Prescriptive vs. Performance Building Codes- your thoughts?

[superchef]

Prescriptive vs. Performance Building Codes


The current research paper I am writing is a multiple-source essay. I am still focusing on the national fire problem and the cost to society but in this paper, I am looking at some of the issues for a more proactive approach to fire (prevention is proactive, suppression is reactive). I understand the basic differences between to above types of building codes. I have been to NIST, NFPA, and the ICC sites, but from what I could find, performance based codes are not widely used in the U.S. If you have time to throw your thoughts into this thread it will be greatly appreciated (or if you need to correct me!).

One thing I found interesting is that in New Zealand, the Building Act sets out the social objectives of a performance based building code, among those objectives are:

1.” to safeguard people from possible injury, illness or loss of amenity in the course of use of any building, including the reasonable expectations of any person authorized to enter the building for the purpose of rescue operations and fire fighting in response to “fire.
2. “provide protection to limit the extent and effects of the spread of fire; particularly with regard to household units and other residential units; and other property”

Do performance based codes supplement the prescriptive codes? What are some of the pros and cons of both?

The California Building Standards Commission recently voted to rescind adopting NFPA 5000, citing among other issues for rescinding it, that there would be a loss of potential insurance discounts because of poor ratings by the ISO of buildings and fire departments enforcing out of date codes during the time it would take to implement NFPA 5000. (CA did vote to adopt the IBC as the basis for the next CA Building Code)

Is this a flawed argument? If a building is built to code, when a new code is established, unless it is retroactive, would not that building still be within code? Is NFPA 5000 a performance based code? I could not figure that one out.

All comments are greatly appreciated.

Thanks

[FFFRED]

Prescriptive vs. Performance Building Codes...

As I understand them and what I think you are refering to..here are my quick thoughts.

Prescriptive codes are how we got soild building materials. Soild dependable fire walls. Dementional lumber and buildings that could stand even with heavy fire impingment for quite some time...

Performance Building Codes have brought us Open Web unprotected steel joists, C-Joists, OSB Trusses w gusset plates, sheetrock instead of Soild Masonry. World Trade Center (Trussed joists)...basicly cheap, worthless construction not fit for a taxpayer in East New York let alone Dwellings (private & multiple) and highrises.

JMO

FTM-PTB

[superchef]

That picture looks like one of those toothpick and popsicle stick houses you made as a kid. Thanks Fred. That is what I am looking for, your thoughts on the two codes. I am 200% in favour of increasing life safety for firefighters (and civilians). This paper needs to present the differing points of view objectively and look at the question of how we can prevent the next fire and firefighter injury and fatality. (If that can be done objectively!) I have already been accused of being biased.

[CJMinick390]

Fred, that picture speaks volumes. From the outside that building will look like a pretty substantial concrete block building. If you didn't see the inside before everything was buttoned up you would think you had pretty solid conventional construction. If you aren't aware of what is being built in your area, you can walk into some unexpected surprises when you go into a place like that.

[DepChief135]

The Building Code seems to be performance oriented, and relies on a lot of documentation to prove that the design meets the criteria established in the code. Many of the chapters indicate which engineering method you can use, load and resistance factor for example. Chapter 23 (wood design) is mostly performance, with the exception of 2308. This appears to be perscriptive. However, there are limitations on the size of the building; ie - no more than 3 stories tall, wall heights not over 10', truss / rafter span not over 40' etc. That doesn't take the seismic issues into account. The code does try to compensate for some of the issues we have with things like the construction in the photo. There are specific requirements for engineering documentation for a truss. The language is very clear, you have to have the info before starting construction. There is also some language about limiting the intertitial space in the picture to under 10,000 square feet, by installing a draft curtain, or separation, I think.