Written evidence submitted by Paul Davies
1. Along with my Partner, I am the leaseholders
of The Cricketers Arms, Bedford, a Punch lease that was negotiated
in 2005.
2. I am a degree qualified electronic engineer
with many years experience in the design and operation of measurement
systems, I submitted to the last sitting of the committee my concerns
of the use of the Brulines flow monitoring system by the pub companies
and the potential for wrongful accusation of buying out of tie
due to serious flaws in the system.
3. The committees recommendation in the follow
up report 4 March 2010 was
"that the Government, through the National
Measurement Office, urgently clarifies the position of beer flow
monitoring equipment in relation to the Weights and Measures Act
1985. Such equipment must be included under the Act for calibration
and verification purposes."
This was modified in the Government's response to
"Government is clear that the industry should
voluntarily ensure that all such measuring equipment is calibrated
by the National Measurements Office. However should the industry
fail to do so within a reasonable time frame this will result
in Government prescribing the equipment to ensure fairness."
4. In response to this, Brulines commissioned
the National Measurement Office (NMO) to undertake tests on the
i-draught and DMS versions of their flow monitoring equipment.
These Brulines designed and commissioned tests were not the voluntary
calibration the Government was requesting.
5. The results of these tests were published
by the NMO without any conclusions by the NMO. The results were
analysed by Brulines and their own conclusions were published
in their "Comprehensive Guide To Flow Monitoring". They
concluded in their analysis that the equipment is fit for purpose.
The NMO drew no such conclusions.
6. Brulines use a very simple method of calculating
the error for each test. They sum the errors giving equal weight
to each point. In this method a large negative error will be canceled
by an equally large positive error giving a false impression of
accuracy.
7. To give an example of this, the NMO Test 3,
Brulines give the error for this test as -0.71% for both the i-draught
and DMS systems. As can be seen from the graph of the percentage
error the DMS system saw huge positive and negative errors.
The fact that these cancel each other may be coincidental,
further testing should be done to confirm that a large negative
is always cancelled out with a large positive as Brulines suggest
is the case.
8. In response to Brulines' Comprehensive Guide
to Flow Monitoring I undertook a more scientific analysis of the
NMO results and Brulines Comprehensive Guide To Flow Monitoring
and concluded that both the i-draught and DMS systems are not
stable or repeatable enough to conclude that they are fit for
purpose.[23]
9. The systems do not cope well with every day
dispense occurrences, such as barrels running out and entrained
gas. Heavy reliance is placed by Brulines on their "robust
auditing" to rectify the failings of the systems. To date
there is nothing to support that this robust auditing process
will recognise and correct the problems encountered in the NMO
testing or use in the field.
10. I include my more detailed documents analysing
the NMO test results and Brulines Comprehensive Guide To Flow
Monitoring. I also include my explanation of the calibration "k"
factor which is so important in the operation of such systems.[24]
11. I apologise for the length of these documents,
but they are considerably shorter than the NMO report and Brulines
Comprehensive Guide To Flow Monitoring.
19 June 2011
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