Spatial Separation Calculators

Spatial Separation Calculator 

The concept of spatial separation ensures that buildings are spaced far enough apart that fire is unlikely to spread from one building to another by thermal radiation. Both National Building Code of Canada, Ontario Building Code, Manitoba Building Code, British Columbia Building Code, and Alberta Building Code contain tables from which the percentage of unprotected openings that are permitted in a building or compartment are calculated. 


  • Exposing building face = 10 m x 3.5 m = 35 m
  • Limiting distance = 3.5 m
  • Occupancy = Group D

When read from Table the percentage of unprotected openings is between 30 m2 and 40 m2 on the vertical axis and between 3 m and 4 m on the horizontal axis as highlighted by the red box. The permitted percentage of unprotected openings is interpolated between the values as 57%. Therefore, up to 57% of the exposing building face is permitted to be unprotected. 

Spacial Seperation Caculators

The first calculator below shows the values from Tables and E for sprinklered Part 3 buildings. 

The second calculator below shows the values from Tables and C for non-sprinklered Part 3 buildings. 

Where the limiting distance or exposing building face area is between values on the respective table the calculator will interpolate between the values. Interpolation between the values is widely accepted by the Authority Having Jurisdiction. 

Simply enter the width, height, and limiting distance and the let the calculator do the rest.

Spatial Separation Calculator

Sprinklered Buildings

Spatial Separation Calculator

Non Sprinklered Buildings

* Persons preparing spatial separation calculations should review the applicable parts of the NBC, OBC, BCBC, ABC, or other  applicable code.  

** The calculator does not consider reductions in spatial separation where a building or compartment faces a street such as in NBC/OBC, open air parking garages, or low fuel load building under NBC/OBC/BCBC/ABC This calculator is designed to be an informational and educational tool only. 


Disclaimer and Copyright

The preparation of spatial separation calculations is the responsibility of the individual designer (architect, engineer, or other) that prepares the drawings/calculations. We strongly recommend engaging a code consultant such as Vortex Fire Consulting Inc. if you do not feel confident in preparing the calculations yourself.  The calculator provided is not intended in any way as engineering advice or services, or as a solicitation for any engineering product or service.  Any results from use of these calculators may not be applicable or accurate with regard to the individual circumstances, cannot be relied upon for anything, including, without limitation, engineering/architectural designs or decisions, and should not be the basis for any action or inaction on your part. 

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