Phasing tools in Revit are used to control the graphic representation of 'time' in a project. In this use, they are also often abused. I've seen poorly managed phases in projects result in missing or duplicated information, as these tools can unexpectedly impact all modeled elements, including your view templates and schedules, etc. I will cover some of the benefits and issues of traditional phasing in future posts.
Phasing can also be used creatively to 'hide' template information that cannot be fully described in Revit legends. The power of Phases for creating reference information is the reason that I don't recommend using traditional Revit 'template' files (.rte file extension). I'll cover this in a future post.
To get started thinking about project phasing in Revit, about your project as a series of milestones along a timeline:
In this example, we're talking about a hypothetical project involving an existing occupied building. The scope of the project is a major addition to the existing building and a gut-reno of the existing building. From the builders perspective, this might look something like this:
- Project Start: site clearing, excavation, setting up hoarding, site servicing, etc.
- Phase 1: Major addition to the existing building such that the users of the existing facility have somewhere to move into, but can continue occupying their current space.
- Phase 2: Completion of addition. Major move of furniture and people into the new space. This might involve moving major IT equipment, etc.
- Phase 3: Demolition of interiors of existing portion of building which is now vacant. In this phase, the new addition is considered to be existing.
- Phase 4: Major interior renovation to existing portion of the facility.
- Project Completion: removal of hoarding, users moving back into the existing portion of the building.
If you've ever seen an actual construction schedule, you'll know that within these phases there are dozens of other phases describing all of the various trades and the critical path items required to complete the work.
I often see the project team try to represent the construction schedule using Phases in Revit. This is usually a mistake and can REALLY cost you in the long run. In Schematic Design and even through Design Development, it is often possible to keep several phases organized when precision is not the primary concern. When the construction drawings are in production, however, and more team members are working on the project, it will become extremely difficult to manage many project Phases. The added complexity will almost certainly lead to missing or duplicate information and lots of fun discussions with the client and builder during construction. I find that these issues tend to persist in the office because the people managing the project during design are not the same people who manage it during construction.
I would argue that the above-mentioned project should be phased in Revit using the out-of-the-box Phases that Revit provides: Existing & New Construction. Using phase filters you can appropriately show the demolition scope of work. Some argue that a "Temporary" phase should be established, but I would argue that this is only true where very complex construction phasing and hoarding is required, typically in occupied buildings. In the above mentioned project, you will likely only need hoarding to separate the new addition from the existing building once the interior retro-fit is underway. I recommend establishing hoarding assemblies as required (which should be included on your assemblies sheet anyway) - perhaps prefixing them with 'TEMP_xxxxxx" and using filters or worksets to hide them in views where they are not required to be shown. Depending on the requirements of your project, I find that diagrams with keynotes are a better way of illustrating project phasing.
If you have a very large project with very distinct phases of work, you may decide that it is worth separating the work into phases. I would argue that this may be important if you are producing renderings out of Revit directly (via VRay, Lumion, Enscape, etc) and you want to show the project as it will exist during various phases. Example:
1) South Tower is built in 2020
2) North Tower is built in 2021
3) Park / Site is completed in 2022
The major (often overlooked) risk to modeling phases into your project is the fact that it is typically not the design team's responsibility to establish how the project will be phased. That is tip-toeing into "telling the contractor how to build", which is a practice that may not be insurable if there is a dispute arising from how the project is phased.
- You want the Contract Documents to clearly indicate what is existing / proposed.
- You want to clearly represent how the building needs to be decanted, which spaces must be completed by which date or in which order the work must generally proceed, but HOW the contractor attacks the schedule constraints is their responsibility.
If the contract documents rigidly describe project phasing, it will be very difficult and potentially costly to change them if the contractor decides to proceed in a different way.
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