Unobstructed egress in electrical room

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earshavewalls

Senior Member
I have a designer who is adding a third main service in an existing electrical room. The existing equipment is a 3,000amp POCO pull section with distribution bussing; a 1,400amp MSB1 distribution main (w/gfi protection); and an existing MSB2, with 1,600amp distribution. They wish to add MSB3, which is a new 800amp distribution section. All existing equipment is installed against the walls in the room, which has only one exit, but has all required clearances provided. The new MSB3 is shown as being installed in the middle of the open space in the room. The working clearances appear to be compliant, but does this now create an obstruction to egress from this room? If working on equipment that will now be behind MSB3 (in relation to the only exit), is the means of egress now obstructed?
The designer is submitting example plans showing that someone in the room can go around the equipment to get to the exit. However, I still feel that this creates an obstruction to egress in this room. I have attached one of their drawings where they are demonstrating what they consider to be unobstructed egress from this electrical room. The unlabeled sections are distribution to several tenants in this mall.

Any opinions would be welcome.

Thank you,
Wayne Webb
Assistant Engineer
MEP Plan Check
 

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Gregg Harris

Senior Member
Location
Virginia
Occupation
Electrical,HVAC, Technical Trainer
I have a designer who is adding a third main service in an existing electrical room. The existing equipment is a 3,000amp POCO pull section with distribution bussing; a 1,400amp MSB1 distribution main (w/gfi protection); and an existing MSB2, with 1,600amp distribution. They wish to add MSB3, which is a new 800amp distribution section. All existing equipment is installed against the walls in the room, which has only one exit, but has all required clearances provided. The new MSB3 is shown as being installed in the middle of the open space in the room. The working clearances appear to be compliant, but does this now create an obstruction to egress from this room? If working on equipment that will now be behind MSB3 (in relation to the only exit), is the means of egress now obstructed?
The designer is submitting example plans showing that someone in the room can go around the equipment to get to the exit. However, I still feel that this creates an obstruction to egress in this room. I have attached one of their drawings where they are demonstrating what they consider to be unobstructed egress from this electrical room. The unlabeled sections are distribution to several tenants in this mall.

Any opinions would be welcome.

Thank you,
Wayne Webb
Assistant Engineer
MEP Plan Check

I would say that it is an obstruction. A clear path is from point A to B and not an open trail leading out.
 

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
You might only need one exit, regardless of the layout of the new and existing gear. I think it might make a difference knowing which code cycle applies. Also, it might make a difference if one or more of the existing components are more than 6 feet wide. Can you fill in those details for us?

But to go straight to your question, if the applicable edition of the code requires an unobstructed path from the working space for the existing MSB2 to the only exit, then placing the new MSB3 in the location shown would create a violation. There is no doubt in my mind on this point.
 

earshavewalls

Senior Member
We are on the 2011 NEC (2013 California Electrical Code), which does require an unobstructed means of egress from this room because of the 3,000amp pull section and a 1,600, 1,400, and 800amp service sections also in the room.
 

mgookin

Senior Member
Location
Fort Myers, FL
I have a designer who is adding a third main service in an existing electrical room. The existing equipment is a 3,000amp POCO pull section with distribution bussing; a 1,400amp MSB1 distribution main (w/gfi protection); and an existing MSB2, with 1,600amp distribution. They wish to add MSB3, which is a new 800amp distribution section. All existing equipment is installed against the walls in the room, which has only one exit, but has all required clearances provided. The new MSB3 is shown as being installed in the middle of the open space in the room. The working clearances appear to be compliant, but does this now create an obstruction to egress from this room? If working on equipment that will now be behind MSB3 (in relation to the only exit), is the means of egress now obstructed?
The designer is submitting example plans showing that someone in the room can go around the equipment to get to the exit. However, I still feel that this creates an obstruction to egress in this room. I have attached one of their drawings where they are demonstrating what they consider to be unobstructed egress from this electrical room. The unlabeled sections are distribution to several tenants in this mall.

Any opinions would be welcome.

Thank you,
Wayne Webb
Assistant Engineer
MEP Plan Check


I think it's fine. There's no requirement for egress to be in a straight line.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
The discussion in the Mike Holt clip about an egress route being behind the dead back of a row of equipment seems to support that view too.

Tapatalk!
 

