ASHRAE: From PreDesign to Construction Documentation

Written by Simon Whelan

November 22, 2019

Johnson Space Center NASA – Houston TX

Design Project Kick-off

The project kick-off meeting is crucial for establishing the Owners Project Requirements. This meeting allows the owner and stakeholders to define details and requirements for a successful project, including covering cover construction and operating costs, longevity, required spaces, functional aspects, specific maintenance or system preferences, frequency of use and other critical issues.  

Functional requirements would typically include the indoor environmental quality goals, thermal comfort for occupants, acoustic performance of the space, or lighting levels to support the necessary work tasks. It is strongly recommended that the OPR arising from the commissioning process includes the following information: targeted energy labels and/or energy ratings like Building eQ (ASHRAE 2011), Leadership in Energy and Environmental Design (LEED) (USGBC 2011), any constraints imposed by the site, code, or planning agreements with the city and pre-existing standards, if any.  

Concept Design

Concept design usually consists of a series of brainstorming sessions that allow the project team to review the OPR in the context of the site for any opportunities and risks. A key part of this stage is to investigate the site and look for shading or wind-shadows from adjacent buildings. Additional considerations at this stage are the availability of natural resources such as sun, hardscaping or landscaping, potential to reduce heat island effect or provide natural shading. 

In this stage, it is important to analyze all options on the façade orientation in the context of the site, consider energy solutions, shading, and occupants’ comfort.  

Some detailed considerations are: 

  • daylighting potential versus glare versus solar heat gain, glazing types, shading devices, and fenestration size, perimeter occupant comfort 
  • projected heat loss/heat gain and impact on annual HVAC energy use 
  • daylight harvesting and impact on potential energy savings
  • landscaping potential for natural shading 

Schematic Design

Within the schematic design phase, the project team further develops the design given the OPR’s requirements and the constraints on site. At this phase, the architectural team usually begins to identify the various occupancy options including leaving the center of the building for frequently unoccupied zones (conference rooms, copier rooms, storage areas, stairs, and restrooms) and high-heat-load areas (server rooms).This leads to the identification of façade locations where glazing would be desired to enhance the indoor environment for the occupants.  

 At this point, the prediction of solar path (specifically, profile angle) is recommended to assess the exposure of intended glazing locations and the resulting penetration of solar rays into the occupied perimeter zone. It is critical for the design team to re-check glazing areas and thermal performance against the ASHRAE/IES Standard 90.1 prescriptive requirements (ASHRAE 2010) or the recommendations for the relevant climate zone. This stage is critical because the team must avoid designs with sub-optimal glazing, either too heavily glazed or glazed below optimal performance levels. In addition, an in-depth analysis is required for the quantity and “frequency of occurrence” of natural resources like daylighting. Finally, in the schematic design phase, the design team identifies the energy conservation measures (ECMs). 

 When referring to passive performance parameters, it is important to consider: 

  • Selection of a façade type and orientation and each face’s relative proportion and performance of glazing and opaque wall insulation 
  • Selection of glazing visible transmittance (VT) versus solar heat gain coefficient to allow daylighting without overheating

Design Development

At the design development phase, designers apply the final ECM set onto the concrete architectural scheme while considering the building envelope and related regulations. Here, costs become a factor. If an ECM is removed or changed, the unintended consequences of this decision must be explored and analyzed. Consequences may include lowering the glazing VLT to reduce solar heat gain, eliminate daylighting as an ECM. This would require investigation of additional ECMs to meet the stated energy-saving goals 

Construction Documentation

The construction documents (CDs) phase is the final detailing of all systems, inclusive of sustainability features and ECMs.

About FenestraPro

FenestraPro is the leading façade design platform that supports the design and construction of beautiful, high-performing facades. Our integrated platform identifies and applies the optimal geometry, material selection, and fabrication information. The platform seamlessly integrates into BIM design and construction workflows while proven to:

  • eliminate the risk of late-stage redesign;
  • demonstrate local code compliance;
  • use data calculations in real-time;
  • integrate into BIM workflows.

Trusted by global leaders in green building design, FenestraPro enables designers to control overall thermal performances and aesthetic design to deliver sustainable, high-performing facades.


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