1.0.1 With the view to implementing national policies of conserving energy, protecting the environment effectively, reducing discharge of greenhouse gases and further realizing energy conservation and emission reduction, this standard was revised based on "Design Standard for Energy Efficiency of Public Buildings" (DB11/687-2009) according to the actual conditions of Beijing to improve energy utilization and reduce building energy consumption.
1.0.2 This standard is applicable to energy efficiency design for newly-built, extended and rebuilt public buildings in Beijing. For buildings under the following conditions, the applicable conditions for them in this standard shall be determined according to the following principles:
1 Temporary buildings with service life less than 5 years may not comply with this standard compulsorily.
2 Independent office buildings and living supporting buildings in factory areas shall comply with this standard.
3 As for non-industrial part built near factory buildings, such as office buildings, if the proportion of its area in the whole building area is larger than or equal to 30%, and the area is larger than or equal to 1000 m2, then the non-industrial part shall comply with this standard; if the proportion of area of non-industrial part in the whole building area is less than 30%, or the area is less than 1000 m2, it may not comply with this standard.
4 As for the residential part in public buildings, if the proportion of its area in the whole building area is larger than or equal to 10%, and the area is larger than or equal to 1000 m2, then the residential part shall comply with the current Beijing Local Standard "Design Standard for Energy Efficiency of Residential Building" (DB11/891), and the public part shall comply with this standard; if the proportion of area of residential part in public buildings in the whole building area is less than 10%, or the area is less than 1000 m2, it shall comply with this standard.
5 Buildings used for enterprise R&D and software development, etc. shall comply with this standard.
1.0.3 The following buildings may comply with this standard partially;
1 Buildings without HAVC facilities shall comply with the requirements of this standard except those in Chapter 3 and Chapter 4; as for buildings with only some rooms provided with heating or air conditioning, only the local areas where the rooms provided with heating or air conditioning are located shall comply with this standard.
2 The following buildings shall comply with the requirements except of Chapter 3 about buildings and building thermal design:
1) Independently built substations, boiler rooms, cooling stations, pump stations and other power stations;
2) Electronic information system room.
1.0.4 Energy-efficient design of public buildings shall reduce energy consumption of buildings via the following means based on the climatic characteristics of Beijing according to the requirements of this standard, under the premise of ensuring indoor environment quality:
1 Optimize building design, improve building envelope thermal performance and reduce building heating and air conditioning load;
2 Reduce the energy consumption of cooling/heating source system and energy transmission and distribution system via energy efficiency design of heating, ventilation and air conditioning system;
3 Reduce the energy consumption of building water supply and drainage, lighting and electrical systems via energy efficiency design of water supply and drainage and electrical systems.
1.0.5 Construction drawing design document shall state the energy-efficient measures taken for the engineering project by systems, and should include the basic requirements of energy-efficient operation.
1.0.6 The energy efficiency design of public buildings shall comply with both this standard and the relevant requirements of relevant current policies, regulations and standards of the nation and Beijing.
2 Terminologies
2.0.1 Shape factor (S)
The ratio of the external surface area ∑F of building in direct contact with outdoor air to the volume V0 enclosed by it.
2.0.2 Single facade window to wall ratio (ML)
The ratio of the area of transparent part of certain single facade of building and the non-transparent external door opening to the total area of this facade.
2.0.3 Total window to wall ratio (MLZ)
The ratio of the total area of transparent part of each facade of building and the non-transparent external door opening to the total area of each facade.
2.0.4 Transparent part
The external building envelope structure through which visible light may transmit directly into room, including transparent materials and frame of window, skylight (daylighting roof), glass external door and transparent curtain wall, etc.
2.0.5 Visible transmittance
The ratio of luminous flux of the visible light transmitting through transparent materials to that of the visible light projected on their surfaces.
2.0.6 Solar heat gain coefficient (SHGC)
It is also referred to as total solar energy transmittance. It is the ratio of solar radiation part becoming indoor heat gain after transmitting through transparent part of building to the solar irradiance projected to transparent part of building. Solar radiation part of indoor heat gain includes the heat gain of solar radiation through radiation transmission and that of solar radiation absorbed by members then transmitted to room.
2.0.7 Shading coefficient (SC)
The ratio of solar heat gain transmitting through building transparent part and its shading facilities to that transmitting through normal glass (3mm-thick transparent glass) of the same area under the same condition.