Revit Families: An Effective Tool for MEP Engineers

Families – they are integral to just about everything in life. This is doubly true for Revit families in the world of MEP (mechanical, electrical and plumbing) engineering. The importance of Revit family creation, especially Revit MEP family creation, is paramount in Revit 3D modelling. So, what is Revit MEP family creation and how beneficial is it?

Since the Revit platform was created by Autodesk, perhaps the more relevant question is: What is Autodesk Revit MEP?

Revit MEP from Autodesk is a building information modelling (BIM) software created specifically for MEP engineers or other MEP professionals. The software enables modifications, additions and communication in intelligent models so that MEP systems, regardless of their complexity, can be precisely designed and documented in a relatively short time. An entire project can be represented as a single model created by Revit MEP and is typically stored in a single file. This way, any changes effected in one part of the model is automatically updated and modified in other parts of the model.

What are the key benefits of using Revit MEP?

Using Revit MEP within a BIM workflow increases productivity, streamlines design and documentation and speeds up project completion from the design stage to the construction stage while automatically updating changes across the model for every single change anywhere in the model. It does so with a range of tools and features designed to improve productivity, such as Building Performance Analysis, Autodesk 360 Integration, Construction Documentation, Pressure and Flow Calculations, Pressure Loss Reports, Parametric Components, etc.

Revit MEP also reduces risks and helps create high quality designs. It can be used to develop detailed BIM-ready product models with a high level of accuracy by an HVAC (heating, ventilation and air conditioning) manufacturing company, for example.

The engineering design process is streamlined with the use of a single model. The single model enables a more efficient communication of design intent before the start of construction. Building performance is improved this way, as project stakeholders can make more informed and precise decisions on design.

A thorough knowledge of creating ‘families’ and ‘types’ can positively influence the length of time it takes to create a model. Families consist of categories and sub-categories. Each category consists of individual families. For instance, consider the Sprinkler Category.

The category of Sprinkler can create several kinds of sprinklers. It is possible for families within this category to perform different functions and use different materials, which makes each of them a family ‘type’. Each family type has a graphical representation. When a specific family and individual family type is used to create a design component, it is known as an ‘instance’. Each instance has its own properties.

The parameters of an element can be changed without changing the parameters of the family type. Only the instance or element or component is affected by the change. When the parameters of the family type are changed, every instance of elements in the family type are changed.

The three main classifications of families are: system, loadable and in-place families.

System families are preinstalled families and create basic MEP elements, such as ducts and pipes. . System family settings include types for levels, grids and drawing sheets.

Loadable families are created elsewhere and then uploaded into the project. They are typically used to create MEP fixtures or other elements that be purchased, moved or fixed in and near a building. Revit MEP helps create and alter loadable families, as they are customisable. External RFA files are used to create them, and then they are loaded into the project. A loadable family with many types uses type catalogs to select a type of family. This family type can be identified and loaded into the project without loading all the family types. Specific kinds of loadable families are nested and shared families.

The third kind of families is the in-place family, which can be used to create customised elements. When a project requires a special individual element, in-place families are created with a specific geometry. The geometry of in-place families will then reference other project geometry and change itself based on the changes of the referenced geometry. Revit can create a family with a single-family type to create an in-place element.

During Revit MEP family creation, Revit 3D modelling can help analyse electrical systems, especially lighting, in a project, since a source of light has its own properties in a modelling setting. Nested families, which are families within other families, can be used to create families with multiple light sources. This is done using the host geometry of the main family. Various lighting fixtures can also be included.

Besides electrical components, Revit MEP family creation includes the creation of elements from other trades too. Some of the examples of Revit MEP family creation components, or elements, are as follows:

Revit Mechanical Family Creation

• HVAC components
• Pipes - valve, strainer and pipe hanger
• Duct hangers
• Air terminals

Revit Plumbing Family Creation

•          Pumps
•          Fixtures - urinals, wash basins, water closets
•          Valves
•          Devices - measuring devices, gauges
•          Fittings

Revit Electrical Family Creation

•          Transformers
•          Distribution boards
•          Switches and sockets
•          Fire alarm devices
•          Lighting fixtures

Revit HVAC Family Creation

•          Fan coil units
•          Air handling units
•          Fire dampers
•          Diffusers, grilles and registers
•          Fittings and valves

Revit Firefighting Family Creation

•          Sprinklers
•          Valves
•          Fittings
•          Fire extinguishers
•          Cabinets

Autodesk’s Revit is BIM software that includes MEP features and is commonly called Revit Bim, but Revit is not BIM. Revit has been created for BIM. The nice thing about BIM, well one of the nice things, is that the data that is stored in BIM throws up a few advantages for users of Revit Bim. Convenient scheduling, marketing that is exclusive, design changes that can be quickly communicated and implemented throughout a project and easy access for MEP designers are some of the advantages of using the information in BIM models.

