1 00:00:01,680 --> 00:00:04,080 The following content is provided under a Creative 2 00:00:04,080 --> 00:00:05,620 Commons license. 3 00:00:05,620 --> 00:00:07,920 Your support will help MIT OpenCourseWare 4 00:00:07,920 --> 00:00:12,280 continue to offer high quality educational resources for free. 5 00:00:12,280 --> 00:00:14,910 To make a donation or view additional materials 6 00:00:14,910 --> 00:00:18,870 from hundreds of MIT courses, visit MIT OpenCourseWare 7 00:00:18,870 --> 00:00:20,020 at ocw.mit.edu. 8 00:00:25,878 --> 00:00:29,320 PROFESSOR: I'll do the Vanna White thing. 9 00:00:29,320 --> 00:00:34,340 So this sucks in air here, and inside, 10 00:00:34,340 --> 00:00:39,040 57% of methane or other combustible gases in it. 11 00:00:39,040 --> 00:00:43,330 And it sucks in about I think half liter a minute. 12 00:00:43,330 --> 00:00:45,900 And so you can get a percent gas in the air. 13 00:00:45,900 --> 00:00:50,200 And so luckily, at the moment, there's probably 0% methane. 14 00:00:50,200 --> 00:00:53,410 AUDIENCE: Is that what gas companies quickly 15 00:00:53,410 --> 00:00:54,160 use to find leaks? 16 00:00:54,160 --> 00:00:55,660 PROFESSOR: Yeah, yeah, they normally 17 00:00:55,660 --> 00:00:56,750 have a big probe on it. 18 00:00:56,750 --> 00:01:00,005 And what they do is they take bang bar, which 19 00:01:00,005 --> 00:01:02,130 is like a big stick and they stick it in the ground 20 00:01:02,130 --> 00:01:04,060 until they get a hole, and then they 21 00:01:04,060 --> 00:01:07,250 stick this with a probe on it, suck air in 22 00:01:07,250 --> 00:01:10,100 and figure out what the percent gas is in the soil. 23 00:01:10,100 --> 00:01:12,120 Then they know by where the highest percentage 24 00:01:12,120 --> 00:01:13,175 is in the soil. 25 00:01:13,175 --> 00:01:15,300 They figure, OK, that's probably where the leak is, 26 00:01:15,300 --> 00:01:18,180 and they start digging there. 27 00:01:18,180 --> 00:01:25,068 So it's a really simple and fantastic tool. 28 00:01:25,068 --> 00:01:27,550 CGI, yeah, combustible gas indicator. 29 00:01:27,550 --> 00:01:32,850 PROFESSOR: And right here is where the inlet is, 30 00:01:32,850 --> 00:01:34,350 OK, just off of here. 31 00:01:34,350 --> 00:01:39,000 We do this-- it's better to do it than in the back bumper, 32 00:01:39,000 --> 00:01:44,010 because there can be some exhaust contamination. 33 00:01:44,010 --> 00:01:49,740 Actually, well, two cars, we've tested it, do not interfere, 34 00:01:49,740 --> 00:01:51,720 but this is a little bit of an old van. 35 00:01:51,720 --> 00:01:55,520 So sometimes-- I mean, it passed the emissions test, 36 00:01:55,520 --> 00:02:00,370 but still there can be some contamination. 37 00:02:00,370 --> 00:02:04,030 That's why when we stopped, sometimes you'll 38 00:02:04,030 --> 00:02:07,600 get some measurements, but when you're moving forward 39 00:02:07,600 --> 00:02:11,710 and the wind is upstream, you know you're getting readings. 40 00:02:11,710 --> 00:02:14,440 This is the methane reading that analyzers 41 00:02:14,440 --> 00:02:16,720 are reading right now. 42 00:02:16,720 --> 00:02:20,310 So it's anything below 2, it's right now, 43 00:02:20,310 --> 00:02:23,690 1.96 is pretty clean. 44 00:02:23,690 --> 00:02:25,660 There's no leak where we are right now. 45 00:02:25,660 --> 00:02:31,510 So if it's under 2, you know we're in a place with no leak. 46 00:02:31,510 --> 00:02:36,720 And even if it creeps up over 2, if it's like 2.01, 2.02, 47 00:02:36,720 --> 00:02:40,330 that's not really indicative of a leak. 48 00:02:40,330 --> 00:02:44,020 But if you see it go up to like 2, 49 00:02:44,020 --> 00:02:47,005 your eyes can tell you in time that oh, it 50 00:02:47,005 --> 00:02:50,050 seems to be going up pretty rapidly here. 51 00:02:50,050 --> 00:02:52,765 And so you'll see it maybe go for 2.3 sometimes, 52 00:02:52,765 --> 00:02:54,460 and then drop back down. 53 00:02:54,460 --> 00:02:56,380 And that's kind of unusual. 54 00:02:56,380 --> 00:02:59,002 That's like, OK, there's probably something around here. 55 00:02:59,002 --> 00:03:00,460 And then every once in a while, you 56 00:03:00,460 --> 00:03:04,780 might see something that goes up further, 3, 3 and 1/2, 57 00:03:04,780 --> 00:03:08,710 and those are like definite leaks. 58 00:03:08,710 --> 00:03:11,490 AUDIENCE: What's the highest number you've ever seen? 59 00:03:11,490 --> 00:03:14,560 PROFESSOR: Well, in DC, we got I think very 60 00:03:14,560 --> 00:03:17,350 near to 100 parts per million. 61 00:03:17,350 --> 00:03:19,450 And that's in the air that we're breathing, 62 00:03:19,450 --> 00:03:22,040 so it's not explosive at that level. 63 00:03:22,040 --> 00:03:26,260 But it's like 50 times more than the background value. 64 00:03:26,260 --> 00:03:28,300 AUDIENCE: So 2 is baseline kind of background. 65 00:03:28,300 --> 00:03:30,008 PROFESSOR: Yeah, yeah, you can consider 2 66 00:03:30,008 --> 00:03:32,260 to be a baseline level. 67 00:03:32,260 --> 00:03:41,980 Now it's like CO2, well, it used to be 280 parts per million, 68 00:03:41,980 --> 00:03:44,320 and now it's like over 400. 69 00:03:44,320 --> 00:03:48,710 So 2 parts per million methane is the new normal. 