ISO TS 16491-2012 pdf free download.Guidelines for the evaluation of uncertainty of measurement in air conditioner and heat pump cooling and heating capacity tests.
5 Method of calculation
5.1 CalibratIon
This value Is even in the cbration certitcale, This value is the calb-abon uncertainty whidi takes nb, account the reference instiurnent and the cahbraled
msburnent The caleratron uncertanty shell beats cordbdence level 01 at least 95 %.
5.2 CorrectIon
This quantly concanis here the cratIon correction.
If lies callbraben correctsln is apptad on the jaw measurement of the Instrument tivougli a modalisalon cxve. this term th. maximum difference between th. correction model and the calSiration results If no comaction is appl.d on the raw meesurernent of the rnstru.n.nf. this correction is linearly add.d to the .xpend.d measurement uncertainly
5.3 (instrumental) drift
This value is calculated as the difference ii succ.sIwe calf,rabon corrections
5.4 Stability
The quansty is genecaly a mean of several instantaneous data measured in a given penod of Dma. The uncertainty component due 10 stabIlity is calc&ieted as the standerd devialon 01 the enlantaiecus measurements, and the alanderd uncertainty of the mean value is defined as this standerd deviation divided by the square root of the number of recorded data.
5.5 UncertaInty due to the lack of homogeneity
Th. uncertainty component due to homogenety is calculated as the standerd devIation ci the Individual measurements, and the standerd uncertainty of the mean value is defined as this standa-d deviation divided by the square roof of the number of probes.
6 Explanatory notes useful In laboratory application
6.1 Unc.rtalnty
No measurement of a real quantity i be exact: there is always acme error involved lithe measurement errors may arise because of measurvig nsvumenb riot being exact because the 000dbloris of the lest are not precise, or to, many other reasons. eduding truman error. Th. lêaty magothx)e of this error in measurement ii known as the uncaibenty. Unoeruarty may be expressed as a rang. of lest results (cg 10kW ± 0.1 kW). eras a freceori or percentage of th. lest result (e.g. 10kW 1 %).
6.2 Contld.nce level
Conl’id.no level refers to bra probabaty that the true rearM of a measurement ties whim the range stated by the urr1alnty For .xem, S the maasurem of a power giv.n as 10.0 tiW * 1 % at a confidence bust of 95 %, ties means that there is not more than 5% probability that the true Value of the power is outside the range 990kW to 10.10 kW. A ccnttdence level of 95% is uwaly used Ion engwraerng measurements: Ibis provides a good compromise between rehabiley of msasiwevneris and the cost of makmg those measurements.ISO TS 16491 pdf download.