that pressure is coming in now I've got a spring and a diaphragm that's working on that orphis and that is holding the office closed but the the pressure is going to want to open it up and the tension that I'm putting on it is 70 psi to open that up so I'm I'm exerting I'm using 70 psi of energy you know pressures energy so to open it and the end result I take 50 150 minus 70 I end up with 80 psi so on on the outlet of my PRV is 80 psi so that's the simple basic way of how our pRb is going to operate it's just I would like to look at it as an energy conversion or energy is 150 psi it takes a 70 psi of energy to open the valve and as a result I'm only left with 80 psi and it's how these valves are going to operate that's how they function of course we have to keep in mind that it is a valve and the more flow we put through it the more restriction we have and we have a CV factor and we're going to talk about later on and that CV factor is going to also change our pressure dynamics so we can't forget that aspect so we have two aspects of the valve one is the opening and closing which is still under pressure the other is the movement of flow through the orifice and that's kind of steel pressure so let's make sure we remember both of those the mistake I find both from my engineering colleagues and my contractor friends are they forget about the second factor the CV and they just think this valve is stupid and if I said it it's going to go to 80 psi I'd always be 80 psi when I run a lot of front water through there the pressure is going to drop below my 80 psi keep that in mind we'll talk about that in just a bit let's look at this also we get into a larger valve and I throw a simple diagram this is nothing more than diagrammatic where I throw a pilot line in and you can have a pilot line on the inlet pressure going up to the upper chamber of the diaphragm and you can have a pilot line on the downstream pressure that goes into the upper chamber of the diaphragm they're going to be controls on those pilot lines now basically in simple terms what the pilot lines are designed to do is to offer better and smoother controls to the PRV so the pressure reducing valve tends to want to open up and enclose and what a pile line is going to do is going to slow the opening it's going to slow the closing it's going to fine-tune the setting of the PRB so you you get into a large valve pilot lines too many of us in the engineering profession or a must you technically don't need them but they do allow the valve to operate smoother and better and perform much better in the field so start to think in terms when you you're getting up I always say once you're getting up over a you know two inches you could have a fine line a two inch but once you're getting over that I like to have pilot lines and better control of my PRV so let's take a look at all the different types it was showing some of the different products you have out on the marketplace the smaller valves right there in the middle is my big guy and you notice I've got a pilot line on the inlet and I'll outline on the outlet of that particular valve and that's going to give me the control and in the middle of the pie outlines of course is going to be a PRV of pressure reducing valve and that's how I am going to set the valve so a lot of fine-tuning goes in I always tell contractors you're worth your weight in salt if you can fine-tune these and set up the pilot lines properly nowadays I find a lot of contractors on large high-rise buildings are turning this all over to a balancing contractor and that's fine you know whether you do it or balancing contract to make sure they're set up properly once they're installed let's look at the sizing and selecting of pRb when we get into it there are certain factors that must be considered and some of these are often overlooked and I want to make sure we cover them all first of all we have to look at the maximum Inlet pressure I had a project that I went into and they they were trying to lower the pressure down from 300 psi to a lower pressure say 150 PS on and they put a valve in and that valve when you read the literature said its maximum pressure was 150 psi and it lured to the lowest pressure was 30 well that was the wrong valve to select so we have to look at what is the maximum Inlet pressure that the valve is set up for and then next is what is the minimum outlet pressure sometimes about won't go down to the pressure rating that I want I was dealing with one mouth contractor install that pulled out the manual on us and it said the lowest outlet pressure was 75 psi we're trying to get it to 60 well you're never going to do that so again we've got to look at those factors in our design before we install them out next thing we get into is the maximum flow rate the maximum flow rate is going to be what that valves maximum capabilities are most valve manufacturers are also going to tell you what they consider to be the sweet spot or the range that they want you to design your system for in the maximum flow-rate now the Bowser will go above that but when you go above the sweet spot you start to lose more pressure during that particular flow and it becomes a more erratic pressure in the piping system so you try and look and we'll talk about the sweet spot in a second the other one you get into is the minimum flow rate this is an often overlooked area it's often overlooked by my engineering colleagues and it's often misunderstood by some of my plumbing colleagues and my contractors they tend to think well you know I got the bow then well it'll operated anything and I mentioned that in the middle of the night if I'm in a multi-story building and somebody gets up at 3 a.m. and flushes a water closet well that's only gonna use one point six gallons and it fills in 35 to 40 seconds so we're looking at a 2 GPM flow rate and you've got these large valves they don't want to open for