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Access to flat roof on 1 story commercial building

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palikona

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The flat roof I am designing for a 1 story commercial building is 15' above grade. In some places, the roof edge is visible and has a gutter there, and in other locations, there is a parapet that goes up to 16'. For some reason, I thought there was a IBC or OSHA section that allows for roof access to come from a movable ladder (not permanent) and not from a roof hatch. However, now I cannot find those sections anywhere. Does that sound right?
The building is a 10,000 sf footprint, with all of the mechanical equipment hidden behind a screenwall @ the middle portion of the footprint. Would it be a smarter design to provide for a roof hatch within that mechanical yard location, vs a more passive strategy of just saying the owner or workers can access the roof from numerous locations around the building with a movable ladder?
 
palikona said:
So if I read that correctly, I am ok to have the roof accessible by portable ladder since it's 15'?
Click to expand...
Your understanding is confirmed in the first paragraph of this document:


This is based on the 2015 International Mechanical Code so you’ll want to confirm if any changes have been made to this.

palikona said:
However, would it be smarter to provide the roof access far from the roof edge, by the mech yard? I'm thinking yes?
Click to expand...
If your intuition is telling you that it’s better to move the roof access away from the roof edge then that’s probably what you should do.

Over 15 years ago I took an OSHA safety class where the instructor said the largest cause of construction site injuries (maybe they said fatalities?) involved ladders. Here’s an article giving some statistics related to fatalities and injuries involving ladders:

www.bls.gov

Fatal injuries from ladders down in 2020; nonfatal ladder injuries were essentially unchanged

In 2020, there were 161 fatal work injuries from which ladders were the primary source. This was a 5.8-percent decline from 2019. Nonfatal ladder injuries resulting in at least one day away from work were essentially unchanged in 2020.
www.bls.gov www.bls.gov

In the second chart it says that installation, maintenance, and repair is the biggest group of non-fatal ladder accidents.

I don’t know what kind of OSHA requirements you’ll have, I assume there’s something about attachment points for fall protection.
 
palikona said:
Thank you. So if I read that correctly, I am ok to have the roof accessible by portable ladder since it's 15'?

However, would it be smarter to provide the roof access far from the roof edge, by the mech yard? I'm thinking yes?
Click to expand...
You should be okay at minimum to not install a fixed ladder. I've worked on a few one-story projects recently where we didn't install a built-in ladder.

That said, it's typically far, FAR safer, quicker/more efficient (to access the roof after construction is complete), and just all around better practice to have a built-in ladder if possible. The only reason we didn't install a ladder on those projects was because of the owners refusal due to security concerns. We tried to get them to change their minds...
 
An extension ladder has fatter rungs which are easier on the feet. Climbing an incline is less strenuous than climbing straight up a wall. I prefer an extension ladder even when there is a permanent ladder.
 
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walker.t said:
Your understanding is confirmed in the first paragraph of this document:


This is based on the 2015 International Mechanical Code so you’ll want to confirm if any changes have been made to this.


If your intuition is telling you that it’s better to move the roof access away from the roof edge then that’s probably what you should do.

Over 15 years ago I took an OSHA safety class where the instructor said the largest cause of construction site injuries (maybe they said fatalities?) involved ladders. Here’s an article giving some statistics related to fatalities and injuries involving ladders:

www.bls.gov

Fatal injuries from ladders down in 2020; nonfatal ladder injuries were essentially unchanged

In 2020, there were 161 fatal work injuries from which ladders were the primary source. This was a 5.8-percent decline from 2019. Nonfatal ladder injuries resulting in at least one day away from work were essentially unchanged in 2020.
www.bls.gov www.bls.gov

In the second chart it says that installation, maintenance, and repair is the biggest group of non-fatal ladder accidents.

I don’t know what kind of OSHA requirements you’ll have, I assume there’s something about attachment points for fall protection.
Click to expand...
I've been trying to find OSHA dimensional requirements for roof access hatches that are utilized solely for roof maintenance and rooftop equipment maintenance, not required by CBC / IBC chapter 10.
A google image search shows hatch dimensions like this:
1738865006767.png

7" to ladder rungs + 30" to back of hatch = 37" minimum hatch opening.
However, I can think of hundreds of buildings that have 30" hatches. Major manufacturers such as Bilco tell me their most popular hatch size is 30" x30".
How can that be? Does the ladder not need to extend up into the hatch? Did google not accurately portray OSHA requirements?
 
Yikes said:
7" to ladder rungs + 30" to back of hatch = 37" minimum hatch opening.
Click to expand...
Second page of this PDF says 37” is the minimum which matches your calculation.


Yikes said:
Major manufacturers such as Bilco tell me their most popular hatch size is 30" x30".
Click to expand...
The PDF linked above shows it extending into the hatch, I looked briefly on the OSHA site and couldn’t find a provision addressing the top of ladders at roof hatches.

Yikes said:
Did google not accurately portray OSHA requirements?
Click to expand...
It appears to be correct, same image is on the OSHA site:

 
ICE said:
An extension ladder has fatter rungs which are easier on the feet. Climbing an incline is less strenuous than climbing straight up a wall. I prefer an extension ladder even when there is a permanent ladder.
Click to expand...
Also, the fixed ladders do not extend above the hatch and there is nothing to grab to get though the hatch. while an extension ladder can extend above the roof and makes it a lot safer for an old guy like me to step from the ladder to the roof.
 
Mr. Inspector said:
Also, the fixed ladders do not extend above the hatch and there is nothing to grab to get though the hatch. while an extension ladder can extend above the roof and makes it a lot safer for an old guy like me to step from the ladder to the roof.
Click to expand...
The fixed ladder needs to extend above the roof:

1738875622835.png
 
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Conceptually it would look something like this, with a side-step out of the hatch:

1738877662957.png

Because the height difference is less than 16', we don't need the extension above the hatch, but I assume we need the ladder to go into the "shaft" area below the hatch.
 
