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Thread: Backflow test kit calibration

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    DIY Junior Member csFF's Avatar
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    Default Backflow test kit calibration

    Does anyone know how to calibrate their test kits themselves? Wanting to know if I could build a station to test them and not have to send them off somewhere and spend the money to have them tested. Anyone ever done this or know how to do this? Thanks...

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    In the Trades Gary Swart's Avatar
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    I have seen the one my inspector uses, it doesn't appear to be overly high tech. I have no idea where you buy them or what the requirements are to become certified, but at least in my area there are a fair number of inspectors on the list I receive each spring that I may contact so I'd have to believe that it doesn't require an MA in water management.

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    Moderator & Master Plumber hj's Avatar
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    I would think the calibration would have to be "certified" to ensure that the device is testing properly.
    Licensed residential and commercial plumber

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    DIY Junior Member csFF's Avatar
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    I would think one would be able to construct a water column or 2, with specific markings for 1 psi at the bottom (27.68 inches at top mark) and hook up the backflow tester to it and then dial it in where it is supposed to be. I'm just wondering if anyone has ever constructed such a calibrator.

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    DIY Senior Member guy48065's Avatar
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    I'm sure such "calibration" rigs are cobbled together frequently by DIY'ers and amateurs but a pro needs his tools to read right and to be verified against real standards. Any calibration has to be traceable to primary standards but the buck stops dead at a home-made "standard". A pro can get in deep legal doo-doo by relying on uncalibrated or home-made instruments.
    Romeo and Atlanta, MI

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    Moderator & Master Plumber hj's Avatar
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    Theoretically, you could "calibrate" it to any "standard" you wanted to so that all your tests would either pass the test, or fail so you would have to repair them.
    Licensed residential and commercial plumber

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    In the Trades Gary Swart's Avatar
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    I'm by no means an expert, but if EPA rules are followed, back flow devices must be inspected and certified by a licensed inspector periodically. As I stated in my first answer to your question, the instruments do not appear to be overly high tech, but they do have to meet industry standards. I do not think a homemade device as you describe would qualify. Why do you want to reinvent the wheel anyway, these instruments are already manufactured and will meet the requirements. You do have to be trained, licensed, and certified to make the inspections valid.

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    DIY Junior Member csFF's Avatar
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    I am a licensed backflow tester by the ASSE and have been since 2000. I need to get several backflow test kits recalibrated, as I'm pretty sure they are supposed to be every year. I guess I don't know of a requirement that they be recalibrated at an independent facility, or if I could simply recalibrate them myself. I'm really not even asking what the standard is so much as I am asking if anyone has ever tried to or seen somebody build a calibration station using water column(s) to recalibrate their backflow tester. I guess I'm just kind of curious if it can be done in the workshop rather than send it away and wait for it to come back for a couple of weeks and spend $100+ plus per instrument each time, thats all. And no, I would never 'calibrate' it to any different 'standard' than what is proper, simply to sell backflow rebuilds. I hate rebuilding backflow preventers, they're a pain in the a$$ usually, and customers ABHOR it when you tell them their BF failed (probably because many testers 'pass' them regardeless of test results. I would much rather the device simply pass, I collect the measly amount of money we charge them, and I be on my way to more profitable ventures.

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    Geologist sjsmithjr's Avatar
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    What you are proposing is not feasible for many reasons, the biggest one being that the equipment used to perform an accuracy check has to be much more accurate that device being tested. Read Southern California’s Manual of Cross-Connection Control and the American Water Works Association (AWWA) Recommended Practice for Backflow Prevention and Cross-Connection Control (Manual M14). These are the "go to" documents used by most state and local governments to develop their requirements for verifying the accuracy of backflow device test equipment. Field test equipment must be accurate to with +/- 0.2 PSID as measured at 1,2,5,7, and 14 PSID. The gauge used to verify the accuracy of the field test equipment must have "a calibration traceable to the National Institute of Standards and Technology (NIST). The verification reference source should have a maximum permissible error of ± 0.05 pound-force per square inch gauge (psig)."
    Last edited by sjsmithjr; 12-04-2013 at 03:05 PM.

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    DIY Senior Member guy48065's Avatar
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    My point earlier in doing it "right" vs. DIY is consider the Worst Case Scenario: Your customer gets gravely ill and the hospital determines it's from contaminated water. You could end up a defendant on the witness stand and if your "calibration" wasn't traceable it wouldn't matter if your gauges ARE more accurate than national standards--the lawyers will eat you alive. Don't risk it.
    Romeo and Atlanta, MI

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    Moderator & Master Plumber hj's Avatar
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    quote; Your customer gets gravely ill and the hospital determines it's from contaminated water.

    First they would have to prove WHERE the contaminated water came from, since it could NOT be from the hospital itself, because the BFP is to prevent YOUR water from entering the system and flowing somewhere else, such as that hospital. NOT being able to trace it is the reason why they require that all units be tested by a certified technician with reliable equipment.
    Licensed residential and commercial plumber

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    In the Trades Tom Sawyer's Avatar
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    Back flow testing equipment has to be certified by a 3rd party certification or sent back to the manufacturer for calibration.
    Not following the proper procedure puts you in serious liability
    [B]No, plumbing ain't rocket science. Unlike rocket science, plumbing requires a license[B]

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    Geologist sjsmithjr's Avatar
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    Quote Originally Posted by Tom Sawyer View Post
    Back flow testing equipment has to be certified by a 3rd party certification or sent back to the manufacturer for calibration.
    Not following the proper procedure puts you in serious liability
    Regarding liability - requirements vary greatly from state to state and even between municipalities within the same state. Some states, such as Missouri I believe, have no regulatory requirement for third party accuracy testing of the gauges used in the testing of backflow prevention assemblies traceable to NIST. Some states and municipalites do. Some states require calibration but do not specify frequency and do not require third pary certification or the procedures to be followed.
    -Sam Smith
    Licensed Professional Geologist - AL, TN, KY

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    DIY Junior Member csFF's Avatar
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    Quote Originally Posted by sjsmithjr View Post
    Regarding liability - requirements vary greatly from state to state and even between municipalities within the same state. Some states, such as Missouri I believe, have no regulatory requirement for third party accuracy testing of the gauges used in the testing of backflow prevention assemblies traceable to NIST. Some states and municipalites do. Some states require calibration but do not specify frequency and do not require third pary certification or the procedures to be followed.
    And I am in Missouri. I think this thread has taken an understandable turn down another path. All I was wondering is if anyone knew how, or has done themselves, built a device to calibrate their own BF test kits. I'm not really asking about whether or not someone SHOULD calibrate their own test kits, and the ramifications thereof.

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    In the Trades Tom Sawyer's Avatar
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    It is possible to build something but whats the point? If you can't rely on the accuracy of the equipment then the equipment itself is pretty much useless. I'll give you an example.
    A lot of plumbers go out on a service call for a leaking backflow preventer or an RPZ. So they get there, tear the unit down and install new baskets and gaskets, turn the water on, it doesn't leak so they call it good without testing the unit. So how do they know if the BFP was bad or just doing its job? When you test a BFP you are supposed to be a certified tester using certified test equipment otherwise there is no point in certifying either. There is liablilty involved here that comes directly back on to you. If for some reason a BFP that you tested and passed, allows contaminated water to enter the potable system and if someone gets sick or dies the lawyers are going to find out if the last person who tested the device was certified to do so and if his equipment was certified and up to date. But, actually building your own manometer or using a manometer to check your stuff can be done, just shouldn't be relied on.
    [B]No, plumbing ain't rocket science. Unlike rocket science, plumbing requires a license[B]

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