Garage Open Air Calculations

[Papio Bldg Dept]

Now that we got iodinej's question out of the way, I hope you really are not requiring parking garage lighting levels 10 times higher than the IESNA levels. IBC 1205 requires 10 fc, whereas IESNA is 1 fc. IECC, which is based on IESNA lighting values, has a LPD of 0.3 w/sf for parking garage lighting. How do you meet that with lighting levels 10 times as high as the energy code is expecting?

this is how I see it...just because it is an open parking garage, does not mean you dismiss Chapter 12 carte blanche. The IECC does not trump the IBC in my opinion.

2009 IECC Intent. This code is not intended to abridge safety, health or environmental requirements contained in other applicable codes or ordinances.

2006 IBC, Section 1205 is typically only applicable for 1205.4 & 1205.5 (which references 1006.1). I do not require the 10 f/c as noted in 1205.3 for open parking garage areas. I do, however, see it as a building, but as mtlogcabin stated, by definition, the open areas, are not a room, and thereby those areas of the building are not an occupiable space (albeit occupied by cars ) or interior environment. As a building, it has an occupant load (which is part of the gray area i guess), and it shall meet the requirements for means of egress as established in Chapter 10, as well as Chapter 12 for any interior areas environments, rooms or occupiable spaces (i.e., ticket booths, enclosed stairwells, toilet rooms (per Table 2902.1), etc.).

 

[Coug Dad]

Let me throw in this wrinkle, since the 2006 IBC, what is the required head clearance in a parking garage? It looks like Chapter 10 kicks you into 7'-6" clear for means of egress.

 

[mark handler]

SECTION 406 MOTOR-VEHICLE-RELATED OCCUPANCIES

406.2.2 Clear height. The clear height of each floor level in vehicle and pedestrian traffic areas shall not be less than 7 feet....

406.3.8 Means of egress. Where persons other than parking attendants are permitted, open parking garages shall meet the means of egress requirements of Chapter 10.

So those areas of Means of egress, must be 7'-6", other areas must be 7 feet.

 

[codeworks]

ventilation is required because, let see, when you drive in you park the car ( it was running, emiiting fumes) when you are walking out of the garage, you now occupy it, sorry for the sarcasm, however, any parking garage i've ever been in was occupied by me and who ever else was in it, people come and go all day long, so it's occupied, it may not be a habitable space, no ones going to live there, it is however occupied. and there are clearer lines for habitable space, look in 2006 ibc definitions, page 15, then on page 17, we have the definition of occupiable space

 

[Coug Dad]

SECTION 406 MOTOR-VEHICLE-RELATED OCCUPANCIES406.2.2 Clear height. The clear height of each floor level in vehicle and pedestrian traffic areas shall not be less than 7 feet....

406.3.8 Means of egress. Where persons other than parking attendants are permitted, open parking garages shall meet the means of egress requirements of Chapter 10.

So those areas of Means of egress, must be 7'-6", other areas must be 7 feet.

Exactly the point Mark. If the drive lanes are the means of egress access to the stairs in a public garage, is 7 foot or 7'-6" required.

 

[mtlogcabin]

401.1 Detailed use and occupancy requirements.

In addition to the occupancy and construction requirements in this code, the provisions of this chapter apply to the special uses and occupancies described herein.

406.2.2 Clear height.

The clear height of each floor level in vehicle and pedestrian traffic areas shall not be less than 7 feet (2134 mm). Vehicle and pedestrian areas accommodating van-accessible parking required by Section 1106.5 shall conform to ICC A117.1.

The minimum ceiling heights of Chapter 10 do not apply to parking garages pedestrian traffic areas.

 

[mtlogcabin]

Now that we got iodinej's question out of the way, I hope you really are not requiring parking garage lighting levels 10 times higher than the IESNA levels. IBC 1205 requires 10 fc, whereas IESNA is 1 fc. IECC, which is based on IESNA lighting values, has a LPD of 0.3 w/sf for parking garage lighting. How do you meet that with lighting levels 10 times as high as the energy code is expecting?

Back to the definitions again

OCCUPIABLE SPACE. A room or enclosed space designed for human occupancy in which individuals congregate for amusement, educational or similar purposes or in which occupants are engaged at labor, and which is equipped with means of egress and light and ventilation facilities meeting the requirements of this code.

