Code watch: Code changes affect glaziers
I’m from California and we have used the Uniform Building Code since about 1927. We’re waiting for the International Building Code to become effective in California, and may have to wait until 2008.
In my consulting work outside of California, I have been able to use the 2000 IBC and 2003 IBC in code compliance reviews and lectures. My work includes serving as a consultant to glaziers and I have found that the IBC code changes have a direct effect on their work, especially in fire-rated construction. I have prepared the following table to review the differences.
Code requirements aside, glaziers should always follow the approved set of plans and make no changes to the window and door schedule, unless they know of a problem. Then, they need to consult with the architect of record.
One potential issue that can arise occurs when a glazier installs replacement glass in an existing building that had been approved under a different code. The example I will use involves glass replacement in Windows A, B and C in the building shown in the sketch on p. 141.
This high-rise office building must be rated construction Type I-FR as indicated in the UBC or Type IA in the IBC and is protected with fire sprinklers. You might have to install safety glazing in this case as all of the panels must comply with requirements in the code for hazardous locations based on the 6 feet by 6 feet size of the panes. Under the provisions of the UBC, Windows A and C would not need to be fire rated. Window B must be fire rated and carry a fire-rating of at least 45 minutes. We can find these requirements in Table 5-A. One single table holds all this information.
However, under the provisions of the IBC, a glass window installed in a fire-rated exterior wall will require some form of “opening protective” as specified in Section 714. To determine the requirements for our example, review IBC Tables 601 and 602. Table 601 initially sets a fire-rating of three hours, then refers to Table 602. It reduces the fire rating based on the fire-separation distance to an adjacent building, adjacent property line or to the center line of the adjacent street. In our case, Windows A and C are located within a wall that is at least 48 feet to the center line of the street and would thus qualify to be nonrated because it is more than 30 feet to the center line. The wall containing Window B is l5 feet from the adjacent property line and must have a minimum fire-rating of one-hour per Table 602. After determining the wall fire rating we now turn to Table 714.2 and find that the window must have a minimum fire rating of 45 minutes.
The end result is that the basic requirement for the subject windows is the same in the IBC as it is in the UBC; it just takes a lot longer to get our answer.
For a 45-minute rating, wired-glass assemblies have been commonly approved by convention. Section 714.3.2 confirms this acceptance level but limits the area and dimensions of wired glass in Table 714.3.2. In our case, the actual size exceeds the maximum allowable of 54 inches by 54 inches and wired glass would not comply.
In existing buildings, replacement glass must comply as required for new installation as stated in IBC Section 3404.1. Therefore, if a glazier is tasked with replacing glass in a storefront, he or she is faced with prevailing through the various IBC code sections to determine if the wall and the glass must be rated. In any of these cases, the glazier needs to obtain a permit, discuss the job with the plan checker or inspector and then specify the rating of each glass panel on the permit.