WEBVTT 00:00:01.680 --> 00:00:04.080 The following content is provided under a Creative 00:00:04.080 --> 00:00:05.620 Commons license. 00:00:05.620 --> 00:00:07.920 Your support will help MIT OpenCourseWare 00:00:07.920 --> 00:00:12.280 continue to offer high quality educational resources for free. 00:00:12.280 --> 00:00:14.910 To make a donation or view additional materials 00:00:14.910 --> 00:00:18.870 from hundreds of MIT courses, visit MIT OpenCourseWare 00:00:18.870 --> 00:00:20.020 at ocw.mit.edu. 00:00:25.878 --> 00:00:29.320 PROFESSOR: I'll do the Vanna White thing. 00:00:29.320 --> 00:00:34.340 So this sucks in air here, and inside, 00:00:34.340 --> 00:00:39.040 57% of methane or other combustible gases in it. 00:00:39.040 --> 00:00:43.330 And it sucks in about I think half liter a minute. 00:00:43.330 --> 00:00:45.900 And so you can get a percent gas in the air. 00:00:45.900 --> 00:00:50.200 And so luckily, at the moment, there's probably 0% methane. 00:00:50.200 --> 00:00:53.410 AUDIENCE: Is that what gas companies quickly 00:00:53.410 --> 00:00:54.160 use to find leaks? 00:00:54.160 --> 00:00:55.660 PROFESSOR: Yeah, yeah, they normally 00:00:55.660 --> 00:00:56.750 have a big probe on it. 00:00:56.750 --> 00:01:00.005 And what they do is they take bang bar, which 00:01:00.005 --> 00:01:02.130 is like a big stick and they stick it in the ground 00:01:02.130 --> 00:01:04.060 until they get a hole, and then they 00:01:04.060 --> 00:01:07.250 stick this with a probe on it, suck air in 00:01:07.250 --> 00:01:10.100 and figure out what the percent gas is in the soil. 00:01:10.100 --> 00:01:12.120 Then they know by where the highest percentage 00:01:12.120 --> 00:01:13.175 is in the soil. 00:01:13.175 --> 00:01:15.300 They figure, OK, that's probably where the leak is, 00:01:15.300 --> 00:01:18.180 and they start digging there. 00:01:18.180 --> 00:01:25.068 So it's a really simple and fantastic tool. 00:01:25.068 --> 00:01:27.550 CGI, yeah, combustible gas indicator. 00:01:27.550 --> 00:01:32.850 PROFESSOR: And right here is where the inlet is, 00:01:32.850 --> 00:01:34.350 OK, just off of here. 00:01:34.350 --> 00:01:39.000 We do this-- it's better to do it than in the back bumper, 00:01:39.000 --> 00:01:44.010 because there can be some exhaust contamination. 00:01:44.010 --> 00:01:49.740 Actually, well, two cars, we've tested it, do not interfere, 00:01:49.740 --> 00:01:51.720 but this is a little bit of an old van. 00:01:51.720 --> 00:01:55.520 So sometimes-- I mean, it passed the emissions test, 00:01:55.520 --> 00:02:00.370 but still there can be some contamination. 00:02:00.370 --> 00:02:04.030 That's why when we stopped, sometimes you'll 00:02:04.030 --> 00:02:07.600 get some measurements, but when you're moving forward 00:02:07.600 --> 00:02:11.710 and the wind is upstream, you know you're getting readings. 00:02:11.710 --> 00:02:14.440 This is the methane reading that analyzers 00:02:14.440 --> 00:02:16.720 are reading right now. 00:02:16.720 --> 00:02:20.310 So it's anything below 2, it's right now, 00:02:20.310 --> 00:02:23.690 1.96 is pretty clean. 00:02:23.690 --> 00:02:25.660 There's no leak where we are right now. 00:02:25.660 --> 00:02:31.510 So if it's under 2, you know we're in a place with no leak. 00:02:31.510 --> 00:02:36.720 And even if it creeps up over 2, if it's like 2.01, 2.02, 00:02:36.720 --> 00:02:40.330 that's not really indicative of a leak. 00:02:40.330 --> 00:02:44.020 But if you see it go up to like 2, 00:02:44.020 --> 00:02:47.005 your eyes can tell you in time that oh, it 00:02:47.005 --> 00:02:50.050 seems to be going up pretty rapidly here. 00:02:50.050 --> 00:02:52.765 And so you'll see it maybe go for 2.3 sometimes, 00:02:52.765 --> 00:02:54.460 and then drop back down. 00:02:54.460 --> 00:02:56.380 And that's kind of unusual. 00:02:56.380 --> 00:02:59.002 That's like, OK, there's probably something around here. 00:02:59.002 --> 00:03:00.460 And then every once in a while, you 00:03:00.460 --> 00:03:04.780 might see something that goes up further, 3, 3 and 1/2, 00:03:04.780 --> 00:03:08.710 and those are like definite leaks. 00:03:08.710 --> 00:03:11.490 AUDIENCE: What's the highest number you've ever seen? 00:03:11.490 --> 00:03:14.560 PROFESSOR: Well, in DC, we got I think very 00:03:14.560 --> 00:03:17.350 near to 100 parts per million. 00:03:17.350 --> 00:03:19.450 And that's in the air that we're breathing, 00:03:19.450 --> 00:03:22.040 so it's not explosive at that level. 00:03:22.040 --> 00:03:26.260 But it's like 50 times more than the background value. 00:03:26.260 --> 00:03:28.300 AUDIENCE: So 2 is baseline kind of background. 00:03:28.300 --> 00:03:30.008 PROFESSOR: Yeah, yeah, you can consider 2 00:03:30.008 --> 00:03:32.260 to be a baseline level. 00:03:32.260 --> 00:03:41.980 Now it's like CO2, well, it used to be 280 parts per million, 00:03:41.980 --> 00:03:44.320 and now it's like over 400. 