1 00:00:00,000 --> 00:00:05,900 Welcome back to Teaching the Unteachables, where we dive into teaching and learning 2 00:00:05,900 --> 00:00:11,080 methodologies for professionals like you. This episode brought to you by 3 00:00:11,080 --> 00:00:16,080 Stanfield Training Solutions, your source for HVACR training solutions. 4 00:00:16,080 --> 00:00:22,480 Learn more at hvacrfundamentals.com. 5 00:00:23,520 --> 00:00:28,100 Well hello everyone, thank you for joining Did You Know? the ESCO HVAC 6 00:00:28,100 --> 00:00:33,200 podcast. So today we're joined by esteemed author Carter Stanfield. How are 7 00:00:33,200 --> 00:00:39,440 you sir? I'm doing great. Author of Fundamentals of HVACR, published by 8 00:00:39,440 --> 00:00:46,120 Pearson. Carter is very involved with education as well as authoring in the 9 00:00:46,120 --> 00:00:51,800 industry and we both have a passion for understanding where things come from. I 10 00:00:51,800 --> 00:00:54,880 always say that you can't know where you're going unless you know where you 11 00:00:54,880 --> 00:01:00,560 came from and that's very true when we start talking about this A2L transition. 12 00:01:00,560 --> 00:01:05,680 And really it's a, when we look at it, it's more about the low GWP transition 13 00:01:05,680 --> 00:01:09,700 because yes we're seeing the A2L transition but we're also seeing an A3 14 00:01:09,700 --> 00:01:14,440 transition as well. And so today we're going to spend some time talking about 15 00:01:14,440 --> 00:01:18,680 where the standards come from, particularly ASHRAE Standard 15 and 16 00:01:18,680 --> 00:01:24,400 Standard 34. And Mr. Stanfield has spent a lot of time breaking these down and 17 00:01:24,400 --> 00:01:30,280 Carter if you could help us understand a little bit about this transition and why 18 00:01:30,280 --> 00:01:37,680 we're doing the things that we're doing. Sure. So I like to emphasize it you 19 00:01:37,680 --> 00:01:46,880 mentioned knowing where things come from. I like to look at the the original 20 00:01:46,880 --> 00:01:54,380 documents to things. So while I love presentations given by people, I like to 21 00:01:54,380 --> 00:02:00,840 see the original documents where their information came from. Absolutely. So when 22 00:02:00,840 --> 00:02:09,480 it comes to refrigerant, ASHRAE 34 is the standard that really all codes and 23 00:02:09,480 --> 00:02:20,080 even the UL qualification refer to. So ASHRAE 34 is the document that gives the 24 00:02:20,080 --> 00:02:25,960 refrigerants their numbers and also it's where our safety standard comes 25 00:02:25,960 --> 00:02:32,360 from. So the A1 through B3 and all the numbers and A2L, all that comes from 26 00:02:32,360 --> 00:02:38,140 ASHRAE 34. So I like to be able to refer to the original document and see 27 00:02:38,140 --> 00:02:44,080 exactly how they define things. This is particularly important now as we try to 28 00:02:44,080 --> 00:02:50,760 understand what an A2L is versus say an A1. Yeah absolutely. A lot of people 29 00:02:50,760 --> 00:02:54,920 don't realize you know where these transitions come from. We get a lot of 30 00:02:54,920 --> 00:03:00,320 calls at the ESCO office and sometimes complaints about these transitions going 31 00:03:00,320 --> 00:03:04,120 why are the manufacturers of equipment doing this to us again? And it's 32 00:03:04,120 --> 00:03:08,840 actually never been the manufacturers of equipment. Like when we talk about this 33 00:03:08,840 --> 00:03:14,160 A2L transition, we're really talking about the HFC phase down that came 34 00:03:14,160 --> 00:03:17,120 through in two different ways. It came through with a Kigali amendment to the 35 00:03:17,120 --> 00:03:22,480 Montreal Protocol as well as a portion of the AIM Act. So not only do we have an 36 00:03:22,480 --> 00:03:26,200 act of Congress but we have an international treaty that is phasing 37 00:03:26,200 --> 00:03:31,640 down the use of hydrofluorocarbon refrigerants. And so in doing that we 38 00:03:31,640 --> 00:03:34,920 have to look at what are the next generations of refrigerants, how do we 39 00:03:34,920 --> 00:03:39,200 safely handle them, and what other refrigerants could we see going forward? 