Section 6: Room surrounding surface

Room surrounding surface - Term definitions

After the common data of a room have been defined, conse­quently the individual building elements of the room surrounding surface has to be entered. This is done by the so called room ta­ble where the corresponding building element codings are regis­tered line by line and completed by the necessary data. The sum of the building elements which differentiates a room from the neighbouring room or outside or against earth are denominated as room surrounding surface. Each building element is subject to different influences (e.g. adjacent temperatures etc.) which have to be described in detail.

Building element coding

The building element coding consists of four signs. The first two signs are indicated according to EN 12831, the last two signs show any number from 00 to 99:

• EWI00 - EWI99 = Exterior window

• ED00 - ED99 = Exterior door

• RW00 - RW99 = Roof window

• EWA00 - EWA99 = Exterior wall

• RO00 - RO99 = Roof

• CE00 - CE99 = Ceiling

• FL00 - FL99 = Floor

• IWI00 - IWI99 = Interior window

• ID00 - ID99 = Interior door

• IWA00 - IWA99 = Interior wall

The building element coding can either be entered by hand or called on from the building element catalogue. The calling on happens by a click on the icon right next to the input field or by using the button Enter.

Neighbouring side

The following choice possibilities are at the disposal for the choice of the situation on the neighbouring side of the building element:

• Building element borders on exterior air

• Building element borders on unheated adjacent room

• Building element borders on heated adjacent room

• Building element borders on earth

The building elements which border on heated adjacent rooms remain unconsidered for the calculation of the transmission heat losses of the building. According to standard all building elements EWA, EWI, E, DO, ED are characterized as building elements against exterior air.

«- Note:

Through the input of the following letter and ENTER the neighbouring side of the building element can be entered via the keyboard:

e = exterior air

h = heated room

u = unheated room

e = earth

According to choice of the neighbouring side the nec­essary input data are interrogated.

Direction

The direction must not consequently be entered as this indication is only for information, that means that it has no influence on the calculation. The following choice possibilities are at the disposal:

• S: Building element directed to South

• SW: Building element directed to Southwest

• W: Building element directed to West

• NW: Building element directed to Northwest

• N: Building element directed to North

• NE: Building element directed to Northeast

• E: Building element directed to East

• SE: Building element directed to Southeast

• H: Building element directed horizontally

Number of similar building element

If the room has a number of completely identical surrounding sur­faces (building elements e.g. same windows), register the data of the building element only once and set the number of the identical building elements.

Width, height/length and surface of the building element

The dimensions of the building element (of the surrounding sur­face) have to be entered. The building element has to be calcu­lated from this and is no input value.

The national annex settles which dimensions have to be entered for the building elements.

In Germany the prescription says that exterior dimension must be applied. Consequently the room interior dimension plus the com­plete exterior wall thickness respectively half of the interior wall thickness have to be considered at the input of the wall.

For windows and doors the inside dimension of the wall opening has to be indicated, for the heights of the wall the storey heights (inside room height and ceiling thickness) have to be registered.

«- Note:

Switch-on respectively switch-off the assistant for the calculation of chain dimensions by clicking on the switch Chain dimensions. Depending on the kind of building element (e.g. wall, ceiling etc.) the assistant supports you during the calculation of chain dimen­sions according to each situation; that means that the assistant calculates the necessary building element from entered room interior dimensions and adjacent wall thicknesses.

If width respectively height/length are not expressly known respectively the surface of the building ele­ment has an irregular geometry, then the surface as­sistant can be called on in the field Surface. It also calculates the mean dimensions of the irregular build­ing element surfaces besides the surface contents.

Outlet surface

If a „ - " is entered into the field, then the building element surface is considered as outlet surface from the next building element which has no outlet surface. It has to be noted that the sum of all outlet surfaces has to be smaller than the surface itself. Further­more no room surrounding surface can stand as last building element.

Choice possibilities:

• Outlet surface

• empty: no outlet surface

«- Note:

The outlet surfaces are always entered before the gross surface. It can be alternatively decided in the printout of the room. If the first outlet surface or the gross surface should be designed.

Correction factor for thermal bridges

The heat transmission coefficient U is corrected by a factor at ex­terior surfaces respectively at unheated adjacent rooms and building element at earth. But this is only the case if it is re­nounced on a detailed thermal bridge proof. In this case a correc­tion of the U-value is not applicable and the thermal bridges have to be registered with their heat transmission coefficient referring to length.

«- Note: