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The Level of Information Need (LOIN), describes which information about a building or component is required for a specific purpose, at a specific point in time and at a defined level of quality. Geometric information, alphanumeric information and documentation are considered separately.
The aim is not to make a BIM model as detailed as possible, but to provide exactly the scope of information required for the relevant use case.
Why is the Level of Information Need important?
- Fit-for-purpose models: Only the information that is actually needed is created and maintained.
- Less modelling effort: Unnecessary geometric details or attributes are avoided.
- Clear requirements: Clients and contractors can clearly define which information is required and when.
- Better data quality: Information requirements can be checked systematically and traced.
- Efficient BIM processes: Models are developed to support design, construction, refurbishment or building operation.
What information does LOIN cover?
The Level of Information Need distinguishes between three core types of information.
Geometric information
This describes the spatial representation of an object.
Examples include:
- Shape
- Dimensions
- Position and orientation
- Dimensionality
- Geometric detail
- Relationships with other components
The geometric detail required for a component depends on the relevant use case.
Alphanumeric information
This comprises the structured properties and characteristics of an object.
Examples:
- Material
- Component type
- Fire resistance class
- U-value
- Manufacturer
- Costs
- Technical performance data
- Maintenance information
The same principle applies here: not every attribute is required at every project stage.
Documentary information
Documents may also form part of the information need.
Examples include:
- Product data sheets
- Test reports
- Certificates
- Supporting documentation
- Installation instructions
- Maintenance documents
- Manufacturer documentation
The required scope of geometry, alphanumeric information and documentation may differ in each case.
How is the Level of Information Need defined?
1. Determine the intended use
First, it must be clear what the information is needed for.
Examples:
- Existing building survey
- Design
- Clash detection
- Quantity take-off
- Energy calculations
- Tendering
- Construction
- Building operation
2. Define the information delivery point
Requirements can change over the course of a project. A concept design requires different information from detailed design or as-built documentation.
3. Identify the information users
The stakeholders involved also influence the information need.
Architects, MEP planners, energy consultants and facility managers may require different information about the same component.
4. Define the required objects
The next step is to specify the rooms, components or technical systems for which information is required.
5. Define the scope of information
For each relevant object, the geometric, alphanumeric and documentary information that is actually required is defined.
This creates a purpose-driven information need instead of a blanket level of detail.
Example: LOIN for a window
The information required for a window depends on the use case.
For early-stage area planning
The following information may be required:
- Position
- Approximate width and height
Manufacturer data or maintenance information is generally not required at this stage.
For an energy assessment
The following may be relevant:
- Exact dimensions
- Frame proportion
- Glazing
- U-value
- Orientation
For building operation
Additional information may be required:
- Manufacturer
- Product type
- Serial number
- Maintenance information
- Technical documentation
The component remains the same, but the information need changes with its intended use.
LOIN in existing building modelling and scan-to-BIM
In existing building projects, the Level of Information Need already determines which building data must be captured and how it must subsequently be modelled.
The following should therefore be clarified before a digital building survey:
- Which areas of the building are required?
- Which components need to be modelled?
- What level of geometric accuracy is required?
- Which attributes are needed?
- Which documents must be linked?
- Which information will later be used in BIM, CAFM or energy consulting?
For a simple as-built floor plan, for example, detailed modelling of technical systems is not required.
If the model is to be used for a heating load calculation, energy-efficient refurbishment or building operation, additional information about the building envelope, rooms or MEP systems may be necessary.
One possible workflow is:
Use case → LOIN → digital building survey → point cloud → Scan-to-BIM → IFC model → further use
This avoids the time-consuming capture or modelling of data that ultimately provides no specific benefit.
LOIN vs. LOD
Level of Detail or Level of Development (LOD) and Level of Information Need (LOIN) are often confused.
LOIN replaces the rigid, traditional and non-standardized LOD concept (Level of Detail) and is governed by DIN EN ISO 7817-1. Instead of general stages such as LOD 100 to 500, LOIN follows a pull logic: information is requested precisely according to the actual project need.
LOD
- Often works with defined levels of development or detail
- Combines different aspects of geometry and information depending on the system used
- Continues to be used in BIM practice
LOIN
- Is based on the specific information need
- Considers geometry, alphanumeric information and documentation separately
- Takes account of purpose, timing and the stakeholders involved
- Avoids blanket requirements for ever-higher levels of modelling detail
LOIN therefore does not simply mean “more detail at a higher level”. The decisive question is whether information is required for the specific use case.
Are there LOIN 100, 200, 300, 400 and 500 levels?
Terms such as LOIN 100 to LOIN 500 can be found in some guidelines and project specifications. However, they should not be confused with a universally applicable level system under the current DIN EN ISO 7817-1.
The current standard takes a more differentiated approach: the information need is described according to the purpose, information delivery point, stakeholders and objects, together with the geometric, alphanumeric and documentary information required in each case.
Project-specific levels may be used for simplification, but the decisive factor is what is specifically required within such a level.
LOIN and Exchange Information Requirements (EIR)
LOIN plays an important role within the Exchange Information Requirements.
The EIR define which information a client requires for specific BIM use cases and project stages.
LOIN specifies this information need in more detail, for example for individual:
- Components
- Rooms
- Discipline models
- Systems
- Information deliveries
This makes it possible to formulate requirements much more precisely than with general statements such as “a model with a high level of detail”.
LOIN and the BIM Execution Plan (BEP)
While the AIA define the required information need, the BIM execution plan, describes how these requirements are implemented in the project.
A BAP can define, for example:
- Who creates the required information
- When models are delivered
- Which exchange formats apply
- How information is checked
- How information is reviewed and coordinated on a BIM collaboration platform
- How the agreed information requirements are implemented and monitored
In this way, LOIN connects technical requirements with operational BIM processes.
Current standard
The current standard for the concept is DIN EN ISO 7817-1:2024-11, “Building information modelling — Level of information need — Part 1: Concepts and principles”.
It replaces the previous DIN EN 17412-1:2021-06.
DIN EN ISO 7817-1 describes a methodological framework for defining the information need and covers the entire life cycle of a building, from design and construction to operation, modernization and end of life.
Common mistakes and misconceptions
- Treating LOIN as a blanket level of detail: The information need covers more than geometric detail.
- “The higher, the better”: More data does not automatically result in better models.
- Requesting all information at the same time: Information requirements should match the relevant project stage.
- Failing to distinguish geometry and attributes: A component may require simple geometry but extensive alphanumeric information, or vice versa.
- Not defining the use case: Without a specific purpose, it is difficult to determine a meaningful scope of information.
- Defining LOIN only after modelling: The information need should ideally be known before data capture and model creation.
- Referencing an outdated standard: DIN EN 17412-1 has been replaced by DIN EN ISO 7817-1.
FAQ
Who defines LOIN?
Information requirements are derived primarily from the needs of the client and the relevant information users. In BIM projects, they are specified in documents such as the AIA and implemented through the BAP.
Which standard applies to LOIN?
The current German standard is DIN EN ISO 7817-1:2024-11. It replaces the previous DIN EN 17412-1:2021-06.