 From Sunny Honolulu, this is Howard Wigg, Cold Green, Think Tech, Hawaii. Welcome one and all. We know that Hawaii is the most beautiful climate in the world. However, we do have a situation when that beautiful sun hits walls or buildings or homes. The sun's radiant heat tends to penetrate through the wall and into the living space and we've got to get rid of that heat somehow. Why not just decrease, by a large margin, the amount of heat going through that wall? That is exactly what our guest, Gene Rooney, president of Hawaii Architectural Sales, he's a president and owner and we're going to be talking about vertical exterior walls and I will let Gene describe that and I would say that, oh, I have to say this is a private enterprise coming on to a government site. We are not endorsing green genes products and this is here for strictly educational purposes only. I need to say that. On that, Cherino, please take it away, Gene. Good morning, Howard. Thank you for having me. We are here to talk about ventilated cavity rain screen systems. A ventilated cavity rain screen system is where you have a airspace between the cladding portion of your walls and your structural part of your walls. Maybe we can bring up the first slide here and talk about, let's start by talking about the two portions of a wall. So every wall generally has a structural component to it. That could be steel gauge framing, it could be concrete, it could be hollow tile and then on top of that in front of that you have another portion which is typically used in most places. Sometimes we don't know who uses it here but it's a cladding. So basically, it could be E-fist or it could be a hardy plank or it's something in front of the wall that's non-structural. It usually serves a couple of purposes. One is decorative, makes the building look nicer. And the second wall is a pretext or structural wall from the elements. So we can go to the next slide. So either that cladding can be applied directly to the wall in the case maybe with like a hardy plank or an E-fist or that cladding can be offset from the wall by a little bit and we can create an airspace behind that cladding and that airspace serves two purposes. So the first purpose was, or the first way this cladding was first designed was called pressure equalization and the purpose of introducing that airspace was to reduce, was to create a cavity, a small cavity that reduced that equalized the pressure between the interior and the exterior of the building. And the goal here was to stop water and air infiltration into the building because if you've got your internal pressure and your external pressure are the same, your water is not going to penetrate into your building and run down and run down the side of the building. So that was where the idea of rain screen cladding came from. So rather than having your cladding be directly applied to the building, we're going to move the cladding a little bit off the building, create an air pocket that equalizes the pressure. So if you go to the next slide, you can see some of the different types of material that are used for cladding. It can be really any material, metal panels are common, fiber cement panels, concrete panels, a technology that I like that will cover a little bit more here is a porcelain panels, but can also be any other type of ceramic panels. Terracotta is a very popular material used in Europe quite a bit. So the cladding is different from the structural wall. Okay, so if we go down to the next slide, you just basically just talked about the cladding is non-structural, it's just aesthetic, it's in front of the wall, it's not carrying the loads of the building, all that is done by your structural wall behind it. Okay, so these rain screen systems decrease the amount of, sorry, decrease the pressure and the amount of air and water that go through, and they do decrease the sun by a little bit. So go down a couple more slides. So go down to slide number six when we talk about a ventilated wall system. So the difference between a standard pressure equalize system and a ventilated system is we greatly increase the space okay between the cladding and the wall. So now we have a ventilated cavity that's also open at the top. So basically this your cladding now is acting as basically a sunscreen as well as an aesthetic feature because the heat that reaches that cladding is far enough away from the wall that while it may heat up the air in the cavity that air is quickly then it hot air rises. So cool air is brought in from the bottom, the hot air quickly rises to the top and now we are equalizing the temperature okay so that all that solar radiation that you mentioned is now it's heating up the cladding portion of the building but it's not heating up the structural wall. So in the diagram here you can see a structural wall here and you know one of the elements here you see is this exterior insulation on the wall. That's actually something new for us here in Hawaii. It's typically we had insulation maybe if we had studs we had insulation between the studs or we had a concrete wall or hollow metal wall that was considered enough insulation. Only recently in the building codes have we required this this exterior insulation on the outside. So if you look on the on the right side you can see how the sun hits the exterior of the building and during the course of the day it greatly heats up okay. So while our ambient air temperature as we were talking about before we started our ambient air temperature here in Hawaii is almost perfect year-round. I mean 75 in the winter 85 in the summer might get to 90 degrees a couple days of the year but there's very little temperature difference between what we would like the temperature to be inside and what the outdoor temperature is. I mean it's why most of the year everyone's happy sitting on their lanai as long as you're in the shade right. It's very comfortable here in Hawaii as long as you're in the shade and the second you get out of the shade things change right. It's even though the air temperature may be 79 degrees once that solar radiation