ICE said:
I disagree. Dismounting the ladder is no less dangerous whether it be 12’ or 16’.
Click to expand...
You are correct. I misstated. I should have said, when the vertical climb is less than 16 feet, I don't need and permanent means of access to the roof at all.
1738880610918.png

If I don't need the hatch as a "required access", then even if a hatch is installed anyway, an extension is still not part of a "required access" (but may be best practice nonetheless).
 
If a permanent ladder is installed I would ask that all of the code that applies to a permanent ladder be followed. Without looking at the code book, I assume that the extension is part of the requirements.
 
This from the reason statement to the 2024 IMC. The item#1 it refers to is the extension in question. Reading OSHA 1910.23, it refers to all ladders, which I would take to mean "provided", whether required or not. Item #1 is identical in OSHA.

1738947005895.png
 
304.3.1 Access. Buildings exceeding 15 feet in height shall have an inside means of access to the roof unless other means acceptable to the Authority Having Jurisdiction are used.

304.3.1.1 Access Type. The inside means of access shall be a permanent, or foldaway inside stairway or ladder, terminating in an enclosure, scuttle, or trap door. Such scuttles or trap doors shall be not less than 22 inches by 24 inches in size, shall open easily and safely under all conditions, especially snow; and shall be constructed so as to permit access from the roof side unless deliberately locked on the inside.

304.3.1.2 Permanent Ladders. Permanent ladders required by Section 304.3. L1 shall be constructed in accordance with the following:
(1) Have side railings which extend not less than 30inches above the roof or parapet wall. (2) Landings shall not exceed 18 feet apart measured from the finished grade.
(3) Width shall be not less than 14 inches on center.
(4) Rungs shall not exceed 14 inches on center.
(5) Toe space shall be not less than 6 inches.

Code requires that rooftop equipment be accessible.
Building exceeding 15 feet in height require an inside access. The inside means of access can be a permanent ladder or stairs.
A building that does not exceed 15 feet in height does not require an inside means of access however, a means of access is still required, but not by Section 304.3.1.1

The essence of the argument is that only permanent ladders that are required by Section 304.3.1.1 must meet code Section 304.3.1.2, A conundrum arises with the proviso that ladder side railings shall extend not less than 30 inches above a parapet wall, Clearly that indicates that Section 304.3.1.2 also applies to exterior ladders. It is therefor not a leap to suggest that Section 304.3.1.2 applies to all permanent ladders.

But then there are those that refuse to leap and given the intentional nature of the wording that makes it clear that the construction requirements of a ladder do not apply universally. The saving grace is this portion of a sentence: "unless other means acceptable to the Authority Having Jurisdiction are used." Now you can stack orange crates.
 
ICE said:
304.3.1.1 Access Type. The inside means of access shall be a permanent, or foldaway inside stairway or ladder, terminating in an enclosure, scuttle, or trap door. Such scuttles or trap doors shall be not less than 22 inches by 24 inches in size, shall open easily and safely under all conditions, especially snow; and shall be constructed so as to permit access from the roof side unless deliberately locked on the inside.

304.3.1.2 Permanent Ladders. Permanent ladders required by Section 304.3. L1 shall be constructed in accordance with the following:
(1) Have side railings which extend not less than 30inches above the roof or parapet wall. (2) Landings shall not exceed 18 feet apart measured from the finished grade.
(3) Width shall be not less than 14 inches on center.
(4) Rungs shall not exceed 14 inches on center.
(5) Toe space shall be not less than 6 inches.
Click to expand...

Sifu said:
This from the reason statement to the 2024 IMC. The item#1 it refers to is the extension in question. Reading OSHA 1910.23, it refers to all ladders, which I would take to mean "provided", whether required or not. Item #1 is identical in OSHA.

View attachment 15110
Click to expand...

Current IMC roof ladder access requirements are here: https://up.codes/viewer/maryland/imc-2021/chapter/3/general-regulations#306.5
Current UMC (CMC) roof ladder access requirements are here: https://up.codes/viewer/california/ca-mechanical-code-2022-1/chapter/3/general-regulations#304.3.1
2024 UMC is here: https://epubs.iapmo.org/2024/UMC/

In both cases, the hatch clearance requirements are much smaller than what OSHA is requiring. The UMC/CMC requires a 22" wide x 24" deep hatch, with rungs min. 6" away from the wall. OSHA appears to require at least 24" wide x 37" deep, with rungs min. 7" away from the wall.
The plan checkers are only enforcing the IMC and UMC.
Sifu, why would IAPMO comment that it's time to revise the code, refence the OSHA standards, then allow a minimum hatch size that is smaller than what OSHA requires?
And if OSHA really does require at least 24"x37", why don't the major hatch manufacturers such as Bilco or Babcock Davis have something reasonably close to that size (maybe 24x42 or 30x42) as a standard available item? The closest they get is 30x54 or 48x48.

I'm wondering if for years I've been specifying 30x30 hatches that were passed by all inspectors yet may run afoul of OSHA.
 

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OK, I just talked to the sales rep for Babcock Davis, a midwest roof hatch manufacturer, and got a straight answer.
He says that 75% of their business is 30" x 36" roof hatches, because is complies with the mechanical codes; and most design firms don't seem to pay attention to OSHA.
Those that do pay attention to OSHA are ordering 48"x48" hatches. This helps not only with OSHA compliance, but also with moving tools and replacement parts up to the roof, especially given the increase over the years in rooftop components such as solar PV, satellite dishes and antennas, etc.

Basically, he's telling designers at lunch-and-learns that best practice is at least 48x48 if we have the room for it.
 
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