40 00:03:39,200 --> 00:03:43,240 Because this is just one step of a variety of transitions that I'm sure 41 00:03:43,240 --> 00:03:48,800 we're going to see. Now many of us seen the CFC phase out. We've seen the H CFC 42 00:03:48,800 --> 00:03:54,560 phase out. We're now in the HFC phase down and remember it's not a complete 43 00:03:54,560 --> 00:04:02,200 phase out but it is a phase down by 85% by 2036. So what that means is we have to 44 00:04:02,200 --> 00:04:06,920 start looking at what other refrigerants do we have to work with. And you know 45 00:04:06,920 --> 00:04:10,920 we'll take chemists like Dr. Chuck over at Comoros who says that the periodic table 46 00:04:10,920 --> 00:04:16,400 doesn't really grow. We just have to reuse the elements that we have. And in 47 00:04:16,400 --> 00:04:21,080 doing that unfortunately we we end up with refrigerants that will have some 48 00:04:21,080 --> 00:04:25,240 mildly flammable and even highly flammable characteristics going forward. 49 00:04:25,240 --> 00:04:29,720 But then like how do you work with them? How do the manufacturers design the 50 00:04:29,720 --> 00:04:33,440 equipment? How did the tool manufacturers relook at and sometimes 51 00:04:33,440 --> 00:04:37,560 redesign their tools? There's a lot of safety that goes into that and we have 52 00:04:37,560 --> 00:04:42,640 to have something to start with. And that's really where ASHRAE 34 comes into 53 00:04:42,640 --> 00:04:49,680 play. Yeah ASHRAE has been doing refrigerant safety for quite a while and 54 00:04:49,680 --> 00:04:56,320 again it is really the backbone of most of the refrigerant safety standards. 55 00:04:56,320 --> 00:05:06,240 ASHRAE 15 which is also widely documented is used in many codes and 56 00:05:06,240 --> 00:05:13,040 essentially all the rules for refrigerant mechanical rooms, mechanical 57 00:05:13,040 --> 00:05:18,920 rooms and refrigerant systems in them basically refer back to ASHRAE 15. The 58 00:05:18,920 --> 00:05:24,040 issue that we've had with ASHRAE 15 is that it's primarily a commercial standard. 59 00:05:24,040 --> 00:05:32,760 Right. People don't have mechanical rooms in their houses. So ASHRAE 15.2 60 00:05:32,760 --> 00:05:41,800 covers low-rise residential structures and specifically really lays out all 61 00:05:41,800 --> 00:05:48,600 the safety requirements for installing and servicing A2L systems. It does also 62 00:05:48,600 --> 00:05:57,000 cover A1 systems but its primary purpose for being has to do with installation 63 00:05:57,000 --> 00:06:04,720 and service of A2L systems. And it was developed sort of in parallel with the 64 00:06:04,720 --> 00:06:16,640 UL, the number? 60 335-3-40. Okay thank you. Absolutely. And that UL standard 65 00:06:16,640 --> 00:06:23,560 actually came from an IEC standard of the same name, the same number. That's 66 00:06:23,560 --> 00:06:26,600 why they came up with that number because they harmonized the standard 67 00:06:26,600 --> 00:06:33,040 with the IEC standard. There's something that you know when we talk about 68 00:06:33,040 --> 00:06:38,160 worrying about global warming and getting rid of our high global warming 69 00:06:38,160 --> 00:06:44,040 refrigerants, this is not just a US thing. This is an international thing. That's 70 00:06:44,040 --> 00:06:49,040 right. The reason it's important to manufacturers is that we don't want to 71 00:06:49,040 --> 00:06:54,320 be on an island. We don't want to be the only people in the world using a 72 00:06:54,320 --> 00:06:58,440 particular type of refrigerant or having particular kinds of systems. The 73 00:06:58,440 --> 00:07:03,720 manufacturers both of the refrigerant and equipment want to be international. 