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
We are on the 2011 NEC (2013 California Electrical Code), which does require an unobstructed means of egress from this room because of the 3,000amp pull section and a 1,600, 1,400, and 800amp service sections also in the room.
I don't know if California altered this section, but the 2011 NEC does not require the second exit unless a panel is at least 1200 amps AND IS over six feet wide. Are any of the 3000, 1600, or 1400 panels over six feet wide?
 

charlie b

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Location
Lockport, IL
Occupation
Retired Electrical Engineer
I think it's fine. There's no requirement for egress to be in a straight line.
With your kind permission, I must strongly disagree. The words in the code are, "Where the location permits a continuous and unobstructed way of egress travel. . . ." I cannot think of any plausible meaning of the word "continuous," other than in the context of a straight line path.
The discussion in the Mike Holt clip about an egress route being behind the dead back of a row of equipment seems to support that view too.
I don't know about that clip. If you can post a link, that might help. But I will say, for what little this is worth, that the NEC Handbook, Exhibit 110.16, very clearly backs up my point of view. It shows a board for which travel from the rear access area would require the worker to walk around the board, and it states that this would not meet the requirement for a continuous and unobstructed path.





 

mgookin

Senior Member
Location
Fort Myers, FL

With your kind permission, I must strongly disagree. The words in the code are, "Where the location permits a continuous and unobstructed way of egress travel. . . ." I cannot think of any plausible meaning of the word "continuous," other than in the context of a straight line path.

I don't know about that clip. If you can post a link, that might help. But I will say, for what little this is worth, that the NEC Handbook, Exhibit 110.16, very clearly backs up my point of view. It shows a board for which travel from the rear access area would require the worker to walk around the board, and it states that this would not meet the requirement for a continuous and unobstructed path.



Disagreement is good; it brings more information to the table from which we can make a more informed decision.

Regarding that Exhibit 110.16, does that "board for which travel from the rear access area would require the worker to walk around the board" encroach the required width? As to what is the required width, I'd say 36" because a mechanical room is exempt from accessibility and you surely don't have 50 people in there, so you don't need 44" unless something in NEC is requiring it.
 

charlie b

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Location
Lockport, IL
Occupation
Retired Electrical Engineer
Regarding that Exhibit 110.16, does that "board for which travel from the rear access area would require the worker to walk around the board" encroach the required width?
No, that is not the issue. I will try to attach a copy of the page. The exhibit to which I refer is on the top left of the page, and is the lower of the two images in that box. The access panel to the left has enough working clearance, as does the one on top of the image. But in order to get from the area behind the board to the exit door, a person would have to make a right turn, before heading towards the exit door. The text below the image states that this would not be acceptable, if the board were 1200 amps or more and if it were more than 6 feet wide.
 

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mgookin

Senior Member
Location
Fort Myers, FL
No, that is not the issue. I will try to attach a copy of the page. The exhibit to which I refer is on the top left of the page, and is the lower of the two images in that box. The access panel to the left has enough working clearance, as does the one on top of the image. But in order to get from the area behind the board to the exit door, a person would have to make a right turn, before heading towards the exit door. The text below the image states that this would not be acceptable, if the board were 1200 amps or more and if it were more than 6 feet wide.

Looks like we need OP to dimension his drawing.
There's a good read at http://www.mikeholt.com/instructor2/img/product/pdf/11NEC101-1076-sample.pdf
And it's not 36" but 3-1/2' (42")
 

Gregg Harris

Senior Member
Location
Virginia
Occupation
Electrical,HVAC, Technical Trainer

With your kind permission, I must strongly disagree. The words in the code are, "Where the location permits a continuous and unobstructed way of egress travel. . . ." I cannot think of any plausible meaning of the word "continuous," other than in the context of a straight line path.

I don't know about that clip. If you can post a link, that might help. But I will say, for what little this is worth, that the NEC Handbook, Exhibit 110.16, very clearly backs up my point of view. It shows a board for which travel from the rear access area would require the worker to walk around the board, and it states that this would not meet the requirement for a continuous and unobstructed path.






I would agree, the unobstructed means of egress is clear. If an incident where to occur you should be able to evacuate the room from point A to B without going around any obstructions in the path.
 

Wenty4

Member
Location
Raymond, NH, USA
Unobstructed egress in electrical room

Whether or not it is obstructed you are required to have panic hardware and the door must open in the direction of travel 110.26 (3), but unobstructed is not required per 110.26 (2)(a)
 

sandsnow

Senior Member
Looks to me as though this could comply but without dimensions, I'm not sure.

One thing to reemember is that it is the workspace is what has to have entrance and egress. The edge of the workspace is well away from the door.

Charlie, I don't get the "continuous straight line". Maybe not an official NFPA definition, but from google - forming an unbroken whole; without interruption.

