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Opinions on Con Ed's New Gas Leak Detectors

D107
D107 Member Posts: 1,798
edited August 2021 in Gas Heating
I found a message from ConEd today on my phone asking me to set up an appointment for them to install their new gas detector near my indoor gas meter. First I ever heard about it. Apparently they've been doing this for awhile. I wonder if techs here find it to be a reliable unit. I'm leery of any unit that automatically blares an alarm and calls the Gas Co. I certainly see the value, but I'd like to find out which make and model they're installing. I'm aware of how crazy some of those cheaper CO alarms drove residents and fire departments over the years.

Comments

  • Bob Harper
    Bob Harper Member Posts: 914
    Most combustible gas alarms have established 20% of the LEL as the alert level. Since the Lower Explosive Limit for Natural Gas is about 4.4% by volume or 44,000 ppm, a concentration of 8,800 ppm should trigger an alert. Note that most people can detect the odorant gas (typically a mercaptan) at about 1-2 ppm. Roughly 15% of the population seem to not be sensitive to most common odorants such as ethyl or methylmercaptan. Alone, these gases can typically be sensed in the ppb range. Dilution takes them to ppm range. Note there are about 20 common odorants used and not all are sulfur based like the mercaptans.
    The CO alarm mess in Chicago was due to poor first generation design coupled with a temperature inversion that trapped the smog. Unfortunately, the response was exactly the opposite of what it should have been. They dummied the alarms instead of improving the sensors (which finally did come with the advent of cost effective electro-chemical sensors over MOS metallic oxide sensors, which don't discriminate). That's why you should get unlisted low level CO monitors instead of listed CO alarms.
    I would be interested to hear what their alert levels are over what time period. Please keep us informed.
    D107
  • D107
    D107 Member Posts: 1,798
    edited August 2021
    @Bob Harper Thanks, will do. Re: CO Alarms, we've never used the listed models, only the NSI and now the 'Defender' low-level monitors, all of which have worked out very well. We've also heard about the CO Experts models. In the over ten years we've had them, all alerts have come from a dirty stove, usually reading up to 10ppm. Now that we make sure to keep our stove clean, no more alerts.

    Re: the gas detector, Southern Cross, Inc. installs the unit. So far the only model I've seen promoted is the New Cosmos ML-310CE--see below photos and bottom attached pdf specs. Specs say Alarm Level: 10%LEL, which based on your post would be about 4400ppm? Response time is 120 sec in their ideal test environment.

    Their PR says: "Con Edison is installing 376,000 smart-technology natural gas detectors for customers in New York City and Westchester County, providing an unprecedented level of protection against potentially dangerous leaks.
    The distribution of the detectors follows a successful pilot in which Con Edison provided 9,000 detectors. Those detectors sounded 250 alarms since the first installations in October 2018. The current version of the detector lasts six years. Due to technology improvements, those installed starting in the middle of next year will last seven years and those installed starting in 2023 will have a 10-year lifespan."


  • Sal Santamaura
    Sal Santamaura Member Posts: 381

    ...you should get unlisted low level CO monitors instead of listed CO alarms...

    I strongly disagree with this advice. Failure to install and maintain a listed CO alarm, required by most codes, is a very financially risky proposition. It opens a building owner to liability and can render insurance invalid.

    The better advice is to do what I've done. Install the stupid UL devices. Then also install low level CO monitors. Yes, regulations are a pain, but keeping oneself physically and financially safe is smart.
    D107rick in AlaskaCanucker
  • mattmia2
    mattmia2 Member Posts: 5,506
    What is that fitting that looks like two jam nuts on a nipple to the right of the meter on the service?
    D107
  • D107
    D107 Member Posts: 1,798
    @mattmia2 Don't know; that's just a ConEd PR photo, not my service.
  • rick in Alaska
    rick in Alaska Member Posts: 1,362
    To me the fitting looks like a dresser coupling, which I didn't think would be allowed, but it also has a lot of writing on it, which I wouldn't think a coupling would have. So, just a wild guess.
    Rick
    mattmia2D107
  • SlamDunk
    SlamDunk Member Posts: 1,282
    edited August 2021
    I think that is a great idea. I'm so paranoid about natural gas leaks that I have a Night Hawk in the basement and a First Alert in the attic near gas piping.

