Office Building Icarus, Nikolay Liliev Street, ZLE (zoned landed estate) I-663, quarter 239, Lozenets locality, city of Sofia.
   Business Building is situated on accessible and communicative place by Hotel "Hemus", close to "European Union" Metrostation, after "National Palace of Culture" and Business Centre "City Center Sofia" with quick and easy access to the Centre of Sofia
       1. Location and description.  An office building with an underground garage on 4 and 5 floors in , under observation of the parameters of an Hm planning area – max. building density 50%, max. Cint 2.3, min. area of greenery 35%, located in an estate with an area of 364 m2.
Borders of the plot:
To the north-west: N. Liliev Street
To the south-west: ZLE X-201
To the south-east: ZLE ХIХ-460
To the north-east: ZLE XV-463 and ZLE VII-462.
Within the estate, the parking places necessary pursuant to the norms are located in an underground garage accessible with a ramp, grass plots and high tree vegetation are located. Along the estate border, a metal openwork fence with a height of 2.2 m above the terrain will be built.
The access for visitors is ensured from the street located on the north-west; from it, the access of employees to an underground car park is also realized by means of a one-way ramp in the north-west corner of the building, with the traffic being organized with a set of traffic lights.
      2. 3D town planning solution The design development is for an office building consisting of a basement, a ground floor and 4 floors.
The category of the building is 4 pursuant to Art. 137, para. 1, it. 4, letter “b” of LTP.
The building meets the requirements of Regulation No. 4 of 1 June 2009 on Design, Execution and Maintenance of Construction Sites in Conformity with the Requirements for Accessible Environment for the Population, including for the People with Disabilities, as well as the Requirements of Regulation No. of 22 December 2003 on Rules and Norms for Planning of the Individual Types of Territories and Planning Areas.
     3. Content of the design and functional solution 
An underground car park with 10 places is located in the underground floor. At this level, technical rooms and a room for a cleaner are also located.
The ground floor contains a lobby with reception/security and an accessible toilet, a café with a bar and a storeroom to it, an office with a toilet.
Two rental modules with toilets and kitchenettes are located on the 1st floor.
Two rental modules with toilets and kitchenettes are located on the 2nd floor.
One rental module with toilets and a kitchenette is located on the 3rd floor.
A study as an extension of the rental module on the 3rd floor is located on the 4th floor.
Loggias and roof terraces have been provided for to each module.
       4. Materials and executionFlooring:
- Office areas – carpet plates 50/50 cm on a raised floor with plates 60/60 cm.
- Floor in lobby and café – ceramic granite (Granitogres) slabs 60/60 cm on a raised floor with plates 60/60 cm.
- Lift and staircase landings – ceramic granite (Granitogres) slabs.
- Toilets, kitchens – terracotta slabs.
- Garage – flooring made of multilayer polyurethane with waterproofing properties on cement coating.
- Auxiliary rooms in the basement – cement coating.
- The exposed walls will be executed of low-flammability-point façade panels with heat-insulation properties, 8 mm thick, flush mounting.
- On the inner side of the façade walls, plasterboard lining with rock wool will be put additionally.
- The walls of the technical rooms will be with the necessary limit of fire resistance, in conformity with the function.
- The walls of the toilets will be executed with moisture-proof plasterboard.
- The suspended ceilings in the offices will be executed of metal perforated plates with acoustic inserts, with plasterboard stripes according to design.
- In the technical rooms and the stairwell, the ceiling is with exposed concrete.
Doors and windows:
- The execution of the doors and windows, the type of glazing and the method of opening will meet the functional requirements, will conform to the degree of security for this type of buildings and the anti-fire norms. The glazing will be with insulation against penetration of solar radiation in the ultraviolet and infrared spectrum, guaranteeing a total coefficient of thermal conductivity of the window group / system of not more than 1.7 W/K · m2 and a solar factor of 0.6.
- The doors of the technical rooms will be of metal, with a limit of fire resistance in conformity with the anti-fire norms.
     5. Energy efficiency and systemsThe building materials, products and articles that will be used for the construction of the building ensure the necessary energy efficiency.
Eight areas subject to heating, cooling and ventilation – “Lobby and stairwell”, “Café”, “Office No. 1”, “Office No. 2”, “Office No. 3”, “Office No. 4”, “Office No. 5” and “Office No. 6”, have been differentiated in the building.
For each differentiated area in the building, independent heating, ventilation and air-conditioning systems have been provided for.
The VRV multi-split systems with direct evaporation of DAIKIN – Mini VRV (RXYSQ-P) and Heat Pump (RXYQ-P), have been laid down.
The heating and the cooling of the rooms in the areas is performed by means of fan coil units, VRV system, for exposed floor mounting, exposed ceiling mounting or concealed ceiling duct mounting.
For each area, an autonomous ventilation system that ensures the amount of processed air, necessary to achieve comfort, has been provided for.
The air processing is ensured by a recuperative ventilation unit, VAM-FA DAIKIN system, with more than 50% utilization of the exhaust air temperature. For additional processing, a duct fan coil unit, VRV system, connected to the multi-split system corresponding to the area, has been provided for.
