(i)
Physical constraints: it is not reasonably practical to install a heat meter or steam measuring equipment98.
(ii)
Reasons of safety: it is not safe to read the heat meter in the required location98.
(iii)
Environmental conditions: the environment in which the meter is positioned might affect its readings98.
(iv)
Metering would provide less accurate results than a heat loss calculation.99
(v)
It is financially overly burdensome to install additional meters. From collaboration with industry, Ofgem have taken this to be where the cost of installing any additional required heat meters would be more than five per cent of the total plant installation costs, or greater than ÂŁ50,000.100
(vi)
Negligible ineligible heat losses: where the associated annual heat loss from external pipework would equate to less than ÂŁ100 in RHI periodic support payments.101
7.44. In order to assess whether heat loss may be disregarded, the HLA tool will first determine whether external pipework can 102 . The regulations set criteria for classifying external pipework as properly insulated. The piping must be insulated so the maximum heat losses set in British Standard BS5422:2009103 are not exceeded. Those heat losses should be calculated using the equations and principles in BS EN ISO 12241:2008104. Question 1 of the HLA will determine whether an individual pipe length105 meets this regulatory definition. 7.45. If Question 1 confirms that an external pipe length can be considered properly insulated, the associated heat loss can be disregarded in the following circumstances: for each individual external pipe length 10m or less in length, and/or
98 99
Regulatio
100 101
in certain
102 103
BS 5422:2009: Vessels, Ductwork and Equipment Operating within the Temperature Range -40oC to +700o 104 105
Note that an external pipe length can be above ground or buried and can exist in relation to single or multiple buildings.
If you need help Telephone: 0845 200 2122
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Ofgem.gov.uk/RHI 79