Glazing Design Analysis Using NGA's Engineering Standards Manual and Heavy Glass Door Design Guide

Even seasoned glazing industry professionals might feel intimidated when opening a manual named Engineering Standards Manual. The Heavy Glass Door Design Guide may also feel, well, heavy. 

No need to fear. 

Structural glazing engineering expert Melissa Szotkowski of Oldcastle BuildingEnvelope provides a tutorial on both manuals during NGA’s Thirsty Thursday webinar on March 18, 2021.

Miss the webinar? It’s not too late. Check it out for free and on-demand as part of BEC Presents on glass.org. The two manuals are available for purchase in the NGA store: Engineering Standards Manual (ESM) and Heavy Glass Door Design Guide (HGDDG). 

Here's a quick rundown:

The tables in these two manuals can be used to determine minimum allowable glass thickness, open joints widths that do not allow fingers to be inserted or trapped, and appropriate hardware selection for interior glass walls and heavy glass doors. Szotkowski gave three examples illustrating how to use the tables in these complementary manuals to help design typical glazing systems.  

One example is an A-style door with patch fittings at the top and bottom in an opening with full height sidelites set in top and bottom channels, with a transom over the door.                  

1. Start this analysis with HGDDG Table 4 to review door height, door width and door weight for patch fittings and floor closer to ensure the opening is properly configured.  

2. Next, review the glass thickness required due to the joint between the door and sidelite for the sidelite height by finding the worst-case thickness in the first and third columns of ESM Table 12. 

3. If the opening has additional adjacent sidelites beyond the door area and you would like to consider different thicknesses for these sidelites, review the joints between the adjacent sidelites for the height of the opening.  

• If the joints are open, refer to the first and third columns of ESM Table 12.  
• Or, if the joints are linked with permanent clips or silicone, refer to the second and fourth columns of ESM Table 12.

4. Once the glass thickness of the adjacent sidelites is determined, go back to HGDDG Table 4 to double-check the hardware limitations for the chosen glass thickness.  

• If the previously-chosen patch fitting and closer works, the analysis is complete.   
• If not, repeat the analysis until an appropriate combination of glass thickness and hardware is found.   

5. Note: when in doubt, consult a structural engineer with experience in glazing design. Follow all applicable building code requirements regarding safety glazing in hazardous locations.  

Want more info? Watch the Webinar