Ultrasonic Transit Time flow meter for fire pump testing

[ContractorDave]

Has anyone tried using one of those Ultrasonic Transit Time flow meters for fire pump testing? I understand the limitations of using bypass loops to do flows but sometimes you just can't go dumping a ton of water onto a frozen down town street. I'm looking at something called the NCM-603 which appears to be good for clean water full pipe applications.

Regards
Dave

 

[NJ1]

I am not sure if any AHJ will allow this device to be use. It looks interesting though.

 

[pipesnpumps]

Unless they are much improved in the last couple years, in my experience (trying to measure process flowrates) those meters are highly inaccurate.. Vibration and turbulence makes the reading jump around. Alot. Its going to be a case of eyeballing the mean, as it jumps from say 700 up to 1000 gpm..

Basically you will be able to confirm it is pumping.. But thats about it.

 

[ContractorDave]

Thx for the input.

Some of these I've seen advertise a specific accuracy rate (to within 1%) But really, how accurate is a pitot? Even the Hosemonster, whose pitot is fixed for optimum results, jumps all over the place (I haven't tried it with the remote reading kits that presumably might reduce vibration).

Regards
Dave

 

[MGXFP]

With flow in a fully turbulent regime, accuracy can be elusive.

 

[NJ1]

Right. Besides these device must be UL and FM listed for Fire Protection Equipment Testing.

 

[ContractorDave]

I'm going to have to call you on that one NJ. Or at least ask you for citation. Going over the Hosemonster website site for instance, I find no reference to anything other than an FM listing for flow rate accuracy. Whatever that might mean. I see nothing under 25, ch 4 - 2011 ed, and specifically 4.5. Pitot tubes are not listed. I buy and maintain fairly expensive gauges for testing purposes but they are not listed, nor does a quick google lead me to any such device (for testing that is... Ashcroft for example does have gauges listed for fire service). I have my gauges calibrated annually and keep certificates filed, and note the particular test kit number and serial numbers of the kits used on inspection reports, but I do that out of prudence: if I'm asked to justify how I attained certain test results, being able to show I have accurate equipment is a good start. Actually I'm somewhat puzzled by the dearth of information or requirements regarding this, especially in 25. The FPH (20th ed) is silent on the matter also, and actually this is where I had hoped to find a lot more information related to testing practices and the equipment used.

Regards
Dave