If we have two rows of equipment with an entrance at each end and then "fold" that line up into a horseshoe, it would be fine - no? Seems to me the same thing happening here.
 

charlie b

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Location
Lockport, IL
Occupation
Retired Electrical Engineer
If that were true there would be no such thing as dead end or common path of travel.
I don't know what those two phrases mean. Can you post a sketch or point to a site that shows how those phrases tie in to a discussion of working clearance and path of egress?

 

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
If we have two rows of equipment with an entrance at each end and then "fold" that line up into a horseshoe, it would be fine - no? Seems to me the same thing happening here.
Each switchboard within a horseshoe line up will have its own working space, and there will be overlapping areas of working space. If the exit door is located such that you could stand anywhere within the combined working spaces of the horseshoe, and walk directly to the exit door, then you will have an acceptable installation. By that I mean if the equipment meets the 1200 amp and 6 foot rules that bring the "two exits" rule into play, and that allow you to look into the "unobstructed path" exception, then the installation is in compliance.

However, the sketch provided by the OP is not a horseshoe. It was close to a horseshoe before the MSB3 was inserted in the middle of the room. But once MSB3 is installed in the location shown, you have an obstruction between the working space for MSB2 and the exit door.

 

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
Charlie, I don't get the "continuous straight line". Maybe not an official NFPA definition, but from google - forming an unbroken whole; without interruption.
Again, looking at the OP's sketch, and considering a person standing in the working space in front of MSB2, how can you say that the location of MSB3 does not constitute an "interruption" in the path to the door?

 

mgookin

Senior Member
Location
Fort Myers, FL
I don't know what those two phrases mean. Can you post a sketch or point to a site that shows how those phrases tie in to a discussion of working clearance and path of egress?


COMMON PATH OF EGRESS TRAVEL. That portion of exit access which the occupants are required to traverse before two separate and distinct paths of egress travel to two exits are available. Paths that merge are common paths of travel. Common paths of egress travel shall be included within the permitted travel distance.


1018.4 Dead ends.

Where more than one exit or exit access doorway is required, the exit access shall be arranged such that there are no dead ends in corridors more than 20 feet (6096 mm) in length.

Exceptions:


1. In occupancies in Group I-3 of Occupancy Condition 2, 3 or 4 (see Section 308.4), the dead end in a corridor shall not exceed 50 feet (15 240 mm).
2. In occupancies in Groups B, E, F, I-1, M, R-1, R-2, R-4, S and U, where the building is equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1, the length of the dead-end corridors shall not exceed 50 feet (15 240 mm).
3. A dead-end corridor shall not be limited in length where the length of the dead-end corridor is less than 2.5 times the least width of the dead-end corridor.



1014.3 Common path of egress travel.

In occupancies other than Groups H-1, H-2 and H-3, the common path of egress travel shall not exceed 75 feet (22 860 mm). In Group H-1, H-2 and H-3 occupancies, the common path of egress travel shall not exceed 25 feet (7620 mm). For common path of egress travel in Group A occupancies and assembly occupancies accessory to Group E occupancies having fixed seating, see Section 1028.8.

Exceptions:


1. The length of a common path of egress travel in Group B, F M and S occupancies shall not be more than 100 feet (30 480 mm), provided that the building is equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.1.
2. Where a tenant space in Group B, S and U occupancies has an occupant load of not more than 30, the length of a common path of egress travel shall not be more than 100 feet (30 480 mm).
3. The length of a common path of egress travel in a Group I-3 occupancy shall not be more than 100 feet (30 480 mm).
4. The length of a common path of egress travel in a Group R-2 occupancy shall not be more than 125 feet (38 100 mm) within the dwelling unit, provided that the building is protected throughout with an approved automatic sprinkler system in accordance with Section 903.3.1.1 or 903.3.1.2 otherwise 75 feet.
5. Where a tenant space in Group A occupancy has an occupant load of more than 50, the length of a common path of egress travel shall not be more than 20 feet (6098 mm).
6. The common path of egress travel in Group R-1 and R-2 occupancies shall not exceed 35 feet (10 668 mm). Travel within a guestroom, guest suite or dwelling unit shall not be included when calculating the common path of travel. The common path of egress travel in occupancy Groups R-1 and R-2 shall not exceed 50 feet (15 240 mm) provided the building is protected throughout by an approved, automatic sprinkler system in accordance with Section 903.3.1.1.
7. The common path of egress travel in occupancies in Groups F and S shall be 50 feet (15 240 mm) in unsprinklered buildings.
8. The common path of egress travel in Group S-2 Parking Garages shall be 50 feet (15 240 mm).
9. In occupancy Group S-2 common paths of egress travel shall not be limited.
10. In occupancy Group H common paths of egress travel shall be prohibited.
 
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