In the previous post we reviewed how to configure a code based key schedule. Now we'll review how that key schedule integrates with a room schedule to determine occupant load based on room area.
Why is it important that the occupancy calculations are integrated with room schedules rather than area schedules? Occupant load is based on the physical area a person can occupy within a room. Room area is defined to the face of bounding elements whereas Areas (defined with area plan) are typically inclusive of wall cavities, plenums, shafts and other building area incorporated in programming by gross-up factors. Occupancy based on Rooms rather than Areas is also important for analysis and determination of air changes and fire protection. Air changes and fire protection calculations are based on volumes of space. Rooms have volumes; Areas do not. It is also useful to define occupancy type and calculate occupant load based on Rooms rather than Areas when using room schedules as the basis for programming room data sheets. The last point to make for using Rooms rather than Areas to calculate occupancy has to do with exiting. I've yet to find a method to integrate occupant load to exit capacity (door width) and exit load (number of occupants divided by number of exits) but verifying this parametrically should be feasible in the near future or when I find someone who can figure out the boolean formula required for this! (And if you can figure that out I'd also like to make travel distance to exits parametric.)
So we have a defined occupancy key schedule based on the local building code. Next steps is defining the room schedule and assigning the occupancy classifications by room.
First step; define a room schedule from View - Schedules - Schedule/Quantities.
Add the fields required for the room schedule and create a Calculated Value field for the Occupant Load of the room
and a Parameter for Maximum Posted Occupant Load (for any areas where a maximum occupant load rather than a calculated occupant load will be used).
As rooms are added to the project the room schedule will populate. Assign the occupancy classification appropriate to the room usage as defined by the key schedule. The area per person value defined in the key schedule will be reflected in the area per person column and the occupant load will calculate based on the formula defined in the calculated value parameter. For occupant loads of zero define the occupancy classification as an area excluded from occupancy calcualtion (eg. corridors, washrooms, unoccupied service spaces, etc.). For areas with posted maximum occupant loads define the occupancy classification as a posted maximum occupancy and enter the posted occupant load value in the Maximum Posted Occupant Load column.
The total occupancy for the example schedule above would be the sum of the occupant load plus the sum of the posted max occupant - 583 people.
As room areas fluctuate the occupant loads increase and decrease accordingly affecting requried exit loads and capacities. These schedules can be introduced at any stage of BIM development however are best introduced earlier in the process as a design verification.
Why is it important that the occupancy calculations are integrated with room schedules rather than area schedules? Occupant load is based on the physical area a person can occupy within a room. Room area is defined to the face of bounding elements whereas Areas (defined with area plan) are typically inclusive of wall cavities, plenums, shafts and other building area incorporated in programming by gross-up factors. Occupancy based on Rooms rather than Areas is also important for analysis and determination of air changes and fire protection. Air changes and fire protection calculations are based on volumes of space. Rooms have volumes; Areas do not. It is also useful to define occupancy type and calculate occupant load based on Rooms rather than Areas when using room schedules as the basis for programming room data sheets. The last point to make for using Rooms rather than Areas to calculate occupancy has to do with exiting. I've yet to find a method to integrate occupant load to exit capacity (door width) and exit load (number of occupants divided by number of exits) but verifying this parametrically should be feasible in the near future or when I find someone who can figure out the boolean formula required for this! (And if you can figure that out I'd also like to make travel distance to exits parametric.)
So we have a defined occupancy key schedule based on the local building code. Next steps is defining the room schedule and assigning the occupancy classifications by room.
First step; define a room schedule from View - Schedules - Schedule/Quantities.
Add the fields required for the room schedule and create a Calculated Value field for the Occupant Load of the room
and a Parameter for Maximum Posted Occupant Load (for any areas where a maximum occupant load rather than a calculated occupant load will be used).
As rooms are added to the project the room schedule will populate. Assign the occupancy classification appropriate to the room usage as defined by the key schedule. The area per person value defined in the key schedule will be reflected in the area per person column and the occupant load will calculate based on the formula defined in the calculated value parameter. For occupant loads of zero define the occupancy classification as an area excluded from occupancy calcualtion (eg. corridors, washrooms, unoccupied service spaces, etc.). For areas with posted maximum occupant loads define the occupancy classification as a posted maximum occupancy and enter the posted occupant load value in the Maximum Posted Occupant Load column.
The total occupancy for the example schedule above would be the sum of the occupant load plus the sum of the posted max occupant - 583 people.
As room areas fluctuate the occupant loads increase and decrease accordingly affecting requried exit loads and capacities. These schedules can be introduced at any stage of BIM development however are best introduced earlier in the process as a design verification.
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