Carbon Emissions Calculation Method

The Carbon Emissions Calculation Method involves a deeper level of analysis than the two preceding methods. The comparison of carbon emissions for the actual and notional buildings must normally be performed using simulation, and tools for this are provided elsewhere in the <Virtual Environment>. However, certain requirements of the Carbon Emissions Method can be tested in a straightforward manner, and these requirements are included within the automated Part J analysis.

 

 

The requirements of the Carbon Emissions Method are set out in Part J paragraphs J8.7, J8.8, J91, J10.1 and J14.1.  Paragraph J8.7 states

 

"To comply with this method the thermal insulation of the fabric and the efficiency of the building services systems must be such that the annual carbon emissions from the building are not more than from an equivalent notional building designed to comply with the Elemental Method; except - when using this method the standards for building services systems in J11, J12 and J13 may be ignored."

 

Tools for calculating carbon emissions based on simulated performance of the actual and notional buildings over a typical year are provided elsewhere in the <Virtual Environment>.

 

The notional building must be shown to comply with the Elemental Method in respect of insulation, air infiltration and lighting requirements. The Part J software can be used for this task.

 

 

"When using this method the U-value of any building element must be in accordance with the table to this standard.." (Part J, paragraph J8.8).

 

The Carbon Emissions Calculation Method imposes certain limits on the U-values of roofs, walls and floors. These checks are the same as those applied in the Heat Loss Method.

 

 

"The building's fabric must be constructed to minimise thermal bridges and gaps in the insulation layer(s)..." (Part J, paragraph J9.1).

 

"The infiltration of air into a building through extraneous air paths must be limited as far as is reasonably practical."  (Part J, paragraph J10.1).

 

These requirements cannot be analysed in software but are included for completeness.

 

 

"The building services installation required to comply with this Part must - a. be capable of operating at the manufacturer's specified efficiency; and b. incorporate adequate provisions for testing and commissioning to be carried out satisfactorily."  (Part J, paragraph J14.1).

 

"Written information must be provided for the building's occupier on the installed building services plant and controls required to comply with this Part, their method of operation, maintenance requirements, and details forecasting annual energy consumption for the building."  (Part J, paragraph J14.2).

 

These requirements cannot be analysed in software but are included for completeness.

 

Paragraph 8 of the Introduction to the Technical Standards document^[1] stipulates that Part J should be read in conjunction with Part G (condensation), Part H (sound insulation) and Part K (ventilation), and refers to further documents covering these topics.