74 00:07:03,720 --> 00:07:07,200 They want their products to be able want to be able to sell their products 75 00:07:07,200 --> 00:07:16,360 someplace besides the United States. So that gives some impetus. It's not just 76 00:07:16,360 --> 00:07:24,720 the government. There's also you know financial and industrial things 77 00:07:24,720 --> 00:07:30,400 at play here. And again it's an international movement. So it's not 78 00:07:30,400 --> 00:07:34,880 something that our government could just say okay well we don't want to do this 79 00:07:34,880 --> 00:07:39,360 anymore because we don't believe in it. We'd be bucking the whole world and 80 00:07:39,360 --> 00:07:45,880 basically it's sort of like isolationism. When we start talking about the the 81 00:07:45,880 --> 00:07:49,600 three different levels of mitigation what we're really talking about is the 82 00:07:49,600 --> 00:07:53,520 refrigerant concentration levels based on the flammability of the refrigerant. 83 00:07:53,520 --> 00:07:57,360 And when we start breaking down those refrigerants, so we started in ASHRAE 34 84 00:07:57,360 --> 00:08:02,520 to see what those flammable characteristics are, and then in 15-2 we 85 00:08:02,520 --> 00:08:05,880 can actually look at well when does that mitigation come into play because these 86 00:08:05,880 --> 00:08:09,960 smaller systems under four pounds and that's a rough estimate based on the 87 00:08:09,960 --> 00:08:14,080 refrigerant itself, under four pounds in these residential systems they actually 88 00:08:14,080 --> 00:08:20,800 don't even have mitigation. But once we reach that potential for combustion we 89 00:08:20,800 --> 00:08:24,960 actually we start adding mitigation to it. And so what we're going to see in 90 00:08:24,960 --> 00:08:29,400 particular residential systems is mitigation controls which is going to 91 00:08:29,400 --> 00:08:33,920 add a refrigerant leak detection sensor and a control to be able to mitigate 92 00:08:33,920 --> 00:08:44,040 those gases in the event of an actual significant leak. Yeah so on the the 93 00:08:44,040 --> 00:08:55,360 mitigation levels the UL standard and also the ASHRAE 15.2 refer to levels that 94 00:08:55,360 --> 00:09:03,320 charge levels they call M1, M2, and M3. I believe the M stands for mass. That 95 00:09:03,320 --> 00:09:09,480 makes sense. You know I haven't verified that with anybody. I'm just trying to 96 00:09:09,480 --> 00:09:14,920 come up with some reason why they use that. And then when they talk about the 97 00:09:14,920 --> 00:09:21,680 maximum charge and that sort of thing they also use M. But anyway M1 is six 98 00:09:21,680 --> 00:09:27,680 times the lower flammability limit, M2 is 52 times the lower flammability limit, 99 00:09:27,680 --> 00:09:34,880 and M3 is 260 times the lower flammability limit. So the weight amount 100 00:09:34,880 --> 00:09:39,040 varies with refrigerant because it depends on the refrigerant's density and 101 00:09:39,040 --> 00:09:43,920 the lower flammability limit of the refrigerant. Right. And it does it's it's 102 00:09:43,920 --> 00:09:49,080 just under four pounds for R32 and honestly I don't know right off the top 103 00:09:49,080 --> 00:09:58,080 of my head what it is for 454B. But it's in that same range. And to get a 104 00:09:58,080 --> 00:10:03,400 perspective on this I looked up I thought about P-TAC units. Yeah. And I 105 00:10:03,400 --> 00:10:10,240 looked up a Friedrich P-TAC unit of 12,000 BTUs and their charge was 1.8 106 00:10:10,240 --> 00:10:17,520 pounds of R32. So well under this four pounds. Yeah. Meaning that those units 107 00:10:17,520 --> 00:10:23,200 and say window units like you'd buy your big box store don't