just two GPM so we're gonna have to look at what the minimum flow rate is and then finally another important factor is the maximum temperature a lot of times we have contractors that think I'm just going to put one of these at the start of the building well I'm putting them throughout the building and if I'm dealing on hot water piping system it better be rated for the temperature in my hot water some valves are rated only 140 degrees Fahrenheit others are rated 200 maybe some go over 200 degrees Fahrenheit so you've got to know what you're dealing with if we get into a commercial kitchen area I'm typically running 180 degree hot water if I get into a residential commercial type building I'm typically never running over 140 so I have to look at these factors and then finally the two warnings that I throw out there one we've just been talking about don't forget the minimum flow rate that is as important as the maximum flow rate don't ignore it look at what the manufacturers identify as the minimum flow rate and don't try and set up a system that goes below that what that means is sometimes we're going to put in multiple valves to supply the same system and we'll talk about that in a little bit and then finally don't forget about the valve cv a lot of manufacturers are not gonna give you the CV directly some do I use the chart and we'll show you how to use the chart in just a second here so the the CV is means that the more I flow through that valve the more pressure I lose so even though I have it set at one pressure I'm going to get a lower pressure when I'm flowing that amount of water let's look at what we get in a specification sheet for manufacturer manufacturer is going to give you a specification sheet I stole a collection here and then this particular one the information you're going to look at let me blow it up for you its first of all it's saying this PRV is suitable for water we're going to talk more about what's required to get that certification and event and then you see the maximum working pressure for this particular valve is 300 psi so I can handle some high pressures the downstream pressure settings it will only range it from 15 to 90 so if I got to go 150 this is the wrong Val I'm not going to select it and I'm often asked why would I only go down to 150 I might be using it for industrial applications you know I got a potable water supply to an industrial process or I might go to a piece of equipment or maybe to a lawn sprinkler system something to that extent so we got to know what our ranges are and this one is typically in the plumbing ranges these are ranges for plumbing fixtures and then the factory setting this one coming out of factory is set for 45 psi now you can set it in the field to anywhere from 15 to 90 but the factory setting is going to come at 45 then finally the maximum working temperature you notice this one is good to a hundred and eighty degrees and then finally if you notice this one had a pressure gauge installed directly on the valve and that pressure gauge reads from zero to 100 psi now let's go into the chart that the again for this particular valve that the manufacturer provides for sizing it's a real simple chart and if you see that blue area that blue area is what the manufacturer identifies as the recommended or what we engineers call the sweet spot that is the range that this valve prefers to operate in so if you're looking at the peak demand the the typical maximum flow rate we want to be in this blue range now you'll notice for this particular one I took a system that is flowing under pictum an 8 GPM you go up from the 8 and you follow it up to the line and you get into that sweet spot for 3/4 inch valve and you come over and you see that the velocity is running you know just under 4 feet per second so this particular valve the 3/4 is the ideal one for the a GPM now interesting if I'm gonna run let's say 20 no whoo when the right mind puts 20 GPM for 3/4 let's just say you did you could bring this up and that bad will still operate you know you're gonna have some high velocities there which means we're going to have higher pressure losses through there but the valve will still perform so what we're looking at really is the the sweet spot in these particular valves this chart that we're looking at right now is not going to show us the diluent remember the low end I said you it only can float a certain velocity that's going to be our next chart we'll take a look at but so this one is showing us how could how can we thaw is based on our flow rate and getting into that sweet spot let's go to our next nomograph and on this particular nomograph this is showing you the fall-off pressure this is taken the cv for the valve you know which is our our constant factor for the orphis going through the valve and it's looking at the flow rate and you know all my engineering colleagues remember that the CV and the pressure drop is related to the square of the flow rate and the square of the CV so that's how we get our pressure fall-off and in this particular valve I say the square of the CBI meant to square the flow rate my apologies so in this particular valve we took in the a GPM for the three quarter inch and if we run up from eight hit our three quarter-inch value see our three quarter inch coming down here on the curve it says I have an additional pressure loss of 7.3 psi so let's say I left that Valve at the factory setting a 45 psi if I'm flowing eight GPM I'm not getting 45 psi downstream I'm getting 45 psi minus my seven point three so I'm really down around let me see if I do my math quickly like thirty seven point seven did I do it right somewhere in that range psi so I if I'm looking for 45 psi at that flow rate I'm going to have to increase the pressure setting of the valve to accommodate that so that's part of the setup this is this is a mistake made by both engineers and contractors in the field