Building Information Modelling reaches its full potential when the structural, architectural, and MEP (Mechanical, Electrical, and Plumbing) models are coordinated in a shared digital environment. Clashes between a structural beam and a ventilation duct, or between a drainage run and a slab penetration, are among the most expensive problems in construction — and they are entirely preventable when all disciplines model their systems in Revit and coordinate in a federated model before construction begins. Revit MEP provides the dedicated tools for mechanical (HVAC and ventilation), electrical (power, lighting, fire alarm, data), and plumbing (hot and cold water, drainage) system modelling. This guide covers the core workflows for each discipline.
How Revit Handles MEP Systems
MEP systems in Revit are not simply geometric shapes — they are connected networks. A ductwork system is a tree of connected duct runs, fittings, and terminal units, all aware of the airflow, pressure, and velocity flowing through them. An electrical system is a network of circuits, loads, and distribution boards, tracking connected load and circuit protection requirements. This connectivity underpins the clash detection, system analysis, and documentation capabilities that make Revit MEP valuable beyond a simple 3D drawing tool.
Revit uses Connectors on MEP components to define how they link to systems. A fan coil unit, for example, has an air supply connector, an air return connector, hot water supply and return connectors, and an electrical power connector. When you connect ductwork to the air connectors and pipework to the water connectors, Revit understands the system topology and can report system performance data.
Mechanical: HVAC and Ventilation Systems
Placing Mechanical Equipment
Begin by placing the primary mechanical plant — air handling units (AHUs), fan coil units (FCUs), variable air volume (VAV) boxes, and exhaust fans. Load the appropriate Revit families from the MEP content library or from manufacturer BIM content portals. Place equipment at the correct levels and in the locations defined by the building services engineer’s design intent drawings.
Drawing Ductwork
Go to Systems > HVAC > Duct to access the duct routing tool. Before drawing, select the duct type (rectangular, round, or oval) and the duct system category (Supply Air, Return Air, or Exhaust Air). Set the duct size in the Properties Palette.
Draw duct runs by clicking from one point to the next. Revit automatically inserts elbows and tees as you change direction or branch the run. For complex routing, use the Auto-Route function: connect two equipment connectors, specify routing preferences (avoid conflicts with structure, prefer horizontal runs), and Revit calculates a path through the available space. Review and adjust the auto-routed run as needed.
Use Duct Fittings (tees, reducers, transitions, flexible duct connections) from the Systems tab to complete the ductwork configuration. Apply insulation to supply and return ducts using the Add Insulation tool.
Sizing Ductwork
Revit MEP includes a duct sizing tool that calculates duct dimensions based on design airflow rates, using equal friction or velocity methods. Go to Analyse > Reports & Schedules > Duct/Pipe Sizing. Input the design conditions — total supply air quantity, design velocity or pressure drop — and Revit calculates the correct duct sizes throughout the system, automatically resizing all runs to meet the specified criteria.
Electrical Systems
Placing Electrical Equipment and Devices
Electrical modelling in Revit covers lighting, power distribution, fire alarm, emergency lighting, and data/communications systems. Begin by placing distribution boards (consumer units, sub-distribution boards) at their correct locations. Then place electrical devices — socket outlets, light fittings, switches, data outlets — on walls and ceilings at the correct mounting heights.
Place lighting fixtures by going to Systems > Electrical > Lighting Fixture. Ceiling-mounted fixtures automatically host to the ceiling face. Wall-mounted fittings host to wall faces. Each fixture is assigned to an electrical system in the Properties Palette.
Creating Electrical Circuits
Circuits are created by selecting a group of devices and assigning them to a panel. Select a lighting fixture, then in the Ribbon go to Modify > Create Systems > Power. The Circuit Properties dialog appears — specify the panel, circuit number, breaker rating, and wire type. Repeat for all devices on that circuit.
Once circuits are defined, use Systems > Electrical > Wire to draw the circuit wiring. Revit offers logical wiring (schematic), chamfer wiring, and arc wiring styles. The wiring tool connects devices on the same circuit back to the panel, representing the electrical distribution graphically in the plan view.
Panel Schedules
Revit automatically generates panel schedules from the electrical model. Go to View > Create > Schedule/Quantities > Panel Schedule and select a distribution board. Revit produces a schedule showing all circuits, their loads, circuit breaker ratings, and the total connected and demand load on the board. This schedule updates automatically as circuits are added or modified.
Plumbing Systems
Placing Plumbing Fixtures
Plumbing fixtures — WCs, washbasins, showers, sinks, bath tubs — are loaded from the MEP content library and placed on the relevant level. Each fixture family includes hot water, cold water, and waste connectors.
Routing Pipework
Go to Systems > Plumbing & Piping > Pipe. Select the pipe type (copper, CPVC, steel, press-fit) and the system type (Hot Water Supply, Cold Water Supply, Sanitary Waste, Soil and Vent). Draw pipe runs from fixture connectors back to the building service entry points or risers.
Revit inserts fittings automatically as you route — elbows at direction changes, tees at branches. Use the Slope parameter for gravity drainage runs — UK building regulations require a minimum fall of 1:80 for branch waste pipes and 1:40 for single-appliance connections. Enable slope display in the 3D view to verify drainage falls visually.
Drainage and Soil Stacks
Model the soil and vent stack as a vertical pipe element, connected to each floor’s horizontal waste branches via junction fittings. Vent pipes branch from the stack at connection points and terminate above the roof at the correct height above any opening window — as specified in Part H of the Building Regulations.
Clash Detection with the Federated Model
The full benefit of multi-discipline Revit modelling is realised when the architectural, structural, and MEP models are federated for clash detection. Link all models together using Insert > Link Revit. Then export the federated model to Autodesk Navisworks via Add-Ins > External Tools > Navisworks. Run Clash Detective in Navisworks to identify hard clashes (physical intersections), soft clashes (clearance violations), and workflow clashes (scheduling conflicts). Each clash can be assigned for resolution and tracked through the coordination process.
Bringing Building Services to Life in BIM
Revit MEP transforms building services engineering from a 2D schematic discipline into a spatially coordinated, data-rich 3D workflow. The investment in MEP modelling pays off in reduced site coordination problems, faster documentation, and a more accurate information handover to facility management at project completion.
Revit 2026 is available from GetRenewedTech at €46.99 for one year of full access — including all MEP system modelling capabilities described in this guide.
