Tall Buildings after NFPA or IFC - number of escape routes

[Anton David]

Can anyone give clear picture of the fire requirements for tall Buildings after NFPA or IBC?

In UK and Denmark you allowed to build a single escape stairs for residential buildings but only if the stairs is a safe stair i.e. a pressurized stair. For all other occupancies two escape routes need to be provided or if you have more than one occupantcy.

But what is the stair requirement for tall buildings if you follow NFPA/IFC say for 80m tall height?
Or for 100-120m tall height?

 

[stookeyfpe]

Jens:

The IBC requirements for means of egress are based on occupant load, exit width, exit travel distance, and the distance to the property line. This forum cannot offer an answer to your question. You referenced NFPA 101 – it has the same design philosophy. So if you want an opinion, you need to provide enough information.

If you are a designer, you should be able to figure these basics on your own. If not, you need to retain design assistance. FYI, 80M is a high rise in the USA.

Good luck in your design.

 

[Anton David]

Thanks Stookeyfpe - this i clear and I agree with you.
I am just looking for a short second opinion:

Design basic information for the tall buildings are
* Each level approx. 625 m2 (gross area)
* Only residentials on each level (5-6 apartments
* Heights of buidlings: 80-120my
* Fireman elevators installed
* Width of stairs: 1.2m
* Presurrized escape stair and a lobby.
* Two-communication system
* Local automatic fire alarm (warning) in each apartment
* Residential sprinklers i each apartment
* Risers with boosters on each stair level.
* Fire service truck lader up to 22m on facades.

Question for second opinion:
I some European the prescriptive fire code states that it allowed to have a single escape staircase in multi-storey building but only for residential use. However, the height limit is not stated. So the question is - what is an appropriate max. height?

I have my own opinion on this issue: I simply don't like it but have no current local fire regulation to use on this feeling.

Thanks.

 

[stookeyfpe]

Question for second opinion:
I some European the prescriptive fire code states that it allowed to have a single escape staircase in multi-storey building but only for residential use. However, the height limit is not stated. So the question is - what is an appropriate max. height?

I can't offer an answer because US building codes require two means of egress stairs in a high rise building, regardless of occupancy classification. Possibly the European codes assume that a fire in a single dwelling unit will not be expected to extend beyond the apartment of fire origin based on other controls prescribed by law. Or maybe they allow a single stair because of stair pressurization. I would not be comfortable with that design unless it incorporated redundant water supplies to the sprinkler system, standby power for the stair pressurization system, and limit the exit travel distance. I would also want a timed egress study (based on an assumed hypothetical failure of the sprinkler system) to determine the egress time before conditions in the apartment of fire origin developed carbon monoxide concentrations that could incapacitate the occupants.

 

[Anton David]

Thanks stookeyfpe,

I agree and see many of your points stated.

I have some comments to your thoughts: When you say ..."and limit the exit travel distance". What do you mean by that - and how do you calculate it what is the maximum number? I think I have a clue but I am not sure. E.g. Is the Maximum Travel Distance 200 feet = 61m (I guess this is the true “3D-walking” distance on the stair).

Another view – I have heard that in NYC scissor stairs are accepted fi it is R-2 occupancy with 2-hr-rated masonry (or equivalent) enclosure & separation and 15 feet separation between exit doors. And that exit doors from scissor to terrain shall be separated from each other. And the building shall have stairs access to roof (why for helicopter?) What else is the requirement for this concept to get approval? Any maximum height for this concept?

 

[cdafd]

Suggest you find someone near you that has designed to USA standards and set down so they can go over a high rise design.

https://www.bellevuewa.gov/pdf/Development Services/B-2_2012_High_Rise_Checklist.pdf

Based on the 2012 ibc

http://codes.iccsafe.org/app/book/toc/2012/I-Codes/2012 IBC HTML/index.html

http://specsandcodes.typepad.com/the_code_corner/2013/02/high-rise-buildings.html:::::

