Minimum Manway Size 1

[esass13]

Does anyone know of a required size of a manway on a hydro-tank? A requirement by OSHA or ASME or anyone? I can't seem to find one anywhere.

I know you can't go too small, but I'm trying to justify (other than good sense) why we should use a larger standard manway for our tanks.

Thanks

 

[doct9960]

Check first with the local jurisdiction.

For ASME VIII Div. 1 vessel, refer to UG-46.

For ASME VIII Div. 2 vessel, refer to AD-1020.

 

[JStephen]

It's not uncommon for hydropneumatic tanks to use the same size manways as on adjacent ground storage tanks, which will mean 24" or 30" or so, although you'd be hard put to justify this practice. The larger manways on ground storage tanks are partly to get scaffold pieces through.

A worker with necessary safety gear needs to be able to get in and out for painting operations, and that would set the minimum size.

 

[arto]

MIL-HDBK-759 & ASTM F1166 list "Human Factors" Dimensions.
Also Woodson's "Human Factors Design Handbook"

 

[deanc]

The Code specs. sizes. doct9960 is correct.You can buy these per made and to Code.

I like a nice "large" one....was inside a mud drum once with a guy who panicked stuck in the only manway out. By the time we got his coveralls and belt removed,two guys pulling outside and me pushing inside,none of us were real happy.

 

[davefitz]

Osha rules for sites that have women workers may require a larger dia manway than defined by ASME.

 

[dtn6770]

davefitz,

At the risk of starting a thread tangent, I've gotta ask...why would OSHA think women workers need larger manways? I can only imagine the spectrum of repsonses people could offer.

 

[handleman]

I'm guessing it may have to do with squeezing past another person... less "incidental" contact required.

 

[JStephen]

If it's a 12x16 or 14x18 manway, nobody is squeezing past anybody. And on just about any manway, you're going to have some people that can get through it and some that can't (not just from manway size, but configuration and height off the ground as well).

 

[davefitz]

I recall from 20 yrs ago, that a chemical refinery in Houston was required to replace manways with larger manways due to the issu of larger-hipped women not being able to be safely evacuated thru the smaller manways. I do not recall if it was a direct OSHA rule or implied due to a lawsuit alleging lost workplace opportunities because women would not be permitted to be promoted to certain jobs that required access thru smaller manways.

 

[arto]

How'd the "larger hipped" persons get inside in the first place.
If you got in through the manway, shouldn't you be able to get out through the same sized opening?
[unless maybe it's a vat of beer or a tank of doughnuts ;-)]

 

[GenB]

I was thinking on the women upper body then you guys cahnged to hips!

 

[sbush]

The "Recommended Standards For Water Works" (a.k.a. The Ten State Standards), a report of the Committee of the Great Lakes--Upper Mississippi River Board of State Public Health and Environmental Managers, states under the category of hydropneumatic tanks that "where practical the access manhole should be 24 inches in diameter". Although the "Ten States Standards" is not specifically enforced by government regulation or law, many states have adopted language from them to write their own standards and regulations for public water supplies.

S. Bush

http://www.water-eg.com

 

[unclesyd]

All aside, you need to stay with a 24" if possible. If you drop down in size to 20" or even a an 18" remember that the nozzle neck needs to be shortened as the size decreases.
Just remember that management will want you to go through anything that you can get your head and one arm through.

The newer 17" oval manways for boilers are 100% better than the 16".

We require a 24" manway in all our vessels for safety reasons. The biggest concern is getting a stretcher or back board through the manway.

Case in point.
This requirement just paid for itself in spades during a recent turnaround where a contract employee had entered a 40' high reactor through a top 24" manway and as he got to the bottom he slipped on the bottom head and impelled himself on a thermowell that penetrated the bottom head. If it hadn't been a 24" manway the only other was out was by removing a 24" over flow line which would have required several hours of work.

 

[dugal]

First off, we should refer in future to these as "access flanges" and not "manways". Manways is a thing of the past and not politically correct these days. I have supervised many trades staff of both genders. Believe me, both genders come in all different sizes and shapes. Some are just not suitable for entry into a vessel. They however can be quite able to other work.
Cheers

 

[JStephen]

It's not actually a flange, though, in fact, the elliptical manways don't even have a flange.

As far as I know, the local cities still call a manhole just that.

 

[vic23]

i would like to know what is the minimun size manhole is in a boiler?