NFPA 99 - Operational Test Flow Rate Accuracy

[johnschimandle]

I'm new to NFPA 99 standards and looking for some information regarding the required accuracy of flow measurements during the operational test for hospital gasses as specified in NFPA-99 2012 section 5.1.12.3.10. This section specifies a number of operational tests that require a certain flow rate while measuring the gas pressure. NFPA-99 2012 section 5.1.8.1.7 states that all pressure and vacuum indicators used for testing must be accurate to 1% of full scale or better. I can't seem to find any section in NFPA-99 2012 that specifies the flow rate accuracy.

The reason I'm asking is that 1% full scale pressure transducers are fairly easy to find and relatively low cost ($20-$40). Gas Flow sensors at 1% full scale accuracy are very difficult to find and extremely expensive (> $1500) and also require regular calibration. Flow sensors in the in the 3.5% accuracy range are moderate in cost ($120) and do not need calibration.

So what is the required accuracy for flow rate in the operational test?

 

[stookeyfpe]

I see no requirement in 2012 NFPA 99, Section 5.1.8.1 for the measurement of flow. When I read the section in its totality, it is only establishing requirements for pressure (positive and vacuum), not flow. Section 5.1.8 is titled Pressure and Vacuum Indicators, which reinforces that pressure measurement is intent of NFPA 99. A required flow rate may be specified in the construction specification but its not a requirement of NFPA 99. Annex B 5.2.18 addresses the issue of flow rate, but the language is only advisory and does not have the force of law if NFPA 99 is adopted by a jurisdiction.

 

[johnschimandle]

Thanks for the information on flow rate tolerances. NFPA 99 does make reference to specific flow rates in 5.1.12.3.10.2 though 5.1.12.3.10.5 for operational testing. I'm in the process of designing an instrument to verify compliance with this section and I'm trying to understand how tightly gas flow must be controlled during these tests.

I would think that gas flow rate control of 5% should be sufficient but was not sure and I could not find gas flow measurement tolerance specified in NPFA 99.

 

[stookeyfpe]

Flow rate must be part of your specification because it's not required by NFPA 99. You should read my Annex B reference. Good luck .