Green Building Assessment Standards: Office Building Analysis

This report examines the Green Building Assessment Standards, specifically focusing on achieving the Green Mark Platinum rating for an existing 8-storey office building under the BCA Green Mark for Existing Non-Residential Buildings (Version 3.0). The analysis begins by evaluating the building's current scoring across various categories, including energy efficiency, water efficiency, sustainable operation and management, indoor environmental quality, and other green features. The report highlights the building's current Green Mark Score of 90.56, which qualifies for Platinum rating. However, it also identifies areas for improvement based on a comparison with the BCA Green Mark for New Non-Residential Buildings (Version NRB/4.1) scorecard, where the building scored 94.77 but was awarded GoldPLUS due to specific criteria not being met. The report outlines the prerequisites for achieving Platinum rating, including minimum scores in energy efficiency, the efficiency of the water-cooled chilled-water system, and requirements for natural ventilation and indoor air quality audits. It provides recommendations for retrofitting the building to maximize points in each category and meet the necessary standards for energy and water efficiency to achieve the Platinum rating. The report also mentions the importance of measurement and verification (M&V) instrumentation of the chiller plant. The report concludes by providing recommendations for the building owner to enhance the building's sustainability and resource efficiency to achieve Green Mark Platinum status.

Running head: GREEN BUILDING ASSESSMENT STANDARDS
GREEN BUILDING ASSESSMENT STANDARDS
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GREEN BUILDING ASSESSMENT STANDARDS 2
Green Building Assessment Standards
Question 1(a)
There are four main Green Mark Ratings. These ratings are based on the Green Mark
Score awarded to a building. The four ratings are as follows: Green Mark Certified – Green
Mark Score of 50 - <70), Green Mark Gold – Green Mark Score of 75 - <85, Green Mark
GoldPlus – Green Mark Score of 85 - <90, and Green Mark Platinum – Green Mark Score of 90
and above (Building and Construction Authority, 2016). The Green Mark Score is the total of
scores awarded to different elements of the building that make the building to be energy
efficient, water efficient, environmentally friendly, and have high indoor environmental quality
and other appropriate green features (Building and Construction Authority, 2018). In this
problem, the owner of the building is planning to retrofit an existing 8-storey office building so
as to make it more resource efficient and sustainable for it to achieve Green Mark Platinum
rating under the BCA Green Mark for Existing Non-Residential Buildings (Version 3.0). A
scorecard showing the scoring of the building under BCA Green Mark for New Non-Residential
Buildings (Version NRB/4.1) has been provided. Relevant information has to be extracted from
this scorecard and used to determine the score of the building under BCA Green Mark for
Existing Non-Residential Buildings (Version 3.0). This will help the owner identify appropriate
areas that should be improved and determine the best strategies of improving them so that the
building can achieve Green mark Platinum rating after retrofitting.
The current scoring of the building based on BCA Green Mark for Existing Non-
Residential Buildings (Version 3.0) is provided in Table 1 below:
Table 1: Current scoring of the building

GREEN BUILDING ASSESSMENT STANDARDS 3
Category Max. Points
Allocated
Points
Scored

GREEN BUILDING ASSESSMENT STANDARDS 4
ENERGY EFFICIENCY
Energy Efficiency
ENRB 1-1 Thermal performance of building envelope 5 3.10
ENRB 1-2 Air conditioning system 32 26.21
ENRB 1-3 Natural ventilation/mechanical ventilation - -
ENRB 1-4 Artificial lighting 13 11.70
ENRB 1-5 Ventilation in car parks 4 2
ENRB 1-6 Ventilation in common area 5 4
ENRB 1-7 Lifts and escalators 2 1
ENRB 1-8 Energy efficient practices & features 12 1
ENRB 1-9 Energy policy & management 1 -
ENRB 1-10 Renewable energy 15 4.13
Category Score for Energy Efficiency 89 53.14
OTHER GREEN REQUIREMENTS
Water Efficiency
ENRB 2-1 Water monitoring 4 4
ENRB 2-2 Water efficient fittings 12 8.05
ENRB 2-3 Alternative water sources 3 -
ENRB 2-4 Water efficiency improvement plans 1 -
ENRB 2-5 Irrigation system and landscaping 2 0.67
ENRB 2-6 Cooling towers 2 1.00
Category Score – water efficiency 24 13.72
Sustainable Operation & Management
ENRB 3-1 Building operation & maintenance 4 1.20
ENRB 3-2 Post occupancy evaluation 3 -
ENRB 3-3 Waste management 7 -
ENRB 3-4 Sustainable products 8 3
ENRB 3-5 Greenery 10 3.75
ENRB 3-6 Environmental protection 3 2.46
ENRB 3-7 Green transport 4 2
Category Score – sustainable operation & management 39 12.41
Indoor Environmental Quality
ENRB 4-1 Indoor air quality performance 8 4
ENRB 4-2 Indoor air pollutants 2 0
ENRB 4-3 Lighting quality 5 -
ENRB 4-4 Thermal comfort 2 2
ENRB 4-5 Internal noise level 1 1
Category Score – Indoor Environmental Quality 18 7
Other Green Features
ENRB 5-1 Green features & innovations 10 4.29
Category Score – Other Green Features 10 4.29
Category score for Other Green Requirements 37.42
Green Mark Score 90.56