It’s easy to see why Revit families and their creation are an effective tool for MEP engineers, but since sound technical knowledge is required to create object-based models in Revit Bim, many Western firms opt for offshore Revit modelling services when local talent is either challenging to find or too expensive to afford. Offshore modelling services developed with Revit family creation are increasingly found to be affordable, precise and delivered on time, making it the popular way to go.

Advantages of Revit Family Creation in BIM Technology

Similar to biological families, Revit families follow a certain order. For instance, a door is a ‘category’ of different components. There are different kinds of doors, and these different kinds of doors are different ‘families’. An example of a ‘family’ name would be a ‘flush door’. Within the family of the flush door, there are options for the flush door, based on dimension, material, etc. A flush door of a particular dimension is a ‘type’ of flush door. All the elements in a project’s design are created using families, including walls, roofs, doors, columns, beams, trusses, windows, fixtures, annotation, mechanical components, plumbing fixtures, lighting fixtures and other detailed components, and they can be created using Revit for BIM (Building Information Modelling) requirements in architectural design drafting.

Revit family modelling within the BIM context provides a range of advantages, namely:

• Improved layout plans
• Increased communication of plans
• Impressive Revit 3D modelling for marketing
• Detailed scheduling
• Customisation of projects

The creation of BIM models requires the extensive use of families. Walls, doors, windows, stairs, etc. may be of multiple types in the same project. A prime advantage of Revit families is that any change to a type will be updated in every instance of that type throughout the project design. For example, when the height of a window type is changed in one place, all windows of the same type will be modified instantly and automatically throughout the entire design.

The intelligent model-based process of BIM technology helps plan, design, construct and manage buildings and infrastructure and results in delivering specific outcomes with time and cost savings. Revit families and BIM content can be created for architectural, structural, mechanical, electrical and plumbing design. The process to deliver Revit families with high standards includes:
 

1. Selection of the family template
2. Planning the parameters
3. Creation of the model geometry
4. Assigning of the object subcategories according to requirements
5. Setting up visibility rules
6. Creation of family type

Revit allows created families of components to be stored and reused in other projects. They can be used as reference material by architectural designers to show prospective clients.

Builders, manufacturers, designers, engineers and other stakeholders in a project are dependent on model creation services for intelligent and parametric models that can host a complete group of components or equipment for BIM construction. Besides displaying the parameters of actual equipment and geometric components of windows, boilers, columns, etc. through graphics, Revit family modelling has other advantages, such as:

• Formula and imported data result in effective component design
• Regardless of size and design, the models created are accurate
• Resizing of models is both possible and economical
• Relationships and coordination between various elements of a unit are maintained
• Enabling building analysis and estimating

Revit modelling can create additional items like curtain wall panels, furniture, plumbing fixtures, electrical fixtures, machine parts, elevators and HVAC pumps. Family creation services include the following types:

• Structural
• Architectural
• MEP
• Building systems
• BIM
• Related custom and supporting content

Revit family creation, like real-life families, provides many benefits due to the inter-relationships they provide in a model. They are the driving force behind the success of BIM projects. With skilled Revit BIM practitioners available globally, accurate, cost-effective and viable project design services can be ensured.  

Why MEP Contractors Change MEP Design Models

In the MEP environment, a building’s MEP designs are initially developed at high level and then detailed to make them clash free and installation ready. MEP designers/consultants play a significant role in design decisions, construction planning, cost estimation and documentation. While design development is typically the role of the consultant and design detailing is done by the MEP contractor, when using MEP (M&E) BIM models and Revit BIM libraries, contractors invariably need to make changes to the MEP design model created by the consultant. 