A parking garage by its very nature is not designed as an occupiable space therefore I believe you are correct that the minimum lighting requirements of 1205 would not be applicable. Section 1006.2 Illumination level would be appropriate for a parking garage to illuminate the pedestrian traffic areas.

Section 1006.2. The means of egress illumination level shall not be less than 1 foot-candle (11 lux) at the walking surface.

 

[Papio Bldg Dept]

The minimum ceiling heights of Chapter 10 do not apply to parking garages pedestrian traffic areas.

Would this include stairways?

 

[mark handler]

The minimum ceiling heights of Chapter 10 do not apply to parking garages pedestrian traffic areas.

406.3.8 Means of egress. Where persons other than parking attendants are permitted, open parking garages shall meet the means of egress requirements of Chapter 10.

 

[mark handler]

Exactly the point Mark. If the drive lanes are the means of egress access to the stairs in a public garage, is 7 foot or 7'-6" required.

You do have a point, there is a fuzzy area.

 

[mtlogcabin]

406.3.8 Means of egress. Where persons other than parking attendants are permitted, open parking garages shall meet the means of egress requirements of Chapter 10.

1003.2 Ceiling height.

The means of egress shall have a ceiling height of not less than 7 feet 6 inches (2286 mm).

Exceptions:

7. The clear height of floor levels in vehicular and pedestrian traffic areas in parking garages in accordance with Section 406.2.2.

 

[mark handler]

You got it, the exception is the rule.....

 

[mtlogcabin]

Would this include stairways?

1009.2 Headroom.

Stairways shall have a minimum headroom clearance of 80 inches (2032 mm) measured vertically from a line connecting the edge of the nosings .

That is less than 7 feet or 84 inches required by 406.2.2

 

[gbhammer]

mt you the BO. :grin:

 

[Papio Bldg Dept]

1009.2 Headroom.Stairways shall have a minimum headroom clearance of 80 inches (2032 mm) measured vertically from a line connecting the edge of the nosings .

That is less than 7 feet or 84 inches required by 406.2.2

I am working from the 2006 IBC (and I assume everyone else is working from the 2009 IBC). In which case, 1003.2 does not have an Exception 7, so I am assuming I am still in a greyish fuzzy area, where the lack of exception maintains the rule.

Do you uphold the 7' minimum at the landings for enclosed stairways (or any accessory areas) as a continuation/extension of the pedestrian traffic way in a parking garage? This would seem to make sense as a continuation of that floor level. Without that exception am I stuck at 7'-6"?

 

[mtlogcabin]

so I am assuming I am still in a greyish fuzzy area, where the lack of exception maintains the rule.

I don't believe you are in a "grey fuzzy area". 2009 1003.2 Exception 7 just clarifies what is already stated the 2006 Section 406.2.2 and that is 7 foot clear height is all that is required for pedestrian traffic areas in a parking garage.

401.1 Detailed use and occupancy requirements.

In addition to the occupancy and construction requirements in this code, the provisions of this chapter apply to the special uses and occupancies described herein.

 

[Papio Bldg Dept]

I don't believe you are in a "grey fuzzy area". 2009 1003.2 Exception 7 just clarifies what is already stated the 2006 Section 406.2.2 and that is 7 foot clear height is all that is required for pedestrian traffic areas in a parking garage. 401.1 Detailed use and occupancy requirements.

In addition to the occupancy and construction requirements in this code, the provisions of this chapter apply to the special uses and occupancies described herein.

...and the provisions of this Chapter include 406.3.8 MOE referencing a Chapter 10 without exception for the 7'-6" minimum height. I don't see the out. I understand the out comes in later codes, and I understand the logic behind it, but I don't have it currently as far as I can see.