where they think once they set the valve that that's where it's going to be all the time and that's not true so really what I have to do is I have to set the valve and account for the pressure that I'm going to lose going through the orifice of that valve and I've got to take that into consideration when I'm adjusting my system before I you know during the commissioning process so just keep that in mind now what you don't see this particular nomograph is only going up to an inch and quarter valve most valves inch and a quarter sometimes up to as much as inch and a half you can go down to a pressure or a flow rate I should say of like zero just above zero in other words the valves going to operate it'll open it doesn't have a problem if we have a two inch valve it might come down to this point where it's like 20 GPM and the line might end there so that it'll run up here and of course you know we'd have to change the scale to see how much more flow rate we get with that pal but and I just made up the 20 I'm just giving you a number as an example but let's say that two inch valve says I'm gonna range from 20 GPM to X GPM well that means if if I'm less than 20 I've got to do something so that's where we start to put in two valves in parallel and we'll talk about that in a little bit but just realize that's where I'm looking at the larger valves when I get into a larger valve they're not going to operate all the way down to zero psi zero GPM what you want to do with the valve is I always say if you don't design the system correctly the valve starts to fight it wants to open a can hope and it wants to open a can open it and it's when you're fighting you're slamming that valve you're pounding it and you're beating the living daylights out of it and that's going to cause a premature failure of the valve so that's that's what we want to so we're always going to look to try and get them out into the sweet spot and out of the low-end range where the valve is going to operate on the low end so just recall that when we're looking at the overall design when we get into these factors Julius yeah this is Mark I'm going to interrupt with a question we just want to come in related to this is this a good point to make that it's dangerous to size a pressure reducing valve based on line size it actually hits and when we were going over this I mentioned that but the one thing that the mistake that's often made is engineers will say well I've got a two-inch lines all put in a two PRV maybe maybe not maybe I need a 2 and a half maybe I need an inch and a half on that particular line so I have to look at what the performance is of the valve and what I'm trying to accomplish so the common mistake made is I've got this pipe size therefore it equates to this valve size don't fall into that trap look at the performance of the valve look at the design of the system of what the flow rate is and also look at the pressure fall-off try to be in the sweet spot under the peak demand and make sure you meet the low end factor so that at a very minimal use of water the valve will operate or the valves when we're talking multiple valves excuse me all right let's go into this 2 valve concept what we call the high-low the high-low is for when we have larger flow conditions and normally larger pipe size I mentioned typically larger than inch and a half to inch in size all right so for these higher flow installations we're going to put in 2 or maybe 3 P RVs that are going to be installed in parallel I happen to be one that likes as an engineer I like designing with two I was just on a project out on the west coast where they use 3p are these nothing wrong with it that was just the control that that engineer looked for he was trying to get into three different sweet spots and also provide for very low flow condition again somebody getting up in a dwelling unit in the middle of the night 3:00 a.m. and flushing the water closet maybe turning on the laboratory to wash their hands so that's why they went with the three as you can imagine if it's three it's normally a residential building commercial buildings I will typically always get away with two but again that's me I'm not going to say any engineer is wrong for designing three or any contractor just try and get within those design features now the smaller valve is always going to handle that low flow condition when the water uses minimal and as soon as it gets up above the sweet spot for the low valve we want the larger valve to take over and then that larger valve is going to handle the peak demand and not that high flow rate condition right and normally the low valve is not going to be doing much of anything at all now when setting these up the mistake contractors and engineers will often make is they'll you know say to set the valves when they're in parallel like this to send them at the same pressure setting well that's not going to work as now the valves are fighting with one another typically what we will do is take the smaller valve and set that for a higher pressure that way it's going to open up first and it's also going to close last thinking in those terms all right so in other words if we set the valve higher let's say we set it at 80 psi and we set the other one at a lower pressure when the pressure on the downstream side lowers because somebody opens a fixture what's going to open up first the one that's set higher it's going to want to start sending flow so this the small valve is going to open up and then as the flow increases the large valve opens up I'm often asked what pressure differential do I do the smallest pressure differential I've ever done in a system has been 3 psi but I'm normally more in the range of 5 and sometimes as much as 7 psi I have seen colleagues do 10 psi in the drive and that's just the way they have designed their system and and that's fine and you're gonna say why would they be at such a high pressure