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Strength of a hand/guard rail

Strength of a hand/guard rail

New postby Nathan51 on Mon Nov 16, 2009 9:02 pm

My inspector call me on a handrail that only had 3 support brackets and said I needed more to support 250 pounds anywhere on the rail with a force at any direction. I can't find anywhere in the o6 IRC that talkes about what the matterial has to be or strength of matterial. Is there anything that says anything about how many pounds a handrail or guard rail has to be able to support in any direction?
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Re: Strength of a hand/guard rail

New postby Jerry Peck - Codeman on Mon Nov 16, 2009 10:33 pm

Nathan,

Your inspector is correct, except that the weight for handrails is 200 pounds and not 250 pounds.

The *handrail* is required to support ('resist' is a better word) a load of 200 pounds at any point along the handrail applied in any direction.

This also only makes logical sense as the handrail is provided there to allow people to grasp and hold it so they do not fall, and that includes the average person, which is applied as 200 pounds, and that person grabbing the handrail will grab it and exert their theoretical 200 pound weight in whatever direction they may be falling, thus the 'in any direction' part.

Now, guardrails are different.

First, if the handrail is mounted to a guardrail, then naturally the guardrail would need to support the handrail which is resisting that 200 pound load in any direction. The top rail of the guardrail is required to be able to resist the same load as a handrail as that is what the person would be grasping if there is no handrail there, and maybe even with a handrail there.

Second, the in-fill panel of the guardrail needs to be able to resist a person or child falling against the in-fill panel of the guardrail and keep that person or child from falling through. That load is 50 pounds per square foot of the in-fill panel - including air. I.e., the open space are expected to resist that same 50 pound pounds per square foot, but as we all know that the air will not support any weight like that, the in-fill panel which surrounds and includes the air within that one square foot area must be strong enough to resist that 50 pounds per square foot.

Think of it this way: You fall against the guard and its in-fill panel, you hit between two balusters, those two balusters, and their attachment at the top and bottom, must resist at least 50 pounds for a one square foot area, which will, unless the in-fill panel is solid, include some air due to the openings in the guard.

Refer to Table R301.5 in the IRC.
- Table R301.5
- - Minimum Uniformly Distributed Live Loads
- - - (in pounds per square foot)
- - - - - - - - - Use_______________________Live Load
- - - - Guardrails and handrails d___________ 200 i
- - - - Guardrail in-fill components f_________ 50 i
- - - - note d: A single concentrated load applied in any direction at any point along the top.
- - - - note f: Guard in-fill components (all those except the handrail), balusters and panel fillers shall be designed to withstand a horizontally applied normal load of 50 pounds on an area equal to 1 square foot. This load need not be assumed to act concurrently with any other live load requirement.
- - - - note i: Glazing used in handrail assemblies and guards shall be designed with a safety factor of 4. The safety factor shall be applied to each of the concentrated loads applied to the top of the rail, and to the load on the in-fill components. These loads shall be determined independent of one another, and loads are assumed not to occur with any other live load.

Thus, your inspector needs to change his 250 pounds to 200 pounds, and both the top of the guardrail and the handrail need to be able to support and resist that 200 pounds applied at any location and applied in any direction (which also includes up).

The in-fill panel only needs to be able to support and resist 50 pounds per square foot applied horizontally any where in the in-fill panel.
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