(Building) Code Assessment Drawing on the Experience of Others Barry D. Yatt, FAIA, CSI Arch 402/503 School of Architecture and Planning The Catholic University of America
Why? • In poorly designed buildings, people can get hurt. • People want assurance that the buildings they live in meet a minimum standard of quality. • Architects sometimes need a little help designing safe buildings. (Nobody is born with the knowledge and schools don’t provide enough exposure.)
Approach • Codes let designers decide what functionality and overall form they want. • Designers let codes set minimum performance levels to increase the chances that the design will be safe.
How? It's all about if/then relationships. • If you decide x… …then the code will require y. • If you don’t like y… …then you can change decision x.
What? • Configuration (bldg size, compartmentation) • Fire-resistance (how long it lasts) • Egress (occupant count, path to safety) • Habitability (size, comfort, hygiene) • Accessibility (movement through bldg) • Structural Capacity (load handling) • Quality of Materials and Workmanship
What? Let’s look at these issues, one at a time
Configuration: You Decide… • Use: “Use Groups” (IBC Chapter 3). Yes, you decide—the code just tells you what to call it. • Size: Area, height, number of stories
Configuration: You Decide… And to a lesser degree… • Budget: To the degree that it permits use of more fire-resistant assemblies • Degree of Enclosure: Openness
Configuration: Code Sets… • Construction Classification (IBC Table 503), which establishes your options.
Configuration: Options • AFS: Automatic Fire Suppression. Doubles area, adds height. • Street Frontage: For Fire Dept access. Default is 25% • Compartmentation: Smaller compartments justify lower-rated assemblies
Fire-resistance: You Decide… • Construction Classification as just noted, as a function of intended configuration, using IBC Table 503
Fire-resistance: Code Sets… • Minimum Fire-Resistance Ratings, measured in hours
Fire-resistance: Code Sets… • And indirectly: Construction Assembly Options
Fire-resistance: Options… • Wrap required assemblies in preferable coverings. For example, enclose Type V (heavy timber) in drywall. • Provide minimum clearances. For example, keep ceilings 20’ above floors) • Change Construction Classification, backing up a step to rethink your earlier decision
Egress: You decide… • Use, Arrangement and Sizes of Rooms. So, until there’s a design, one can’t proceed. • Occupancy count, as a function of room use and size.
Egress: You decide… • Egress strategy. What method do you want to use to get occupants out? • 1 Direct Exits • 2 Horizontal Exits • 3 Vertical Exits • 4 Escapes
Egress: Code Sets… Basics • Minimum number of exits • Minimum provided Areas of Refuge
Egress: Code Sets… Distances • Minimum distance between exits
Egress: Code Sets… Distances • Maximum distance to closest exit
Egress: Code Sets… Distances • Maximum distance to an exit choice (“common path”)
Egress: Code Sets… Distances • Maximum distance travelled past exit (“dead end”)
Egress: Code Sets… Capacities • Minimum width of exit path
Egress: Code Sets… Capacities • Maximum encroachment on path • Door swings • Knobs • Handrails • Drinking Fountains
Egress: Code Sets… • When within the stair • When transferring between stairs • When discharging from the exit Enclosure of vertical exits
Egress: Options • Design the exit path cleverly: use horizontal exits, exit passages, etc. • Use AFS (sprinklers) • Try using “timed exiting” (if the design is amenable to it and if you have access to sophisticated fire-modeling software).
Habitability: You decide… • Which program spaces fall into which habitability category. Is it… • Habitable • Occupiable • Subsidiary • Uninhabitable
Habitability: Options • Not much. These standards really are minimums. Be honest in applying them. • Don’t design a space with less than 5’ of headroom, then let it be counted as useable SF in the sales brochures. • Don’t design a bedroom in a space that has less than 4% of operable window. • This does have implications for affordable housing. It’s intended to.
Accessibility: You decide… • How program spaces are to be arranged, both vertically and horizontally • Where operable devices (doors, vending machines, paper towel dispensers, etc.) are to be located
Accessibility : Code Sets… • Maximum difficulty of getting to program spaces (can deny access but not participation) • Minimum widths for doors (32”/36”) and halls (42”/60”) • Maximum slopes (1:12) and distances between landings (30” rise) at ramps • Vertical placement of operable devices (buttons, pulls, etc.) for reach
Accessibility : Code Sets… • Maximum difficulty of use • Grasping railings (1½” diameter, 1½” from wall) • Turning knobs and levers, grip-ability • Pushing doors open or closed • Minimum levels of dignity • No acceptable marginalization • Views past others
Accessibility : Options • Still very much a designer’s call. ADAAG and ANSI 117.1 provide some guidance. • Errors caught mostly by frustrated users rather than permit review process. • Enforced by lawsuit demanding compliance with ADA.
Structural Capacity: You decide… • Program, which determines anticipated usage loads (libraries, warehouses, factories, etc). • Location, with its associated wind, rain, and seismic loads • Massing, which determines where… • snow buildup might occur • seismic loads might concentrate.
Structural Capacity : Code Sets… • Minimum structural capacities (resistance to live load) based on intended use and (if relevant) massing • IBC Chapter 16
Structural Capacity : Options Options are often less needed since: • Codes mostly set minimum loads, not the way they are handled. • Requirements can usually be met without adversely affecting architecture. • The risk of failure is sufficient to discourage code avoidance.
Quality: You decide… • The materials from which to build, based both on design considerations and such code mandates as fire-resistance.
Quality : Code Sets… • Minimum standards for the manufacture and installation of those materials. • They usually do this by mandating standards written by other groups: • Publishers such as ANSI, ASTM • Trade associations that represent manufacturers such as BIA, AWI • Trade unions that represent installers
Quality : Options • Code mandates are minimums. It’s unlikely that avoiding them would carry substantive advantages. • Standards may not be available for some recently-developed materials. Without them, the materials may not be allowed. This can be frustrating, but there is usually no alternative.
The Bottom Line • Code officials want to protect the public. They understand that codes are only one way to increase predictability. • If you can demonstrate the safety of a non-compliant design (through testing, modeling, etc.), it’s quite possible that it will be approved.
Communicating Compliance • Indicateapplied codes (full name [IBC, IPC, NFPA 101, ANSI 117.1], year). • Show occupancy count: Floor plans that show populations in each room, plus location, configuration and width of egress paths • Summarize: Issue - Required - Provided
Getting Started • Use the Table of Contents to focus your research
Now It’s Your Turn Questions and Discussion