job remember that CV factor they're looking at the CV factor to try and get between the high flow rates in the small valve to the low flow rates in a big valve so you you've got to do that comparison so that's all you know that the pressure setting is all going to be part of your design where you're looking at the valve you're looking at the features of the valve what is the minimum flow rate that you want what is the maximum flow-rate I get out of that and also what is the pressure drop off and without so those are all the features what that we look at in trying to design the set points for the difference between these hi-low concepts so we get into larger commercial buildings larger residential buildings high-rise buildings I'm going to always be running a high low concept for the larger piping systems let's look at the certification requirements for the valve now we already said that we're talking plumbing today which is potable water which is drinking water based on federal law in the u.s. we must be lick free or that's called low let you know just so you know there is this my new amount of light that can be in the in the brass but so basically all these valves are going to be let free the same is going to be true up in Canada we're looking at like free in Canada as well again lead-free no LED low LED whatever you want to call it the valves because they're dealing with drinking water and potable water must be certified tennis of 61 now I list MSF 370 to 372 is just that no lead low lead standard the interesting thing is about says it complies with in SF 61 it also complies with 372 because when you go into the middle of NSF 61 it says for drinking water applications the following must comply with also comply with NSF 372 so if a manufacturer is just listing NSF 61 they also comply with 372 I can assure you about that's just how the listing process works now a lot of manufacturers are promoting The Living Daylights are the fact that they also comply with 372 and that's what they do next we get into the performance requirements those are identified in a SSE 1003 you want to call it that's referenced in in the US Plumbing Codes we get up into Canada the performance requirements are identified and being in csa 3:56 by the way the Canadian standards are also recognized in the US so we we have this harmonization that goes on between the two countries and then finally all the plumbing codes require these to be listed by a third-party agency your testing laboratories you'll see the picture I put on here is courtesy of my friends at my at my warranty labs if you're ever in the Ontario California area give them a call they'd love to give you a tour of their labs I've taken a tour of their labs fascinating not to disparage any of the other listing agencies I've also taken tours you l's labs which are fascinating they'd be happy to give you tours if you contact them ahead of time and the QA I I've been torso then and a number of other labs as well so always fascinating to see how they're testing our plumbing products and what they're doing to keep us safe and make sure the products are equality it's Kevin a quick question on that one yes let me go back I noticed that some of the valve specifications say NSF 372 but they don't say anything about NSF 61 in our literature does that if you have NSF 372 that doesn't automatically mean you have NSF 61 right it's a different debt that is throughout the the difference between those two and let me let me give you a quick overview why some manufacturers might do that there will be some pressure reducing valves that are going to be used on systems that do not supply drinking water now that might sound strange what what do you mean potable water nuts playing drinking water let's say I have a line that's supplying nothing but showers and bathtubs I can put in a 372 valve which is required to be let free by the federal government and then I don't have any drinking water coming out of those outlets so the plumbing codes actually don't require 61 compliance but if you have any drinking water going through the mouth it must comply with 61 so you know I try and convince well manufacturers that 61 is the way to go and that's the way they do it but some are looking for special PR B's that are only going to equipment or a system and they're not for drinking water applications but again for you contractors in the field don't confuse them don't get them screwed up because if it's serving or providing any drinking water whatsoever you must comply with NSF 61 Thanks all right let's look at some of the installation recommendations you're gonna find plumbing codes do different things they all have slightly different requirements some of them say for a PR B you have to put a filter or a strainer upstream of the PRV I happen to be a big fan of this requirement I like doing that all the time I was in in the past year or two I was out on a project and there was a 12-inch PRV and we were we had was actually a new building and we had some water damage and the water damage amounted to over a million dollars when we took this PRV out inside the PRV this 12-inch PRV was a rock that was about six inches long about three inches in diameter wedged into the orifice of the PRV which meant it was introducing any pressure whatsoever now the first thing you're going to say what the heck is a rock that size doing it in a water line well yeah somebody fouled up when they were putting the water line in and the rock got there so if there had been a strainer upstream you know the rock would have been caught in that strainer but that just gives you an idea and by the way the pressure coming through that was 300 plus psi so now you know why there was so much water damage in the building the other thing you're going to find is some codes are going to call for a pressure relief out downstream of a PRV now I'm not a fan of doing this unless there is a