require any kind of 108 00:10:23,200 --> 00:10:30,000 special mitigation. When you go between M1 six times lower flammability limit up 109 00:10:30,000 --> 00:10:35,280 to M2 52 times a lower flammability limit you do require mitigation. And 110 00:10:35,280 --> 00:10:43,200 there's lots of ifs, ands, and buts, lots of different things that alter what the 111 00:10:43,200 --> 00:10:48,880 what mitigation is required. So that gets kind of detailed. And then there's 112 00:10:48,880 --> 00:10:57,240 more mitigation required between M2 and M3. And at M3 the 262 times of lower 113 00:10:57,240 --> 00:11:05,440 flammability limit basically that's outside of the UL standard. So that would 114 00:11:05,440 --> 00:11:11,040 require a whole different document. Exactly. And that's going to be large 115 00:11:11,040 --> 00:11:14,760 quantities of refrigerant large systems. Probably the only time we're going to 116 00:11:14,760 --> 00:11:19,920 see that is going to be in large VRV VRF installations. And it really comes down 117 00:11:19,920 --> 00:11:23,920 to once we get to that point we're going to add additional controls like pump 118 00:11:23,920 --> 00:11:30,320 down solenoids and ways to be able to do additional isolation of the refrigerant 119 00:11:30,320 --> 00:11:40,280 itself. Yeah. The again the mitigation varies a lot depending on the quantity 120 00:11:40,280 --> 00:11:46,520 of refrigerant and also where the system is applied. That's the only thing about 121 00:11:46,520 --> 00:11:54,080 standard 15. The requirements for what you're allowed to do and what you're 122 00:11:54,080 --> 00:12:01,040 required to do vary based really on three things. The occupancy, that's the 123 00:12:01,040 --> 00:12:12,720 building, the refrigerant, and oh the system. Oh yeah. Okay. Yeah. So I'll start 124 00:12:12,720 --> 00:12:19,040 from here. The mitigation varies depending on the type of occupancy. 125 00:12:19,040 --> 00:12:23,960 That's the type of building it is. The type of system, the type of refrigeration 126 00:12:23,960 --> 00:12:31,480 system, and the refrigerant classification. So when we talk about occupancy we're 127 00:12:31,480 --> 00:12:38,600 talking about say institutional would be hospitals and things where you have 128 00:12:38,600 --> 00:12:45,360 people that cannot easily move. Be relocated. That getting everybody out is 129 00:12:45,360 --> 00:12:51,880 going to be a chore. Sure. And then when you talk about systems they've got 130 00:12:51,880 --> 00:12:56,720 several different kinds of systems but it really comes down to whether 131 00:12:56,720 --> 00:13:02,320 something is a high probability or low probability system. Now by high 132 00:13:02,320 --> 00:13:09,600 probability they're talking about the possibility or probability of refrigerant 133 00:13:09,600 --> 00:13:15,480 getting in the airstream in the building if there's a leak. So in our typical 134 00:13:15,480 --> 00:13:20,080 direct expansion systems are all high probability systems because refrigerants 135 00:13:20,080 --> 00:13:25,880 in the coil that the air blows over. Exactly. In the space. Yeah. So an example 136 00:13:25,880 --> 00:13:30,280 of a low probability system would be say like a chiller where the refrigerant 137 00:13:30,280 --> 00:13:34,000 cools water and then the water is pumped around. Even if you did have a leak the 138 00:13:34,000 --> 00:13:39,680 chance of the refrigerant getting in the air is extreme. Minimal. Yeah. So the 139 00:13:39,680 --> 00:13:46,620 standards are different for those. So until recently the standard ASHRAE 15 140 00:13:46,620 --> 00:13:52,840 would not allow flammable refrigerant in a high probability system. So the 141 00:13:52,840 --> 00:14:01,320 first allowance of any kind of flammable refrigerant in a high probability 142 00:14:01,320 --> 00:14:09,720 system came about in the 