Action limits:
implementation of monitoring the stability of the results of measurements of the mass fraction of moisture.
The result
of the control procedure B, %, is calculated by the formula
B ^ ^/d2 + i
where
og is the value for the corresponding
method and measurement range;
conditions (8) find out the causes that led to unsatisfactory results and eliminate them.
d2or = 1.128
og,
w = \W jW 2\.
Ds — limits of absolute error according to the comparison method, %.
(C)
and eliminate them.
where A are the limits of the absolute error for the corresponding measurement
range according to the table
(7)
5.8.3.2 Shewhart control chart parameters for repeatability stability control Calculate
the following parameters
for Shewhart control charts for repeatability stability control1).
UCL -D 2or 3.686
og, LCL
- absent.
(6)
d2 is the coefficient for calculating the midline;
d2 = 1.128
with the number of parallel determinations equal to two.
B \u003d W - C,
It is recommended to control the stability of the results of measurements of the mass fraction
of moisture in mineral
fertilizers and middlings obtained during the control according to 5.8.1 or 5.8.2 in accordance with the provisions of [2]1).
Control procedures and their frequency are indicated in the quality manual or in the contract for the supply of products. If
such a frequency is not indicated, then the recommendations [2] on the choice of the number
of control procedures
depending on the volume of analyzed samples are followed.
If condition (8) is not met, the control procedure is repeated.
Upon repeated failure
middle line
6
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