Technical Clarification

Clarification of extent of blinds/fixed shading required

Technical Clarification Number


The GBCSA confirm that: 

  • 100% of the windows within the Usable Area (UA) requires fixed shading when following this route to compliance. Windows that do not fall within the UA do not require fixed shading.
  • 100% of the windows within the Usable Area (UA) requires blinds when following this route to compliance. Windows that do not fall within the UA do not require blinds.


Technical Clarification
Solid opaque blinds
Technical Clarification Number

(replaces IEQ5-T-OB1-612)

The GBCSA confirm that for the purposes of proving compliance with the IEQ-5 Daylight Glare Control credit, solid (not perforated or woven) opaque blinds such as solid metallic or solid timber blinds can be assumed to have a VLT of < 10%. Confirmation from the manufacturer or manufacturers datasheets detailing the nature of the material component must be provided in the submission however and this assumption clearly stated referencing this Technical Clarification.

Similarly, in most instances ‘block-out’ fabric blinds will also have a VLT < 10%. Where the VLT of the block-out fabric product is unknown, project teams may provide documentation from the supplier merely showing that the fabric is being marketed as “block-out” fabric and no VLT information is required.




Credit Interpretation Request

Manual override of automated blinds with a monitoring system may be omitted

Credit Interpretation Request Number


The GBCSA confirm that: 

Manual override of automated blinds with a monitoring system may be omitted on the basis that the project team demonstrates that the automation and monitoring system in combination with the particular blind design can meet the aim of the credit without intervention from occupants.

It would be expected that the system is able to keep direct sunlight off occupants in the designated UA during daylight hours via the physical design of the blinds, and that the automation as well as the monitoring system ensure that the blinds are operating as intended (are in the correct position per the time of day and or year.) If the system does allow direct sunlight to pass into the occupied area for any design reasons (e.g. directing solar gain onto the ceiling in winter to reduce space heating) it should be demonstrated that the system can be adapted to future tenants, adjustment in furniture layouts to ensure the glare control requirements can still be met. It is to be noted that the blinds still need to meet the current glare control requirements expected of manual control blinds with regards to transmission of materials and the amount of light passing between framing and the blinds.

Documentation Requirements:

Short Report - The short report must detail the nature of the blind system, including the physical blinds as well as the automation and the monitoring system referencing relevant contractual project documentation. It must be demonstrated that 95% of all direct sun penetration will be  avoided without intervention from occupants.

Extracts from Specifications (Design Rating) - Contract documentation must clearly indicate the inclusion of the automation and monitoring system as described in the Short Report.

Extracts from Commissioning Report (As Built Rating) - confirming that the blind system including automation and monitoring has been commissioned and is operating as intended by the design.

Extracts from the O&M manuals (As Built Rating) - indicating how the system would need to be reprogrammed to adjust to new conditions if and when required.



Technical Clarification

Manual blinds

Technical Clarification Number


In addition to the Credit Criteria stated in the technical manual, the following additional credit criteria have been developed. Projects using the following criteria can claim one point for this credit. This criteria can be used in conjunction with the criteria stated in the technical manual, or by itself.

One point is awarded where it is demonstrated that glare from daylight is reduced through the fitting of blinds or screens on all glazing and atria as a base building provision and meet the following criteria:
- Eliminate 95% of all direct sun penetration; AND
- Have a visual light transmittance (VLT) of ≤10%; AND
- Can be controlled by all affected occupants within each floor or area.

Projects seeking to claim this alternative methodology must use the documentation requirements for Occupant Controlled, Automated Blinds/Screens as stated in the credit criteria, with the exception of the provision of an automated motorized control for these blinds.

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