GREEN BUILDING ASSESSMENT STANDARDS 5
The Green Mark Score of the building based on BCA Green Mark for Existing Non-
Residential Buildings (Version 3.0) is 90.56, as shown in Table 1 above. This is slightly above
the Green Mark Score of 90 needed for the building to be awarded with Green Mark Platinum
rating. Therefore based on overall Green Mark Score, the Green Mark Rating of the building is
Green Mark Platinum. However, it is important to note that the points located for different
categories of energy efficiency and other green requirements/features were based on the
scorecard points awarded to the building when it was analyzed under the BCA Green Mark for
New Non-Residential Building (Version NRB/4.1). There are some elements that were not
awarded any point because of insufficient information from the previous scorecard. This is
because there are some energy efficiency and other green building requirements included in the
BCA Green Mark for Existing Non-Residential Buildings (Version 3.0) but missing in the BCA
Green Mark for New Non-Residential Building (Version NRB/4.1), and vice versa. The elements
that did not have adequate information from the provided scorecard were not awarded any point.
The total points that were not awarded any point are 15. Thus if these points are excluded from
the total score, the Green Mark Score of the building is equivalent to 98.79. This overall score
rates the building as Green Mark Platinum. The total points from energy efficiency is 53.14,
which is more than the required minimum of 45 points hence the building meets the requirement
of Green Mark Platinum rating. Other requirements such as minimum efficiency of water-cooled
chilled-water plant and unitary air-conditioner or air cooled chilled-water plant systems, and the
percentage of natural ventilated areas facing North and South cannot be established from the
provided information.
As the owner plans to retrofit the building with an aim of ensuring it attains Green Mark
Platinum rating, he should focus on improving all areas that did not achieve maximum points

GREEN BUILDING ASSESSMENT STANDARDS 6
allocated and the new elements that were not originally included in the BCA Green Mark for
New Non-Residential Buildings (Version NRB/4.1).
Question 1(b)
From the scorecard of the building based on BCA Green Mark for New Non-Residential
Building (Version NRB/4.1), the total score of the building was 94.77, which exceeds the
minimum score of 90 that is needed for Green Mark Platinum rating. Nevertheless, the building
was awarded with Green Mark GoldPLUS and not Green Mark Platinum because of several
reasons. Two of these reasons are as follows:
The first reason is that since the building is air-conditioned, it was required to have a
minimum score of at least 5 points under NRB 3-1 Sustainable Construction for it to be awarded
Green mark Platinum (Building and Construction Authority, 2013). However, the building’s
score under NRB 3-1 Sustainable Construction was 3 and therefore it did not meet the
requirements for Green Mark Platinum rating.
The second reason is that since the building is air-conditioned, it was required to have a
minimum score of at least 4 points under NRB 3-2 Sustainable Products for it to be awarded
Green mark Platinum. However, the building’s score under NRB 3-2 Sustainable Products was 3
and therefore it did not meet the requirements for Green Mark Platinum rating.
Because of insufficient information available, it is not possible to establish if the building
met other requirements for Green Mark Platinum rating such as if at least 30% energy saving
was as a result of energy efficiency improvements and measures that were put in place to
decrease cooling load requirements of the building.
Question 1(c)