The control and monitoring of the heating, ventilation and air-conditioning systems may be performed individually for each fan coil unit, by areas and totally for the whole building.
Respective exhaust ventilation systems for the underground car park (pursuant to sanitary norms and VSRSH), the café, the toilets and the kitchenettes have been provided for.
Fire-isolating flaps with a fusible element have been provided for during penetration of air ducts through fire-protection barriers.
The use of heat pump units, VRV system (with high values of ERR, COP и ESEER), for year-round provision of the parameters of the microclimate in the building and the recuperation of the released air contribute significantly to the reduction of the energy costs for maintenance of the microclimate and increase considerably the energy efficiency of the building.
    6. Power supply 
The external power supply of the building and the measurement of the electric power is in conformity with the instructions of CEZ Distribution. A common Main Distribution Board located in an independent room of the building basement has been provided for.
Total operating power = 91.5 kW.
Operating power backed up by a DG = 26.5 kW (33 кVА)
In the Main Distribution Board, common control measurement with two-rate meters has been provided for.
The floor distribution boards of each rental unit are supplied from the Main Distribution Board.
For the café on the ground floor, an independent control measurement with two-rate meters in the Main Distribution Board has been provided for.
REDUNDANT POWER SUPPLY – a diesel generator (DG) installed in the building basement, complete with ALT board, has been provided for.
    7. TELECOMMUNICATIONS AND STRUCTURED CABLINGFor each floor, a place for a telecommunications cabinet in the proximity of the floor distribution boards has been provided for. In the present design, horizontal and vertical routes with trays for telecommunications conductors to all floors have been provided for.
On the floors, the systems will be laid on trays in the suspended ceiling and in the raised floor. In the area of the raised floors, the cables shall be fixed with ties. The vertical and horizontal cabling from the building distributor to the floor distributors, as well as to the workplaces will be performed by a specialized company.
At all transitions, inspection boxes for easier operation of the system shall be provided for. In the floor boxes for each workplace, 2 RJ45 sockets each have been provided for.
   8. WaterproofingThe roof and all enclosing structures will meet the effective heat engineering requirements and will ensure the necessary waterproofing. The execution of the facades and the roof will be completed with all necessary elements: insulating, dewatering, etc.
For waterproofing of the foundations and the underground parts of the building, the construction of a waterproofing tank between the diaphragm walls of the reinforced excavation and the backup reinforced-concrete walls of the building structure, made of prehydrated high-density bentonite diaphragm laminated with geotextile and polyethylene foil, which tank at its upper parts is connected with EPDM moisture barrier, with the execution having to conform to BDS 14825:1979 “Waterproofing of underground parts of buildings and facilities. Main design principles” and all relevant standards shown in Appendix No. 1 to Art. 9, para. 6 of Regulation No. 2 of 6 October 2008 on Design, Execution, Monitoring and Acceptance of Waterproofing and Waterproofing systems of Buildings and Facilities, has been provided for.
The roofs are flat and are of three types – with greenery, terrace roof and a flat roof above floor 4.
- The roofs with greenery are flat, with internal dewatering. The so called “inverted” roof, in which the EPDM moisture barrier is laid under the heat insulation, and a protective and draining root-resistant layer will be executed between the heat insulation and the soil layer, has been provided for;
- The terrace roof is executed inverted, the EPDM moisture barrier is glued to the concrete for inclination, heat insulation made of XPS with geotextile is laid on it, ceramic granite (Granitogres) slabs are put on the top on adjustable plastic legs;
- The above floor 4 is executed with EPDM moisture barrier on rock wool mats with which the inclinations are formed;
The execution shall conform to all relevant standards shown in Appendix No. 1 to Art. 9, para. 6 of Regulation No. 2 of 6 October 2008 on Design, Execution, Monitoring and Acceptance of Waterproofing and Waterproofing systems of Buildings and Facilities.
   9. Lift systems1 lift – passenger – class I for the administrative part pursuant to Art. 6, para. 1, with mechanism in the shaft, is located in the building. The lifts and the staircase landings in front of them are in conformity with Art. 50, Art. 51, Art. 52 of Regulation No. 4/1 June 2009 on Accessible Environment and conform to the overall dimensions under the appendices to Regulation No. 2/8 June 200 on Lift Systems.
   10. Noise protectionAll walls, floors and doors will be in conformity with the minimum requirements for insulation from air and impact noise pursuant to Appendices No. 3 and No. 4 to Art. 19.
Technical and economic indices
During the building design, the following technical and economic indices have been achieved:
Floor area (FA) –                                                       143.11 m2
Gross floor area (GFA) above elevation 0.00 –             790.12 m2
Total gross floor area –                                             1246.87 m2
Built-up volume –                                                     4166.31 m3
Planning indices:
ZLE I-663, quarter 239, Lozenets locality, Sofia 364
No. Indices Planning indices
Planning indices
Value Area (m2) Value Area (m2)
1 Cint (GFA) 2.3 837.20 2.17 790.12
2 Density (FA) 50% 182.00 39% 143.11
3 Greenery 35% 127.40 37% 135.85
4 High vegetation 17.50% 63.70 18% 64
Necessary number of parking places – 10, located in an underground car park.