00:03:44.320 --> 00:03:48.710 So 2 parts per million methane is the new normal. 00:03:48.710 --> 00:03:52.450 I mean it was 0.7 parts per million, preindustrial. 00:03:52.450 --> 00:03:55.090 So I would like to point that out 00:03:55.090 --> 00:03:59.180 that are our normal baseline is very abnormal. 00:03:59.180 --> 00:04:01.680 So we're going up about that with leaks. 00:04:01.680 --> 00:04:04.270 Now this is a timeline here, this graph, 00:04:04.270 --> 00:04:08.590 and you can see as I came in here, we did get 6, 7, 00:04:08.590 --> 00:04:10.540 we got a few leaks here. 00:04:10.540 --> 00:04:12.820 And that was right at the Allston/Brighton tolls 00:04:12.820 --> 00:04:15.610 coming down off of the Mass Pike. 00:04:15.610 --> 00:04:18.820 There's a leak there. 00:04:18.820 --> 00:04:21.000 AUDIENCE: So what happens in terms the reporting 00:04:21.000 --> 00:04:23.650 that or following up with it? 00:04:23.650 --> 00:04:26.200 PROFESSOR: So we don't have any evidence, 00:04:26.200 --> 00:04:28.270 but based on driving by. 00:04:28.270 --> 00:04:33.550 We can't say whether it's a green one hazardous leak, 00:04:33.550 --> 00:04:38.530 a grade two, or a grade three so-called non-hazardous leak. 00:04:38.530 --> 00:04:42.040 So I don't feel obligated that each 00:04:42.040 --> 00:04:44.590 what we see that OK, we got to call the gas company. 00:04:44.590 --> 00:04:48.160 First of all, they do know about these leaks. 00:04:48.160 --> 00:04:53.900 They know-- to a large degree where they are. 00:04:53.900 --> 00:04:56.680 But if we get out, and we could, because we have the CGI. 00:04:56.680 --> 00:04:59.770 If we decide to get out and poke around and look through it, 00:04:59.770 --> 00:05:03.520 and we find evidence that it is like a grade one, 00:05:03.520 --> 00:05:07.896 then that's when I feel obligated to call the leak in. 00:05:07.896 --> 00:05:09.670 'Cause it's like we have knowledge 00:05:09.670 --> 00:05:14.070 that something seems to be unsafe, 00:05:14.070 --> 00:05:15.733 and so then we call it in. 00:05:15.733 --> 00:05:16.233 Yep? 00:05:16.233 --> 00:05:17.732 AUDIENCE: Is there a clear indicator 00:05:17.732 --> 00:05:19.180 when it's a grade one? 00:05:19.180 --> 00:05:20.740 PROFESSOR: This machine is not going 00:05:20.740 --> 00:05:23.860 to be able to tell us whether there's a grade one, a grade 00:05:23.860 --> 00:05:27.230 explosive hazard, grade two, or grade three. 00:05:27.230 --> 00:05:34.510 And that's because you can have big leaks with lots of gas 00:05:34.510 --> 00:05:38.320 coming out that are not explosive hazards. 00:05:38.320 --> 00:05:41.480 Like the Porter Ranch gas leak in LA, 00:05:41.480 --> 00:05:44.800 Audrey makes this point a lot, it was technically 00:05:44.800 --> 00:05:47.090 a grade three non-hazardous leak, 00:05:47.090 --> 00:05:49.970 'cause it wasn't going to explode. 00:05:49.970 --> 00:05:52.180 And it wasn't that close to the neighborhood, 00:05:52.180 --> 00:05:54.610 it was like a quarter mile away from the neighborhood. 00:05:54.610 --> 00:05:57.700 So it's an indication that that grading scheme 00:05:57.700 --> 00:06:00.430 is only a single variable grading scheme. 00:06:00.430 --> 00:06:04.315 And explosion and hazard is a big deal. 00:06:04.315 --> 00:06:06.440 There's no doubt about that, and no one wants that. 00:06:06.440 --> 00:06:12.070 So what the grading scheme has to incorporate 00:06:12.070 --> 00:06:13.510 the amount of the flux. 00:06:13.510 --> 00:06:15.910 There is a GPS on this roof right now, 00:06:15.910 --> 00:06:18.185 and it's plugged into the back of the machine, 00:06:18.185 --> 00:06:22.375 and the data file that comes out is already integrated with GPS 00:06:22.375 --> 00:06:23.765 with the time stamp. 00:06:23.765 --> 00:06:25.040 Straight? 00:06:25.040 --> 00:06:27.554 AUDIENCE: Left, if we can, yep. 00:06:30.500 --> 00:06:34.250 So what are the objectives for today? 00:06:34.250 --> 00:06:40.680 Is it just to see how methane is measured, 00:06:40.680 --> 00:06:44.600 or are we trying to answer any particular questions? 00:06:44.600 --> 00:06:48.140 PROFESSOR: So what we call this is a gas leak safari. 00:06:48.140 --> 00:06:50.480 So one of the objectives-- 00:06:50.480 --> 00:06:55.590 OK, here we are, 2, 3, 2, 3, so there's something there. 00:06:59.220 --> 00:07:02.090 So just to educate and to show first 00:07:02.090 --> 00:07:06.560 of all what this process is of mapping the gas leaks. 00:07:06.560 --> 00:07:10.160 I think that we're going to places that we have surveyed 00:07:10.160 --> 00:07:15.530 in the past, Audrey and Heat did the study now, two years ago, 00:07:15.530 --> 00:07:17.810 is it? 00:07:17.810 --> 00:07:19.334 But things change. 00:07:19.334 --> 00:07:20.500 AUDIENCE: Take a right here. 00:07:20.500 --> 00:07:22.430 PROFESSOR: Right on Portland. 00:07:22.430 --> 00:07:26.634 2.1, 2.1, OK, here we have something, 2.1. 00:07:26.634 --> 00:07:28.050 So there's something here I think. 