70 00:03:48,710 --> 00:03:52,450 I mean it was 0.7 parts per million, preindustrial. 71 00:03:52,450 --> 00:03:55,090 So I would like to point that out 72 00:03:55,090 --> 00:03:59,180 that are our normal baseline is very abnormal. 73 00:03:59,180 --> 00:04:01,680 So we're going up about that with leaks. 74 00:04:01,680 --> 00:04:04,270 Now this is a timeline here, this graph, 75 00:04:04,270 --> 00:04:08,590 and you can see as I came in here, we did get 6, 7, 76 00:04:08,590 --> 00:04:10,540 we got a few leaks here. 77 00:04:10,540 --> 00:04:12,820 And that was right at the Allston/Brighton tolls 78 00:04:12,820 --> 00:04:15,610 coming down off of the Mass Pike. 79 00:04:15,610 --> 00:04:18,820 There's a leak there. 80 00:04:18,820 --> 00:04:21,000 AUDIENCE: So what happens in terms the reporting 81 00:04:21,000 --> 00:04:23,650 that or following up with it? 82 00:04:23,650 --> 00:04:26,200 PROFESSOR: So we don't have any evidence, 83 00:04:26,200 --> 00:04:28,270 but based on driving by. 84 00:04:28,270 --> 00:04:33,550 We can't say whether it's a green one hazardous leak, 85 00:04:33,550 --> 00:04:38,530 a grade two, or a grade three so-called non-hazardous leak. 86 00:04:38,530 --> 00:04:42,040 So I don't feel obligated that each 87 00:04:42,040 --> 00:04:44,590 what we see that OK, we got to call the gas company. 88 00:04:44,590 --> 00:04:48,160 First of all, they do know about these leaks. 89 00:04:48,160 --> 00:04:53,900 They know-- to a large degree where they are. 90 00:04:53,900 --> 00:04:56,680 But if we get out, and we could, because we have the CGI. 91 00:04:56,680 --> 00:04:59,770 If we decide to get out and poke around and look through it, 92 00:04:59,770 --> 00:05:03,520 and we find evidence that it is like a grade one, 93 00:05:03,520 --> 00:05:07,896 then that's when I feel obligated to call the leak in. 94 00:05:07,896 --> 00:05:09,670 'Cause it's like we have knowledge 95 00:05:09,670 --> 00:05:14,070 that something seems to be unsafe, 96 00:05:14,070 --> 00:05:15,733 and so then we call it in. 97 00:05:15,733 --> 00:05:16,233 Yep? 98 00:05:16,233 --> 00:05:17,732 AUDIENCE: Is there a clear indicator 99 00:05:17,732 --> 00:05:19,180 when it's a grade one? 100 00:05:19,180 --> 00:05:20,740 PROFESSOR: This machine is not going 101 00:05:20,740 --> 00:05:23,860 to be able to tell us whether there's a grade one, a grade 102 00:05:23,860 --> 00:05:27,230 explosive hazard, grade two, or grade three. 103 00:05:27,230 --> 00:05:34,510 And that's because you can have big leaks with lots of gas 104 00:05:34,510 --> 00:05:38,320 coming out that are not explosive hazards. 105 00:05:38,320 --> 00:05:41,480 Like the Porter Ranch gas leak in LA, 106 00:05:41,480 --> 00:05:44,800 Audrey makes this point a lot, it was technically 107 00:05:44,800 --> 00:05:47,090 a grade three non-hazardous leak, 108 00:05:47,090 --> 00:05:49,970 'cause it wasn't going to explode. 109 00:05:49,970 --> 00:05:52,180 And it wasn't that close to the neighborhood, 110 00:05:52,180 --> 00:05:54,610 it was like a quarter mile away from the neighborhood. 111 00:05:54,610 --> 00:05:57,700 So it's an indication that that grading scheme 112 00:05:57,700 --> 00:06:00,430 is only a single variable grading scheme. 113 00:06:00,430 --> 00:06:04,315 And explosion and hazard is a big deal. 114 00:06:04,315 --> 00:06:06,440 There's no doubt about that, and no one wants that. 115 00:06:06,440 --> 00:06:12,070 So what the grading scheme has to incorporate 116 00:06:12,070 --> 00:06:13,510 the amount of the flux. 117 00:06:13,510 --> 00:06:15,910 There is a GPS on this roof right now, 118 00:06:15,910 --> 00:06:18,185 and it's plugged into the back of the machine, 119 00:06:18,185 --> 00:06:22,375 and the data file that comes out is already integrated with GPS 120 00:06:22,375 --> 00:06:23,765 with the time stamp. 121 00:06:23,765 --> 00:06:25,040 Straight? 122 00:06:25,040 --> 00:06:27,554 AUDIENCE: Left, if we can, yep. 123 00:06:30,500 --> 00:06:34,250 So what are the objectives for today? 124 00:06:34,250 --> 00:06:40,680 Is it just to see how methane is measured, 125 00:06:40,680 --> 00:06:44,600 or are we trying to answer any particular questions? 126 00:06:44,600 --> 00:06:48,140 PROFESSOR: So what we call this is a gas leak safari. 127 00:06:48,140 --> 00:06:50,480 So one of the objectives-- 128 00:06:50,480 --> 00:06:55,590 OK, here we are, 2, 3, 2, 3, so there's something there. 129 00:06:59,220 --> 00:07:02,090 So just to educate and to show first 130 00:07:02,090 --> 00:07:06,560 of all what this process is of mapping the gas leaks. 131 00:07:06,560 --> 00:07:10,160 I think that we're going to places that we have surveyed 132 00:07:10,160 --> 00:07:15,530 in the past, Audrey and Heat did the study now, two years ago, 133 00:07:15,530 --> 00:07:17,810 is it? 134 00:07:17,810 --> 00:07:19,334 But things change. 135 00:07:19,334 --> 00:07:20,500 AUDIENCE: Take a right here. 136 00:07:20,500 --> 00:07:22,430 PROFESSOR: Right on Portland. 137 00:07:22,430 --> 00:07:26,634 2.1, 2.1, OK, here we have something, 2.1. 138 00:07:26,634 --> 00:07:28,050 So there's something here I think. 139 00:07:28,050 --> 00:07:28,633 AUDIENCE: 2.3. 140 00:07:28,633 --> 00:07:29,270 AUDIENCE: 2.5. 