starts hitting your skin you start to burn and things go up. It's exactly the same thing with a wall system so once that solar radiation starts hitting the wall it's going to go up into the hundreds of degrees and that heat's going to start transmitting through the wall eventually it's going to start heating up the interior air space of your building and you're going to have to turn that air conditioning on or you're going to have to go sit outside the lanai if you don't have air conditioning. So by moving this cladding outside the wall it's basically a sunscreen system for your house for your building basically that cladding is now either reflecting it's reflecting a good portion of the heat if depending upon you know the color whatnot but even if it's not reflecting that heat it's really only heating up the the air in the cavity okay between the wall and the cladding and that hot air is going to rise up and out the top before it has a chance to increase significantly in temperature and then translate and then transfer that heat into the building. So that's the the basic concept of a ventilated cavity system and you can see here if you go to slide up go to slide up 10 so you can see this you can see this in action here basically the sun is hitting that rain screen system and some of it's reflecting off but some of it is transmitting through it but it just goes up and out. Gene is that what they call the venturi effect where the hot air automatically rises and it gives you space? Yeah essentially yeah yeah so that's that's that's basically you know how how raising cladding assistance work we call it the on slide 12 we call the chimney effect uh venturi effect a little more technical name for it but yeah it's basically hot air rising so um and we can use different materials for this and use metal panels um on 13 we show a honeycomb panel which also this is called a double ventilated system because the panel itself has basically got perforations it's basically got um holes in it that allow the heat to to again to dissipate so the more ventilation the better on slide 14 you can kind of see what it looks like installed you can put this material you can put a cladding material um on top of any other uh wall system regardless of how the you know whether it be a a stud wall or a concrete wall uh basically attached with clips um get attached to the material and then get attached to the building um you know here it shows insulation which is which is common uh and you definitely want to use that insulation in a cold climate uh you know the interesting thing about these systems is is they're mostly studied on their effect in cold climates because that's obviously where most of the the energy is spent in the united states it's it's on it's on buildings in northern climates um and they're mostly focused on reducing heating costs as opposed to you know we're in a completely different situation here we're reducing cooling costs um so there's not a lot of study in terms of how it affects that so having the panels here in a way obviates the need for that insulation because if you're now if you're at that insulation that wall is not getting hit by any solar radiation that insulation is really not doing too much that insulation there is designed to slow the transmission of that uh temperature from the exterior to the interior but now you know we've kept that we've kept the exterior we've stopped that exterior wall that insulation from heating up and now we've got an exterior temperature that's maybe 10 degrees you know 10 degrees different from what we want our interior uh temperature to be um and with such a low you know difference you're just not going to get a lot of transmission to it so it's basically it's like putting a you know just like the energy code currently allows for uh reduction in solar heat gain on windows when it has a sun shade or some sort of projection above it maybe a balcony or something like that you know we recognize the fact that reducing the direct radiation on the glazing um you know obviates the need for some um some of its energy performance this is a similar way this is like a sun shade for the whole building basically you're you're you're you're putting a sun shade in front of the building to stop the building from heating up to begin with so instead of instead of focusing on increasing the insulation in the wall and increasing the u-value or the r-value I guess we were talking about I'm a fenestration guy so I've talked to u-values but maybe r-values so instead of focusing on improving the r-value of the wall it's it's a different approach to say instead of stopping the transmission of heat from the exterior to the interior let's stop the exterior wall from heating up to begin with and then we don't have to worry about the heat transmitting through it yeah gene I once measured the temperature of a dark wall where the sun's radiant heat was directly striking it yeah and I came in at 167 degrees sure and then I went just a few feet away where that same wall was totally shaded and the temperature dropped to I believe it was 93 degrees yeah like a 70 degree delta between the two exactly exactly it's you know it's a unique situation here in Hawaii it's all of our energy is problems that we have to deal with or where we have direct solar radiation which is you know extremely intense but our ambient air temperature most of the time is just fine you know it's like everyone comes home from work right and they first thing they do is get home from work and open up all the doors and windows and go sit in the garage for for an hour while the house cools down right because it's it's it's it's now 20 30 degrees hotter inside the house than it is outside you know the energy target for most people is I just want my house to be as cool inside as it is outside you know I mean it's the house would be comfortable if it was the same temperature inside as it is outside so um much different situation than even other southern climates you know we're not Las Vegas we're not phoenix we're not where we have 120 degree air temperature outside and