00:07:28.050 --> 00:07:28.633 AUDIENCE: 2.3. 00:07:28.633 --> 00:07:29.270 AUDIENCE: 2.5. 00:07:29.270 --> 00:07:29.862 2.7. 00:07:29.862 --> 00:07:31.320 PROFESSOR: OK, yeah, read them out. 00:07:31.320 --> 00:07:32.980 AUDIENCE: 2.8. 00:07:32.980 --> 00:07:39.082 PROFESSOR: OK, so there's a leak here in this facility. 00:07:39.082 --> 00:07:41.537 AUDIENCE: Portland and Main. 00:07:41.537 --> 00:07:43.010 AUDIENCE: So that's at 2.3. 00:07:43.010 --> 00:07:47.066 Oh, 3.3, well, 4.4, 4.4. 00:07:47.066 --> 00:07:48.064 AUDIENCE: 4.2. 00:07:48.064 --> 00:07:49.635 3.8. 00:07:49.635 --> 00:07:51.010 PROFESSOR: So you can see there's 00:07:51.010 --> 00:07:53.210 the spike on the leading edge. 00:07:57.210 --> 00:07:57.710 Right? 00:08:00.290 --> 00:08:06.530 It's really as you can imagine, as any lay person can imagine, 00:08:06.530 --> 00:08:09.610 the vagaries of wind are going to the plume. 00:08:09.610 --> 00:08:12.500 The plume is coming out of wherever it can come out. 00:08:12.500 --> 00:08:14.780 I could come out of a man hole slot-- 00:08:14.780 --> 00:08:15.454 straight on? 00:08:15.454 --> 00:08:16.370 AUDIENCE: Straight on. 00:08:16.370 --> 00:08:19.220 PROFESSOR: It could come out of the soil. 00:08:19.220 --> 00:08:21.990 A leak is going to to just find whatever parallel 00:08:21.990 --> 00:08:24.590 pathways it can get out. 00:08:24.590 --> 00:08:26.750 And so you can imagine, at the surface 00:08:26.750 --> 00:08:31.760 there's some kind of profile of this stuff coming out. 00:08:31.760 --> 00:08:35.059 And then the wind's going to carry it and blow it around. 00:08:35.059 --> 00:08:40.309 And so that makes it a little tough. 00:08:40.309 --> 00:08:43.490 We can't really pinpoint exactly where 00:08:43.490 --> 00:08:45.220 it's coming out of the ground. 00:08:45.220 --> 00:08:48.000 We can know when we have driven by it. 00:08:48.000 --> 00:08:50.150 There's a leak in this vicinity, and I would always 00:08:50.150 --> 00:08:54.140 say within 50 to 100 feet of where 00:08:54.140 --> 00:08:57.660 we measured it is probably part of the source coming 00:08:57.660 --> 00:08:59.030 on the ground. 00:08:59.030 --> 00:09:03.480 But to actually really pinpoint where the pipeline leak is 00:09:03.480 --> 00:09:06.480 would require stopping, getting out, and using the instrument 00:09:06.480 --> 00:09:10.290 that Audrey has as well as maybe some other instruments, 00:09:10.290 --> 00:09:15.950 handheld snippers to really find out where it's coming out. 00:09:15.950 --> 00:09:21.140 What you're realizing right now that makes it like discreet 00:09:21.140 --> 00:09:26.030 when we see a leak, if you look at this timeline here, 00:09:26.030 --> 00:09:29.870 this trace, you can see there's a lot of flat 00:09:29.870 --> 00:09:33.680 and then some fairly well resolved spikes. 00:09:33.680 --> 00:09:38.450 And so it's not very ambiguous when you get 00:09:38.450 --> 00:09:40.820 an elevated anomalous reading. 00:09:40.820 --> 00:09:43.940 It's like, oh, there's one, there's one, there's one. 00:09:43.940 --> 00:09:46.450 Here's a couple that are small, but they really 00:09:46.450 --> 00:09:50.190 need to go very clearly from the back ground. 00:09:50.190 --> 00:09:53.300 So there's not that much ambiguity about like, well, 00:09:53.300 --> 00:09:57.525 is this kind of giant blob a leak or not? 00:09:57.525 --> 00:10:02.205 They're well resolved spikes in time and space. 00:10:02.205 --> 00:10:03.580 AUDIENCE: What's the biggest leak 00:10:03.580 --> 00:10:06.205 you've seen in the Boston area? 00:10:06.205 --> 00:10:09.550 PROFESSOR: Maybe like 40 or 50 parts per million in the air. 00:10:09.550 --> 00:10:11.811 AUDIENCE: Where was that? 00:10:11.811 --> 00:10:14.310 PROFESSOR: Well, a couple of places that were close to that. 00:10:14.310 --> 00:10:21.700 One was Sullivan Square, Rutherford Street 00:10:21.700 --> 00:10:24.760 in Charles Town, kind of on the Somerville Charles Town 00:10:24.760 --> 00:10:26.480 border, the giant rotary. 00:10:26.480 --> 00:10:27.210 AUDIENCE: Yeah. 00:10:27.210 --> 00:10:28.960 PROFESSOR: I mean, we could go over there, 00:10:28.960 --> 00:10:30.250 there is a big leak there. 00:10:30.250 --> 00:10:33.313 And then Nonantum Road between kind of Watertown and Newton. 00:10:33.313 --> 00:10:37.248 2.2, 2.3, OK, so there's something here, OK. 00:10:37.248 --> 00:10:39.470 2.3, OK, so we've got, 2.5. 00:10:39.470 --> 00:10:40.782 AUDIENCE: 2.5. 00:10:40.782 --> 00:10:41.674 AUDIENCE: 2.8. 00:10:41.674 --> 00:10:42.803 3. 00:10:42.803 --> 00:10:43.610 3.2. 00:10:43.610 --> 00:10:45.482 4.8. 00:10:45.482 --> 00:10:46.450 AUDIENCE: 6. 00:10:46.450 --> 00:10:47.980 AUDIENCE: Oh boy. 00:10:47.980 --> 00:10:48.817 Oh boy. 00:10:48.817 --> 00:10:49.400 AUDIENCE: 5.3. 00:10:49.400 --> 00:10:52.220 PROFESSOR: So I mean, we could get out and take a break 00:10:52.220 --> 00:10:54.230 and find it if you wanted on this one. 00:10:54.230 --> 00:10:55.520 It's kind of quiet. 