GREEN BUILDING ASSESSMENT STANDARDS 7
The pre-requisite requirements for a building to be awarded the Green Mark Platinum rating
as per the BCA Green Mark for Existing Non-Residential Buildings (Version 3.0) for a fully air-
conditioned of cooling load equal to or greater than 500 RT, using a water-cooled chilled water
system include the following:
i) Green Mark Score
For a building to get Green Mark Platinum award, it must have a total Green Mark Score of
90 and above. This score is the sum of scores allocated to energy efficiency, water efficiency,
sustainable operation and management, indoor environmental quality and other green features.
ii) Energy efficiency
The building should get a score of at least 45 points from part 1 – energy efficiency category.
The various elements under energy efficiency and their respective maximum points are as
provided in Table 2 below. This basically means that the building should have components,
systems, features, appliances, properties and practices that minimize energy consumption at
different stages of its lifecycle.
Table 2: Elements of energy efficiency
Energy Efficiency Maximum
points
ENRB 1-1 Thermal performance of building envelope 5
ENRB 1-2 Air conditioning system 32
ENRB 1-4 Artificial lighting 13
ENRB 1-5 Ventilation in car parks 4
ENRB 1-6 Ventilation in common area 5
ENRB 1-7 Lifts and escalators 2
ENRB 1-8 Energy efficient practices & features 12
ENRB 1-9 Energy policy & management 1
ENRB 1-10 Renewable energy 15
Total points 89

GREEN BUILDING ASSESSMENT STANDARDS 8
Therefore out of the 89 points, the building should attain at least 45 points for it to get Green
Mark Platinum award. This means that the owner has to improve each of the elements included
in Table 2 above to ensure that they consume as less energy as possible. Since the minimum
Green Mark Score for Green Mark Platinum award is 90, the other 45 points should be allocated
from the other elements of water efficiency, sustainable operation and management, indoor
environmental quality and other green features.
iii) Minimum efficiency of the water-cooled chilled-water system
Since the building is using a water-cooled chilled-water plant and its cooling load is ≥ 500 RT ,
the efficiency of the plant should be at least 0.65 kW/RT. This means that the owner has to
consider performance efficiency when selecting the water-cooled chilled-water plant.
iv) Measurement and verification (M&V) instrumentation of chiller plant
Permanent measuring instruments should be installed to monitor operating system efficiency
of the water-cooled chilled-water plant. The M&V instrumentation provided should be able to
calculate the resultant operating system efficiency of the plant in kW/RT within a percentage
difference of 5% with the actual value. The M&V instrumentation should also do the
calculations as per the guidelines provided in ASHRAE Guide 22 (ASHRAE, 2012) and AHRI
550/590 (AHRI, 2015). The accuracy of the M&V instrumentation should also be verified by
performing heat balance test on the water-cooled chilled-water plant.
v) Natural ventilation areas (only those that are occupied)
At least 75% of the occupied areas that are naturally ventilated should have effective cross
ventilation with their window opening facing South and North.

GREEN BUILDING ASSESSMENT STANDARDS 9
vi) Indoor air quality
A full indoor air quality audit should be conducted after every three years. The audit should
be carried out in accordance with the guidelines of NEA for good indoor air quality in office
premises. The audit can also be conducted in accordance with the indoor air quality for air-
conditioned buildings guidelines of SS554:2009 code of practice.
Works Cited
AHRI. (2015). AHRI Standard 550/590 (I-P). Arlington, VA: AHRI.
ASHRAE. (2012). ASHRAE GUIDELINE 22 Instrumentation for Monitoring Central Chilled-Water Plant
Efficiency . Atlanta, Georgia: ASHRAE.

GREEN BUILDING ASSESSMENT STANDARDS
10
Building and Construction Authority. (2013). BCA Green Mark for New Non-Residential Buildings Version
NRB/4.1. Singapore: Building and Construction Authority.
Building and Construction Authority. (2016). BCA Green Mark for Existing Non-Residential Buildings
Version 3.0. Singapore: Building and Construction Authority.
Building and Construction Authority. (2018, October 5). BCA Green Mark Assessment Criteria and Online
Application. Retrieved from Building and Construction Authority:
https://www.bca.gov.sg/GreenMark/green_mark_criteria.html