2019 revision of the ASHRAE standard 15. The ASHRAE 143 00:14:09,720 --> 00:14:18,600 standard 34 recognized A2L refrigerants in 2016 but it was not until 2019 that 144 00:14:18,600 --> 00:14:26,800 they said in standard 15 that you could use A2L systems in a high probability 145 00:14:26,800 --> 00:14:33,480 system and there's again lots of parameters. So that's where we get into 146 00:14:33,480 --> 00:14:38,400 the mitigation and the amount of mitigation and the type of mitigation 147 00:14:38,400 --> 00:14:45,720 varies based on the quantity of refrigerant and the application. Yeah a 148 00:14:45,720 --> 00:14:49,760 lot of people don't realize that like you'd mentioned before a lot of our 149 00:14:49,760 --> 00:14:54,000 window units and P-TECH units have already made the transition to A2L 150 00:14:54,000 --> 00:14:58,680 refrigerants. Pretty much any window air conditioner you buy right now has R32 in 151 00:14:58,680 --> 00:15:04,000 it. Same way with the P-TECHs. Yeah you'd have a hard time actually finding a 152 00:15:04,000 --> 00:15:09,600 window unit that doesn't have 32 in it. Exactly and because of that charge limit 153 00:15:09,600 --> 00:15:13,600 of around four pounds most of those window units have a pound or under of 154 00:15:13,600 --> 00:15:17,520 refrigerant so they have no additional requirements for mitigation. In our 155 00:15:17,520 --> 00:15:21,680 residential and light commercial applications we're going to see factory 156 00:15:21,680 --> 00:15:26,800 leak refrigerant detection sensors as well as the controls that go with them. 157 00:15:26,800 --> 00:15:31,760 If it is a non-communicating system it's going to have a independent control 158 00:15:31,760 --> 00:15:35,560 module which is basically going to be connected between the thermostat and the 159 00:15:35,560 --> 00:15:40,000 indoor unit so that in the case of a detection we're actually going to go into 160 00:15:40,000 --> 00:15:43,960 a mitigation state which is going to turn off the outdoor unit. It would turn 161 00:15:43,960 --> 00:15:48,280 off any heat source inside whether it was electric furnace or whether it was a gas 162 00:15:48,280 --> 00:15:52,240 furnace it would actually turn off those ignition sources and turn on the blower 163 00:15:52,240 --> 00:15:56,560 to dissipate those gases. If it's a communicating system most of our 164 00:15:56,560 --> 00:16:01,160 manufacturers have incorporated that control into the indoor board and so 165 00:16:01,160 --> 00:16:04,080 literally it's a matter of just connecting the sensor that comes with 166 00:16:04,080 --> 00:16:09,040 the coil down to the control board of the indoor unit and now it's actually 167 00:16:09,040 --> 00:16:17,200 ready for a mitigation capable system. Yeah I didn't know that that's that's a 168 00:16:17,200 --> 00:16:22,800 good information. Yeah I've spent a lot of time on how we're actually utilizing 169 00:16:22,800 --> 00:16:28,080 the mitigation controls so if it is a non-communicating system you're going to 170 00:16:28,080 --> 00:16:34,240 have an additional control board. If it is a communicating system the the same 171 00:16:34,240 --> 00:16:38,640 refrigerant detection sensor is just going to be plugged into the primary 172 00:16:38,640 --> 00:16:42,440 control board of that indoor unit. At least that's what I've seen with the 173 00:16:42,440 --> 00:16:46,840 manufacturers that I've went through so far and then when we get into our VRV 174 00:16:46,840 --> 00:16:51,960 VRF because it's already a communicating board on the indoor unit that is able 175 00:16:51,960 --> 00:16:56,040 to communicate to the outdoor we're just adding the additional refrigerant 176 00:16:56,040 --> 00:17:00,480 detection sensor and it plugs directly into the control board. So as our systems 177 00:17:00,480 --> 00:17:04,960 make the transition it's going