Choosing the right size tube for handrailing

[stupenny]

Hi,
As the title suggests i need to know how you work out the correct size tube for a handrail. I have an access platform with 33.7o/d tubing the client is asking if this meets British Standards, BS 5395-3 say the tube should withstand a lateral load of 0.36kN/m and that's pretty much it. Is there a way of connecting the BS1387 tube used with the BS 5395-3?

Thanks in advance.

 

[SteelPE]

I'm not familiar with the British Standards but how hard could it possibly be. Here in the US a handrail is required to be a certain size and resist a certain load, I think it's 50 plf (note the guardrails are required to resist 50plf or a 200# concentrated load). Basically you figure out the maximum moment the section can take and then space your supports so that the moment in the systems never gets above that moment. If I remember correctly, it usually works out so that we end up with supports at around 4'-0" o.c.

 

[Bagman2524]

SteelPE is correct. The design load in the US per the IBC code is 50 plf or 200 lbs. concentrated load. I think OHSA only requires a 200 lbs. concentrated design load. 33.7 mm and 0.36 kN/m converts to 1.33 inches and 25 plf in English units. Seems the British Standards are more lenient. IBC requires a min 1.25 inch outside diameter handrail (and a max. of 2 inch); however OHSA has no size requirements. 1-1/4" schedule 40 is the most common size used to meet the load and diameter requirements.

 

[EngineeringEric]

I would start and usually end with 1.5" steel pipe, (1.9" OD) for the rail and posts. The posts go at 4' o.c. to make the 50plf equal 200# concentrated. The important part to consider is the attachment of the posts to the walkway. Since this is an access platform i will assume steel channel stringers, therefore i would use double angle clips welded to each post-to-web.

Obviously post heights, obstructions, attachments, and other details may effect the design but this is typically a good base point to start.