sensitive piece of equipment I remember one project when I was a young engineer and this piece of equipment in an industrial building could only take a maximum of X psi well if I put a PR v in and it fails and the pressure increases it can damage a multi-thousand dollar piece of equipment so I'm gonna put in some form of protection and relief valve is one way to do it now I happen to like other valves as well that actually you know of some some are called al to do and some of they're called all different names but what the valve will do is when you get high pressure it actually closes off so I trust the system down so you can do it that way as well so I just caution my engineering colleagues out there if you have something sensitive you have a PRV you want a additional safety of provision downstream of in the event that the PRV does fail then we get into some of the codes call for an expansion tank downstream of the Peoria the expansion tank is actually intended to handle thermal expansion when we start to heat water we get into our thermal expansion so this is one way of combating the thermal expansion is to use an expansion tank of course there's other design features that my engineering colleagues know they can be done for this but that is just one option and then you get into some codes we'll call for a water hammer rester either upstream or downstream or both you know again sometimes a PRV opens and closes very quickly some of them have slow opening slow closing features so it depends on what you're dealing but if you do have a quick closing one you do want to provide some form of protection from water hammer or hydraulic shock now this drawing that I have here is shown on the screen this I stole from Coletti 'n one of their specification sheets I happen to like it because it shows what I like which are the two shutoff valves now I happen to be a big fan of ball valves and I like to use ball balance a lot you could use gate valve or a butterfly valve in other words you want to follow up in valve but this will allow the PRV to be isolated most fun it goes to call for this but every engineer and every contractor has ever worked on these in the field or a Deltan design of some high-end systems knows that this is a proper way to install them because it allows you to now isolate the PRV and to service it maintain it replace it repair it whatever it might be you know without that you might be shutting down the whole system so it's a whole lot easier you know if you have isolation valves on either side of a PRV I think that's a good design feature for any engineer to include and for contractors I think it's a good installation feature you'll also see that there is a filter or strainer I happen to be a big fan of putting that in the water hammer arrestor this one you look at it and it's on the upstream side a lot of people say well it's on the wrong side of the PRV you know it's trying to handle hydraulic shock it should be upstream of it not downstream up actually there the reason for this being on the upstream side I mean on the downstream side excuse me is because the water hammer arrestor can also address the situation when this valve opens up when it starts to gradually open we have that heat of vaporization of water and all of a sudden you get this clogging noise or glunk you know and what's happening is it's the valve attempting to open and the little air pockets that are heating up and vaporizing and what the water hammer arrestor does it actually comes down that noise as well and softens that approach so it's interesting some people call that reverse water hammer I don't like that terminology but in any event the water hammer arrestor will help to you know sometimes when we talk about upstream and downstream one is handling one situation the other is handling the other situation which is the hydraulic shock would be upstream the heat of vaporization would be downstream the other thing I always like to say is provide plenty of room to service or maintain these valves this is a mistake that is often made I you know being an engineer the one thing we always ask architects more space or more room and the answer is constantly no you can't have it but I work with my architect colleagues and and gotten space and made him understand the need to put in room for PRP i when I'm in certain buildings I will put them in a closet off the corridor if I can get them into an equipment room I put them in an equipment room so I just want to make sure that they are available to be able to service a maintain I just got back from a project where I saw 9p RVs in this closet off the Carter and when I looked at the ones in the back I asked the contractor I said how you gonna service that one there you go I don't know well they were stacked to the point that there one in front of the other there's no way you could have gone to the one in the back I was like oops not a good way to do it so keep in mind that these are gonna require maintenance the other thing that I always point out that the pure B's can be noisy so consider that when locating it I had one high-rise building and there was 60 plus stories in Chicago area and the P RVs happened to be installed in the master bedroom in the ceiling and they actually ended up being right over the bed for the master bedroom and the people were being awakened in the middle of the night hearing them clicking and making noise well they do make noise so that's not a good location to put them I would never put them in a bedroom or over a bedroom all right let's look at the maintenance that we've been talking about and what's what's required keep in mind these are active valves that's why they make the noise they're their move they're constantly going that means the moving parts can wear out so when you get into a PRV I always say when you get into route and routine maintenance the larger the valve the more maintenance is required