Top 5 most useful BIM checks using Information Delivery Specification (IDS)

Introduction

The Information Delivery Specification (IDS) file is the machine-readable standard for defining BIM model requirements. It automates compliance checking for your IFC (Industry Foundation Classes) files, turning subjective contract clauses into clear pass/fail reports. The most common and valuable checks focus on the required data properties of key building components. Here's our 'non-definitive' top 5 most useful BIM checks.

1. Mandatory property set (Pset) and property presence

This is the cornerstone of all data requirements. A model is non-compliant if a required property set (Pset) or a specific property is missing from a key element.

What the IDS validates

• Existence of Pset: ensures entities like an IfcDoor, IfcWindow, or IfcColumn have the required standard property sets, such as Pset_DoorCommon or Pset_WallCommon.
• Existence of property: ensures a critical property exists within that set, for instance, checking for the FireRating or LoadBearing property.

Failure example

An IfcWall object is exported without the project's mandatory Pset_Construction, or an IfcDoor is missing the IsExternal property.

2. Constrained values and data types (the "correct answer" check)

Beyond simply existing, the data must be in the correct format and fall within an acceptable range or list. This reduces human error and ensures data is usable for downstream processes like FM or cost estimation.

What the IDS validates

• Allowed value lists: checks that a property value comes from a predefined list (an enumeration). For example, the OperationType for an IfcWindow must be "SingleSwing", "FixedWindow", etc.
• Data type compliance: ensures that a numerical property (like a thermal value) is exported as an IfcReal (a number), not as IfcText (a string).
• Minimum/maximum ranges: enforces dimensional or performance constraints, e.g., an OverallHeight must be greater than 2100 mm.

Failure example

The IfcDoor FireRating property is provided as "Unknown" when the IDS requires a specific minute value (e.g., "30" or "60").

3. Relationship and assignment properties (material and system metadata)

While IDS focuses on alphanumeric data rather than geometric relationships, it can validate that critical relationship information is documented through properties. This ensures that elements carry the metadata necessary for coordination, quantity take-offs, and facility management.

Note: IDS currently validates relationship information only when expressed as property values; direct IFC relationship validation is expected in future IDS releases.

What the IDS validates

• Material assignment properties: ensures elements have properties indicating their assigned materials (e.g., Material or StructuralMaterial properties are present and valid).
• System reference properties: checks that distribution elements (IfcDuct, IfcPipe) have properties referencing their system assignment (e.g., a SystemName property with values like "HVAC Supply Air System").
• Spatial reference properties: validates that elements include properties indicating their location context (e.g., StoreyName, ZoneName, or DepartmentName properties).
• Type and assembly references: ensures proper documentation of type relationships and assembly membership through property values.

Failure example

An IfcDuct is missing the mandatory SystemName property that would identify which HVAC system it belongs to, or an IfcWall lacks the required StoreyName property for facility management purposes.

4. Classification system compliance (e.g., Uniclass, Omniclass)

Standardised classification is necessary to categorise and filter information across different models and disciplines.

What the IDS validates

• Mandatory classification: enforces that an element must have an IfcClassificationReference assigned.
• Classification validity: ensures that the codes provided conform to a specific list or standard, such as checking that an IfcWall is using a valid Uniclass Ss (systems) or Pr (products) code.

Failure example

An IfcRoof is missing the mandatory Uniclass code required for handover documentation.

5. Correct IFC entity and predefined type usage

This check ensures model consistency by enforcing correct usage of the IFC schema, preventing geometric objects from being wrongly classified.

What the IDS validates

• Entity type: checks for the proper use of the main IFC entity (e.g., a door must be an IfcDoor).
• PredefinedType: ensures the object's subtype is correctly set. For example, an IfcWall might be required to have a PredefinedType of "STANDARD" or "PARTITION".

Failure example

A ceiling fan is modelled as a generic IfcBuildingElementProxy instead of the required IfcElectricAppliance entity.

IDS validation is critical for BIM projects - how do I check my IFC meets these requirements?

Automated IDS checking is a transformative step in the digital delivery process, moving from manual BIM model checks to automated, objective, and consistent validation of all IFC data. It directly addresses common issues that affect BIM coordination and data handover.

Use of an IFC IDS validation tool like Data Octopus can be a game-changer. In Data Octopus just follow these simple steps:

1. Upload your IFC and IDS files
2. Run a check
3. Examine the output of failed requirements on screen or via download
4. Optional - Use Data Octopus AI Fix to guide you through making the correct fix in your authoring software for the exact requirement specification