Single Exit from Basement (Commercial - M)

[eyan50495]

Hi All

So the Building Dept has reviewed our Life Safety drawings and determined that we need a second means of egress from a basement.

This is a Mercantile Occ. with a floor plate of 10,000 SF. The basement in question has 2 stairs, picture a box with one on the midpoint of the left side and one on the bottom left corner (both 1 hour fire rated). Due to a commercial kitchen located on the lower portion of this box, the 2nd stair on the bottom left only has a single corridor going towards it. In theory, you cannot access that 2nd stair without first passing the 1st / Middle Stair and going down a corridor, past the kitchen to access it.

The DOB would like us to created a rated corridor between both stairs and says that 2 means of egress are required regardless of the occupant load.

Although it wouldn't be the end of the world to create a rated corridor, it would create issues with the function of the kitchen and other staff (they need traffic doors).

Based on my understanding, Chapter 10 of IBC 2015 of NYS has 2 areas about Number of Exits / Exit Access. I believe 1006.3.1 Egress Based on Occupant Load is more relevant.

Our occupant load is 35 and the Common Path of Travel does not exceed 75'.

It states "Each story and occupied roof shall have the minimum number of independent exits, or access to exits, as specified in Table 1006.3.1. A single exit or access to a single exit shall be permitted in accordance with Section 1006.3.2."


Table 1006.3.1 states that the Min. # of Exits or Access to Exits Per Story for 1-500 occ. is 2.


Table 1006.3.2 Single Exits states:

A single exit or access to a single exit shall be permitted from any story or occupied roof where one of the following conditions exists:

1. The occupant load, number of dwelling units and common path of egress travel distance does not exceed the values in Table 1006.3.2(1) or 1006.3.2(2).

Going to Table 1006.3.2(2) Stories with 1 Exit or Access to 1 Exit for Other Occ., it states that:

The First story above or below grade plane with an M Occ. must have no more than 49 Occ./Story and a Max. CPT 75'.

We meet both? Am I missing something?

 

[ADAguy]

You are trapped below grade if only 1 exit is provided.

 

[RLGA]

How can you have a common path of egress travel of 75 feet or less when the area of the basement is 10,000 sq. ft.?

 

[cda]

You do know this is a building code question

 

[cda]

Hi All

So the Building Dept has reviewed our Life Safety drawings and determined that we need a second means of egress from a basement.

This is a Mercantile Occ. with a floor plate of 10,000 SF. The basement in question has 2 stairs, picture a box with one on the midpoint of the left side and one on the bottom left corner (both 1 hour fire rated). Due to a commercial kitchen located on the lower portion of this box, the 2nd stair on the bottom left only has a single corridor going towards it. In theory, you cannot access that 2nd stair without first passing the 1st / Middle Stair and going down a corridor, past the kitchen to access it.

The DOB would like us to created a rated corridor between both stairs and says that 2 means of egress are required regardless of the occupant load.

Although it wouldn't be the end of the world to create a rated corridor, it would create issues with the function of the kitchen and other staff (they need traffic doors).

Based on my understanding, Chapter 10 of IBC 2015 of NYS has 2 areas about Number of Exits / Exit Access. I believe 1006.3.1 Egress Based on Occupant Load is more relevant.

Our occupant load is 35 and the Common Path of Travel does not exceed 75'.

It states "Each story and occupied roof shall have the minimum number of independent exits, or access to exits, as specified in Table 1006.3.1. A single exit or access to a single exit shall be permitted in accordance with Section 1006.3.2."


Table 1006.3.1 states that the Min. # of Exits or Access to Exits Per Story for 1-500 occ. is 2.


Table 1006.3.2 Single Exits states:

A single exit or access to a single exit shall be permitted from any story or occupied roof where one of the following conditions exists:

1. The occupant load, number of dwelling units and common path of egress travel distance does not exceed the values in Table 1006.3.2(1) or 1006.3.2(2).

Going to Table 1006.3.2(2) Stories with 1 Exit or Access to 1 Exit for Other Occ., it states that:

The First story above or below grade plane with an M Occ. must have no more than 49 Occ./Story and a Max. CPT 75'.

We meet both? Am I missing something?

Can you post a simple floor plan

 

[steveray]

How can you have a common path of egress travel of 75 feet or less when the area of the basement is 10,000 sq. ft.?