    To further sate my paranoia, once a year, I bring home a gas sniffer from work to check things out a little better. Why? Both my wife and I knew people killed in gas explosions. Both homes had leaking gas logs- ( we don't have gas logs!). The family survivors were devastated. Both were dads at work.

    Lately, as you are aware, there have been other reasons that caused gas leaks that resulted in houses and buildings to exploding. Most recently, near us in Durham NC a contractor running a fiber optic line under a sidewalk hit a gas line outside a building; the gas seeped into the basement under a coffee shop. The building came down, the coffee shop owner was killed and many were injured.

    A gas detector is cheap insurance.
    D107
  • Bob Harper
    Bob Harper Member Posts: 914
    If you have to install a CO alarm listed to UL2034 by code then there is no choice. You have to follow the law. The intent of my statement was if you have a choice, start with an unlisted low level monitor, which can protect you from low level injury whereas the UL listed junk cannot. The unlisted monitors help keep you physically protected. The listed junk does not.
    kcopp
  • dopey27177
    dopey27177 Member Posts: 872
    They work 24/7. Te nose works only when you are in basement near the gas meter.

    Be safe have the gas detector installed.

    Life is cheap in China not here.

    Jake
    D107SlamDunk
  • D107
    D107 Member Posts: 1,798
    edited August 2021
    @dopey27177 There's no real question as to IF I will have the detector installed; I just want to find out more about the specific model they intend and see if there's a choice. Usually the fear with these kinds of things is false alarms. I should be hearing from the manufacturer soon.


  • STEAM DOCTOR
    STEAM DOCTOR Member Posts: 1,483
    mattmia2 said:
    What is that fitting that looks like two jam nuts on a nipple to the right of the meter on the service?
    Standard in lots of jurisdictions. Think it's there to mitigate affects of lighting strikes (at least that's what a gas fellow told me once, can't quite remember who).
    mattmia2
  • D107
    D107 Member Posts: 1,798
    edited August 2021
    @Bob Harper Ok I have heard from the company that manufactures the gas detector and it would appear to me that the detector will be fine to have installed. I have edited out of this thread my speculative comments. The only discrepancy I see here is that you said the most people can detect the odorant gas at 1-2ppm, whereas the company states below that 'humans, on average, can smell natural gas when an odorant is added at around 20-25% LEL. If 10%LEL represents around 5000ppm, and humans only sense it at 20-25%LEL––many more times the ppm, then this will alarm way before humans can detect it, which makes sense from a safety point of view. Did I misunderstand your 1-2ppm reference? Let me know so I can re-edit thread.
    Manufacturer Comments:
    1. In terms of response time, this would vary depending on gas leak location compared to device location, flow of gas, any obstructions near the ceiling, etc. but when QA tested in a test chamber, 120 seconds would be correct.
    Residents should not have to worry about false alarms, due in part to the filter technology implemented on the sensor. Our device has been independently tested by GTI (Gas Technology Institute) for nuisance alarms with a variety of common household products, and none of these products caused the device to alarm. In addition, prior to the mass deployment of our devices, ConEd did a field pilot of 9,000 units, in which there were no false alarms.
    10% LEL represents 5,000ppm. Humans, on average, can smell natural gas when an odorant is added at around 20-25% LEL. This does not take into account any other factions, such as odor fatigue, diminished sense of smell, or the odor being absorbed by the soil in the event of an outdoor leak migrating indoors. 25% LEL is also the alarm threshold for other gas alarms. Our lower alarm threshold provides you with additional time to react, without being too low to worry about false alarms. Regarding gas detection at 1-2ppm levels, this is more common in portable gas detectors. Fixed gas alarms will have less resolution and higher alarm setpoints due to the physics behind the sensors being used.
    2. Con Ed is currently installing 6-year devices, with the plan to begin receiving 7-year devices from us later this year. We will be offering 10-year products to ConEd starting in 2023.
    3. The 5-year lifetime of the ConEd device was for the version used during the pilot testing. They now are installing 6-year devices with their mass deployment of units. This refers to the device's longevity, specifically the sensor, regardless of the battery. The custom battery provided with the device will last the entire product lifetime without need of replacement either by you or ConEd.
    4. It is the Silver Spring smart reader connected to your electric meter that would make you a viable candidate to receive an ML-310CE model from ConEd. Because it is the electric meter that has this smart reader, rather than the gas meter, the New Cosmos ML-310CE actually communicates through the electric meter.
  • mattmia2
    mattmia2 Member Posts: 5,506
    The odorant is added to the gas at a concentration such that it is readily detectable when the gas is at a concentration of 20% of the LEL. That would mean if the odorant becomes readily detectable at 1-2 ppm, the mixture of the gas, the air, and the odorant would be at 1-2 ppm when the mixture of the air and the gas brings the concentration of the gas to 20% of the LEL.(readily detectable is probably a somewhat higher concentration than "most people can detect").
    D107
  • SlamDunk
    SlamDunk Member Posts: 1,282
    These days, a lot of people have lost their sense of smell. Another good reason for a detector.
  • Bob Harper
    Bob Harper Member Posts: 914
    I don't know what they're smoking but 99% of housewives can detect about 1-2 ppm leaks. I have explained trace gas leakage and the ANSI stds. for allowable leakage for 35 yrs to no avail. The 20% was chosen because they knew you can't get 100% leak-proof. Even spaceships and submarines leak. It's just a question of how much is a problem. The 20% provides a safety margin of 5:1. Most safety designs use 4:1 so this is a little more conservative.