406.3.8 Means of egress. Where persons other than parking attendants are permitted, open parking garages shall meet the means of egress requirements of Chapter 10.

as I read it, the code is stating:

where no persons other than parking attendants are permitted, open parking garages may have a clear height in pedestrian traffic areas of not less than 7'-0", however when I have other persons there, I must conform to the requirements of Chapter 10 and a clear height not less than 7'-6"

 

[IRONWORKER]

I am designing a garage, and trying to achieve natural ventilation. I think I have achieved the required 20% open, as well as 40% perimeter open as per IBC 2006, but what if your garage is really deep? It seems like if you have a very large garage, if you're 150' from the perimeter, air is not likely getting in to the inside of the garage. Is there any requirements, i.e. maximum distance to perimeter opening req'd before needing to implement mechanical ventilation?

Per 2006 IBC:

Depending on size and use: Refer to section 406, IBC;

Open perimeter: Has nothing to do with natural ventilation, but with area increase per section 506, IBC;

Natural ventilation: Refer to section 1203, IBC;

Fire separation distance and fire rating: Refer to Table 602, IBC and to 704.5, IBC;

Maximum area of exterior wall openings based on fire separation distance: Refer to Table 704.8;

If it is a repair garage: Refer to section 403 and Table 403.3, IMC and to section 404, IMC;

If it is a residential garage: Refer to the IRC.

 

[mtlogcabin]

1003.1 Applicability.

The general requirements specified in Sections 1003 through 1013 shall apply to all three elements of the means of egress system, in addition to those specific requirements for the exit access, the exit and the exit discharge detailed elsewhere in this chapter.

Clear height is defined under 406.2.2. Stairs, handrails, emergency illumination and other items not specifically addressed in Chapter 4 would be addressed by Chapter 10

as directed by Section 406.3.8

 

[Papio Bldg Dept]

Per 2006 IBC:Natural ventilation: Refer to section 1203, IBC;

Following this code reference, we would then have an occupied building/space with a minimum open(able) area to the outdoors of at least 4% of the floor area being ventilated. Is that the correct analysis? Would this then limit the area of the building if only naturally ventilated?

 

[IRONWORKER]

Following this code reference, we would then have an occupied building/space with a minimum open(able) area to the outdoors of at least 4% of the floor area being ventilated. Is that the correct analysis? Would this then limit the area of the building if only naturally ventilated?

Yes. I realize that the commentary is not the code, but the commentary does shine light on your question to 1203.4.1: When inadequate natural ventilation is provided, mechanical ventilation can supplement any inadequacy (see chapter 4 of the IMC).

Again, I am assuming that this is not a repair garage.

 

[Papio Bldg Dept]

1003.1 Applicability.The general requirements specified in Sections 1003 through 1013 shall apply to all three elements of the means of egress system, in addition to those specific requirements for the exit access, the exit and the exit discharge detailed elsewhere in this chapter.

Clear height is defined under 406.2.2. Stairs, handrails, emergency illumination and other items not specifically addressed in Chapter 4 would be addressed by Chapter 10

as directed by Section 406.3.8

I see what you are saying now, and after reading the commentary, regardless of how much I dislike the commentary, it is supportive of your position (specific requirements first), and appears that the amendments in the 2009 IBC were to clarify or delineate which comes first. In other words, the commentary says, Section 406 super-cedes Chapter 10 to address elements not contained in Section 406. It also states that parking garages are not occupied (not sure I agree with the commentary here, but I am tired of questioning the little grey fuzzy areas of the code today), and the percentage of openings specified in 406.3.3.1 is the only requirement for ventilation (getting back to the OP), and no mechanical ventilation systems are required.Thanks MT (and everyone else) for being patient with me today.

 

[IRONWORKER]

Following this code reference, we would then have an occupied building/space with a minimum open(able) area to the outdoors of at least 4% of the floor area being ventilated. Is that the correct analysis? Would this then limit the area of the building if only naturally ventilated?

I hope you realize that the area and use of a commercial building is set by Table 503, allowable area increases (506), fire areas and sprinkler requirements Chapter 9.

 

[Papio Bldg Dept]

I hope you realize that the area and use of a commercial building is set by Table 503, allowable area increases (506), fire areas and sprinkler requirements Chapter 9.

Yes, thank you. I was simply wondering, if 1203.4 were applicable to open parking garages (which it appears it is not), if the 4% floor area requirements would prove more restrictive for a 7' floor to ceiling clear height than the Chapter 5 Tables and Increases. Just another one of my (il)logical tangents down the path of code curiosity that that killed the code cat.