History of 200lb Railing Load 1

[bookowski]

Anyone know the origin of railing loads? I found the 200lb requirement in the 1968 building NYC code but not earlier NYC codes. Any info on where/when it originated and the source of 200lbs?

 

[mtu1972]

Don't know the origin of the load, but I do know that in the mid '70's it was measured against failure, not allowable stress (now strength). Working on MN's Iron Range, we switched from pipe posts/rails as the Pipefitters were claiming all "pipes" on the projects. We used flat bars for the posts and solid rods for the rails and had to build and load test an assembly to insure that it would not fail.

gjc

 

[racookpe1978]

Like a lot of Codes, there is little logic involved, and many thumb rules that get "codified and glorified" in stone.

Assume 50 lb/foot sideways load at the top of the railing (then at the 3 ft - 6 inch limit), and a 4 ft interval between posts. presto! 200 lbs sideways force on each post. That then gets written up as a limit for the rail.

But there really has never been a "measurement" justifying why 50 lb/ft is a proper design rule either.

 

[DBronson]

bookowski:

It looks like it came from this publication:

American Standard Safety Code for Floor and Wall Openings, Railings and Toe
Boards, ASA A12-1932.2

"The anchoring of posts and framing of members for
railings of all types shall be of such construction that the
completed structure shall be capable of withstanding a
load of at least 200 pounds applied in any direction at any
point of the top rail. [Section 7.3(d)]"

Where the ASA got it is anyone's guess.

Regards,

DBronson

 

[bookowski]

Thanks DBronson

 

[Bagman2524]

The earliest document I can find that addresses design loads is "Minimum Live Loads Allowable for Use in Design of Buildings", 1924 by the National Bureau of Standards. I believe its the precursor to ANSI A58.1 - ASCE-7, Minimum Design Loads for Buildings and Other Structures. I don't see any mention of railing loads in the NBS document though, so the ASA A12-1932.2 mentioned above must be the earliest.

Faith is taking the first step even when you can't see the whole staircase. -MLK

 

[bookowski]

DBronson's reference is the earliest that I've found as well. I checked 1922 and 1938 NYC Building codes and it doesn't appear in those. It would be interesting to know where that number came from. (Became curious about this because an architect informed me that 'this must be a new thing' when I told him his railing detail looked suspect and informed him of the requirement)

 

[bridgebuster]

bookowski - the 1900 NYC Code says railings must be "...strong enough..."

 

[TehMightyEngineer]

"Don't do bad things, only do good things..."

Maine EIT, Civil/Structural.

 

[Bagman2524]

ANSI 1264.1 section 5.6.1 also has the 200 lbs. rail load. But it's later than the ASA A12. The NBS document references 109 other local building codes. I suppose the local building codes pre-dated the national ones, with NYC being the oldest??

Faith is taking the first step even when you can't see the whole staircase. -MLK