S.L. 549.78 Art. 2Interpretation.

For the purpose of these regulations and unless the context otherwise requires:

"combustion unit" means any technical apparatus in which fuels are oxidised in order to use the heat thus generated;

"combustion plant" means any plant made up of one or more combustion units. Where a combustion plant is made up of more than one separate combustion unit which, discharge their de facto, waste gases through a common stack, the combination formed by these units shall be considered as a single combustion plant.

In addition combustion units which have been granted a permit for the first time on or after 1st July 1987, or the operators of which have submitted a complete application for a permit on or after that date shall be considered as forming part of the same combustion plant if in the judgement of the competent authority, they are installed in such a way that taking technical and economic factors into account their waste gases could be discharged through a common stack.

In both cases the capacities of the constituting combustion units (excluding those individual units having a rated thermal input below 15 MW ) are to be added up in order to calculate the total Th rated thermal input of the plant; "determinative fuel" means the fuel which, amongst all fuels used in a multi-fuel firing combustion plant using the distillation and conversion residues from the refining of crude-oil for own consumption, alone or with other fuels, has the highest emission limit value as set out in Schedules I, III, and V, or, in the case of several fuels having the same emission limit value, the fuel having the highest thermal input amongst those fuels; "emission limit value" shall have the same meaning as in the Industrial Emissions (Framework) Regulations, and shall be expressed at standard conditions according to the following equation:

101.3 100 20.94 -T O [P] =    s  [P] s M 273.15 P 100 - W 20.94 - O M Where: [P] is the mass concentration of the pollutant at s standard conditions. [P] is the mass concentration of the pollutant M measured at the temperature T in Kelvin (K), at a Pressure P in kilopascal (kPa), at a percentage flue gas water vapour content of W and at a flue gas oxygen content of O . M T is the actual flue gas temperature in K. P is the actual flue gas pressure in kPa. W is the percentage water vapour content of the flue gas. O is the standard oxygen content by volume in the S waste gas which shall be 3% in the case of liquid and gaseous fuels, 6% in the case of solid fuels and 15% in the case of gas turbines or gas engines. O is the measured oxygen content in the flue gas; M "maximum continuous rating" means the maximum output in MW that a generating plant is capable of producing continuously E under normal operating conditions over a period of time which shall not be less than one year;

"rated thermal input" means the rate at which fuel can be burned at the maximum continuous rating of the combustion plant multiplied by the net heat value of the fuel expressed as megawatts thermal (MW ); Th "waste gas" means the carrier gas together with any solid, liquid or gaseous emissions which are discharged with it; the waste gas volume flow rate shall be expressed in metres cubed per hour at standard conditions, i.e. at a temperature of 273K and at a pressure of 101.3 kPa, after correction for the water vapour content, and hereinafter referred to as normal metre cubed per hour or Nm3.hr-1.