First, we should cover a couple of terms. Grade is the craftsmanship of a work product. For example, windows of superior craftsmanship are going to cost a lot more than those of poor craftsmanship. And for good reason. Quality on the other hand is the degree to which something meets specification. To use windows again, both a high and low-grade window can have excellent quality.

Code is a standard to keep building occupants safe. Code is not a measurement of grade or quality. A high-end grade (meticulously handmade), high-quality guardrail (every measurement is within 1/64″) could very easily not meet code (i.e. baluster allows a four-inch sphere to pass through).

Speaking in very broad generalities – code is the bare minimum. In some cases, those bare minimums are pretty silly, And in others, they’re incredibly important and leave a lot to be desired.

The summary here is that there’s a balance to be met between budget, grade, and quality – while meeting or exceeding code. There are places (like windows) where code is going to specify a vastly inferior grade than what you should look to install. And the quality of that installation can drastically affect performance. Further, that exact scenario could easily meet or exceed the code.