Means of Egress

Several changes and additions to the means of egress requirements have been introduced in the IBC for high-rise buildings. Some of these new requirements were controversial and were opposed by organizations such as the Building Owners and Managers Association (BOMA).
The most controversial requirement was an additional stairway for buildings more than 420 feet in height (IBC Section 403.5.2). For example, a building with multiple stories and an occupant load of 500 or less for each story would be required to have a minimum of two exits from each story. However, if that building exceeds 420 feet in height, then a third stairway would be required. This is to overcome the problem encountered at the WTC in 2001, when occupants were egressing down the stairs while firefighters were trying to work their way up the same stairs. Furthermore, if one exit is removed, the remaining exits must provide the total exit width calculated per Section 1005.1. This additional stairway requirement applies to all applicable high-rise buildings in all occupancy groups except for Group R-2.
The exception to the additional stairway requirement is to provide an occupant evacuation elevator per IBC Section 3008. See The Code Corner No. 38, “Elevators,” for a detailed discussion on occupant evacuation
elevators.
Also related to exit stairways is the remoteness requirement (IBC Section 403.5.1). The remoteness requirement states that interior exit stairways be separated by a distance not less than 30 feet or ¼ of the overall diagonal of the building or area to be served, whichever is less. If three or more exit stairways are provided, at least two shall comply with the remoteness requirement. If interlocking stairs are provided, the stairs will be counted as a single exit stairway.
Per IBC Section 403.5.3, doors leading into exit stairways are permitted to be locked from the stairway side, provided that all doors can be unlocked—not unlatched—simultaneously upon a signal from the fire command center, which is discussed later in this article. For stairways where doors are locked from the stairway side, a two-way communication system connected to a “constantly attended station” must be provided on the stairway side at every fifth floor.
Stairways serving high-rise buildings are required to be constructed as smokeproof enclosures per IBC Section 403.5.4, which references IBC Sections 909.20 and 1022.10. Section 1022.10 establishes the basic requirements for interior exit stairways within smokeproof enclosures. The smokeproof enclosure must be accessed through a vestibule4 unless the pressurization alternative is implemented. The smokeproof enclosure must terminate at an exit discharge or a public way; however, it can be extended using an exit passageway. To do so, the exit passageway must be separated from the smokeproof enclosure with a fire door and have no other openings other than the door to the exit discharge. Other openings are permitted into the exit passageway provided it is accessed by vestibules like the smokeproof enclosure or is pressurized in the same manner as the smokeproof enclosure. If the exit passageway is pressurized in the same manner as the smokeproof enclosure, then the fire barrier and fire door between the smokeproof enclosure and exit passageway may be eliminated. Finally, the last exception permits the smokeproof enclosure to egress through areas on the level of exit discharge per IBC Section 1027.
Another requirement specific to high-rise buildings is the use of luminous markings for the egress path per IBC Section 1024. The only occupancy groups to which this applies are A, B, E, I, M, and R-1. This section explains in great detail what needs to be marked and how. If the stairway egresses through areas on the level of exit discharge, such as a lobby, the markings are not required in those areas.
The last egress requirement for high-rise buildings is actually an exception. IBC Section 1029 requires that Group R-2 occupancies be provided with emergency escape and rescue openings for all sleeping rooms in stories below the fourth story. However, because of the added protection and safety measures required of high-rise buildings, IBC Section 403.5.6 exempts high-rise buildings from having these openings.

 

[stookeyfpe]

Jens:

I am not going to engage in a discussion about scissor stairs because they are trying to be resurrected in certain, very tall and slender high rise buildings. I am dealing with this on a project. I am not an advocate.

I have done all I can do. Good luck and from the USA I wish you happy holidays as next week we begin Thanksgiving where we celebrate family and the beginning of our governance as a nation. Friday is my last work day and I am excited about my favorite holiday of the year.

CDA:

Austin, Tx currently has 29 high rise buildings in design or construction. We have 200 high rise buildings in our jurisdiction. A reference to Bellvue, WA will just be a code regurgitation and it's cursory. As a jurisdiction with a population of 900,000 with 11 fire protection engineers employed by the Fire Department (me being one of them), I think we understand these issues and I respect Jens problem.

Have a nice Thanksgiving. Good bye.