Modelling Insulation on Mechanical Components
Most MEP models that we receive are modelled without insulation for ducts and pipes.
I'm not quite sure for the reasoning behind this. Although, if pushed to provide a reason, I would suggest that it's not normally modelled due to the additional work involved.
The effective routing of pipes and ductwork is an important part of any facility. Ideally, all mechanical and electrical services need to be located in the minimum about of required space, whilst ensuring that sufficient and safe access can be provided for inspection and maintenance. This should mean that all service routes are safe and efficient.
For all spaces and the components within spaces to be fully coordinated, all physical items should be modelled. To be clear this doesn't require a high level of detail for all the physical components, but it does require that the full physical extent of a component is modelled. For ductwork, this would include any required insulation. As the insulation increases the physical dimensions of the duct.
Duct and Pipe Insulation Within IFC
IFC expressly allows for insulation to mechanical components such as ducts and pipes.
- IfcCoveringType for duct product types
- IfcCoveringType for pipe product types
This adds additional weight to the inclusion of insulation within MEP models.
Unidentified Insulation Clashes
One of the primary purposes of BIM is to resolve design and construction issues during the design process, preventing costly site rework.
If insulation is not modelled, potential coordination clashes may not be identified and resolved during the design process.
In the following example, the duct does not directly clash with the ceiling grid. Ignore the fire damper which does clash, although the fire damper itself is not correctly located. It should be located within the line of the partition wall.
If insulation is added to the duct then the insulation will clash with the suspended ceiling grid.
The potential clash could be identified in a couple of ways:
- Clearance Test, setup a rule to allow for required clearance to all ducts
- Model Insulation, insulation is provided by default to all ducts requiring insulation
Either method could provide satisfactory results. However, as the depth of insulation may vary for each component and as some components may not require insulation, using a clearance rule could quickly become very complicated. Such complications could produce false positives, where an issue is generated that in reality does not cause a problem. False positives waste time and make it difficult to separate the real issues from the non-issues.
Provide a fully coordinated design should be a target of all projects.
An argument for not modelling insulation is that it obscures the detail of the ducts. You can't easily see the ducts when they are covered by insulation.
It's true that this could be a problem. Although, only a problem if a model is viewed as a single entity that cannot be manipulated.
The insulation can be contained within a different volume, essentially, a different MEP model. The insulation volume can be combined together with the other MEP volumes, to view the full MEP system and to check for clashes. But, when insulation obscures information and design detail the model can be viewed without the insulation volume.
A quality, fully coordinated model requires insulation to be modelled