Fist thing I thought...Also look at T1006.3.1 at 10,000 ft you are less than 49 OL?

 

[e hilton]

Applying the ROCS ... rule of common sense ... 10,000 underground with one exit is just wrong. If it was above ground you could say that breaking out a window would be an emergency exit, but that doesn’t work here.

 

[eyan50495]

Can you post a simple floor plan

Hi All, Sorry for posting in the wrong forum. I was thinking Fire and put this in the Fire Code instead of the BC.

Here is a simple floor plan: https://www.dropbox.com/s/850mjzgjf6ei7bp/BASEMENT PLAN EGRESS.pdf?dl=0

There are 2 rated stairs. The store designer created a very large kitchen which cut off Stair B and increased our CPT. We then added a 1 HR Rated Exit Passage to effectively decrease the CPT. The Inspector says # of Egress Exits are NOT based on Occupant Loads and says we need to rate the hall between the 1 Hr Rated Exit Passage and Stair B. There is a kitchen with traffic doors and restrooms, storage closets on that hall so we'd have to change those doors to become rated.

Going back to the original question:
1) Regardless of whether this is a poor layout, does a basement that has less than 49 Occ. and less than 75' CPT require 1 Exit? Can someone clarify that code section above?

2) I'm getting confused - I thought you were not allowed to have other uses (i.e. restrooms, kitchen doors, closets) within a rated corridor? Or am I getting that confused with an Exit Passage?

Thanks again!

 

[eyan50495]

Fist thing I thought...Also look at T1006.3.1 at 10,000 ft you are less than 49 OL?

Hi Steveray, yep. We are under 49 as most of the space is Storage / Kitchen. We are also under the CPT because of an added Rated Exit Passageway. I just posed a link to a simple floor plan above.

 

[cda]

So the only use of the basement

is storage and kitchen??

 

[cda]

Thinking yes provide access to both stairs

May not have to be rated


I assume a fire sprinkler system already installed?????

 

[eyan50495]

Thinking yes provide access to both stairs

May not have to be rated


I assume a fire sprinkler system already installed?????

Yes, only storage and a commercial kitchen. The building is fully sprinkler'd but has not been installed. Right now they have not started the fitout. the only things that are done are the stair openings.

I also thought it would not have to be rated as it is sprinkler'd however the Inspector was saying that if Stair A become obstructed, people would have to leave a fire rated passage into a non-rated corridor and go past a Kitchen to get to the secondary stair. I haven't shown him the BC on Table 1020.1 which shows a Corridor in an M Occ. would not require a fire rating.

 

[cda]

Well if two exits are required,

To me appears your current set up, creates dead end corridor issue.

Ask the nice reviewer what code sections require rated enclosure

Also appears the kitchen has a wall between the exit way and kitchen, so a person is not walking through the kitchen.


Plus with the storage wide open, should be able to move walls to isolate/separate the two stairs

 

[RLGA]

Fist thing I thought...Also look at T1006.3.1 at 10,000 ft you are less than 49 OL?

steveray, did you mean Table 1006.2.1? If so, then that is for spaces and not stories.

Eyan50495, according to your drawing, the way you measured the CPET is incorrect--diagonally through a room is not considered "the natural an unobstructed path" (in a mercantile storeroom, I seriously doubt the room will be so open to afford such a direct path).

Once someone enters a protected means of egress, the protection cannot be reduced. Occupants that enter the exit passageway from the open storage must be provided equal protection to either exit if both exits are to be considered for the open storage egress. To reach the second exit, an occupant from the open storage must leave the protection of the exit passageway.

Can the open storage space have a single exit? Yes, per Table 1006.3.2(2); however, as I previously stated, the common path appears to exceed the maximum of 75 feet. If the building will be fully sprinklered throughout, then this distance can be increased to 100 feet per footnote 'b' of Table 1006.3.2(2), which may help out. The kitchen and the smaller rooms will have two means of egress, but you need to make sure that they are separated by 1/3 the overall diagonal of the area they serve (not the entire basement).

 

[eyan50495]

Well if two exits are required,

To me appears your current set up, creates dead end corridor issue.

Ask the nice reviewer what code sections require rated enclosure

Also appears the kitchen has a wall between the exit way and kitchen, so a person is not walking through the kitchen.


Plus with the storage wide open, should be able to move walls to isolate/separate the two stairs

From our understanding, we do not have a dead end condition as everything is within 50' of Dead End and or open since it is stock.