00:10:55.520 --> 00:10:58.340 This is definitely a much blunter instrument 00:10:58.340 --> 00:10:59.690 than that one. 00:10:59.690 --> 00:11:05.640 And it's made to find out like percent level, 50%, 10%, 00:11:05.640 --> 00:11:07.146 not parts per million. 00:11:07.146 --> 00:11:09.790 OK, so this is now when you want to find out 00:11:09.790 --> 00:11:14.198 where is it coming out at, OK? 00:11:14.198 --> 00:11:18.272 The professionals right now would have this bar, 00:11:18.272 --> 00:11:19.230 it's called a bang bar. 00:11:19.230 --> 00:11:22.140 It's like one of those construction pile drivers, 00:11:22.140 --> 00:11:24.160 it's like a handheld version of that. 00:11:24.160 --> 00:11:28.000 And you would find out, maybe right here, you'd 00:11:28.000 --> 00:11:32.800 like slam it down maybe up to a meter. 00:11:32.800 --> 00:11:34.280 And this would have a longer thing, 00:11:34.280 --> 00:11:35.446 and you'd stick it in there. 00:11:35.446 --> 00:11:40.510 Now I don't do that, because I'm not certified to do that, 00:11:40.510 --> 00:11:42.820 and I don't want to puncture any gas lines 00:11:42.820 --> 00:11:44.590 and create an explosion. 00:11:44.590 --> 00:11:49.720 So what I do is I just kind of do like this, 00:11:49.720 --> 00:11:53.220 and sometimes I'll use like a screwdriver or just a stick 00:11:53.220 --> 00:11:56.440 even, and kind of-- 00:11:56.440 --> 00:11:58.870 this is right at the surface-- 00:11:58.870 --> 00:12:00.550 and poke around. 00:12:00.550 --> 00:12:04.740 So actually look, there is something, point 0.2. 00:12:04.740 --> 00:12:08.260 Now the fact, 0.25%. 00:12:08.260 --> 00:12:16.250 So 0.25% is, let's see, 1% is 10,000 parts per million, 00:12:16.250 --> 00:12:19.020 right, 1% is 10, 000 parts per million. 00:12:19.020 --> 00:12:22.680 This is 8,500 parts per million right now-- 00:12:22.680 --> 00:12:24.960 0.85, 0.9. 00:12:24.960 --> 00:12:29.040 OK, so the thing is that this is right at the surface. 00:12:29.040 --> 00:12:32.340 If I was down even probably that much, 00:12:32.340 --> 00:12:35.590 it would probably be I don't know 15%, 20%. 00:12:35.590 --> 00:12:38.940 And if we went down a little further, this could be 90% gas. 00:12:38.940 --> 00:12:44.750 See this is 0.25. 00:12:44.750 --> 00:12:46.370 Yeah, so about the same. 00:12:46.370 --> 00:12:50.300 I'm just like about that far in. 00:12:50.300 --> 00:12:54.430 So this is an indication that there's definitely a leak here. 00:12:54.430 --> 00:12:57.140 And it's no mistake we got the 15 parts per million 00:12:57.140 --> 00:13:00.260 in the kind of air that we're breathing. 00:13:00.260 --> 00:13:03.020 So now let's look around for just infrastructure. 00:13:03.020 --> 00:13:07.160 Let's see I mean, that was a very arbitrary choice 00:13:07.160 --> 00:13:07.970 of a place to look. 00:13:07.970 --> 00:13:10.940 It's just we got out, we're here. 00:13:10.940 --> 00:13:13.500 But now I want to see like, OK, where is the gas line? 00:13:13.500 --> 00:13:15.800 AUDIENCE: And all that. 00:13:15.800 --> 00:13:20.110 PROFESSOR: That could be a vestige of a gas leak marking. 00:13:20.110 --> 00:13:23.240 And this big patch has been for some purpose, 00:13:23.240 --> 00:13:24.950 I don't know if it was a gas line. 00:13:24.950 --> 00:13:26.930 I see some more yellow paint out here. 00:13:29.870 --> 00:13:32.902 OK, so this is -- 00:13:32.902 --> 00:13:37.040 OK, yeah, always be very careful with the cars of course. 00:13:37.040 --> 00:13:42.920 So this is a service line coming off of the main, OK? 00:13:42.920 --> 00:13:47.960 So service lines going this way, mains generally going that way. 00:13:47.960 --> 00:13:50.480 Mains can be at an angle, they can 00:13:50.480 --> 00:13:55.406 be running under the sidewalk, so anything can really happen. 00:13:55.406 --> 00:13:56.780 AUDIENCE: So were mains laid down 00:13:56.780 --> 00:13:59.930 before the streets were gridded or something or what? 00:13:59.930 --> 00:14:01.809 PROFESSOR: Or sometimes afterwards. 00:14:01.809 --> 00:14:03.350 AUDIENCE: OK, but if it's afterwards, 00:14:03.350 --> 00:14:05.070 I'm going to assume that there-- configures to the street. 00:14:05.070 --> 00:14:07.670 PROFESSOR: They probably would do it running that way 00:14:07.670 --> 00:14:08.810 if it was done afterwards. 00:14:08.810 --> 00:14:09.757 AUDIENCE: OK. 00:14:09.757 --> 00:14:11.465 PROFESSOR: This is an electrical manhole. 00:14:15.470 --> 00:14:18.100 The gas can come in any-- 00:14:18.100 --> 00:14:19.700 it can seep in anywhere. 00:14:19.700 --> 00:14:23.330 So 0.25, OK, so gas in there. 00:14:23.330 --> 00:14:27.470 All right, so we did this. 00:14:33.050 --> 00:14:37.150 OK so, all right, so there's definitely gas in here. 00:14:37.150 --> 00:14:39.380 That's very, very clear. 