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RE: What about iron balusters and guardrails?

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In regards to Williams last statement, the UBC has changed their wording a
bit and now has an exception for "...commercial and industrial-type
occupancies which are not accessible to the public...". (UBC 509.3) which
makes it tougher to invoke the OSHA requirements instead of the UBC
requirements for those "gray" areas.

Thomas Hunt
Duke/Fluor Daniel

---------------------- Forwarded by Tom Hunt/DFD on 07/31/2000 05:32 PM
---------------------------


"Sherman, William" <ShermanWC(--nospam--at)cdm.com> on 07/31/2000 04:40:23 PM

Please respond to seaint(--nospam--at)seaint.org

To:   "'seaint(--nospam--at)seaint.org'" <seaint(--nospam--at)seaint.org>
cc:

Subject:  RE: What about iron balusters and guardrails?


In general I agree with Mark's description of guardrails and handrails,
except that I think that the top rail of guardrails should generally act
similar to handrails, based on OSHA (as it applies to "all permanent places
of employment"). Below I have added some comments related to these
requirements:

OSHA also refers to "guardrail" as "railing" to act as a vertical barrier
and states "The top member of railing usually serves as a handrail". A
"standard railing" is generally required to prevent hazards due to falling
and may also be used at open sides of stairs. For a standard railing "The
top rail shall be smooth-surfaced throughout the length of the railing." (I
would apply this adjacent to various types of walking surfaces, even if not
a stair.) The structural design of railings of all types requires design
for
a 200 lb load applied in any direction at any point on the top rail. OSHA
railings only require a top rail and an intermediate rail (i.e. for
railings
at equipment platforms, tanks, etc).

One difficult question is "When is an OSHA railing required and when is a
building code approved guardrail required?" Some locations are obvious but
there are many locations which are not so obvious, such as: inside an
equipment building which is not normally occupied; equipment floors within
an occupied building but at a lower level which is not regularly accessed;
exterior walkways, which are not directly part of an egress; etc.

> -----Original Message-----
> From: Swingle, Mark [mailto:Mark.Swingle(--nospam--at)dcp.state.ma.us]
> Sent: Monday, July 31, 2000 2:49 PM
> To: 'seaint(--nospam--at)seaint.org'
> Cc: 'mswingle(--nospam--at)earthlink.net'
> Subject: Re: What about iron balusters and guardrails?
>
>
> Re: Guardrails and Handrails
>
> This is a topic that is not too complicated, but is seldom
> well-understood
> by structural engineers (at their peril).
>
> Guardrails and handrails are two different items, which have
> two different
> sets of structural design requirements.  Different codes vary
> somewhat in
> the specific forces, but the concepts are all similar.
>
> GUARDRAILS are required where there is a sudden change in
> elevation greater
> than 30" (typical value).  Examples are balconies, decks,
> retaining walls
> (if there is a walkway along the top), mezzanines, and the
> open sides of
> stairs.  (The three exceptions I know of are the audience
> side of a stage,
> trap doors in stages, and loading docks.  Try to imagine these with a
> guardrail....)
>
> There are two distinct components of the guardrail: the top
> rail, and the
> portion between the floor and the top rail, where the
> balusters go (or maybe
> it is solid).  The top rail of the guardrail is not the same
> as a handrail,
> except in special circumstances (see below).  The "top rail"
> may not even be
> a rail in the true sense.  Picture a solid glass guard with
> an integral rail
> at the top.
>
> There are architectural requirements with respect to the
> minimum height of
> the top rail of the guardrail and the maximum size sphere that can fit
> through the spaces in the baluster system (typical is 42"
> high for top rail
> (36" for some residential) and a max 4" sphere through the
> spaces).  There
> are NO requirements for grippability of the "top rail",
> unless it is ALSO a
> handrail (see below).
>
> There are structural design requirements for the capacity of
> the top rail
> and the baluster portion to resist applied loads.  Typical is
> a concentrated
> load applied in any direction to the top of the guardrail, OR
> a uniform
> (line) load horizontally to the top of the guardrail, and a
> uniform (areal)
> load on the entire baluster section.  Typical for UBC is EACH of the
> following, considered INDEPENDENTLY: 20 plf (residential) or
> 50 plf (all
> others) on the top of the guardrail;  200 lbs in any
> direction on the top
> rail; and 25 psf on the balusters.
>
> HANDRAILS are required on stairs and ramps for gripping with the hand.
>
> There are architectural requirements with respect to location
> and size of
> handrails:  whether one or both sides of stairway (or ramp);
> height above
> ramp or nosing of stair treads, distance from wall, min and
> max sizes of
> grip, and extensions beyond the end of stair or ramp.
> Typical are between
> 34" and 38" above nosing (to center), 1.5" min space, 1.25"
> min and 2" (?)
> max diameter, 12" extensions (except residential stairs).
> Residential only
> requires handrail one side (?), commercial two sides plus intermediate
> handrails where stairs are wider than 88" (?) etc.
>
> There are structural design requirements for the capacity of
> the handrail to
> resist applied loads.  Typical is a simultaneous horiz and
> vert concentrated
> load at any point along the rail, 50 lbs each per Scott (?).
>
> In some cases, the top rail of the guardrail and the handrail
> are the same
> thing.  This occurs on some residential stairs where the architectural
> requirements allow the guardrail height to be the same as the handrail
> height.
>
> My 2 cents.  I invite corrections, arguments, and criticism.
>
> Mark Swingle
>
> ------------------
>
> On 29 July 00 Francisco Duarte wrote:
>
> <do we need to design the iron balusters and railing systems?
> If so where do
> we get info in terms allowable values.
> Are there any text books that have pretty much standard
> construction details
> for different kinds of railing and guardrail systems.
>
> <Same thing goes for stairs.
> any comments will be appreciated
>
> <Mil Gracias,
> <(thank you)
>
> <F.D. (E.I.T)
>





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