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BEAM PLUS FOR NEW B UILDINGS APPENDICES
V ERSION 1.2 8.2 BASELINE BUILDING MODEL
Copyright © 2012 BEAM Society Limited. All rights reserved.
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8.2 BASELINE BUILDING
MODEL
8.2.1
8.2.2
8.2.3
8.2.4
8.2.5
8.2.6
8.2.1 ENVELOPE DESIGN
FEATURES
The characteristics to be incorporated into the Baseline Building model
include:
 envelope design features;
 indoor design conditions, ventilation rates, occupation densities
and usage patterns;
 internal load intensities and usage patterns, and
 performance of air-conditioning systems and equipment.
The Baseline Building model shall satisfy the minimum requirement of
relevant regulations, code of practice, or those that are regarded in
local practice as the basic requirements.
The Baseline Building model should not have skylights, even if there
are skylights in the Assessed Building.
8.2.2 COMMERCIAL
BUILDINGS/HOTEL
BUILDINGS
The regulatory control over the overall thermal transfer value (OTTV) of
new commercial and hotel buildings is taken as the benchmark
envelope design for these two types of building. The envelope of the
Baseline Building model will be assigned with characteristics that
comply with the OTTV requirement as stipulated in Buildings
Department’s Practice Note APP-67 [1]. Calculation of OTTV shall be
based on the method and data given in the Code of Practice for Overall
Thermal Transfer Value in Buildings [2]. Since, according to this OTTV
calculation method, the heat gain from fenestration dominates the
OTTV of a building, adjustment of the envelope characteristics from the
‘as designed’ condition to the baseline condition shall be made by
varying the fenestration area at the external walls or roofs.
The modification of the envelope design of the Assessed Building into
that of the Baseline Building model shall preferably be made through
adjusting the window-to-wall area ratio (WWR, the ratio of the total
window area in the building facade to the total facade area). The WWR
shall be adjusted such that the OTTV of the envelope of the Baseline
Building model will just meet the relevant regulatory requirement (24
W/m2 for a building tower and 56 W/m2 for a podium).
8.2.3 RESIDENTIAL BUILDINGS The default WWR area ratio of the Baseline Building model shall be 0.4,
while the materials for facade construction are described in table 8.2.
The annual energy use and maximum electricity demand for the
Baseline Building model should be found by taking the average of the
results generated by 4 separate simulations: 1 with the building in its
actual orientation and 3 others with the entire building rotated 90, 180
and 270 degrees from the actual orientation.
In predicting the annual energy use and maximum electricity demand
for the Assessed Building, all components of the building envelope,
1 Buildings Department. PNAP APP-67. Energy Efficiency of Buildings Building (Energy Efficiency) Regulation. August 2011.
2 Buildings Department. Code of Practice for Overall Thermal Transfer Value in Buildings 1995.