00:14:39.380 --> 00:14:40.970 I mean, if you really wanted to, you 00:14:40.970 --> 00:14:42.770 could smell, and smell the gas, but I'm not 00:14:42.770 --> 00:14:45.410 going to recommend that. 00:14:45.410 --> 00:14:47.830 But this is not an explosive thresh hold. 00:14:47.830 --> 00:14:51.620 So I don't feel like, back off, don't smoke or whatever. 00:14:51.620 --> 00:14:57.450 Well, don't smoke, but if it were 4%, 00:14:57.450 --> 00:15:01.030 then that would be a grade one explosive hazard, OK? 00:15:01.030 --> 00:15:03.460 And we would call it in, and they 00:15:03.460 --> 00:15:06.750 would come out immediately, well, within a half hour or so. 00:15:06.750 --> 00:15:10.000 AUDIENCE: And again, 4% is what on that readout? 00:15:10.000 --> 00:15:12.380 PROFESSOR: 40,000 parts per million. 00:15:12.380 --> 00:15:15.500 4% is equal to 40,000 parts per million. 00:15:15.500 --> 00:15:19.270 So if the 4.0, that's 40,000 parts per million. 00:15:19.270 --> 00:15:21.760 And that's the lower explosion threshold, 00:15:21.760 --> 00:15:25.160 the higher explosion threshold is about 15% gas. 00:15:25.160 --> 00:15:28.420 If it gets above that, there's not enough oxygen 00:15:28.420 --> 00:15:29.769 for it to explode. 00:15:29.769 --> 00:15:31.560 PROFESSOR: All right, where little kids are 00:15:31.560 --> 00:15:33.685 like playing in the playground, there's a grade one 00:15:33.685 --> 00:15:36.540 leak under a manhole, we call it in, 00:15:36.540 --> 00:15:39.270 and these two guys from Evershore 00:15:39.270 --> 00:15:43.600 arrive, and they don't even have like a bang bar, 00:15:43.600 --> 00:15:47.358 and they didn't have the right instrumentation to do anything. 00:15:49.920 --> 00:15:52.200 So we pop open the manhole for them. 00:15:52.200 --> 00:15:54.855 And they look and they're like, yeah. 00:15:54.855 --> 00:15:56.730 Then we go off to the side, and they actually 00:15:56.730 --> 00:15:58.680 said in front of me, because I don't 00:15:58.680 --> 00:16:02.070 think they realized that I wasn't a utility person, 00:16:02.070 --> 00:16:05.460 they're like, yeah, you just got to think sometimes, 00:16:05.460 --> 00:16:08.617 an explosion is the price of using gas. 00:16:08.617 --> 00:16:13.534 And like the kids are behind us playing in the playground. 00:16:13.534 --> 00:16:16.510 AUDIENCE: It wasn't a facetious comment, huh? 00:16:16.510 --> 00:16:18.899 PROFESSOR: No, it was an-- 00:16:18.899 --> 00:16:20.690 AUDIENCE: Like it comes with the territory? 00:16:20.690 --> 00:16:23.630 PROFESSOR: Yeah, and I mean, yeah, it 00:16:23.630 --> 00:16:25.950 was sort of, in front of the kids, 00:16:25.950 --> 00:16:28.192 I just thought that was really strange. 00:16:28.192 --> 00:16:33.012 AUDIENCE: So did they do something [INAUDIBLE]?? 00:16:33.012 --> 00:16:36.104 PROFESSOR: They did fix it after a while, what Bob said, 00:16:36.104 --> 00:16:38.594 but they didn't fix it at that point. 00:16:38.594 --> 00:16:40.260 AUDIENCE: That's the highest we've seen. 00:16:40.260 --> 00:16:44.790 PROFESSOR: Yeah, 1, 1, 1, it just exceeded 1, 1.2. 00:16:44.790 --> 00:16:47.686 So the gas company, so 2.2. 00:16:47.686 --> 00:16:52.650 OK, so this is too close to this tree to be good for this tree. 00:16:52.650 --> 00:16:57.810 And clearly this tree is not that old. 00:16:57.810 --> 00:16:59.640 How long ago did they put this in here, 00:16:59.640 --> 00:17:01.350 how much did it cost to put this in here? 00:17:01.350 --> 00:17:03.600 And now you've got a leak here. 00:17:03.600 --> 00:17:08.220 And this white paint, that's a sign of the gas company having 00:17:08.220 --> 00:17:12.250 been out here at some point to monitor. 00:17:12.250 --> 00:17:14.880 Here's the service line. 00:17:14.880 --> 00:17:17.432 So I don't know, I mean-- 00:17:17.432 --> 00:17:19.140 AUDIENCE: Sorry if I missed this earlier, 00:17:19.140 --> 00:17:20.849 but why does methane kill the tree? 00:17:20.849 --> 00:17:22.410 PROFESSOR: Oh, yeah, sorry. 00:17:22.410 --> 00:17:25.800 The methane, the natural gas has no oxygen in it. 00:17:25.800 --> 00:17:28.890 And the root systems need oxygen to metabolize, 00:17:28.890 --> 00:17:33.300 so you've got this plume of anoxic soil volume, 00:17:33.300 --> 00:17:35.015 and it kills the roots. 00:17:35.015 --> 00:17:36.390 AUDIENCE: So in fact, right here, 00:17:36.390 --> 00:17:39.000 isn't it the case that there could have been an older tree 00:17:39.000 --> 00:17:40.950 the same age as these tall ones that 00:17:40.950 --> 00:17:43.140 died and was replaced by this. 00:17:43.140 --> 00:17:47.190 And possibly it died because of methane leak. 00:17:47.190 --> 00:17:49.401 PROFESSOR: Yeah, I mean, it would 00:17:49.401 --> 00:17:51.900 be very interesting to find out what the history of this is, 00:17:51.900 --> 00:17:53.316 because this is I don't know, this 00:17:53.316 --> 00:17:55.680 is maybe two to three years old is 00:17:55.680 --> 00:18:01.090 my guess from the sampling from whatever it was planted. 00:18:01.090 --> 00:18:04.920 So OK, I'm not getting anything at the very surface here, 00:18:04.920 --> 00:18:09.140 but we definitely got some there. 