141 00:07:29,270 --> 00:07:29,862 2.7. 142 00:07:29,862 --> 00:07:31,320 PROFESSOR: OK, yeah, read them out. 143 00:07:31,320 --> 00:07:32,980 AUDIENCE: 2.8. 144 00:07:32,980 --> 00:07:39,082 PROFESSOR: OK, so there's a leak here in this facility. 145 00:07:39,082 --> 00:07:41,537 AUDIENCE: Portland and Main. 146 00:07:41,537 --> 00:07:43,010 AUDIENCE: So that's at 2.3. 147 00:07:43,010 --> 00:07:47,066 Oh, 3.3, well, 4.4, 4.4. 148 00:07:47,066 --> 00:07:48,064 AUDIENCE: 4.2. 149 00:07:48,064 --> 00:07:49,635 3.8. 150 00:07:49,635 --> 00:07:51,010 PROFESSOR: So you can see there's 151 00:07:51,010 --> 00:07:53,210 the spike on the leading edge. 152 00:07:57,210 --> 00:07:57,710 Right? 153 00:08:00,290 --> 00:08:06,530 It's really as you can imagine, as any lay person can imagine, 154 00:08:06,530 --> 00:08:09,610 the vagaries of wind are going to the plume. 155 00:08:09,610 --> 00:08:12,500 The plume is coming out of wherever it can come out. 156 00:08:12,500 --> 00:08:14,780 I could come out of a man hole slot-- 157 00:08:14,780 --> 00:08:15,454 straight on? 158 00:08:15,454 --> 00:08:16,370 AUDIENCE: Straight on. 159 00:08:16,370 --> 00:08:19,220 PROFESSOR: It could come out of the soil. 160 00:08:19,220 --> 00:08:21,990 A leak is going to to just find whatever parallel 161 00:08:21,990 --> 00:08:24,590 pathways it can get out. 162 00:08:24,590 --> 00:08:26,750 And so you can imagine, at the surface 163 00:08:26,750 --> 00:08:31,760 there's some kind of profile of this stuff coming out. 164 00:08:31,760 --> 00:08:35,059 And then the wind's going to carry it and blow it around. 165 00:08:35,059 --> 00:08:40,309 And so that makes it a little tough. 166 00:08:40,309 --> 00:08:43,490 We can't really pinpoint exactly where 167 00:08:43,490 --> 00:08:45,220 it's coming out of the ground. 168 00:08:45,220 --> 00:08:48,000 We can know when we have driven by it. 169 00:08:48,000 --> 00:08:50,150 There's a leak in this vicinity, and I would always 170 00:08:50,150 --> 00:08:54,140 say within 50 to 100 feet of where 171 00:08:54,140 --> 00:08:57,660 we measured it is probably part of the source coming 172 00:08:57,660 --> 00:08:59,030 on the ground. 173 00:08:59,030 --> 00:09:03,480 But to actually really pinpoint where the pipeline leak is 174 00:09:03,480 --> 00:09:06,480 would require stopping, getting out, and using the instrument 175 00:09:06,480 --> 00:09:10,290 that Audrey has as well as maybe some other instruments, 176 00:09:10,290 --> 00:09:15,950 handheld snippers to really find out where it's coming out. 177 00:09:15,950 --> 00:09:21,140 What you're realizing right now that makes it like discreet 178 00:09:21,140 --> 00:09:26,030 when we see a leak, if you look at this timeline here, 179 00:09:26,030 --> 00:09:29,870 this trace, you can see there's a lot of flat 180 00:09:29,870 --> 00:09:33,680 and then some fairly well resolved spikes. 181 00:09:33,680 --> 00:09:38,450 And so it's not very ambiguous when you get 182 00:09:38,450 --> 00:09:40,820 an elevated anomalous reading. 183 00:09:40,820 --> 00:09:43,940 It's like, oh, there's one, there's one, there's one. 184 00:09:43,940 --> 00:09:46,450 Here's a couple that are small, but they really 185 00:09:46,450 --> 00:09:50,190 need to go very clearly from the back ground. 186 00:09:50,190 --> 00:09:53,300 So there's not that much ambiguity about like, well, 187 00:09:53,300 --> 00:09:57,525 is this kind of giant blob a leak or not? 188 00:09:57,525 --> 00:10:02,205 They're well resolved spikes in time and space. 189 00:10:02,205 --> 00:10:03,580 AUDIENCE: What's the biggest leak 190 00:10:03,580 --> 00:10:06,205 you've seen in the Boston area? 191 00:10:06,205 --> 00:10:09,550 PROFESSOR: Maybe like 40 or 50 parts per million in the air. 192 00:10:09,550 --> 00:10:11,811 AUDIENCE: Where was that? 193 00:10:11,811 --> 00:10:14,310 PROFESSOR: Well, a couple of places that were close to that. 194 00:10:14,310 --> 00:10:21,700 One was Sullivan Square, Rutherford Street 195 00:10:21,700 --> 00:10:24,760 in Charles Town, kind of on the Somerville Charles Town 196 00:10:24,760 --> 00:10:26,480 border, the giant rotary. 197 00:10:26,480 --> 00:10:27,210 AUDIENCE: Yeah. 198 00:10:27,210 --> 00:10:28,960 PROFESSOR: I mean, we could go over there, 199 00:10:28,960 --> 00:10:30,250 there is a big leak there. 200 00:10:30,250 --> 00:10:33,313 And then Nonantum Road between kind of Watertown and Newton. 201 00:10:33,313 --> 00:10:37,248 2.2, 2.3, OK, so there's something here, OK. 202 00:10:37,248 --> 00:10:39,470 2.3, OK, so we've got, 2.5. 203 00:10:39,470 --> 00:10:40,782 AUDIENCE: 2.5. 204 00:10:40,782 --> 00:10:41,674 AUDIENCE: 2.8. 205 00:10:41,674 --> 00:10:42,803 3. 206 00:10:42,803 --> 00:10:43,610 3.2. 207 00:10:43,610 --> 00:10:45,482 4.8. 208 00:10:45,482 --> 00:10:46,450 AUDIENCE: 6. 209 00:10:46,450 --> 00:10:47,980 AUDIENCE: Oh boy. 210 00:10:47,980 --> 00:10:48,817 Oh boy. 211 00:10:48,817 --> 00:10:49,400 AUDIENCE: 5.3. 212 00:10:49,400 --> 00:10:52,220 PROFESSOR: So I mean, we could get out and take a break 213 00:10:52,220 --> 00:10:54,230 and find it if you wanted on this one. 214 00:10:54,230 --> 00:10:55,520 It's kind of quiet. 