Building Types & Occupant Loads

I still haven't decided whether my Blog will cater specifically to Building Design/Construction or personal stuff. For the most part, I think it will have a lot of design related issues. I'll throw in a joke in every once in awhile...I promise.

One of my pet peeves of late has to do with Building Occupancies and Occupant Loads, and to some extent, Building Codes in general. Primarily because of a recent design experience with an Assembly Space, and  recent modifications in occupancy loads. I think all Churches and  other places of Assembly should be fully sprinkler-ed.  I think building owners should have an incentive to include adequate fire-suppression systems, especially in places that are open to the general public.  I think classrooms, conference rooms and cafeterias should not exceed their maximum occupant loads (at all times). I always remind my clients that Building Codes are the MINIMUM Requirements that are implemented by the local Authorities having Jurisdiction, and sometimes, some things don't always get implemented at all!  Just look at Chapter 1- Administration of IBC 2006 (International Building Codes as adopted by the State of GA).  

Reference: 101.3 Intent - The purpose of this code is to establish the minimum requirements to safeguard against public health, safety and general welfare through structural strength, means of egress facilities, stability, sanitation, adequate light and ventilation, energy conservation, and safety to life and property from fire and other hazards attributed to the built environment and to provide safety to fire fighters and emergency responders during emergency operations.

That's a lot to take in, right?  This is why most Architects are unwilling to sign and seal your napkin sketch so that you can get a building permit.  (Let's not forget the close relative, who knows a  little about construction, and offers to build that addition for free!!). That may be true, but please do the right thing.

Hire a qualified GC/Remodeler like Mark Galey- (www.magnetconstruction.com).

I have this habit of doing a quick sweep of every building or space that I enter to make sure I know where the exits are, where the nearest fire extinguisher is located, where the stairwell is located and if the building is fully sprinkler-ed. Then, I start picking out all the bad details that could have been better, critique the finishes and all the areas where poor workmanship/execution is obvious. I know, it's a terrible thing to do but I bet every other professional who is directly connected with public safety and welfare go through the same analysis as they enter a building. Just for the record, I also take note of the good details and learn from them.

Remind me to tell you about one of our clients who simply refused to add a sprinkler system to the building (Assembly Type 3) and ended up dividing the building into two separate structures just  to accomplish that goal- In the year 2010 is this socially irresponsible or just plain short-sightedness? We proved that they really didn't save any money with that decision based on all of the additional cost impacts relating to additional foundations, exterior walls, structure, duplication of services, separate toilets, mechanical systems, etc. etc.

That brings me to the other area of the Code that deals with Occupant Loads with a focus on Public Buildings, Churches and School Facilities. This is where the Life Safety Code NFPA 101 (National Fire Protection Association) takes over as the Agency having Jurisdiction over the Building Department. Just as a guide, here are a few Occupancy Loads that are issued in accordance with NFPA 101. You can make your own determinations and see how they affect the spaces you occupy on a daily basis. The maximum occupancy for a room can be determined by using the formula (area/sf per person = occupancy load).

Gross SF vs Net SF.

Gross SF = Unit of measurement of a building from outside the exterior walls.

Net SF = Unit of measure inside a room or space, minus all built-in furniture and appliances.Thickness of walls is not included in this area calculation.

Assembly Spaces (Churches, Cafeterias, Conference Rooms) -

Concentrated uses with fixed seating               7 net SF/Person

Less concentrated use, w/o fixed seating        15 net SF/Person

Bench Type Seating                                       1 person per 18 linear inches

Educational Use 

Classrooms                                                   20 net SF/Person

Business Use                                               100 SF/Person

Sales area on street floor                               30 SF/Person

So, I guess what I'm trying to say is that there is a  lot of background "stuff" that goes on before "blueprints" are even generated. Architects, Engineers and other Design Professionals are always striving to create better solutions, by setting our standards a bit higher than the ones set by  the Authorities. Just call us wild and crazy, because sometimes, just sometimes, what we design might end up staying up longer than expected.