smaller mouths you don't need as much maintenance you get into a half 3/4 1 inch pal residential valve they're normally gonna hold up for a long period of time without much maintenance but you get into a big one and we're gonna have some problems the common failures that we get in in P RVs is probably the number as the diaphragm failing that's you know now the valve is not going to be able to set reset properly it's not going to perform so that's the number one failure that I typically see the number two is threading of the seat some call it wire drawing there's all kinds of terms basically looks like somebody ran its thread through it and what that typically means is that the system was not properly designed the mistake I've seen contractors do is they find a bow like that and they just replace it with a like valve I got you're gonna have the same problem don't do it look at the system bring in an engineer if you're not sure have them evaluate the design because it means that the valve is is fighting and it's trying to open its closing its and there's this war that's going on inside the valve what also happens is it leads to erosion corrosion sometimes downstream on the outlet side of the valve so you start to see well this erosion corrosion on the inside somebody did not get the design correctly so that means a revaluation to make sure that the valve is properly the system is properly designed quite often it also means there's not a high-low situation or the high-low is not properly set up the other thing we run into quite often on the large valves is I will find pilot lines that become blocked because of the water quality realized there's not a high movement of water in there it's more pressure so it's sitting stagnant and if the water's got a lot of dissolved solids and that they become blocked strainers and filters become blocked they also become blocked there are strainers on pilot lines they become blocked and then finally you get into springs losing their attention when we get into the maintenance schedule I just say the maintenance schedule is very dependent on the use of the system if I'm gonna high-rise building these are used all the time and they're constantly being I always say abused they're they're constantly open and closing doing what they're supposed to be doing you get into the next thing is the quality of the water I'm going to throw this out to my plumbing contractors friends you normally know what the quality of the water is in your area does it have high total dissolved solids are they high is the hardness very high you know do you have very hard water do you have corrosive water we get into some waters and we know they're highly corrosive and then finally on the maintenance schedule we look at the size the larger the valve the more often I'm going to have to maintain it the smaller the valve the less I maintain it now I happen to live in the Chicago metropolitan area and dealt with a lot of high-rise buildings the Chicago area now Chicago we take the water right out of Lake Michigan it's actually very good quality water it's treated well it's not high in corrosive 'ti we don't have to worry that much about hardness and typically I will extend a maintenance schedule on a large valve and tell them when they first install it to look at after three years and then recondition it after five that's typically what we can get away with in the Chicago area some of my colleagues will go seven years in the Chicago area again we're talking on large baths I normally tell them to at least inspect the valve on an annual basis and take a look and see if everything's functioning and operating correctly and then typically rebuilding them about maybe every five years you get into a small about the residential about let's say a three-quarter inch panel they might last for 10 or 15 years without any maintenance at all if you get poor water quality you might be having to service them on an annual basis you know it really depends on what is the water quality I mean I've seen some waters that are so poor that these things are going up in no time at all so now they're going to be you're going to need to service and maintain them all right so just keep that in mind a lot of it depends on what is going on but don't the the biggest mistake I find from both the engineering profession and the contractor profession is they think they put this valve in they walk away and they don't ever have to look at it again the biggest mistake you make Julius this might be a good place for a question that came in relative to maintenance and servicing in most PRV applications are their common symptoms that you would experience in a facility that would indicate that the pressure reducing valve needs either servicing or replacement yeah I wish there were nice features that told you you and I it'd be nice if there was alarm that one often said service service service you know but it doesn't typically what starts to happen is the valve gets noisier and you're gonna say why is it annoys ear is it may not have you remember these pilot lines if they become blocked or partially blocked they're not going to do the slow open it's a little closing feature they're not going to set it correctly so that's going to be an indication so noisy valve is is an indication noisier than normal because keep in mind these valves are already noisy to begin with and and I don't mean real noisy they just they will make noise the other thing that we will see is the change in the pressure settings if the pressure all of a sudden is rising that means something is going on and there the pressure is lowering and not coming up to the pressure I mean something's going on something's getting blocked something's getting fouled and of course if the pressure increases tremendously the diaphragm just been so is this some number of manufacturers will like let few offers the pressure reduced Bob sorry the