🟩 What is a Basis of Design Document?.
During the Pre-Design Stage of the Commissioning Process, there is a requirement for a Basis of Design Document [BOD] to be written, issued, and developed by the Designer/Engineer of Record.
Sometimes when we request the document as the Commissioning Manager, we get stared at in a little shock and have many discussions with people, negotiating that ‘what was not done on previous projects is not an excuse. It needs to be completed on this project.
We try to explain what the document is, why it is needed and how to deliver it, taking up a lot of time for something that is a requirement of the Commissioning Process and most Green Building Certification.
In this article, we will run through the following:
- What is a BOD, and the definition of a Basis of Design Document?
- Where is the requirement for the document noted?
- Who is responsible
- How to write a Basis of Design Document
🟩 Basis of Design Document Definition
Written by the Designer, the Basis of Design Document [BOD] is written to provide all participants involved with the project a baseline, narrative, and overview of how the final design of the HVAC/Electrical/Plumbing and Fire equipment, systems, and integrations related to the project have been selected and designed against the Owners Project Requirements [OPR].
🟩 Where is the requirement for the document noted?
The requirement for the document to be created, managed, and issued is noted within:
- ASHRAE Guide 0-2019 The Commissioning Process &
- ASHRAE 1.1-2007 HVAC&R Technical Requirements for the Commissioning Process.
- LEED Green Building Council Fundamental/Enhanced Commissioning.
🟩 Who is responsible for the document
As noted below, various parties will need to be involved in producing a successful document, with differing responsibilities.
|Client||Review and comment on the BOD|
|Designer/Engineer of Record||Create/write and Manage BOD|
|Commissioning Manager [CxP]||Review, com|
Ultimately, the MEP Designer’s responsibility is to ensure the document is completed, reviewed, and accepted by the Client/Commissioning Manager.
🟩 How to Write a Basis of Design Document [BOD]
If you find that the Client does not have any specific requirements or this is the first time you are writing one, the BOD format can be based upon the ASHRAE requirements and developed if needed.
At this stage, the Owners Project Requirement document [OPR] should be written and accepted before the Basis of Design Document is started; if pushed, the OPR can be in a draft format as long as all parties agree that if there are any modifications, then the BOD will be updated immediately.
It is quite hard for a template to provide an exact format/example of the document, as projects and clients’ requirements will or can differ. Below is a list of what would be expected to be included, with a short explanation that can be used to get a start.
**Use the OPR, it will contain and provide a lot of helpful information to help.
🟩 Basis of Design Document Template / Format / Checklist:
The below checklist shows the general
|Intended usage of the building and spaces||Type of occupancy, how it affects the design and operation of the building. Unique challenges|
|System operation and maintenance expectations||How will the different systems operate? How it will be maintained, facilities staffing, etc|
|Design methods implemented||Method of Calculations for loadings, lighting, cooling, heating, people, u-values, etc. Software used or will use|
|Narrative of the design||For all systems and types, provide a general description, explain why it was selected, what equipment will be used, and integrate environmental systems. Types of materials to be used for the installations. Decentralized systems etc.|
|Narrative of the operation of the systems||Explain the intended operation of the systems Sequence of operations Time clocks Plant changeovers|
|Codes Guides Standards||To cover design, construction & commissioning of the HVAC / Building Services for the project.|
|Ambient Conditions||Outdoor Design Conditions Room / Space Conditions [temp, humidity, noise etc]|
|List performance criteria||Describe any specific design/performance criteria that have been stipulated by the OPR / Client Comfort Levels Air Quality Lux Levels Energy Requirements Specific maintenance requirements Ventilation rates|
|Sources of energy / fuel / supply||Explain the fuel sources that the building will utilize: Water Electric Solar Natural Gas Propane Diesel Oil Borehole|
|List of manufacturers||Provide a full list of the manufacturers that will be used on the project|
🟩 Basis of Design vs. Design Criteria
Some questions are usually asked about the difference between the Basis of Design Document and the document that details the Design Criteria.
The Basis of Design document includes information on the project and explains the systems, client expectations, and why the systems were selected and designed.
The Design Criteria usually only include a list of expected design information in tables that should be met.
Or see our article: 'OWNER’S PROJECT REQUIREMENT | [OPR] What is it'
🟩 BOD Meetings and Workshops
Throughout writing and having the document reviewed and approved, we should ensure regular meetings and workshops are conducted with all team members.
This will certainly help the process.
⬜ Basis of Design Free Checklist in Word [.doc]
To download an Open Copy of the basis of design checklist [word not excel], click the button below to be taken to our shop [payhip].