Exactly, no one is egressing through the kitchen only coming out from it to either side.

I have put the same code sections and corridor rating code section to the DOB Director, let's see what he says.

 

[eyan50495]

steveray, did you mean Table 1006.2.1? If so, then that is for spaces and not stories.

Eyan50495, according to your drawing, the way you measured the CPET is incorrect--diagonally through a room is not considered "the natural an unobstructed path" (in a mercantile storeroom, I seriously doubt the room will be so open to afford such a direct path).

Once someone enters a protected means of egress, the protection cannot be reduced. Occupants that enter the exit passageway from the open storage must be provided equal protection to either exit if both exits are to be considered for the open storage egress. To reach the second exit, an occupant from the open storage must leave the protection of the exit passageway.

Can the open storage space have a single exit? Yes, per Table 1006.3.2(2); however, as I previously stated, the common path appears to exceed the maximum of 75 feet. If the building will be fully sprinklered throughout, then this distance can be increased to 100 feet per footnote 'b' of Table 1006.3.2(2), which may help out. The kitchen and the smaller rooms will have two means of egress, but you need to make sure that they are separated by 1/3 the overall diagonal of the area they serve (not the entire basement).

Hi Ron,

Thanks for the response. The diagram floor plan wasn't great but in reality, the CPET does go around the storage fixtures (gondola shelving) and is within 75' from all points (most are actually 55').

The doors of the kitchen are separated by 1/3 and luckily we also have 70' CPET around all the kitchen equipment. Unfortunately, we cannot take the 25' bonus because our Occ. is an M.

Based on 1020.1, we would not need to rate the corridor between the 2 stairs as we have a sprinkler system. BUT, if someone leaves that exit passageway into the unrated corridor, the fire rating would be reduced. But if 2 exits are not required then....? Just getting a little confused around the circular thinking.

Thanks

 

[tmurray]

I wouldn't buy your path of travel, unless the furniture is mechanically fixed in place (i.e., screwed down).

 

[eyan50495]

I wouldn't buy your path of travel, unless the furniture is mechanically fixed in place (i.e., screwed down).

They will likely anchor the shelving down for tipping hazards. But the CPT does go around all of them.

 

[RLGA]

Hi Ron,

Thanks for the response. The diagram floor plan wasn't great but in reality, the CPET does go around the storage fixtures (gondola shelving) and is within 75' from all points (most are actually 55').

The doors of the kitchen are separated by 1/3 and luckily we also have 70' CPET around all the kitchen equipment. Unfortunately, we cannot take the 25' bonus because our Occ. is an M.

Based on 1020.1, we would not need to rate the corridor between the 2 stairs as we have a sprinkler system. BUT, if someone leaves that exit passageway into the unrated corridor, the fire rating would be reduced. But if 2 exits are not required then....? Just getting a little confused around the circular thinking.

Thanks

The main occupancy group is Group M (on the first story, I assume), but your basement is a combination of Group S-1 and F-1, so the additional distance is permitted.

 

[eyan50495]

Well if two exits are required,

To me appears your current set up, creates dead end corridor issue.

Ask the nice reviewer what code sections require rated enclosure

Also appears the kitchen has a wall between the exit way and kitchen, so a person is not walking through the kitchen.


Plus with the storage wide open, should be able to move walls to isolate/separate the two stairs

The review got back to me and said the following:

"The cellar is the SECOND story. The FIRST story is the floor above. Therefore two means of egress are required based on the occupant load. "

 

[cda]

The review got back to me and said the following:

"The cellar is the SECOND story. The FIRST story is the floor above. Therefore two means of egress are required based on the occupant load. "

Ask for code section, to back it up

 

[steveray]

I would have to think on it a bit, but it seems like you have access to the same exit passageway, not two different ones....

 

[cda]

I think you need to start over


Lose the exit passageway

Move a wall or two

 

[eyan50495]

I think you need to start over


Lose the exit passageway

Move a wall or two

I should have done this a bit earlier but here is the ACTUAL plan: https://www.dropbox.com/s/8r1p8877yz7bs3u/BASEMENT PLAN EGRESS 2.pdf?dl=0

And the code he is referring to Table 1006.3.2(2) which says 'First Story Above or Below Grade Plane'. I can see his interpretation saying that the Basement is NOT the First Story.