00:18:09.140 --> 00:18:11.850 And that's two too close to this tree, because I mean, 00:18:11.850 --> 00:18:15.160 the root system is certainly going over there. 00:18:15.160 --> 00:18:17.160 Another really interesting thing, so it actually 00:18:17.160 --> 00:18:18.480 does come back to being-- 00:18:18.480 --> 00:18:22.651 so I'm a tree physiologist actually. 00:18:22.651 --> 00:18:24.150 That's what I'm suppose to be doing, 00:18:24.150 --> 00:18:25.524 that's why I got into this stuff. 00:18:25.524 --> 00:18:28.620 But it's interesting, because some trees have 00:18:28.620 --> 00:18:32.040 a vasculature that is called segmented, 00:18:32.040 --> 00:18:36.840 and some tree species have an integrated vascular structure. 00:18:36.840 --> 00:18:41.310 What that means is that some species, the roots on this side 00:18:41.310 --> 00:18:44.670 are connected to the pipes that run water on this side 00:18:44.670 --> 00:18:47.710 and are connected to the branches on the side. 00:18:47.710 --> 00:18:52.000 And then this side operates kind of like as a parallel path. 00:18:52.000 --> 00:18:54.450 Whereas other trees species like pine, 00:18:54.450 --> 00:18:59.330 a lot of the pine species, it's like whatever comes out of here 00:18:59.330 --> 00:19:02.130 or goes through here could have been from anywhere in the soil, 00:19:02.130 --> 00:19:05.290 it's integrated, OK, spatially integrated. 00:19:05.290 --> 00:19:09.960 So if the gas leak has some spatial pattern to it, 00:19:09.960 --> 00:19:13.020 you could see differences in where it shows up on the tree 00:19:13.020 --> 00:19:16.680 depending on the tree species and its vascular structure. 00:19:16.680 --> 00:19:18.470 Look at this, look how it's breaking off, 00:19:18.470 --> 00:19:20.900 like the twigs are just snapping. 00:19:20.900 --> 00:19:23.500 This tree is not in good, it's dried out. 00:19:23.500 --> 00:19:27.300 And so this is not, this tree is having problems. 00:19:27.300 --> 00:19:29.370 You can just, I mean, I'm not killing this tree, 00:19:29.370 --> 00:19:32.280 it's just like these tips are dead. 00:19:32.280 --> 00:19:35.390 They're not hydrated. 00:19:35.390 --> 00:19:37.800 AUDIENCE: Well, this one's OK. 00:19:37.800 --> 00:19:38.300 OK, 00:19:38.300 --> 00:19:41.900 PROFESSOR: Yeah, so these are OK over here. 00:19:41.900 --> 00:19:43.740 This side is not doing so good. 00:19:43.740 --> 00:19:44.480 So I don't know. 00:19:44.480 --> 00:19:46.438 AUDIENCE: So it's something that you envisioned 00:19:46.438 --> 00:19:52.652 citizen scientist doing like measuring for methane 00:19:52.652 --> 00:19:55.510 and trace the problem for their trees, 00:19:55.510 --> 00:19:58.210 and then reporting it to the city or reporting it-- 00:19:58.210 --> 00:20:00.370 PROFESSOR: Totally, yeah. 00:20:00.370 --> 00:20:04.040 And that's the whole idea behind making this available through 00:20:04.040 --> 00:20:07.000 heat by the Sierra Club, I'm on the executive committee 00:20:07.000 --> 00:20:12.020 of the Sierra Club, so I'm like promoting the Sierra Club. 00:20:12.020 --> 00:20:15.620 But they're making these things available for communities 00:20:15.620 --> 00:20:17.990 to do what we're doing, to use your nose, 00:20:17.990 --> 00:20:22.327 to use your eyes to find. 00:20:22.327 --> 00:20:24.410 People will walk by it's like, oh, I smell a leak, 00:20:24.410 --> 00:20:27.080 and then you can go and check this out and actually 00:20:27.080 --> 00:20:30.230 find out where it is, and then report it. 00:20:30.230 --> 00:20:33.320 You don't have to wait to report it if you smell a leak, 00:20:33.320 --> 00:20:35.220 you can and should report it. 00:20:35.220 --> 00:20:37.940 But it empowers you to find out more. 00:20:37.940 --> 00:20:44.630 And Mothers Out Front has been amazing in terms of also-- 00:20:44.630 --> 00:20:46.880 it's not just what they know, but when 00:20:46.880 --> 00:20:48.350 they plant that flag in the ground, 00:20:48.350 --> 00:20:51.380 it's showing everyone else that there's a leak here as well. 00:20:51.380 --> 00:20:54.140 So just essentially making the problem 00:20:54.140 --> 00:20:57.304 transparent to everyone. 00:20:57.304 --> 00:20:58.280 AUDIENCE: [INAUDIBLE]? 00:20:58.280 --> 00:21:02.030 PROFESSOR: So Mothers Out Front has had and maybe 00:21:02.030 --> 00:21:05.055 still do a campaign where there's a leak, 00:21:05.055 --> 00:21:06.725 they just plant a yellow flag, and it 00:21:06.725 --> 00:21:09.800 has a sniffing nose on it and it basically makes it clear 00:21:09.800 --> 00:21:11.090 that there's a leak there. 00:21:11.090 --> 00:21:14.150 AUDIENCE: We did in a concentrated time period, 00:21:14.150 --> 00:21:17.820 and then we collected the flags back again. 