Expert: Sharon Toji - 10/13/2011

Question
Hello,
I have a question regarding handrail glass thickness required for a handrail installed California.
The code says that the glass shall be at least ¼” thick tempered glass, but it seems to use the 1/4 “ as a rule of thumb due to the many possible handrail scenarios and structural variables for the glass supports in a residential handrail, for instance the closer the horizontal  and  vertical supports are the thinner the glass could be and still meet the 4X safety requirements calculations. So it seems that the ¼ dimension is more of a catch all dimension for glass supported on all four sides and not taking any load other than impact.
My problem.
3/16” tempered glass was mistakenly delivered and  installed in a deck handrail, the horizontal glass supports are 31” apart and the vertical supports are 50” apart so the 3/16” glass has an unsupported area of 10.76 square feet per panel. The Building department has told me that if I can show that this works by the calculations set forth in the glazing industry standards and meets the 4X safety calculation that I will not be forced to change the glass. The rails and post all meet the requirements for loading.
Can anyone do the calculation to tell me if the installation above meets the code, or maybe give me some direction.
The standards are in Section II page 41 of the Glazing Industry Standards.
Any help would be greatly appreciated.
Thank You,
Roger


Answer
it sounds as if you have already contacted the Glass Association, which is how I usually direct these questions. They are very helpful. But, if you need an actual calculation done, you may need to hire someone who is qualified to do that. There have got to be engineers who could do this, and give you a stamped analysis. The building department may even require that your calculations be done by a professional. I'm sorry I don't have more help for you.

I went to the website I always go to, to contact Donn Harter, and found he had retired in February of this year, and they have not found a replacement, and have shut down most of their activities. I understand he plans his own private consulting business.

You might go to http://www.glasspublications.com/ which is where they are continuing to offer the publications he developed. There is a phone number there, and they can probably tell you how to contact Donn if you would like him to consult with you on this. He is an exceptionally nice person, and I doubt he is out to make a fortune. He was always very giving of his time in the past. However, experts do deserve to be paid for their services when they are saving others lots of money. In that way, they can also continue to give free assistance. I know if I didn't have a way to sell my manual on ADA signs, or to make occasional consulting fees, I would not have time to answer questions here, or be one of the experts on the building codes panel, volunteer for the ANSI Committee, or for three state committees!

Thanks, and sorry I do not have the personal expertise to do other than try to direct you to help.

Sharon Toji