pressure gauge as an option is this a situation where that would be handy to to kind of monitor any increase in pressure on the system side yeah I'm a big fan of always putting in pressure gauges both before and after the PRV they're they're not required you know but it makes life easy the only thing I caution people with is sometimes the pressure gauge fails before the valve does so you you got to make sure that the pressure gauge is reading correctly but the beauty is when we talk about that annually inspect what things I do and inspecting is I check the pressure we have I was at one building and they require the maintenance people to go around in once a week record the pressure on all the PRV stations and not a bad idea it gives them an idea as to how things are working and how they're functioning yep all right let's go on to where are these required the interesting thing is technically the plumbing code never requires a PRV it says that the water pressure is restricted to a maximum 80 psi now that 880 psi is at the fixture so at the outlet it's not in the piping system couldn't be in the piping system I have irise billings where I'm pumping up to you know the top of Willis Tower which used to be called Sears Tower you know so I I have my water pipe is much higher than 80 psi but at the fixture itself at the plumbing fixture cannot exceed 80 psi so when you have street pressure that exceeds 80 psi they the way to handle that is put in a pr8 put in a pressure reducing valve I have to live in the flatlands to the Midwest heck we're lucky to get 55 psi in the street so I never need a PRV for my home where I grew up in New Jersey I lived in a rather you know we called it mountainous people in the West Coast called up hills but it was a hilly area so I lived in the lower section of town the downtown area which was really down in elevation and in the street the pressure was a hundred and sixty psi well the home I grew up in needed a PRV when you went to the other end of town the pressure in the street was 30 psi so they didn't meet any P RVs there sometimes they had to put in a pump to increase the pressure and then somewhere along in the town was the street pressure was 80 psi and you know that's that's when from there and at higher elevations didn't need a PR b and everything else did the you get into certain multi-story buildings we'll talk about that in a second word you're creating your own pressure but let's let's hold off on that now again keep in mind that this applies to the outlet of the plumbing fixture so the PRV can be located in any place as long as I'm controlling the pressure at the fixture outlet if you look I'm showing some residential applications the first one a few my colleagues up here in the northern climes where I live look at the photograph that's on your the left-hand side of your screen and you go oh my god that will freeze now this is a place you know southern Florida you might go as far north maybe as Orlando maybe a little bit further you know going along the lower coast of the United States across Texas into New Mexico Arizona and Southern California and of course Hawaii you can get away with installations like this but I even say like if you go to Alabama you get into the mountainous area of Alabama you don't want to put this in because it's a lot colder up there in the mountains than it does in the lower sections and you'll see that these are residential where they're putting it right at the inlet of the supply to the home which is fine you know that's that's one thing you can do it'll work well there you know you can locate them anyplace else as well if you so choose so the what we've been looking at is predominantly your single-family dwellings and typically one PRV is installed just on the inland typically its installed downstream of the water meter nowadays we've got a lot of times backflow preventers being required and seeing a family to one sometimes water meter with built-in backflow preventers so we're not worrying as much in the good old days we used to worry about putting in a PRV with a bypass on it and the bypass would allow the thermal expansion to go through now we just treat the thermal expansion so we don't don't get too excited about that when we get into multi-story buildings or high-rise buildings that's where the supply pressure can easily exceed 80 psi just from the building design itself so for most multi-story typically high-rise buildings we're putting in a number of pee RVs to control the system pressure that building I told you about in Chicago that was more than 60 stories tall there were over 250 P RVs installed in that particular building so there's there's many options for locating the P RVs and the multi-story buildings and I want to go into too long but I just thought I'd take some stuff that I threw in from my high-rise plumbing design seminar that I do and you know most of you know when you raise a column of water one foot you increase the pressure at the base by 0.4 3 3 psi so if you are going to assume a 80 psi maximum and then we always allow for friction loss and some safety factors we say you can lose 45 psi in a zone so when you take that subtract 80 minus 145 that equates to about 104 feet or approximately an 8 to 10 story building per or 8 10 stories for zone so what we'll end up with is when we have this water supplied so let's say the water is at the start of the zone at the bottom is 80 psi we'll go up to the top will allow a drop of 45 psi from elevation change and we know at the fixture we're going to get at least 25 psi again we have losses in the piping as well now that 25 psi you're wondering what that is well based on that's the pressure required to operate a compensating shower valve so that's the pressure we look at most residential buildings if you get into commercial building where we're using a fluorometer for water closet or a urinal the majority of them will