00:21:17.820 --> 00:21:22.490 But during that process, a lot of people talked with us 00:21:22.490 --> 00:21:26.330 and were reading the information that we left 00:21:26.330 --> 00:21:28.532 attached to the flag-- 00:21:28.532 --> 00:21:29.990 AUDIENCE: Did the utility companies 00:21:29.990 --> 00:21:32.420 respond to those flags at all per se? 00:21:32.420 --> 00:21:35.810 AUDIENCE: Not in any way that we know. 00:21:35.810 --> 00:21:37.830 Audrey might know a little bit more. 00:21:37.830 --> 00:21:41.670 We didn't do any measurements, we were just 00:21:41.670 --> 00:21:44.860 going from the mapping that had been done, 00:21:44.860 --> 00:21:50.046 and we were given points where there was more 00:21:50.046 --> 00:21:52.602 significant leakage going on. 00:21:52.602 --> 00:21:54.060 PROFESSOR: And so that was actually 00:21:54.060 --> 00:21:57.090 driven by information provided by the utilities. 00:21:57.090 --> 00:22:01.761 But like a follow on development of this could be-- 00:22:01.761 --> 00:22:05.790 'cause we know that the leak map provided by the utilities, as 00:22:05.790 --> 00:22:08.430 good as Audrey did to put them faithfully 00:22:08.430 --> 00:22:10.200 down where they were looking. 00:22:10.200 --> 00:22:12.510 The utilities get it wrong sometimes, 00:22:12.510 --> 00:22:14.140 or these missing leaks-- 00:22:14.140 --> 00:22:15.315 what are we calling them? 00:22:15.315 --> 00:22:16.565 AUDIENCE: Yeah, missing leaks. 00:22:16.565 --> 00:22:19.290 PROFESSOR: Missing leaks that have come off the books. 00:22:19.290 --> 00:22:23.280 And it doesn't seem like they like 15% of them 00:22:23.280 --> 00:22:27.840 came off like on December 31st, it doesn't make sense. 00:22:27.840 --> 00:22:31.000 So it's kind of auditing them as well. 00:22:31.000 --> 00:22:33.654 And this is just us being parked here, OK? 00:22:33.654 --> 00:22:35.820 So you can see it going up and down and up and down, 00:22:35.820 --> 00:22:40.140 and that again, is just the wind wafting this leak around. 00:22:40.140 --> 00:22:42.870 So it gives you an idea of the vagaries of the weather 00:22:42.870 --> 00:22:43.660 conditions. 00:22:43.660 --> 00:22:48.180 But you can see also that even when it goes down, I mean, 00:22:48.180 --> 00:22:50.910 the lowest it ever went here is like, I don't know, 00:22:50.910 --> 00:22:53.340 2.7 or maybe 3 or so. 00:22:53.340 --> 00:22:56.160 So it's obviously a leak. 00:22:56.160 --> 00:23:00.130 But depending on the conditions, I mean, we were up above 16, we 00:23:00.130 --> 00:23:02.460 we're down to like 3. 00:23:02.460 --> 00:23:04.840 And so if you drive a leak two different times, 00:23:04.840 --> 00:23:07.336 you're going to get two different peak readings. 00:23:07.336 --> 00:23:08.794 That's part of the thing that makes 00:23:08.794 --> 00:23:14.510 it difficult to estimate like really how big the leak is. 00:23:14.510 --> 00:23:17.430 This is still the Swiss Alps of leaks. 00:23:17.430 --> 00:23:18.610 OK, here's the school. 00:23:22.602 --> 00:23:24.600 AUDIENCE: What are you at? 00:23:24.600 --> 00:23:27.233 PROFESSOR: 2.4, 3.3, OK, so there's a leak right here 00:23:27.233 --> 00:23:29.510 at the school, 2.37. 00:23:29.510 --> 00:23:31.100 So when you see it dip down like that 00:23:31.100 --> 00:23:33.308 and then come back up like that, that's pretty clear. 00:23:33.308 --> 00:23:37.010 We're moving at a steady pace here, so got a leak here. 00:23:37.010 --> 00:23:38.700 I didn't pay attention to the trees. 00:23:38.700 --> 00:23:39.600 AUDIENCE: 4. 00:23:39.600 --> 00:23:41.350 PROFESSOR: 4, OK. 00:23:41.350 --> 00:23:45.920 Some young trees, patches. 00:23:45.920 --> 00:23:50.260 AUDIENCE: 3.8, 3.4, 2.9. 00:23:50.260 --> 00:23:52.325 PROFESSOR: OK, that tree [INAUDIBLE].. 00:23:56.080 --> 00:23:57.670 All right, so leaks there. 00:23:57.670 --> 00:23:59.104 9. 00:23:59.104 --> 00:23:59.997 We got 9. 00:23:59.997 --> 00:24:00.538 AUDIENCE: 12. 00:24:00.538 --> 00:24:01.494 PROFESSOR: 11. 00:24:01.494 --> 00:24:03.265 AUDIENCE: 11. 00:24:03.265 --> 00:24:04.640 PROFESSOR: You want to pull over? 00:24:04.640 --> 00:24:05.265 AUDIENCE: Yeah. 00:24:05.265 --> 00:24:06.428 PROFESSOR: OK. 00:24:06.428 --> 00:24:08.660 AUDIENCE: And you see the yellow markings everywhere, 00:24:08.660 --> 00:24:11.200 and that's always gas, the yellow is gas. 00:24:11.200 --> 00:24:15.370 PROFESSOR: Yeah, yellow always refers to gas. 00:24:15.370 --> 00:24:18.280 Blue is water. 00:24:18.280 --> 00:24:21.900 PROFESSOR: So it's like you see stuff every time that's 00:24:21.900 --> 00:24:22.900 just a little different. 00:24:22.900 --> 00:24:26.090 Like I don't know if I've ever seen a marking like right 00:24:26.090 --> 00:24:30.560 on a curbstone like that for [INAUDIBLE].. 00:24:30.560 --> 00:24:33.609 I guess that's the arrow [INAUDIBLE].. 00:24:33.609 --> 00:24:35.650 PROFESSOR: Yeah, but there seems to one here too, 00:24:35.650 --> 00:24:39.246 so are there two 12 inch mains running down the street 00:24:39.246 --> 00:24:40.440 that way underneath us. 00:24:40.440 --> 00:24:42.460 PROFESSOR: You have multiple mains. 