215 00:10:55,520 --> 00:10:58,340 This is definitely a much blunter instrument 216 00:10:58,340 --> 00:10:59,690 than that one. 217 00:10:59,690 --> 00:11:05,640 And it's made to find out like percent level, 50%, 10%, 218 00:11:05,640 --> 00:11:07,146 not parts per million. 219 00:11:07,146 --> 00:11:09,790 OK, so this is now when you want to find out 220 00:11:09,790 --> 00:11:14,198 where is it coming out at, OK? 221 00:11:14,198 --> 00:11:18,272 The professionals right now would have this bar, 222 00:11:18,272 --> 00:11:19,230 it's called a bang bar. 223 00:11:19,230 --> 00:11:22,140 It's like one of those construction pile drivers, 224 00:11:22,140 --> 00:11:24,160 it's like a handheld version of that. 225 00:11:24,160 --> 00:11:28,000 And you would find out, maybe right here, you'd 226 00:11:28,000 --> 00:11:32,800 like slam it down maybe up to a meter. 227 00:11:32,800 --> 00:11:34,280 And this would have a longer thing, 228 00:11:34,280 --> 00:11:35,446 and you'd stick it in there. 229 00:11:35,446 --> 00:11:40,510 Now I don't do that, because I'm not certified to do that, 230 00:11:40,510 --> 00:11:42,820 and I don't want to puncture any gas lines 231 00:11:42,820 --> 00:11:44,590 and create an explosion. 232 00:11:44,590 --> 00:11:49,720 So what I do is I just kind of do like this, 233 00:11:49,720 --> 00:11:53,220 and sometimes I'll use like a screwdriver or just a stick 234 00:11:53,220 --> 00:11:56,440 even, and kind of-- 235 00:11:56,440 --> 00:11:58,870 this is right at the surface-- 236 00:11:58,870 --> 00:12:00,550 and poke around. 237 00:12:00,550 --> 00:12:04,740 So actually look, there is something, point 0.2. 238 00:12:04,740 --> 00:12:08,260 Now the fact, 0.25%. 239 00:12:08,260 --> 00:12:16,250 So 0.25% is, let's see, 1% is 10,000 parts per million, 240 00:12:16,250 --> 00:12:19,020 right, 1% is 10, 000 parts per million. 241 00:12:19,020 --> 00:12:22,680 This is 8,500 parts per million right now-- 242 00:12:22,680 --> 00:12:24,960 0.85, 0.9. 243 00:12:24,960 --> 00:12:29,040 OK, so the thing is that this is right at the surface. 244 00:12:29,040 --> 00:12:32,340 If I was down even probably that much, 245 00:12:32,340 --> 00:12:35,590 it would probably be I don't know 15%, 20%. 246 00:12:35,590 --> 00:12:38,940 And if we went down a little further, this could be 90% gas. 247 00:12:38,940 --> 00:12:44,750 See this is 0.25. 248 00:12:44,750 --> 00:12:46,370 Yeah, so about the same. 249 00:12:46,370 --> 00:12:50,300 I'm just like about that far in. 250 00:12:50,300 --> 00:12:54,430 So this is an indication that there's definitely a leak here. 251 00:12:54,430 --> 00:12:57,140 And it's no mistake we got the 15 parts per million 252 00:12:57,140 --> 00:13:00,260 in the kind of air that we're breathing. 253 00:13:00,260 --> 00:13:03,020 So now let's look around for just infrastructure. 254 00:13:03,020 --> 00:13:07,160 Let's see I mean, that was a very arbitrary choice 255 00:13:07,160 --> 00:13:07,970 of a place to look. 256 00:13:07,970 --> 00:13:10,940 It's just we got out, we're here. 257 00:13:10,940 --> 00:13:13,500 But now I want to see like, OK, where is the gas line? 258 00:13:13,500 --> 00:13:15,800 AUDIENCE: And all that. 259 00:13:15,800 --> 00:13:20,110 PROFESSOR: That could be a vestige of a gas leak marking. 260 00:13:20,110 --> 00:13:23,240 And this big patch has been for some purpose, 261 00:13:23,240 --> 00:13:24,950 I don't know if it was a gas line. 262 00:13:24,950 --> 00:13:26,930 I see some more yellow paint out here. 263 00:13:29,870 --> 00:13:32,902 OK, so this is -- 264 00:13:32,902 --> 00:13:37,040 OK, yeah, always be very careful with the cars of course. 265 00:13:37,040 --> 00:13:42,920 So this is a service line coming off of the main, OK? 266 00:13:42,920 --> 00:13:47,960 So service lines going this way, mains generally going that way. 267 00:13:47,960 --> 00:13:50,480 Mains can be at an angle, they can 268 00:13:50,480 --> 00:13:55,406 be running under the sidewalk, so anything can really happen. 269 00:13:55,406 --> 00:13:56,780 AUDIENCE: So were mains laid down 270 00:13:56,780 --> 00:13:59,930 before the streets were gridded or something or what? 271 00:13:59,930 --> 00:14:01,809 PROFESSOR: Or sometimes afterwards. 272 00:14:01,809 --> 00:14:03,350 AUDIENCE: OK, but if it's afterwards, 273 00:14:03,350 --> 00:14:05,070 I'm going to assume that there-- configures to the street. 274 00:14:05,070 --> 00:14:07,670 PROFESSOR: They probably would do it running that way 275 00:14:07,670 --> 00:14:08,810 if it was done afterwards. 276 00:14:08,810 --> 00:14:09,757 AUDIENCE: OK. 277 00:14:09,757 --> 00:14:11,465 PROFESSOR: This is an electrical manhole. 278 00:14:15,470 --> 00:14:18,100 The gas can come in any-- 279 00:14:18,100 --> 00:14:19,700 it can seep in anywhere. 280 00:14:19,700 --> 00:14:23,330 So 0.25, OK, so gas in there. 281 00:14:23,330 --> 00:14:27,470 All right, so we did this. 282 00:14:33,050 --> 00:14:37,150 OK so, all right, so there's definitely gas in here. 283 00:14:37,150 --> 00:14:39,380 That's very, very clear. 284 00:14:39,380 --> 00:14:40,970 I mean, if you really wanted to, you 285 00:14:40,970 --> 00:14:42,770 could smell, and smell the gas, but I'm not 286 00:14:42,770 --> 00:14:45,410 going to recommend that. 287 00:14:45,410 --> 00:14:47,830 But this is not an explosive thresh hold. 288 00:14:47,830 --> 00:14:51,620 So I don't feel like, back off, don't smoke or whatever. 