operate also with 25 psi some claim they can operate as low as 20 then you get into some of the higher end flush valves would say they need a minimum at 35 psi so it's something to consider in the design you just have to know what pressure you need for what whatever that particular building is so we get into when we're over a 10 story building will do the zones and I'm showing here a simple high-rise I don't know how many stories that might be 16 stories or something like that so on the lower floors doing an express riser here and what that means is we're pumping the water up from the lowest level and then we're then putting in a PRV and then dropping the pressure and feeding it down so this is enough feet down for you type of system engineers like doing down feed systems because they feel that they can control the pressure better there's questions to that I happen to like down few systems myself that's just me as an engineer so in this particular situation the upper floor is of course we don't need a pure B because we're going to set the pump so that it never exceeds that eighty psi for the upper floors and then for the lower floors we've been put the PRV and and we're going to set it in this particular case we'll probably set it for 35 or 40 psi 35 is the typical and then we'll drop it down and at the bottom level it's going to be you know you're 80 psi now in a situation like this your minimum number of P RVs per zone are going to be two one on the hot water one in a cold water you got to remember you got hot water as well the better installation of course is going to be a minimum of four per zone two on the hot and two on the cold you remember how it's going to have a high end and a low end so you've got the high low situation for the flows and cold is going to have the high and the low as well so that that's where your four balance come in and that's going to be pers own now you can see how in a multi-story building that high-rise buildings easily easy to get over 250 POVs when you're over 60 stories tall now you could in your design if you wanted to put a booster pump in for every zone and that if you look at this particular design I don't need any PR B's in the building because I just set my pump up this way this is not an intelligent way of doing I rather put in a pumping package with a VFD pumping package and have a single Express riser and put in PR beats less piping involved easier pumping package so again I'm just showing options I don't call this an intelligent option it's just one that's available and then you know finally you get into the other type of design we'll see we tend to say that in high-rise buildings the plumbing goes from being piped horizontally to being pipe vertically but some engineers and contractors choose to do the combination vertical and horizontal that's what this is showing where they put in the main run-up and they'll put a few leaves and then they'll still pipe horizontally on I'm not a big fan of this design but I've seen it done when you do it this way they'll put in a PRV on every floor I I was at a building into Queens New York and every dwelling unit in this high-rise building had their own PRV perfectly acceptable you can do it that way you notice on the upper floors here there are no PR bees that's because again our pumping package for the upper floors are going to be such that the pump takes care of the pressure differential and we never go above that 80 psi and then finally we're showing the typical zone this is a 2 zone system where again I have my booster pump package and then I get my lower floor so I go through a PRP and I have a down feed system and then on the upper floors I don't meet a PRV because I'm setting my pump to handle the at upper zone so that I don't need the PRP the the interesting thing is when we're doing high-rise design all we're doing is starting to stack these zones so you know when you say when again the tallest building I've been involved in is his been over 60 stories I haven't done a hundred story building but if you had under storage you just start stacking zones that's all you're doing so you just put in these multiple therapies per each zone and and that's how we handle this situation if there are any questions I'll take them right now you good question I do not use them in series now I will give one exception to that in my youth as an engineer when I was a young engineer I did industrial buildings and there I would do them in series because we would be stepping down sometimes we'd be going from 300 to 150 down to 60 psi now I would be running him in series because I could control my situation better but you know in a potable water system I normally do not do them in series and the reason being is if you put in series what typically happens with the valves is if you don't set them up correctly the valves start fighting with each other everybody says what do you mean they're fighting with each other well what's going to happen as soon as I open a fixture downstream the downstream valve is the first one that has to open and it wants to open and but it has no flow because the upstream valve is closed so now the upstream valve has to open so you see I start this fighting between the two valves I'm better off with one valve that's going to control that pressure drop and typically in when you get into plumbing systems I'm not in a pressure that demands a two-step down situation so if I put them in in series those valves are always fighting with each other and you will see premature failure of the bath and you will find that's going to be extremely difficult to control the pressure I want to thank Julius again that was really really good Julius we learned a lot and there's an if there's nothing else thanks everybody and send your questions in we will answer all of them have a great afternoon thanks for thanks for attending

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