00:24:42.460 --> 00:24:45.380 Oh, I think of bracketing it here. 00:24:45.380 --> 00:24:47.250 So you can see the two yellow lines. 00:24:47.250 --> 00:24:50.360 But here it is, 12 inch cast iron. 00:24:50.360 --> 00:24:52.800 Cast iron is the old leaky stuff. 00:24:52.800 --> 00:24:58.000 It's the most leak prone, most prevalent leak prone pipe. 00:24:58.000 --> 00:24:59.714 PROFESSOR: So with cast iron, they 00:24:59.714 --> 00:25:01.130 way they originally did it is they 00:25:01.130 --> 00:25:04.550 put jute, which is sort of a grass, between the two joint-- 00:25:04.550 --> 00:25:05.840 to close the joints. 00:25:05.840 --> 00:25:10.020 And then as gas got less humid, because they 00:25:10.020 --> 00:25:14.410 decreased the humidity of the gas, that jute dried out. 00:25:14.410 --> 00:25:18.160 And so they're basically almost all cast iron 00:25:18.160 --> 00:25:22.810 has problems, every 12 feet, because of that. 00:25:22.810 --> 00:25:23.914 AUDIENCE: Wow. 00:25:23.914 --> 00:25:26.736 PROFESSOR: Let's see if we get anything out of here. 00:25:26.736 --> 00:25:29.157 PROFESSOR: Nathan and Bob Ackley went out to-- 00:25:29.157 --> 00:25:30.990 PROFESSOR: All that work and we got nothing. 00:25:33.750 --> 00:25:35.410 So it's not [INAUDIBLE]. 00:25:39.455 --> 00:25:44.534 Now these are drill holes, so kind of push it there 00:25:44.534 --> 00:25:45.700 and see if you get anything. 00:25:45.700 --> 00:25:49.440 Just hold it down, you'll hear it slow down, 00:25:49.440 --> 00:25:54.240 the pump slow down if you push it too hard. 00:25:54.240 --> 00:25:55.440 OK, nothing there. 00:25:55.440 --> 00:25:58.649 So drill holes are for the gas company when they come out. 00:26:12.230 --> 00:26:15.300 OK, let's come out quick and try these. 00:26:15.300 --> 00:26:18.630 All right, so let's go out here and let's just test-- 00:26:18.630 --> 00:26:22.460 let's stick it in one of these things real quick. 00:26:22.460 --> 00:26:25.460 Leave it in for about 10 seconds. 00:26:25.460 --> 00:26:28.740 And maybe someone can make sure we don't get hit. 00:26:28.740 --> 00:26:30.730 Keep an eye out. 00:26:30.730 --> 00:26:33.350 AUDIENCE: OK, there we go. 00:26:33.350 --> 00:26:39.774 40.4. 00:26:39.774 --> 00:26:40.940 PROFESSOR: Keep it in there. 00:26:40.940 --> 00:26:43.644 Keep it in there. 00:26:43.644 --> 00:26:44.560 AUDIENCE: Cars coming. 00:26:44.560 --> 00:26:46.060 PROFESSOR: All right, we can get up. 00:26:46.060 --> 00:26:48.890 OK, so definitely gas in there. 00:26:48.890 --> 00:26:54.620 OK, so yeah, we didn't really find-- 00:26:54.620 --> 00:26:58.385 we found the leak, but we didn't find any large concentration. 00:26:58.385 --> 00:27:00.260 AUDIENCE: It might have been a little further 00:27:00.260 --> 00:27:02.090 down the block, the scent. 00:27:02.090 --> 00:27:05.090 PROFESSOR: I mean, it's all along this block, so yeah. 00:27:05.090 --> 00:27:07.190 This is relatively new, right, look at the line 00:27:07.190 --> 00:27:10.170 where the new paving was. 00:27:10.170 --> 00:27:13.140 This intersection was redone with a new everything, 00:27:13.140 --> 00:27:13.830 we got gas. 00:27:13.830 --> 00:27:20.330 So this is an example of a lost opportunity. 00:27:20.330 --> 00:27:24.610 PROFESSOR: With MAPC, he did a study to sort of figure 00:27:24.610 --> 00:27:28.840 out how much municipalities and gas companies could 00:27:28.840 --> 00:27:31.540 save by doing sort of more integrated infrastructure 00:27:31.540 --> 00:27:33.170 repair and not screwing up like this. 00:27:33.170 --> 00:27:34.640 AUDIENCE: Here comes a, yep. 00:27:34.640 --> 00:27:38.620 PROFESSOR: And it was like $1 billion. 00:27:38.620 --> 00:27:42.910 You can check it out and fixourpipes.org. 00:27:42.910 --> 00:27:45.480 It's a really beautiful website. 00:27:45.480 --> 00:27:48.930 PROFESSOR: So it was just a little bit. 00:27:48.930 --> 00:27:54.729 But there is gas, I mean, so that's not good. 00:27:54.729 --> 00:27:56.270 PROFESSOR: So you can sort of imagine 00:27:56.270 --> 00:27:58.490 like all the infrastructure underneath, both the gas 00:27:58.490 --> 00:28:00.830 pipes and the electric and the water mains and stuff 00:28:00.830 --> 00:28:03.150 like that, as well as the paving. 00:28:03.150 --> 00:28:05.930 And the paving alone in Massachusetts 00:28:05.930 --> 00:28:10.280 I think is $600,000 on average per mile. 00:28:10.280 --> 00:28:13.720 So it's just expense layered on expense on expense. 00:28:13.720 --> 00:28:17.160 And so if you fix anything, if you cut into the pavement 00:28:17.160 --> 00:28:20.864 for any reason, you should just fix all of it at the same time. 00:28:20.864 --> 00:28:22.780 'Cause otherwise, it's like operating 00:28:22.780 --> 00:28:25.330 on somebody's appendix and finding a broken artery, 00:28:25.330 --> 00:28:27.900 and be like, oh, whatever. 00:28:27.900 --> 00:28:30.790 Forget that, we'll take care of that some other time. 00:28:30.790 --> 00:28:32.640 Not our responsibility.