To make a design installation ready, contractors may have to make several changes to the design-intent such as resizing of ducts, re-routing of pipework, adding wall penetrations, bolt locations and datum points for hangars and changing equipment. Once these changes are made by the contractor, the design would be installation ready and will need to be approved by the MEP consultant. The question that this article seeks to answer is why do MEP contractors need to make these and other changes to MEP design models?

• To adjust invert elevations – During the installation of plumbing or drainage pipes, MEP contractors deal with the point of the bottom inside of the pipe, this is known as the invert elevations. To guide pipe design and match the invert elevation height, elevation information can be vertically adjusted at the centre of the pipe using Revit. However, if you are unaware that the elevation information is in centre of the pipe, it could cause confusion in adjusting invert elevations and create discrepancies while coordinating with other disciplines. This is the reason why MEP contractors need to manually adjust invert levels, create spot elevations for the inside bottom of the pipe and change the design models to install pipes which are coordinated with other disciplines. 
• To retrofit MEP systems into a prefabricated module environment – Planning for prefabrication of MEP components into the 3D model would not be considered by designers and therefore the contractor is the party who will make adjustments to services to allow them to fit into prefabricated modules to maximise the advantages that are gained from off-site fabrication. In several MEP projects which require prefabrication of risers, ceilings and plant room areas, MEP services drawings and modules specifically for fabricators and installers is necessary to facilitate proper installation. MEP contractors make changes in the MEP design model to ensure that services fit within modules within the ceiling or riser space to allow prefabrication of MEP components off-site allowing faster installation on-site.
• To facilitate efficient spatial coordination – When installing MEP systems, effective spatial coordination with other building services and disciplines is imperative. A consultant may leave clashes in a model as his focus will be on getting a design issue by a due date. A contractor is more concerned with actual fitting so after conducting a clash test on the 3d model, MEP contractors will invariably change design models to ensure that all services are not clashing. The installation programme of the MEP system depends on clash free layouts and MEP contractors must make sure that MEP systems are spatially coordinated with other disciplines in the 3D model before creating M&E (MEP) Coordinated Drawings.
• To deal with constructability issues – There are several factors that influence the constructability or sequence in which MEP systems are installed. Some of the conflicts that require a change in MEP design include routing, fitting and sequencing of large equipment within a given space, conflicting piping network and installation of MEP systems within a crowded space. As MEP contractors need to tackle several conflicts and constructability issues before installing MEP systems, a change in MEP design usually occurs. 
• To install MEP systems economically and efficiently – While the MEP design intent may seem to be perfectly coordinated, it need not necessarily be economic or efficient when it involves installation. There are several costs involved when changes need to be made after installation such as re-routing pipes to reduce bends, re-positioning ducts to allow supply and extract in the correct locations, changing equipment or adding wall penetrations, bolt locations and datum points for hangars. To make sure that MEP systems are installed economically and efficiently, MEP contractors must make changes to MEP design models.
• Changes in materials and components – In some cases the MEP model from a consultant is accurately modelled with specified parts, materials and components. However, in some cases projects do not have specified parts and a consultant may use library elements from Revit leaving the contractor to update the model using his planned procurement schedule. This will result in changes due to sizes and access requirements for new components such as a change from copper to plastic pipe which is thicker or a change from one set of pumps to another that may be larger and may have different valve arrangements. The knock-on effect of such component changes can mean that other systems also need to be changed. 

Given the many reasons why MEP contractors need to change MEP designs and with the adoption of MEP (M&E) BIM practices, there is an overlap in the scope of MEP contractors and consultants during the planning phase. To know more about how you can reduce the duplication of efforts, additional costs, manage project schedules and reduce scope overlap, read more in this post to find out the possible routes that can be taken.

To ensure MEP design models are installation ready for MEP contractors to use on site, a viable solution would be to work with a 3D BIM coordination specialist or MEP engineering design service provider. At XS CAD, our experienced team of MEP designers in India provide BIM support and spatially coordinated building services drawings for key stakeholders in the MEP (M&E) industry, from MEP (M&E) consulting engineers and MEP (M&E) building services contractors. In our spatially coordinated MEP building services models, we use the latest 3D MEP (M&E) modelling software (Revit MEP) and clash detection technology (Autodesk Navisworks) to provide 3D M&E (MEP) coordinated drawings which adhere to engineering standards, the structural and architectural elements within a building.