    I can assure you a gas sniffer than can't sense below 20% of the LEL is a paperweight or doorstop. Plenty of units on the market that can detect 50ppm or less. The sniffer is also important with LP gas because your nose would have to be near the floor to get a Whiff of Jiff. I knew a construction super who blew up and died because the gas leak was below his nose when he lit the WH pilot. The LEL of NG is 4.4% depending upon the analysis or purity of the gas/ LPG runs about 2.15%. That's 44,000/21,500 ppm. Therefore, 20% is 8,800/4,300 ppm.

    According to the National Propane Gas Assn, one pound of ethyl mercaptan is added to 10,000 gallons of propane. They state the odor threshold is one part per billion. NFPA 54 and 58 require an odor threshold of 20% LEL. That's the requirement- not the actual level found in the field. If you don't believe me, get their supersniffer, warm it up so it's ticking about once per second in clean air. Crack open a gas pipe, sit next to it, and have someone walk towards you with the sniffer in one hand and a burning candle in the other. Report back how far away you stop him or can he reach you before the sniffer alerts that you're 20% of the way towards going Poof!. Don't worry, the gas cannot possibly ignite below the LEL (theoretically). Of course, the gas is not uniform as there are pockets of high concentration often right next to barely detectible levels.

    From Gasodorizerdotcom: Q. WHAT MAKES IT IS A GOOD IDEA TO INJECT IT INTO NATURAL GAS?
    A. The simple answer is that mercaptan is not harmful at the levels used when odorizing natural gas. The nose can detect mercaptan at a 1.6 PPB (parts per billion), and the typical range of odorants in natural gas ranges from 0-10 ppm (parts per million). Additionally, the Occupational Safety and Health Administration (OSHA) has set the permissible exposure limit for the mercaptan at 10 PPM of air.

    HTH,
    D107
  • SlamDunk
    SlamDunk Member Posts: 1,282

    I don't know what they're smoking but 99% of housewives can detect about 1-2 ppm leaks.

    I was alluding to people with covid who have lost their sense of smell recently. But you don't have to have covid. I can't smell natural gas when many people can. I need a very large leak before I can smell it. My sister completely lost her sense of smell five years ago. And then there are homeowners-like my wife, who refuse to go into the basement or attic. So, in many cases, a detector is better than a nose.

  • ChrisJ
    ChrisJ Member Posts: 12,819
    edited August 2021

    I don't know what they're smoking but 99% of housewives can detect about 1-2 ppm leaks. I have explained trace gas leakage and the ANSI stds. for allowable leakage for 35 yrs to no avail. The 20% was chosen because they knew you can't get 100% leak-proof. Even spaceships and submarines leak. It's just a question of how much is a problem. The 20% provides a safety margin of 5:1. Most safety designs use 4:1 so this is a little more conservative.