um but here's a here's an example of a building that actually has a has a ventilated cavity range screen system and this is actually in the west bank and and Nazareth and the city hall there and you can actually see how the panels are actually offset by different depths from the building so they don't have to all be at the same projection factor off the building so it gives it an unique a unique scratcher and then there's a backlighting in there as well so this is basically a great basically a sunscreen system you know for the building um the whole side of the building so and we do this quite a bit too sometimes with the metal system sometimes you see out there with metal um vertical sunshade systems and things like that but usually it's usually it's on top of the fenestration right we're concerned about heat coming in through the fenestration so we put a sunshade um this is a similar concept but it's it can be applied to the whole building applied to the whole it can apply to the whole whole structure doesn't have to apply just a fenestration and it and it's especially valuable here because like I said this we don't once you get that stop that wall from heating up you don't have 110 degree air temperature outside that's going to continue to heat you know heat through the wall right now you've you've lowered that wall temperature to 80 degree some you know somewhere in the 80 degrees you know you know or whatever the ambient air temperature is you know outside we're actually and to your example it actually the walls would actually be cooler than your example of the 93 degree you know wall and shade because what's happening here is that we've talked about the venturi effect the chimney effect the cool air is constantly being brought in from the ground level and then being pulled out the top so your cooler air is right near your ground your ground because the cool air falls from hot air sinks so you actually have a constant breeze almost like blowing through that wall which is even better than having a static you know being you know static air yeah jim we don't normally think of air as being an insulator but i'm an energy codes guy and we reward buildings that have air instead of the direct radiant heat just passing by we count that as a form of insulation oh yeah i'm a fenestration guy so that's how you know insulated glass works we basically yeah you know we introduce an basically a half inch airspace between the the glass and has a huge impact on on on your value so yeah this is definitely you know similar to that and and that actually comes into play we were in a northern climate we were if i was giving this presentation in chicago we'd be talking more about how that airspace acts as an insulator um it plays a big part it plays a part here too but it plays a bigger role when that airspace that air insulating effect of that airspace plays a bigger role when you're in a northern climate like i said when here we it's it's uh you know if we're keeping the air temperature on both sides of that the same then as it's then the insulating for we're close to each other then the insulating effect isn't as important it's really important for us is basically that solar heat gain um you know stopping that radiant energy from hitting the wall to begin if we can stop that if we can keep that wall at the 90 degrees instead of going to 160 degrees i think you said or something like that then you don't have to be as concerned about the insulation factor of the wall and how that wall is going to stop that transmission through it so instead of throwing in instead of throwing insulation at the problem and in terms of stopping the transmission of this or slowing the transmission of the heat because the insulation doesn't stop it it just slows it right so instead of throwing insulation at the problem it's it's it's saying well let's stop it from heating up in the first place you know so yeah in the energy code we reward walls that are shaded now you might have a small shade or the best example in hawaii would be lanais where you've got at least 10 feet of roof area shading the that wall that's under the lanai and we reward the energy code we go down way way down and required insulation which which saves money and it makes sense because there's not that direct radiant heat from striking it now you are shading virtually 100 percent of the wall so yeah yeah exactly and it's going to work 100 percent of the time as opposed to you know with a with a lanai with a projection factor it's going to work you know and upon you know which way it's facing at the time of day you know some of that energy still going to still going to hit those walls so yeah I would be I would be interested in seeing how the energy code could could account for this and also you pointed out that this technology is also a a decorator very decorative factor too sure that that Jerusalem wall is just a perfect example right right it that's an architectural feature as in improving the aesthetics of the building and there's tons of different materials available for it I mean I think you know that's a porcelain system but you know typically metal panels have been the predominant material that's been used but you know GFRC is often used and I think I mentioned terracotta it's really you know up to the imagination the architect in terms of the material they want to use there's people who can use wood systems fiber you know fiber type systems yeah in the architecture field we call this passive cooling I mean just the design of the building prevents the influx of the radiant heat yeah yeah yeah and it's you know it's interesting the slide here I got is I have from that is from the middle east you know you know one of the companies I work with that makes the porcelain panels there's a tremendous amount of work in the middle east and and Africa and Spain are actually based out of Spain which also has a very hot climate so there are a lot of their work is done with passive cooling like you talk about because that's a the middle east is a large market for that sort of design there it's a they're very familiar