When you set up a project, which will be used with the PartL program, you should check the following:

1. The Favourites list has been superseded by the Standard rooms list, which contains standard room data for new building and room types which can be used with PartL. You MUST visit each room (using the Room data or CAD input modules) and select the required new Standard building/room from the building and room types displayed. You DO NOT have to press the Set to Standard room button. When you run the PartL program, the SBEM calculation automatically uses standard design information based on the Standard building/room information set up for each room. These values are imported automatically from the NCM Construction database. The design data that you have entered for rooms is not used for the PartL calculation.
2. You should check all glazing that is used with the project has the total solar transmittance (T-Solar) correctly defined, as this is used in the calculation (see below).
3. All U values and material thermal properties are taken from the Fabric database except exposed ground floor U values, which are as specified in the Room data module for the exposed ground floor. This is to enable you to define exposed ground floor U values which may depend on building shape and edge losses, rather than just construction details.

Special surface types - In order to use surface types such as vehicle doors, that can be recognised during the PartL analysis, we have provided a facility to recognise special surfaces if you include the following keywords when you set up the description of a relevant surface.

• a) External personnel doors - define as a wall or a window, which has the keyword DOOR within its description. In the case of windows, also include the code WALL=n, where n in the index of a wall construction. This wall construction will be used for the door.
• b) Vehicle access doors – define as a wall or a window, which has the keyword VEHICLE-DOOR within its description. In the case of windows, also include the code WALL=n, where n in the index of a wall construction. This wall construction will be used for the door.
• c) High usage entrance doors – define as a wall or a window, which has the keyword HIGHUSAGE-DOOR within its description. In the case of windows, also include the code WALL=n, where n in the index of a wall construction. This wall construction will be used for the door.

This could be used as a wall within the project to set up vehicle access doors and would be recognised by the PartL package when analysing surfaces and U values.

To demonstrate compliance with PartL2A, five criteria are identified in the legislation, these are:

1. For England, Wales, Scotland and Northern Ireland, the proposed building carbon dioxide emission rate (BER) must be less than or equal to the Target emission rate (TER). For the Republic of Ireland then the primary energy consumption and related CO₂ emissions must be less than or equal to the energy consumption and emissions of the reference building.
2. Fabric, heating, HWS and lighting to be within specified Design limits.
3. All spaces are considered for solar gain check, including non-air conditioned spaces which were not previously.
4. The building should be constructed consistent with the BER.
5. Building systems should be operable in an energy efficient manner..

This package will perform the following checks to determine whether a project complies with PartL2A.

• - carbon dioxide emissions for the building are computed by automatically running the UK Government Simplified Building Energy Model (SBEM). This CO₂ emission is then compared to the CO₂ emission of a target building, which is automatically set up, using information relating to the actual building.
• Limiting U values – all the constructions that are used for the project will be checked against the limiting U values given in PartL2A Table 4. Checks are made to see if the area-weighted average for each element type exceeds the limiting U value.
• Limiting solar gains – each room is checked to see if the solar and internal casual gains (people, lighting and equipment), averaged over a specified span of time (April – September), and does not exceed gains seen on a reference glazing case.

TER = Cnotional x ( 1 – Improvement ) x ( 1 – LZC)

A notional building is automatically constructed by SBEM from the proposed building using the following:

1. Same size and shape as proposed building
2. Comply with the ‘Energy Performance values’ for fabric and services
3. Having same area of vehicle access doors and display windows as proposed building
4. Excluding services not covered by PartL (eg emergency lighting, lifts etc.)
5. Having the same activity areas and class of building services as proposed building
6. Having occupancy times and design conditions as defined by the NCM activity database
7. Using the same CIBSE weather data as the proposed building
8. Using the same heating fuel as the proposed building
9. Using prescribed U values for elements, thermal bridging, glazing amount, glass transmission and system efficiencies for a notional building (Appendix B)

The insulation levels and HVAC efficiencies in the reference building are identical to the notional building except that certain parameters in the reference building are fixed irrespective of features in the actual building. These aspects are:

1. The heating and hot water service is always met by a gas-fired system.
2. The Reference building has a fixed servicing strategy:
   • Each room is heated to the heating setpoints defined in the activity database.
   • Each room is cooled to the cooling setpoints defined in the activity database.