289 00:14:51,620 --> 00:14:57,450 Well, don't smoke, but if it were 4%, 290 00:14:57,450 --> 00:15:01,030 then that would be a grade one explosive hazard, OK? 291 00:15:01,030 --> 00:15:03,460 And we would call it in, and they 292 00:15:03,460 --> 00:15:06,750 would come out immediately, well, within a half hour or so. 293 00:15:06,750 --> 00:15:10,000 AUDIENCE: And again, 4% is what on that readout? 294 00:15:10,000 --> 00:15:12,380 PROFESSOR: 40,000 parts per million. 295 00:15:12,380 --> 00:15:15,500 4% is equal to 40,000 parts per million. 296 00:15:15,500 --> 00:15:19,270 So if the 4.0, that's 40,000 parts per million. 297 00:15:19,270 --> 00:15:21,760 And that's the lower explosion threshold, 298 00:15:21,760 --> 00:15:25,160 the higher explosion threshold is about 15% gas. 299 00:15:25,160 --> 00:15:28,420 If it gets above that, there's not enough oxygen 300 00:15:28,420 --> 00:15:29,769 for it to explode. 301 00:15:29,769 --> 00:15:31,560 PROFESSOR: All right, where little kids are 302 00:15:31,560 --> 00:15:33,685 like playing in the playground, there's a grade one 303 00:15:33,685 --> 00:15:36,540 leak under a manhole, we call it in, 304 00:15:36,540 --> 00:15:39,270 and these two guys from Evershore 305 00:15:39,270 --> 00:15:43,600 arrive, and they don't even have like a bang bar, 306 00:15:43,600 --> 00:15:47,358 and they didn't have the right instrumentation to do anything. 307 00:15:49,920 --> 00:15:52,200 So we pop open the manhole for them. 308 00:15:52,200 --> 00:15:54,855 And they look and they're like, yeah. 309 00:15:54,855 --> 00:15:56,730 Then we go off to the side, and they actually 310 00:15:56,730 --> 00:15:58,680 said in front of me, because I don't 311 00:15:58,680 --> 00:16:02,070 think they realized that I wasn't a utility person, 312 00:16:02,070 --> 00:16:05,460 they're like, yeah, you just got to think sometimes, 313 00:16:05,460 --> 00:16:08,617 an explosion is the price of using gas. 314 00:16:08,617 --> 00:16:13,534 And like the kids are behind us playing in the playground. 315 00:16:13,534 --> 00:16:16,510 AUDIENCE: It wasn't a facetious comment, huh? 316 00:16:16,510 --> 00:16:18,899 PROFESSOR: No, it was an-- 317 00:16:18,899 --> 00:16:20,690 AUDIENCE: Like it comes with the territory? 318 00:16:20,690 --> 00:16:23,630 PROFESSOR: Yeah, and I mean, yeah, it 319 00:16:23,630 --> 00:16:25,950 was sort of, in front of the kids, 320 00:16:25,950 --> 00:16:28,192 I just thought that was really strange. 321 00:16:28,192 --> 00:16:33,012 AUDIENCE: So did they do something [INAUDIBLE]?? 322 00:16:33,012 --> 00:16:36,104 PROFESSOR: They did fix it after a while, what Bob said, 323 00:16:36,104 --> 00:16:38,594 but they didn't fix it at that point. 324 00:16:38,594 --> 00:16:40,260 AUDIENCE: That's the highest we've seen. 325 00:16:40,260 --> 00:16:44,790 PROFESSOR: Yeah, 1, 1, 1, it just exceeded 1, 1.2. 326 00:16:44,790 --> 00:16:47,686 So the gas company, so 2.2. 327 00:16:47,686 --> 00:16:52,650 OK, so this is too close to this tree to be good for this tree. 328 00:16:52,650 --> 00:16:57,810 And clearly this tree is not that old. 329 00:16:57,810 --> 00:16:59,640 How long ago did they put this in here, 330 00:16:59,640 --> 00:17:01,350 how much did it cost to put this in here? 331 00:17:01,350 --> 00:17:03,600 And now you've got a leak here. 332 00:17:03,600 --> 00:17:08,220 And this white paint, that's a sign of the gas company having 333 00:17:08,220 --> 00:17:12,250 been out here at some point to monitor. 334 00:17:12,250 --> 00:17:14,880 Here's the service line. 335 00:17:14,880 --> 00:17:17,432 So I don't know, I mean-- 336 00:17:17,432 --> 00:17:19,140 AUDIENCE: Sorry if I missed this earlier, 337 00:17:19,140 --> 00:17:20,849 but why does methane kill the tree? 338 00:17:20,849 --> 00:17:22,410 PROFESSOR: Oh, yeah, sorry. 339 00:17:22,410 --> 00:17:25,800 The methane, the natural gas has no oxygen in it. 340 00:17:25,800 --> 00:17:28,890 And the root systems need oxygen to metabolize, 341 00:17:28,890 --> 00:17:33,300 so you've got this plume of anoxic soil volume, 342 00:17:33,300 --> 00:17:35,015 and it kills the roots. 343 00:17:35,015 --> 00:17:36,390 AUDIENCE: So in fact, right here, 344 00:17:36,390 --> 00:17:39,000 isn't it the case that there could have been an older tree 345 00:17:39,000 --> 00:17:40,950 the same age as these tall ones that 346 00:17:40,950 --> 00:17:43,140 died and was replaced by this. 347 00:17:43,140 --> 00:17:47,190 And possibly it died because of methane leak. 348 00:17:47,190 --> 00:17:49,401 PROFESSOR: Yeah, I mean, it would 349 00:17:49,401 --> 00:17:51,900 be very interesting to find out what the history of this is, 350 00:17:51,900 --> 00:17:53,316 because this is I don't know, this 351 00:17:53,316 --> 00:17:55,680 is maybe two to three years old is 352 00:17:55,680 --> 00:18:01,090 my guess from the sampling from whatever it was planted. 353 00:18:01,090 --> 00:18:04,920 So OK, I'm not getting anything at the very surface here, 354 00:18:04,920 --> 00:18:09,140 but we definitely got some there. 