■ MEP BIM INSIGHTS — TOOLS & SOFTWARE

Revit Shared Parameters for MEP: What to Set Up Before Modeling Starts

Shared parameters are one of the most powerful features in Autodesk Revit — and one of the most commonly neglected at project kickoff. On MEP projects, getting them wrong means broken schedules, failed COBie exports, and parameters that exist in one model but not another.

Getting them right means every discipline tags, schedules, and exports data consistently — from the first model element to project closeout.

This article covers what shared parameters are, why MEP projects need them set up before modeling begins, and which parameters to define for a typical US commercial project.

What Shared Parameters Are — and How They Differ From Other Parameter Types

Revit has three types of parameters: family parameters, project parameters, and shared parameters. The distinction matters:

Family parameters — exist only within a specific family file. Cannot be scheduled across multiple families or tagged in views.
Project parameters — added to a project file only. Can be scheduled, but cannot be shared between project files or exported to IFC/COBie.
Shared parameters — defined in an external .txt file. Can be used across families and project files. Can be scheduled, tagged, and exported to IFC and COBie. The only parameter type that survives cross-project workflows.

For MEP BIM on US commercial projects, shared parameters are the only parameter type that supports tags, schedules, IFC export, and COBie simultaneously. Project parameters cannot do this. Family parameters cannot do this. Only shared parameters.

The Shared Parameter File

All shared parameters are defined in a single external text file — the shared parameter file (.txt). This file is the source of truth. Every Revit project and every family that uses these parameters must reference the same file.

The file is organized into groups. For MEP projects, typical groups include:

MEP — General
MEP — Mechanical
MEP — Electrical
MEP — Plumbing
MEP — Fire Protection
COBie

The file location should be on a shared server or CDE accessible to all project contributors. If every team member points to a different local copy, parameters diverge. This is the most common shared parameter failure mode.

Core MEP Parameters to Define Before Modeling

System and Classification Parameters

Parameter Name	Data Type	Used For
MEP_System_Classification	Text	HVAC, plumbing, fire protection system type
MEP_System_Abbreviation	Text	SA, RA, HW, CW, FP tags in drawings
MEP_Discipline	Text	Mechanical / Electrical / Plumbing / FP filter
MEP_Equipment_Tag	Text	Equipment ID in schedules and plans

Flow and Capacity Parameters

Parameter Name	Data Type	Used For
MEP_Flow_CFM	Number	Air volume for duct sizing and schedules
MEP_Flow_GPM	Number	Water flow for pipe sizing
MEP_Cooling_Capacity_Tons	Number	Equipment schedules, load verification
MEP_Heating_Capacity_MBH	Number	Heating equipment schedules
MEP_Electrical_KW	Number	Electrical load schedules

Physical and Installation Parameters

Parameter Name	Data Type	Used For
MEP_Insulation_Thickness	Length	Duct and pipe insulation in schedules
MEP_Insulation_Material	Text	Specification cross-reference
MEP_Mounting_Height_AFF	Length	Outlet and device installation height
MEP_Access_Required	Yes/No	Coordination flag for access panels

COBie Parameters

If the project requires a COBie deliverable — common on institutional, healthcare, and public projects — these parameters must be defined as shared parameters to export correctly:

Parameter Name	Data Type	COBie Field
COBie.Type.Manufacturer	Text	Type.Manufacturer
COBie.Type.ModelNumber	Text	Type.ModelNumber
COBie.Type.WarrantyDuration	Text	Type.WarrantyDurationLabor
COBie.Component.SerialNumber	Text	Component.SerialNumber
COBie.Component.InstallationDate	Text	Component.InstallationDate

When to Load Parameters — and Into What

Shared parameters need to be loaded in two places:

Into families

Open each MEP family (air handling unit, VAV box, pump, panel, etc.) and add the relevant shared parameters as family parameters. Parameters added here appear in the family’s instance or type properties and can be scheduled across all placed instances in the project.

Into the project file

Some parameters — particularly system-level and area-based parameters — are added directly to the project via Manage → Project Parameters. These apply to categories (ducts, pipes, conduit) rather than individual families.

The order matters: define parameters in the shared parameter file first, then load into families, then load into the project. Parameters added directly as project parameters cannot later be converted to shared parameters without breaking existing data.

Common Mistakes

Using project parameters instead of shared parameters — they cannot be tagged, exported to IFC, or used in COBie
Each discipline maintaining their own shared parameter file — results in duplicate GUIDs and broken cross-discipline schedules
Adding parameters after families are already placed — requires manually updating every placed instance
Not versioning the shared parameter file — parameter file changes mid-project break existing schedules
Naming parameters without a prefix convention — “Flow” and “System” clash with Revit built-in parameters; always use a project-specific prefix like MEP_ or GS_

Our Approach at GEOMETRY-S

We maintain a standard MEP shared parameter file that covers system classification, flow data, equipment data, and COBie fields for typical US commercial MEP scopes. At project kickoff, we review the BEP requirements and owner data requirements to confirm which parameters need to be active for that project.

If the project has a COBie requirement, we set up COBie parameters during family preparation — before a single piece of equipment is placed in the model. Retrofitting COBie parameters into a completed model takes significantly more time than setting them up at the start.

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