conventional design

Background
A conventional design process is not best suited for sustainable design because of the relative challenging nature of such projects which require more inter-disciplinary collaboration in addition to having intense performance requirements. The conventional design process for builds starts with a determination of the building’s core features, its architecture and layout by the client and architect. This is following by engaging various disciplines (civil, mechanical, electrical, etc). The work may be performed either in parallel or independently and in some instances both. The coordination of the design features from the various disciplines in a conventional design process is often by the project management as opposed to following a structured process.
The Integrated Design Process (IDP) is a modern design process that significantly improves on the conventional design as it entails a multi-disciplinary collaborative effort that engages the client and stakeholder throughout the process. There is continuous and active engagement of stakeholders as well as constructors and maintainers. This is crucial as the best buildings are products of consistent, active, and organized collaboration of all players. The IDP treats the building as a system across the whole building lifecycle. Thus, the IDP is modeled to better incorporate the activities required for building design along with minimizing liability on the part of the design firm.
The IDP has five primary sub functions, each having inputs and outputs. These are: 1. Acquire Design Project; 2. Plan and Control Design; 3. Acquire Resources & Services; 4. Perform Design; and 5.Communicate Design to Others. This model has such benefits as enabling the designer to view current and future steps in addition to providing a tool for defining project expectations. Also, IDP is a largely a collaborative process with active and continuous engagement of key players to ensure transparency resulting in building that optimizes the demands of the owner and occupants as well as performance of the building. Keeler (2009) describes the Integrated Design Process as sustainable or green design, while the DOE’s Greening Federal Facilities guide lauds it as the key to cost-effective green procurement strategy.
This paper outlines the following sustainable design and green building processes which are mapped to systems engineering process models: Requirements Gathering, First Charette, Sustainable Strategy, Systems Integration, Performance Criteria, LEED Criteria, Conceptual Design, Second Charette, Design Development, Schematic Design, Energy Modeling, Data Collection, Construction Documents, Construction, Commissioning, Acceptance, Real Time Commissioning and Occupant Survey. Also, End of Life is included though not mapped in the process models.
Requirements Gathering
Requirements Gathering entails determining of the requirements for the building in terms of mission, code, features, layout, flow and architecture. It is the determination and consensus on the requirements for the facility that lays ground for all further activities. The requirements are usually divided into mandatory items and desirable items.
Sustainable energy
All stakeholders must collaborate in determining the sustainable objectives of the buildings. Aspects taken into consideration at this stage include material selection, historic aspects, waste minimization, indoor air quality, and greenhouse gas emissions. These impacts on the site choice and influence the rating certification level to be achieved.
First Charette
A collaborative engagement in a workshop setting is necessary to determine the vision of the project. At this stage there is integration of project requirements and its sustainable strategy. There can be inclusion of the public as charrette participants.
Performance Criteria
Performance criteria is derived from the project requirements, and focuses on energy consumption for the building together with the incorporation of renewable energy sources. Also, there is inclusions of such design aspects as indoor air quality, material usage, etc. The performance criteria is designed to achieve the set level of green building certification.
Systems Integration
This stage entails integrating all the subsystems, components and aspects of the building so as to optimize performance of the building as a systems.
Conceptual Design
This phase sees the project team begin designing of the building with actual requirement and thorough consideration of details. Activities include building design modeling, identifying potential barriers, architecture planning, evaluation of detailed cost & performance goals, and listing of required building materials. At this stage, alternatives can be offered to the client.
LEED Criteria
Leadership in Energy and Environmental Design (LEED) is the US building certification standard that the project team could apply to the process models. This can be substituted with other green building certifications e.g. Green Globes and BREEAM.
Second Charette
A second charrette involving key stakeholders is held to ensure establishment of the performance criteria, that systems integration and conceptual design are in operation, and that key stakeholders are being engaged in a collaborative way in reviewing the progress and targeted outcome. Validation and verification occur at this stage when “building it right” and “building the right thing.”
Schematic Design
This phase entails translating of the conceptual design into graphical and written solutions which can be easily modeled and costed. This schematic design contains limited detail but provides sufficient details for analyzing alternatives, user concurrence as well as regulatory approvals.
Energy Modeling
This involves analysis of the building’s energy performance and its components using computer-based programs. To achieve the greatest impact, it is better to begin energy modeling at an early stage in the design process so as to influence the design and be advanced thereafter.
Design development
There is preparing of detailed design drawing, and specifications to include all disciplines (civil, structural, mechanical, electrical, fire protection, etc.).
Construction Documents
Construction documents include drawings, specifications, documents, contract terms, contract administration procedure, and bidding papers. This information is utilized for bidding and proposal purposes.
Construction
The building includes the site work and its utilities, which are erected and assembled.
Commissioning
Building commissioning is an important step that involves verifying that all subsystems function and perform in line with the design and specification. Also, there is validation of the performance of the building to meet the requirements of the owners/users.
Acceptance
This the last phase wherein the project team completes the high performance building to incorporate documentation, testing, verification & validation and handing the facility to the owner/user for occupancy.
Data collection
Ongoing data collection, measurement and reporting is needed to ensure continued high performance and energy efficiency of the building.
Real Time Commissioning
An ongoing methodology to analyze the performance of building and its subsystems and correcting any inefficiencies.
Occupant Survey
This is a post occupancy survey undertaken to evaluate the usability, air quality and comfort of the building.
End of Life
The entire building lifecycles considers such end of life decisions as retrofit for reuse, renovation, demolition and disposal. This process is not mapped to the process models.

Table below illustrates the sustainable design green building process of the project.

Project Requirements
Building Site and Program
The design challenge aimed to build a residential building for the client in New York City. The site for the building was located between a shopping mall (to the north-West) and a recreational park (to the south-East). The objective was for the residential building to fit within the aesthetics and layout of the existing context. The project was to produce a 3 story residential building.
Energy goals
The specifications of the project aimed to achieve “CasaClima A” certification, which is a regional energy certification whose evaluation tiers are founded on the project’s Space Heating Requirements (SHR). An A rating (the second highest) is achieved when it attains SHR of not more than 30kWh/m2y (9.5kBTU/ft2y). Projects that fulfill CasaClima Certification are referred to as “three-liter” projects because they need the equivalent of 3 liters of diesel fuel/square meter/year to meet thermal comfort requirements.
Design concept
The design concept of the project was to build a three-story residential house to fit in with the location’s aesthetic and make residents feel comfortable in an overly familiar space. The building has slopped roofs, small windows and primarily built of local stone and wood. Also, the two story eastern side would offer a splendid view of the urban neighborhood and to the public square.
In view of the basic concept, the conceptual energy analyses for the project were carried out to refine the building’s form and orientation.
Thermal Envelope Performance
The Project team adhered to the prescriptive envelope requirements by CasaClima. The wall assemblies had a cumulative thermal transmittance of not more than 0.8 W/m2K, and windows of U-value of between 1.4 W/m2K and 2.0 W/m2K.
Conclusions
The project was as success although it expressed such challenges as cold and windy climate, and a regional energy code which dictated most of the design decisions. The project team overcame these challenges by carefully studying the climate data to establish placement of the new building on the site.

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