355 00:18:09,140 --> 00:18:11,850 And that's two too close to this tree, because I mean, 356 00:18:11,850 --> 00:18:15,160 the root system is certainly going over there. 357 00:18:15,160 --> 00:18:17,160 Another really interesting thing, so it actually 358 00:18:17,160 --> 00:18:18,480 does come back to being-- 359 00:18:18,480 --> 00:18:22,651 so I'm a tree physiologist actually. 360 00:18:22,651 --> 00:18:24,150 That's what I'm suppose to be doing, 361 00:18:24,150 --> 00:18:25,524 that's why I got into this stuff. 362 00:18:25,524 --> 00:18:28,620 But it's interesting, because some trees have 363 00:18:28,620 --> 00:18:32,040 a vasculature that is called segmented, 364 00:18:32,040 --> 00:18:36,840 and some tree species have an integrated vascular structure. 365 00:18:36,840 --> 00:18:41,310 What that means is that some species, the roots on this side 366 00:18:41,310 --> 00:18:44,670 are connected to the pipes that run water on this side 367 00:18:44,670 --> 00:18:47,710 and are connected to the branches on the side. 368 00:18:47,710 --> 00:18:52,000 And then this side operates kind of like as a parallel path. 369 00:18:52,000 --> 00:18:54,450 Whereas other trees species like pine, 370 00:18:54,450 --> 00:18:59,330 a lot of the pine species, it's like whatever comes out of here 371 00:18:59,330 --> 00:19:02,130 or goes through here could have been from anywhere in the soil, 372 00:19:02,130 --> 00:19:05,290 it's integrated, OK, spatially integrated. 373 00:19:05,290 --> 00:19:09,960 So if the gas leak has some spatial pattern to it, 374 00:19:09,960 --> 00:19:13,020 you could see differences in where it shows up on the tree 375 00:19:13,020 --> 00:19:16,680 depending on the tree species and its vascular structure. 376 00:19:16,680 --> 00:19:18,470 Look at this, look how it's breaking off, 377 00:19:18,470 --> 00:19:20,900 like the twigs are just snapping. 378 00:19:20,900 --> 00:19:23,500 This tree is not in good, it's dried out. 379 00:19:23,500 --> 00:19:27,300 And so this is not, this tree is having problems. 380 00:19:27,300 --> 00:19:29,370 You can just, I mean, I'm not killing this tree, 381 00:19:29,370 --> 00:19:32,280 it's just like these tips are dead. 382 00:19:32,280 --> 00:19:35,390 They're not hydrated. 383 00:19:35,390 --> 00:19:37,800 AUDIENCE: Well, this one's OK. 384 00:19:37,800 --> 00:19:38,300 OK, 385 00:19:38,300 --> 00:19:41,900 PROFESSOR: Yeah, so these are OK over here. 386 00:19:41,900 --> 00:19:43,740 This side is not doing so good. 387 00:19:43,740 --> 00:19:44,480 So I don't know. 388 00:19:44,480 --> 00:19:46,438 AUDIENCE: So it's something that you envisioned 389 00:19:46,438 --> 00:19:52,652 citizen scientist doing like measuring for methane 390 00:19:52,652 --> 00:19:55,510 and trace the problem for their trees, 391 00:19:55,510 --> 00:19:58,210 and then reporting it to the city or reporting it-- 392 00:19:58,210 --> 00:20:00,370 PROFESSOR: Totally, yeah. 393 00:20:00,370 --> 00:20:04,040 And that's the whole idea behind making this available through 394 00:20:04,040 --> 00:20:07,000 heat by the Sierra Club, I'm on the executive committee 395 00:20:07,000 --> 00:20:12,020 of the Sierra Club, so I'm like promoting the Sierra Club. 396 00:20:12,020 --> 00:20:15,620 But they're making these things available for communities 397 00:20:15,620 --> 00:20:17,990 to do what we're doing, to use your nose, 398 00:20:17,990 --> 00:20:22,327 to use your eyes to find. 399 00:20:22,327 --> 00:20:24,410 People will walk by it's like, oh, I smell a leak, 400 00:20:24,410 --> 00:20:27,080 and then you can go and check this out and actually 401 00:20:27,080 --> 00:20:30,230 find out where it is, and then report it. 402 00:20:30,230 --> 00:20:33,320 You don't have to wait to report it if you smell a leak, 403 00:20:33,320 --> 00:20:35,220 you can and should report it. 404 00:20:35,220 --> 00:20:37,940 But it empowers you to find out more. 405 00:20:37,940 --> 00:20:44,630 And Mothers Out Front has been amazing in terms of also-- 406 00:20:44,630 --> 00:20:46,880 it's not just what they know, but when 407 00:20:46,880 --> 00:20:48,350 they plant that flag in the ground, 408 00:20:48,350 --> 00:20:51,380 it's showing everyone else that there's a leak here as well. 409 00:20:51,380 --> 00:20:54,140 So just essentially making the problem 410 00:20:54,140 --> 00:20:57,304 transparent to everyone. 411 00:20:57,304 --> 00:20:58,280 AUDIENCE: [INAUDIBLE]? 412 00:20:58,280 --> 00:21:02,030 PROFESSOR: So Mothers Out Front has had and maybe 413 00:21:02,030 --> 00:21:05,055 still do a campaign where there's a leak, 414 00:21:05,055 --> 00:21:06,725 they just plant a yellow flag, and it 415 00:21:06,725 --> 00:21:09,800 has a sniffing nose on it and it basically makes it clear 416 00:21:09,800 --> 00:21:11,090 that there's a leak there. 417 00:21:11,090 --> 00:21:14,150 AUDIENCE: We did in a concentrated time period, 418 00:21:14,150 --> 00:21:17,820 and then we collected the flags back again. 