# Are there rules for Custom Pset naming conventions?

**URL:** <https://forums.buildingsmart.org/t/are-there-rules-for-custom-pset-naming-conventions/4984>\
**Category:** Software Certification\
**Created:** [October 23, 2023, 10:45am UTC](https://forums.buildingsmart.org/t/are-there-rules-for-custom-pset-naming-conventions/4984 "2023-10-23T10:45:28Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![AntonioCWD](https://avatars.discourse-cdn.com/v4/letter/a/958977/32.png) [@AntonioCWD](https://forums.buildingsmart.org/u/AntonioCWD)\
**Post date:** [October 23, 2023, 10:45am UTC](https://forums.buildingsmart.org/t/are-there-rules-for-custom-pset-naming-conventions/4984/1 "2023-10-23T10:45:28Z")

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Are there rules for authoring applications when it comes to naming custom Property Sets (psets)? For example, is there a rule that states, “Custom pset names cannot start with ‘Qto\_’ because this is reserved for buildingSMART psets only”?

If such rules exist, where can I find them?

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**Author:** ![jwouellette](https://sea2.discourse-cdn.com/flex016/user_avatar/forums.buildingsmart.org/jwouellette/32/2140_2.png) [@jwouellette](https://forums.buildingsmart.org/u/jwouellette)\
**Post date:** [October 23, 2023, 7:52pm UTC](https://forums.buildingsmart.org/t/are-there-rules-for-custom-pset-naming-conventions/4984/2 "2023-10-23T19:52:42Z")

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Currently, the primary rule is that any custom Pset CANNOT be simply named “Pset\_xxxxx”. The prefix must be something, anything, else and may be an identifying name like:

AASHTOBridgePset\_…  
CustomPropertySetbSUSA\_…  
MyCompanyMyProductPropSet\_…

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<div class="post-metadata">

**Author:** ![AntonioCWD](https://avatars.discourse-cdn.com/v4/letter/a/958977/32.png) [@AntonioCWD](https://forums.buildingsmart.org/u/AntonioCWD)\
**Post date:** [October 24, 2023, 6:04am UTC](https://forums.buildingsmart.org/t/are-there-rules-for-custom-pset-naming-conventions/4984/3 "2023-10-24T06:04:42Z")

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Thank you kindly for the quick reply.  
Is there a source you could link or point me to?

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<div class="post-metadata">

**Author:** ![jwouellette](https://sea2.discourse-cdn.com/flex016/user_avatar/forums.buildingsmart.org/jwouellette/32/2140_2.png) [@jwouellette](https://forums.buildingsmart.org/u/jwouellette)\
**Post date:** [October 24, 2023, 1:10pm UTC](https://forums.buildingsmart.org/t/are-there-rules-for-custom-pset-naming-conventions/4984/4 "2023-10-24T13:10:05Z")

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It is in the definition of IfcPropertySet itself:  
[5.1.3.14 IfcPropertySet - IFC4.3.2.0 Documentation (buildingsmart.org)](https://ifc43-docs.standards.buildingsmart.org/IFC/RELEASE/IFC4x3/HTML/lexical/IfcPropertySet.htm)