How to calculate occupancy with fixed seating?

[patricks]

We're using a schedule key and a schedule to help calculate occupancy loads and egress widths for our buildings. I copied the schedule and key from something posted on here a few years ago.

The question is - how can I get a number field that I can manually type in a number of fixed seats (like for church pews, counting 18" pew length per occupant), and have that added into the occupancy numbers?

I have tried adding a manual number Fixed Occupancy field, and then a calculated value that adds the Area Occupancy field and the Fixed Occupancy field together, so that I get a single column showing occupancy numbers for every room. The problem is that if there is nothing in either field, the formula breaks and nothing shows in that final calculated occupancy load field. If I try to add an occupancy type to my schedule key with 0 s.f. per occupant, then of course there is division by zero, and again nothing is shown in the Area Occupancy field, which means nothing is shown in the overall calculated occupancy field.

What I am trying to achieve is a single column showing the occupancy numbers for all rooms. I'd rather not have separate fields for rooms with or without fixed seats. Any ideas?

[saeborne]

I'm glad you asked this, because I am going to have to contend with a similar issue later. I think I found a working solution. It's a bit clunky, but it seems to work well. Take a look at the attached file.

In a nutshell, here's what I did:

1) I made a new parameter called Occ_Load_Fixed. I know... we don't want a separate parameter, but bear with me.

2) In the Occupancy Key Schedule, I noticed that Assembly with Fixed Seating is the only use group where the Load Factor equals Zero.

3) In the Room schedule, I updated the calculated value.

The forumla used to be.... Area / SF_per_person / 1' ^ 2,

Now, the formula is.... IF (SF_per_person>0, (Area / SF_per_person) / 1' ^ 2, Occ_Load_Fixed)

Which in effect says: "If the use group is not Assembly Fixed Seating, then divide Area by Load Factor. Otherwise, use the fixed load parameter."

4) In the room schedule, I hid the Occ_Load_Fixed column.

--

Potential pittfalls? If someone creates another key value equaled to zero, then we may have unintended consequences.

Let me know if this works for you.

Bryan

[patricks]

heyyyy now that sounds pretty slick! I didn't even think about using IF statements in my occupancy calculated values.

IBC codes and even SBC codes don't have any egress occupancies that would NOT be calculated by area other than assembly with fixed seating, so I don't see why anyone would add another schedule key with 0 for the area per occupant.

[thillhouse]

We take a slightly different approach. Some of aour occupancy parameters are project parameters which do not show up in our area tags. We therefore have a column that we manually have to type in the OL based on the calculated value, which helps in dbl checking the calculations, rounding etc... For fixed seating we just manually enter the number. We only do this because we have a tag that displays the area type, area, Occupancy Load, abreviation and Occupants.
I like the If then statement, and if Revit ever gets rid of the Project vs shared parameter then it would be great to have everything automated.

Tim

[mthurnauer]

What we did is that there is a parameter for Net/Actual Count. By default, the schedule uses a Net area calculation based on the Occupancy Type, but if Actual Count is checked, then the the schedule uses a occupancy number that is manually put in.

[saeborne]

What we did is that there is a parameter for Net/Actual Count. By default, the schedule uses a Net area calculation based on the Occupancy Type, but if Actual Count is checked, then the the schedule uses a occupancy number that is manually put in.

I like this idea. It's very straight forward for some of the... uh... less savvy users. The potential to over-ride any use group, with a fixed number is intriguing.

I do see a potential downside... This method definitely opens the door for someone to manually over-ride without knowing it. For example, a user could copy an area that is already set as Assembly / Fixed Seating. Then change the use group to Business, but forget to uncheck the "Net/Actual" parameter. Could easily result in an error, if one is not careful.

Bryan

[patricks]

I'm glad you asked this, because I am going to have to contend with a similar issue later. I think I found a working solution. It's a bit clunky, but it seems to work well. Take a look at the attached file.

In a nutshell, here's what I did:

1) I made a new parameter called Occ_Load_Fixed. I know... we don't want a separate parameter, but bear with me.

2) In the Occupancy Key Schedule, I noticed that Assembly with Fixed Seating is the only use group where the Load Factor equals Zero.

3) In the Room schedule, I updated the calculated value.

The forumla used to be.... Area / SF_per_person / 1' ^ 2,

Now, the formula is.... IF (SF_per_person>0, (Area / SF_per_person) / 1' ^ 2, Occ_Load_Fixed)

Which in effect says: "If the use group is not Assembly Fixed Seating, then divide Area by Load Factor. Otherwise, use the fixed load parameter."

4) In the room schedule, I hid the Occ_Load_Fixed column.

--

Potential pittfalls? If someone creates another key value equaled to zero, then we may have unintended consequences.

Let me know if this works for you.

Bryan

I finally got around to adding this into my current project, as well as into the template. Seems to work great. I hid the Occ Load Fixed column in the occupancy schedule, but I can still enter the fixed number of occupants in a room through that room's properties.

[saeborne]

Yeah... I'm going to add it to our Template as well. Cheers!

Bryan

[saeborne]

So the occupant load is a calculated value... per the formula listed above. Any idea how to display this in a Room Tag?

I realize that only Shared Parameters can be displayed in tags. Any good ideas on getting a calculated value into a Tag? I'd rather not type the number into a separate parameter.

[greg.mcdowell]

No way other than to type it into a seperate parameter. If you place the two parameters next to each other in the schedule it makes it easier to transfer the information. And, if the values are all numerical (as they are here) you can have the schedule total them so that you can, in theory, tell at a glance if you need to review the numbers. If the values are equal, odds are you're good to go.