419 00:21:17,820 --> 00:21:22,490 But during that process, a lot of people talked with us 420 00:21:22,490 --> 00:21:26,330 and were reading the information that we left 421 00:21:26,330 --> 00:21:28,532 attached to the flag-- 422 00:21:28,532 --> 00:21:29,990 AUDIENCE: Did the utility companies 423 00:21:29,990 --> 00:21:32,420 respond to those flags at all per se? 424 00:21:32,420 --> 00:21:35,810 AUDIENCE: Not in any way that we know. 425 00:21:35,810 --> 00:21:37,830 Audrey might know a little bit more. 426 00:21:37,830 --> 00:21:41,670 We didn't do any measurements, we were just 427 00:21:41,670 --> 00:21:44,860 going from the mapping that had been done, 428 00:21:44,860 --> 00:21:50,046 and we were given points where there was more 429 00:21:50,046 --> 00:21:52,602 significant leakage going on. 430 00:21:52,602 --> 00:21:54,060 PROFESSOR: And so that was actually 431 00:21:54,060 --> 00:21:57,090 driven by information provided by the utilities. 432 00:21:57,090 --> 00:22:01,761 But like a follow on development of this could be-- 433 00:22:01,761 --> 00:22:05,790 'cause we know that the leak map provided by the utilities, as 434 00:22:05,790 --> 00:22:08,430 good as Audrey did to put them faithfully 435 00:22:08,430 --> 00:22:10,200 down where they were looking. 436 00:22:10,200 --> 00:22:12,510 The utilities get it wrong sometimes, 437 00:22:12,510 --> 00:22:14,140 or these missing leaks-- 438 00:22:14,140 --> 00:22:15,315 what are we calling them? 439 00:22:15,315 --> 00:22:16,565 AUDIENCE: Yeah, missing leaks. 440 00:22:16,565 --> 00:22:19,290 PROFESSOR: Missing leaks that have come off the books. 441 00:22:19,290 --> 00:22:23,280 And it doesn't seem like they like 15% of them 442 00:22:23,280 --> 00:22:27,840 came off like on December 31st, it doesn't make sense. 443 00:22:27,840 --> 00:22:31,000 So it's kind of auditing them as well. 444 00:22:31,000 --> 00:22:33,654 And this is just us being parked here, OK? 445 00:22:33,654 --> 00:22:35,820 So you can see it going up and down and up and down, 446 00:22:35,820 --> 00:22:40,140 and that again, is just the wind wafting this leak around. 447 00:22:40,140 --> 00:22:42,870 So it gives you an idea of the vagaries of the weather 448 00:22:42,870 --> 00:22:43,660 conditions. 449 00:22:43,660 --> 00:22:48,180 But you can see also that even when it goes down, I mean, 450 00:22:48,180 --> 00:22:50,910 the lowest it ever went here is like, I don't know, 451 00:22:50,910 --> 00:22:53,340 2.7 or maybe 3 or so. 452 00:22:53,340 --> 00:22:56,160 So it's obviously a leak. 453 00:22:56,160 --> 00:23:00,130 But depending on the conditions, I mean, we were up above 16, we 454 00:23:00,130 --> 00:23:02,460 we're down to like 3. 455 00:23:02,460 --> 00:23:04,840 And so if you drive a leak two different times, 456 00:23:04,840 --> 00:23:07,336 you're going to get two different peak readings. 457 00:23:07,336 --> 00:23:08,794 That's part of the thing that makes 458 00:23:08,794 --> 00:23:14,510 it difficult to estimate like really how big the leak is. 459 00:23:14,510 --> 00:23:17,430 This is still the Swiss Alps of leaks. 460 00:23:17,430 --> 00:23:18,610 OK, here's the school. 461 00:23:22,602 --> 00:23:24,600 AUDIENCE: What are you at? 462 00:23:24,600 --> 00:23:27,233 PROFESSOR: 2.4, 3.3, OK, so there's a leak right here 463 00:23:27,233 --> 00:23:29,510 at the school, 2.37. 464 00:23:29,510 --> 00:23:31,100 So when you see it dip down like that 465 00:23:31,100 --> 00:23:33,308 and then come back up like that, that's pretty clear. 466 00:23:33,308 --> 00:23:37,010 We're moving at a steady pace here, so got a leak here. 467 00:23:37,010 --> 00:23:38,700 I didn't pay attention to the trees. 468 00:23:38,700 --> 00:23:39,600 AUDIENCE: 4. 469 00:23:39,600 --> 00:23:41,350 PROFESSOR: 4, OK. 470 00:23:41,350 --> 00:23:45,920 Some young trees, patches. 471 00:23:45,920 --> 00:23:50,260 AUDIENCE: 3.8, 3.4, 2.9. 472 00:23:50,260 --> 00:23:52,325 PROFESSOR: OK, that tree [INAUDIBLE].. 473 00:23:56,080 --> 00:23:57,670 All right, so leaks there. 474 00:23:57,670 --> 00:23:59,104 9. 475 00:23:59,104 --> 00:23:59,997 We got 9. 476 00:23:59,997 --> 00:24:00,538 AUDIENCE: 12. 477 00:24:00,538 --> 00:24:01,494 PROFESSOR: 11. 478 00:24:01,494 --> 00:24:03,265 AUDIENCE: 11. 479 00:24:03,265 --> 00:24:04,640 PROFESSOR: You want to pull over? 480 00:24:04,640 --> 00:24:05,265 AUDIENCE: Yeah. 481 00:24:05,265 --> 00:24:06,428 PROFESSOR: OK. 482 00:24:06,428 --> 00:24:08,660 AUDIENCE: And you see the yellow markings everywhere, 483 00:24:08,660 --> 00:24:11,200 and that's always gas, the yellow is gas. 484 00:24:11,200 --> 00:24:15,370 PROFESSOR: Yeah, yellow always refers to gas. 485 00:24:15,370 --> 00:24:18,280 Blue is water. 486 00:24:18,280 --> 00:24:21,900 PROFESSOR: So it's like you see stuff every time that's 487 00:24:21,900 --> 00:24:22,900 just a little different. 488 00:24:22,900 --> 00:24:26,090 Like I don't know if I've ever seen a marking like right 489 00:24:26,090 --> 00:24:30,560 on a curbstone like that for [INAUDIBLE].. 490 00:24:30,560 --> 00:24:33,609 I guess that's the arrow [INAUDIBLE].. 491 00:24:33,609 --> 00:24:35,650 PROFESSOR: Yeah, but there seems to one here too, 492 00:24:35,650 --> 00:24:39,246 so are there two 12 inch mains running down the street 493 00:24:39,246 --> 00:24:40,440 that way underneath us. 494 00:24:40,440 --> 00:24:42,460 PROFESSOR: You have multiple mains. 