Why Shortcutting a Standard Doesn’t Work

January 28, 2016

As you know I try to stay abreast of the goings on in our industry. Like when a competitor launches a new product or a testing lab introduces a new standard. I am particularly interested if these events are in any way linked. 

Last year I was aware of a manufacturer that launched a new HGI series designed to compete in the high-efficiency/high-capacity market.  The series offered two units, one certified at 75 gpm and one at 100 gpm.

As a self-proclaimed watchdog I like to review new products to make sure that the claims made by a manufacturer about the performance of their units can actually be verified by a third party.

Since this manufacturer went with NSF International as their third party testing and certification lab, it’s easy to verify the manufacturers’ claims because NSF posts certifications online at their NSF Product and Services Listing site.

What is noteworthy about this particular manufacturer’s listing is that it shows certifications to ASME A112.14.3, CSA B481 and a standard you may not have seen before, SE 15741.

What is SE 15741? 

It is an NSF Special Engineered Specification.  This one is titled, “Testing of Large Capacity Grease Interceptors Using an Accelerated Protocol.”

What is the purpose of this specification?

According to the document, “The purpose of this Special Engineered document is to evaluate the capacity of grease interceptors above the minimum capacity requirements found in ASME A112.14.3 using an accelerated test protocol.”

The accelerated protocol consists of two phases. In phase one, the unit is tested up to its breakdown point or a maximum of 15 increments whichever is less.  That means that if the unit has not reached its breakdown point by the 15th increment then phase one is to be stopped. In phase two, the increments are accelerated by adding lard “directly through the lid in quantities specified by the manufacturer” between increments followed by a regular incremental test.  This is to be done until breakdown or a maximum of another 15 increments.

Please understand that ASME A112.14.3 does not allow an accelerated protocol for testing grease interceptors. The standard requires an interceptor to be tested incrementally until the unit reaches its maximum grease retention capacity, which is established at the increment preceding two successive increments in which either the average efficiency is less than 90 percent or the incremental efficiency is less than 80 percent.  The standard does not allow any lard to be introduced directly into the interceptor through the lid nor does it allow for fixing any set number of increments in determining the units’ efficiency and capacity.

Stop and consider what the implications of this accelerated protocol are.

First, every drop of lard that is introduced into the grease interceptor through the lid is added at 100 percent efficiency.  This automatically skews the efficiency results rendering them invalid for certification purposes. 

Second, the accelerated protocol sets arbitrary limits on the number of test increments at 15 for both phases. Since the ASME standard requires two successive increments in which either the average efficiency is less than 90 percent or the incremental efficiency is less than 80 percent, stopping the test at the 15th increment during either phase, potentially eliminates the possibility of having two successive increments to base the final results on.

Finally, since the manufacturer gets to decide how much grease to add to the interceptor directly through the lid, the amounts can change or vary depending on how the test results are being reported allowing the manufacturer to manipulate the test to get more favorable results.

The accelerated protocol established in NSF SE 15741 is not an acceptable modification of the ASME A112.14.3 standard and it should not be relied upon for accurately reporting the efficiency and capacity of a HGI. 

Furthermore, SE 15741 is not an approved standard in the UPC, IPC, NSPC, NPCC, nor any state or local plumbing codes. 

We always recommend that you ask to see a manufacturer’s actual test report, including the incremental test results so that you can verify the claims of performance the manufacturer makes.  And, if you see something you don’t understand or that doesn’t make sense, hold the manufacturer and the testing lab accountable. 


  • Wayne Harrison

    Jan 28, 2016

    This is not a recognized standard, it is just a procedure to make money on testing. This is not recognized by ASME A112.14.3, nor anyone else. . SE 15741 (Special Engineering year 2015 number 741)
    I sit on that board and this is NOT approved by ASME A112.14.3 nor anyone else.

  • Max Weiss

    Jan 28, 2016

    Yes, I agree, essentially, with both comments. The self acclaimed “accelerated protocol” is not an accelerated iteration of any referenced testing standard.

    There are two basic testing formats expressed in code referenced standards: PDI G-101; ASME A112.14.3; B 481. First, testing to rated capacity – that minimum quantity of lard retention necessary for certification; second, testing to breakdown – that quantity of lard retention at the test increment number two increments preceding that increment in which average retention is below 90 percent or an increment is below 80 percent.

    The reason pre-loading an interceptor is not a scientifically valid procedure is because doing so ignores the effect of flow distribution deposition within the interceptor. Each test increment, transporting approx. 11,380 mg/L lard has an effect on successive increments’ flow
    characteristics. The hallmark elements of scientific validity – repeatability and accuracy notwithstanding, the procedure in SE 15741 is not a sound basis for measuring expected performance of an interceptor containing a given quantity of grease.

    Stopping the test at 15 increments in the “required retention for certification” test is done because that is the minimum number of increments necessary to attain the required retention. Segments of 15 increments beyond manually depositing lard in the interceptor has no relevance to any recognized standard. It is an arbitrary procedure.

    A valid measure of the performance of larger capacity interceptors is to test to breakdown according to the protocol in one of the recognized testing standards. SE 15741 is an effort to cut costs; the price is validity.

  • Robert Heavey

    Jan 28, 2016

    In reading this article, I first had the impression that this manufacturer is doing something ‘shady’, and their interceptor is somehow deficient for use under the UPC or IPC. But, further review notes that they ARE certified to ASME A112.14.3, which makes them completely acceptable. I agree that the SE 15741 is a lower standard than ASME A112.14.3, and as you have described it, makes little sense. But the inclusion of this lesser, ‘me too’ standard does not affect the certification under ASME A112.14.3. In fact, this manufacturer could also add that it has been tested to and meets the requirements of many other standards (including ‘lead free’ certification!), without affecting its ASME A112.14.3 status.
    I completely agree with your take on the SE 15741 ‘accelerated’ standard – it’s hard to believe that anyone would see value in dumping lard directly into the interceptor lid. Now we need to make sure that this standard is never adopted by the model codes!

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