with that concept so more so I think that in the United States or even in Europe a lot of the architecture there is built around passive cooling concepts and here in Hawaii for a very good reason PV panels or photovoltaic panels are very very very popular and one of course it makes electricity and with the battery storage electricity but a side effect is the fact that those panels are shading the roof yeah absolutely and if you notice if you look closely at the panels there are raised by at least say five if not six inches and that provides that airflow air space under the panel which is that's the horizontal equivalent of the vertical well that's critical that's critical for the efficacy of the panels they got to keep they lose their efficiency if they try to eat up too much so you got to keep your panels cool and you know and you can even incorporate you know solar into your vertical wall panels if you if you'd like to use that as a cladding user use that as a cladding material it's not out of the house yeah but it's obviously not as efficient as having a horizontal application you have to maybe on your south wall you can incorporate that you know I can use as well I mean the material you use is tremendous amount of options for the material that you can use the key thing is is the distance from the wall and all the open joints and the cavities and having an open at the top and so the air flows and definitely you can use different reflectivities on the panel I know you know the code allows for based on the reflectivity index of the cladding material you know some allowances and I think people sometimes struggle with they don't want to have a really bright building right in order to take advantage of the the code allowances for reflectivity you kind of have to have a relatively bright color right but if they want to have a darker color it doesn't really work whereas this doesn't when you're that heat isn't making it to the wall anyhow so it's not necessarily that the cladding reflects that heat because the panel can still absorb that heat it's still not going to get transferred to the structural wall whereas if that whereas if that like you said that dark if you're using like a dark fiber cement and it's right on top as your cladding and it's right on top of your structural wall you know it's going to heat up more than if you had like a white cladding right the white cladding is going to reflect a lot more on the energy um so we make allowances for that in the code but in this case because it's so far off the wall it really shouldn't matter uh whether the panel is absorbing or reflecting you know that energy yeah again in in the the roofing code we really really reward shading yeah in the roof and there is now the cool wall rating council I was instrumental in in founding that we're just getting our really good start and it's going to be part of code within the next year or so right and certainly we're going to have to uh include this as your technology as one of the uh the really cool wall factors yeah well I appreciate and reduce the amount of insulation required as a reward for that huge drop in in radiant heat right you know I have a I have a I have a NASA study that was done by NASA that I can send to you I don't really have it up here or I can bring it up here um but basically an independent study done and done on a a building for NASA in Houston and looking at their energy as they before and after they put the ventilated cavity on the building so that would be something pretty to take a look at as well I'd be interested in receiving that yeah yeah I mean it's just a lot of the research though like on the event like counties is more focused on the benefits for northern climates right as we we run into that a lot right there's not a lot of Hawaii specific studies or a lot of you know incentive for people to do research on our particular climate just because we're so small right so uh when they tend to do these energy studies they tend to focus on how can I reduce my heating costs in Chicago how does this affect my heating costs in Chicago not how does it affect my cooling costs in Hawaii right no that would make an excellent paper for a grad student at the UH School of Architecture oh sure yeah yeah I work closely with them I'm gonna can I pass your name on if oh sure sure yeah so what what is the uh the basis what's the bottom line of the NASA study that you mentioned uh I don't remember up top my head but it did show significant reductions in energy costs and cooling loads um specifically and it was basically a before and after energy consumption study before they they did the rain screen panels sorry before they did the the panels on it um and after yeah very significant you know reduction in cooling costs and climates like I don't know if anybody has had the the good fortune to be in the south in the middle of the summer yeah you have your combination of humidity plus right right heat yeah you know I mentioned um uh you know I mentioned you know Las Vegas and Phoenix as examples where you know they still also have the issue of its of its 110 degrees for three or four months a year so even if you can make the interior temperature the same as the exterior you're still gonna put your you still gotta run your air conditioner right because it's still 100 now you've only made it 110 degrees right yeah um and you and then you've got the issue in the south you know in Florida where okay even if I make the interior temperature the same as the exterior I still want to run my air conditioner because it's acting as a dehumidifier yeah because of the humidity so we're we're in almost a unique situation where if I can just get my interior temperature to not be hotter than it is outside then I don't need to put the AC on passive cooling yeah I'm not very very cheery note Jean we must bid you fond of your thank you Jean Ruby we're good on time for introducing us to this wonderful concept okay no I appreciate I appreciate it very much thank you for your time yeah that's our pleasure okay forward way code green think take away see you next time