495 00:24:42,460 --> 00:24:45,380 Oh, I think of bracketing it here. 496 00:24:45,380 --> 00:24:47,250 So you can see the two yellow lines. 497 00:24:47,250 --> 00:24:50,360 But here it is, 12 inch cast iron. 498 00:24:50,360 --> 00:24:52,800 Cast iron is the old leaky stuff. 499 00:24:52,800 --> 00:24:58,000 It's the most leak prone, most prevalent leak prone pipe. 500 00:24:58,000 --> 00:24:59,714 PROFESSOR: So with cast iron, they 501 00:24:59,714 --> 00:25:01,130 way they originally did it is they 502 00:25:01,130 --> 00:25:04,550 put jute, which is sort of a grass, between the two joint-- 503 00:25:04,550 --> 00:25:05,840 to close the joints. 504 00:25:05,840 --> 00:25:10,020 And then as gas got less humid, because they 505 00:25:10,020 --> 00:25:14,410 decreased the humidity of the gas, that jute dried out. 506 00:25:14,410 --> 00:25:18,160 And so they're basically almost all cast iron 507 00:25:18,160 --> 00:25:22,810 has problems, every 12 feet, because of that. 508 00:25:22,810 --> 00:25:23,914 AUDIENCE: Wow. 509 00:25:23,914 --> 00:25:26,736 PROFESSOR: Let's see if we get anything out of here. 510 00:25:26,736 --> 00:25:29,157 PROFESSOR: Nathan and Bob Ackley went out to-- 511 00:25:29,157 --> 00:25:30,990 PROFESSOR: All that work and we got nothing. 512 00:25:33,750 --> 00:25:35,410 So it's not [INAUDIBLE]. 513 00:25:39,455 --> 00:25:44,534 Now these are drill holes, so kind of push it there 514 00:25:44,534 --> 00:25:45,700 and see if you get anything. 515 00:25:45,700 --> 00:25:49,440 Just hold it down, you'll hear it slow down, 516 00:25:49,440 --> 00:25:54,240 the pump slow down if you push it too hard. 517 00:25:54,240 --> 00:25:55,440 OK, nothing there. 518 00:25:55,440 --> 00:25:58,649 So drill holes are for the gas company when they come out. 519 00:26:12,230 --> 00:26:15,300 OK, let's come out quick and try these. 520 00:26:15,300 --> 00:26:18,630 All right, so let's go out here and let's just test-- 521 00:26:18,630 --> 00:26:22,460 let's stick it in one of these things real quick. 522 00:26:22,460 --> 00:26:25,460 Leave it in for about 10 seconds. 523 00:26:25,460 --> 00:26:28,740 And maybe someone can make sure we don't get hit. 524 00:26:28,740 --> 00:26:30,730 Keep an eye out. 525 00:26:30,730 --> 00:26:33,350 AUDIENCE: OK, there we go. 526 00:26:33,350 --> 00:26:39,774 40.4. 527 00:26:39,774 --> 00:26:40,940 PROFESSOR: Keep it in there. 528 00:26:40,940 --> 00:26:43,644 Keep it in there. 529 00:26:43,644 --> 00:26:44,560 AUDIENCE: Cars coming. 530 00:26:44,560 --> 00:26:46,060 PROFESSOR: All right, we can get up. 531 00:26:46,060 --> 00:26:48,890 OK, so definitely gas in there. 532 00:26:48,890 --> 00:26:54,620 OK, so yeah, we didn't really find-- 533 00:26:54,620 --> 00:26:58,385 we found the leak, but we didn't find any large concentration. 534 00:26:58,385 --> 00:27:00,260 AUDIENCE: It might have been a little further 535 00:27:00,260 --> 00:27:02,090 down the block, the scent. 536 00:27:02,090 --> 00:27:05,090 PROFESSOR: I mean, it's all along this block, so yeah. 537 00:27:05,090 --> 00:27:07,190 This is relatively new, right, look at the line 538 00:27:07,190 --> 00:27:10,170 where the new paving was. 539 00:27:10,170 --> 00:27:13,140 This intersection was redone with a new everything, 540 00:27:13,140 --> 00:27:13,830 we got gas. 541 00:27:13,830 --> 00:27:20,330 So this is an example of a lost opportunity. 542 00:27:20,330 --> 00:27:24,610 PROFESSOR: With MAPC, he did a study to sort of figure 543 00:27:24,610 --> 00:27:28,840 out how much municipalities and gas companies could 544 00:27:28,840 --> 00:27:31,540 save by doing sort of more integrated infrastructure 545 00:27:31,540 --> 00:27:33,170 repair and not screwing up like this. 546 00:27:33,170 --> 00:27:34,640 AUDIENCE: Here comes a, yep. 547 00:27:34,640 --> 00:27:38,620 PROFESSOR: And it was like $1 billion. 548 00:27:38,620 --> 00:27:42,910 You can check it out and fixourpipes.org. 549 00:27:42,910 --> 00:27:45,480 It's a really beautiful website. 550 00:27:45,480 --> 00:27:48,930 PROFESSOR: So it was just a little bit. 551 00:27:48,930 --> 00:27:54,729 But there is gas, I mean, so that's not good. 552 00:27:54,729 --> 00:27:56,270 PROFESSOR: So you can sort of imagine 553 00:27:56,270 --> 00:27:58,490 like all the infrastructure underneath, both the gas 554 00:27:58,490 --> 00:28:00,830 pipes and the electric and the water mains and stuff 555 00:28:00,830 --> 00:28:03,150 like that, as well as the paving. 556 00:28:03,150 --> 00:28:05,930 And the paving alone in Massachusetts 557 00:28:05,930 --> 00:28:10,280 I think is $600,000 on average per mile. 558 00:28:10,280 --> 00:28:13,720 So it's just expense layered on expense on expense. 559 00:28:13,720 --> 00:28:17,160 And so if you fix anything, if you cut into the pavement 560 00:28:17,160 --> 00:28:20,864 for any reason, you should just fix all of it at the same time. 561 00:28:20,864 --> 00:28:22,780 'Cause otherwise, it's like operating 562 00:28:22,780 --> 00:28:25,330 on somebody's appendix and finding a broken artery, 563 00:28:25,330 --> 00:28:27,900 and be like, oh, whatever. 564 00:28:27,900 --> 00:28:30,790 Forget that, we'll take care of that some other time. 565 00:28:30,790 --> 00:28:32,640 Not our responsibility.