'Prescriptive' and Performance based codes?

[Benzerari]

What is the difference between 'prescriptive-based codes' and 'performance based-design codes' in regards to fire safety standards?

[Benzerari]

Is BS5839..., a ‘prescriptive based codes’, or ‘performance based design codes’, or a mixture of both?

[wee brian]

Prescriptive codes or requirements tell you what you should be doing - eg Smoke detectors must be possiitoned no more than 5m apart....

Performance based codes or requirements set a specific performance -  eg The fire detection system should be designed so that it detects a fire within 30 seconds (for this you need standard methods of calculation which cannot be varied)

Functional based requirements set out the objectives - eg A suitable fire detection system should be provided...(you can go all the way to - the building should be reasonably safe if there is a fire)

BS 5839 is esentially a prescriptive standard. This kind of standard is used by specifiers and regulators as a kind of shorthand. Rather than describing what they want in infinate detail (which they probably arent qualified to do) they just call up a standard spec.   There are sometimes functional nad perfermoance based elements to codes like this.

Most of the Building Regs requirements (in England and Wales) are functional.

A lot of people think that fire safety engineering design is performance based but it isn't (or c ertainly very rarely). FSE is usually used to show compliance with a functional requirement.

[Tom Sutton]

Sorry wee brian for being so thick but your abbreviation FSE what does it mean.

[wee brian]

FSE - Fire safety engineering

[Benzerari]

Prescriptive codes or requirements tell you what you should be doing - eg Smoke detectors must be possiitoned no more than 5m apart....

Performance based codes or requirements set a specific performance -  eg The fire detection system should be designed so that it detects a fire within 30 seconds (for this you need standard methods of calculation which cannot be varied)

Functional based requirements set out the objectives - eg A suitable fire detection system should be provided...(you can go all the way to - the building should be reasonably safe if there is a fire)

BS 5839 is esentially a prescriptive standard. This kind of standard is used by specifiers and regulators as a kind of shorthand. Rather than describing what they want in infinate detail (which they probably arent qualified to do) they just call up a standard spec.   There are sometimes functional nad perfermoance based elements to codes like this.

Most of the Building Regs requirements (in England and Wales) are functional.

A lot of people think that fire safety engineering design is performance based but it isn't (or c ertainly very rarely). FSE is usually used to show compliance with a functional requirement.

Thanks W. Brian, any more refinements guys 

[Benzerari]

A lot of people think that fire safety engineering design is performance based but it isn't (or certainly very rarely). FSE is usually used to show compliance with a functional requirement.

Fire safety engineering design uses engineering solutions such as CFD, PRA... approaches and it's all based on calculations, how that can not be performance based design W.Brian?

[Benzerari]

Also, I have heard that amongst the developed world, the British on 1985, followed by New Zealand on 1992, then Australia on 1995 were the first to publish performance-based design codes.

What are the British performance-based design codes, if other than BS5839?

[colin todd]

AD B

[wee brian]

The regs in UK NZ and AU are not performance based, they are functional.

Fire safety engineering is usually carried out using comparative studies against the codes rather than to meet a particular performance.

[Benzerari]

The regs in UK NZ and AU are not performance based, they are functional.

Fire safety engineering is usually carried out using comparative studies against the codes rather than to meet a particular performance.

W.Brian;

Your probably right but still, I couldn't get my head round in here, or may be I am confused, since I heard for the first time of the word 'functional codes'.

Do you mean functional is both 'prescriptive' and 'performance-based' combined together?

[wee brian]

In practice you could describe functional systems that way.

For England and Wales there are 5 functional requirements in the building regs relating to fire safety.

Approved Document B (AD B) is essentially a prescriptive code that provides an acceptable way of meeting those requirements.

However designers can adopt alternative approaches to compliance if they can satisfy the Building Control Body that their proposals are acceptable. This is usually done by demonstrating/arguing that the design offers a similar level of safety to the AD solution. You could call this a performance based approach but it isnt really a pure performance based design as performance is not specified in tangable terms.

[Benzerari]

In practice you could describe functional systems that way.

For England and Wales there are 5 functional requirements in the building regs relating to fire safety.

Approved Document B (AD B) is essentially a prescriptive code that provides an acceptable way of meeting those requirements.

However designers can adopt alternative approaches to compliance if they can satisfy the Building Control Body that their proposals are acceptable. This is usually done by demonstrating/arguing that the design offers a similar level of safety to the AD solution. You could call this a performance based approach but it isnt really a pure performance based design as performance is not specified in tangable terms.

So no thing else in UK closer to performance-based code apart from AD B, as Colin stated previously?

[CivvyFSO]

I think BS7974 might be close to what you are looking for.

[wee brian]

You've fallen into the trap Civvy. There's no performance specified in 7974 so it can't be a performance based code, now can it.