to be a little bit of a learning curve 178 00:17:04,960 --> 00:17:09,600 understanding what that installation looks like and in the installation 179 00:17:09,600 --> 00:17:13,320 manuals that I've seen for our residential like commercial split 180 00:17:13,320 --> 00:17:17,760 systems they actually give you all of the dimensions for if this system is 181 00:17:17,760 --> 00:17:23,280 installed in this cubic amount of space mitigation is required and here's how 182 00:17:23,280 --> 00:17:28,600 you make the connections. So it's pretty basic but it is definitely a transition 183 00:17:28,600 --> 00:17:32,760 that we're going to be making and it takes a little education and so the 184 00:17:32,760 --> 00:17:37,280 whole conversation today was where does that education come from. Most of it 185 00:17:37,280 --> 00:17:43,760 comes from standard 15 and standard 34. It's interesting that you mentioned the 186 00:17:43,760 --> 00:17:50,960 room volume it is one of the kind of significant changes. There the 187 00:17:50,960 --> 00:17:58,720 manufacturers part of the UL standard is they have to with the equipment when 188 00:17:58,720 --> 00:18:05,360 it's checked for the UL requirement they have to actually supply the 189 00:18:05,360 --> 00:18:12,080 installation instructions that they're going to package with the equipment and 190 00:18:12,080 --> 00:18:21,400 they have to provide tables rather than just formulas for technicians to be able 191 00:18:21,400 --> 00:18:28,560 to determine whether or not a particular piece of equipment will safely work in a 192 00:18:28,560 --> 00:18:33,620 space and they do that two ways. One of these they give they tell you equipment 193 00:18:33,620 --> 00:18:39,760 with this charge can go in a space no smaller than and they give you you know 194 00:18:39,760 --> 00:18:45,320 the volume and the other is they say it will if your space is this size the 195 00:18:45,320 --> 00:18:51,760 maximum charge you can have is and they give you a number. You're also going to 196 00:18:51,760 --> 00:18:59,400 be required to calculate total charge meaning in a split system or a many 197 00:18:59,400 --> 00:19:07,240 split system adding charge for the for the line set. Now of course that's not 198 00:19:07,240 --> 00:19:16,600 that new but now it's a really legal requirement and something that a lot of 199 00:19:16,600 --> 00:19:23,760 speakers have mentioned in their A2L presentations is a lot of behaviors and 200 00:19:23,760 --> 00:19:31,240 procedures that have been best practice are now required practice if you want to 201 00:19:31,240 --> 00:19:37,480 do it safely. Exactly so that's all that's a little bit of education doing 202 00:19:37,480 --> 00:19:41,760 best practices are going to get you through a lot of the hurdles otherwise 203 00:19:41,760 --> 00:19:46,120 your installation manuals and training from your manufacturers and industry 204 00:19:46,120 --> 00:19:51,800 partners like all of us are here to help educate you and keep you current. So 205 00:19:51,800 --> 00:19:55,600 Carter if you're looking for more information where are some ways that 206 00:19:55,600 --> 00:20:04,440 people can locate Fundamentals of HVACR and Carter Stanfield? So I have a blog 207 00:20:04,440 --> 00:20:17,120 hvacrfundamentals.logspot.com and I have a website hvacrfundamentals.com 208 00:20:17,120 --> 00:20:24,440 and then if you you can also google Stanfield training solutions and I 209 00:20:24,440 --> 00:20:32,520 believe my website will come up. Also you can go to Pearson. Pearson has a website for 210 00:20:32,520 --> 00:20:40,320 the book so you can google the book title Fundamentals of HVACR and you 211 00:20:40,320 --> 00:20:46,600 should be able to find that Pearson website. Fantastic Mr. Stanfield we sure 212 00:20:46,600 --> 00:20:54,840 appreciate you joining us today. Thank you very much.