OSHA Handrail (top rail) 200lb exac

[Cassidy G]

OSHA Handrail (top rail) 200lb exact location.

Hi! Good day Engineers.

I am design a OSHA stairs with handrail. I'm confused about 200lb concentrated live load, downward or outward direction.


For example top rail length is 25ft. I am planning to distribute the 200lb over the total length of top rail. And it becomes 8lb/ft acting in the top rail total length.

Can anyone give me advice.

Thank you.

 

[dik]

I suspect he's smarter than that... just pointing the way forward... to produce a safe, easy, and economical design...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[jayrod12]

Where I practice, all commercial, industrial and multi tenant residential stairs are designed for 100 psf live load. Which on a 5x10 platform would equal 5000lbs total.

What is the application of the stair? Does it fall under Oshawa the local building code? If it's an egress stair, I believe it would need to comply with both.

 

[phamENG]

It it's egress, I'd design for 100spf. If it's not an egress stair, and only provides access to a small platform or piece of machinery for maintenance (some sort of typically unoccupied area), I'd use 40 psf as a "catwalk for maintenance access."

And I always combine handrail loads with floor loads for this kind of structure. For somebody to apply the load on the handrail, they must naturally be standing on the platform. Unless they're falling from a higher one, but I don't think that's quite a condition the code contemplates.

 

[r13]

I remember, in the old time, there is a concentrate load requirement. For industry settings, it can govern, if required.

 

[phamENG]

For maintenance catwalks it's a minimum 300# point load, higher if you know the future use sufficiently and know that some piece of equipment will load it more.

 

[Cassidy G]

Hi Engineers

It is OSHA stairs, for industrial and warehouse.



That 100psf is for IBC stairway, but the code says,

(It should be noted that factory, industrial and storage
occupancies in areas that are not accessible to the public and
that serve an occupant load not greater than 50 are excluded
from the uniform live load for guards. Refer to ASCE/SEI 7,
Section 4.5.1.)

 

[Cassidy G]

For OSHA stairs

Five times the normal live load or minimum of 1000lb.

The code give an example.

(For example, a 3-ft-wide stair with nine treads is used to
access an equipment platform by one worker weighing 300
lb (including tools). The total live load is 300 lb over approx-
imately 27 ft2
. The uniform load is then (300 lb)/(27 ft2
) =
11.2 psf. Per OSHA, this is the normal live load. The stair
should be designed for five times this value or 56 psf.)

But if you check the load that the 1 tread will carry it is only 168 lb.

 

[Cassidy G]

I'm designing a stairway for industrial and warehouse.

The stairs are outside the structure. And it's like overhang stairway.

 

[r13]

1910.25(b)(6)

Each stair can support at least five times the normal anticipated live load, but never less than a concentrated load of 1,000 pounds (454 kg) applied at any point;

I hope this provision clears your concern.

 

[Cassidy G]

r13

Yes Sir I already read that. Meaning each stair tread should resist at least 1000lb concentrated load.

But I only thinking about the example given by the code.

 

[Cassidy G]

For examle each stair tread has dimension of 2.79ft x .82ft. Using the 1000lbs min.

Each tread should resist 437.1 psf?

Which quite large compared with IBC 100psf. That 100psf is for public use.

 

[r13]

The thread shall be able to support 5*100= 500 psf uniform load, or a 1000 lbs concentrate load. Does this make sense?

 

[Cassidy G]

https://www.osha.gov/laws-regs/standardinterpretations/2000-05-08-0

Questions 2 and 3, Sir.

 

[Cassidy G]

Sir, the 100psf is live load for IBC, for public use. I think 100psf should be greater than the live load for industrial stairs (OSHA)

 

[Cassidy G]

Sir jayrod12 and Sir phamENG

100psf is for IBC right?

Or even industrial stairs (OSHA) you used 100psf for stair tread, landings?

 

[r13]

Note the key sentence in this provision is "Fixed stairways shall be designed and constructed to carry a load of five times the normal live load anticipated but never of less strength than to carry safely a moving concentrated load of 1,000 pounds".

For the stair way, as a whole, to achieve the objective to have a strength to carry 5 times of the normal live load anticipated, or a minimum 1000 lbs concentrated load placed anywhere in the stair system, each components (thread, landing, stringer...) must have the same capacity. The IBC specified live load shall be considered the normal live load anticipated, thus, for each component, as well as the entire stair way, a 500 psf live load is to be applied, and compared with the 1000 lbs minimum concentrated load applied anywhere on the components, and the stair system. However, this contradict the example by a mile, where is the example provided, and how the "normal live load" is defined? I agree that we need ti dig little deeper into it.

 

[r13]

Design of stringers, treads, and their connections are left to the structural engineer. Regarding structural design criteria, 2018 IBC Table 1607.1 (30) requires stairs to resist a minimum live load of 300 pounds (concentrated load) or 100 pounds per square foot (psf), or 40 psf for one one-and two-family dwellings.

IBC specifies 300 lbs concentrated live load is less than the OSHA 1000 lbs minimum requirement, so OSHA governs. Then the IBC specifies 100 psf uniform live load, thus per OSHA, 500 psf governs. Hope this helps.

 

[phamENG]

First - please don't call me "Sir phamENG" - I'm flattered, but there hasn't been a knight in my family for over 300 years.

You still haven't clarified the use of this stair. Is it leading from an exit route used for life safety planning? If so, then your "normal live load" needs to be 100psf. If not, then you can use something lower, like 40psf or 50psf.

Based on the clarification statement issued by OSHA that you posted above, the 5x sounds like a safety factor. It specifically says it is for ultimate design and should not be used with AISC's ASD specification (the letter is a bit dated). I would still use the AISC design equations, but be sure to ignore Ω and Φ. Instead, compare your 5xNormal Live Load directly to the result of M[sub]n[/sub], V[sub]n[/sub], etc. It's very important that you understand the codes, how and why they are written the way they are, and what all of the adjustments, factors, etc. mean. If you don't, get with a senior engineer to go over them and help you through this. Swapping out the wrong thing can mess everything up really easily.

The 1000 lbs is applied everywhere, but not all at once. You need to put it in the middle of the tread (not spread over the tread) to check bending in the tread. You need to put it on one stringer, in once place at a time, and develop and enveloped bending moment diagram and shear diagram (and torsion, depending on your design). But you don't have to put them all over the stair all at once. It's to test individual components and ensure their strength and resiliency (uniform loads work well for the overall structure, but don't always capture the little stuff sufficiently).

The guard exemption in ASCE 7 doesn't get you out of the OSHA requirements. ASCE 7 has the 50plf requirement AND the 200# requirement, whereas OSHA only has the 200# point load requirement.

Where is this project located? Looks like you're in the Philippines. I know you guys use several American building codes, but do you all use our OSHA standards, too? Or are you designing a US project?

Hope this helps.

 

[Cassidy G]

Good day, Engineers.

I really appreciate your comments and advice, thank you.

I need some clarification. For example the thread has dimension of 0.850m x 0.250m.

Let say the live load is 500psf or 23.94kPa.

1 thread should resist 518.58 kg. Is it alright. I think it's too heavy.

 

[Cassidy G]

phamENG

The use of stairs is to provide a way or to access different floor levels.

The structure is 6-storey. It is pre-treatment, meaniny every floor has operating equipment.

Is it still 100psf normal load, and become 500psf?