    I can assure you a gas sniffer than can't sense below 20% of the LEL is a paperweight or doorstop. Plenty of units on the market that can detect 50ppm or less. The sniffer is also important with LP gas because your nose would have to be near the floor to get a Whiff of Jiff. I knew a construction super who blew up and died because the gas leak was below his nose when he lit the WH pilot. The LEL of NG is 4.4% depending upon the analysis or purity of the gas/ LPG runs about 2.15%. That's 44,000/21,500 ppm. Therefore, 20% is 8,800/4,300 ppm.

    According to the National Propane Gas Assn, one pound of ethyl mercaptan is added to 10,000 gallons of propane. They state the odor threshold is one part per billion. NFPA 54 and 58 require an odor threshold of 20% LEL. That's the requirement- not the actual level found in the field. If you don't believe me, get their supersniffer, warm it up so it's ticking about once per second in clean air. Crack open a gas pipe, sit next to it, and have someone walk towards you with the sniffer in one hand and a burning candle in the other. Report back how far away you stop him or can he reach you before the sniffer alerts that you're 20% of the way towards going Poof!. Don't worry, the gas cannot possibly ignite below the LEL (theoretically). Of course, the gas is not uniform as there are pockets of high concentration often right next to barely detectible levels.

    From Gasodorizerdotcom: Q. WHAT MAKES IT IS A GOOD IDEA TO INJECT IT INTO NATURAL GAS?
    A. The simple answer is that mercaptan is not harmful at the levels used when odorizing natural gas. The nose can detect mercaptan at a 1.6 PPB (parts per billion), and the typical range of odorants in natural gas ranges from 0-10 ppm (parts per million). Additionally, the Occupational Safety and Health Administration (OSHA) has set the permissible exposure limit for the mercaptan at 10 PPM of air.

    HTH,


    All of the gas piping I've done doesn't appear to leak even during pressure tests for months at a time on some sections.

    And I have refrigerators that aren't low on charge after 88 years, two of which use a gas that can be tasted as low as 0.35 ppm and smelled with the nose at 0.67 ppm.

    Not sure about submarines and spaceships, those are kind of out of my wheelhouse.


    I get that very small leaks are harmless, and likely common. I just disagree that you can't get leakproof.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • D107
    D107 Member Posts: 1,798
    edited August 2021
    @Bob Harper @mattmia2 The only way I can figure out the discrepancy between 1-2pm sniffability and 8800ppm (20% LEL) sniffability is that the company is being extra conservative and including situations where the gas detector is behind a basement sheetrock wall and access door or other obstruction where the gas will not flow freely into the room occupied by the resident and may in fact dissipate upwards along the house walls. But that's still a huge number of ppm to account for.

  • D107
    D107 Member Posts: 1,798
    edited August 2021
    @Bob Harper @mattmia2 I have heard back from the manufacturer, who writes, fwiw:
    "After reading into this further, I am wondering if the discrepancy arises from confusion between the concentration of mercaptan and the concentration of natural gas. As you stated, it seems mercaptan can be detected as low as 1ppb, and that most odorants are added at concentrations between 0-10ppm. I think the first statement regarding housewives being able to smell gas at concentrations of 1-2ppm is referring to, whether intentionally or not, the mercaptan concentration, not the gas concentration. In this regard, a natural gas leak at 20%LEL (10,000ppm for methane) could very likely have a concentration of mercaptan at 1-2ppm, at which point it would be detectable by the human nose.

    In addition, here is the information Con Edison provides on their website regarding odor fade:

    Odor Fade
    Certain conditions or circumstances may diminish the smell of mercaptan. If you have a weak sense of smell, odor fatigue from smelling the same aromas for an extended period, or if multiple competing odors are in the area, you may not be able to detect the odorant.

    Physical or chemical processes may cause the odorant to fade to the point where it’s no longer detectable, including:
    Adsorption, absorption, and oxidation.
    Newly-installed metal, or sometimes plastic, piping (utility or customer).
    Size, length, and configuration of the piping.
    The presence of rust, moisture, or other substances in the pipe.
    Gas composition, pressure, and/or flow. Intermittent, little, or no flow over an extended period of time may result in the loss of odorant until gas flow increases or becomes more frequent.
    If a natural gas leak occurs underground, the surrounding soil may cause odor fade such that the odorant may not be detected by smell in the atmosphere."

    mattmia2